Evaluation of 1.2 kV SiC MOSFETs in multilevel cascaded H-bridge three-phase inverter for medium-voltage grid applications

Abstract

A study is conducted to evaluate 1.2 kV silicon-carbide (SiC) MOSFETs in a cascaded H-bridge (CHB) three-phase inverter for medium-voltage applications. The main purpose of this topology is to remove the need for a bulky 60 Hz transformer normally used to step up the output signal of a voltage source inverter to a medium-voltage level. Using SiC devices (1.2-6.5 kV SiC MOSFETs) which have a high breakdown voltage, enables the system to meet and withstand the medium-voltage stress using only a minimal number of cascaded modules. The SiC-based power electronics when used in the presented topology considerably reduce the complexity usually encountered when Si devices are used to meet the medium-voltage level and power scalability. Simulation and preliminary experimental results on a low-voltage prototype verifies the nine-level CHB topology presented in this study.

A review of WBG and Si devices hybrid applications

“…By contrast, WBG devices, as represented by SiC and GaN devices, have more advantages in these aspects owing to their material properties. The characteristics of these three materials are compared [41] , as shown in Fig. 2.…”

“…The electron saturation drift speed of the WBG material is about twice that of Si material, and thus power semiconductor devices based on a WBG material can operate at higher switching frequencies [40][41][42][43][44][45] .…”

Monitoring of SiC MOSFET junction temperature with on-state voltage at high currents

“…The on-resistance in the MOSFET consists of eight parts [15] , namely, the drain contact resistance (R CD ), substrate resistance (R S ), drift zone resistance (R D ), JFET zone resistance (R JFET ), cumulative resistance (R A ), channel resistance (R CH ), N+zone resistance (R N+ ) and the source base resistance (R CS ), which are depicted in Fig. 1.…”

“…[ [13][14][15] Body-diode voltage-based Can only be applied to SiC MOSFETs without body diodes, cannot be used for on-line monitoring.…”

Implementation of 1.7 kV silicon carbide metal oxide semiconductor field effect transistors in auxiliary power supplies for industrial applications

“…A single-switch flyback topology is the most common selection, owing to its simple structure, lowest component count, and low cost. However, there are many challenges in using silicon MOSFETs for Aux-PS applications with high input voltages [2][3][4] . There are two main drawbacks to the flyback topology.…”