Parallel Resonant DC Link Inverter Topology and Analysis of Its Operation Principle

To realize a soft-switching inverter with the advantages of simple structure, high efficiency, low voltage stress, and easy to control, a novel parallel resonant dc link inverter with the function of pulse current regeneration is proposed in this paper. All switches in the inverter main circuit can achieve zero-voltage-switching (ZVS) turn-on and ZVS turn-off. All switches in the auxiliary commutation circuit (ACC) can achieve soft-switching. The power in the ACC is small. Freewheeling diodes in the inverter turn off under the zero-current condition, which can reduce the reverse recovery loss of freewheeling diodes. In addition, the bulk capacitors are avoided in the circuit and there is no neutral point potential variation problem. At the same time, the zero-voltage duration is independent of the load current, and the time of transition can be selected freely. According to the equivalent circuits in different operation modes under the proposed modulation strategy, the operation principle, soft-switching implementation condition, and parameter design procedure of the proposed inverter are analyzed successively in this paper. Finally, a 10-kW-10-kHz soft-switching inverter prototype with insulated gate bipolar transistor (IGBT)-based switches is built. Experimental results are given to demonstrate the validity and features of the soft-switching inverter.