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.

A Survey of Wide Bandgap Power Semiconductor Devices

Wireless power transfer (WPT) using magnetic resonance is the technology which could set human free from the annoying wires. In fact, the WPT adopts the same basic theory which has already been developed for at least 30 years with the term inductive power transfer. WPT technology is developing rapidly in recent years. At kilowatts power level, the transfer distance increases from several millimeters to several hundred millimeters with a grid to load efficiency above 90%. The advances make the WPT very attractive to the electric vehicle (EV) charging applications in both stationary and dynamic charging scenarios. This paper reviewed the technologies in the WPT area applicable to EV wireless charging. By introducing WPT in EVs, the obstacles of charging time, range, and cost can be easily mitigated. Battery technology is no longer relevant in the mass market penetration of EVs. It is hoped that researchers could be encouraged by the state-of-the-art achievements, and push forward the further development of WPT as well as the expansion of EV.

Wireless Power Transfer for Electric Vehicle Applications

DC-link capacitors are an important part in the majority of power electronic converters which contribute to cost, size and failure rate on a considerable scale. From capacitor users' viewpoint, this paper presents a review on the improvement of reliability of dc link in power electronic converters from two aspects: 1) reliability-oriented dc-link design solutions; 2) conditioning monitoring of dc-link capacitors during operation. Failure mechanisms, failure modes and lifetime models of capacitors suitable for the applications are also discussed as a basis to understand the physics-of-failure. This review serves to provide a clear picture of the state-of-the-art research in this area and to identify the corresponding challenges and future research directions for capacitors and their dc-link applications.

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Reliability of Capacitors for DC-Link Applications in Power Electronic Converters—An Overview

Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper.

https://ieeexplore.ieee.org/ielaam/41/8031005/7815312-aam.pdf

Review of Silicon Carbide Power Devices and Their Applications

Gallium nitride (GaN) power devices are an emerging technology that have only recently become available commercially. This new technology enables the design of converters at higher frequencies and efficiencies than those achievable with conventional Si devices. This paper reviews the characteristics and commercial status of both vertical and lateral GaN power devices, providing the background necessary to understand the significance of these recent developments. In addition, the challenges encountered in GaN-based converter design are considered, such as the consequences of faster switching on gate driver design and board layout. Other issues include the unique reverse conduction behavior, dynamic $R_{\mathrm {{ds}},\mathrm {{on}}}$ , breakdown mechanisms, thermal design, device availability, and reliability qualification. This review will help prepare the reader to effectively design GaN-based converters, as these devices become increasingly available on a commercial scale.

Review of Commercial GaN Power Devices and GaN-Based Converter Design Challenges

Along with the rapid growth in electric vehicle (EV) market, higher power density and more efficient motor drive inverters are required. It is well known that silicon carbide (SiC) has advantages of high temperature, high efficiency and high switching frequency. It is believed that the appropriate utilization of these merits can pave the way to ultra-high power density inverters. This paper presents issues about SiC chip’s current-carrying capability enhancement which is crucial for a compact inverter of tens and hundreds of kilowatts. Technical approaches towards ultra-high power density EV inverter including SiC module packaging, dc-link capacitor function analysis and system level integration are discussed. Different PWM algorithms which may improve efficiency and help to reduce the inverter volume are also studied.

/pdf/technical-approaches-towards-ultra-high-power-density-sic-1w856n6cm8.pdf

Technical approaches towards ultra-high power density SiC inverter in electric vehicle applications

Over the past ten years, there has been increased incorporation of electronic power processing into alternative, sustainable, and distributed energy sources, as well as energy storage systems, cars, airplanes, ships, homes, data centers, and the power grid. The goals have been to reduce the size, weight, and maintenance and operational costs of these power systems, while increasing overall energy efficiency, safety, and reliability. This paper summarizes some of the authors' research efforts in the last four years on the improvements in power density and physical integration of power converters, mostly for vehicular applications. Several approaches to integration of active components into high-temperature modules are presented together with examples of the evaluation and modeling of 1.2 kV SiC JFET and MOSFET. Possible improvements in the power density through hybrid passive and active integration of an EMI filter and of an energy storage capacitor in single-phase PWM rectifier are also shown. Examples of converter integration for a 10 kW motor drive with active front-end using SiC devices operating at 250 °C, and for paralleling three-phase boost rectifiers with interleaved PWM are presented.

High-density system integration for medium power applications

Silicon carbide (SiC) devices have its unique advantages of high operating temperature, high voltage capability with low switching losses when compared to its silicon counterparts. This paper presents a systematic method for long-term reliability analysis for SiC devices. The reliability block diagrams (RBDs) have been established for a SiC power module with standard wire-bonded package. The reliability function and mean time to failure (MTTF) for this module has been estimated by using the lifetime models for single bond wire and SiC chip. The analysis shows that the bond wires are the weakest line of the whole device's reliability. Therefore, it is obvious that utilizing to the full potential of SiC devices is critical for increasing the reliability of package. Design for novel package structure (e.g. without bond wires) may be a possible solution.

Reliability modeling and analysis of SiC MOSFET power modules

To take full advantage of silicon carbide semiconductor devices, high-temperature device packaging needs to be developed. This paper describes potential defects from design and fabrication procedures, and presents a systematic electrical evaluation process to detect such defects. This systematic testing procedure can rapidly detect many defects and reduce the risk in high-temperature packaging testing. A multichip module development procedure that uses this testing procedure is also presented and demonstrated with an example.

High Temperature SiC Power Module Electrical Evaluation Procedure

A novel packaging structure for medium power modules featuring power semiconductor switches sandwiched between two symmetric substrates that fulfill electrical conduction and insulation functions is presented. Large bonding areas between dies and substrates allow this packaging technology to offer significant improvements in electrical, thermal performance. Double-sided cooling system was dedicatedly analyzed and designed for different applications.

Puqi Ning

Papers

Technical approaches towards ultra-high power density SiC inverter in electric vehicle applications

High-density system integration for medium power applications

Reliability modeling and analysis of SiC MOSFET power modules

High Temperature SiC Power Module Electrical Evaluation Procedure

Double-sided cooling design for novel planar module