Efficiency Optimization for Single-Phase Voltage-Sourced Inverter with ZVS-CV

Metal-oxide-semiconductor field-effect transistor (MOSFET) can be utilized to raise switching frequency (SF) while zero voltage switching-clamped voltage (ZVS-CV) is a simple technique to eliminate switching loss without extra resonant circuit. Then, heat sink and filter can both be so shrunk that compact inverter can fit the single-phase system in residential site while high efficiency fulfills regulation(s). In order to ensure the ZVS-CV operation, the inverter's filter inductor must flow such high ripple current that can charge or discharge parasitic capacitances of a MOSFET totem pole, however trades off conduction loss of MOSFET. This study proposes a simple scheme for adapting the SF ripple current to the profile of line frequency (LF) sinusoid meanwhile ZVS-CV operation is maintained, thus efficiency is optimized. Simulations are conducted with 220 V 60 Hz LF single phase full-bridge buck inverter to verify the efficiency enhancement on a load about 1 kW.