Wide bandgap (WBG) device-based power electronics converters are more efficient and lightweight than silicon-based converters. WBG devices are an enabling technology for many motor drive applications and new classes of compact and efficient motors. This paper reviews the potential applications and advances enabled by WBG devices in ac motor drives. Industrial motor drive products using WBG devices are reviewed, and the benefits are highlighted. This paper also discusses the technical challenges, converter design considerations, and design tradeoffs in realizing the full potential of WBG devices in motor drives. There is a tradeoff between high switching frequency and other issues such as high dv/dt and electromagnetic interference. The problems of high common mode currents and bearing and insulation damage, which are caused by high dv/dt , and the reliability of WBG devices are discussed.

Wide Bandgap Devices in AC Electric Drives: Opportunities and Challenges

This paper reviews the current state of the art of condition monitoring and fault diagnosis techniques for permanent magnet (PM) machines. It also takes into account the past research on this subject as appropriate. The discussion in this paper includes issues related to common abnormalities and specific faults in PM machines and drives, such as magnet damage and demagnetization, rotor eccentricity, unbalanced magnetic pull, open- and short-circuit windings, and switch faults. In this paper, a detailed review is present on the sources of these faults, their analytical model and fault detection tools. Finally, an integrated methodology for condition monitoring of PM machines is discussed.

Fault Diagnosis Techniques for Permanent Magnet AC Machine and Drives—A Review of Current State of the Art

SiC MOSFETs (silicon carbide metal-oxide semiconductor field-effect transistors) are replacing Si insulated gate bipolar transistors in many power conversion applications due to their superior performance. However, ruggedness and reliability of SiC MOSFETs are still big concern for their widespread applications in the market, especially in safety-critical applications. The objective of this study is to provide a comprehensive picture on the ruggedness and reliability of commercial SiC MOSFETs, discover their failure or degradation mechanism, and propose some possible mitigation methods through both literature survey and in-depth analysis. The ruggedness of SiC MOSFETs discussed here includes short-circuit (SC) ruggedness, avalanche ruggedness, and their failure mechanism. The reliability issues include gate oxide reliability, degradation under high-temperature bias stress, repetitive SC stress, avalanche stress, power cycling stress, body diode's surge current stress, and their degradation mechanism. Furthermore, this study discusses methods and solutions to improve their ruggedness and reliability.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-pel.2019.0587

Review and analysis of SiC MOSFETs’ ruggedness and reliability

In this article, a condition monitoring system for the degradation assessment of power semiconductor modules under switching conditions is presented. The proposed monitoring system is based on the online measurement of two damage indicators: the on -state voltage of the semiconductor and the voltage drop in the bond wires. The on-state voltage of a semiconductor can be employed for temperature estimation, in order to anticipate failures in the solder joints that increase the thermal resistance of the cooling path. Moreover, by measuring the voltage drop in the bond wires, the degradation of the bond wires can be detected. The described monitoring system has been implemented in an inverter prototype, and tests have been performed in different scenarios to verify its capabilities in healthy and degraded states. Furthermore, a monitoring routine has been proposed in order to perform the required measurements in high switching frequency applications.

/pdf/wear-out-condition-monitoring-of-igbt-and-mosfet-power-4uen534z48.pdf

Wear-Out Condition Monitoring of IGBT and mosfet Power Modules in Inverter Operation

In this article, the static, dynamic, and short-circuit properties of 1.2-kV commercial 4H-SiC planar and trench gate metal–oxide–semiconductor field-effect transistors (MOSFETs) are compared and analyzed in a wide temperature range from 90 to 493 K. The temperature-dependent specific ON-resistance ( ${R}_{\text {sp}- \mathrm{\scriptscriptstyle ON}}$ ) and threshold voltage ( ${V}_{\text {th}}$ ) are analyzed in relation to the density of the interface state. The turn-on rise and turn-off fall times ( ${T}_{r}$ and ${T}_{f}$ ) and the corresponding energy loss ( ${E}_{r}$ and ${E}_{f}$ ) are extracted from a double-pulse test from cryogenic to high temperature and analyzed. The short-circuit capability of the two structures is studied at low temperature for the first time. The comprehensive comparison and analysis of the planar and trench gate MOSFET versus temperature in this work show the importance to study applications with SiC MOSFETs in a wide temperature range, especially for the cryogenic temperatures.

Comprehensive Characterization of the 4H-SiC Planar and Trench Gate MOSFETs From Cryogenic to High Temperature

SiC power devices offer performance advantages over competing Si-based power devices, due to the wide bandgap and other key materials properties of 4H-SiC. For example, SiC can more easily be used to fabricate MOSFETs with very high voltage ratings (up to 10 kV), and with lower switching losses. The reliability of SiC power devices is excellent and has continued to improve due to continuing advancements in SiC substrate quality, epitaxial growth capabilities, and device processing. This has enabled the continually accelerating growth of SiC power device commercial adoption. This paper reviews the wear-out mechanisms and intrinsic reliability performance of power SiC devices as characterized by time-dependent dielectric breakdown (TDDB), accelerated life test high temperature reverse bias (ALT-HTRB), terrestrial neutron exposure, and power cycling. This paper also reviews some of the known failure mechanisms that have been characterized and addressed through technological advances. Finally, we present field return data that demonstrates less than 5 FIT (fails per billion device hours) for commercially produced SiC MOSFETs and Schottky diodes, with over 2 trillion device field hours.

Habib Mustain

Papers

SiC power device reliability