Design and Analysis of Fractional Pole-Pair Permanent Magnet Vernier Machine Using Asymmetrical V-Shaped Permanent Magnet

For the purpose of reducing the cogging torque of permanent magnet vernier machine (PMVM), fractional pole-pair permanent magnet vernier machine (FP-PMVM) is proposed. Firstly, in order to obtain three-phase symmetrical counter electromotive force, analyze the slot vector diagram to estimate the feasibility of the slot-pole combinations in FPPMVM. Secondly, choose the three sections stator segmentation to eliminate the end effect caused by stator segmentation. Then, in order to further reduce cogging torque and improve the load torque, choose the inner rotor featuring the asymmetrical V-shaped permanent magnet (PM) topology instead of surface mounted PM. Finally, FP-PMVM with asymmetrical V-shaped PM, fractional pole-pair surface mounted permanent magnet vernier machine (FP-SMPMVM) and surface mounted permanent magnet vernier machine (SMPMVM) are analyzed by finite element analysis (FEA). The simulation results show that compared to SMPMVM and FP-SMPMVM, the cogging torque of FP-PMVM with asymmetrical V-shaped PM is significantly decreased, while the load torque is also improved.