Modulation Method for Vienna Rectifier in Dual Load Mode

In engineering applications, Vienna rectifiers are often in a dual load mode to charge series battery packs to improve efficiency and reduce costs. In these situations, the output voltage and power on the upper and lower DC sides will be no longer equal, and the composition of vectors will become very complex. In this paper, the analysis is conducted from the perspective of the carrier, and the zero sequence voltage is injected to decouple the output power on the upper and lower DC sides and actively control the neutral point voltage, which simplifies the calculation process. The constraints of zero sequence voltage are analyzed based on the output level constraints and modulation constraints of the Vienna rectifier topology. Based on the above constraints, the extreme output power on the upper and lower DC sides of the Vienna rectifier in different operation states is given, which can provide a reference for parameter design in engineering. In addition, the problem of current zero-crossing distortion in the Vienna rectifier under the dual load operation condition is analyzed, and a method for suppressing current zero-crossing distortion is proposed. The three-phase modulation voltages are directly provided. The correctness of the theoretical analysis and the superiority of the proposed method are verified by experimental results. © 2023 Automation of Electric Power Systems Press. All rights reserved.