A Phase Current Reconstruction Method for Open-End Winding Permanent Magnet Synchronous Machine to Reduce Immeasurable Regions of High Modulation

The paper researches on the phase current reconstruction technology of a common DC bus type open-end winding permanent magnet synchronous machine system, and proposes a method to reduce the immmeasurable regions of the medium vector modulation method by alternating the medium voltage vectors. Based on the medium vector modulation method, the paper synthesizes the reference vector by alternating the medium voltage vector with the same effect and using the large voltage vector as an auxiliary to obtain sufficient DC bus sampling time for the control system in the immeasurable regions. The proposed method not only does not increase the additional times of switch, but also adopts a symmetrical modulation method. The method can be implemented based on triangular carriers, which is very convenient for its practical application in digital controllers. By using the method proposed in the paper, the reconstruction of three-phase currents is achieved and the zero sequence current is obtained. Finally, the effectiveness of the method proposed is verified through simulation, further improving the reliability of the system.