Continuous Control Set Model Predictive Control for the optimal current control of Permanent Magnet Synchronous Motors

Abstract

This paper proposes a Continuous Control Set Model Predictive Control (CCS-MPC) for controlling the internal loop of Permanent Magnet Synchronous Motors (PMSMs). The proposed controller has the ability to track the references with zero steady-state error and provides a fast dynamic response. The performance of the internal loop affects the motor currents and torque ripples. The obtained Total Harmonic Distortion (THD) with the same switching frequency is much lower than Finite Control Set Model Predictive Control (FCS-MPC), which is mostly used in controlling the internal loop.The control parameters are selected with a sensitivity analysis to provide a reasonable phase margin and gain margin. Furthermore, to overcome the nonlinearity of the model, the controller is designed beforehand for different speed setpoints, and the control law coefficients are saved in a look-up table. Then, in each sampling time, the speed is measured, the coefficient is interpolated, and the control law is updated.All the optimization of the proposed controller is performed offline and the output is some simple expressions thus the control law is not computationally expensive. In addition, the controller output is voltage in the continuous space that is applied to the inverter by a standard algorithm and works with a fixed switching frequency.The simulation and experimental results are presented to validate the proposed controller’s appealing features.