Open circuit magnetic field calculation of the V-shaped interior PM machine with non-uniform air-gap

An analytical method for open circuit magnetic field prediction of the V-shaped IPM machine with non-uniform air-gap is proposed in this paper. The machine is divided into five types of regions, including rotor slot, magnetic barrier, air-gap, stator slot and stator slot opening. The magnetic barrier, stator slot and stator slot opening are directly simplified into simple fan-shaped subdomains. By comparison, the air-gap is divided into a set of fan-shaped subdomains. The division method is precisely delineated. Similarly, the rotor slot is divided into multiple fan-shaped subdomains. Then the subdomain method is adopted to predict the magnetic field of IPM machine. The proposed method is implemented on 6p/36s IPM machine, and exhibits good agreement with the FEM and experiment results. This method also applies to magnetic field prediction of the uniform air-gap machine.