A Resonant DC-Link Inverter to Reduce the Influence of Resonant Capacitor of Auxiliary Circuit

The resonant capacitor of the auxiliary circuit (ac) of the resonant dc-link inverter (RDCLI) increases the size of the main circuit, increases the amplitude of the resonant current, and reduces the stability of the system. To address these problems, this article proposes a new RDCLI to reduce the influence of resonant capacitors. First, this inverter does not need to connect resonant capacitors in parallel with the main switches, thus reducing the size of the main circuit. Second, this inverter avoids the series connection of large-capacity capacitors on the dc side as the auxiliary power supply, thus avoiding the influence of large capacitors on the system stability. Finally, this inverter reduces the energy required for the precharge mode by changing the topology of the ac, thus effectively reducing the amplitude of the resonant current, reducing the losses of the ac, and improving the system efficiency. The operation principle of this inverter and the detailed design procedure are given in this article. Finally, the feasibility and stability of this RDCLI are experimentally verified.