Study of Magnetic Coupler With Clutch for Superconducting Flywheel Energy Storage System

High-temperature superconducting flywheel energy storage system has many advantages, including high specific power, low maintenance, and high cycle life. However, its self-discharging rate is a little high. Although the bearing friction loss can be reduced by using superconducting magnetic levitation bearings and windage loss can be reduced by placing the flywheel in a vacuum environment, the energy of the system will still be consumed by itself. This is mainly caused by the no-load losses of the generator/motor. In this article, a magnetic coupler with a clutch function is designed to connect the flywheel and generator/motor. Torque transmission can be turned off with the clutch operation to remove the no-load loss of the motor in the energy retention stage. The equivalent magnetic circuit analysis model and finite element simulation are constructed for this kind of clutch. The flux distribution and torque transfer of this kind of magnetic coupler under different states are studied. The established models provide an effective means for the optimized design of the coupler.