A method to estimate hysteresis torque using core loss

This paper presents a analysis method to estimate the hysteresis torque of a permanent magnet motor using core loss data without hysteresis loop. In the motor which is used in the electric power steering system, the analysis of hysteresis torque is important to predict accurate offset torque including bearing friction. In this paper, hysteresis loss is computed by core loss that is obtained from experiment at low frequencies. Hysteresis torque is calculated as hysteresis loss is divided by motor speed. This method is quite simple than method which use the Preisach model for calculating hysteresis torque. Finally, the validity of this method is verified by the comparison with test results.