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  Subjects -> ELECTRONICS (Total: 146 journals)
Advanced Electromagnetics     Open Access   (9 followers)
Advances in Biosensors and Bioelectronics     Open Access   (1 follower)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (4 followers)
Advances in Microelectronic Engineering     Open Access   (1 follower)
Advances in Power Electronics     Open Access   (7 followers)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (46 followers)
American Journal of Electrical and Electronic Engineering     Open Access   (7 followers)
Annals of Telecommunications     Hybrid Journal   (3 followers)
APL : Organic Electronics and Photonics     Hybrid Journal   (1 follower)
APSIPA Transactions on Signal and Information Processing     Open Access   (2 followers)
Archives of Electrical Engineering     Open Access   (8 followers)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (5 followers)
Bell Labs Technical Journal     Hybrid Journal   (8 followers)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (14 followers)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (11 followers)
Biomedical Instrumentation & Technology     Full-text available via subscription   (4 followers)
Broadcasting, IEEE Transactions on     Hybrid Journal   (5 followers)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (1 follower)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (12 followers)
China Communications     Full-text available via subscription  
Circuits and Systems     Open Access   (6 followers)
Consumer Electronics Times     Open Access   (3 followers)
Control Systems     Hybrid Journal   (18 followers)
Electronic Markets     Hybrid Journal   (5 followers)
Electronic Materials Letters     Hybrid Journal   (2 followers)
Electronics     Open Access   (3 followers)
Electronics and Communications in Japan     Hybrid Journal   (4 followers)
Electronics Letters     Hybrid Journal   (15 followers)
Embedded Systems Letters, IEEE     Hybrid Journal   (14 followers)
EURASIP Journal on Embedded Systems     Open Access   (8 followers)
EURASIP Journal on Image and Video Processing     Open Access   (6 followers)
EURASIP Journal on Wireless Communications and Networking     Open Access   (8 followers)
Foundations and TrendsĀ® in Communications and Information Theory     Full-text available via subscription   (5 followers)
Foundations and TrendsĀ® in Signal Processing     Full-text available via subscription   (4 followers)
Frequenz     Full-text available via subscription   (1 follower)
Frontiers of Optoelectronics     Hybrid Journal  
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (19 followers)
Haptics, IEEE Transactions on     Hybrid Journal   (4 followers)
IEEE Consumer Electronics Magazine     Full-text available via subscription   (7 followers)
IEEE Electromagnetic Compatibility Magazine     Full-text available via subscription   (2 followers)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (3 followers)
IEEE Journal of the Electron Devices Society     Open Access   (1 follower)
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (9 followers)
IEEE Transactions on Automatic Control     Hybrid Journal   (18 followers)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (10 followers)
IEEE Transactions on Electromagnetic Capability     Hybrid Journal   (10 followers)
IEEE Transactions on Electron Devices     Hybrid Journal   (6 followers)
IEEE Transactions on Information Theory     Hybrid Journal   (12 followers)
IEEE Transactions on Power Electronics     Hybrid Journal   (10 followers)
IEICE - Transactions on Electronics     Full-text available via subscription   (7 followers)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (7 followers)
IET Power Electronics     Hybrid Journal   (7 followers)
IET Wireless Sensor Systems     Hybrid Journal   (5 followers)
IETE Journal of Education     Open Access   (2 followers)
IETE Journal of Research     Open Access   (5 followers)
IETE Technical Review     Open Access   (1 follower)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (9 followers)
Industry Applications, IEEE Transactions on     Hybrid Journal   (5 followers)
Informatik-Spektrum     Hybrid Journal  
Instabilities in Silicon Devices     Full-text available via subscription  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (1 follower)
International Journal of Advanced Electronics and Communication Systems     Open Access   (3 followers)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (18 followers)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (1 follower)
International Journal of Aerospace Innovations     Full-text available via subscription   (10 followers)
International Journal of Applied Electronics in Physics & Robotics     Open Access  
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (3 followers)
International Journal of Computational Vision and Robotics     Hybrid Journal   (4 followers)
International Journal of Computer & Electronics Research     Full-text available via subscription   (2 followers)
International Journal of Control     Hybrid Journal   (9 followers)
International Journal of Electronics     Hybrid Journal   (2 followers)
International Journal of Electronics & Data Communication     Open Access   (3 followers)
International Journal of Electronics and Telecommunications     Open Access   (3 followers)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (1 follower)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (1 follower)
International Journal of Nano Devices, Sensors and Systems     Open Access   (1 follower)
International Journal of Nanoscience     Hybrid Journal   (1 follower)
International Journal of Numerical Modelling:Electronic Networks, Devices and Fields     Hybrid Journal   (2 followers)
International Journal of Power Electronics     Hybrid Journal   (3 followers)
International Journal of Power Management Electronics     Open Access  
International Journal of Review in Electronics & Communication Engineering     Open Access   (1 follower)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (1 follower)
International Journal of Systems, Control and Communications     Hybrid Journal   (2 followers)
International Journal on Communication     Full-text available via subscription   (6 followers)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (11 followers)
ISRN Communications and Networking     Open Access   (4 followers)
ISRN Electronics     Open Access   (1 follower)
ISRN Signal Processing     Open Access  
Journal of Advanced Dielectrics     Open Access   (1 follower)
Journal of Artificial Intelligence     Open Access   (5 followers)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (1 follower)
Journal of Electrical and Electronics Engineering Research     Open Access   (1 follower)
Journal of Electrical Bioimpedance     Full-text available via subscription   (2 followers)
Journal of Electrical Engineering & Electronic Technology     Full-text available via subscription   (1 follower)
Journal of Electromagnetic Analysis and Applications     Open Access   (3 followers)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (2 followers)
Journal of Electronic Design Technology     Full-text available via subscription  
Journal of Electronics (China)     Hybrid Journal   (2 followers)

        1 2 | Last

IEEE Transactions on Power Electronics    [12 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0885-8993
     Published by Institute of Electrical and Electronics Engineers (IEEE) Homepage  [171 journals]   [SJR: 3.308]   [H-I: 111]
  • IEEE Power Electronics Society Information
    • Pages: C3 - C3
      Abstract: Provides a listing of current committee members and society officers.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • IEEE Transactions on Power Electronics publication information
    • Pages: C2 - C2
      Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Table of contents
    • Pages: C1 - C4
      Abstract: Presents the table of contents for this issue of the periodical.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Editorial: Special Issue on Wide Bandgap Power Devices and Their
           Applications, 2014
    • Authors: Nee; H.-P.;Kolar, J.W.;Friedrichs, P.;Rabkowski, J.;
      Pages: 2153 - 2154
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A Survey of Wide Bandgap Power Semiconductor Devices
    • Authors: Millan; J.;Godignon, P.;Perpina, X.;Perez-Tomas, A.;Rebollo, J.;
      Pages: 2155 - 2163
      Abstract: Wide bandgap semiconductors show superior material properties enabling potential power device operation at higher temperatures, voltages, and switching speeds than current Si technology. As a result, a new generation of power devices is being developed for power converter applications in which traditional Si power devices show limited operation. The use of these new power semiconductor devices will allow both an important improvement in the performance of existing power converters and the development of new power converters, accounting for an increase in the efficiency of the electric energy transformations and a more rational use of the electric energy. At present, SiC and GaN are the more promising semiconductor materials for these new power devices as a consequence of their outstanding properties, commercial availability of starting material, and maturity of their technological processes. This paper presents a review of recent progresses in the development of SiC- and GaN-based power semiconductor devices together with an overall view of the state of the art of this new device generation.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Effects of Gate Field Plates on the Surface State Related Current Collapse
           in AlGaN/GaN HEMTs
    • Authors: Huang; H.;Liang, Y.C.;Samudra, G.S.;Chang, T.-F.;Huang, C.-F.;
      Pages: 2164 - 2173
      Abstract: During off-state, the influence of surface-trapped electron charges induced by high-field stress near the gate electrode of AlGaN/GaN power high-electron mobility transistor devices causes a reduction in two-dimensional electron gas (2DEG) carrier density at the heterointerface. In a pulse turn-on operation, the weakened 2DEG channel results in a higher on-state conduction resistance during the transient, known as the current collapse phenomenon. The phenomenon increases the switching loss by a higher on-state resistance and prolonged turn-on transition time, thus limits the device operating frequency range. In this paper, such a phenomenon is modeled, analyzed by Sentaurus TCAD simulation, and verified by the laboratory measurement data, with the emphasis on the influence of field plates toward the current collapse. The spatial distributions of trapped electrons and excess free electrons along the AlGaN surface are modeled and analyzed to arrive at the quantitative relationships among the trapped electron density, on-resistance increase, and the electric field distribution which provide a reliable criterion for current collapse reduction. It was found that, with a proper field plate design, it is possible to achieve an improvement on transient on-state resistance and the current recovery time.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Design and Performances of 4H-SiC Bipolar Mode Field Effect Transistor
    • Authors: Bellone; S.;Di Benedetto, L.;
      Pages: 2174 - 2179
      Abstract: An original design of 4H polytype of silicon carbide (4H-SiC) bipolar-mode field-effect transistors (BMFETs), which combines the on-state operation of silicon version with the off-state behavior of SiC-VJFETs (vertical junction field-effect transistor), is analyzed by numerical simulations. Using the physical parameters extracted from the previous experimental analysis, this paper shows the feasibility of 4H-SiC BMFETs to manage drain current densities as high as 500 A/cm $^{2}$ with a current gain of 50 and to sustain blocking voltage of 2.1 kV. Comparisons with the existing 4H-SiC power transistors, like bipolar junction transistors (BJTs), VJFETs, and double-diffusive metal–oxide–semiconductor FETs, show that, besides a thermal stability in the examined range 300–523 K, BMFET exhibits the low on-resistance of BJTs and can operate at the high frequencies of power FETs.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Analysis and Experimental Verification of the Influence of Fabrication
           Process Tolerances and Circuit Parasitics on Transient Current Sharing of
           Parallel-Connected SiC JFETs
    • Authors: Lim; J.-K.;Peftitsis, D.;Rabkowski, J.;Bakowski, M.;Nee, H.-P.;
      Pages: 2180 - 2191
      Abstract: Operation of parallel-connected 4H-SiC vertical junction field effect transistors (VJFETs) from SemiSouth is modeled using numerical simulations and experimentally verified. The unbalanced current waveforms of parallel-connected VJFETs are investigated with respect to the spread in the critical parameters of the device structure and to the influence of the parasitic inductances in the measurement circuit. The device structures are reconstructed based on scanning electron microscopy (SEM) analysis, electrical characterization, and device simulations. The doping concentration and profile depth of a p-grid formed by angular implantation are studied as main contributors that influence the variation of the on-state characteristics, and the threshold voltage of the experimental devices. It has been shown elsewhere that similar differences in p-grid also lead to differences in gate–source breakdown voltage. The switching performance of the parallel-connected JFETs is measured using single and double gate drivers in a double-pulse test and compared with simulations. The switched current and voltage waveforms from measurements are reproduced in simulation by introducing the parasitics. From the analysis, it is found that reasonable differences in doping levels and profiles of the p-grid give rise to significant differences in device parameters. However, even with these parameter differences and circuit asymmetries, it is possible to successfully operate parallel-connected VJFETs of this type.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • 1000-H Evaluation of a 1200-V, 880-A All-SiC Dual Module
    • Authors: Salem; T.E.;Wood, R.A.;
      Pages: 2192 - 2198
      Abstract: The commercial availability of silicon-carbide (SiC) power devices began over a decade ago with the introduction of SiC diodes and has expanded in complexity the past few years to include the offering of SiC transistors and power modules. Recently, characterization of a 1200-V, 800-A all-SiC dual module designed for large-scale electric military vehicle applications has been reported. This paper expands on the previous work by presenting details and results obtained from a long-term evaluation of a similar module. The module has successfully operated in an experimental circuit at a switching frequency of 10 kHz while running vehicle load profiles for over 1000 h and exhibited little change in device characteristics. Of all measured characteristics, none had a significant unfavorable change greater than 10% from its initial value. The 1000 h of circuit operation represents 11 783 miles of use or over half of the expected lifecycle in a military vehicle traction inverter.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Trapping and Reliability Assessment in D-Mode GaN-Based MIS-HEMTs for
           Power Applications
    • Authors: Meneghini; M.;Bisi, D.;Marcon, D.;Stoffels, S.;Van Hove, M.;Wu, T.-L.;Decoutere, S.;Meneghesso, G.;Zanoni, E.;
      Pages: 2199 - 2207
      Abstract: This paper reports on an extensive analysis of the trapping processes and of the reliability of experimental AlGaN/GaN MIS-HEMTs, grown on silicon substrate. The study is based on combined pulsed characterization, transient investigation, breakdown, and reverse-bias stress tests, and provides the following, relevant, information: 1) the exposure to high gate–drain reverse-bias may result in a recoverable increase in the on-resistance $(R_{rm ON})$ , and in a slight shift in threshold voltage; 2) devices with a longer gate–drain distance show a stronger increase in $R_{rm ON}$ , compared to smaller devices; 3)current transient measurements indicate the existence of one trap level, with activation energy of 1.03 ± 0.09 eV; and 4) we demonstrate that through the improvement of the fabrication process, it is possible to design devices with negligible trapping. Furthermore, the degradation of the samples was studied by means of step-stress experiments in off-state. Results indicate that exposure to moderate–high reverse bias (< 250 V for $L_{rm GD}$ = 2 μm) does not induce any measurable degradation, thus confirming the high reliability of the analyzed samples. A permanent degradation is detected only for very high reverse voltages (typically, $V_{rm DS}$ = 260–265 V, on a device with $L_{rm GD}$ = 2 μm stressed with $V_{rm GS}$ = – 8 V) and consists of a rapid increase in gate leakage current, followed by a catastrophic failure. EL- measurements and microscopy investigation revealed that degradation occurs close to the gate, in proximity of the sharp edges of the drain contacts, i.e., in a region where the electric field is maximum.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Analytical Loss Model of High Voltage GaN HEMT in Cascode Configuration
    • Authors: Huang; X.;Li, Q.;Liu, Z.;Lee, F.C.;
      Pages: 2208 - 2219
      Abstract: This paper presents an accurate analytical model to calculate the power loss of a high voltage Gallium Nitride high electron mobility transistor (GaN HEMT) in cascode configuration. The proposed model considers the package and PCB parasitic inductances, the nonlinearity of the junction capacitors, and the transconductance of the cascode GaN transistor. The switching process is illustrated in detail, including the interaction of the low voltage Si MOSFET and the high voltage GaN HEMT in cascode configuration. The switching loss is obtained by solving the equivalent circuits during the switching transition. The analytical results show that the turn-on loss dominates in hard-switching conditions while the turn-off loss is negligible, due to the intrinsic current source driving mechanism. The accuracy of the proposed model is validated by numerous experimental results. The results of both the analytical model and experiments suggest that soft-switching is critical for high voltage GaN in high-frequency high-efficiency applications.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Datasheet Driven Silicon Carbide Power MOSFET Model
    • Authors: Mudholkar; M.;Ahmed, S.;Ericson, M.N.;Frank, S.S.;Britton, C.L.;Mantooth, H.A.;
      Pages: 2220 - 2228
      Abstract: A compact model for SiC Power MOSFETs is presented. The model features a physical description of the channel current and internal capacitances and has been validated for dc, CV, and switching characteristics with measured data from a 1200-V, 20-A SiC power MOSFET in a temperature range of 25 $^{circ }$ C to 225 $^{circ }$ C. The peculiar variation of on-state resistance with temperature for SiC power MOSFETs has also been demonstrated through measurements and accounted for in the developed model. In order to improve the user experience with the model, a new datasheet driven parameter extraction strategy has been presented which requires only data available in device datasheets, to enable quick parameter extraction for off-the-shelf devices. Excellent agreement is shown between measurement and simulation using the presented model over the entire temperature range.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Improved Modeling of Medium Voltage SiC MOSFET Within Wide Temperature
    • Authors: Sun; K.;Wu, H.;Lu, J.;Xing, Y.;Huang, L.;
      Pages: 2229 - 2237
      Abstract: An improved model of medium voltage (1200 V) silicon carbide (SiC) MOSFET based on PSpice is proposed in this paper, which is suitable for wide temperature range applications especially at low temperature. The static characteristics of SiC MOSFET are described by introducing temperature-dependent voltage source and current source. The effect of negative turn-off gate drive voltage is also taken into account in the modeling. In order to reflect the low-temperature characteristics of SiC MOSFET accurately, low temperature (−25 °C) measurements are carried out, which provide the modeling basis. The determinations of key parameters in the model are analyzed in detail, including the on-state resistor, internal gate resistor, temperature dependent sources, and some capacitors. The proposed model is verified by the experimental tests on a buck converter prototype at different input voltages, input currents, and temperatures. Simulation results on the proposed model coincide well with the experimental test results, in terms of switching waveforms and power losses even at low temperature (−25 °C). These results demonstrate that the proposed model exhibits high accuracy within wide temperature range.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Characterization and Scalable Modeling of Power Semiconductors for
           Optimized Design of Traction Inverters with Si- and SiC-Devices
    • Authors: Merkert; A.;Krone, T.;Mertens, A.;
      Pages: 2238 - 2245
      Abstract: Silicon carbide (SiC) based power semiconductors are expected to contribute to an increase in inverter efficiency, switching frequencies, maximum permissible junction temperature, and system power density. This paper presents a comparison of silicon (Si) and SiC device technologies for the use in hybrid electric vehicle traction inverters. SiC-JFETs and SiC-MOSFETs are characterized and a scalable loss and scalable thermal modeling approach is used to find the optimum chip area for each Si or SiC traction inverter. This procedure also provides a proper technical comparison of the semiconductor technologies. The progressed simulations using standardized drive cycles and thermal–electrical coupled semiconductor models permit an inverter performance evaluation close to real load situations, leading to an improved estimation of the benefit which can be expected from systems utilizing SiC technology. This paper concludes that the SiC devices can lead to a reduction in chip area and semiconductor losses by more than 50% at the same time in hard switching applications with partial load dominated mission profiles.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Modeling of a Buck Converter With a SiC JFET to Predict EMC Conducted
    • Authors: Rondon-Pinilla; E.;Morel, F.;Vollaire, C.;Schanen, J.-L.;
      Pages: 2246 - 2260
      Abstract: The reduced switching times of silicon carbide (SiC) components compared to Si components in similar conditions are a great advantage from the point of view of efficiency, but, due to the high dv/dt and di/dt, conducted electromagnetic emissions are increased. Therefore, the availability of a method which can predict these emissions is increasingly necessary. To the best of the authors’ knowledge, a model that can predict differential mode as well as common mode for a converter including sic devices has not yet been published. the novelty of the work presented here is the integration of different modeling approaches to form a circuit model of a SiC-based buck dc–dc converter working in frequency range from 40 Hz to 30 MHz. A modeling approach of the passive parts of the converter is presented. Then, the model obtained is used in simulations to predict the drain-to-source voltage and the drain current for the JFET. Conducted emissions received by the line impedance stabilization network are also computed. Simulation results are compared to measurements for different duty cycles and different gate resistors in the time and frequency domains. A good agreement is obtained. In the frequency domain, in all cases, differences are less than 5 dBμV up to 30 MHz excepted in the JFET source current.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Thermomechanical Assessment of Die-Attach Materials for Wide Bandgap
           Semiconductor Devices and Harsh Environment Applications
    • Authors: Navarro; L.A.;Perpina, X.;Godignon, P.;Montserrat, J.;Banu, V.;Vellvehi, M.;Jorda, X.;
      Pages: 2261 - 2271
      Abstract: Currently, the demand by new application scenarios of increasing operating device temperatures in power systems is requiring new die-attach materials with higher melting points and suitable thermomechanical properties. This makes the die-attach material selection, die-attaching process, and thermomechanical evaluation a real challenge in nowadays power packaging technology. This paper presents a comparative analysis of the thermomechanical performance of high-temperature die-attach materials (sintered nano-Ag, AuGe, and PbSnAg) under harsh thermal cycling tests. This study is carried out using a test vehicle formed by four dice (considering Si and SiC semiconductors) and Cu substrates. Thermally cycled test vehicles have been thermomechanically evaluated using die-shear tests and acoustic microscopy inspections. Besides, special attention is paid to set up a nano-Ag sintering process, in which the effects of sintering pressure or substrate surface state (roughness and surface activation) on the die-attach layer are analyzed. As a main result, this study shows that the best die-attach adherence is obtained for nano-Ag when pressure is applied on the dice (using a specifically designed press) during the sintering process (11 MPa provided die-shear forces of 53 kgf). However, this die-attach presents a faster thermomechanical degradation under harsh thermal cycling tests than other considered high-temperature die-attach materials (AuGe and PbSnAg) and PbSnAg shows the best thermomechanical performances.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • The Investigation of a 6.5-kV, 1-kA SiC Diode Module for Medium Voltage
    • Authors: Filsecker; F.;Alvarez, R.;Bernet, S.;
      Pages: 2272 - 2280
      Abstract: This paper introduces a 6.5-kV 1-kA SiC PiN diode module for megawatt-range medium voltage converters. The analysis comprises a short description of the die and module technology and a device characterization. The effects of di/dt and temperature variation, as well as parasitic oscillations are discussed. A comparison of the results with a commercial Si diode (6.5 kV and 1.2 kA) is included. In the last section, an estimation of maximum converter output power, maximum switching frequency, losses and efficiency in a 3L-NPC converter operating with SiC and Si diodes is presented. The analyzed diode module exhibits a very good performance regarding switching loss reduction, which allows an increase of at least 16% in the output power of a 6-MVA converter. Alternatively, the switching frequency can be increased by 46%.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Evaluation of Encapsulation Materials for High-Temperature Power Device
    • Authors: Locatelli; M.-L.;Khazaka, R.;Diaham, S.;Pham, C.-D.;Bechara, M.;Dinculescu, S.;Bidan, P.;
      Pages: 2281 - 2288
      Abstract: High-temperature power electronics represent an increasing demand. Higher power density or severe ambient temperature applications become the trend, while silicon carbide components with 250–300 °C $T_{rm jmax}$ are emerging. Among materials used in high-voltage power module, soft encapsulants play a significant role in improving both semiconductor die and module package voltage ratings, especially under enhanced electrical and thermal constraints. In operation close to their upper temperature limit, two silicone materials were selected among the most thermally stable soft insulators available today. Up to 300 °C, dielectric properties and their stability under isothermal aging in air ambient tests were characterized. The gel, tested using sandwich structures, exhibits cracking of its exposed-to-air face, at an aging temperature as low as 250 °C after less than 100 h. The elastomer, tested as free films, presents no cracking, no degraded electrical characteristics, and a 6 % relative mass loss, after 500 h aging. Moreover, the elastomer insulating properties, at low and high electric field, remains stable up to 300 °C (short-term tests), contrary to the gel which shows a strong increase in dc electrical conductivity. So the elastomer shows promising properties for improved encapsulation performance at 250 °C, to be further investigated in package configurations.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Development of Advanced All-SiC Power Modules
    • Authors: Liang; Z.;Ning, P.;Wang, F.;
      Pages: 2289 - 2295
      Abstract: A thermally integrated packaging structure for an all silicon carbide (SiC) power module was used to realize highly efficient cooling of power semiconductor devices through direct bonding of the power stage and a cold baseplate. The prototype power modules composed of SiC metal-oxide-semiconductor field-effect transistors and Schottky barrier diodes demonstrate significant improvements such as low-power losses and low-thermal resistance. Direct comparisons to their silicon counterparts, which are composed of insulated gate bipolar transistors and PiN diodes, as well as conventional thermal packaging, were experimentally performed. The advantages of this SiC module in efficiency and power density for power electronics systems have also been identified, with clarification of the SiC attributes and packaging advancements.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A 3600 V/80 A Series--Parallel-Connected Silicon Carbide MOSFETs Module
           With a Single External Gate Driver
    • Authors: Wu; X.;Cheng, S.;Xiao, Q.;Sheng, K.;
      Pages: 2296 - 2306
      Abstract: In this paper, a new series connection topology is introduced for silicon carbide (SiC) MOSFETs. In the topology, with a single external gate drive, three series-connected SiC MOSFETs are synchronously driven. The operating principle of the proposed topology is analyzed and presented. In order to improve the current capability of the module, parallel connection of two SiC devices are also demonstrated. A 3600 V/80 A series–parallel-connected configuration with three rows in a series and two branches in parallel is constructed with six 1200 V/40 A discrete SiC MOSFETs. Switching behavior of the configuration is completed at 2300 V/78 A. Experimental results verify the validity and feasibility of the proposed topology. Analysis based on experimental results for the circuit switching speed and switching losses is given. Finally, such a series–parallel-connected circuit is integrated in a SiC MOSFETs module, capable of 3600 V/80 A. The switching characteristics of the module are compared to the discrete configuration.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A 1200-V, 60-A SiC MOSFET Multichip Phase-Leg Module for High-Temperature,
           High-Frequency Applications
    • Authors: Chen; Z.;Yao, Y.;Boroyevich, D.;Ngo, K.D.T.;Mattavelli, P.;Rajashekara, K.;
      Pages: 2307 - 2320
      Abstract: In this paper, a high-temperature, high-frequency, wire-bond-based multichip phase-leg module was designed, fabricated, and fully tested. Using paralleled Silicon Carbide (SiC) MOSFETs, the module was rated at 1200 V and 60 A, and was designed for a 25-kW three-phase inverter operating at a switching frequency of 70 kHz, and in a harsh environment up to 200 °C, for aircraft applications. To this end, the temperature-dependent characteristics of the SiC MOSFET were first evaluated. The results demonstrated the superiority of the SiC MOSFET in both static and switching performances compared to Si devices, but meanwhile did reveal the design tradeoff in terms of the device's gate oxide stability. Various high-temperature packaging materials were then extensively surveyed and carefully selected for the module to sustain the harsh environment. The electrical layout of the module was also optimized using a modeling and simulation approach, in order to minimize the device parasitic ringing during high-speed switching. Finally, the static and switching performances of the fabricated module were tested, and the 200 °C continuous operation of the SiC MOSFETs was verified.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A SiC NMOS Linear Voltage Regulator for High-Temperature Applications
    • Authors: Valle-Mayorga; J.A.;Rahman, A.;Mantooth, H.A.;
      Pages: 2321 - 2328
      Abstract: The first SiC integrated circuit linear voltage regulator is reported. The voltage regulator uses a 20-V supply and generates an output of 15 V, adjustable down to 10 V. It was designed for loads of up to 2 A over a temperature range of 25–225 °C. It was, however, successfully tested up to 300 °C. The voltage regulator demonstrated load regulations of 1.49% and 9% for a 2-A load at temperatures of 25 and 300 °C, respectively. However, the load regulation is less than 2% up to 300 °C for a 1-A load. The line regulation with a 2-A load at 25 and 300 °C was 17 and 296 mV/V, respectively. The regulator was fabricated in a Cree 4H-SiC 2-μm experimental process and consists of 1000, 32/2-μm NMOS depletion MOSFETs as the pass device, an integrated error amplifier with enhancement MOSFETs, and resistor loads, and uses external feedback and compensation networks to ensure operational integrity. It was designed to be integrated with high-voltage vertical power MOSFETs on the same SiC substrate. It also serves as a guide to future attempts for voltage regulation in any type of integrated SiC circuitry.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • High Temperature Stability and the Performance Degradation of SiC MOSFETs
    • Authors: Zhou; W.;Zhong, X.;Sheng, K.;
      Pages: 2329 - 2337
      Abstract: SiC MOSFET devices have great potentials in future high temperature power electronics applications due to their possible higher thermal runaway temperature compared with other SiC power semiconductor devices. In this paper, the high temperature stability of SiC MOSFETs is investigated by experiments and Saber simulations. The maximum steady-state junction temperature of the SiC MOSFET is measured to exceed 250 °C and saber simulations based on experimental model estimate that the thermal runaway temperatures are close to 300 °C. In addition, performance degradation of SiC MOSFETs during high-temperature operation is observed and discussed. Experimental results show that the degradation happens during both the high temperature storage (maximum 5% $R_{rm ON}$ increment) and high temperature operation process (maximum 15% $R_{rm ON}$ increment). The degradations are found to recover to a close-to-initial level after 1 h recovery time at the room temperature.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A 200 °C Safety System at Power-Up of Normally On SiC JFETs
    • Authors: Risaletto; D.;Bergogne, D.;Dubois, F.;Morel, H.;Allard, B.;Meuret, R.;
      Pages: 2338 - 2344
      Abstract: Silicon carbide (SiC) power devices are the only commercialized components to run at high voltage and high temperature. Normally on junction field-effect transistors (JFETs) have lower on-state resistance and lower output capacitance than other SiC switches, which reduces conduction and switching losses. However, normally on power devices induce a short-circuit in voltage-fed inverters (VFI) when the gate driver is not powered prior to the bus supply. This is a power-up limitation that has not received much attention in the literature, especially for safety systems that can be used in an integrated circuit capable of running at elevated temperature. This paper describes an original solution based on SiC JFETs to secure the inverter operation at power-up without gate driver supply for the SiC JFETs. The reliability test of the protection circuit and his impact on the ageing of the JFET of the VFI are also presented. The safety system is capable of running in elevated ambient temperatures. Experimental results have been carried out in a 540 V, 10 A inverter and at ambient temperatures from 27 to 200 °C.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A 120 °C Ambient Temperature Forced Air-Cooled Normally-off SiC
           JFET Automotive Inverter System
    • Authors: Wrzecionko; B.;Bortis, D.;Kolar, J.W.;
      Pages: 2345 - 2358
      Abstract: The degree of integration of power electronic converters in current hybrid electric vehicles can be increased by mitigation of special requirements of these converters, especially those regarding ambient air and cooling fluid temperature levels. Today, converters have their own cooling circuit or are placed far away from hot spots caused by the internal combustion engine and its peripheral components. In this paper, it is shown, how the use of SiC power semiconductors and active control electronics cooling employing a Peltier cooler can help to build an air-cooled inverter system for 120 °C ambient temperature. First, a detailed analysis shows, how the optimum junction of this high-temperature system can be calculated. Then, the operating temperature ranges of power semiconductors, thermal interface materials, capacitors, and control electronics are investigated, leading to a comprehensive analysis of mechanical concepts for the inverter system in order to show new ways to solve electrical and thermal tradeoffs. In particular, the operation of the signal electronics and the gate driver for power semiconductors with a junction temperature of 250 °C within the specified operating temperature range is ensured by appropriate placement and cooling methods, while taking the electrical requirements for limits on the wiring inductances and symmetry requirements into account. The analysis includes an accurate thermal model of the converter and an optimized active cooling of the signal electronics using a Peltier cooler. Finally, a hardware prototype with discrete power semiconductor devices and thus with a junction temperature limit of 175 °C driving high-speed electrical machines is shown to validate the theoretical considerations in a custom-designed high-temperature test environment
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Optimization of the Driver of GaN Power Transistors Through Measurement of
           Their Thermal Behavior
    • Authors: Hoffmann; L.;Gautier, C.;Lefebvre, S.;Costa, F.;
      Pages: 2359 - 2366
      Abstract: GaN field effect power transistors based on Si substrate show low on-state resistance and very small $C_{rm gs}$ capacitance. Therefore these devices are good candidates for high-frequency switching operation. In this paper, we first focus on reverse conduction and transistors behavior during dead times in an inverter leg structure. Then we present an approach by calorimetric method, dedicated to transistors losses evaluation during operation. Using this method, we evaluate in a single measurement the transistors temperature and losses versus a chosen dead time or versus frequency. At least, we conclude on good practices regarding the drive of these components.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Dual-Function Gate Driver for a Power Module With SiC Junction
           Field-Effect Transistors
    • Authors: Colmenares; J.;Peftitsis, D.;Rabkowski, J.;Sadik, D.-P.;Nee, H.-P.;
      Pages: 2367 - 2379
      Abstract: Silicon Carbide high-power modules populated with several parallel-connected junction field-effect transistors must be driven properly. Parasitic elements could act as drawbacks in order to achieve fast and oscillation-free switching performance, which are the main goals. These two requirements are related closely to the design of the gate-drive unit, and they must be kept under certain limits when high efficiencies are targeted. This paper deeply investigates several versions of gate-drive units and proposes a dual-function gate-drive unit which is able to switch the module with an acceptable speed without letting the current suffer from significant oscillations. It is experimentally shown that turn-on and turn-off switching times of approximately 130 and 185 ns respectively can be reached, while the magnitude of the current oscillations is kept at an adequate level. Moreover, using the proposed gate driver an efficiency of approximately 99.7% is expected for a three-phase converter rated at 125 kVA and having a switching frequency of 2 kHz.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Instability in Half-Bridge Circuits Switched With Wide Band-Gap
    • Authors: Lemmon; A.;Mazzola, M.;Gafford, J.;Parker, C.;
      Pages: 2380 - 2392
      Abstract: Wide band-gap (WBG) field-effect devices are known to provide a system-level performance benefit compared to silicon devices when integrated into power electronics applications. However, the near-ideal features of these switching devices can also introduce unexpected behavior in practical systems due to the presence of parasitic elements. The occurrence of self-sustained oscillation is one such behavior that has not received adequate study in the literature. This paper provides an analytical treatment of this phenomenon by casting the switching circuit as an unintentional negative resistance oscillator. This treatment utilizes an established procedure from the oscillator design literature and applies it to the problem of power circuit oscillation. A simulation study is provided to identify the sensitivity of the model to various parameters, and the predictive value of the model is confirmed by experiment involving two exemplary WBG devices: a SiC vertical-channel JFET and a SiC lateral-channel MOSFET. The results of this study suggest that susceptibility to self-sustained oscillation is correlated to the available power density of the device relative to the parasitic elements in the circuit, for which wide band-gap devices, to include SiC and GaN transistors, are in a class approaching that of the radio frequency domain.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • An Experimental Investigation of the Tradeoff between Switching Losses and
           EMI Generation With Hard-Switched All-Si, Si-SiC, and All-SiC Device
    • Authors: Oswald; N.;Anthony, P.;McNeill, N.;Stark, B.H.;
      Pages: 2393 - 2407
      Abstract: Silicon carbide (SiC) switching power devices (MOSFETs, JFETs) of 1200 V rating are now commercially available, and in conjunction with SiC diodes, they offer substantially reduced switching losses relative to silicon (Si) insulated gate bipolar transistors (IGBTs) paired with fast-recovery diodes. Low-voltage industrial variable-speed drives are a key application for 1200 V devices, and there is great interest in the replacement of the Si IGBTs and diodes that presently dominate in this application with SiC-based devices. However, much of the performance benefit of SiC-based devices is due to their increased switching speeds ( di/dt, dv/ dt), which raises the issues of increased electromagnetic interference (EMI) generation and detrimental effects on the reliability of inverter-fed electrical machines. In this paper, the tradeoff between switching losses and the high-frequency spectral amplitude of the device switching waveforms is quantified experimentally for all-Si, Si-SiC, and all-SiC device combinations. While exploiting the full switching-speed capability of SiC-based devices results in significantly increased EMI generation, the all-SiC combination provides a 70% reduction in switching losses relative to all-Si when operated at comparable dv/dt. It is also shown that the loss-EMI tradeoff obtained with the Si-SiC device combination can be significantly improved by driving the IGBT with a modified gate voltage profile.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A Discretized Proportional Base Driver for Silicon Carbide Bipolar
           Junction Transistors
    • Authors: Tolstoy; G.;Peftitsis, D.;Rabkowski, J.;Palmer, P.R.;Nee, H.-P.;
      Pages: 2408 - 2417
      Abstract: Silicon carbide (SiC) bipolar junction transistors (BJTs) require a continuous base current in the on-state. This base current is usually made constant and is corresponding to the maximum collector current and maximum junction temperature that is foreseen in a certain application. In this paper, a discretized proportional base driver is proposed which will reduce, for the right application, the steady-state power consumption of the base driver. The operation of the proposed base driver has been verified experimentally, driving a 1200-V/40-A SiC BJT in a dc–dc boost converter. In order to determine the potential reduction of the power consumption of the base driver, a case with a dc–dc converter in an ideal electric vehicle driving the new European drive cycle has been investigated. It is found that the steady-state power consumption of the base driver can be reduced by approximately 60%. The total reduction of the driver consumption is 3459 J during the drive cycle, which is slightly more than the total on-state losses for the SiC BJTs used in the converter.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • On the Use of Front-End Cascode Rectifiers Based on Normally On SiC JFET
           and Si MOSFET
    • Authors: Vazquez; A.;Rodriguez, A.;Fernandez, M.;Hernando, M.M.;Maset, E.;Sebastian, J.;
      Pages: 2418 - 2427
      Abstract: The new wide band-gap semiconductor devices provide new properties to be explored. Normally on silicon carbide (SiC) JFET power devices have several advantages, in particular low switching losses and the potential capabilities of high temperature and high reverse blocking voltage. Looking for improving the overall efficiency in power converters, new structures based on these power devices might be studied. In this paper, a cascode rectifier based on normally on SiC JFET is presented and analyzed. This rectification structure can be applied as front-end rectifier stage for ac–dc power converters, increasing the overall efficiency of these topologies. A second cascode rectifier based on silicon (Si) MOSFET is also studied, as a low-cost alternative. A simple static forward characterization and a brief dynamic behavior analysis of the proposed cascode rectifier structure are made. Both cascode structures are compared with traditional Si rectifier diodes and front-end rectifiers, using an active power factor corrector (PFC) interleaved boost converter. As a result of this comparison, an efficiency improvement as high as two points is obtained. An additional OR gate based on a diode is also used as second test circuit to compare the proposed structures to the traditional Si rectifiers. A reduction between 75% and 55% of the total loss are obtained in this second experimental test.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Switching Performance Comparison of the SiC JFET and SiC JFET/Si MOSFET
           Cascode Configuration
    • Authors: Rodriguez Alonso; A.;Fernandez Diaz, M.;Lamar, D.G.;Arias Perez de Azpeitia, M.;Hernando, M.M.;Sebastian, J.;
      Pages: 2428 - 2440
      Abstract: Silicon Carbide (SiC) devices are becoming increasingly available in the market due to the mature stage of development fact of their manufacturing process. Their numerous advantages compared to silicon (Si) devices, such as, for example, higher blocking capability, lower conduction voltage drop, and faster transitions make them more suitable for high-power and high-frequency converters. The aim of this paper is to study the switching behavior of the two most-widely studied configurations of SiC devices in the literature: the normally-on SiC JFET and the cascode using a normally-on SiC JFET and a low-voltage Si MOSFET. A detailed comparison of the turn-on and turn-off losses of both configurations is provided and the results are verified against the experimental efficiency results obtained in a boost converter operating in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). Furthermore, special attention will be paid to the switching behavior of the cascode configuration, analyzing the effect of its low-voltage Si MOSFET and comparing different devices. The study carried out will confirm that the overall switching losses of the JFET are lower, making it more suitable for operating in the CCM in terms of the overall converter efficiency. However, the lower turn-off losses of the cascode show this device to be more suitable for the DCM when ZVS is achieved at the turn-on of the main switch. Finally, all the theoretical results have been verified in an experimental 600-W boost converter.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Investigations of 600-V GaN HEMT and GaN Diode for Power Converter
    • Authors: Mitova; R.;Ghosh, R.;Mhaskar, U.;Klikic, D.;Wang, M.-X.;Dentella, A.;
      Pages: 2441 - 2452
      Abstract: Power switching devices based on wide bandgap semiconductor materials, such as silicon carbide (SiC) and gallium nitride (GaN) offer superior performance such as low switching and conduction losses, high voltage, high frequency, and high temperature operation. In this paper, a 600-V GaN switch and a 600-V GaN diode were tested in detail to understand the GaN device capabilities with respect to equivalent silicon-based devices such as IGBT and MOSFET. Detailed experimental loss models are developed and compared with datasheet models. Experimental setup of different power converters such as boost, buck–boost, and half-bridge inverter and associated comparative experimental results are presented. This paper also presents the investigations into the effectiveness of using GaN devices and higher switching frequencies in reducing the total size and cost of power conversion equipment such as an online UPS system.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Evaluation and Application of 600 V GaN HEMT in Cascode Structure
    • Authors: Huang; X.;Liu, Z.;Li, Q.;Lee, F.C.;
      Pages: 2453 - 2461
      Abstract: Gallium nitride high electron mobility transistor (GaN HEMT) has matured dramatically over the last few years. A progressively larger number of GaN devices have been manufactured for in field applications ranging from low power voltage regulators to high power infrastructure base-stations. Compared to the state-of-the-art silicon MOSFET, GaN HEMT has a much better figure of merit and shows potential for high-frequency applications. The first generation of 600 V GaN HEMT is intrinsically normally on device. To easily apply normally on GaN HEMT in circuit design, a low-voltage silicon MOSFET is in series to drive the GaN HEMT, which is well known as cascode structure. This paper studies the characteristics and operation principles of a 600 V cascode GaN HEMT. Evaluations of the cascode GaN HEMT performance based on buck converter at hard-switching and soft-switching conditions are presented in detail. Experimental results prove that the cascode GaN HEMT is superior to the silicon MOSFET, but it still needs soft-switching in high-frequency operation due to considerable package and layout parasitic inductors and capacitors. The cascode GaN HEMT is then applied to a 1 MHz 300 W 400 V/12 V LLC converter. A comparison of experimental results with a state-of-the-art silicon MOSFET is provided to validate the advantages of the GaN HEMT.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • High-Frequency PWM Buck Converters Using GaN-on-SiC HEMTs
    • Authors: Rodriguez; M.;Zhang, Y.;Maksimovic, D.;
      Pages: 2462 - 2473
      Abstract: GaN high electron mobility transistors (HEMTs) are well suited for high-frequency operation due to their lower on resistance and device capacitance compared with traditional silicon devices. When grown on silicon carbide, GaN HEMTs can also achieve very high power density due to the enhanced power handling capabilities of the substrate. As a result, GaN-on-SiC HEMTs are increasingly popular in radio-frequency power amplifiers, and applications as switches in high-frequency power electronics are of high interest. This paper explores the use of GaN-on-SiC HEMTs in conventional pulse-width modulated switched-mode power converters targeting switching frequencies in the tens of megahertz range. Device sizing and efficiency limits of this technology are analyzed, and design principles and guidelines are given to exploit the capabilities of the devices. The results are presented for discrete-device and integrated implementations of a synchronous Buck converter, providing more than 10-W output power supplied from up to 40 V with efficiencies greater than 95% when operated at 10 MHz, and greater than 90% at switching frequencies up to 40 MHz. As a practical application of this technology, the converter is used to accurately track a 3-MHz bandwidth communication envelope signal with 92% efficiency.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Evaluation of SiC BJTs for High-Power DC–DC Converters
    • Authors: Calderon-Lopez; G.;Forsyth, A.J.;Gordon, D.L.;McIntosh, J.R.;
      Pages: 2474 - 2481
      Abstract: The design of a 200-A, all-SiC power-module-based on bipolar junction transistor devices is described, and the impact of the module is assessed on the performance of a 50-kW dc–dc converter for electric vehicle applications, particularly the overall weight and efficiency. Using a hard-switching dual-interleaved topology, which has proven high efficiency and high-power density capability, the operation of a 50-kW, 75-kHz all-SiC converter is compared with that of an insulated-gate bipolar transistor-based silicon converter, switching at 25 kHz, each providing 600-V output. The results show that the total losses are reduced by almost 40%, whilst the overall weight is reduced by 27%, achieving a power density of 10.5 kW/kg. Experimental results of the SiC converter operating at 220–600 V, 52.8 kW are provided, showing an efficiency of 97%.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Parallel-Operation of Discrete SiC BJTs in a 6-kW/250-kHz DC/DC Boost
    • Authors: Rabkowski; J.;Peftitsis, D.;Nee, H.-P.;
      Pages: 2482 - 2491
      Abstract: This paper describes issues related to parallel connection of SiC bipolar junction transistors (BJTs) in discrete packages. The devices are applied in a high-frequency dc/dc boost converter where the switching losses significantly exceed the conduction losses. The design and construction of the converter is discussed with special emphasis on successful parallel-operation of the discrete BJTs. All considerations are experimentally illustrated by a 6-kW, 250-kHz boost converter (300 V/600 V). A special solution for the base-drive unit, based on the dual-source driver concept, is also shown in this paper. The performance of this driver and the current sharing of the BJTs are both presented. The power losses and thermal performance of the parallel-connected transistors have been determined experimentally for different powers and switching frequencies. An efficiency of 98.23% (±0.02%) was measured using a calorimetric setup, while the maximum temperature difference among the four devices is 12 °C.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Design and Evaluation of Reduced Self-Capacitance Inductor in DC/DC
           Converters with Fast-Switching SiC Transistors
    • Authors: Zdanowski; M.;Kostov, K.;Rabkowski, J.;Barlik, R.;Nee, H.-P.;
      Pages: 2492 - 2499
      Abstract: The paper presents an inductor with reduced self-capacitance, designed and evaluated with fast-switching SiC transistors in dc–dc converters. A conventional inductor with the same core and number of turns was also build for comparison. The two inductors are tested experimentally on two different 2 kW, 100 kHz dc–dc converters with silicon carbide switches—one with a junction field-effect transistor (JFET) and the other with a bipolar junction transistor (BJT). Replacing the conventional inductor with the one that has lower self-capacitance improved the switching performance of the converter and reduced its electromagnetic emissions. Furthermore, the efficiency of the converter is improved—in the case of the JFET boost converter the power losses were reduced by 16% and by 20% in the case of BJT.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A Wide Bandgap Device-Based Isolated Quasi-Switched-Capacitor DC/DC
    • Authors: Zhang; X.;Yao, C.;Li, C.;Fu, L.;Guo, F.;Wang, J.;
      Pages: 2500 - 2510
      Abstract: This paper proposes an isolated quasi-switched-capacitor (QSC) dc/dc converter to serve as an auxiliary power supply in electric and hybrid electric vehicles, managing a bidirectional power flow between the high-voltage (HV) battery and the low-voltage dc bus. A QSC dc/ac circuit with a 3:1 voltage step-down ratio is proposed to serve as the front-stage circuit of the converter. Based on it, an isolated QSC dc/dc converter is proposed with a synchronous-rectifier, current-doubler post-stage circuit. Compared with existing full-bridge, half-bridge, and three-level converters, the features of the proposed converter include: 1) the voltage stresses on HV-side switches are reduced to two-third of the HV-dc-bus voltage; 2) the voltage stress on transformer is reduced to one-third of the HV-dc-bus voltage; 3) the transformer turns ratio is reduced; 4) it has soft-switching capability and high efficiency; and 5) bidirectional power-flow and simple control can be implemented. The operation principles, soft-switching analysis, and simulation results are presented. Wide Bandgap devices are selected for the proposed converter to shrink the size of passive components, provide high efficiency, and decrease the cooling requirement. Guidelines are given to estimate the key circuit parameters, including the capacitance of the switched capacitors, the transformer dc-bias flux density, and the average currents of the post-stage inductors. Experiment results provided from a 1-kW prototype built with SiC MOSFETs on the HV-side validate the feasibility and superior performance of the proposed converter.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Classification and Comparative Evaluation of PV Panel-Integrated
           DC–DC Converter Concepts
    • Authors: Kasper; M.;Bortis, D.;Kolar, J.W.;
      Pages: 2511 - 2526
      Abstract: The strings of photovoltaic panels have a significantly reduced power output when mismatch between the panels occurs, as, e.g., caused by partial shading. With mismatch, either the panel-integrated diodes are bypassing the shaded panels if the string is operated at the current level of the unshaded panels, or some power of the unshaded panels is lost if the string current is reduced to the level of the shaded panels. With the implementation of dc–dc converters on panel level, the maximum available power can be extracted from each panel regardless of any mismatch. In this paper, different concepts of PV panel-integrated dc–dc converters are presented and their suitability for panel integration is evaluated. The buck–boost converter is identified as the most promising concept and an efficiency/power density ( $eta$ - $rho$ ) Pareto optimization of this topology is shown. Based on the optimization results, two $275,hbox{W}$ converter prototypes with either Silicon MOSFETs with a switching frequency of $hbox{100 kHz}$ or gallium nitride FETs with a switching frequency of $hbox{400 kHz}$ are designed for an input voltage range of 15 to $hbox{45 V}$ and an output voltage range of 10 to $hbox{100 V}$ . The theoretical considerations are verified by efficiency measurements which are compared to the characteristics of a commercial panel-integrated converter.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • An Experimental Evaluation of SiC Switches in Soft-Switching Converters
    • Authors: Ranstad; P.;Nee, H.-P.;Linner, J.;Peftitsis, D.;
      Pages: 2527 - 2538
      Abstract: Soft-switching converters equipped with insulated gate bipolar transistors (IGBTs) in silicon (Si) have to be dimensioned with respect to additional losses due to the dynamic conduction losses originating from the conductivity modulation lag. Replacing the IGBTs with emerging silicon carbide (SiC) transistors could reduce not only the dynamic conduction losses but also other loss components of the IGBTs. In the present paper, therefore, several types of SiC transistors are compared to a state-of-the-art 1200-V Si IGBT. First, the conduction losses with sinusoidal current at a fixed amplitude (150 A) are investigated at different frequencies up to 200 kHz. It was found that the SiC transistors showed no signs of dynamic conduction losses in the studied frequency range. Second, the SiC transistors were compared to the Si IGBT in a realistic soft-switching converter test system. Using a calorimetric approach, it was found that all SiC transistors showed loss reductions of more than 50%. In some cases loss reductions of 65% were achieved even if the chip area of the SiC transistor was only 11% of that of the Si IGBT. It was concluded that by increasing the chip area to a third of the Si IGBT, the SiC vertical trench junction field-effect transistor could yield a loss reduction of approximately 90%. The reverse conduction capability of the channel of unipolar devices is also identified to be an important property for loss reductions. A majority of the new SiC devices are challenging from a gate/base driver point-of-view. This aspect must also be taken into consideration when making new designs of soft-switching converters using new SiC transistors.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Design and Implementation of a High-Efficiency Multiple-Output Resonant
           Converter for Induction Heating Applications Featuring Wide Bandgap
    • Authors: Sarnago; H.;Lucia, O.;Mediano, A.;Burdio, J.M.;
      Pages: 2539 - 2549
      Abstract: Efficiency is a key design parameter when designing the power converters for domestic induction heating applications, since it determines not only the environmental impact of the power converter but also its final performance and reliability. In this paper, the design of high-efficiency converters for induction heating applications is discussed, focusing on the advantages of using wide bandgap devices. As a conclusion, a multiple-output boost resonant ac–ac converter is proposed, significantly improving current state-of-the-art efficiency and achieving a reduced component-count solution for multiple-load systems. The proposed converter has been tested through a dual-output boost resonant inverter for domestic induction heating applications. The design procedure is detailed, including the design of an optimized gate drive circuit for this application. Experimental results show significant improvements in efficiency in the whole operating range, and an accurate output power control, proving the benefits and feasibility of the proposed SiC-based converter.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A Comparative Performance Study of a 1200 V Si and SiC MOSFET Intrinsic
           Diode on an Induction Heating Inverter
    • Authors: Jordan; J.;Esteve, V.;Sanchis-Kilders, E.;Dede, E.J.;Maset, E.;Ejea, J.B.;Ferreres, A.;
      Pages: 2550 - 2562
      Abstract: This paper presents a comparison of the behavior of the intrinsic diode of silicon (Si) and silicon carbide (SiC) MOSFETs. The study was done for 1200 V Si and SiC MOSFETs. The data sheet from manufacturers shows the characteristics of MOSFET’ intrinsic diode when gate source voltage $(V_{rm GS})$ is 0 V. There are applications where the MOSFET’ intrinsic diode is used while $V_{rm GS}$ is different than 0 V. One of these applications is induction heating, where depending on the load and the regulation system, the diode can conduct a significant part of the inverter current. In most applications which use the MOSFET’ intrinsic diode, the turn ON of the intrinsic diode happens at $V_{rm GS}$ = 0 V. After a blanking time, the MOSFET’ gate is activated waiting for the direction change of current in the circuit. Therefore, most of the current through the MOSFET’ intrinsic diode occurs with a $V_{rm GS}$ different of 0 V. This paper shows the direct output characterization of Si and SiC MOSFET’ intrinsic diode under different gate voltages. The gate resistor $(R_{G})$ is an important parameter of the characterization. Depending on the input capacitance of the Si or SiC MOSFET, different $R_{G}$ are needed. The turn-on and turn-off behaviors are obtained when $R_{G}$ is optimized for each Si and SiC MOSFET. This has result in the turn-off robustness of intrinsic diode with optimum $R_{G}$ . This paper presents a surprising result for the reverse characteristic of Si and SiC MOSFETs for the same current at different $V_{rm GS}$ . The technology of Si MOSFET has different behavior depending on the manufacturer. The technology of SiC MOSFET presents a very similar behavior to low-voltage Si MOSFETs.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Design Challenges in the Use of Silicon Carbide JFETs in Matrix Converter
    • Authors: Empringham; L.;De Lillo, L.;Schulz, M.;
      Pages: 2563 - 2573
      Abstract: This paper investigates some of the challenges encountered during the implementation of a Silicon Carbide JFET matrix converter which has been designed to meet a specific power density of 20 kW/L with forced air cooling. After a brief introduction to the main features of the hardware implementation of the power converter, an insight into the control strategy and controller platform adopted is given with a particular attention to the issues relating to the high switching frequencies on the controller requirements and the performance implications of the gate drive circuitry. An analysis of the results which show the effects of gate driver and controller-induced commutation time limitations on the output waveform quality is presented. Wide bandgap semiconductor devices offer the power electronic engineer new opportunities for high-speed, high-efficiency designs but these devices cannot be used as a simple like for like replacements and as such the whole converter system needs to be looked at in order to successfully exploit these devices.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Realization of a Modular Indirect Matrix Converter System Using Normally
           Off SiC JFETs
    • Authors: Escobar-Mejia; A.;Stewart, C.;Hayes, J.K.;Ang, S.S.;Balda, J.C.;Talakokkula, S.;
      Pages: 2574 - 2583
      Abstract: Silicon carbide (SiC) semiconductors are becoming the preferable choice over silicon (Si) semiconductors for power converter applications within the 200 V to 1.2 kV range due to their superior performances. Indirect matrix converters (IMCs) have more potential than traditional back-to-back power converters (BBCs) for achieving higher power densities and longer equipment lifetimes. This paper combines normally off SiC JFETs and the IMC topology to develop a module-based IMC system whose power stage consists of a bidirectional rectifier power module (BPM) and an inverter power module. This combination achieves a power density of approximately 72 kVA/L at the module level. A 5-kVA IMC prototype operating at a switching frequency of 30 kHz and connected to an RL load demonstrates the functionality of the proposed modular IMC system.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Experimental and Analytical Performance Evaluation of SiC Power Devices in
           the Matrix Converter
    • Authors: Safari; S.;Castellazzi, A.;Wheeler, P.;
      Pages: 2584 - 2596
      Abstract: With the commercial availability of SiC power devices, their acceptance is expected to grow in consideration of the excellent low switching loss, high-temperature operation, and high-voltage rating capabilities of these devices. This paper presents the comparative performance evaluation of different SiC power devices in the matrix converter at various temperatures and switching frequencies. To this end, first, gate or base drive circuits for normally-off SiC JFET, SiC MOSFET, and SiC BJT by taking into account the special demands for these devices are presented. Then, four two-phase to one-phase matrix converters are built with different Si and SiC power devices to measure the switching waveforms and power losses for them at different temperatures and switching frequencies. Based on the measured data, four different SiC and Si power devices are compared in terms of switching times, conduction and switching losses, and efficiency at different temperatures and switching frequencies. Furthermore, a theoretical investigation of the power losses of the three-phase matrix converter with normally-off SiC JFET, SiC MOSFET, SiC BJT, and Si IGBT is described. The power losses estimation indicates that a 7-kW matrix converter would potentially have an efficiency of approximately 94% in high switching frequency if equipped with SiC devices.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • SiC-SIT Circuit Breakers With Controllable Interruption Voltage for 400-V
           DC Distribution Systems
    • Authors: Sato; Y.;Tanaka, Y.;Fukui, A.;Yamasaki, M.;Ohashi, H.;
      Pages: 2597 - 2605
      Abstract: 400-V direct current (400-V dc) distribution systems are promising candidate of highly efficient and reliable distribution systems for data centers. To realize the 400-V dc distribution systems, development of methods for high-speed overcurrent protection is one of the important issues. In this paper, as a solution to this problem, a semiconductor dc circuit breaker using SiC static induction transistors (SiC-SIT’s) is investigated. The SiC-SIT's has extremely low on-state resistance and very large safe operating area (SOA). These properties are attractive in the application of the circuit breakers for 400-V dc distribution systems. A novel control method of the gate voltage waveform to reduce the transient overvoltage and resonance during the interruption process is proposed. The effectiveness of the proposed method is confirmed by actual operation tests employing an experimental prototype of the dc distribution system. All of the result is confirmed by the fabricated SiC-SIT circuit breaker prototype.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A High-Density, High-Efficiency, Isolated On-Board Vehicle Battery Charger
           Utilizing Silicon Carbide Power Devices
    • Authors: Whitaker; B.;Barkley, A.;Cole, Z.;Passmore, B.;Martin, D.;McNutt, T.R.;Lostetter, A.B.;Lee, J.S.;Shiozaki, K.;
      Pages: 2606 - 2617
      Abstract: This paper presents an isolated on-board vehicular battery charger that utilizes silicon carbide (SiC) power devices to achieve high density and high efficiency for application in electric vehicles (EVs) and plug-in hybrid EVs (PHEVs). The proposed level 2 charger has a two-stage architecture where the first stage is a bridgeless boost ac–dc converter and the second stage is a phase-shifted full-bridge isolated dc–dc converter. The operation of both topologies is presented and the specific advantages gained through the use of SiC power devices are discussed. The design of power stage components, the packaging of the multichip power module, and the system-level packaging is presented with a primary focus on system density and a secondary focus on system efficiency. In this work, a hardware prototype is developed and a peak system efficiency of 95% is measured while operating both power stages with a switching frequency of 200 kHz. A maximum output power of 6.1 kW results in a volumetric power density of 5.0 kW/L and a gravimetric power density of 3.8 kW/kg when considering the volume and mass of the system including a case.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • A Space Vector Modulator for the High-Switching Frequency Control of
           Three-Level SiC Inverters
    • Authors: Holtz; J.;Holtgen, M.;Krah, J.O.;
      Pages: 2618 - 2626
      Abstract: Operating three-level inverters at very high switching frequency improves the dynamics of servo drives. It reduces the cost and size of harmonic filters that lessen the $dv/dt$ stress of drive motor windings and bearings. Low harmonic current distortion is a further benefit. Other applications are line-side front end converters, uninterruptable power supplies (UPS), and photovoltaic installations. The requirements of very high-switching frequency control are beyond the computing power of modern microcontrollers and digital signal processors. The problem is overcome by a three-level space vector modulation scheme that defines the switching sequence by taking a sequence of logic decisions instead of doing time-consuming arithmetic operations. The control of the inverter neutral point potential is an inherent part of the scheme and does not need additional algorithms. Implementation in an FPGA permits operating at switching frequencies up to 100 kHz. Experimental results are presented.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Open Access
    • Pages: 2627 - 2627
      Abstract: Advertisement: Purchasing IEEE papers in print is easy, cost-effective and quick.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
  • Publish your article in ieee access
    • Pages: 2628 - 2628
      Abstract: Advertisement: IEEE Access is IEEE's first open-access mega journal that is freely available to the public. Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.
      PubDate: May 2014
      Issue No: Vol. 29, No. 5 (2014)
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