The analyses of ZVS turn-off loss and the new snubber circuit for the ARCP inverter

This paper indicates two problems with the auxiliary resonant commutated pole (ARCP) inverter and proposes solutions of these problems. One of the problems is the increase of the turn-off losses of the main switches due to a lead inductance. Each of the resonant capacitors are connected closely with the main switches in the ARCP inverter. However, as the wire that connects DC capacitors with the main switches acts as a reactive component, called the “lead inductance”, this causes imbalance between the currents flowing through the capacitors. Consequently, the turn-off losses of the main switches increase. The other problem is the surge voltage induced in the diodes of the auxiliary commutation circuit. As these diodes are connected in series with the resonant inductor, high surge voltages are induced even though their recovery currents are small. This paper proposes analyses of these turn-off loss considering the effect of the lead inductance as well as a new snubber circuit for suppressing the surge voltages across the diodes in the auxiliary commutation circuit. The turn-off losses evaluated by the analytical equations agree well with experimental results, and the effects of the new snubber circuit are confirmed by these experiments