A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  

  Subjects -> ELECTRONICS (Total: 207 journals)
The end of the list has been reached or no journals were found for your choice.
Similar Journals
Journal Cover
IEEE Journal of Emerging and Selected Topics in Power Electronics
Journal Prestige (SJR): 1.657
Citation Impact (citeScore): 7
Number of Followers: 53  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2168-6777 - ISSN (Online) 2168-6785
Published by IEEE Homepage  [228 journals]
  • IEEE Journal of Emerging and Selected Topics in Power Electronics
           Publication Information

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • IEEE Industry Applications Society Information

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Guest Editorial Special Issue on Failure Mechanisms, Fault
           Characterization, and Condition Monitoring of Power Electronics Components
           and Systems

    • Free pre-print version: Loading...

      Authors: Bilal Akin;Stephanie Watts Butler;Huai Wang;
      Pages: 4950 - 4951
      Abstract: This Special Issue aims to integrate the knowledge base on failure mechanisms, fault characterization, and condition monitoring of power electronics components. In today’s world, power electronics and energy conversion systems play a crucial role in enabling electrification of transportation, modern integrated grid and renewable energy systems to name a few. These systems are often subjected to mechanical and electrical stresses, temperature swings, and vibration that contribute to increased equipment failures, where failed components cause unexpected interruptions, serious safety issues, or significant operational losses. In order to overcome these issues, active fault prognostics and health management techniques have been gaining interest lately. These techniques involve comprehensive understanding of failure mechanisms/modes obtained by accelerated aging tests, multiphysics modeling and physics-of-failure analyses. Based on the identified failure precursors from these analyses, online/insitu condition monitoring and early warning tools are developed for various components and systems. Data sets obtained by monitoring tools can be used to update the lifetime prediction algorithms and actively predict failures. Moreover, these steps are essential for training and data processing in AI and ML techniques which can potentially leverage PHM solutions. Finally, research in various active life extension and health management techniques is of particular interest for power converters.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Active Junction Temperature Control for SiC MOSFETs Based on a
           Resistor-Less Gate Driver

    • Free pre-print version: Loading...

      Authors: Xiaofeng Ding;Xinrong Song;Zhihui Zhao;Zhenyu Shan;Binbin Wang;
      Pages: 4952 - 4964
      Abstract: Junction temperature fluctuation is the main cause of failure of power devices including silicon carbide (SiC) MOSFETs, and active junction temperature control is an effective way to improve their reliability. Most existing methods of active junction temperature control rarely consider the system efficiency and the complexity of hardware implementation, which limits their applications. This article proposes an active junction temperature control method for SiC MOSFETs based on a resistor-less gate driver, which consists of two auxiliary MOSFETs with adjustable gate–source voltages. Hence, the switching loss of the SiC MOSFET can be continuously and accurately adjusted to mitigate the efficiency suffer with the junction temperature control. The power loss model of SiC MOSFETs with the proposed gate driver was established. The design principle of the junction temperature controller is introduced. The experimental results show that the junction temperature fluctuation is reduced by 24.1%, and that the lifetime of the SiC MOSFET is prolonged by 3.92 times via using the proposed junction temperature control method. The energy loss of the prototypical inverter is decreased by 4.15% over the whole testing period. The experiment was conducted with SiC MOSFETs, and the proposed method is also suitable for other Si-based semiconductor devices.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Gate-Driver Integrated Junction Temperature Estimation of SiC MOSFET
           Modules

    • Free pre-print version: Loading...

      Authors: Slavko Mocevic;Vladimir Mitrovic;Jun Wang;Rolando Burgos;Dushan Boroyevich;
      Pages: 4965 - 4980
      Abstract: SiC MOSFET power modules are becoming global solutions in systems operating in harsh environment, and due to large economic implications, achieving reliability of such systems is of utmost importance. Thereby, this article is focused on improving the reliability of the SiC MOSFETS, accomplished by generating intelligence on the gate driver (GD) with providing insight on real-time behavior of relevant switch information. The device switch current $ {I_{mathrm {d}}}$ , apart from being used for short-circuit detection assessing the short-term reliability, in the combination with the ON-state drain-to-source voltage $ {V_{mathrm {ds,mathrm{scriptscriptstyle ON}}}}$ enables the possibility of online junction temperature ( $ {T_{mathrm {J}}}$ ) estimation. The knowledge of $ {T_{mathrm {J}}}$ can enable active thermal control as well as condition monitoring of the SiC MOSFET device such as state-of-health, remaining useful life, and maintenance scheduling, tackling the long-term reliability aspects. With the aid of a field-programmable gate array (FPGA) on GD, a lookup table (stored in the FLASH memory on GD) containing device output characteristics is assessed, enabling real-time $ {T_{mathrm {J}}}$ monitoring for both devices in the commercial SiC MOSFET half-bridge module configuration. Following the developed GD prototype, $ {T_{mathrm {J}}}$ is verified in pulsed operation with maximum error less than 5 °C having excellent repeatability of ±1.2 °C and is furthermore verified-in continuous operation showing promising results. In addition, degradation monitoring and aging compensation scheme are discussed, with the goal of maintaining the accuracy of the $T_{mathrm {j}}$ estimation throughout device’s lifetime.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Quasi-Distributed Temperature Detection of Press-Pack IGBT Power Module
           Using FBG Sensing

    • Free pre-print version: Loading...

      Authors: Hai Ren;Li Ran;Xianming Liu;Li Liu;Siniša Djurović;Huaping Jiang;Mike Barnes;Philip A. Mawby;
      Pages: 4981 - 4992
      Abstract: In situ temperature near the chips in a multiple-chip power semiconductor module is important information for thermal design validation, condition monitoring, and overheat protection. Due to the compact packaging structure and clamping force, online detection of the temperature is challenging for a press-pack module. This study attempts to achieve measurement by integrating optical fiber Bragg grating (FBG) sensors into the device. Different integration schemes are examined using experiments and theoretical analysis to show the effects on the transient performance. It is shown that FBG sensors with plate housing can effectively indicate the transient temperature ripple in normal converter operation, owing to the fast dynamic response of a small size sensor. The package integration has only minimal effects on the original distributions of electrical, thermal, and mechanical quantities within the power module.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Temperature-Dependent Analytical Model of SiC MOSFET Short-Circuit
           Behavior Considering Parasitic Parameters

    • Free pre-print version: Loading...

      Authors: Pengfei Xiang;Ruixiang Hao;Xiaojie You;
      Pages: 4993 - 5006
      Abstract: The superior electrical and thermal characteristics of silicon carbide (SiC) MOSFETs bring major challenges to its short-circuit reliability. To fully understand its short-circuit mechanism, estimate its safe operating area, and provide guidance for circuit design, it is crucial to establish a theoretical model to quantize the relationship between circuit parameters and short-circuit behavior of SiC MOSFETs. A temperature-dependent analytical model considering the parasitic inductances, nonlinear junction capacitances, and temperature dependence of the channel current is proposed in this article, which uses only the parameters in the datasheet or provided by manufacturers. The proposed model is established based on the analysis for each short-circuit stage in both single-device configuration and half-bridge configuration, and the quantitatively analytical results of the transient short-circuit waveforms, energy loss, and junction temperature rise can be calculated by solving the model. The accuracy of the analytical model is verified by comparing the analytical results with the experimental results. Furthermore, the effects of varied parameters on the short-circuit behavior are evaluated by the proposed analytical model. And the corresponding circuit design guidance for higher short-circuit reliability is given.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • An Online Junction Temperature Monitoring Correction Method for SiC
           MOSFETs at Different Parasitic Parameters

    • Free pre-print version: Loading...

      Authors: Peng Sun;Yahui Guo;Tao Wu;Zhibin Zhao;Pengyu Lai;Zhong Chen;Lei Qi;Xiang Cui;
      Pages: 5007 - 5018
      Abstract: Due to the remarkable performance of silicon carbide (SiC) metal–oxide–semiconductor field-effect transistor (MOSFET) on high temperature, it is promising in future applications in various applications. The accurate online junction temperature based on dynamic temperature-sensitive electrical parameters (TSEPs) is significant for the protection and condition monitoring, which can prolong or monitor the lifetime of SiC MOSFET devices. In this article, four different dynamic TSEPs, including turn-on delay time, turn-off delay time, and maximum current turn-on and turn-off switching rates, are theoretically analyzed taking the parasitic parameters into consideration. The experimental analysis of the influence of parasitic parameters ’ dynamic TSEPs is carried on using a buck converter test setup. Based on the theoretical and experimental analyses, a junction temperature correction method is proposed for SiC MOSFET. The online junction temperature monitoring experiments are used to verify the accuracy and effectiveness of the proposed method. The results show that the proposed correction method can largely eliminate the junction temperature monitoring error at different parasitic parameters. The maximum measurement error is reduced from 147 °C to 4.7 °C after correction.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Cumulative Hot-Electron Trapping in GaN-Based Power HEMTs Observed by an
           Ultrafast (10 V/Ns) On-Wafer Methodology

    • Free pre-print version: Loading...

      Authors: Nicola Modolo;Carlo De Santi;Andrea Minetto;Luca Sayadi;Sebastien Sicre;Gerhard Prechtl;Gaudenzio Meneghesso;Enrico Zanoni;Matteo Meneghini;
      Pages: 5019 - 5026
      Abstract: The goal of this article is to advance the understanding of the impact of hard switching on the dynamic performance of GaN-based high electron mobility transistors (HEMTs). To this aim, we developed a fast (10 V/ns) on-wafer system for testing devices in hard switching. The system has been used to study the reliability of several $W_{G}=2$ mm p-type GaN HEMTs with different $L_{text {GD}}$ or buffer properties. First, we show that by optimizing the drain node capacitance, we can speed up the hard-switching transition to a few ns, even on-wafer level. Second, repeating the experiment by using multiple frequencies, from 1 to 100 kHz, we demonstrate that, in real-world applications, cumulative turn-on stress has a much stronger effect on $R_{mathrm {ON}}$ compared with OFF-state stress. Third, by comparing the results on identical devices having shorter $L_{text {GD}}$ , we pinpoint hot electrons as the main mechanism in the device degradation, ruling out the contribution of self-heating. Finally, by comparing three wafers with different processing conditions (different passivation, different buffer), we suggest that trapping phenomena related to hot electrons happen in ns time scale and that the properties of the buffer can significantly impact the dynamic performance of the devices in hard switching.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Degradation of SiC MOSFETs Under High-Bias Switching Events

    • Free pre-print version: Loading...

      Authors: Joseph P. Kozak;Ruizhe Zhang;Jingcun Liu;Khai D. T. Ngo;Yuhao Zhang;
      Pages: 5027 - 5038
      Abstract: Evaluating the robustness of power semiconductor devices is key for their adoption into power electronics applications. Recent static acceleration tests have revealed that SiC metal–oxide–semiconductor field-effect transistors (MOSFETs) can safely operate for thousands of hours at a blocking voltage higher than the rated voltage and near the avalanche boundary. This work evaluates the high-bias robustness of SiC MOSFETs under continuous, hard-switched, turn-off stresses with a dc bias higher than the device rated voltage. Under this high-bias switching condition, SiC MOSFETs show degradation in merely tens of hours at 25 °C and tens of minutes at 100 °C. Two independent degradation and failure mechanisms are unveiled: one present in the gate oxide and the other in the bulk-semiconductor regions, featured by the increase in the gate leakage current and the drain leakage current, respectively. The second degradation mechanism has not been previously reported in the literature; it is found to be related to the electron hopping along with the defects in semiconductors generated in the switching tests. The comparison with the static acceleration tests reveals that both degradation mechanisms correlate to the high-bias switching transients rather than the high-bias blocking states. These results suggest the insufficient robustness of SiC MOSFETs under high-bias, hard-switching conditions and the significance of using switching-based tests to evaluate the device robustness.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Methodology for Enhanced Surge Robustness of 1.2-kV SiC MOSFET Body Diode

    • Free pre-print version: Loading...

      Authors: Hongyi Xu;Na Ren;Zhengyun Zhu;Jiupeng Wu;Li Liu;Qing Guo;Kuang Sheng;
      Pages: 5039 - 5047
      Abstract: In this work, the influences of P-well design and turn-off gate-to-source bias on the surge robustness of SiC MOSFET’s body diode are studied. Devices with high and low P-well doping concentration designs are stressed with surge current pulses when the gate-to-source is biased with 0 or −5 V. The gate-to-source bias is found to have effects on the surge capability of the low P-well doping-designed device. In the case of 0-V bias, the channel is prone to turning on and acquires a higher surge capability than the devices under the −5 V. On the other hand, the surge capability of high P-well doping-designed device is found less influenced by the gate-to-source bias. Furthermore, threshold voltage instability after repetitive surge pulses is also investigated. The device with low P-well doping shows better threshold stability due to its lower interface trap density. Based on the results above, a design methodology is proposed from the view of device mechanism and operation condition. Relatively low P-well doping design and negative gate bias are recommended for SiC MOSFET, as they can improve the single-pulse surge robustness of body diode and minimize the threshold voltage instability in repetitive surge pulse events.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Dynamic Avalanche Limit and Current Filamentation Onset Limit in
           4H-Silicon Carbide High-Voltage Diodes

    • Free pre-print version: Loading...

      Authors: Daniel Johannesson;Muhammad Nawaz;Hans-Peter Nee;
      Pages: 5048 - 5058
      Abstract: Dynamic avalanche (DA) phenomena and current filament (CF) formation are two extreme conditions observed in high-power devices, setting the maximum limit on turn-on/off current capability and di/dt in silicon (Si)-based bipolar devices. The properties of the silicon carbide (SiC) material enable devices with increased resilience for DA and CF compared with Si counterparts, and thus the safe-operating-area (SOA) limits may be extended. In this study, the limit of DA and CF in SiC-based semiconductor structures are investigated by numerical technology computer-aided design (TCAD) simulations, for different current levels, di/dt, and temperatures for high-voltage devices (e.g., 20-kV class). DA is first indicated for di/dt beyond 105 kA/ $mu text{s}$ for current densities in the range of 50–1000 A/cm2, at 448 K. Similarly, stray-inductance-induced avalanche conditions are initiated above 33 kA/ $mu text{s}$ , while CF is initiated for di/dt starting from 83 kA/ $mu text{s}$ for current densities in the range of 8.3 kA/cm2. Moreover, the effects of the stray inductance in the main circuit loop are studied which may cause critical voltage transients during certain operating conditions. The outcome of the study may be useful to determine SOA limits and to be used as input for power electronic converter design and gate driver design for high-power electronic systems.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • 1200-V SiC MOSFET Short-Circuit Ruggedness Evaluation and Methods to
           Improve Withstand Time

    • Free pre-print version: Loading...

      Authors: Diang Xing;Boxue Hu;Minseok Kang;Yue Zhang;Suvendu Nayak;Jin Wang;Anant K. Agarwal;
      Pages: 5059 - 5069
      Abstract: This article presents the short-circuit (SC) capability evaluation of TO-247-3 packaged silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs) based on tests under different drain biases and gate biases. Compared with the 900-V Si super-junction MOSFET and the 1200-V Si trench-gate field-stop insulated gate bipolar transistor (IGBT), SiC devices show higher saturation current per die area, which requires more rigorous chip design consideration to reach an acceptable SC withstand time (SCWT). The test results also reveal that the SC withstand capability of SiC MOSFETs can still be enhanced. Thus, in both chip design and detection circuits, several novel approaches investigated in recent years, which could potentially improve SC ruggedness of SiC device-based systems, are discussed at the end of this article.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Understanding the Degradation of 1.2-kV Planar-Gate SiC MOSFETs Under
           Repetitive Over-Load Current Stress

    • Free pre-print version: Loading...

      Authors: Hengyu Yu;Shiwei Liang;Jun Wang;Xi Jiang;Bo Wang;Yu Yang;Yuwei Wang;Yiqiang Chen;
      Pages: 5070 - 5080
      Abstract: Silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) has superior performances in terms of high switching frequency and low power loss, but its widespread applications in markets have been partly hindered by its ruggedness and reliability. Overcurrent operation is a common phenomenon which causes overheat of power devices and further leads to degradation or even device failures in power electronic systems. However, in- depth degradation mechanism and limiting factors of repetitive overcurrent capability have not been comprehensively studied yet. In this article, we investigated the conduction and the switching overcurrent stress separately to figure out the roles of each operation processes in the degradation of 1.2-kV SiC planar-gate MOSFETs for the first time. It is observed that the conduction overcurrent stress causes a positive shift of threshold voltage, while the switching overcurrent stress leads to a negative shift of threshold voltage as well as larger gate leakage current. Electrons captured at the SiC/SiO2 interface may be the reason for the positive shift of threshold voltage, while the negative shift of threshold voltage may be due to the injection and accumulation of the holes into the gate oxide at JFET and near-channel region. Both experimental results and simulation analysis show that the switching overcurrent stress plays a major role in the degradation of 1.2-kV SiC planar-gate MOSFETs under repetitive overcurrent stress. In addition, the influence of major limiting factors, including overcurrent level, overcurrent duration, and drain–source voltage, is also investigated to evaluate the reliability of SiC planar-gate MOSFETs under different overcurrent conditions, which will provide a useful guidance for dedicated design and utilization of SiC MOSFETs.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Detection and Identification of Power Device Failures Using Discrete
           Fourier Transform for Fault-Tolerant Operation of Flying Capacitor
           Multilevel Converters

    • Free pre-print version: Loading...

      Authors: Sai Tang;Jun Wang;Chao Zhang;Daming Wang;Xin Yin;Zhikang Shuai;Zheng John Shen;
      Pages: 5081 - 5091
      Abstract: For a flying capacitor multilevel converter (FCMC), prompt detection of power switch failures is crucial for fault-tolerant operation. This article presents a new technology for identifying and locating faulty cells in FCMC. Mathematical derivation points out that different fault types and locations will present different high-frequency harmonics. The new technology extracts high-frequency harmonics in the switch node voltage and looks up a preestablished table to identify the fault type and location. The discrete Fourier transform (DFT) can be easily performed to analyze the harmonic using the built-in IP core in field-programmable gate array (FPGA). For an FCMC with any number of levels, the new approach requires only one voltage sensor and can accurately locate the faulty cell after one carrier cycle when the fault occurs. Both simulation and experimental results validate the proposed concept on a five-level 100-kHz GaN FET-based FCMC prototype. Furthermore, we have experimentally demonstrated the fault-tolerant operation of the FCMC after a switch short and open fault is detected and identified by the new technique.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Voltage-Based Multiple Fault Diagnosis Approach for Cascaded H-Bridge
           Multilevel Converters

    • Free pre-print version: Loading...

      Authors: Dong Xie;Huai Wang;Xinglai Ge;Qingli Deng;Bin Gou;Lei Ma;
      Pages: 5092 - 5106
      Abstract: This article proposes a fast and robust open-circuit fault diagnosis method without additional sensors for cascaded H-bridge multilevel converters (CHBMCs). The method is based on the error between the actual input-side voltage and the estimated one, with one detection threshold and $2n$ comparators in $n$ cascaded H-bridges. Benefitted from the simple design of the fault location, spike elimination, and parameter estimation, with the lower implementation burden, the single and multiple faults in arbitrary positions are accurately identified within a fundamental cycle, and the diagnostic robustness is guaranteed under different transient changes. In view of the low complexity, the proposed scheme can be easily applied to the CHBMCs with arbitrary modules. The experimental results from a CHBMC prototype verify the effectiveness of the proposed method under different operating conditions and fault scenarios.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • In Situ Diagnosis of Wire Bonding Faults for Multichip IGBT Modules Based
           on the Crosstalk Effect

    • Free pre-print version: Loading...

      Authors: Wuyu Zhang;Kun Tan;Bing Ji;Lei Qi;Xiang Cui;Jixuan Wei;Xiangyu Zhang;
      Pages: 5107 - 5117
      Abstract: Introducing bond wire diagnosis for multichip insulated gate bipolar transistor (IGBT) modules is key to the health monitoring of modular multilevel converters (MMCs), which allow for improved field robustness, reliability, and reduced maintenance cost. This article leverages the crosstalk phenomenon during switching transitions to detect the chip open-circuit faults caused by the bond wire lift-off using typical half-bridge IGBT modules in a multichip-parallel configuration. The cycle-controlled, nonintrusive measurement is conducted under normal operation, when the device under test is in OFF-state and its complementary switch is during switching transitions. Two specialized health-sensitive parameters arising from the dynamic gate loop waveforms are identified and evaluated, including: 1) the gate voltage $V_{mathrm {GE(t3)}}$ when the declining collector voltage reaches zero and 2) the negative peak gate voltage $V_{mathrm {GE(t4)}}$ . The sensitivity and stability of these two parameters are compared through theoretical analysis, circuit simulation, and practical verification. The results show that $V_{mathrm {GE(t4)}}$ is more suitable for online monitoring, while $V_{mathrm {GE(t3)}}$ is more sensitive than $V_{mathrm {GE(t4)}}$ . With managed complexity in gate drives, this proposed health awareness approach is feasible in the submodules of MMC applications, but it can also be used in other power converter topologies incorporating the half-bridge structure.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Condition Monitoring of Power Electronic Systems Through Data Analysis of
           Measurement Signals and Control Output Variables

    • Free pre-print version: Loading...

      Authors: Firat Yüce;Marc Hiller;
      Pages: 5118 - 5131
      Abstract: A major disadvantage of existing condition monitoring methods is the need for additional sensors and measuring equipment. In this work, this disadvantage is eliminated by completely avoiding additional hardware. Instead, software-based methods from the field of machine learning are used. Therefore, measurement signals and control output variables are utilized, which are acquired and processed in any power electronic system for the purpose of converter control. The publication focuses on two main converter components: power semiconductors and dc-link capacitor. For each component, the aging mechanisms that have been studied in the literature are explained. Based on the aging mechanisms, the degradation indicators are identified. Then, a converter model is built that allows the variation of degradation indicators in order to analyze their effects on the available dataset. These findings form the basis for mathematical models, which detects future failure mechanisms of this type during converter operation. The test setup must offer the possibility of generating reproducible failure cases in various components with the aid of additional failure equipment. Finally, failure mechanisms are intentionally introduced at the test bench in order to validate the methodology of the developed approach.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Wear-Out Mechanism of Press-Pack IGBTs Under Accelerated Aging Test

    • Free pre-print version: Loading...

      Authors: Cao Zhan;Lingyu Zhu;Jiangang Dai;Yaxin Zhang;Junjie Liu;Zhanlei Liu;Chenshuo Liu;Shengchang Ji;
      Pages: 5132 - 5141
      Abstract: The study of wear-out mechanism of press-pack insulated-gate bipolar transistors (IGBTs) (PPIs) is conducted insufficiently now. In this article, both the numerical and experimental methods are utilized to investigate the wear-out mechanism of PPIs. After conducting an accelerated aging test, three wear-out modes are observed: fretting scratches, cracks next to the additional metallization area, and oxidation of the additional metallization area. The oxidation of the additional metallization area is the newly found wear-out mode. In order to explain the deterioration mechanism of the modes, the fully coupled multiphysical model considering the aging state inside PPIs is utilized to analyze the temperature, pressure, and voltage distribution. The results show that fretting wear is the main reason for the three wear-out modes. First, the fretting scratches caused by fretting wear lead to the increment of surface roughness. The junction temperature and thermal resistance of the PPI both show approximately linear increment with surface roughness, while the saturation voltage remains unchanged. Second, high mechanical pressure during fretting wear results in the fatigue cracks next to the additional metallization area. Finally, it is found that the fretting wear also leads to the oxidation of the additional metallization area.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Real-Life Mission Profile-Oriented Lifetime Estimation of a SiC
           Interleaved Bidirectional HV DC/DC Converter for Electric Vehicle
           Drivetrains

    • Free pre-print version: Loading...

      Authors: Sajib Chakraborty;Mohammed Mahedi Hasan;McGahan Paul;Dai-Duong Tran;Thomas Geury;Pooya Davari;Frede Blaabjerg;Mohamed El Baghdadi;Omar Hegazy;
      Pages: 5142 - 5167
      Abstract: The rapid growth of battery electric vehicles (BEVs) in the automotive field has led to the need for improving their drivetrain performance, mainly focusing on the extension of the battery operating range. However, the majority of performed technical assessments only consider battery state-of-charge (SoC) and depth of discharge, while neglecting the effects on lifetime and failure probability of power electronic components, more specifically the emerging wide bandgap (WBG)-based technologies. Toward fulfilling this gap, the EV market demands lifetime estimation carried out under real-life mission profile to confirm efficiency and reliable operation of EV power electronics for an extended range meeting the EVs lifetime requirements. In this regard, this study proposes a versatile experimental device-under-test setup to investigate a novel stepwise holistic system-level lifetime estimation approach for BEV drivetrains equipped with SiC interleaved bidirectional HV dc/dc converter (IBC). To this end, three different real-life mission profile use-cases are investigated in this article and they provide systematic stress-based lifetime estimation, statistical analyses, and validations in comparison. The study outcome highlights realistic information related to significant impacts of operation range and battery SoC features on the IBC lifetime from all aspects.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Study of Electrical Contacts Fatigue and Degradation Evaluation for
           Press-Pack IEGT Under Power Cycling Tests

    • Free pre-print version: Loading...

      Authors: Siyang Dai;Zheng Liu;Zhiqiang Wang;Yao Zhao;Guofeng Li;
      Pages: 5168 - 5180
      Abstract: The electrical contact status between metal layers in a press-pack injection enhanced gate transistor (PP-IEGT) is essential information for the reliability of the whole device. This article employs the numerical method, microscopic detection, and power cycling test (PCT) to qualify the contact degradations and performance in PP-IEGT. First, the contact status of metal pair aluminum–molybdenum in a single-chip module is described through the finite element method (FEM). Then, the contact fatigue of the single-chip module is estimated by the microdetection of the chip surface and the monitor of contact resistance during PCT. Finally, PCTs are conducted on parallel branches to explore contact degradation under different contact statuses. The results show that the chip is subjected to fretting wear and cracks due to the periodic expansion and shrink. In the aging process, the contact resistances display a linear growth trend and have a significant impact on the electrical parameter shift. Moreover, the degradation of the branch with insufficient contact is more serious, especially under smaller clamping force and longer heating duration.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Reliability and Lifetime Prediction Model of Sintered Silver Under
           High-Temperature Cycling

    • Free pre-print version: Loading...

      Authors: Paul Paret;Joshua Major;Douglas DeVoto;Sreekant Narumanchi;Chao Ding;Guo-Quan Lu;
      Pages: 5181 - 5191
      Abstract: Although excellent reliability has been reported for sintered silver as a die-attach material under both thermal and power cycling loads in power electronics applications, the promise of this material as a large-area attachment at temperatures beyond 200 °C needs to be investigated. This article presents insights into the thermomechanical behavior and reliability of sintered silver under extreme thermal cycling conditions. In this study, we bonded sintered silver samples and subjected it to a thermal cycling profile of −40 °C to 200 °C with high ramp rates. We periodically monitored samples under thermal cycling to detect the presence of any failure mechanisms using a scanning acoustic microscope. We also included 95Pb5Sn solder in the study to obtain reference data. Results show the occurrence of cracks in sintered silver followed by a rapid rate of crack growth that exceeded the failure criterion in just 50 cycles. The predominant failure mechanism we observed was adhesive failure. As a large-area attachment, solder exhibited a higher reliability than sintered silver but failed within 100 cycles. Finally, we performed thermomechanical modeling to compute strain energy density values and correlated these with the experimentally observed crack growth rates to formulate a lifetime prediction model for sintered silver.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Online Capacitance Monitoring for DC/DC Boost Converters Based on
           Low-Sampling-Rate Approach

    • Free pre-print version: Loading...

      Authors: Zhaoyang Zhao;Pooya Davari;Yaoqiang Wang;Frede Blaabjerg;
      Pages: 5192 - 5204
      Abstract: Aluminum electrolytic capacitor (Al-Cap) is widely used in dc/dc converters to suppress voltage ripple and store energy to stabilize the output voltage. However, Al-Cap is one of the most vulnerable parts in power electronic converters, and its capacitance ( $C$ ) is an important parameter for indicating the health status. For the purposes of condition monitoring (CM), small-signal voltage and current ripples are usually used to estimate the capacitance of Al-Caps. Unfortunately, the ripples of dc/dc converters have the features of small amplitude and high frequency, which increases the complexity for data acquisition and processing. Moreover, the amplitude of ripple changes as the operation condition of converters changes (e.g., the load changes), and it will increase the complexity of sampling circuits. Considering this issue, this article proposes a transient charging profile-based capacitance estimation scheme for dc/dc boost converters, which aims to reduce the sampling frequency. Taking a 24-48-V boost converter as a case study, simulation and experimental results demonstrate the feasibility of the proposed scheme for converters with different operating conditions and circuit parameters, and the estimation error is less than 3%.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Breakdown Voltage Instability Mechanism on the Field Limiting Rings Edge
           Termination of Buried Layer Rectifier

    • Free pre-print version: Loading...

      Authors: Qiang Yuan;Zehong Li;Yishang Zhao;Tongyang Wang;Jiali Wan;Yang Yang;Luping Li;Min Ren;
      Pages: 5205 - 5213
      Abstract: In this article, an innovated buried layer rectifier (BLR) breakdown voltage (BV) instability has been tested and analyzed. Under the reverse current stress (RCS) condition, the BV read-out profiles show walk-in and walk-out phenomena. Based on the experimental results and surface traps theory, a sort of time-dependent degraded simulation is developed by TCAD tools, which is considered with hydrogen depassivation and diffusion process. In order to explore the inner mechanism, the dynamic electric parameters are analyzed during the degraded period. Due to the hole interface traps, the termination Si-SiO2 surface leakage current is deteriorated and the depletion boundary is shrunk, which reveal the BV values instability. Thus, the proposed physical model could clearly explain the whole process of degradation, while it fits BV and junction temperature curves to the experimental results identically. Furthermore, the investigated mechanism will be helpful to future device design and failure situations analysis.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • An Evaluation on Thermal Performance Improvements for SiC Power Module
           Integrated With Vapor Chamber in MMC

    • Free pre-print version: Loading...

      Authors: Binyu Wang;Laili Wang;Shijie Wu;Zhenpeng Hou;Wei Mu;Fengtao Yang;Jinjun Liu;Yongmei Gan;
      Pages: 5214 - 5225
      Abstract: In this article, the improvements in thermal performances of the SiC power module integrated with vapor chamber (VC) under modular multilevel converters (MMCs) working conditions are evaluated for the first time. The copper baseplate of the SiC power module is replaced by a VC with the same size, which has the advantages of good temperature uniformity, excellent thermal conductivity, compactness, flexible design, high integration, and low cost. The FEM simulation results show that the hotspot temperature, maximum temperature difference among the chips, and low-frequency temperature swing (TS $_{L}$ ) can be significantly reduced. Then, the well-designed VC is customized and integrated with the SiC power module. Finally, the advantages of VC in improving the thermal performances of power modules in SiC-MMC are validated by the comparative experiment. The experimental results show that the local over-temperature and thermal unbalance of the power module in SiC-MMC can be significantly mitigated.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Single-Phase Five-Level IT-Type NPC Inverter With Improved Efficiency and
           Reliability in Photovoltaic Systems

    • Free pre-print version: Loading...

      Authors: Ui-Min Choi;June-Seok Lee;
      Pages: 5226 - 5239
      Abstract: The reduction in the cost of photovoltaic (PV) energy is still required to be competitive as an alternative energy source. The efficiency and reliability of PV inverters are important aspects to be enhanced to reduce the cost of PV energy since it is closely related not only to the annual energy production but also to the reduction in operational and maintenance costs of PV systems. In this article, a single-phase IT-type NPC inverter with one-leg clamping pulse width modulation (OLC-PWM) is proposed for efficiency and reliability improvements. The proposed IT-type NPC inverter with OLC-PWM can improve the efficiency by taking the advantages of I-type and T-type NPC inverters regarding the power loss. Furthermore, its reliability has been improved compared with the conventional I-type and T-type NPC inverters. The IT-type NPC inverter also has an ability to balance the neutral-point voltage. The superiorities of the proposed IT-type NPC inverter in terms of reliability and efficiency are validated through the simulations and experiments by comparing the reliability and efficiency of the conventional I-type and T-type, asymmetric I-type and T-type, and IT-type NPC inverters.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Multiobjective Design Optimization of Extremely Low-Frequency Power
           Amplifier Considering Accuracy, Volume, and Reliability

    • Free pre-print version: Loading...

      Authors: Rong Han;Qianming Xu;Hongqi Ding;Bing Gao;Lei Wang;Cheng Tang;Junkun Zhang;An Luo;
      Pages: 5240 - 5251
      Abstract: The extremely low-frequency power amplifier (ELFPA) used in the communication system is required to have high output accuracy, small size, and high reliability under complex mission profiles simultaneously. However, the system parameters that determine these performances are coupled with each other, and it is difficult to directly select the optimal solution that meets all output performances at the same time. Thus, a new high reliable parameters design method is proposed for ELFPA system, which can simultaneously consider the relationship among multiple mutually coupled, nonlinear control variables and output performances. Moreover, the multiobjective particle swarm optimization (MOPSO) algorithm is used to search for the Pareto-optimal solutions and the best design. The use of this optimization algorithm aims to avoid the empirical trial-and-error method for adjusting the parameter values and quickly find the system parameter value that best trades off the total harmonic distortion (THD), volume, and lifetime of the system. To illustrate the superiority of the proposed approach, the proposed parameter design process of a 5-kW power amplifier is verified by both simulation and experimental results.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Reliability Analysis of Large-Area, Low-Pressure-Assisted Silver Sintering
           for Medium-Voltage Power Modules

    • Free pre-print version: Loading...

      Authors: Jacob Gersh;Christina DiMarino;Douglas DeVoto;Paul P. Paret;Joshua Major;
      Pages: 5252 - 5259
      Abstract: Multi-layer insulating ceramic substrates can enable medium-voltage (MV) power modules with reduced peak electric field. This benefit is particularly important for MV silicon carbide (SiC) MOSFETs due to their higher operating voltages. Large-area, low-pressure-assisted silver sintering is a potential solution for bonding substrates to create a multi-layer structure. The voiding content and defect density of the bond used to create the multi-layer substrate stack-up are critical to the reliability of the power module and thermal performance, as this bond is in the primary path for heat dissipation in the power module structure. Samples of two-layer direct bonded aluminum (DBA) stacks have been fabricated and subjected to thermal cycling to analyze their reliability. Passive thermal cycling from −40 °C to 200 °C was performed. Cross sections were cut at pre-determined intervals and imaged with scanning electron microscopy (SEM). After 1000 thermal cycles, adhesive failures are observed between the sintered silver and DBA surface. Cross sections were cut and imaged via optical microscope and SEM. Thermal analyzer measurements are recorded on a 10-kV SiC power module using the sintered DBA substrate stacks.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Guest Editorial Special Issue on Power Electronics Systems for Aerospace
           Applications

    • Free pre-print version: Loading...

      Authors: Xinbo Ruan;Pablo Fernández Miaja;Jesús A. Oliver;
      Pages: 5260 - 5263
      Abstract: Aerospace applications have been a major driver for the development of power electronics. The demand of light and efficient power supplies, common both for space and aeronautic applications, spearheaded the research and development efforts around switching mode power systems. Major seminal works in the field, such as those pioneered by Prof. R. D. Middlebrook, were developed under funding from National Aeronautics and Space Administration (NASA). Another example is that average current mode control or transconductance control was developed in the European Space Agency (ESA) laboratories while at the same time peak current mode control was invented in U.S. institutions.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Potentials and Comparison of Inverter Topologies for Future All-Electric
           Aircraft Propulsion

    • Free pre-print version: Loading...

      Authors: Janine Ebersberger;Maximilian Hagedorn;Malte Lorenz;Axel Mertens;
      Pages: 5264 - 5279
      Abstract: Decarbonization of the air transport sector is a major challenge for the upcoming years. To achieve this goal, electrification of the propulsion for small to medium civil aircraft is a key enabler for various concepts, ranging from hybrid over fuel cell to full battery powered aircraft. While small electric aircraft for lower altitudes already exist, it is necessary to extend the power range to several megawatts for passenger aircraft flying at medium to high altitudes. Here, the question of the most promising inverter topology and dc supply voltage level is yet to be answered. Challenges include lightweight, high efficiency, and reliability due to cosmic-ray-induced failures. To address this, a broad range of topologies, covering conventional two-level, three-level inverters, and modular multilevel converters (MMCs), are compared in this article. For this purpose, an inverter design methodology is introduced, including chip area optimization, inverter loss, and weight calculation. As a prerequisite, a loss model for high-voltage silicon carbide (SiC) MOSFETs is derived and used to estimate the characteristics for voltage levels not readily available today. Uncertainty is addressed by covering several scenarios.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Quadrature Signal-Based Control Strategy for Vienna Rectifier Under
           Unbalanced Aircraft Grids

    • Free pre-print version: Loading...

      Authors: Ziliang Xu;Xiaoyong Ren;Zhihao Zheng;Zhiliang Zhang;Qianhong Chen;Zhenyang Hao;
      Pages: 5280 - 5289
      Abstract: In order to eliminate the input current harmonics and dc-link voltage ripples of Vienna rectifier under unbalanced input, a novel control strategy applicable to wide variable frequency (360–800 Hz) aircraft electrical system is proposed in this article. To serve this purpose, current references on natural frame are first derived, which contain quadrature signals of grid voltages. Then, a natural-frame-based control strategy is designed, in which the second-order generalized integrator (SOGI) frequency-locked loop (FLL) is employed for variable frequency grids. Compared with traditional dual-frame control strategy, the proposed strategy reduces the algorithm complexity and has better frequency adaptability. The proposed strategy is suitable for all the unbalanced conditions, which is defined by test procedures DO-160G. Simulation and experimental results verify the effectiveness of the proposed control strategy.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Planar Common-Mode EMI Filter Design and Optimization for High-Altitude
           100-kW SiC Inverter/Rectifier System

    • Free pre-print version: Loading...

      Authors: Xingchen Zhao;Jiewen Hu;Lakshmi Ravi;Dong Dong;Rolando Burgos;Sriram Chandrasekaran;Richard Eddins;
      Pages: 5290 - 5303
      Abstract: Silicon-carbide (SiC) devices are receiving popularity for high-power converter systems in aircraft due to many advantages over silicon counterparts. However, the electromagnetic interference (EMI) problems are more serious with the SiC devices operating at higher switching speeds and higher switching frequencies. The common-mode (CM) EMI filter design of the high-power SiC converter is especially challenging for high-altitude applications due to the harsher requirements of insulation and heat dissipation. The optimization of the parameters and physical design of a CM EMI filter in a 100-kW SiC inverter/rectifier system operating at 50 000 ft is conducted in this article to obtain the highest power density. The effect of the switching frequency on the EMI filter volume and the total power density of the converter system is analyzed. The lower breakdown voltage of air and the higher thermal resistance of natural convection make the conventional design of the CM choke infeasible at high altitudes. A printed circuit board (PCB)-based planar CM choke is designed with the consideration of partial discharge (PD) and heat dissipation at the altitude of 50 000 ft. The structure of the CM choke is optimized with embedded electric-field shielding plates, which controls the electric-field intensity in the air below 300 V/mm. The PCB windings improve the efficiency of heat dissipation at high altitudes and reduce the profile of the CM choke. A Pareto optimization is conducted to minimize the size of the choke and the volume of the final design is only 155 cm3. The experimental results show that the CM noise is reduced effectively with the CM EMI filter. PD is not observed even at the altitude of 50 000 ft and the thermal performance is excellent with a current of 190 A. With the optimization and the dedicated design of the CM EMI filter, the power density of the converter system is up to 33.3 kW/L.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Testing Tool for Converter-Dominated Power System: Stochastic
           Electromagnetic Transient Simulation

    • Free pre-print version: Loading...

      Authors: Pengwei Chen;Liang Lu;Xinbo Ruan;Nian Liu;
      Pages: 5304 - 5317
      Abstract: To investigate the impact of uncertain variability and provide a rigorous testing environment for converter-dominated power systems, this article develops a testing tool called stochastic electromagnetic transient simulation. The tool is derived from the stochastic differential equation (SDE) representing the stochastic process of parameter migration. By inheriting the principle of companion circuit, the dynamic companion circuits of the lumped elements with parameter migration are further established. Combined with the analysis of the numerical stability in discrete simulation as well as the stability of the continuous system with parameter migration, a numerical algorithm that is compatible with the electromagnetic transients program (EMTP) framework is designed, as well as a C program package. The verification results on a grid-connected three-phase two-level rectifier and a two-terminal dc distribution system demonstrate that the developed tool can simulate the parameter migrations and the stimulated system dynamic process simultaneously, which can also be used to efficiently reflect the real performance of various control subsystems and their coordination in extreme cases.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Sequential Switching Shunt Regulator With Improved Controller to Suppress
           the Influence of Double-Section Phenomenon

    • Free pre-print version: Loading...

      Authors: Xiaoguang Jin;Huipin Lin;Wenxi Yao;Zhengyu Lu;
      Pages: 5318 - 5331
      Abstract: The double-section phenomenon is inherent to the sequential switching shunt regulator (S3R), which increases the bus ripple, affects the poststage filter design, generates electromagnetic interference, and reduces the system reliability. In this article, an in-depth study of the S3R reveals that the double-section phenomenon is caused by a combination of hysteresis loop overlap, sampling integration delay, and parasitic capacitance of the solar panel. To suppress the influence of the double-section phenomenon, according to the working characteristics of S3R, an improved controller is proposed: first, replace the ladder-shaped comparators with the ladder-shaped subtracters and then use fixed frequency control to fix the sampling ripple frequency; subsequently, the specific frequency of the sampling ripple is compensated to reduce the phase shift, thus reducing the delay of the sampling signal, and finally, the S3R’s double-section phenomenon is suppressed. The controller’s specific structure and parameter design procedure are also given in this article. Finally, the correctness and feasibility of the proposed method are proved by building an experimental prototype.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • An Analog-Device-Based Five-Domain Control Method and Distributed System
           Configuration for High-Power Spacecraft Power Systems

    • Free pre-print version: Loading...

      Authors: Qiqing Yang;Yahong Yang;Rui Li;Yinghua Dou;Baolei Dong;Aiwei Yang;
      Pages: 5332 - 5344
      Abstract: Deep space exploration is gaining increasing interest as the space station and lunar base projects are putting on the agenda. Due to the limited power level of the power controlling unit (PCU), high-power space power systems have to be constructed with several PCUs, forming a PCU interconnection system. However, the existing control methods and architectures are either unsuitable for systems with more than two PCUs or must be implemented with the digital controller, which is rarely used in space power systems due to the single-event upset (SEU). In this article, a communication-free distributed configuration for PCU interconnection system and a novel analog-device-based five-domain control method are proposed. Detailed control strategies and five working modes of the PCU subsystem are analyzed. Seamless switch during mode transition is realized by designing control parameters carefully, which ensures the stability of the PCU bus voltage. A three-PCU interconnection system is constructed, and both steady-state and dynamic responses of the system are tested, validating the effectiveness of the proposed control method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Hybrid Model Linearization Predictive Control for DC Bus Stabilization in
           Spacecraft Combined Power System

    • Free pre-print version: Loading...

      Authors: Cheng Qiu;Zhaoyang Li;Qifan Tan;Jing Huang;Dexin Wang;
      Pages: 5345 - 5356
      Abstract: In spacecraft, facing different loading conditions of subsystems, especially of permanent magnet synchronous motor (PMSM) system, the bus voltage has large fluctuation, which will seriously affect the power quality of the spacecraft combined power system. Therefore, it is necessary to introduce a bidirectional DC–DC converter to suppress the fluctuation of the bus voltage. Aiming at the need of controlling the bidirectional DC–DC converter, a hybrid model linearization predictive control (HMLPC) algorithm is proposed. According to the strong nonlinear hybrid characteristics of the bidirectional DC–DC converter, an optimal linear approximation model at the sampling point is established using the Jacobian matrix, based on which a piecewise affine (PWA) model is established for Buck and Boost mode, and then, a hybrid linearization predictive model is constructed. Ultimately, by introducing a two-period PWA and multistep prediction strategy, proposing a prediction error, and solving the constrained finite time optimization control (CFTOC) problem online, an optimal control law is derived. In addition, a stability analysis is provided for the proposed control algorithm. In this article, a simulative validation and a comparative analysis are presented; moreover, a combined power test platform is built to validate the proposed control algorithm. Both simulation and experiment results show that the HMLPC algorithm can effectively suppress the fluctuation of bus voltage and enhance the anti-interference ability of the system.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Gallium Nitride Efficacy for High-Reliability Forward Converters in
           Spacecraft

    • Free pre-print version: Loading...

      Authors: Aidan Phillips;Thomas Cook;Brian West;Brandon M. Grainger;
      Pages: 5357 - 5370
      Abstract: Gallium nitride (GaN) devices show particular promise for space-rated power conversion applications that rely on MOSFET technology whose performance is severely limited by the radiation hardening processes. Although the number of radiation-hardened (rad-hard) GaN devices is low, the current space-rated selection pool can still yield significant efficiency and power density improvements. However, the context of GaN research is often future-oriented such that the application of GaN to common, proven, space-rated converter designs is rare. The presented work quantifies the performance benefits of market available, space-rated GaN HEMTs over rad-hard MOSFETs for a synchronous forward converter, which remains an extremely popular topology for isolated, medium-power, dc–dc conversion on various satellite systems. Two 75-W, space-rated forward converters were designed, implemented, and benchmarked, with the power switch technology being the single variable of change. By forming Pareto-optimal fronts of the key device metrics, optimal rad-hard MOSFETs were chosen so that the baseline converter performance was considered the best case. The frequency limitations of common, available, rad-hard PWM controllers limited the power density in the GaN and Si converters alike; however, efficiency gains proved sizeable. The GaN-based converter saw a peak efficiency of 86%, which was a 4.54% improvement over the Si baseline. Detailed efficiency and loss differential plots are presented, which show the GaN converter’s reduced sensitivity to the input voltage.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Single Point Failure Free Interleaved Synchronous Buck Converter for
           Microsatellite Electrolysis Propulsion

    • Free pre-print version: Loading...

      Authors: Cristian Torres;José M. Blanes;Ausiàs Garrigós;David Marroquí;José A. Carrasco;
      Pages: 5371 - 5380
      Abstract: This article describes the design and implementation of a dc–dc converter used to power a microsatellite on-board electrolyzer. The proposed topology is a four-phase interleaved synchronous buck converter with output current control. The proposed converter is single point failure free (SPFF), so in case of any individual component failure, the functionality of the system is not compromised. SPFF operation is achieved using individual protections in each buck phase, redundant output current control, and redundant clock systems. Besides, analog majority voter circuits are used to select the correct control signal after any failure and to isolate it. Detailed mathematical analysis and circuit design are presented. Furthermore, a 40-W prototype has been implemented to validate the concept. Experimental results presented show the correct performance of the system in every case and its fault tolerant capability. In addition, the ac behavior and stability of the system have been studied and verified under the full range of possible operating conditions. Finally, efficiency measurements are presented.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Novel Power Processing Unit (PPU) System Architecture Based on HFAC Bus
           for Electric Propulsion Spacecraft

    • Free pre-print version: Loading...

      Authors: Mingzhu Fang;Donglai Zhang;Xianbin Qi;
      Pages: 5381 - 5391
      Abstract: This article proposes a novel power processing unit (PPU) system architecture based on the high-frequency alternating current (HFAC) bus for electric propulsion spacecraft. The proposed PPU system architecture takes the HFAC output of the inverter network in the main load power supply as the bus while supplying power for other low-power supplies. Compared with the conventional PPU system architecture, the number of transistors is significantly reduced, and the outputs of low-power supplies are regulated with nonisolated controllers, leading to a lower cost, more compact size, and higher reliability. Moreover, the redundancy design and the fault mode analysis are introduced, which greatly improve the flexibility of the fault operation strategies. Finally, the test on the electrical characteristic of the HFAC bus in the experimental prototype proves the feasibility and stability of the proposed system architecture. The obvious performance enhancement is further demonstrated through a systematic comparison with the conventional PPU system architecture.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Two-Stage Factorized Power Architecture DC–DC Converter for Spacecraft
           Secondary Power Supply System

    • Free pre-print version: Loading...

      Authors: Lei Wang;Donglai Zhang;Yungang Yang;Hongzhu Li;
      Pages: 5392 - 5413
      Abstract: In this article, we propose a two-stage factorized power architecture (FPA) dc–dc converter, which caters to applications that require high efficiency, high power density, low ripple, and high dynamic response of space-borne low-voltage and high-current power supply. The first-stage 48 V intermediate bus converter (IBC) adopts the six-phase interleaving magnetic integration buck converter (IMIBC). A new array high symmetry multi-phase coupled inductor (CI) is constructed, and a general zero-voltage switching (ZVS) control strategy is proposed. The designed IBC provides 2.4 kW power with a density of up to 1400 W/in3 and efficiency up to 97.15%. The second-stage point of load converter (POLC) adopts the four-phase interleaving magnetic integration LLC dc/dc transformer (DCX). A new method of current sharing, which is based on the inverse coupling resonant inductor, is proposed. This method yields good current sharing under a 15% mismatch of resonance parameters. A highly symmetrical four-phase resonant CI and a four-phase magnetic integration transformer are developed; the design of magnetic components is optimized by constructing a high-precision magnetic circuit mode. The designed POLC has a power density of up to 700 W/in3 and an efficiency of up to 97.1%. Finally, the experimental prototype is fully tested against a similar type of Vicor’s products. According to the results, the power supply designed in this article has several benefits with regard to efficiency, power density, transient response speed, and ripple.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Design Space of Sub-Resonant Frequency- Controlled
           Series–Series-Compensated Inductive Wireless Power Transfer Links
           Operating With Constant Output Current Under Frequency Constraints

    • Free pre-print version: Loading...

      Authors: Andrey Vulfovich;Alon Kuperman;
      Pages: 5414 - 5422
      Abstract: Output current of inductive wireless power transfer links (IWPTLs) with battery loads is influenced by coupling coefficient and input–output voltage. To regulate the output current while keeping the operational frequency near resonance, dc–dc converters are often added at IWPTL input and/or output, increasing system complexity and dimensions while reducing lifetime and reliability. On the other hand, a sub-resonant frequency control method was shown to eliminate the need for dc–dc converters addition as well as preventing IWPTL overrating. The technique is based on imposing bifurcation (or frequency splitting) and varying the operational frequency within certain region below resonance to regulate IWPTL output current. Due to the fact that some applications restrict the operational frequency band, methodology for deriving the design space of sub-resonant frequency-controlled series–series (SS)-compensated IWPTL (SS-IWPTL) operating under frequency constraints with constant current (CC) output is proposed in this work. The algorithm identifies all feasible combinations of loosely coupled transformer (LCT) coils self-inductances and coupling coefficients for expected ranges of input–output voltages and prescribed operational frequency band, allowing to maintain CC output. Simulations and experiments are carried out to verify the proposed methodology.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • High-Precision Composite Control Based on Dual-Sampling-Rate Extended
           State Observer for Ultra-Low Speed Gimbal Servo System

    • Free pre-print version: Loading...

      Authors: Haitao Li;Ying Wang;Bangcheng Han;Xiangwen Chen;
      Pages: 5423 - 5434
      Abstract: This article aims to deal with the speed control performance of the gimbal servo system at ultra-low speed to guarantee the accuracy of the output torque of the control moment gyroscope (CMG). The main factors leading to the speed fluctuation of the gimbal servo system are the speed measurement error and disturbance torque. This article proposes a composite controller that consists of the dual-sampling-rate reduced-order extended state observer (DSRESO) and sliding-mode controller (SMC) in the speed loop so as to improve the speed control performance at ultra-low speed. DSRESO is designed to deal with the speed measurement as well as the disturbance estimation in ultra-low speed conditions. Then, the SMC-based DSRESO is applied for speed closed-loop control so as to suppress the speed fluctuation of the gimbal servo system under ultra-low speed and disturbance torque conditions. The feasibility and effectiveness of the proposed control scheme have been verified by the simulations and experiments compared with other methods. Also, the resultant effect is that the speed tracking precision of the gimbal servo system at ultra-low speed is improved significantly.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Hybrid Two-Stage Control Solution for Six-Phase PMSM Motor With Improved
           Performance

    • Free pre-print version: Loading...

      Authors: Yixiao Luo;Xiaodong Zhang;Shuangxia Niu;
      Pages: 5435 - 5445
      Abstract: This article proposes a hybrid two-stage control solution for a six-phase permanent magnet synchronous machine (PMSM) motor with enhanced control performance. The original direct torque control (DTC) and model predictive control (MPC) are artfully integrated together to alleviate the computational burden and the harmonic currents. The proposed method is implemented in two steps. First, the original DTC method is adopted to determine the orientation vector from six existing vectors. It is worthy to mention that the orientation vector is different from the commonly used reference vector calculated through the deadbeat control theory. Second, the prediction vectors located in the same sector with the orientation vector will be evaluated in the original MPC manner. In this way, the enumeration of all the prediction vectors is avoided and the computational burden is avoided. In addition, discrete duty ratios are assigned to define other two groups of virtual vectors to enhance the current quality. In this way, high-performance control of a six-phase motor can be achieved by simply combining the standard DTC and MPC control structure. Experimental results have been used to assess the goodness of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Quantitative Modeling and Analysis of Switching Oscillations of Cascode
           GaN Devices in Half-Bridge Converters

    • Free pre-print version: Loading...

      Authors: Bin Luo;Guangzhao Luo;Sihai Li;
      Pages: 5446 - 5463
      Abstract: Having high efficiency and power density, the motor drives based on wide bandgap (WBG) devices can better meet the requirements for developing more electric aircraft (MEA). However, the fast switching characteristic of gallium nitride (GaN) devices has led to undesirable voltage and current oscillations during turn-ON and turn-OFF processes, thus decreasing the reliability of the electric drive system. The complicated structure of cascode GaN devices and various parasitic parameters in the device and the half-bridge converter make the switching oscillation modeling of cascode GaN device comparatively complex. In this article, an equivalent circuit approach in consideration of nonlinear characteristics in voltage-dependent junction capacitances is presented to model the switching oscillation for high-voltage (650 V) cascode GaN-based half-bridge converters. Quantitative mathematical models are derived to provide a theoretical analysis of the switching oscillation for turn-on and turn-off processes of cascode GaN devices. Furthermore, the influences of device and circuit parameters on the oscillation are investigated in detail, offering a reliable guidance to the gate driver and print circuit board design. Finally, experimental studies on the basis of cascode GaN and custom cascodes are carried out to validate the modeling approach. The results have proved that one of the root causes of the oscillations is how the different parasitics interact.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Latching Current Limiter for Space Platform Power Distribution Using a
           Low-Voltage p-MOSFET and a Normally-ON SiC JFET

    • Free pre-print version: Loading...

      Authors: A. Garrigós;D. Marroquí;C. Orts;C. Torres;J. M. Blanes;
      Pages: 5464 - 5473
      Abstract: Power distribution using latching current limiters (LCLs) [also known as solid-state power controllers (SSPCs)] is very common for 28- and 50-V bus voltage distribution on European satellite platforms. However, 100-V and even higher voltage distribution platforms generally do not employ the same approach as lower bus voltage platforms since the commonly employed p-MOSFET devices are not well suited for such voltage levels. This work introduces an LCL for 100-V distribution units using a composite power device consisting of a low-voltage p-MOSFET device and a high-voltage, normally-ON silicon carbide junction field effect transistor (SiC JFET). The description of the circuit and the experimental validation using a hypothetical class-2 (2.2–2.8 A), 100-V, LCL is discussed. In addition, in this work, two interesting characteristics are also proposed and validated, and automatic control of the tripping time depending on the overload severity and soft starts for capacitive inrush currents. Robustness and fast reaction, less than 500 ns under short-circuit conditions, have been demonstrated, as well as tight current regulation during overload faults.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Circuit Proposal of a Latching Current Limiter for Space Applications
           Based on a SiC N-MOSFET

    • Free pre-print version: Loading...

      Authors: Abraham López;Pablo Fernández Miaja;Manuel Arias;Arturo Fernández;
      Pages: 5474 - 5485
      Abstract: Latching current limiters (LCLs) provide individual overcurrent protection to payloads protecting the satellite power bus. Under an overload, they limit the maximum current for a certain time. After this time, if the failure persists, the LCL isolates it from the power bus. The keystone of the LCLs is the current-limiting transistor. In traditional LCL designs, P-MOSFETs are used as the main current-limiting device. However, in this work, a complete LCL based on N-MOSFETs is presented. This change involves a complete redesign of the control circuitry of the LCL architecture. The use of silicon carbide (SiC) is explored to assess the possibility of operating at higher voltages and potentially at higher temperatures. This article shows a complete LCL design based on a SiC N-MOSFET. The design is tested implementing a class 10 LCL (10 A as nominal current) for a bus voltage of 100 V, a limitation current of 12 A, and a limitation time (trip-OFF time) of 1.5 ms.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Modular Bidirectional Solid-State DC Circuit Breaker for Next-Generation
           Electric Aircrafts

    • Free pre-print version: Loading...

      Authors: I. Venkata Raghavendra;Satish Naik Banavath;C. N. Muhammed Ajmal;Anindya Ray;
      Pages: 5486 - 5497
      Abstract: The design of electric power systems (EPSs) for the aviation industry has become a major research area to reduce the global annual CO2 emission caused by the transportation sector. DC power distribution is envisaged to meet the high load demand of more-electric and all-electric aircraft power architectures. Nonetheless, the development of dc distribution is significantly impeded by the challenges associated with dc system protection. Aircraft EPS demands high speed and high current protection. Among various dc circuit breaker (DCCB) technologies, solid-state dc circuit breakers (SSCBs) operate at higher speeds. To make them withstand high current ratings, modular structured DCCBs with the highest power density, reliability, and bidirectional fault interruption capability are presented in this article. The existing DCCBs fail to comply with the design constraints such as faster response, high current breaking, and compact design. This article proposes a coupled inductor-based modular bidirectional SSCB that employs the magnetic coupling principle for counter-current commutation of thyristors. The proposed modular SSCB exhibits a fast fault interruption time of approximately 200 $mu text{s}$ . The analysis, design, and experimental validation of the proposed SSCB are presented in detail. Each module in the prototype is designed for a system rating of 270 V/15 A. The performance of this SSCB for single- and two-module operations is experimentally verified for a 270-V/20-A dc system.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Development of High-Power Bidirectional DC Solid-State Power Controller
           for Aircraft Applications

    • Free pre-print version: Loading...

      Authors: Zhou Dong;Ren Ren;Fei Wang;
      Pages: 5498 - 5508
      Abstract: The high-power solid-state power controller (SSPC) will be a critical component for the future electrified aircraft propulsion system. This article presents the development of a 1 kV 500 A bidirectional dc SSPC using SiC power modules and transient voltage suppression (TVS) diodes. The design procedure and implementation of the SSPC are presented in detail and the system level influence is discussed. Due to the limited power of a single switch, parallel and/or series connections of switches are necessary for high-power SSPCs, and the corresponding challenges are investigated with possible solutions. In addition, the high peak-to-average clamping voltage ratio caused by Ldi/dt of the turn-off current commutation and foldback characteristics of high-power TVS diodes is addressed. Finally, the testing setups for the high-power SSPC are presented, and all key functions are tested for the SSPC. The power rating and the specific power of the developed SSPC are superior to state-of-the-art counterparts to show the advantage of the developed one.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Distributed Price-Based Power Management for Multibuses DC Nanogrids EEMS

    • Free pre-print version: Loading...

      Authors: Edivan Laercio Carvalho;Lucas V. Bellinaso;Rafael Cardoso;Leandro Michels;
      Pages: 5509 - 5521
      Abstract: Nanogrids for single consumers have gained importance based on the development of standards for prosumers’ electrical installations (PEIs) such as the IEC 60364 series. All distributed energy resources (DERs) are usually integrated into a single place using one or more dc buses to reduce power conversion losses in those systems. Also, an electrical energy management system (EEMS) is required for the nanogrids smart operation, where droop controls and state machines have been considered for power management. The drawback of these strategies is that the power management is poor when droop controls are considered at the second layer because all DERs must contribute to the dc bus voltage regulation. In addition, the state machines are limited due to their reduced flexibility. The main contribution of this article is a distributed price-based power management (d-PBPM) proposed to overcome these challenges. The d-PBPM is based on dc bus signaling and the price theory, and no droop control is required in the second layer, improving the management efficiency. Experimental results show that the d-PBPM makes the nanogrids’ EEMS scalable to new DERs and new dc buses, considering the addition of distributed sources, dc buses, and energy price to an existing nanogrid. The experimental setup includes a dual dc bus nanogrid with photovoltaic (PV) systems, energy storage, loads management, and ac grid interface.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Boost Converter Control of PV System Using Sliding Mode Control With
           Integrative Sliding Surface

    • Free pre-print version: Loading...

      Authors: Roberto Sussumu Inomoto;José Roberto Boffino de Almeida Monteiro;Alfeu J. Sguarezi Filho;
      Pages: 5522 - 5530
      Abstract: Maximum power point tracking (MPPT) is a technique to find the maximum power from a photovoltaic (PV) system, however, in fast variation environment conditions it loses performance. This article proposes a sliding mode (SM) controller applied to the dc–dc boost converter of a PV system to improve performance. The proposed controller consists of two control loops: input voltage control loop oriented by MPPT algorithm to calculate the inductor current; and current control loop to calculate the duty cycle of the frequency switch. Experimental results using a solar kit are presented to verify its performance and results are compared with lead-lag and SM plus proportional–integral (SMPI) controllers showing a reduction of steady-state error, overshoot, and settling time.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Simple Closed-Loop Test Based Control of Boost Converter Using Internal
           Model Control and Direct Synthesis Approach

    • Free pre-print version: Loading...

      Authors: Kartikesh Kumar Jha;Md Nishat Anwar;Badini Sai Shiva;Vimlesh Verma;
      Pages: 5531 - 5540
      Abstract: In this article, a simple controller design method for output voltage control of dc–dc boost converter (BC) has been proposed. A simple closed-loop step test with proportional gain $k_{0}$ is performed. BC open-loop transfer function is obtained from the closed-loop step response test data, which does not require information of BC circuit parameters. Furthermore, the controller is designed from the open-loop model of the BC through the internal model control (IMC) scheme and direct synthesis (DS) approach. The robust stability analysis of both the control schemes has been carried out. The proposed modeling technique and controller design methods have been validated in the experimental setup. Both the controller design techniques work satisfactorily. Superior transient performance of the IMC scheme in comparison to the DS scheme has been observed.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Novel Fault-Tolerant Operation Approach for the Modular Multilevel
           Converter-Based STATCOM With the Enhanced Operation Capability

    • Free pre-print version: Loading...

      Authors: Yu Jin;Qian Xiao;Josep Pou;Hongjie Jia;Yanchao Ji;Remus Teodorescu;Frede Blaabjerg;
      Pages: 5541 - 5552
      Abstract: The operation capability of the modular multilevel converter (MMC)-based static synchronous compensator (STATCOM) is limited under submodule (SM) failures. When running in the STATCOM mode, the floating dc-link voltage of the MMC is adjustable. Therefore, this article proposes a novel fault-tolerant operation approach to enhance the operation capability of the MMC under severe SM failures. First, the dc-link voltage is dynamically regulated under SM failures, where the capacitor voltages of all SMs are slightly increased. The modulation ranges of the faulty and healthy phases can be enlarged, and the even voltage stress distribution can be realized. Then, a low-magnitude fundamental frequency zero-sequence voltage (FF-ZSV) is injected to balance the line-to-line voltages. Finally, the virtual energy idea is proposed, where the capacitor voltages of faulty SMs are considered to be clamped at the reference value. As a result, the arm energy reference will be the same in all six arms, and the arm energy balancing control is simplified. Detailed comparisons show that the proposed approach has an enhanced operation capability with lower capacitor voltage increment. Simulation and experimental results verify that even under severe SM failures, the proposed approach can still guarantee the fault-tolerant operation within the specified security region.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • An Embedded Communication Method for In-Home Energy Routers With
           Power/Signal Dual Modulation

    • Free pre-print version: Loading...

      Authors: Ruichi Wang;Guipeng Chen;Jinghui Chen;Jiande Wu;Wuhua Li;Shuye Ding;Zhengyu Lin;Xiangning He;
      Pages: 5553 - 5563
      Abstract: This article proposes a novel embedded communication strategy for in-home energy routers (IHERs). It is based on the power/signal dual modulation (PSDM) principle and applied in the small-scale community energy local area network (E-LAN). The proposed communication strategy multiplexes power converters as data transmitters, and thus high cooperation and synchronization between power flow and information flow are achieved. In addition, system reliability is enhanced since communication module has practically the same reliability as the power module. A typical IHER’s structure and operation principles are presented, based on which the detailed design of embedded communication is proposed. For distributed power management of community E-LAN, both intra-IHER communication and inter-IHERs communication are involved, and their channels are modeled mathematically. IHER interconnection interface converters (IICs) play a significant role in power exchange between IHERs, and their operation modes are analyzed in detail. Finally, an experimental prototype is built to validate the feasibility of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Chirp Signal Injection Method and Real-Time Impedance Characteristic
           Measurement of Electric Energy Router

    • Free pre-print version: Loading...

      Authors: Xing Weng;Zhengming Zhao;Kainan Chen;Liqiang Yuan;
      Pages: 5564 - 5577
      Abstract: The plug-and-play capability of electric energy router (EER) is a hot topic in recent years, and the impedance measurement is one of the key technologies in the field of stability estimation for plug-and-play. In this article, EER injects a small chirp signal to the dc equipment and measures the corresponding response signal, thereby calculating its impedance characteristic in real time. Since the conventional control method of dc port is difficult to superimpose high-frequency perturbing signal on the power components, a closed-loop control method for injecting chirp signal is proposed, based on the modulation–demodulation process in communication principles. In addition, an impedance measurement method using short-time Fourier transform (STFT) is proposed, which splits the time-consuming Fourier transform to the same time as sampling. A 10-kW noninverting buck–boost (NIBB) converter was built as the dc/dc stage of EER to verify the above methods. The experimental results show that the chirp signal can be injected well using the proposed methods. Also, the impedance can be accurately measured within 2 s.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Model Predictive Duty Cycle Control for Three-Phase Vienna Rectifiers With
           Reduced Neutral-Point Voltage Ripple Under Unbalanced DC Links

    • Free pre-print version: Loading...

      Authors: Bo Xu;Kaipei Liu;Xiaohong Ran;Qing Huai;Shiqi Yang;
      Pages: 5578 - 5590
      Abstract: Under unbalanced dc links, the control of a three-phase Vienna rectifier is challenging. To deal with the unbalanced dc links, the optimal switching sequence model predictive control (MPC) regulates the neutral-point (NP) voltage through preselecting a redundant vector and grid current by reconstructing duty cycles of the optimal switching sequence. However, its one-redundant-vector-per-control-interval characteristic leads to large NP voltage ripple. To solve this problem, in this article, a model predictive duty cycle control method is proposed for three-phase Vienna rectifiers under unbalanced dc links. First, we study the impacts of duty cycles on the variations of instantaneous current, and then, the three-phase duty cycles are derived by predefined objective function minimization. Second, considering both the operational characteristics and unbalanced dc links of the Vienna rectifier, a new modification method for duty cycles is presented. This method ensures the grid current quality and decouples the control of grid current and NP voltage. Finally, an MPC-based NP voltage control strategy is proposed to reduce the NP voltage ripple. Experimental results demonstrate that the presented method can effectively reduce the NP voltage ripple.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Model Predictive Control for Grid-Connected Current-Source Converter With
           Enhanced Robustness and Grid-Current Feedback Only

    • Free pre-print version: Loading...

      Authors: Cheng Xue;Li Ding;Xuesong Wu;Yunwei Li;Wensheng Song;
      Pages: 5591 - 5603
      Abstract: The current-source converter (CSC) features the second-order characteristic, and multivariable feedback is necessary to suppress the filter resonance. Model predictive control (MPC) has shown advantages in terms of the multiple-input–multiple-output (MIMO) system. This article contributes to the MPC scheme applied to CSC from two aspects. First, based on the typical one-step prediction, existing MPC with both grid-current and capacitor voltage feedback has been applied to mitigate the resonance issue but lacks the investigation and improvement of system robustness to parameter mismatch, especially in such a second-order system. Thus, the dual-disturbance observer is proposed, where both the additional capacitor voltage reference and the lumped input disturbance caused by parameter mismatch are estimated online. As a result, the grid-current reference tracking performance can be improved under mismatched parameters. Second, to reveal the resonance principle with different state feedback types, the tracking process of the grid current is intuitively analyzed in the time domain. The MPC scheme is further assessed by increasing the prediction horizon length, and the results show that the CSC can work well with only gird-current feedback. In this case, both the weighting factor and corresponding reference estimation for the capacitor voltage can be avoided, thus significantly simplifying the design stage and reducing the effect caused by the parameter mismatch. Experimental results verify the effectiveness of the proposed scheme and perspectives.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Neutral Point Voltage Balancing Control Based on Adjusting Application
           Times of Redundant Vectors for Three-Level NPC Inverter

    • Free pre-print version: Loading...

      Authors: Abdelmalik Zorig;Said Barkat;Ariya Sangwongwanich;
      Pages: 5604 - 5613
      Abstract: Three-level neutral-point-clamped (NPC) inverter is used in many industrial applications due to its attractive advantages in terms of harmonics content, achieved power level, and electromagnetic interference reduction. However, the main concern in this topology is the imbalance of the neutral point (NP) voltage in the dc side of the inverter. Indeed, the NP voltage distorts the output voltage of the inverter and increases voltage stress on its switching devices. In this article, a new NP voltage balancing control based on modified three-level space vector pulse width modulation (SVPWM) is proposed. The core idea of this method consists in adjusting the application times of redundant vectors in such a way that the NP voltage is kept balanced. In this method, the appropriate adjustment direction is determined by measuring only the capacitor voltages and the output currents of the inverter. The performances of the proposed method are validated and compared through various experimental tests, and the obtained results show an excellent NP voltage balancing regardless of the modulation index values.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Photovoltaic Energy Conversion System Integrated Into Unbalanced
           Distribution Electrical Networks Through Hardware in the Loop

    • Free pre-print version: Loading...

      Authors: Sergio Fernando Rodríguez-Contreras;Nadia Maria Salgado-Herrera;Miguel Robles;Juan Ramon Rodríguez-Rodríguez;Nestor Gonzalez-Cabrera;Mario Alberto Santoyo-Anaya;
      Pages: 5614 - 5625
      Abstract: In this article, a real-time, hardware in the loop (HIL) and experimental photovoltaic energy conversion system (PVECS) integrated into unbalanced distribution electrical networks is presented. Commonly, the three-phase voltages are not balanced, because the input–output of single-phase loads in low and medium voltage networks. In this context, the photovoltaic (PV) systems integration under the dq0-Frame control operation scheme, tend to generate current deformations. In contrast, a new control technique for PVECS interconnection is validated in a HIL scheme, even in the presence of unbalanced voltage. This new technique is considered simple and easy to implement, since it consists of a single PI control loop, guaranteeing reliable operation under unbalances voltage events. Thus, preserving favorable characteristics, such as: 1) always balanced currents; 2) low harmonic distortion; 3) unit power factor; and 4) Compliance with the rules of the network code. The PVECS effectiveness is assessed by complete mathematical model, the simulation results are evaluated using MATLAB-Simulink (MATLAB r2018, Mathworks, Natick, MA, USA), and the experimental results are validated with a small-scale prototype operating in a HIL environment and the real-time simulator Opal-RT Technologies (Montreal, QC, Canada); integrating a power capacity of 15 kW in distribution networks.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • An Algorithm for Estimation of Stator Resistance and Inductance of
           Low-Cost SMPMSM Drives

    • Free pre-print version: Loading...

      Authors: Anton Dianov;
      Pages: 5626 - 5634
      Abstract: The information on stator resistance and inductance is extremely important for advanced electrical drives, which are used for tuning of position estimators, current controllers, temperature monitoring, and so on. The properly tuned control systems can provide fast response, have higher stability, and increase the efficiency of motor drives; as a result, it is of great importance at the development and tuning stages. This article proposes a simple estimation technique for surface-mounted permanent magnet synchronous motors (SMPMSMs), capable of measuring stator resistance and inductance. In order to measure the stator resistance, the developed algorithm injects two-leveled dc currents that provide information for resistance calculation. At the next stage, the estimation algorithm initiates exponential current transient, measures electric time constant of the motor, and calculates inductance. In contradiction to the conventional approach, this work composes a more detailed model of the motor and takes inverter voltage drop into account. Furthermore, this article studies several exponential transients, compares them to each other, and provides recommendations for use of each approach. Then, the proposed ideas are verified using several motors of different powers and parameters. Finally, the recommendations on application of each approach and parameter selection are provided.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Predictive Current Control and Field-Weakening Operation of SPMSM Drives
           Without Motor Parameters and DC Voltage

    • Free pre-print version: Loading...

      Authors: Haitao Yang;Yongchang Zhang;Wenjia Shen;
      Pages: 5635 - 5646
      Abstract: The prior model-parameter-free predictive current control (MFPCC) applies a 1-D lookup table (1-D LUT) to store current variation, where the index input is the number of the basic voltage vector. However, current variation is not only related to the input voltage but also depends on the rotor position. As the influence of rotor position is not considered in the prior MFPCC, high current spikes may occur during normal operation. Aiming to improve the steady-state performance, the proposed MFPCC utilizes a 2-D LUT to backup current variations, where the second-dimensional input is the discretized rotor position. The proposed method keeps good robustness and eliminates current spikes in the prior MFPCC. Moreover, a field-weakening (FW) method is developed to extend the speed range. As no modulator is employed in MFPCC and only discrete voltage vectors are available, the conventional voltage magnitude-based FW control scheme cannot be directly applied. To address such issue, a complex-coefficient filter is employed to calculate the modulation index of the fundamental voltage, which is then fed to the FW controller to generate demagnetizing current. The proposed MFPCC can achieve satisfactory performance without motor parameters and the measurement of dc voltage. Experimental results confirm the effectiveness of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Novel Framework of Extended Active Power and Its Application Into Low
           Complexity MPC for Enhanced Steady-State Performance

    • Free pre-print version: Loading...

      Authors: Xiaohong Ran;Bo Xu;Kaipei Liu;
      Pages: 5647 - 5658
      Abstract: This article proposes a novel low complexity model predictive control (LC-MPC) for the performance improvement of the ac/dc converter under unbalanced grid voltages. Although the finite control set model predictive control (FCS-MPC) is a very effective control method, whose cost function is evaluated for all discrete switching states, presenting a high calculation burden for the efficient control. To obtain a reduced harmonic of the grid current and a low calculation burden under unbalanced grid conditions, a new framework of the extended active power is proposed and a negative conjugate of new complex power is chosen as a control variable. In the proposed LC-MPC method, the best voltage vector is obtained with only one prediction whether it is the proposed single-vector-based LC-MPC (SVLC-MPC) or double-vector-based LC-MPC (DVLC-MPC) method, and the optimal duration time using the framework of the extended active power is derived in detail based on the principle of minimizing the error of the new complex power. The proposed LC-MPC has a similar dynamic performance with the prior model predictive control (MPC) methods and obtains much better steady-state performance, i.e., the reduced harmonics of grid currents, under severely unbalanced grid voltages. The comparative experiments confirm the effectiveness of the proposed LC-MPC method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Coupling Effect Analysis and Design Principle of Repetitive Control Based
           Hybrid Controller for SVG With Enhanced Harmonic Current Mitigation

    • Free pre-print version: Loading...

      Authors: Lintao Ren;Fei Wang;Yunjie Shi;Luwang Gao;
      Pages: 5659 - 5669
      Abstract: Static var generator (SVG) is mostly utilized under polluted grid conditions with certain power quality problems, of which the grid disturbance will lead to the distortion of grid-side current. Hybrid repetitive controller (RC), as an effective method to suppress periodic distortion of grid-connected converters and to improve the dynamic response of conventional RC, has been adopted in existing approaches. However, the physical meaning of existing modeling based on the small gain theorem is not clear. Besides, the conventional design method is difficult to reveal the stability domain and to obtain an optimized repetitive gain, which influences the anti-disturbance performance. In this article, the coupling effect among the controllers of hybrid RC is revealed, showing clear physical meaning, thus the mechanism resulting in the instability problem and delay effect is addressed clearly. Different from existing methods, a simpler design principle is proposed, and a universal stability domain analysis for hybrid RC can be directly obtained and ensure a maximized repetitive gain. A proportional, resonant, and RC (PR-RC) is given as an example to improve the dynamic response of the SVG under $a$ – $b$ – $c$ coordinate. Experimental results demonstrate the correctness and effectiveness of the coupling analysis and parameter design.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Negative Sequence Control for Virtual Synchronous Machines Under
           Unbalanced Conditions

    • Free pre-print version: Loading...

      Authors: Eros B. Avdiaj;Salvatore D’Arco;Luigi Piegari;Jon Are Suul;
      Pages: 5670 - 5685
      Abstract: In this article, five strategies for controlling the negative sequence currents of a virtual synchronous machine (VSM) under unbalanced conditions are comparatively assessed, considering both grid-connected and islanded operations. While these strategies have been individually proposed in recent literature, their characteristics and performance have not been systematically evaluated. Thus, a VSM structure serving as a basis for comparing the different strategies is presented in detail, with modifications for preventing double frequency power oscillations from influencing the virtual swing equation and the inertial dynamics. The active and reactive power oscillations, and the power transfer capability within the converter current limitation, are theoretically derived as a function of the unbalances in the local voltage. Simulation results and experimental validation on a 50-kVA modular multilevel converter (MMC) prototype with 12 sub-modules per arm demonstrate the validity of the theoretical analysis. The presented results serve as the basis for evaluating the applicability of the studied control strategies under different operating conditions.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • An SMC-ESO-Based Distortion Voltage Compensation Strategy for PWM VSI of
           PMSM

    • Free pre-print version: Loading...

      Authors: Xue Hao;Yutao Luo;
      Pages: 5686 - 5697
      Abstract: The nonlinear factors of the voltage source inverter (VSI) lead to an error between the reference voltage and output voltage, which causes the voltage and current distortion and torque fluctuation. It is necessary to reduce its impact on the fields, such as parameter identification, sensorless control, and motor drives. Thus, a distortion voltage compensation strategy based on sliding mode control (SMC) and extended state observer (ESO) is proposed in this article. First, inverter nonlinearity factors (INFs), such as the dead time of the inverter, the switching delay, and the voltage drop of the switching tube and the diode, are analyzed, and the theoretical compensation voltage is obtained with reference to the nominal parameters. Then, an ESO considering the theoretical compensation voltages is employed to observe the distortion voltage online caused by INF and motor parameters perturbations under different operating conditions. In addition, the SMC is used to improve the dynamic compensation effects of the system. The Lyapunov theory demonstrates stability. Finally, the proposed method is validated by a VSI feeding a surface permanent magnet synchronous motor (SPMSM) without an additional hardware circuit. Simulation and experimental results prove the advantages of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • An MMC DC-Link Voltage Control Method Without Actual Voltage Measurement

    • Free pre-print version: Loading...

      Authors: Shuguang Song;Jinjun Liu;Xingxing Chen;
      Pages: 5698 - 5708
      Abstract: DC-link voltage control is of great importance for modular multilevel converter (MMC)-based high-voltage direct-current (HVDC) systems. Existing methods need to measure the actual dc-link voltage, which are referred to as direct control methods in this article and require a reliable dc voltage measuring device. The measurement system is complicated. Also, once malfunction occurs, dc-link voltage control may fail. This article aims to develop a dc-link voltage control method without actual voltage measurement. The idea is based on the coupling effect between dc-link voltage and submodule (SM) capacitor voltage. Based on the analysis, an indirect dc-link voltage control method is proposed. In this method, the existing dc-link voltage control loop is first replaced by the total capacitor voltage regulation control loop. Then, a compensation signal is introduced to the switching functions to mitigate undesired voltage deviation. Two approaches are proposed to generate a proper compensation signal. The proposed method can be integrated into the existing MMC control system. Also, in measurement failure cases, it can come into service and continue maintaining MMC dc-link voltage, improving system reliability. Both simulation and experimental results confirm the validity and effectiveness of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Self-Tuning Adaptive Control Scheme for a Grid-Connected Three-Phase PV
           System

    • Free pre-print version: Loading...

      Authors: Malay Bhunia;Bidyadhar Subudhi;
      Pages: 5709 - 5716
      Abstract: This article presents a new self-tuning sinusoidal recursive controller (STSRC) for handling the uncertainties and disturbances in a three-phase grid-connected photovoltaic system (GCPVS). The performance of a GCPVS is greatly influenced by the uncertainties, such as intermittency in solar irradiation, change in capacitance and equivalent series resistance (ESR) of dc-link capacitor, and variation of impedance between the inverter and the grid. This STSRC comprises improved linear sinusoidal tracer-based recursive least-square estimation (IRLS) to achieve robust performances, despite the parametric uncertainties through real-time estimation of its parameters, and updation of its gains. The efficacy of the proposed STSRC is verified through simulation using MATLAB/Simulink and experimental studies pursued on a 2.5-kW prototype. It is observed that STSRC exhibits superior tracking of PV voltage with reduced ripple and improved grid current with reduced total harmonic distortion (THD) of 1.66%. The estimation accuracy is found above 92%.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Flexible Energy Gateway for Hybrid Nanogrids

    • Free pre-print version: Loading...

      Authors: Yuchen Zhang;Simone Buso;Tommaso Caldognetto;
      Pages: 5717 - 5726
      Abstract: This article presents the topology and control of a three-port energy gateway (EG) for hybrid ac/dc nanogrids. The simple hardware architecture allows connecting renewable energy generators, energy storage (ES) devices, such as ultracapacitors, and the utility grid through three different interface converters, which, altogether, define the three-port EG of the nanogrid. The proposed EG represents a tradeoff between circuit complexity and controls flexibility, allowing: 1) operation of the ES port over a wide voltage range; 2) control of the local dc-bus voltage at a predefined set-point; 3) multidirectional power flow; and 4) support of the local ac-bus voltage with the possibility to transition into islanded operation. A hierarchical control strategy is presented that enables flexible power exchange between the ac and dc buses. At the top of the control hierarchy, a human–machine interface is dedicated to operation mode selection and parameter preset; then, a supervisory control layer is present for system-level monitoring and control functions; the lower layer of the hierarchy is constituted by converter control functions for power flow regulation, achieved leveraging on voltage and current controllers. The flexibility and effectiveness of the proposed EG architecture, control, and implementation are demonstrated in this article in a variety of operation modes by means of experimental results.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Passive Islanding Detection Method for Distribution Power Systems With
           Multiple Inverters

    • Free pre-print version: Loading...

      Authors: Guanhong Song;Bo Cao;Liuchen Chang;
      Pages: 5727 - 5737
      Abstract: The high penetration of grid-connected distributed energy resources (DERs) leads to a need for smart inverters to enhance their performance and minimize the negative impacts of these resources on grid behavior. However, the interconnection of these smart inverters may interfere with their anti-islanding algorithms, which creates detection difficulties. Advanced islanding detection techniques are therefore required to detect and disrupt islanding operations under such an environment with system’s disturbances and interferences. Even though various islanding detection methods have been developed in recent literature to identify islanding operations with high detection accuracy and minimized nondetection zone, these methods mainly focus on a single inverter system, which is incompatible in modern power system with high penetration of grid-connected inverters. In this article, an advanced passive islanding method is proposed for a single-phase distribution power system taking account of the interferences and disturbances brought by these grid-connected inverters. The effectiveness of the proposed passive islanding method is validated through experiments in a laboratory platform. Also, the experimental results have verified that the proposed methods can effectively terminate the islanding operation even with rich inverters’ interferences.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Research on Efficient Single-Sided Asymmetric Modulation Strategy for Dual
           Active Bridge Converters in Wide Voltage Range

    • Free pre-print version: Loading...

      Authors: Mixin Wang;Shusheng Wei;Di Mou;Peng Wu;
      Pages: 5738 - 5748
      Abstract: For the problem of narrow soft-switching range and low efficiency of dual active bridge (DAB) converter in wide voltage range, this article proposes a single-sided asymmetric duty modulation (SSADM) strategy, which contains only two control degrees of freedom, and significantly improves the soft-switching performance and efficiency at light load. First, the potential advantages of asymmetric duty modulation (ADM) method are described through waveforms. The principle of determining which full bridge to adopt the ADM is given and the working principle of SSADM is described. Second, a linear pulse logic combination analysis of SSADM in time domain is performed to establish a complete steady-state mathematical model. To solve the analytical expression for the optimal solution of SSADM, the peak-to-peak value of the inductor current with simple expression is chosen as the optimization objective, and the global optimal solution of SSADM is solved based on the Karush–Kuhn–Tucker (KKT) condition, and the voltage closed-loop control strategy of SSADM is presented. In addition, the soft-switching range of SSADM is analyzed. Finally, the experimental platform of DAB converter based on SiC device is built. Compared with other modulation strategies, SSADM shows better soft-switching performance with significant efficiency improvement, which is verified by the experimental results.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Digital Adaptive Control Method for Optimizing Valley Current of Active
           Clamp Flyback Converter

    • Free pre-print version: Loading...

      Authors: Minggang Chen;Shen Xu;Linlin Huang;Weifeng Sun;Longxing Shi;
      Pages: 5749 - 5761
      Abstract: In an active clamp flyback (ACF) converter working in critical mode (CRM), the zero-voltage switching (ZVS) of the main power switch can be realized by the negative valley current, which is related to conduction loss and switching loss. Therefore, how to control the negative valley current will affect the overall efficiency of the system. This article investigates and compares the three existing technologies and summarizes their limitations in practical applications. Therefore, a digital adaptive control method is proposed to regulate the valley current according to different working conditions. Meanwhile, small-signal analysis is performed to ensure the stability of the proposed control method. The proposed control method is verified by a field-programmable gate array (FPGA)-based 12-V, 3-A ACF, and experimental results show that the proposed theoretical model should be accurate and practical and there is an average efficiency improvement of 1.34% compared to conventional control.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Power Flow Management With Q-Learning for a Grid Integrated Photovoltaic
           and Energy Storage System

    • Free pre-print version: Loading...

      Authors: Mohammed Ali Khan;Ahteshamul Haque;V. S. Bharath Kurukuru;
      Pages: 5762 - 5772
      Abstract: This article develops a fuzzy Q-learning (FQL) approach-based power flow management algorithm for a single-phase grid-connected (GC) photovoltaic (PV) system with an energy storage unit (ESU). The FQL coordinates the PV power generation, which is based on the mission profile, the state of charge (SOC) of ESU, and the load profile such that a power balance is achieved in the network. Furthermore, the transition between standalone (SA) and GC modes during the power flow management is achieved using a proportional capacitor current feedback. While operating in the SA mode, the control action for the load voltage is achieved by an outer current loop. This combination of coordinated and transition control achieves power balance and smooth transition between the SA and GC modes. To verify the effectiveness of the proposed control strategy, a 4 – kWp PV system is operated along with an ESU in both SA and GC modes for a varying mission and load profile. The simulation and experimental results validated the multifunctional features of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Capacitor Voltage Regulation Strategy for 7-Level Single DC Source Hybrid
           Cascaded Inverter

    • Free pre-print version: Loading...

      Authors: Lei Ren;Lei Zhang;Li Wang;Shangjian Dai;
      Pages: 5773 - 5784
      Abstract: Hybrid cascaded multilevel inverters have been proved to be an important alternative in the medium-voltage applications for their high-quality output. To reduce the use of dc sources, the single dc source cascaded H-bridge (SDS-CHB) inverter with the low-voltage dc source replaced by a capacitor is employed and investigated in this article. To address the challenge of the input capacitor voltage regulation, the charge/discharge modes with carrier-based pulsewidth modulation at different operation conditions are analyzed in detail and generally for all the combinations of load current magnitude and power factor from −1 to 1. The stability conditions for capacitor voltage control are analytically derived. Based on the analysis, a simple but effective capacitor voltage regulation strategy and an operation parameter optimization method are proposed. Within the identified stable operation regions, the proposed control strategy can keep the input capacitor voltage at the desired voltage level, i.e., half of the high-voltage cell dc source meanwhile can ensure the inverter high-quality output. The proposed operation parameter optimization method can minimize the output filter capacitor with good output. The capacitor voltage regulation strategy and operation parameter optimization method have been successfully substantiated by the simulation and experimental results of a seven-level hybrid cascaded inverter.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Multiscalar Model-Based Predictive Torque Control Without Weighting
           Factors and Current Sensors for Induction Motor Drives

    • Free pre-print version: Loading...

      Authors: Anxin Yang;Ziguang Lu;
      Pages: 5785 - 5797
      Abstract: This article focuses on eliminating the weighting factor in traditional predictive torque control (PTC) and considers the control scheme without current sensors. A current sensorless direct PTC method without the weighting factor for induction motor (IM) drives is proposed. Based on the multiscalar model, the controller directly predicts the torque and its dual quantity, instead of predicting the stator flux and stator current in advance and then indirectly calculating the torque like PTC. Since the torque and its dual quantity (the inner and external products of the flux and stator current) have the same units and dimensions, the design of the cost function does not require a weighting factor. Furthermore, an adaptive virtual current observer is used to reconstruct the stator currents. The estimated currents replace the measured currents to realize current sensorless, which can avoid the measurement noise caused by the current sensors, thus reducing the current and torque ripples. Simulation and experimental results illustrate the effectiveness of the proposed approach under different working conditions.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • An Algorithm for Offline Measurement of Motor Stator Resistance and
           Voltage Drop Across Inverter Switches for Washing Machine Drives

    • Free pre-print version: Loading...

      Authors: Anton Dianov;
      Pages: 5798 - 5808
      Abstract: The knowledge of the exact value of motor phase resistance is extremely important for modern electrical drives, which use it for tuning of current controllers, position estimators, temperature monitoring, and so on. At the same time, the value of voltage drop across inverter switches is necessary for providing proper and efficient control, especially in the low-speed region, where the impact of system nonlinearities is significant. This article proposes a novel algorithm for the offline measurement of motor resistance and voltage drop across inverter switches, which significantly improved the performance of washing machines in open-loop starting and low-speed operation. The proposed technique uses two step injection of dc current into stator windings, which provides data for the estimation of resistance and voltage drop. This article describes traps and pitfalls on the way of implementation and tuning and provides recommendations on avoiding them. After analysis of detailed experimental results, the author gives recommendation on a selection of algorithm parameters in order to provide low estimation errors. Following successful implementation and a series of tests, this technique has been accepted for mass production and has become an inevitable part of the control system of washing machines.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Predictive Repetitive Current Control in Stationary Reference Frame for
           DFIG Systems Under Distorted Voltage Operation

    • Free pre-print version: Loading...

      Authors: Eliomar R. Conde D.;Angelo Lunardi;Luís Felipe Normandia Lourenço;Alfeu J. Sguarezi Filho;
      Pages: 5809 - 5818
      Abstract: This article presents a stationary reference frame implementation of the predictive repetitive controller under ideal and nonideal stator voltage conditions. Thanks to the combination of the model predictive control (MPC) and the repetitive control techniques, the predictive repetitive control uses the capabilities of both techniques to achieve the control objectives without the need of using a PLL for the stator flux in ideal conditions as the approach is developed in the stationary reference frame $alpha beta $ . For the operation of the technique, it is also not necessary to know the harmonic content of the nonideal stator voltage beforehand, but, for this case, and given the nature of the distortions, the use of the PLL is necessary to estimate the phase angle and the magnitude of the voltage’s fundamental component. This means a great advantage over previous techniques due to the fact that special considerations are not needed over the mathematical model of the doubly fed induction generator (DFIG). Experimental results of the proposed technique are presented in ideal and nonideal grid conditions, and under variable rotor speed. Moreover, a comparison with the classic MPC technique is presented.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Seamless Transition for Parallel Inverters With Novel Self-Adaptive Hybrid
           Controller and Presynchronization Unit

    • Free pre-print version: Loading...

      Authors: Xin Meng;Huizhu Guo;Xueqing Wang;Mingzhi He;Jinjun Liu;
      Pages: 5819 - 5832
      Abstract: This article proposes a seamless transition strategy between grid-connected (GC) and stand-alone (SA) states for a microgrid (MG) consisting of parallel inverters. Most inverters in MG operate with novel self-adaptive hybrid controllers, and one inverter near the point of common coupling (PCC) acts as presynchronization (PS) unit. When islanding happens, the inverters based on self-adaptive hybrid control can inherently transfer from grid current control in the GC state to droop control in the SA state, critical islanding detection is needless. When the grid restores, the PS unit can regulate its reactive power to influence the output voltage phase of other inverters in MG and realize the PS of MG and grid. The main advantages are concluded into three points. First, seamless transition of parallel inverters is realized without reconfiguration of control structure, and power-sharing among parallel inverters is achieved without communication lines. Second, unlike droop control, the self-adaptive hybrid control can regulate the grid current of the inverter accurately when the grid fluctuates or is distorted. Third, the PS unit can save the complexity and cost of remote communication for PS. The effectiveness of the proposed seamless transition strategy is verified by simulation and experiment results.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Optimal Sector-Based Sequential Model Predictive Control for Current
           Source Rectifier

    • Free pre-print version: Loading...

      Authors: Gannamraju Siva Kumar;Ravikumar Bhimasingu;
      Pages: 5833 - 5843
      Abstract: Conventional model predictive control (MPC) methods for current source rectifier (CSR) use either a PI controller or weight factor-based methods, which require time-consuming tuning methods to develop an efficient controller. Moreover, the limitations on the bandwidth requirements of the $LC$ filter cause resonances and grid current distortions if a variable switching frequency-based predictive control is used. So, a new fixed switching frequency-based MPC algorithm has been developed to control the load and source current simultaneously, thereby facilitating the weight factor less operation and applying a predefined space vector sequence. Unlike the conventional single cost function methods applied to CSR, the proposed method uses separate cost function for each control variable. Simultaneously, to provide fixed frequency operation, duty ratio-based modulation of grid current control has been applied. A virtual impedance-based active damping has been embedded into the supply current control to suppress the oscillations caused by the $LC$ filter and grid current harmonics. Simulation and experimental results have been supported to validate the improvements in terms of supply current total harmonic distortion (THD), steady state, and transient switching performance.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Integration of Three-Phase LLC Resonant Converter and Full-Bridge
           Converter for Hybrid Modulated Multioutput Topology

    • Free pre-print version: Loading...

      Authors: Guangdi Li;Dongsheng Yang;Bowen Zhou;Yan-Fei Liu;Huaguang Zhang;
      Pages: 5844 - 5856
      Abstract: A multioutput dc–dc topology based on hybrid modulation of pulse frequency modulation and the phase shift is proposed in this article. The proposed hybrid modulated multioutput converter is derived from the integration of a three-phase LLC resonant converter and the full-bridge converter. With the hybrid modulation, the multioutput is controlled independently free from cross-regulation and isolated from each other. With the three-phase interleaving operation, the resonant currents can be reduced, and thus, the efficiency will be improved. Furthermore, the output current ripple of the main output voltage is reduced; as a consequence, the lifetime of the output filter capacitor is extended, and the reliability is reinforced. What is more, the number of the power switches is reduced, and the zero-voltage switching of the power switches can be achieved within the entire load range by the proposed integrated topology. All the abovementioned features of the proposed converter will lead to a compact, efficient, and cost-effective design. Finally, a 1.4-kW triple-output laboratory prototype is built and tested to validate the feasibility and effectiveness of the proposed converter.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Flexible Reactive Power Injection Method for DC-Link Capacitors Voltage
           Balancing in Back-to-Back Multilevel Converters

    • Free pre-print version: Loading...

      Authors: Yao Xue;Chenchen Wang;Jiawei Guo;Trillion Q. Zheng;Xiaofeng Yang;
      Pages: 5857 - 5869
      Abstract: The dc-link capacitor voltage drift is the key technical problem of the converters with multi-intermediate nodes. The back-to-back (BTB) configuration with voltage balancing control can achieve a certain operation range. Nevertheless, the challenge of voltage drift still remains, especially when both sides operate at high but different modulation indexes and high power factors. This article focuses on a BTB seven-level V-clamp multilevel converter (VMC). The balanced operation limits are presented, and the effect of the power factor on balancing capability is analyzed. To maintain the voltage balancing of the dc-link capacitor under different operation conditions of the load (inverter side), a reactive power injection control is proposed in this article. Suitable reactive power is injected into the rectifier according to the balancing situation. The proposed control method can actively adjust the power factor of the rectifier to provide the required balancing capability. In this way, the dc-link capacitor voltage balancing is maintained within a larger operation range. In this article, a 10-kVA laboratory prototype of BTB seven-level VMC is set up to verify the effectiveness of the proposed control.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Application of Newton Identities in Solving Selective Harmonic Elimination
           Problem With Algebraic Algorithms

    • Free pre-print version: Loading...

      Authors: Chenxu Wang;Qi Zhang;Dunzhi Chen;Zhaoyuan Li;Wensheng Yu;Kehu Yang;
      Pages: 5870 - 5881
      Abstract: Algebraic algorithms are powerful methods in solving the selective harmonic elimination (SHE) problem, which can find all exact solutions without the requirements of choosing initial values. However, the huge computational burden and long solving time limit the solving capability of algebraic algorithms. This article presents a novel Newton’s identifies-based method to simplify the SHE equations including the order reduction and the variable elimination, thereby reducing the computational burden and the solving time of algebraic algorithms or in other words improving the solving capability of the algebraic algorithms. Compared with existing simplification methods, the proposed method significantly improves the efficiency of solving SHE equations. With the proposed method, the degree of reduction is no longer the bottleneck of solving the SHE equations by using algebraic algorithms. By using the proposed method, the SHE equations with ten switching angles are completely solved with the algebraic algorithm for the first time. The simulation and experimental results indicate that the proposed method is effective and correct.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Family of Non-Isolated High Step-Up DC–DC Converters Based on the
           Multi-State Switching Cell

    • Free pre-print version: Loading...

      Authors: Paulo Henrique Feretti;Fernando Lessa Tofoli;Enio Roberto Ribeiro;
      Pages: 5882 - 5893
      Abstract: This work presents a family of non-isolated high step-up dc–dc converters for high-power, high-current applications based on the multi-state switching cell (MSSC) and voltage multiplier cells (VMCs). Inherent advantages in the proposed topologies include reduced current and voltage stresses on the semiconductors, improved thermal distribution, good current sharing among the phases, and reduced dimensions of filter elements. Another relevant aspect is that the derived converters present modularity in terms of the possibility of extending not only the voltage gain, but also the rated power. A non-isolated dc–dc boost converter employing the four-state switching cell (4SSC) is thoroughly analyzed. Experimental results obtained from a 1.3-kW prototype are presented and discussed to validate the theoretical assumptions.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • 48-Pulse Voltage-Source Converter Based on Three-Level Neutral Point Clamp
           Converters for Solar Photovoltaic Plant

    • Free pre-print version: Loading...

      Authors: Subir Karmakar;Bhim Singh;
      Pages: 5894 - 5903
      Abstract: The demand for high-power converters for use in large-scale solar photovoltaic (PV) plants increases as the plant size continues to grow. The multipulse voltage-source converter (VSC) configurations are the viable option for high-power solar PV converter applications because they improve conversion efficiency due to low switching losses and allow direct integration with a medium-voltage (MV) grid. In this article, a 48-pulse VSC based on the fundamental frequency switching (FFS) three-level neutral point clamp (NPC) converter with a start–delta transformer configuration is used for large-scale solar PV plant application. It is also used as a PV-static synchronous compensator (STATCOM) to provide the required reactive power support to the grid to regulate the voltage. The solar PV plant configuration for a 100-MW capacity is modeled in MATLAB and implemented in the real-time OPAL-RT platform to verify its design and controls. The harmonics, static, and dynamic performances are demonstrated in detail.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Nine-Level T-Type Converter for Grid-Connected Distributed Generation

    • Free pre-print version: Loading...

      Authors: Ibrahim Harbi;Mostafa Ahmed;Jose Rodriguez;Ralph Kennel;Mohamed Abdelrahem;
      Pages: 5904 - 5920
      Abstract: This article presents a new high-efficiency nine-level T-type converter (9L-T2C) for grid-connected applications based on the three-level T-type converter (3L-T2C). The proposed 9L-T2C outperforms other common dc-link nine-level converters in terms of the required number of active switches and capacitors, flying capacitors (FCs) voltage ratings, and efficiency. Only ten power switches, eight gate drivers, and two FCs are required for each phase. Exploiting the available pole-redundant states, an FCs balancing algorithm is developed to stabilize the two FCs with one voltage sensor in steady-state and dynamic operation. Moreover, an effective balancing method is proposed for dc-link capacitors without the need for further redundant states and integrated into FCs balancing. The FCs and dc-link balance are integrated into the phase-disposition pulsewidth modulation (PD-PWM) method, eliminating the need for an additional controller. Considering the designed PD-PWM method, a mathematical analysis is performed to establish the relationship between the FCs size and the desired ripple. A comprehensive comparison with other converters is provided to demonstrate the merits and application areas of 9L-T2C. The operation of the proposed 9L-T2C with the capacitors’ balancing scheme is validated for stand-alone and grid-connected operation via simulation investigations and experimental setup.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Model-Based Closed-Loop Control for High-Power Current Source Rectifiers
           Under Selective Harmonic Elimination/Compensation PWM With Fast Dynamics

    • Free pre-print version: Loading...

      Authors: Mingzhe Wu;Li Ding;Cheng Xue;Yun Wei Li;
      Pages: 5921 - 5932
      Abstract: Selective harmonic elimination/compensation PWM (SHE/SHC-PWM) is widely used in current source rectifiers (CSRs) under normal/distorted grid conditions due to its best line current harmonic performance with reduced switching losses. However, due to the off-line nature of SHE/SHC-PWM that operates over fundamental frequency, its dynamic performance under closed-loop control is usually not satisfactory compared with the space-vector modulation or carrier-based PWM (CB-PWM) for CSR. To improve the closed-loop dynamics of CSR under SHE/SHC-PWM, a model-based closed-loop control scheme is proposed in this article. In case of transient when the dc current reference of CSR changes, the new input references of the SHE/SHC-PWM module, i.e., the modulation index and delay angle, are directly calculated and updated in real-time based on the mathematical model of CSR derived in this article. As a result, the dynamic performance for dc current tracking under closed-loop SHE/SHC-PWM operations can be improved greatly due to this added model-based feedforward path, while the conventional feedback controller is still adopted but only for steady-state error corrections. The application of the proposed method on back-to-back current source converter (CSC) motor drives is also introduced. Simulation and experimental results validate this proposed control for CSR with fast dynamics.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Improved CPS-PWM Approach for Over-Modulation Operations of Hybrid Modular
           Multilevel Converter

    • Free pre-print version: Loading...

      Authors: Yaqian Zhang;Jianzhong Zhang;Fujin Deng;
      Pages: 5933 - 5943
      Abstract: The over-modulation capability of the hybrid modular multilevel converter (MMC), mixed by half-bridge and full-bridge submodules (SMs), has acquired widespread attention recently, which can significantly increase the design freedom of the hybrid MMC. When the hybrid MMC is applied in the medium-voltage occasions, an improved carrier phase shift pulsewidth modulation (CPS-PWM) approach is put forward in this article for its over-modulation operation under the nominal and variable dc conditions. It is featured with high flexibility, adjustability, and simple implementation. A new standard voltage is introduced to normalize the modulation wave, by which there is always a sufficient margin between the peaks of the normalized modulation wave and carrier waves under any modulation indexes. Also, it can perform well when the nominal dc voltage of the hybrid MMC is not the integer multiple of SM voltage. Moreover, the carrier wave arrangements are decoupled with the number of SMs, dc voltage, and ac voltage, so the variable dc operation of the hybrid MMC can be achieved without rearranging the carrier waves. Finally, the simulations and experiments are carried out to confirm the effectiveness of the proposed CPS-PWM approach for over-modulation operations under the steady-state and variable dc conditions.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Noise-Tolerant LLC Synchronous Rectification Using Volt-Second Product

    • Free pre-print version: Loading...

      Authors: Jhih-Da Hsu;Martin Ordonez;Wilson Eberle;Marian Craciun;Chris Botting;
      Pages: 5944 - 5955
      Abstract: Synchronous rectification (SR) technologies for $LLC$ resonant converters are essential to high-power, low-voltage battery chargers considering the excessive current stress on the rectifiers. Mainstream SR controllers employ an adaptive approach that measures the drain–source voltage during the SR turn-on phase ( $v_{text {ds.on}}$ ). However, $v_{text {ds.on}}$ is low-magnitude and sensitive to the voltage across parasitic inductors and capacitors. The distortion of $v_{text {ds.on}}$ causes SR mistriggering, undermining the efficiency. This article proposes a noise-tolerant SR strategy based on the volt-second product (VSP) of SR drain–source voltage in the turn-off phase and rectifier current conduction time. The proposed method determines SR ON-time using high-magnitude voltage signals, which are tolerant of parasitic effects. In steady-state operation, the VSP method reduces the SR ON-time error caused by circuit parasitic components, whereas in transient operation, the algorithm dynamically adjusts SR ON-time to maintain a safe operation margin, preventing rectifier reverse current flow. Details of the implementation and timing sequence are provided to demonstrate the simplicity and effectiveness of the VSP SR algorithm. Experimental results show that compared with conventional adaptive SR, the proposed VSP SR decreases the ON-time error by 64% in the above-resonance operation and removes the reverse current in the below-resonance operation, which reduces the total loss by 3%.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Comparison Between Interconnected Filter Blocks for Three-Phase
           AC–DC Interleaved Converters

    • Free pre-print version: Loading...

      Authors: Ripun Phukan;Sungjae Ohn;Sebastian Nielebock;Gopal Mondal;Dong Dong;Rolando Burgos;
      Pages: 5956 - 5968
      Abstract: Three-phase ac filters occupy more than 30%–40% of the total power electronics (PEs) system volume. With interleaved operation, the size of three-phase line harmonic filters can be reduced at the expense of high circulating current between channels. Additional filter for circulating current mitigation is required, which contributes to incremental volume. The challenge is to achieve a truly optimized and modular solution for interleaved converters, while effectively blocking circulation. Two concepts are considered, i.e., magnetic and electrical interconnection between filter blocks for parallel converters. These interconnecting methods are integrated with conventional filter structures, such as the LCL filter, to achieve filter building block (FBB) configurations. A design procedure is formulated for the two FBB configurations to compare the loss-volume map of each FBB. Brief experimental and analytical comparison is performed to distinguish between the two topologies. It is found that from modularity point of view, the electrically interconnected FBB can be a favorable option and candidate for high power applications.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Novel Array-Type Symmetrical CI for Multiphase Interleaved DC–DC
           Converters

    • Free pre-print version: Loading...

      Authors: Lei Wang;Donglai Zhang;Linlin Lyu;
      Pages: 5969 - 5986
      Abstract: For conventional parallel multiphase coupled inductor (CI), it is difficult to achieve full symmetrical coupling. A novel multiphase array CI is proposed, along with the analysis of the relevant symmetry principle, topology combination, and design method. Planar design and exploration are performed, which are then generalized to design a universal $n$ -phase symmetrical CI and ring-type array CI with head and tail sequence coupling. The universal design criteria for multiphase symmetrical CI are summarized. Finally, soft switching mechanism is investigated under symmetrical inductance, thereby alleviating the problem of low efficiency at light load. The experimental results prove that the multiphase symmetrical array CI theory is valid and practical.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Asymmetrical PWM Scheme to Widen the Operating Range of the Three-Phase
           Series-Capacitor Buck Converter

    • Free pre-print version: Loading...

      Authors: Viet-Chan Nguyen;Honnyong Cha;Dai-Van Bui;
      Pages: 5987 - 5996
      Abstract: The three-phase series-capacitor (3P-SC) buck converter is analyzed extensively in this study for high-voltage step-down applications with a wide input voltage range. This structure is attractive due to its high step-down conversion ratio and inherent current balancing. However, the inductor currents of the 3P-SC converter become unbalanced when the duty cycle exceeds 1/3. This results in significant stress and reduces the utilization of switching devices. This article proposes an asymmetrical pulsewidth modulation (PWM) scheme for the 3P-SC converter to overcome the limitations of the conventional PWM scheme. By using the proposed switching scheme, the duty cycle can be increased to one while retaining the high conversion ratio and current balancing functionality. Thereafter, the proposed asymmetrical PWM strategy is generalized for multiphase series-capacitor (nP-SC) converters. Finally, to validate the performance of the proposed PWM strategy, a 1.2-kW prototype 3P-SC converter is fabricated and tested.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • High-Frequency GaN-Based ANPC Three-Level Converter as a Low-Noise
           Arbitrary PWL Voltage Generator

    • Free pre-print version: Loading...

      Authors: Vladan Ž. Lazarević;Miroslav Vasić;
      Pages: 5997 - 6008
      Abstract: Recent advances in the technology of gallium nitride (GaN) power devices and high-frequency magnetic materials are key enablers of small, compact designs of power electronic converters in the megahertz range and the power range up to several hundreds of watts. However, impact of different switch modulation strategies along with the devices and magnetic materials must be carefully characterized to fully understand the boundaries of current technology and to be able to exploit it fully. This is usually performed through a holistic, automated design procedure based on multiobjective optimization which focuses on the converter efficiency and power density for the given electrical parameters. In this article, an optimized 100-W, 1.75-MHz switching frequency, four-quadrant, piecewise linear (PWL) arbitrary voltage generator based on active neutral-point-clamped (ANPC) three-level converter is presented. Diversity of modulation techniques for the hard-switched ANPC converter suitable for high-frequency (HF) applications are revisited, and impact on switching losses is characterized in detail. The generator is capable of providing $pm {mathrm {100}}~text {V}$ and $pm {mathrm {1}}~text {A}$ at the output, with tracking speeds up to $2~text {V/}mu text {s}$ and steady-state efficiency above 95% with a physical size less than $12~text {cm}^{2}$ . Thermal management of the system is successfully resolved using advanced cooling plates based on pyrolytic graphite sheets (PGSs) and forced air convection. Having these characteristics, the presented generator outperforms the existing linear and hybrid power amplifiers (LPA/HPA) from the literature.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A New Resonator Design for Wireless Battery Charging Systems of Electric
           Bicycles

    • Free pre-print version: Loading...

      Authors: Heshou Wang;Ka Wai Eric Cheng;Yun Yang;
      Pages: 6009 - 6019
      Abstract: This article presents a new resonator design scheme for wireless battery charging systems of electric bicycles (EBs). The newly designed method is established based on a switched series (S)-series parallel (SP)/S compensation scheme and Helmholtz coils for the transmitting coils. The Helmholtz coils are adopted to ensure that the mutual inductance between the transmitting and receiving coils is invariant. For this reason, the switched S-SP/S compensation scheme can be used to implement load-independent constant current (CC) and constant voltage (CV) charging for the battery loads instead of using the conventional LCL or LCC compensation schemes. The advancements of the proposed design, as compared to the conventional methods for wireless EB charging, are more than constant mutual coupling and elimination of compensated inductors. The communication channel between the transmitter and receiver, additional user-end converter, and complicated control algorithms can also be annihilated. Simulation results using Maxwell verify that the mutual inductance of the proposed resonator is constant. Experimental results validate that the output current and voltage can be well-regulated to track the references at 1.2 A and 24 V, respectively, at different load conditions. Especially, the maximum efficiency can reach 97.17% in the CC charging mode, whereas 91.17% in the CV charging stage. The maximum output power is 115 W on the load side. This design can be generalizable to other power levels to meet different charging demands.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Novel Family of Flying Inductor-Based Single-Stage Buck–Boost
           Inverters

    • Free pre-print version: Loading...

      Authors: Naser Vosoughi Kurdkandi;Oleksandr Husev;Oleksandr Matiushkin;Dmitri Vinnikov;Yam P. Siwakoti;Sze Sing Lee;
      Pages: 6020 - 6032
      Abstract: Single-phase buck–boost inverters are very popular nowadays due to the wide input voltage range regulation capability. This feature is mostly demanded by photovoltaic (PV), fuel cell, or battery storage applications. In this study, four new structures from the family of flying inductor (FI)-based inverters are presented. Performance in a wide range of input dc voltages and the ability to increase the voltage in single-power processing stage is one of the features of the proposed structures. Three of the four structures are common ground and completely bypass the parasitic capacitors which make them attractive for PV application. Nonuse of electrolytic capacitors in the proposed structures helps to increase the life of the converter and also there is no unpleasant inrush current of charging electrolytic capacitors in these structures. The operation modes are fully explained, as well as the theoretical analysis and design of passive elements have been done. Finally, the simulation and 2 kW laboratory circuit for the proposed Type-III structure are performed and the results are investigated.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Design and Analysis of LLC Resonant Converter With Valley Switching
           Control for Light-Load Conditions

    • Free pre-print version: Loading...

      Authors: Jing-Yuan Lin;Pin-Hsien Liu;Hsuan-Yu Yueh;Yi-Feng Lin;
      Pages: 6033 - 6044
      Abstract: The LLC converter has been widely used in the power supply industry for its high conversion efficiency. When the output load is low, the LLC resonant converter will substantially increase the operating frequency, thereby reducing the conversion efficiency and exceeding the limited operating frequency of the specification. Thus, burst-mode control is applied to increase the ability of regulation at light-load conditions. Even so, the switching period of power switches still occurs at a high switching frequency. Burst-mode control will also result in an extremely low-frequency output voltage ripple. In this study, a valley switching control (VSC) for the LLC resonant converter at light-load conditions is proposed. The VSC control strategy maintains the output voltage by modulating the pulsewidth signals of drivers and achieves valley switching by modulating the switching frequency. Thus, the VSC strategy can reduce the operating frequency compared with the frequency modulation strategy. Compared with burst-mode operations, the proposed VSC effectively reduces the switching loss and has the advantage of high-frequency output voltage ripple. The VSC increases the efficiency and the power quality of the converter. Detailed analysis and design of the proposed method are described. Experimental results are recorded for a prototype converter with a dc input voltage of 400 $V_{mathrm {DC}}$ , an output voltage of $48~V_{mathrm {DC}}$ , and an output current of 12.5 A.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Novel 17-Level Reduced Component Single DC Switched-Capacitor-Based
           Inverter With Reduced Input Spike Current

    • Free pre-print version: Loading...

      Authors: Ashutosh Kumar Singh;Rajib Kumar Mandal;
      Pages: 6045 - 6056
      Abstract: Multilevel inverters (MLIs) have become common and resourceful as a result of the fast advancement of technology in the areas of high-voltage and high-power applications, among other things. Recently, MLIs have received a great deal of attention recently, due to the growing need to harness environmentally friendly energy. With reduced power electronics switches, diodes, and a voltage boost gain factor of 8, this article presents a single-phase 17-level switching capacitor inverter design. The proposed inverter uses single dc voltage source, two diodes, 14 power electronics switches, and three capacitors. The different mode of operation of topology is explained in detail, including their self-voltage balancing technique. Additionally, an inductor is used in the capacitor charging loop to avoid current spikes caused by the input dc source while charging the capacitor quickly, thereby increasing capacitor life expectancy significantly. Compared to previously the proposed single-input MLIs, the proposed inverter has a lower semiconductor switch count and a lower cost function value that are its distinguished feature. The performance of the topology is verified by MATLAB/Simulink, and furthermore, a laboratory prototype is utilized, which confirms the feasibility of the proposed topology.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • ZVT High Step-Up Boost Converter With Wide Input Voltage and Wide Output
           Power for Renewable Energy Applications

    • Free pre-print version: Loading...

      Authors: Ramin Rahimzadeh Khorasani;Hamed Moradmand Jazi;Arash Khoshkbar-Sadigh;Nilanjan Ray Chaudhuri;Mahdi Shaneh;Najmehossadat Nourieh;Ehsan Adib;Patrick Wheeler;
      Pages: 6057 - 6069
      Abstract: In this article, a high-efficiency, high step-up dc–dc converter is introduced by utilizing a new soft-switching circuit based on the zero-voltage transition (ZVT) technique. Soft-switching performance is independent of the output load and input voltage. The simple auxiliary circuit benefits from a low number of components. The resonant circuit comprises merely one switch and one small capacitor, and in comparison to the existing ZVT high step-up converters, no extra auxiliary diode and resonant inductor are used to provide soft switching. The proposed auxiliary circuit can be applied to coupled inductor (CI)-based step-up topologies, because of exploiting the leakage inductance of the CI cell in the resonant network. Providing soft-switching performance for all the semiconductor elements alleviates the reverse recovery and switching losses, which considerably enhances the efficiency. The proposed topology is a competitive structure in terms of efficiency, voltage gain ratio, and the number of components due to the mentioned features. The theoretical results are validated on a 200-W laboratory prototype with a 400-V output voltage.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Research on the Voltage Spike Suppression Strategy for Three-Phase High
           Frequency Link Matrix-Type Inverter

    • Free pre-print version: Loading...

      Authors: Youzheng Wang;Hongchen Liu;Patrick Wheeler;
      Pages: 6070 - 6083
      Abstract: The problem of high-voltage spikes on the secondary side of a high-frequency transformer (HFT) in the commutation process of a three-phase high-frequency link matrix-type inverter (HFLMI) is studied. Considering the parasitic capacitance of MOSFETs, the mechanism of voltage spikes during HFLMI commutation is revealed. According to the characteristics of the topology, the later stage matrix converter (MC) is decoupled into two groups of conventional three-phase voltage type inverters by the de-re-coupling idea, and the space vector pulsewidth modulation (SVPWM) is carried out, respectively. The zero vector is inserted between two nonzero voltage vectors to accomplish smooth commutation for addressing the problem of voltage overshoot on the secondary side of HFT due to the switching of HFT leakage inductance and filter inductance to the same path. Due to the existence of parasitic capacitance, the voltage spikes caused by its resonance with the system’s stray inductance cannot be solved by optimizing modulation strategies. In order to further suppress voltage spikes, a flyback clamp circuit is proposed to absorb the leakage inductance energy. Ultimately, a prototype with a rated power of 200 W is developed for experimental verification. The results show that the peak efficiency of three-phase HFLMI with the flyback clamp circuit is 92.6% in the full power range, the voltage spikes on the secondary side of HFT are clamped to about 1.2 times the rated voltage, and all switches realize soft-switching.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Novel Single-Phase Multilevel High-Gain Inverter With Low Voltage Stress

    • Free pre-print version: Loading...

      Authors: Fatemeh Esmaeili;Hamid Reza Koofigar;Hossein Qasemi;
      Pages: 6084 - 6092
      Abstract: This article proposes a high performance with 13-step, switched-capacitor multilevel inverter (SCMLI). The gain factor of 6 is achieved, along with self-voltage balancing of capacitors. The suggested structure can be cascaded to generate any number of voltage steps with the inherent property of generating both positive and negative voltage steps. All the power switches withstand voltages lower than 50% of maximum output voltage. The number of power switches, the number of dc input sources, the voltage stress on the switches, and the power losses are reduced. Also, the presented inverter has a minimum cost function compared to the other similar structures. The performance of the proposed 13-step converter has been validated by the simulation, extracted by PSCAD/EMTDC, and also the experimental results, obtained from an implemented laboratory prototype.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Novel Switched Capacitor Quadruple-Boost Inverter Configuration for 3ϕ
           Induction Motor Drive

    • Free pre-print version: Loading...

      Authors: Arpan Hota;Vivek Agarwal;
      Pages: 6093 - 6100
      Abstract: A novel switched capacitor (SC) quadruple-boost inverter configuration for low-power $3phi $ induction motor (IM) drive applications is proposed, which is built by cascading a novel switched capacitor network (SCN) with a traditional six-switch $3phi $ inverter ( $3phi text{I}$ ). The SCN can boost the input dc voltage up to four times. Compared to a traditional $3phi text{I}$ , where the dc-link voltage is fixed, the SCN in the proposed configuration facilitates two discrete voltage levels 3 and $4V_{mathrm {dc}}$ , resulting in a complex two-layer space vector (SV) hexagon. Accordingly, a novel SV pulsewidth modulation (PWM) is proposed to handle a general multilayer SV hexagon, which is then customized to control the proposed configuration. A switching function-based state-space model of the proposed topology is also presented. A comparative study between the proposed SCN and the existing SCNs is carried out to highlight that the proposed SCN has the lowest component count. An experimental prototype of the proposed topology to run a low-power $3phi $ IM has been built and operated with $v/f$ control strategy, which exploits the advantage of the proposed multilayer SVM. It is observed that the proposed system performs well. Key experimental results are presented and discussed to support the theoretical claims.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Dual Closed-Loop Control Strategy on Harmonic Plane for Multiphase
           Induction Motor With Harmonic Injection Based on Air-Gap Flux Orientation
           Control

    • Free pre-print version: Loading...

      Authors: Sheng Li;Jiaqiang Yang;Yan Wang;Guanghui Yang;
      Pages: 6101 - 6111
      Abstract: Multiphase motors, compared to three-phase motor, have many advantages, such as multiple degrees of freedom and flexible control. However, if these advantages are used incorrectly, it will increase the loss of the motor and decrease the efficiency. In response to this problem, this article lists the three limiting conditions that make the air-gap flux as quasi-trapezoidal waveform and analyzes the reasons why the traditional method cannot make the air-gap flux perfectly distributed. Therefore, a dual closed-loop feedback control structure on the harmonic plane was proposed. In this article, the feasibility and stability of the proposed method are analyzed. A series of comparative experiments on a seven-phase induction motor with concentrated windings platform is given. Finally, a conclusion that the proposed method not only can achieve a better electromotive force (EMF) waveform but also can increase torque per ampere is drawn.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Polynomial Estimation of Flux Linkage for Predictive Current Control in
           PMSM

    • Free pre-print version: Loading...

      Authors: Huixuan Zhang;Tao Fan;Liu Meng;Jing Guo;Xuhui Wen;
      Pages: 6112 - 6122
      Abstract: This article presents an automatic parameter identification method based on ordinary least square (OLS) algorithm for deadbeat predictive current control (DPCC) to fulfill the purpose of high steady and dynamic performance in permanent magnet synchronous motor (PMSM) drives. Different from the conventional model, a novel model based on the polynomial estimation of flux linkage is constructed which takes the cross-saturation effects into account. First, the conventional mathematical model of PMSM and the proposed model are presented, respectively, and the inverter considering nonideal factors is also analyzed. Then the parameter identification method is investigated, in which the measurement procedure is delimited in advance and the automatic identification method is developed. Furthermore, a voltage reconstruction algorithm is applied to solve the inverter nonlinearities and the digital time-delay effect, so as to improve the accuracy of the identified parameters. Accordingly, a novel DPCC algorithm is presented based on the proposed model to achieve better performance. Finally, based on the concept and principles mentioned before, a detailed comparison of the DPCC based on the classical model considering the parameters’ variation and the modified model of the proposed method is carried out on a laboratory prototype.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Indirect Method to Measure of Initial Mover Position in Flux-Modulated
           Linear Actuator for Five-Axis Gantry Robot Using Low-Cost Current Sensors
           and Considering End Effect

    • Free pre-print version: Loading...

      Authors: Sarbajit Paul;Junghwan Chang;
      Pages: 6123 - 6134
      Abstract: An initial mover position (IMP) detection algorithm for a dual-saliency flux-modulated permanent magnet linear synchronous motor (DS FM-PMLSM) for a five-axis gantry robot has been proposed in this proposed work. The proposed IMP algorithm uses the saliency of the proposed machine, which results in the inductance variation and checks the change in the inductance by providing sequential current profiles. The effect of the end region at the entry and exit are included to check the robustness of the proposed IMP. A design platform using MATLAB and Altair-Flux has been developed to simulate the proposed IMP algorithm for different positions of the mover. Based on the simulation model, a test setup is developed using a low-cost sensor and six-step inverter and tested the validity of the proposed IMP algorithm for the DS FM-PMLSM.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Multidisturbance Suppressed Model Predictive Direct Speed Control With Low
           Pulsation for PMSM Drives

    • Free pre-print version: Loading...

      Authors: Yanping Xu;Jinglu Ren;Luyang Fan;Zhonggang Yin;
      Pages: 6135 - 6147
      Abstract: Model predictive direct speed control (MPDSC), with a simple structure and without parameter tuning required, can use only one controller to constrain the speed and current of the motor at the same time. First, a direct voltage vector selection-based three-vector model predictive speed control, simplifying the optimization process, is proposed in this article, which reduces the pulsation of current and speed without increasing the computational burden compared with MPDSC. At the same time, because of the reasonable distribution of voltage vectors in the proposed three-vector method, the quality of the control and modulation has been significantly improved. Second, a multidisturbance Luenberger observer is designed to observe mechanical and electrical disturbances and to make further compensation, which reduced the influence of model mismatch, load torque, and unmodeled dynamics simultaneously and avoided the use of multiple observers, with fewer parameters and easier tuning. The experiment is presented to validate the effectiveness of the proposed method on the 7.5-kW experiment platform.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Torque Ripple Compensation With Anti-Overvoltage for Electrolytic
           Capacitorless PMSM Compressor Drives

    • Free pre-print version: Loading...

      Authors: Junya Huo;Nannan Zhao;Runfeng Gao;Gaolin Wang;Guoqiang Zhang;Dianguo Xu;
      Pages: 6148 - 6159
      Abstract: As the dc-link capacitance decreases obviously, the dc-link voltage fluctuates severely in the electrolytic capacitorless permanent magnet synchronous motor (PMSM) drives for compressor applications. The control performance of the compressor deteriorates, and the dc-link may suffer from the fault of overvoltage. In this article, an acceleration extraction-based torque ripple compensation method considering safe operation with dc-link anti-overvoltage is proposed for electrolytic capacitorless PMSM compressor drives. The fluctuation characteristics of the compressor torque and the speed caused by the interaction of the dc-link voltage and the load are analyzed. The load torque is estimated online using the orthogonality theory to suppress the torque ripple. Based on the hybrid proportional–integral–resonant regulator, an anti-overvoltage control strategy is proposed for the safe operation of the regenerating state. Experimental results are performed in the air-conditioner compressor drive system to verify the effectiveness of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Robust Composite Finite-Time Convergent Speed Control of Induction Machine
           Based on Multiple Sources Disturbance Estimation Technology Generalized
           Proportional Integral Observer

    • Free pre-print version: Loading...

      Authors: Cong Bai;Zhonggang Yin;Jiawei Luo;Peien Luo;Jing Liu;
      Pages: 6160 - 6170
      Abstract: To improve the robustness of the conventional finite-time convergent speed controller (FTCSC) against unpredictable disturbances, a finite-time generalized proportional integral observer (FT-GPIO) is proposed based on the state observer to achieve finite-time convergence of the closed-loop control system. First, an FTCSC is devised to improve the speed convergence performance of the induction machine (IM) control system. However, the system will inevitably be affected by multiple sources disturbances, such as friction, load disturbance, parameter mismatch, and torque current tracking error, resulting in performance degradation. To improve the disturbance rejection ability of the IM control system, an FT-GPIO based on multiple sources disturbance estimation technology is designed. Finally, a 1.1-kW IM is used as a case study, and the experimental results are provided to verify the effectiveness of the proposed robust composite finite-time convergent speed controller.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Investigation of Vehicle-Oriented Double-Sided Cooling Power Module With
           BGA Technology

    • Free pre-print version: Loading...

      Authors: Cheng Peng;Wenhui Zhu;Pan Ke;Ran Li;Xiaoping Dai;Liancheng Wang;
      Pages: 6171 - 6179
      Abstract: With the increasing power density and integration of power electronics for motor drive applications, lower parasitic parameters, higher heat dissipation, thermomechanical reliability, and manufacturability have become the focused requirements of automotive power modules. New structures and materials have been investigated for the packaging of power modules, and wire-bondless packaging technology has become a research focus. In this article, a wire-bondless power module packaging technology based on ball-grid array (BGA) was developed, and a double-sided cooling (DSC) power module was then fabricated and thoroughly investigated. Thermal, electrical, and mechanical properties of the BGA packaged module were analyzed from the aspects of electrothermal coupling, shear performance, and electrical test. Specifically, by using the BGA interconnection, the thermal resistance was decreased by 27.4% compared to the wire-bond module. Parasitic inductance of BGA-based module was measured to be 10.13 nH by the dynamic test under the conditions of 310 V/120 A, which decreased by 33.3% compared to the wire-bond module counterpart. The findings of this work can help advance the design and fabrication of power modules, specifically DSC power modules.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Inverter Nonlinearity Compensation for Open-Winding Machine With Dual
           Switching Modes

    • Free pre-print version: Loading...

      Authors: Lei Xu;Z. Q. Zhu;
      Pages: 6180 - 6191
      Abstract: In this article, a novel inverter nonlinearity compensation method is proposed for open-winding (OW) machines fed by isolated dc-bus dual two-level three-phase inverters with dual switching modes. Inverter nonlinearity of dual inverters is analyzed in both balanced and unbalanced switching modes, and the different voltage distortions are utilized for a closed-loop inverter nonlinearity compensation by alternately applying the two switching modes. The proposed strategy needs no off-line measurement for the parameters of dual inverters and the electrical machine, and can also deal with the variation of inverter parameters in different operation conditions. Furthermore, the proposed strategy can overcome issues in conventional current harmonic-based methods, such as the need for accurate rotor position and preset compensation voltage curves. Experimental results verify the performance of the proposed inverter nonlinearity compensation method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Hybrid Extended Phase Shift Modulation Strategy for DAB Converter With
           DC Blocking Capacitor to Extend ZVS Range and Reduce RMS Current

    • Free pre-print version: Loading...

      Authors: Guo Xu;Jian Tang;Lulin Zhang;Wenjing Xiong;Yao Sun;Mei Su;
      Pages: 6192 - 6207
      Abstract: This article is aimed at enlarging the zero-voltage switching (ZVS) range and reducing current stress for the dual-active-bridge (DAB) converter with dc blocking capacitors (DCBCs). A hybrid extended phase shift modulation strategy (HEPSMS) is proposed, which makes the converter switch between the full-bridge mode and the half-bridge mode to obtain multivoltage matching operation points. Thus, the root mean square (rms) current and the burden of achieving full load range ZVS are reduced. In addition, the voltage–second of the leakage inductor is controlled to achieve equivalent voltage matching under wide voltage output, thereby simplifying the control law and achieving full load range ZVS under a wide voltage range. The operation principle, ZVS range, and rms current are analyzed and compared with the conventional modulation method. Finally, a 1-kW experimental prototype with a 200-V input and a 100–400-V output was built to verify the feasibility and effectiveness of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Solar-Battery-Integrated Hybrid AC/DC Off-Grid System for Rural Households
           Based on a Novel Multioutput Converter

    • Free pre-print version: Loading...

      Authors: Amal C. Sunny;Nagarjun Surulivel;Dipankar Debnath;
      Pages: 6208 - 6217
      Abstract: Solar fed off-grid system capable of catering dc and ac loads simultaneously with battery backup seems to be a propitious solution for rural electrification. However, such hybrid ac/dc off-grid systems reported in the literature have one or more of the following limitations: 1) higher number of converter stages and switch counts; 2) inadequate voltage gain; 3) use of bulky and costly low-frequency transformer; 4) lack of maximum power point tracking (MPPT) capability; 5) lack of battery charge control and/or over-charge/deep discharge protection; 6) series connection of several photo-voltaic (PV)/battery units; 7) lack of ac and/or dc load voltage regulation; and 8) use of a dedicated converter for MPPT control. A two-stage hybrid ac/dc off-grid system can be formed by integrating some of the high-frequency transformer-based four-port dc–dc converters reported in the literature. However, such dc–dc converters have higher number of control variables than required for this application thus leading to higher switch count. To overcome all these limitations of existing schemes, this article proposes a two-stage hybrid ac/dc off-grid system capable of catering ac and dc household loads simultaneously. All of the claims of this scheme are substantiated through exhaustive experimental validation carried out on a 400-W laboratory prototype.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Family of Non-Isolated Quadratic High Gain DC–DC Converters Based on
           Extended Capacitor-Diode Network for Renewable Energy Source Integration

    • Free pre-print version: Loading...

      Authors: Sija Gopinathan;Vemparala Seshagiri Rao;Kumaravel Sundaramoorthy;
      Pages: 6218 - 6230
      Abstract: Many topologies in the area of non-isolated high-voltage gain dc–dc converter are reported for improving efficiency and voltage gain and to reduce the switch stress with the use of minimum number of components. A family of quadratic high-gain dc–dc converters using an extended capacitor–diode network is proposed in this article, and an extensive analysis has been conducted to assess their performances. The output voltage of the five proposed converters by considering the effect of parasitic elements is derived, and the analytical efficiency profiles are drawn. The proposed converters are designed for 650 V, 0.5 kW, and 50 kHz with a 48-V input source. The hardware prototypes are fabricated for the five converters, and the experimental results are presented. For the considered design, converters I and III give higher efficiency and lower voltage stress on the semiconductor devices. Converters IV and V are suitable for higher voltage gain applications. A dynamic model for converter I is derived and a controller is implemented for closed-loop operation. A suitable converter among the family can be selected according to the applications for the integration of renewable energy sources.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Double-Layered Droop Control-Based Frequency Restoration and Seamless
           Reconnection of Isolated Neighboring Microgrids for Power Sharing

    • Free pre-print version: Loading...

      Authors: Sandipan Patra;Malabika Basu;
      Pages: 6231 - 6242
      Abstract: This article describes a seamless reconnection topology for power sharing between distant rural community microgrids (CMGs), which is based on a double-layered droop-controlled (DLDC) frequency restoration scheme. Increased load demand, along with the intermittent nature of renewable energy sources, may result in a power deficit in isolated CMGs. In order to overcome this restriction, the connection of autonomous neighboring CMGs may be a viable alternative to intelligent load shedding. When dealing with active power fluctuation and setting a frequency set point becomes difficult in the absence of a grid frequency reference, this DLDC-based approach can resolve the issue. The DLDC adds a self-synchronized feature by parallel shifting of the $f - P$ slope to restore the operating frequency to its nominal value. The difference in frequency enables to shift the voltage axis accordingly through the change in $V_{d}$ and $V_{q}$ reference of the terminal voltage for appropriate power sharing. The stability of the proposed controller has been analyzed by using a mathematical model considering communication delay in the distributed secondary controller. Finally, the efficacy of the proposed controller is shown via the use of unique processor-in-the-loop (PIL) experimental findings, in which OPAL-RT and PLECS RT boxes are used to build both the CMGs and a TI-based F28069M microprocessor is utilized as a controller.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Grid Fault Current Injection Using Virtual Synchronous Machines Featuring
           Active Junction Temperature Limitation of Power Devices

    • Free pre-print version: Loading...

      Authors: Fabio Mandrile;Fausto Stella;Enrico Carpaneto;Radu Bojoi;
      Pages: 6243 - 6251
      Abstract: The recent years have seen exponential growth in electric generation from renewable energy sources (RESs), such as wind and sun. This scenario represents an opportunity to decarbonize part of the energy sector and phase out fossil fuels. However, particular care must be taken to ensure the correct operation of the electric grid. With a large penetration of power electronics-based generation, special care must be taken in the case of grid faults, due to limited short-circuit current capabilities of static converters, supporting the grid in the case of faults. For this reason, static converters have to be transiently overloaded to inject fault currents larger than their nominal limit, mimicking the behavior of synchronous generators (SGs). Therefore, this article proposes the combined solution of a transiently overloadable virtual synchronous machine (VSM) converter equipped with real-time semiconductor junction temperature limitation. The VSM provides the necessary short-circuit current references and the inverter can be overloaded with an active thermal control strategy, avoiding the oversizing of the power semiconductors, by properly exploiting their thermal limits. This represents a possible path for further power electronics integration into the grid.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • DC/DC Stage Contribution to Bus Voltage in 1000- and 1500-V Grid-Connected
           Solar Inverters

    • Free pre-print version: Loading...

      Authors: Branislav Stevanović;Emanuel Serban;Santiago Cóbreces;Pedro Alou;Martin Ordonez;Miroslav Vasić;
      Pages: 6252 - 6265
      Abstract: Modern architectures of transformerless, three-phase-grid-connected photovoltaic (PV) inverter for 1000- and 1500-V commercial/residential applications are analyzed and compared from the point of view of the energy harvested during one year period, system efficiency, and power density. Scenarios for different ac grid voltage levels and inverters topologies are analyzed based on one- and two-stage solutions. The architectures with and without included dc/dc stage are compared from the point of view of the optimized power density. In the case of the two-stage PV inverter architecture, the mini-boost converter concept, presented in previous publications, is extended and the standard boost topology that employs 1200-V rated IGBTs and diodes is replaced by a multilevel, hybrid power converter topology that exhibits high efficiency due to the partial power processing and new classes of 900- and 650-V SiC and GaN devices employed. The inverter’s output filter design space (DS) has been researched from the point of view of the dc bus voltage variation. The cases are analyzed for fully controlled bus voltage at its minimum value and when allowed to vary in the full MPP range. Optimization results of the output filter DSs for the minimum and maximum operating dc bus voltage are compared in terms of the occupied volume in order to investigate whether it is possible to obtain more compact inverter stage by better control of dc bus voltage. The results show that in the case of controlled low dc bus voltage level, it is feasible to design a filter that occupies up to 50% less volume than the filter designed for the full MPP voltage variation. Even more, this can be achieved by maintaining the system efficiency. The simulation and experimental results complement the analysis of the 1000- and 1500-V grid-connected PV inverter systems.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Robust Multiloop Disturbance Rejection Controller for a Doubly Fed
           Induction Generator-Based Wind Energy Conversion System

    • Free pre-print version: Loading...

      Authors: Prangya Parimita Pradhan;Bidyadhar Subudhi;Arnab Ghosh;
      Pages: 6266 - 6273
      Abstract: The doubly fed induction generator (DFIG) is a nonlinear system with various uncertainties, including parameter changes, wind speed variations, and rapid dynamic fluctuations, making model-based control techniques challenging to implement. Hence, the multi-loop active disturbance rejection controller (MADRC) is proposed as an enhanced active disturbance rejection control to stabilize and reject external disturbances and system uncertainties. In this article, two active disturbance rejection controllers (ADRCs) are connected in series to achieve the rotor side converter (RSC) controller. The performance of the proposed control strategy is first evaluated using simulation on a 3.7-kW DFIG setup, and subsequently on a 1-kW DFIG-based wind energy conversion system (WECS) developed in our laboratory. The proposed controller is compared to a proportional-integral (PI) controller, single-loop active disturbance rejection controller (SADRC), and sliding mode controller (SMC) in order to demonstrate its effectiveness. The obtained outcomes are evaluated for reference tracking, robustness to parameter fluctuation, and disturbance rejection in DFIG. External disturbances and system uncertainties are effectively mitigated by the proposed MADRC scheme.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Control and Stability of Modular DC Swarm Microgrids

    • Free pre-print version: Loading...

      Authors: Hannes Kirchhoff;Kai Strunz;
      Pages: 6274 - 6292
      Abstract: Direct current (dc) microgrids have not yet achieved the promise of true plug-and-play characteristics due to stability issues stemming from power converters. Swarm microgrids, a type of dc microgrids, are aimed at delivering a modular and easy-to-expand infrastructure. In this article, an application-specific control strategy is developed to ensure stable and expandable swarm microgrids. This control strategy makes use of the widely available distributed storage in swarm microgrids and includes active damping techniques at power-drawing units. Utilizing a cascaded state-space system model, experimental validation with dual-active-bridge converters, and eigenvalue robustness analysis, this article demonstrates a high margin of stability for expandable swarm microgrids. The analysis includes variation of the microgrid size and line parameters, among others. The results show that swarm microgrids are stable for up to at least 1000 participating swarm units. As part of the robustness analysis of swarm microgrid stability, specific definitions are provided for the allowed behavior of the power converters used in a swarm microgrid. The developed methodology allows assessing and designing for swarm microgrid stability even without knowledge of the internal structures of the power converters. As such, this article provides a practical framework to support the scaling up of swarm microgrid deployment.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Multistep Charge Extractions and Voltage Bias-Flip (MCEBF) Interface
           Circuit for Piezoelectric Energy Harvesting Enhancement

    • Free pre-print version: Loading...

      Authors: Li Teng;Shiying Wang;Junrui Liang;
      Pages: 6293 - 6303
      Abstract: In piezoelectric energy harvesting (PEH), interface circuits using synchronous switch actions, including synchronized charge extraction (CE) and/or bias-flip (BF), can achieve much higher energy harvesting (EH) capability, compared with the standard energy harvesting (SEH) bridge rectifier. In this article, a multistep charge extraction and voltage bias-flip (MCEBF) interface circuit is proposed to further enhance the harvesting capability under weakly coupling conditions. The EH enhancement is realized by reducing the dissipation in CE with multiple CE actions and simultaneously enlarging the extracted energy with a BF action. MCEBF can also generate positive and negative voltage rails via buck-boost topology to supply power for double-rail devices. The optimal control method of MCEBF is theoretically derived. In our experiment, under constant deflection excitation, the best MCEBF case offers 487%, 95%, and 49% more harvested power, compared with SEH, synchronous electric charge extraction (SECE), and parallel synchronized switch harvesting on inductor (P-SSHI) interface circuits, respectively. MCEBF also keeps the benefit of load independence as SECE does under weakly coupling conditions.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • An Enhanced Deadbeat Predictive Current Control of SPMSM With Linear
           Disturbance Observer

    • Free pre-print version: Loading...

      Authors: Xin Yuan;Shuangchun Xie;Jiahao Chen;Shuo Zhang;Chengning Zhang;Christopher H. T. Lee;
      Pages: 6304 - 6316
      Abstract: Deadbeat predictive current control (DPCC) with a linear disturbance observer (LDO) in the surface-mounted permanent magnet synchronous machine (SPMSM) has been widely applied in many applications due to better dynamic response performance and easy implementation. However, the evaluated lumped disturbances caused by current measurement noises, inverter nonlinearity, abrupt reference current, and initial inductance parameter mismatch can restrain the high-performance development. In order to handle this issue, an enhanced DPCC with LDO is proposed in this article, where a modified DPCC with the LDO model and the noninvasive inductance and inverter disturbance observer are developed. In this case, the initial inductance parameter mismatch and high-frequency disturbances effect on the DPCC with LDO is reduced, while the current measurement noises’ suppression is enhanced by the proposed LDO. The theoretical analysis has shown that the proposed DPCC with LDO has a better performance than the conventional DPCC with LDO. Also, the superiority of the proposed DPCC with LDO has been validated by an SPMSM drive test rig.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A Wireless Power Transfer System With Hybrid Control for Constant Current
           and Voltage Output

    • Free pre-print version: Loading...

      Authors: Zhihao Wei;Bo Zhang;Xujian Shu;Chao Rong;
      Pages: 6317 - 6331
      Abstract: This article proposes the wireless power transfer (WPT) system that achieves both inherent constant current and constant voltage (CV) outputs by switching the fixed frequency control strategy and the self-oscillating control strategy. Initially, the proposed system is analyzed by the $M$ model, and the transmission performance of the proposed WPT system under different control strategies is studied. The output voltage of the proposed system in the CV mode is not only independent of the load resistance but also irrespective of the coupling coefficient; hence, the system has a high misalignment tolerance. Moreover, a method for estimating parameters is presented, and this approach can monitor the load resistance and coupling coefficient only by detecting the primary side current, and the proposed system does not require wireless communication. The workflow of the system is designed. Finally, the feasibility of the proposed method is verified by the experimental results obtained from the laboratory prototype.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Parameter Identification Method With Dynamic Impedance Modulation for the
           DWPT System

    • Free pre-print version: Loading...

      Authors: Haowei Niu;Guocun Li;Jinghang Lu;Xuewei Pan;
      Pages: 6332 - 6344
      Abstract: A novel parameter identification method with dynamic impedance regulation is proposed to maintain constant output voltage of dynamic wireless power transfer (DWPT) system under varied loads and mutual inductance conditions. The resonant capacitor in the receiver side is replaced with a switched-controlled capacitor (SCC) structure, which enables the system to work under two operation modes. And then a comprehensive mathematical model is established according to these two modes to achieve the parameter identification. To avoid the deterioration of identification accuracy caused by the capacitors’ parameter drift, a dynamic impedance regulation method is introduced. The SCC is under dynamic closed-loop modulation to realize precious control of the equivalent capacitance of resonant capacitor in the receiver side. An experimental prototype is built in the laboratory, and the experimental results clearly demonstrate the accuracy of the proposed parameter identification.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Contactless Measurement of Current and Mutual Inductance in Wireless Power
           Transfer System Based on Sandwich Structure

    • Free pre-print version: Loading...

      Authors: Sheng Liu;Yue Feng;Wanying Weng;Jinghui Chen;Jiande Wu;Xiangning He;
      Pages: 6345 - 6357
      Abstract: The mutual inductance between the transmitter and receiver sides is critical for the efficiency of a wireless power transfer (WPT) system. This article proposes a novel online mutual inductance measurement method based on a local detection coil with a sandwich structure. The mutual inductance and the receiver current are obtained by measuring the induced voltage of the sandwich coil and the output voltage of the inverter, with contactless measurement from the receiver side. Using the ferrite substrate as the skeleton of the sandwich detection coil not only increases the differential mutual inductance between the receiver coil and the sandwich coil but also maintains the differential mutual inductance almost constant when horizontal misalignment occurs. Moreover, the differential mutual inductance is used to calculate the mutual inductance between the transmitter and receiver coils and the orthogonal eigenvalue expansion method is exploited to analyze the sandwich detection coil in a finite region. Then, the factors affecting the differential mutual inductance are analyzed and optimized, and a stable differential mutual inductance is obtained by formulating a standard coil design procedure. Finally, a prototype is built to verify the proposed method. The experimental results show that the differential mutual inductance remains almost constant when the horizontal misalignment reaches 50% of the outer radius of the transmitter/receiver coil, and the maximum calculated error of the detected mutual inductance is 2.18%.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Load-Independent Power-Repeater Capacitive Power Transfer System With
           Multiple Constant Voltage Outputs

    • Free pre-print version: Loading...

      Authors: Ting Chen;Chenwen Cheng;Hong Cheng;Cong Wang;Chunting Chris Mi;
      Pages: 6358 - 6370
      Abstract: In this article, a novel load-independent capacitive power transfer (CPT) system with multiple constant voltage (CV) outputs is proposed. The capacitive repeater unit is designed to enhance the power transfer capability, which contains four plates where two plates are used to receive power from its previous unit and the other two plates transfer power to the next unit. Electric coupling between the receiving and transmitting plates in the repeater unit can be eliminated by placing them perpendicularly and employing the split-inductor matching network. The load is connected with each capacitive repeater unit so that multiple loads can be powered simultaneously. Aluminum oxide ceramic is placed between the two adjacent units to enhance their electric coupling. The $L$ -LCL network is adopted to compensate each capacitive repeater unit. Thus, CV outputs can be achieved for all loads, which ensure the independent operation of each load. The output voltages and efficiency are analyzed when considering the parasitic resistances. Finally, a three-load experimental setup is built to verify the effectiveness of the proposed system with an efficiency of 93.21%.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Constant-Current and Constant-Voltage Output Using Hybrid Compensated
           Single-Stage Resonant Converter for Wireless Power Transfer

    • Free pre-print version: Loading...

      Authors: Jingyu Wang;Chunfang Wang;Shuo Zhang;Hao Yuan;Quanlei Zhang;Dongxue Li;
      Pages: 6371 - 6382
      Abstract: At present, single-stage wireless power transfer (WPT) resonant converter with boost bridgeless power-factor-correction (PFC) rectifier has not been promoted due to the rising voltage of dc-link and unstable output voltage of the converter. The compensation network with load-independent constant current output (CCO) and constant voltage output (CVO) characteristics cannot be analyzed in this converter due to the above problems. In order to solve these problems, a new asymmetric modulation method and the corresponding compensation network design method for single-stage WPT converter are proposed in this article. The proposed modulation method makes the voltage of dc link and the output voltage of single-stage WPT converter constant. Based on the new modulation method, the design method of the compensation network and the implementation of zero-voltage switching (ZVS) in single-stage WPT converter are proposed and analyzed in this article. Compared with the other WPT converters, the proposed scheme has advantages in efficiency and cost. Finally, the superiorities of the proposed circuit are verified by experiments.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • A 6.78-MHz Burst-Mode Controlled Inductive Wireless Power Transfer System
           for Biomedical Implants With Back-Channel Communication Eliminated Using
           Transmitter Q-Factor Detection

    • Free pre-print version: Loading...

      Authors: Usama Anwar;Zhaoyi Liu;Dejan Markovic;
      Pages: 6383 - 6395
      Abstract: This article presents an analysis and design of high-efficiency, 6.78-MHz burst-mode controlled inductive wireless power transfer system (WPT) with no back-channel communication between a transmitter (TX) and a receiver (RX). Power is transmitted in bursts between the TX and the RX, and the duty cycle of the burst is controlled through load modulation to control power flow between the TX and the RX. Extra back-channel traditionally used for TX–RX communication to control power flow is avoided by using inherent load modulation properties of the WPT circuit. It is demonstrated that the quality factor of the TX can be detected to eliminate the back-channel communication. Furthermore, only an extra switch is added in the RX power stage in series with the load to regulate the output voltage. The proposed WPT circuit can regulate output voltage against distance variation of up to 3 cm using 3-cm-diameter TX and RX coils and a load variation from full load to no load. A 330-mW prototype circuit for use in medical implants is designed, built, and tested. The proposed research advances the state-of-the-art WPT systems for use in resource-constrained biomedical implants.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Precise Configuration of Transmission Line Class-E Power Amplifier
           Operating at GHz Frequency

    • Free pre-print version: Loading...

      Authors: Chen Yang;Ke Jin;Dongqin Mao;Xirui Zhu;
      Pages: 6396 - 6404
      Abstract: Power amplifier (PA) is a core part of microwave power transmission (MPT) system. Featuring simple topology and theoretical 100% efficiency, class-E PA is widely discussed both in industry and academia. This article centers around the precise configuration of transmission line class-E PA operating at GHz frequency. Based on the conversion between lumped element topology and transmission line topology of class-E PA, the equal resistance surface-based configuration method is proposed. Specific configuration method for different types of matching network is analyzed according to the corresponding characteristics. Then, an L-type matching network-based class-E PA is designed in detail for the MPT system. Besides, extended application of the proposed method is discussed for different derivate topologies of class-E PA. Finally, a 2.5-GHz/10-W transmission line class-E PA is fabricated in the lab and the proposed configuration method is fully verified with experiments.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Create Change: IEEE Smart Village

    • Free pre-print version: Loading...

      Pages: 6405 - 6405
      Abstract: Advertisement.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
  • Connect. Support. Inspire

    • Free pre-print version: Loading...

      Pages: 6406 - 6406
      Abstract: Advertisement.
      PubDate: Oct. 2022
      Issue No: Vol. 10, No. 5 (2022)
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 18.232.56.9
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-