An Improved Method of Permanent-magnet Flux Observer for Interior Permanent Magnet Synchronous Motor Based on Adaptive Theory

Permanent magnet synchronous motor is often used as drive motors for electric vehicles. It is prone to demagnetization failure, and the change of permanent magnet flux link is an important basis for diagnosing demagnetization failure of the motor. First, the study establishes a permanent magnet flux adaptive observer and ensures its stability. Then the sensitivity analysis of the main parameters in the observer is carried out. For the parameter with high sensitivity and a large range of variation during motor operation, the expression of flux observation error caused by this parameter change is derived, and the gain matrix in the observation model is optimized. Through simulation verification, the observer can be used for the demagnetization fault diagnosis of the motor.