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  Subjects -> ELECTRONICS (Total: 207 journals)
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Journal of Power Electronics
Number of Followers: 6  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1598-2092 - ISSN (Online) 2093-4718
Published by Springer-Verlag Homepage  [2467 journals]
  • 71% Common-mode voltage suppression modulation strategy for indirect
           matrix converters

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      Abstract: Abstract Common-mode voltage (CMV) with a high amplitude and frequency is generated when an indirect matrix converter (IMC) is operating, which damages the motor winding insulation and accelerates motor aging. Existing IMC modulation methods can only suppress the CMV by 42.3%. However, this paper proposes a modulation strategy with a 71% reduction in the peak CMV. The proposed method selects active vectors based on the characteristics of the CMV amplitude under each of the active vectors. The rectifier stage selects two active vectors within each modulation sector. According to the sector where the input reference current vector is located, the inverter stage chooses active-voltage vectors whose corresponding peak CMV is 1/3 the minimum peak line voltage for modulation. Moreover, the CMV spikes caused by the dead zone effect are eliminated by reasonably arranging the switching sequence of the voltage vectors in the inverter stage. The proposed approach considerably lowers the peak CMV and has a good suppression effect on the amplitude of high-frequency CMV. Finally, experimental results illustrate the CMV reduction efficiency of the modulation strategy.
      PubDate: 2023-02-01
       
  • Stability investigation of phase disturbances in doubly-fed wind power
           systems using phase-locked synchronization

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      Abstract: Abstract Under weak grid conditions, there is a strong nonlinear coupling between phase-locked loops (PLLs) and the doubly-fed induction generators (DFIGs), and the influence of its dynamic characteristics on system stability cannot be ignored. For a system to be stable, the dynamic properties must be considered. First, based on instantaneous power theory, the sub-synchronous frequency component of power oscillation in a three-phase symmetrical system with the participation of a PLL is deduced. Second, the PLL transient stability is studied under two power grid structures. Third, to connect with the power grid model, a DFIG with a PLL structure is established, and the phase disturbance of the PLL is used as the excitation signal. In the rotor current inner loop and the voltage outer loop transfer processes, the PLL phase disturbance component plays a role. A d-axis structure block diagram of the current loop with the PLL phase disturbance component is constructed, and the disturbance transfer function is deduced. The influence mechanism of the PLL control parameters on system power oscillation is investigated. Finally, the modeling simulation verifies the validity of the theoretical analysis.
      PubDate: 2023-02-01
       
  • Improved adaptive iterative learning current control approach for IPMSM
           drives

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      Abstract: Abstract The paper presents an improved adaptive iterative learning current control approach for interior permanent magnet synchronous motor (IPMSM) drives, which greatly improves performance in both dynamic and steady-state scenarios. The proposed method includes three control terms: feedback control terms, which stabilize state errors and get them closer to zero; iterative learning control terms, which enhance transient performance by updating the control command signals according to the recorded data (i.e., the preceding input and state errors) so they get closer to zero; and adaptive-terms, which compensate for parameter variations. The proposed method offers a robust dynamic/steady-state response due to the above three terms, when compared to the conventional non-adaptive ILC, i.e., it is sensitive to parameter variations. Simulation and experimental analysis confirm the efficacy of the proposed method using PSIM software tools and an IPMSM test-bed. The proposed method demonstrates improvements in terms of its transient response (i.e., fast settling time with a smaller overshoot) and steady-state response (i.e., less THD along with reduced current ripples) when compared with conventional methods.
      PubDate: 2023-02-01
       
  • Reduced-order controller design for Cuk converters based on objective
           holographic feedback

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      Abstract: Abstract Since the Cuk converter is a non-minimum phase system with an unstable internal dynamic, it is challenging to employ control methods such as input–output linearization to ensure the closed-loop system stability. This paper proposes an objective holographic feedback nonlinear control (OHFNC) method without static deviation to regulate fourth-order Cuk converters. A Cuk converter operating in the continuous conduction mode is adopted, and the input inductor current and output capacitor voltage of the system are selected as control target quantities. The OHFNC method aims to configure a nonlinear system with poles near the equilibrium point, and place them in desired positions. The target quantities are separately constrained by feedback coefficients, which forces them to converge to their corresponding reference trajectories. Accordingly, an integration link is introduced to compensate for the reference current error when the system is heavily loaded. Finally, simulation and experimental results show that the OHFNC method has a stronger robustness and a faster transient response than fractional-order PIλ dual-loop control.
      PubDate: 2023-02-01
       
  • Anti-misalignment capability optimization for laminated magnetic couplers
           in wireless charging systems using balanced particle swarm optimization
           method

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      Abstract: Abstract To desensitize wireless charging systems (WCSs) to misalignment and to achieve a stable output voltage without using additional control methods, a laminated magnetic coupler (LMC) optimized by the balanced particle swarm optimization (BPSO) method is proposed to improve the performance of WCSs. First, the output characteristics of the LCC-S compensated WCS are analyzed to illustrate the working principle of the LMC. Next, the misalignment characteristics of the LMC, which employs the magnetic integration technique and coil self-decoupling method, are analyzed. Then, the operating principle of the BPSO method is analyzed and used to optimize the LMC in terms of the mutual inductance and anti-misalignment range. Finally, experimental results indicate that the optimized LMC achieves high-efficiency constant voltage charging within a reasonable horizontal misalignment range. When compared to commonly used methods (such as the exhaustive method) for optimizing magnetic couplers, the BPSO method avoids complex algorithms and a heavy computation burden.
      PubDate: 2023-02-01
       
  • Voltage equalization control of three-phase cascaded H-bridge multilevel
           rectifiers

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      Abstract: Abstract According to the structure and characteristics of a three-phase cascaded H-bridge (CHB) of a high-power multilevel converter, the problem of DC side voltage imbalance in practical applications and the disadvantage where the complexity of the traditional centralized control voltage equalization scheme increases rapidly with an increase of the number of modules both need to be solved. In addition, with the characteristic that distributed control is conducive to the expansion of the system to high-power and multi-module cascade, a new quasi-distributed equalization control strategy is proposed in this paper. The new equalization control strategy combines the traditional closed-loop control with the modulation ratio correction method. On the basis of the traditional closed-loop control, an equalization control module is added to realize a balanced output of the DC side voltage. The control of the equalization control module is simple and flexible, and the complexity of the overall control algorithm is independent of the number of modules. Finally, the correctness and reliability of the control method are verified by experiments.
      PubDate: 2023-02-01
       
  • Lifetime-based fault tolerant strategy for three-level hybrid ANPC
           inverters

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      Abstract: Abstract This paper presents a fault tolerant control that aims at improving the reliability of three-level hybrid ANPC inverters. Since the hybrid ANPC inverter consists of Si devices and SiC devices have a higher output quality and lower power losses, it has been considered in various power conversion industries. However, there still are concerns over its reliability since employing many power devices increased the risk of failure. Furthermore, the inverter is composed of a switching device and a DC-link capacitor, which mainly determine the reliability of the system. As one of the strategies to improve reliability, fault tolerant control methods have been intensively studied. However, applying the fault tolerant control increases the power losses of the switching device or the DC-link capacitor, which leads to earlier second failures. This paper proposes a lifetime-based fault tolerant strategy considering the remaining useful lifetime of the power device and DC-link capacitor, which increases the lifetime of the whole system. The validity and effectiveness of the proposed fault tolerant control method are verified through simulation and experimental results.
      PubDate: 2023-02-01
       
  • Parameter identification and SOC estimation of lithium-ion batteries based
           on AGCOA-ASRCKF

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      Abstract: Abstract The state of charge (SOC) is an important parameter in battery management systems (BMS), and its accuracy is very important. In this paper, a co-estimation with the adaptive global optimal guided coyote optimization algorithm and the adaptive square root cubature Kalman filter (AGCOA-ASRCKF) is used to perform the parameter identification and SOC estimation of a lithium-ion second-order RC model. The AGCOA effectively solves the problems where traditional heuristic algorithms tend to fall into local optimum and have a slow convergence speed. The AGCOA can accurately identify the parameters of the battery model. At the same time, when compared with the cubature Kalman filter, the ASRCKF introduces a square root filter and adds a residual sequence to adaptively update the covariance of the process noise and measurement noise, which improves the estimation accuracy of the SOC. The method proposed in this paper is verified by intermittent constant current test, dynamic stress test, and the federal urban driving schedule. Simulation results show that a high-precision battery model can be established by AGCOA-ASRCKF. In addition, the predicted value of the terminal voltage is basically consistent with the actual value. At the same time, the SOC estimation error can be controlled to within 1.5%, and the algorithm has good robustness and reliability in the presence of errors in the initial SOC.
      PubDate: 2023-02-01
       
  • DC-side admittance model of converters with constant power control
           considering DC-side voltage fluctuation

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      Abstract: Abstract In the stability analysis of DC (direct-current) power grids, AC (alternating current)/DC converters are usually treated as linear proportional amplifiers or inertial links. However, this approximation will have a considerable effect on the DC-side impedance model of a constant active power control converter and then affect the accuracy of the stability analysis of DC grids. In this paper, in view of the DC-side of the voltage fluctuations, the DC-side admittance model is established after the nonlinear relationship between the port voltage and the modulation signal function is determined. A comparison is made between the traditional modeling method and the proposed modeling method in the analysis of the phase–frequency characteristics and amplitude–frequency characteristics of the admittance. Results show that the proposed small-signal model can better fit the measured admittance in the low-frequency bands. The proposed admittance model in this paper is further applied to assess the small-signal stability of a DC grid. Finally, PSCAD/EMTDC simulation and lab-scaled prototype experiment are used to verify the correctness and effectiveness of the established admittance model. Results show that the small-signal model deduced in this paper can better fit and measure the admittance in the low-frequency band, and can more accurately judge the stability of the DC system.
      PubDate: 2023-02-01
       
  • Modulation method of parallel interleaved three-level inverter considering
           neutral point potential and phase current balance

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      Abstract: Abstract The capacity and equivalent switching frequency of parallel interleaved inverters can be increased, but there are problems with neutral point potential balance and parallel bridge circulating current. This paper regards the parallel three-level inverter as a five-level inverter and five-level space vector integrated modulation is applied. On this basis, a neutral-point potential control strategy based on the mid-point charge to calculate the adjustment factor k is proposed. By further meticulously partitioning specific sector regions, the selection method of redundant vectors in the switching sequence is optimized without increasing the switching times, and the midpoint voltage ripple is reduced. Then, the redundant state allocation in the process of splitting the five-level into three-level is used as a new degree of freedom to suppress the circulating current of the parallel bridge, therefore realizing the control of voltage and current sharing. Finally, simulation and experiments verify the correctness and effectiveness of the method.
      PubDate: 2023-02-01
       
  • Optimization of sideband electromagnetic vibration and comprehensive
           control performance of PMSMs based on improved vector control

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      Abstract: Abstract To effectively suppress the electromagnetic vibration generated by a permanent magnet motor at different frequency bands and to further improve the comprehensive control performance of the system, a new vector control strategy is proposed in this paper. The speed controller and current controller of the traditional vector control system of a permanent magnet synchronous motor (PMSM) are improved by means of an active disturbance rejection controller (ADRC) and a super-twisting sliding mode controller (STSMC). At the same time, random frequency space pulse width modulation (RFSVPWM) based on a periodic function is proposed to replace the traditional SVPWM. First, the expression of the radial electromagnetic force wave generated by motor supply current harmonics in low and medium frequency as well as high-frequency sideband is deduced by an analytical method, and the reason for the generation of the new radial electromagnetic force based on PI vector control is determined. Second, the ADRC, STSMC, and RFSVPWM are designed to suppress the power supply current harmonics and radial electromagnetic force components that greatly contribute to the electromagnetic vibration of the motor in different frequency bands. Finally, the superiority of the improved PMSM vector control system in terms of the comprehensive control performance and electromagnetic vibration is verified by multi-physics coupled finite element simulations.
      PubDate: 2023-02-01
       
  • Silicon carbide-based digitally controlled zero voltage switching
           dual-phase interleaved totem-pole PFC rectifier operating at high
           frequency

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      Abstract: Abstract An interleaved PFC rectifier reduces ripple current and a bridgeless PFC rectifier eliminates commutation loss. This study presents a dual-phase interleaved bridgeless totem-pole PFC rectifier that takes both the advantages. This rectifier operates in a variable frequency mode while achieving a zero voltage switching operation. In particular, four 650 V silicon carbide (SiC)-based transistors are applied to two boost circuits configured for a dual-phase interleaved operation. Two boost circuits operate at higher switching frequencies above 200 kHz due to the ZVS operation of the SiC-based transistors. A 500 W prototype board is implemented. The design issues of the totem-pole PFC rectifier are highlighted, and the digital control methods are applied to address them. In addition, this work investigates the conducted EMI noise of the circuit that operates with a dual-boost interleaved method at the higher switching frequencies. A single-stage input EMI filter is designed based on the analysis. Lastly, the superior switching characteristics of the SiC-based transistor are confirmed, and the overall performance of the prototype board is evaluated.
      PubDate: 2023-02-01
       
  • Predictive direct torque control of permanent magnet synchronous motors
           using deadbeat torque and flux control

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      Abstract: Abstract In consideration of the shortcomings of the large torque and flux ripples in direct torque control (DTC), and the insufficient utilization of the duty cycle module in traditional DTC based on the duty cycle modulation of PMSMs, a DTC method based on deadbeat control of the torque and flux is proposed in this paper. In the synchronous rotation, coordinate system positioned with the stator flux vector, the reference voltage vector is calculated in accordance to the deadbeat control method. Six virtual voltages are constructed in such a manner that two adjacent basic voltage vectors are evenly divided in one control cycle. The effective voltage vectors are expanded to 12. The effective voltage vector closest to the phase angle of the reference voltage vector is determined to be the optimal voltage vector. Then, the duty cycle is introduced to further reduce the error between the final output voltage vector and the voltage vector required by the system. Simulation comparisons are carried out for DTC, traditional DTC based on duty cycle modulation, and the proposed DTC. The obtained simulation results demonstrate that the proposed DTC can effectively suppress both torque ripple and flux ripple, improve the utilization rate of the duty cycle module, and reduce the stator current distortion rate.
      PubDate: 2023-02-01
       
  • Inverter average input power estimation algorithm in low-frequency
           modulation index operation of permanent magnet synchronous motors

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      Abstract: Abstract This paper presents an inverter average input power estimation algorithm in the low-frequency modulation index such as a low sampling to operating frequency ratio. When the current sampling frequency to operating frequency is low, the error between the sampled phase current and the average phase current is large. This results in an error of the inverter average input power estimation, because it is calculated with the sampled phase current. Thus, in this paper, the average phase currents are calculated for every voltage vector duration within a current sampling period. The average phase currents are multiplied by the phase voltages to estimate the inverter average input power. Then, the inverter average input power is estimated as the sum of the three phases in the active voltage durations. Simulation and experimental results are presented to verify the proposed inverter average input power estimation.
      PubDate: 2023-02-01
       
  • Hardware-simulator development and implementation of battery charger for
           personal mobility devices

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      Abstract: Abstract Recently, research on personal mobility devices (PMDs) such as electric motorcycles, electric bikes, electric scooters, and electric wheelchairs has been globally proceeded. However, PMDs have a disadvantage since the required battery voltage is different depending on the type of PMD. Therefore, to charge the battery of a PMD, an individual battery charger should be used depending on type of PMD which reduces industrial usability and availability of PMDs. To solve this problem, a battery charger capable of responding to various battery voltages is required. In this paper, the hardware-simulator development of a battery charger that can respond to the various battery voltages of PMDs is proposed, and it consists of a boost converter, a half-bridge series resonant converter, and a buck converter. Additionally, this paper presents a control strategy for use in the proposed hardware simulator. The effectiveness of the proposed hardware simulator and its control strategy are verified by experimental results.
      PubDate: 2023-02-01
       
  • Wide input range non-isolated three-port converters for stand-alone PV
           storage power systems

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      Abstract: Abstract To address the instability of the input voltage of photovoltaic (PV) in a stand-alone PV storage power generation system, a wide input range non-isolated three-port converter that can operate in a range that is greater than and less than the voltage of the storage port is proposed in this paper. The proposed converter can realize the energy flow and power balance between the PV, the battery, and the load. This converter is a combination of conventional Buck, Boost, and Buck–Boost converters with a four-switch bi-directional Buck–Boost converter (FSBB). The FSBB is used to connect the PV and battery ports, which can reduce the voltage constraint of the storage port on the PV port voltage, and broaden the selection of the voltage levels of the storage port to meet the application requirements of the PV port with a wide voltage input. In this paper, an experimental prototype is designed by combining the Boost converter and the FSBB converter. Finally, the correctness of the theoretical analysis and the feasibility of the energy management strategy of the converter are verified through experimental results.
      PubDate: 2023-02-01
       
  • 22 kW high-efficiency IPT system for wireless charging of electric
           vehicles

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      Abstract: Abstract This work presents a 22 kW class high-efficiency inductive power transfer (IPT) system for wirelessly charging electric vehicles with 800 V class batteries. Ansys Maxwell simulation is conducted by analyzing the international standard IEC61980-3 to design and implement a 22 kW class transceiver. The battery load is modeled from the charging profile of a 22 kW and 800 V battery to select the optimal IPT topology. Six types of impedance compensation circuits are theoretically analyzed based on the above-mentioned experimental setup, and the optimal design of resonance parameters is designed. The ultimately selected IPT topology based on the optimal design results for each topology is an LCC–CCL structure with constant current output characteristics. A 22 kW class LCC–CCL structure IPT system capable of wirelessly charging an 800 V class battery is designed and manufactured, and experiments are conducted to verify its performance in all alignments of the transceiver and the entire battery charging profile. Based on the results of the theoretical analyses and experiments, the proposed IPT system confirms that the zero-voltage switching operation is possible at a fixed switching frequency of 83 kHz. In the 22 kW load condition, the maximum efficiency of 95.7% is achieved in the center alignment condition, and the IPT system achieves a high efficiency of 94% or more even in the maximum misalignment condition.
      PubDate: 2023-02-01
       
  • 6.78 MHz loosely coupled inductive wireless power transfer with
           series–parallel resonators

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      Abstract: Abstract In a recent trend, near distance wireless power transfer (WPT) for low-power applications has increased exponentially. However, issues such as high harmonic content at the input side of the transmission coil and very low WPT efficiency are persistent. Therefore, a new magnetic resonance WPT (MRWPT) system has been proposed to overcome the aforementioned issues. This paper introduces an LC compensated half-bridge class-D inverter, which minimizes the harmonic content from the input source and makes the MOSFET of the inverter perform zero voltage switching. Simultaneously, a matching capacitor is connected between the resonant coil and the compensated inverter to suppress the reactive power loss. In addition, a series–parallel (SP) structured resonance coil has been introduced for low-power applications due to its high-efficiency WPT capability in near and mid-range distances. The introduced structure acts as a current source-transmitting resonator and a voltage source receiving resonator, which ensures the guaranteed resonance regardless of load variations. The performance of the proposed MRWPT system is analyzed using two-port scattering or S-parameter in the high-frequency structure simulation (HFSS) of ANSYS software. To validate the performance of the simulated system, an experimental 7 W setup has been designed to charge a mobile device.
      PubDate: 2023-02-01
       
  • Hybrid passivity-based control for stability and robustness enhancement in
           DC microgrids with constant power loads

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      Abstract: Abstract In a DC microgrid, the negative damping characteristics of a constant power load can deteriorate the stability of the whole system. To improve the robustness and stability of the DC microgrid, a hybrid passivity-based control of damping injection is presented in this paper. The stability of the closed-loop system is ensured by the energy dissipation property of the passivity-based control. A proportional-integral controller is integrated with the passivity-based controller to form a hybrid passivity-based control to improve control robustness. A small-signal model of a DC power system with constant power load is derived in detail, and the stability of the system is analyzed with the Lyapunov eigenvalue method. The proposed hybrid passivity-based control provides the system with a faster recovery and a larger power boundary when compared with the typical voltage-current dual-loop control. First, the proposed control is verified by simulation of the DC power system based on MATLAB/Simulink, and the feasibility and superiority of the proposed control are further verified by hardware-in-loop (HIL) experiments based on real-time laboratory (RT-Lab) and a TI DSP TMS320 F28335.
      PubDate: 2023-02-01
       
  • High-frequency planar transformer optimal design and analysis

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      Abstract: Abstract Due to the rapid development of modern industry, there is an increasing demand for isolated switching power supplies (SMPS) with a high efficiency and a high power density. Magnetic components, which occupy most of the converter volume, have been a key bottleneck in achieving high power density. This paper presents an optimal design method for high power density planar transformers. Applying the principle of flux cancellation, a matrix transformer that originally needed an independent magnetic core was integrated into a single magnetic core to reduce the volume of the core. Meanwhile, a loss model of the transformer is established, and an optimized design method of the winding structure is given according to that model to further reduce the winding loss of the transformer. Finally, an LLC converter with a resonant frequency of 1 MHz is designed to verify the practical performance of the proposed transformer.
      PubDate: 2023-02-01
       
 
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