A Novel Method to Evaluate the Influence of Vienna Rectifier Neutral-Point Voltage Fluctuation on Input Current Quality

The inherent neutral-point (NP) voltage fluctuation of the Vienna rectifier could have side effects on the input current quality. However, such effects have not been thoroughly analyzed in the literature yet. In this article, based on the three-level to two-level space vector modulation transformation, a novel method to evaluate the influence of the NP voltage fluctuation on the input current quality is introduced, which could optimize the NP control parameters. The proposed method superimposes the NP voltage fluctuation on the basis vectors, thereby establishing the correlation between the NP voltage fluctuation and the square root mean square of the input current ripple. The detailed model of the NP oscillation under two-level coordinates is presented. By combining the two-level modulation, NP voltage hysteresis control is adopted to simplify NP voltage control and suppress the NP low-frequency oscillation. The comprehensive influence of the NP compensation coefficient on the input current quality under NP hysteresis control is obtained, and the hysteresis control parameters are optimized by using the proposed evaluation method. The simulation and experimental results verify the correctness and effectiveness of the proposed evaluation method.