An Improved Carrier-Based Discontinuous PWM Method with Phase-Current THD Reduction for Vienna Rectifier

This paper proposes an improved CB-DPWM(Carrier-Based Discontinuous Pulse Width Modulation) method for the Vienna rectifier. The conventional CB-DPWM methods clamp the reference voltage to zero during intervals where the Vienna rectifier's normal operating condition is not met due to the offset voltage for DPWM operation. However, these additional clamping intervals cause an increase in the phase current THD(Total Harmonic Distortion). In this paper, an improved CB-DPWM method is proposed to reduce the phase current THD of the Vienna rectifier by minimizing intervals where the reference voltage is zero. Furthermore, neutral point voltage control can be applied in the non-clamping regions to mitigate fluctuations in the neutral point voltage. Consequently, the proposed method can enhance the phase current THD while maintaining the advantage of reducing switching losses. The effectiveness of the proposed method is verified through simulations and experimental results.