Single‐phase current‐fed switched‐capacitor five‐level inverter

Abstract

SummaryWith an input‐side boost inductor, current source inverter (CSI) naturally has the unique performance of voltage boosting and continuous input current, but its switching devices need to have reverse blocking capability. Switched‐capacitor (SC) multilevel inverter (MLI) features self‐balancing capacitor voltages and flexible structure, but it suffers the problems of inrush charging current of capacitors and pulse input current. By combining the CSI's input characteristics and the SC‐MLI's output features, this work presents a new five‐level inverter. Its input current is continuous, and there is no inrush current. In addition, the voltage gain is improved to 2/(1−d), where d is the duty ratio of the inductor's charging mode. With the unique structure, the duty ratio ranges from 0 to 1, and it is independent of the modulation ratio of the inverter. This makes the control more flexible. In addition to topology, operation, and modulation, parameter design, power loss, and comparison study are analyzed in detail. Finally, simulation results with fuel cell as input, and experimental results are provided to verify the superior performance of the proposed inverter.