A Self-Balancing Topology of Vienna Rectifier Based on PD Modulation

Vienna rectifier is widely used in high-voltage and high-power applications that do not require bidirectional power flow. As a three-level converter, the neutral point potential of Vienna rectifier inevitably needs to be controlled. In this paper, a neutral point potential self-balancing topology of Vienna rectifier is proposed. By connecting a small resonant capacitor in series with the neutral point of the filter capacitors, a series resonance at a specific frequency is formed. Combining the switching of traditional control strategies, the switches act to inject the DC zero-sequence component into the neutral point of the DC side capacitors. The existence of the DC zero-sequence component will cause the neutral point potential offset to tend to zero, so that the DC side capacitor voltages can be quickly evenly divided, and the neutral point potential can be self-balanced. The effectiveness of the proposed self-balancing Vienna rectifier topology is verified by simulation.