Neutral-Point Voltage Control Strategy of Vienna Rectifiers Based on Hybrid DPWM

Vienna rectifier is a boost type rectifier with a unidirectional energy flow, widely used in industry. To further enhance its performance, the hybrid discontinuous pulse width modulation (HDPWM) technique is commonly employed to reduce switching losses and neutral-point voltage fluctuations. This article proposes a control strategy that can adjust the neutral-point voltage balance based on the existing DPWM1 and DPWM3 hybrid DPWM. The proposed strategy maintains the advantages of low switching loss, minimal neutral-point voltage fluctuation, and zero crossing clamping of HDPWM. A detailed analysis was conducted to assess the impact of neutral-point voltage imbalance under HDPWM and highlight the significance of achieving a balanced neutral-point voltage. The experimental results demonstrate that the proposed control strategy can balance the neutral-point voltage while maintaining key advantages such as zero crossing clamping, low switching loss, and low neutral-point voltage fluctuations.