The temperature evolution during a short-circuit (SC) fault in the dies of three different silicon carbide (SiC) 1200-V power devices is presented in this article. Transient electrothermal simulations are performed based on the reconstructed structure of commercially available devices. The simulations reveal the location of the hottest point in each device. The nonisothermal electrical analysis supports the necessity to turn-off SC events rapidly to protect the immunity of the device after a fault. The analysis also reveal differences in delay required to turn-off devices depending on their type. A thorough analysis of the temperature rise in the die of the SiC metal-oxide semiconductor field-effect transistors (MOSFET) device is also presented, where the maximum temperature with regards to different fault cases and circuit characteristics is presented. The impact of the gate resistance, circuit inductance, detection time, drain-source voltage, and gate-source voltage are considered.

In this paper, a new low-loss turn-ON concept for the silicon insulated-gate bipolar transistor (Si-IGBT) in combination with silicon p-i-n diode is presented. The concept is tailored for two-level motor converters in the 100 kW to 1 MW range under the constraint that the output voltages slopes are limited in order to protect the motor windings. Moreover, analyses of the IGBT turn-ON and diode reverse recovery voltage slopes are presented concluding that the diode reverse recovery is the worst case. The concept includes a low-cost measurement of the free-wheeling diode current and temperature by the gate driver without necessity of acquiring this information from the converter control board. By using this concept, the output dv/dt at the diode turn-OFF can be kept approximately constant regardless of the commutated current and junction temperature. Hence, the switching losses could be decreased for the currents and temperatures where the voltage slopes are lower when using a conventional gate driver optimized for the worst case. Moreover, results are shown for one such power semiconductor, showing a total switching loss reduction of up to 28% in comparison with a gate driver without current and temperature measurement. Finally, this concept is particularly suitable for high power semiconductor modules in half-bridge configuration which are recently proposed by several suppliers.

This work investigates the potential for high power density, high efficiency power conversion at extreme cold temperatures, for hybrid electric aircraft applications. A 1 kW GaN-based 3-level power converter was designed and successfully tested from room temperature down to -140 °C, using a custom milled cold-plate. Along with the first demonstration of a flying capacitor multi-level converter and associated components at such low temperature, this work characterized the effect on power conversion losses of various components as a function of temperature. A key finding is that careful attention must be paid to the passive component losses which can increase as the temperature is reduced.

This work investigates the potential for high power density, high efficiency power conversion at extreme cold temperatures, for hybrid electric aircraft applications. A 1 kW GaN-based 3-level power converter was designed and successfully tested from room temperature down to -140 degrees C, using a custom milled cold-plate. Along with the first demonstration of a flying capacitor multi-level converter and associated components at such low temperature, this work characterized the effect on power conversion losses of various components as a function of temperature. A key finding is that careful attention must be paid to the passive component losses which can increase as the temperature is reduced.

Silicon Carbide (SiC) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) have the potential to increase the power density in power electronics converters compared to the currently used silicon (Si). Their benefits are higher efficiency, higher switching speeds, and higher operating temperatures. Moreover, SiC MOSFETs, which are normally-off, offer the possibility to directly replace Si Isolated-Gate-BipolarTransistors (IGBTs) in already existing converter designs with minimal circuit changes. Nevertheless, as an emerging technology, the reliability performance remains to be investigated. A reliability analysis has been performed based on a full-bridge resonant converter rated at 60 kW for modern Electrostatic Precipitator (ESP) power supplies. This analysis shows that introducing SiC devices will increase the lifetime of the converter while reducing the losses. The investment costs of replacing the Si IGBTs with SiC MOSFETs can thus be covered with the reduction of the losses over the economical operational lifetime. Furthermore, a theoretical analysis on how introducing SiC MOSFETs could increase the power density of the converter while maintaining the efficiency and the reliability. Finally, an analysis on introducing redundancy as a way to improve the reliability of the system has been performed.

Commercially available Silicon Carbide (SiC) MOSFET power modules often have a design based on existing packages previously used for silicon insulated-gate bipolar transistors. However, these packages are not optimized to take advantage of the SiC benefits, such as, high switching speeds and high-temperature operation. The package of a half-bridge SiC MOSFET module has been modeled and the parasitic elements have been extracted. The model is validated through experiments. An analysis of the impact of these parasitic elements on the gate-source voltage on the chip has been performed for both low switching speeds and high switching speeds. These results reveal potential reliability issues for the gate-oxide if higher switching speeds are targeted.

Commercially available silicon carbide (SiC) MOSFET power modules often have a design based on existing packages previously used for silicon insulated-gate bipolar transistors. However, these packages are not optimized to take advantage of the SiC benefits, such as high switching speeds and high-temperature operation. The package of a half-bridge SiC MOSFET module has been modeled and the parasitic elements have been extracted. The model is validated through experiments. An analysis of the impact of these parasitic elements on the gate-source voltage on the chip has been performed for both low switching speeds and high switching speeds. These results reveal potential reliability issues for the gate oxide if higher switching speeds are targeted.

The temperature evolution during a short-circuit in the die of three different Silicon Carbide1200-V power devices is presented. A transient thermal simulation was performed based on the reconstructedstructure of commercially available devices. The location of the hottest point in the device iscompared. Finally, the analysis supports the necessity to turn off short-circuit events rapidly in orderto protect the device after a fault.

High power density converters in combination with cryogenic power systems could have a significant impact on the electrification of transportation systems as well as other energy conversion systems. In this study, the cryogenic temperature performance of an EPC gallium-nitride (GaN) power field-effect transistor was evaluated. At - 195 degrees C, an 85 % reduction in on-state resistance, and a 16 % increase in threshold voltage were experimentally measured. Moreover, using a double-pulse test, no major changes in switching characteristics were observed. GaN transistors are thus excellent choices for operation at cryogenic temperatures.

Silicon carbide is an excellent candidate when high temperature power electronics applications are considered. Integrated circuits as well as several power devices have been tested at high temperature. However, little attention has been paid to high temperature passive components that could enable the full SiC potential. In this work, the high-temperature performances of different passive components have been studied. Integrated capacitors in bipolar SiC technology have been tested up to 300 degrees C and, three different designs of inductors have been tested up to 700 degrees C.