A Predictive Control Method for High Bandwidth and Robust Fault-Tolerant Current of PMSM

A two-step predictive current control method based on a predictive evaluation function and a sliding mode observer is proposed to improve the current bandwidth and dynamic performance of servo systems with permanent magnet AC servo system. Firstly, a predictive evaluation function is designed to obtain the optimal voltage vector and to attenuate the current fluctuation in the existing two-step predictive current control caused by system noise. Then, a sliding mode observer is designed based on a stator voltage equation with parameter perturbation and a new switch function. When the gain matrix of the observer is selected properly, the observed equivalent current error converges to the current prediction error caused by mismatch of the electrical parameters, and the corresponding voltage is compensated and corrected according to the equivalent current error. The q-phase current step response experiment with the amplitude of 3 A, the current loop bandwidth test and the controller robustness test are carried out on a motor control performance testing platform. Results show that the proposed control method effectively improves the dynamic response performance and the bandwidth of the current loop of permanent magnet synchronous motor (PMSM), and has sufficient robustness. © 2020, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.