A Three-Phase Five-Level Unidirectional Rectifier With Reduced Components

Owing to the advantages of simple structure, higher power density, and reliability, unidirectional five-level rectifiers are attractive solutions for high-power medium-voltage nonregenerative applications such as electric vehicle charging pile, telecommunication power, and laser power. However, the existing five-level unidirectional rectifiers use more switching devices or flying capacitors (FCs). This will reduce the power density and increase the complexity of the system. To address this issue, this article presents a three-phase five-level unidirectional rectifier with reduced components. It uses only three active switches and one FC per phase. Compared with most similar rectifiers, the number of active switching devices and floating capacitors has been reduced by 25% and 50%, respectively. Consequently, the proposed rectifier has the comprehensive merits in terms of simple structure and higher power density of the system. The operating principles of the proposed topology, control strategy, modulation scheme, and comparison study are presented in depth. Finally, a 3 kW three-phase experimental prototype is built to verify the validity and flexibility of the proposed topology.