Fault-tolerant Control for Demagnetization Faults in Permanent Magnet Synchronous Machine

Abstract

This paper presents a fault-tolerant control method based on the on-line detection of flux linkage, which can effectively solve the problem of permanent magnet demagnetization faults in the permanent magnet synchronous motor (PMSM). In order to analyze the effect of the permanent magnet flux linkage demagnetization on the PMSM, the mathematical model of demagnetization faults is established. Then, a real-time estimation equation for permanent magnet flux is established based on the equivalent control principle of sliding mode variable structure, whereas the observer is designed based on sliding mode variable structure. Meanwhile, the fault-tolerant control method of maintaining the air magnetic flux of PMSM constant is proposed under the current constraint conditions.