A Novel Hybrid Hysteresis Motor with Multi-Stack PM-Hysteresis Rotor; General Modeling, Analysis and Design Optimization

Simple and robust structure, self-starting and smooth operation with low noise and vibration are the most attractive advantages of the Hysteresis Motor (HM) which makes it suitable for high speed constant torque applications. High magnetizing current and low efficiency and power factor are the major drawbacks of the conventional HMs. On the other hand, the PM motors are widely used because of high efficiency, high power factor and relatively high stability at synchronous speed. However, PM motors suffer from having no starting torque and generating considerable oscillating torque. This paper presents a novel Multi-Stack PM-Hysteresis Motor in order to improve the performance characteristics of the conventional HM. In the optimal design procedure, the electrical equivalent circuits (EECs) are used for evaluating the operating parameters. A multi-objective optimization using Imperialist Competitive Algorithm as the solver is established for improving the efficiency and power factor of the machine as well as reducing the rotational inertia, overall volume and speed oscillations, simultaneously. The feasibility of the designed machine is guaranteed by considering the electrical, mechanical, magnetic and the thermal constraints. Finally, the appropriate performance of the optimized structure is validated using 2D time-stepping finite element analysis.