Principle of Operation and Magnetic Circuit Analysis of a Doubly Salient Homopolar Motor for Flywheel Energy Storage Systems

Flywheel energy storage system has a good development prospect in the field of new energy because of its features such as high efficiency and environmental protection. The motor, as the core of the energy conversion of such energy storage systems, is related to the reliable operation of the whole system. In this paper, a new type of motor suitable for flywheel energy storage system is designed, based on the doubly salient motor, changing the distribution position of the permanent magnets, and realizing the combination of the homopolar structure and the doubly salient structure. During power generation operation, the direction of the magnetic field within the rotor will not change due to changes in the relative positions of the stator and rotor during rotor rotation. Moreover, the cogging torque generated by this motor is very small and has little effect on the normal operation of the motor. The motor has a simple structure and manufacturing process, is highly reliable, and is suitable for high-speed operating environments. In this paper, a three-dimensional finite element simulation analysis of the motor is carried out, and the simulation results show that the motor has good static and dynamic characteristics, which verifies the feasibility of the design of this type of motor.