Carrier Based Loss-Optimized DPWM Method With Current Distortion Suppression and NP Voltage Balance Control for Vienna Rectifiers

Discontinuous pulse width modulation (DPWM) applied to Vienna rectifier faces two challenges: one is how to compromise between reducing switching losses and suppressing input current distortion; the second is how to effectively control the neutral-point (NP) potential. To address these issues, a carrier based loss-optimized DPWM (LO-DPWM) strategy is proposed. By shifting the clamping region of the minimum switching loss DPWM (MSL-DPWM) and injecting zero-sequence components twice, the length of the zero-clamping region is shortened compared to the existing discontinuous modulation method for Vienna rectifier and reduced portion is changed to the clamped phase with the higher absolute input current, which is conducive to further reducing switching losses while ensuring that the input current does not exhibit zero-crossing distortion. Additionally, by adjusting the shift angle, the length of the zero-clamping region can be modified to control the NP voltage balance without introducing additional switching losses. The effectiveness of the proposed LO-DPWM strategy is verified by simulation and experiment. The results indicate that the proposed strategy can eliminate the input current zero-crossing distortion, achieve the optimized system efficiency compared to other modulation strategies, and have the capability of NP voltage balancing control.