Zero-Sequence-Current Suppression of Open-End Winding PMSM With Common DC Bus Based on Virtual Vector Control

This article presents a novel zero-sequence-current suppression method for open-end winding permanent magnet synchronous motor. First, a pair of orthogonal dc signals proportional to the amplitude of the zero-sequence-current are detected through the orthogonal gate-integral circuit, which will be regarded as the projection of the zero-sequence-current on the three times synchronous rotating coordinate system. Second, by imitating the idea of vector control, the two projections are tracked respectively, and two orthogonal voltage components are obtained. Finally, the zero-sequence-voltage for compensating the zero-sequence-current is obtained by performing synchronous rotation inverse transformation on the two voltage components. The algorithm is simple and can realize the error-free tracking of the zero-sequence-current by common PI regulator. It can not only significantly improve the suppression accuracy of zero-sequence-current, but also reduce the design difficulty of the controller. The experimental results verify the effectiveness and feasibility of this strategy.