Experimental Considerations on Adjustable Dead-Time Control Scheme for Resonant Snubber Inverter

This paper proposes adjustable dead-time control scheme, which avoid the failure of natural zero voltage switching (ZVS) turn-on in low output current in auxiliary resonant snubber inverters (RSIs). RSI achieves ZVS in the inverter main switches using auxiliary circuit; however, additional conduction loss is caused by using the auxiliary circuit simultaneously. The additional conduction loss can be suppressed by decrease of the operating frequency of the auxiliary circuit using natural ZVS, in which ZVS can be achieved without using the auxiliary circuit by using the output current. However, natural ZVS turn-on is failed near zero output current when the dead-time was constant. This paper describes the basic concept of the proposed control scheme and the developed controller using a FPGA (Field Programmable Gate Array). In addition, it was confirmed that the control scheme is effective for the natural ZVS failure problem by PSpice simulations and experiments in single-phase RSI.