A Flux-Weakening Method for PMSM Based Model Predictive Direct Speed Control

In order to improve the high-speed performance of conventional speed prediction control, expand the speed regulation range of permanent magnet synchronous motor (PMSM). A flux-weakening method-based model predictive direct speed control (MP-DSC) is proposed in this paper. In this control strategy, when the motor breaks through the rated speed and runs in the high-speed area, flux-weakening control is achieved to break through the rated speed by controlling the d-axis reference current, which is applied to obtain reference voltage. Based on the principle of deadbeat control, the cost function of conventional speed prediction control including the speed error and current error is converted into a cost function containing only the voltage error. Thus, the weighting factor in conventional MP-DSC method is eliminated in the proposed method, and the flux-weakening control is implemented in the high-speed operation area. Simulation and experiment results demonstrate the feasibility of the proposed method.