Decoupled Estimation of Resistance and Permanent Magnet Temperature of Permanent Magnet Synchronous Motor Based on Current Angle Injection

This paper presents a decoupled temperature estimation method for the resistance and permanent magnet of a permanent magnet synchronous motor (PMSM) based on current angle injection. A decoupled model of resistance and permanent magnet is constructed based on the motor voltage model. By injecting a high-frequency current angle and using a low-pass filter to extract the temperature-related terms from the high-frequency response, the decoupled estimation of winding temperature and permanent magnet temperature is achieved, effectively reducing the dependence of temperature estimation on parameters and the influence of noise on estimation. In the constructed estimation model, the estimation of winding temperature and permanent magnet temperature is decoupled, improving the accuracy of temperature estimation. Moreover, the temperature-related terms only contain the cosine value of the current angle, ensuring a high signal-to-noise ratio under low current angle conditions and enhancing the anti-interference ability of temperature estimation. The effectiveness of the proposed method is verified through simulation and experiments.