Modular Winding Arrangement Design to Suppress Short-Circuit Current and Magnetic Coupling in PM Machines for Flywheel Battery

Due to the advantages of long life-period and environmental friendliness, the flywheel battery is widely concerned. In this paper, a modular winding arrangement is proposed to suppress the short-circuit current (SCC) and magnetic coupling of permanent magnet (PM) machines for flywheel battery. Firstly, the design principle of the modular arrangement is elaborated. Then, the magnetomotive force (MMF) harmonic components in the conventional and modular arrangement are derived through winding spatial distribution. Afterwards, the inductance expression is obtained according to winding function theory. Furthermore, the inversely proportional relationship between self-inductance and SCC are deduced. Then, the finite element method (FEM) is adopted, which verifies that the modular winding arrangement has the advantage of SCC and magnetic coupling suppression in PM machines for flywheel battery. Finally, a five-phase PM machine and the proposed modular arrangement machine, and the experiments are carried out for theoretical verification.