Neutral-Point Voltage Balance Control and Oscillation Suppression for VIENNA Rectifier

In view of a three-phase/ level boost rectifier, the performance of VIENNA rectifier is affected by the neutral-point (NP) voltage unbalance and oscillation. A novel strategy of zero-sequence component injection to balance the neutral-point voltage and suppress oscillation for VIENNA rectifier is proposed in this paper. Based on the mathematical expressions of neutral-point voltage, a simplified carrier-based PWM based on the equivalence of SVM is implemented to balance the neutral-point voltage. Analyzing mathematical relationship between the fluctuation of neutral-point voltage and the zero-sequence component, an optimized zero-sequence component is proposed to suppress neutral-point voltage oscillation. The validity of the theoretical analysis and feasibility of the proposed strategy are verified by simulation and experimental results.