WBG Fractional Power Processing: A New Si-SiC Hybrid Voltage Source Inverter Design

The adoption of wide bandgap (WBG) power semiconductors can improve the performance of power converters at the expense of significantly higher cost than Si at present time. In this paper, a WBG Fractional Power Processing (WFPP) design concept is introduced where silicon devices process the base power at a low switching frequency (2kHz or lower) while WBG devices are judiciously used to process only a fraction of the total power at a much higher frequency (tens of kHz). A 150W Si and SiC hybrid voltage source inverter is investigated as a case study to demonstrate the WFPP concept. A full-power Si inverter and a fractional power SiC inverter operate together to deliver an optimal system performance at a significantly reduced cost than a full-power WBG inverter. Both detailed simulation and experimental results are presented to confirm the benefits of the proposed WFPP concept.