Robust Cascaded Model-Free Tolerant Control with Parameters Mismatch Fault Diagnosis for PMSM Drive System

Since the parameters mismatch fault caused by the mismatch between motor parameters and model predictive controller parameters can seriously affect the performance of the drive system, it is necessary to investigate parameters mismatch fault diagnosis and tolerant control. In this study, a novel robust cascaded model-free tolerant control(RCM-FTC) method with parameters mismatch fault diagnosis is proposed for permanent magnet synchronous motor(PMSM) drive system, which can effectively improve the control performance of stator flux and torque under parameters mismatch fault. The parameters mismatch fault sensitivity of the PMSM drive system are analyzed, and a novel ultralocal model is established under parameters mismatch fault. The multivariable integral terminal sliding mode observer (MIT-SMO) with improved sliding mode reaching law is designed to diagnose parameters mismatch fault and identify operating states in PMSM drive system. The robust cascaded speed loop and stator flux loop control strategy is proposed for parameters mismatch fault by utilizing the model-free sliding mode control algorithm, which can eliminate the impact of parameters mismatch fault on the PMSM drive system. The test results demonstrate the effectiveness of the proposed RCM-FTC method in significantly eliminating stator flux/torque ripple and improving fault tolerance capabilities in the case of parameters mismatch fault.