Improved Control Strategy Combining Deadbeat Predictive Current Control with Disturbance Rejection Feedforward Compensation for Permanent Magnet Synchronous Motor

To promote the performance of current loop of the permanent magnet synchronous motor (PMSM) due to motor parameter mismatch which varies with the load in actual operation, an improved control strategy combining deadbeat predictive current control with disturbance rejection feedforward compensation is proposed. Firstly, a sliding mode load torque observer (SMLTO) is designed to achieve the real time identification of load torque, where speed and load torque are selected as state variables. Besides, integral sliding mode surface is selected as switching surface to combine with the conventional exponential reaching law. Moreover, a novel exponential reaching law with a self-adaptive coefficient that can converge fast is proposed to improve the performance of SMLTO,including the fast convergence of the speed error and the estimated load torque, as well as restraining the chattering of the estimated load torque. Finally, the estimated load torque will be compensated feedforward to the current controller to compensate the disturbance caused by motor parameter mismatch and the load torque variation. Hence, the rate of convergence of currents and electromagnetic torque will be further improved and the chattering of the estimated load torque will be further restrained. Numerical simulation results show that the system can operate stably regardless of nominal parameters or mismatch parameters when the improved strategy is adopted. Compared to the conventional strategy, the overshoot when increasing load is decreased by about 5 %,the overshoot when decreasing load is decreased by about 10 % while the response time is decreased by about 0. 02 s when stator inductance attenuates. The overshoot when increasing load is decreased by about 6. 31 % , the overshoot when decreasing load is decreased by about 10. 67% while the response time is decreased by about 0. 02 s when stator inductance attenuates and resistance increases. And there will be smaller chattering, the anti-disturbance of the system is further improved. © 2022 Xi'an Jiaotong University. All rights reserved.