Analysis, design, and implementation of a new ZCZVT commutation cell for PWM DC-AC converters

This paper proposes a new auxiliary commutation cell for PWM inverters that allows the main switches to be turned on and off at zero voltage and zero current with controlled di/dt and dv/dt. The reverse recovery losses of the main diodes are minimized and the auxiliary switches are turned on and off at ZCS. The main switches turn-on at zero current can reduce significantly the undesired effects of the parasitic inductances related to the circuit layout. The commutation losses are practically reduced to zero and the EMI emission can be reduced. The operation of the ZCZVT PWM full-bridge DC-AC converter is analyzed and a design guideline for the auxiliary commutation cell is recommended based on the analysis. Experimental results are presented to demonstrate the feasibility of the proposed commutation cell.