A novel time varying dynamic modeling for hysteresis motor

Abstract

Hysteresis motors are used in special applications such as gyroscope and gas centrifuge due to their unique features such as synchronism, self-starting, and developing smooth torque. Dynamic modeling of hysteresis motors is essential to the prediction of the transient performance, the study of the dynamic stability, the development of modern closed-loop control, and the estimation strategies. This paper develops a new time varying dynamic model for a high-speed, circumferential-flux type hysteresis motor, in which the parameters of equivalent circuit of rotor's material are adjusted based on operational B-H loop. For this purpose and based on the elliptical assumption about B - H loops, the hysteresis lag angle, fi, is updated due to the applied stator voltage and available load torque. Developed mathematical model satisfies many theoretical aspects of hysteresis motor behavior in transient and steady-state situations. The model offers a tool to study the start-up of hysteresis motor, the change of stator voltage, the variation of load torque, the frequency tracking of variable-speed applications, and transient-state response to design parameters. Some simulations are provided to demonstrate the validity of developed model in Matlab/Simulink and are verified by some experimental results. The proposed results verify the advantages of this model over previous research works.