Fault Diagnosis for Permanent Magnet Synchronous Motor With Demagnetization Fault and Sensor Fault

In this article, a fault diagnosis scheme is proposed for a permanent magnet synchronous motor (PMSM) system with multiple fault scenarios. A novel diagnostic framework is designed to specifically address the challenge of coupled demagnetization and speed sensor fault (SSF). First, to decouple the mutual influence of the demagnetization fault (DF) and the SSF and reduce computational complexity, a novel super-twisting sliding mode observer (STSMO) is designed. It estimates the counter electromotive force (CEMF) along the α β-axis with high precision, and then the estimated value is used to recalculate the motor speed, effectively alleviating the cross-impact of multiple faults. Then, a novel sliding mode function is introduced, and an enhanced sliding mode observer (SMO) is designed based on this function. So that the DF and the external perturbation can be estimated simultaneously. Then, a comprehensive system stability analysis is then conducted to verify the convergence of the proposed scheme. Finally, the proposed algorithm is rigorously tested through extensive simulations and experiments. It is demonstrated that the algorithm provides accurate and reliable diagnosis of both the DF and the SSF under different fault severities. ©2024 IEEE.