IPMSM Magnet Temperature Estimation by d-axis Flux Linkage

An Interior Permanent Magnet Synchronous Machine, IPMSM, has been widely used as a traction motor in automotive industries for last 10 years thanks to the high torque density and a wide operating speed range. The reliability and torque control accuracy strongly depend on a magnet temperature of IPMSM. D-axis flux had been generally exploited to estimate the magnet temperature, in conjunction with the information of the stator winding resistance, which varies according to its temperature. And in the conventional method, temperature sensors should be attached to the stator windings to decouple the stator temperature effect. In this paper by using the d-axis flux in specific currents, no temperature sensor is required to estimate the magnet temperature. Furthermore, the number of look up table can remarkably be reduced. The proposed method has been verified in the small-scaled experiment set. The performance of the method has been evaluated at various currents, speeds and the magnet temperatures from 3.9 °C to 80.7°C.