Stator Winding Temperature Estimation of IPMSM Based on a High-frequency Voltage Signal Injection

An Interior Permanent Magnet Synchronous Machine, IPMSM, has been widely adopted as a traction motor of electric/hybrid vehicles because of high torque density and wide operating speed region. In the operation of IPMSM, a winding temperature should be monitored to maximize the operating area of IPMSM while avoiding winding insulation breakdown. This paper proposes a stator winding temperature estimation method of IPMSM by using high-frequency (HF) resistance at low operation speed. A relation between HF resistance and the stator winding temperature is analyzed and verified in an experimental setup where the stator winding temperatures and the magnet temperatures can be measured. Based on the relation, the stator temperature estimation method has been devised in this paper. Experimental results, including online estimation, show that the proposed method can be utilized to estimate the stator winding temperature.