Current Inner Loop Design Considering Inductance Asymmetry for PMLSM Drives

The three-phase inductance asymmetry is the unique electrical characteristic of permanent magnet linear synchronous motor (PMLSM). To investigate the effect of the inductance asymmetry on the thrust of PMLSM, the accurate motor model considering the inductance asymmetry is deduced. Based on the accurate model, a simple feed-forward current compensation method is proposed to suppress the thrust fluctuation caused by the inductance asymmetry when the load is large. The high performance deadbeat predictive current control (DPCC) algorithm is adopted to ensure the effect of the thrust fluctuation suppression. The effect of the inductance asymmetry on DPCC is theoretically analyzed to determine the DPCC control law. The simulations verify the validity of the theoretical analysis about the inductance asymmetry and the effectiveness of the proposed current inner loop design based on the robust DPCC.