Finite-set Model Predictive Current Control for Variable-flux Memory Machine Drives with a Three-stage Optimization Strategy

This paper proposes a novel finite-set model predictive current control (FS-MPCC) method for variable flux memory machine (VFMM) drives with a three-stage optimization strategy. A geometric modulation method is proposed for the sake of extending the control set, by which, the number of options is extended from 7 to 193. In order to reduce the computation burden, a three-stage optimization strategy is proposed, which is composed of three parts, i.e. determining the sector, narrowing the targeted range and selecting the optimum vector. By the proposed strategy, only 9 vectors are associated with the current prediction and the cost function calculation. On this basis, a duty-cycle solving algorithm is utilized to further improve the steady-state performance of the investigated VFMM. Finally, simulation results are presented to verify the proposed method.