Rotor design to improve dynamic performance of axial flux hysteresis motors

Abstract

In high-speed axial flux hysteresis motors (AFHMs), the hysteresis ring and the hysteresis ring holder have the main roles of producing hysteresis torque in steady state and eddy current torque at sub-synchronous speed, respectively. In conventional AFHM, and especially in the high-speed AFHM types, the hysteresis ring holder is placed between the hysteresis ring and stator to produce more eddy current torque at the time of starting. Since the minimum magnetic air gap can cause better motor performance, the previous research exchanges the hysteresis ring place and its holder. However, it has worst motor dynamic response as a result. To cope with these issues, a new model is proposed in this study. A thin copper piece is attached at the bottom of the hysteresis ring to improve the eddy current torque and consequently motor dynamic response. Then finite element analysis is done in order to acquire the accurate copper thickness and investigate the new proposed AFHM. Furthermore, experimental setups are provided and AFHM results in all cases are measured. The obtained test and simulation results show that the new proposed model make a better dynamic performance for the AFHM.