Improved model predictive control of permanent magnet synchronous motor with duty ratio optimization and cost function correction

Abstract

This paper presents an improved model predictive control (MPC) for permanent magnet synchronous motor (PMSM) drives. The proposed MPC is different from the conventional MPC in applying two voltage vectors in every control period. The duty ratio is firstly calculated using a simple but effective method with the consideration of the one-step delay. The cost function is then modified by incorporating the duty ratio, thus to calculate the optimal voltage vector applied in every sampling period. Based on the improved MPC, the elimination of weight factor k1 and the compensation of stability factors are further proposed to further correct the cost function. Test results show that the proposed control strategy contributes to lower torque and flux ripples, faster dynamic response, better start-up response compared to the conventional MPC.