Comparative Analysis of Variable Leakage Flux PM Motors with Different Flux Barriers

In this paper, the variable leakage flux (VLF) PM motors with three different distributions of flux barriers are designed, analyzed, and compared. First, a feasible approach of realizing leakage flux variation is discussed to emphasize rotor design of different flux barriers, where the variable magnetic resistance is purposely introduced. Then, the three VLF PM motors with different saliency ratio characteristics are investigated and compared comprehensively, including no-load back-EMF, flux density distributions, inductances characteristics, torque production and leakage flux ability. By comparison, a prototype motor with three layers of independent leakage flux bypasses is manufactured and tested, which possessing higher output torque, lower risk of demagnetization, and wider speed range. Finally, the effective design of the proposed motor is verified by experiment.