Non-Invasive Magnet Temperature Estimation in IPMSM by High Frequency Pulsating Sinusoidal Voltage Injection

摘要

An Interior Permanent Magnet Synchronous Machine, IPMSM, has been widely employed as a traction motor in automotive industries because of a high torque density and a wide operating speed range. In the traction application, a torque accuracy and an irreversible demagnetization of a permanent magnet are crucial issues for the controllability and reliability of the vehicle. These issues strongly depend on a magnet temperature of IPMSM. In this paper, a method to estimate the temperature of the magnet is derived by analyzing high frequency inductance of IPMSM. The high frequency resistance was generally used to estimate the magnet temperature in the low speed in conjunction with the information of the stator winding resistance. In here, the winding temperature should be measured by sensors on the stator side to decouple the stator winding resistance from the high frequency resistance. However, the proposed method in this paper exploits high frequency inductance as an indicator of the magnet temperature, and it does not need any sensor not only in rotor side but also in stator side. Hence, the method is truly noninvasive. The proposed method has been verified in the small-scaled experiment set. The performace of the method has been evaluated at various torque, speed and the magnet temperatrues from -24°C to 82 °C.