Large-Airgap High-Speed Permanent Magnet Machines for Flywheel System Applications

This paper investigates the performance of large-airgap high-speed permanent magnet machines for the flywheel energy storage system. The high-speed electric machine in the flywheel energy storage system is placed in a vacuum chamber, and the heat dissipation of the electric machine becomes a key problem in the design of the high-speed permanent magnet machine. This paper investigates the relationship between components of the electric machine loss and electric machine parameters such as airgap length and slot-opening width, and proposes a new type of high-speed permanent magnet machine structure, which can reduce the eddy current loss of the rotor and improve the heat dissipation condition of the stator. According to the FEA results, it can be known that the large-airgap high-speed permanent magnet machine has better heat dissipation performance, which is beneficial to further improve the power level of the flywheel energy storage system.