부산대학교 도서관

Due to big leakage fl ux, the performance of permanent magnet (PM) motor will be much reduced. Especially for surfacemounted permanent magnet synchronous motor (SPMSM) with similar number of poles and slots, because the zigzag leakage fl ux is big and varies with the relative positions between stator and rotor, selecting no-load leakage fl ux coeffi cient with experience may cause a big calculation error to electromagnetic parameters by equivalent magnetic circuit model. Finiteelement method (FEM) can directly calculate the coeffi cient, but entire process is time-consuming. Focusing on this problem, an analytical model of no-load leakage fl ux coeffi cient is proposed including air-gap leakage fl ux model and zigzag leakage fl ux model. Then, an improved subdomain model for magnetic fi eld calculation of SPMSM is established, and the air-gap magnetic fl ux density, inducing fl ux linkage and line no-load back electromotive force (EMF) are calculated considering no-load leakage fl ux. To verify the improved model, an external rotor type SPMSM with 20-poles and 24-slots for bridge crane is designed and manufactured. Finally, the validity of improved model is verifi ed by experimental test.