Inductor commutation soft-switched PWM inverter driven by frequency-modulated PWM signal

This paper presents a novel technique using frequency modulation (FM) to improve the efficiency of an inductor commutation soft-switched pulse-width-modulation (PWM) inverter (ICSI). In the ICSI, a circulating current for soft switching always flows through the switches of the inverter, independent of the load and input signal. The circulating current significantly deteriorates the efficiency of ICSI. With the FM technique, the circulating current is effectively suppressed without sensing any current or voltage in the inverter. Efficiencies of ICSI and ICSI with FM (FM ICSI) are analyzed and verified experimentally. As a result, the efficiency of FM ICSI rises about 20%-40% compared with the ICSI.