Influence of SiC MOSFET Device Parameters on Zero-Voltage Switching Losses

Abstract:
Soft-switching in power converters offers a highly attractive solution to enhance system efficiency by reducing switching losses while also mitigating electromagnetic interference. Although zero-voltage switching (ZVS) significantly reduces switching losses, it does not eliminate them. Considerable turn-OFF losses remain, dependent on transistor parameters such as internal gate resistance, threshold voltage, and parasitic device capacitances. To analyze the influence of these parameters, 1200V SiC MOSFETs from different manufacturers and latest-generation technologies are examined. The residual ZVS losses are measured using a calorimetric method within a half-bridge circuit operated under ZVS up to 350 kHz at an 800V dc-link. This article assists designers in selecting the most suitable power semiconductor devices for soft-switched converters operating at frequencies of up to several hundred kilohertz.