A Modified Carrier-Based DPWM With Reduced Switching Loss and Current Distortion for Vienna Rectifier

Carrier-based discontinuous pulse width modulation (PWM) is widely used in three-level ac/dc converters due to its features of higher efficiency and simpler implementation. However, the problems of switching losses, current distortion around zero-crossing points, and neutral-point (NP) voltage fluctuation are mutually coupled for the Vienna rectifier. Therefore, this article proposes a modified carrier-based discontinuous pulsewidth modulation (MCB-DPWM) scheme for the Vienna rectifier with improved zero-sequence voltage injection. The clamping range and clamping mode that suppress zero-crossing distortion are adjusted. Compared to continuous PWM and conventional discontinuous PWM, the proposed MCB-DPWM could effectively eliminate zerocrossing distortion and reduce the NP voltage fluctuation and switching loss, which means higher input current quality and efficiency. Moreover, it features a simpler implementation and less computational burden than space-vector-based PWM. Therefore, it is more suitable for high-frequency applications. Finally, the simulation and experimental results demonstrate that the proposed MCB-DPWM could reduce switching loss and current distortion with lower NP voltage fluctuation under different modulation indices.