A novel load adaptive zero voltage switching utilizing diode reverse recovery current for soft-switching choppers and inverters

Diode reverse recovery normally increases switching losses and produces noises in power electronics circuits. Over the past few decades, device manufacturers put a lot of effort to improve the reverse recovery speed and softness by sacrificing the conduction losses. This paper, however, introduces a novel zero voltage transition concept that utilizes diode reverse recovery current as resonant inductor boosting current to achieve true zero voltage,operation for both resonant snubber based choppers and inverters. Because the amplitude of the diode reverse recovery current is not much dependent on the load current, a near constant boost in resonant inductor current can be implemented with a fixed timing control. The boosting current level can be controlled by selection of diode and resonant inductance. The resonant snubber based chopper and inverter circuits can thus achieve load current adaptively without load current feedback. Simulation results have verified the effectiveness of the proposed method. Experimental results of a two-quadrant full bridge chopper also indicate that the proposed method can achieve zero-voltage switching for the main device at all load current conditions. The proposed design method can also be implemented for other types of zero-voltage transition schemes such as auxiliary resonant commutated pole (ARCP), resonant snubber inverter (RSI), and coupled inductor schemes