A Zero-Sequence Component Injection Modulation Method With Compensation for Current Harmonic Mitigation of a Vienna Rectifier

Owing to the operational characteristic of a Vienna rectifier, it is found that the traditional modulation method would result in the current distortion. This paper, therefore, proposes a novel zero-sequence component injection modulation method for improving the input quality of the Vienna rectifier with balanced or unbalanced dc-link voltages. In specific, the degree of unbalanced dc-link voltages increases the size of abnormal regions in a slant and asymmetrical space vector diagram, which leads to more serious current distortion. The proposed method identifies the abnormal intervals by average duties accurately without detecting the position of the reference vector. Considering the operational characteristics, three-phase compensation components are calculated respectively depending on an unbalanced factor and added to three-phase average duties in abnormal intervals. As a result, the current harmonics of the Vienna rectifier are mitigated significantly with balanced or unbalanced dc-link voltages. The effectiveness and the performance of the proposed zero-sequence component injection method for the Vienna rectifier are verified by simulation and experiments.