A novel flywheel energy storage system: Based on the barrel type with dual hubs combined flywheel driven by switched flux permanent magnet motor

Abstract

With the challenges of global carbon emissions and climate warming, energy recovery and reuse are becoming very important. Flywheel energy storage system (FESS), as a kind of energy storage systems (ESSs), can effectively convert electrical energy and mechanical energy to accomplish energy recovery and reuse. Additionally, the FESS has the characteristics of pollution-free, high energy, high efficiency, and durability. Thus, a novel FESS is proposed for the configuration, metal material and structure, and driving motor (M/G) to contribute to the development of FESS. First, the novel FESS is made of the metal materials rather than the carbon fiber, reducing manufacturing difficulty and cost. Second, the structure of dual hubs combined flywheel is designed to reduce the mass and obtain a larger moment of inertia, achieving higher energy storage. Third, a 12/10 switched flux permanent magnet motor (SFPM) with an outer rotor structure is designed to replace the conventional permanent magnet synchronous motor (PMSM) and is used as the M/G to achieve excellent operation performance. Finally, the barrel type of the configuration makes the novel FESS more compact and facilitates the realization of a vacuum chamber to remove the windage. Undoubtedly, the novel FESS is designed through the theoretical calculation of energy storage, structure strength and modal analysis, and M/G performance simulation. Accordingly, the novel FESS has a maximum speed of 13,500 rpm, storage energy of 20 kWh (discharge depth 99%), and the longest power consumption time of 2 h. Equally, a prototype is manufactured and tested. Consequently, the results testify the mechanical properties are excellent, the charging and discharging action is stable and rapid.