Online temperature estimation of IPMSM permanent magnets in hybrid electric vehicles

The temperature-rise inside the magnets of interior permanent magnet synchronous motors (IPMSM) in a hybrid electric vehicle (HEV) caused by losses can lead to potential irreversible demagnetization. This paper presents an analytical model of online temperature prediction. Based on the relationship of the temperature and the magnets performance, the temperature of magnets is predicted through solving the equation of voltage, current, rotate speed and winding temperature in the model. The predicted temperatures of the model is validated by experiments when the motors operated by three phase sine supply. And the temperature rises observably under PWM inverter supply. Furthermore, the finite element analysis (FEA) simulation results give more confidence for the proposed estimators.