Nonlinear model predictive control of permanent magnet linear synchronous motor

Abstract

Field oriented control (FOC) is considered as one of the most efficient techniques for speed tracking problem of permanent magnet linear synchronous motor (PMLSM) drives. However, the main inherent drawbacks of classic FOC methods are the high sensitivity to machine parameters, high switching frequency and unsuitable performances in tracking low speeds. In this paper, a new strategy based on nonlinear model predictive control (NMPC) is proposed to overcome the limitations of cascaded linear controllers and other problems inherent in classical controllers. The suggested controller directly controls the switches of inverter. In order to show the efficiency of the proposed control strategy, the system response is studied under uncertainty of the motor parameters and load disturbance. To more validations, the intense reduction of inverter switching frequency is studied in compare with well-known FOC scheme. The simulation results show that the proposed approach has as well tracking of speed trajectory under all operating conditions, and simultaneously, it reduces the average inverter switching frequency 90% rather than the classical FOC.