Active Zero-Sequence Current Suppression-Based Model Predictive Current Control for Series-End Winding PMSM Drives

Series-winding topology inherits the high DC-link voltage utilization of the open-winding topology while zero-sequence loop still existing. The resulting zero-sequence current (ZSC) will cause additional torque ripple. To this end, the active control of ZSC should be taken into consideration. In this paper, an active ZSC suppression-based model predictive current control scheme for series-winding permanent magnet synchronous machines (SW-PMSMs) is proposed. First, based on the voltage vector (VV) distribution of three-phase SW-PMSM, six VVs without zero-sequence component are chosen as the basic VVs in $\alpha-\beta$ subspace. Next, the virtual VVs are employed to obtain the VVs only containing zero-sequence component, and they are utilized as the basic VVs in zero-sequence subspace modulation. Subsequently, the optimal VVs and their duty ratios in $\alpha-\beta$ and zero-sequence subspaces are selected and calculated separately to track the reference VVs according to the concept of deadbeat control. Next, the optimal VVs under the calculated duty ratios in different subspaces are combined and synthesized to generate switching sequences with constant switching frequency. The proposed scheme realizes the active ZSC suppression of SW-PMSM with current performance improvement. Meanwhile, time-consuming enumeration and cost function calculation can also be avoided. Finally, experimental results verify the proposed scheme and recognize the necessity of active ZSC suppression.