A Novel Modulation Method to Decouple Output Power and Suppress Current Zero-Crossing Distortion for Vienna Rectifiers in Bipolar Output Mode

In practical applications, Vienna rectifier often operates in a bipolar output mode to improve efficiency and reduce cost. In this case, the output voltage and power of the upper and lower DC buses are no longer equal, and the vector synthesis becomes very complex. In this paper, the analysis is conducted from the perspective of the carrier, and the zero-sequence voltage (ZSV) is injected to decouple the output power of the upper and lower DC buses and control the neutral point (NP) voltage, which simplified the calculation. Based on the constraints of output level and maximum limit of modulation voltage, the constraints of ZSV are provided. Then, the maximum output power of the upper and lower DC buses relative to the entire DC bus under different operating conditions is calculated, which can provide reference for parameter design. In addition, the current zero-crossing distortion (CZCD) for Vienna rectifier in bipolar output mode is analyzed, and a novel method for suppressing CZCD is proposed and the modulation voltage are directly provided. Finally, an experimental platform is built to verify the feasibility and superiority of the proposed method.