Hybrid-Mode Adaptive Zero-Voltage Switching for Single-Phase DC–AC Conversion With Paralleled SiC MOSFETs

Abstract

State-of-the-art soft-switching modulations such as critical conduction mode and triangular current mode increase the conduction loss of power semiconductors and require variable switching frequencies; thus, these soft-switching methods are seldom used in high-power dc–ac conversion. To achieve soft-switching while maintaining low root mean square currents, this article proposes a hybrid quadrilateral and continuous current mode (HQCCM) modulation for general high-frequency single-phase dc–ac conversion based on paralleled silicon carbide metal oxide semiconductor field-effect transistors. The proposed HQCCM adaptively operates in soft-switching quadrilateral current mode or hard-switching continuous conduction mode in one ac line cycle depending on the instantaneous ac load current. Thus, high efficiencies can be achieved over the full power range. This HQCCM modulation features adaptive soft-switching, constant switching frequency, and compatibility to line filter and is applicable for high-power applications. A 4.4-kW single-phase dc–ac inverter is developed and tested to verify the advantages of the HQCCM. This article is accompanied by a video demonstrating the effectiveness of the proposed HQCCM in varying load scenarios.