Analysis and Suppression of Negative-Sequence Current in Single-Channel Operation of Dual Three-Phase PMSM With Zero Angle Displacement

In high-power applications like wind power generation, dual three-phase permanent-magnet synchronous machines (PMSMs) with two power conversion channels grow in popularity owing to decent fault-tolerant capability. This letter focuses on the current control of dual three-phase PMSMs with zero angle displacement, particularly in scenarios where one channel experiences a malfunction. The influence of asymmetric mutual-inductances on negative-sequence current is investigated. Subsequently, a harmonic control method based on non-integer sliding discrete Fourier transform is proposed to suppress the undesired current harmonics. No additional parameter tuning or digital filters are required, which facilitates engineering implementation and integration. Experimental results on a down-scaled drive system validate the effectiveness of the proposed method.