Novel Auxiliary Resonant Pole Inverter and its Optimal Control Strategy

Abstract

Conventional inverters operate in hard‐switching mode, and as the switching frequency increases, the switching losses increase dramatically. Increasing the switching frequency helps reduce the size and cost of the inverter, but too high a switching frequency generates greater switching losses, which affects the inverter's transmission efficiency. In response to the problem that conventional hard‐switching inverters cannot be higher in frequency and have high switching losses and low transmission efficiency, an optimized auxiliary resonant commutated inverter and control strategy are proposed to make the inverter work in soft‐switching mode, which helps reduce the switching losses. The auxiliary converters in the bridge arm topology of each phase of the three‐phase inverter are divided into two groups, and the operating auxiliary converters are selected according to the direction of the load current. When the load current direction is positive, the upper bridge arm auxiliary device works and the lower bridge arm auxiliary device turns off, similarly when the load current direction is negative, the lower bridge arm auxiliary device works and the upper bridge arm auxiliary device turns off, this can ensure that only one group of devices works every half cycle, making the control strategy simple and reducing auxiliary circuit losses. Simulation and experimental verification of the effectiveness of the proposed scheme. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.