A Novel Three‐Phase Passive Auxiliary Resonant Pole Soft‐Switching Inverter With Symmetrical Auxiliary Networks and Electric Energy Feedback Function

ABSTRACT To solve the problems of high cost, large additional component size, large circulating loss, and complex control in existing auxiliary resonant soft‐switching inverters, a three‐phase passive auxiliary resonant pole inverter (ARPI) with symmetrical auxiliary networks and electric energy feedback function is proposed. On each phase bridge arm of the inverter, a set of passive auxiliary networks (PANs) without large electrolytic capacitors, transformers, and other devices is provided, which is capable of enhancing the power density of the inverter. Additionally, as the auxiliary commutation circuit does not employ auxiliary switches, it not only lowers the hardware cost but also simplifies the control complexity and enhances the reliability of the soft‐switching inverter operation. The proposed topology is capable of enhancing the utilization ratio of DC voltage and reducing the harmonic content of the output waveform. According to the equivalent circuit diagrams in different operating modes, the soft‐switching operating principle and realization conditions of soft‐switching for the proposed ARPI are analyzed. The parameters of passive components are designed with the aim of minimizing the PAN loss. A 3‐kW experimental prototype is constructed. The experimental results indicate that the switching tubes can realize the soft‐switching action and suppress the rate of change of voltage and current. The efficiency of the prototype can reach 98.30% at the rated output power, which is a remarkable improvement compared with the same type of ARPIs.