Hysteresis torque estimation by using iron-loss analysis in permanent magnet synchronous motor

This study presents an analysis method to estimate the hysteresis torque of a permanent magnet synchronous motor (PMSM) with the iron-losses data. In the PMSM, hysteresis losses caused by the permanent magnet can produce an offset torque adding to the cogging torque. Therefore the accurate estimation of hysteresis torque is very important as there are demanding requirements on the torque pulsation and precise control. In the method of this study, first, a group of iron-loss data is measured at low frequency. The hysteresis loss data can be separated from this iron-loss data, by means of the obtained data and numerical methods, then, the hysteresis loss and the corresponding hysteresis torque of the PMSM is calculated. Three different ferromagnetic materials will be tested in this method. Finally, an experiment is processed to demonstrate the accuracy of the proposed method.