The behavior of silicon carbide (SiC) power MOSFETs under stressful short-circuit (SC) conditions is investigated in this paper. Two different SC failure phenomena for SiC power MOSFETs are thoroughly reported. Experimental evidence and TCAD electrothermal simulations are exploited to describe and discriminate the failure sources. Physical causes are finally investigated and explained by means of properly calibrated numerical investigations and are reported along with their effects on devices' SC capability.

In this paper, benchmark of Si IGBT, SiC MOSFET, and Gallium nitride (GaN) HEMT power switches at 600-V class is conducted in single-phase T-type inverter. Gate driver requirements, switching performance, inverter efficiency performance, heat sink volume, output filter volume, and dead-time effect for each technology is evaluated. Gate driver study shows that GaN has the lowest gate driver losses above 100 kHz and below 100 kHz, SiC has lowest gate losses. GaN has the best switching performance among three technologies that allows high efficiency at high-frequency applications. GaN-based inverter operated at 160-kHz switching frequency with 97.3% efficiency at 2.5-kW output power. Performance of three device technologies at different temperature, switching frequency, and load conditions shows that heat sink volume of the converter can be reduced by 2.5 times by switching from Si to GaN solution at 60 °C case temperature, and for SiC and GaN, heat sink volume can be reduced by 2.36 and 4.92 times, respectively, by increasing heat sink temperature to 100 °C. Output filter volume can be reduced by 43% with 24, 26, and 61 W increase in device power loss for GaN-, SiC-, and Si-based converters, respectively. WBG devices allow reduction of harmonic distortion at output current from 3.5% to 1.5% at 100 kHz.

Photovoltaic (PV) energy conversion has been on the spotlight of scientific research on renewable energy for several years. In recent years, the bulk of the research on PV has focused on transformerless grid-connected inverters, more efficient than traditional line transformer-based ones, but more critical from a power quality point of view, especially in terms of ground leakage current. Neutral-point-clamped (NPC) inverters have recently gained interest due to their intrinsically low ground leakage current and high efficiency, especially for MOSFET-based topologies. This paper presents an active NPC (ANPC) topology equipped with 650-V silicon carbide (SiC) MOSFETs, with a new modulation strategy that allows to reap the benefits of the wide-bandgap devices. An efficiency improvement is obtained due to the parallel operation of two devices during the freewheeling intervals. Simulations and experimental results confirm the effectiveness of the proposed converter.

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.

This paper is concerned with the thermal models which can physically reflect the heat-flow paths in a lightweight three-phase half-bridge two-level SiC power module with six MOSFETs and can be used for coupled electrothermal simulation. The finite-element (FE) model was first evaluated and calibrated to provide the raw data for establishing the physical resistor-capacitor (RC) network model. It was experimentally verified that the cooling condition of the module mounted on a water cooler can be satisfactorily described by assuming the water cooler as a heat exchange boundary in the FE model. The compact RC network consisting of 115 R and C parameters to predict the transient junction temperatures of the six MOSFETS was constructed, where cross-heating effects between the MOSFETs are represented with lateral thermal resistors. A three-step curve fitting method was especially developed to overcome the challenge for extracting the R and C values of the RC network from the selected FE simulation results. The established compact RC network model can physically be correlated with the structure and heat-flow paths in the power module, and was evaluated using the FE simulation results from the power module under realistic switching conditions. It was also integrated into the LTspice model to perform the coupled electrothermal simulation to predict the power losses and junction temperatures of the six MOSFETs under switching frequencies from 5 to 100 kHz which demonstrate the good electrothermal performance of the designed power module.