High-Resistance Fault Control in Permanent Magnet Synchronous Motors

A difficult problem of a high-resistance (HR) connection for permanent magnet synchronous motor (PMSM) drives is investigated in this article. The presence of HR affects stator currents in such a way to deviate from their reference currents in the vector-control structure of the drive, which degrades the performance, reliability, and efficiency of the system. Unlike existing schemes, which are limited to detection of the HR connection, in this article, a current-control scheme based on a higher order sliding mode is designed to not only detect, but also provide fault-tolerant control simultaneously. The HR connection control is obtained by canceling extra dynamics (which are generated due to the HR connection) in the considered PMSM current model, which provides accurate tracking of actual current dynamics (d,q) to the reference currents. Moreover, the HR is also estimated from the robust sliding-mode control terms to monitor the asymmetry in the faulted phase. Simulation and experimental results on a three-phase laboratory test PMSM confirm the validity of the proposed scheme for various cases of stator phase resistances.