Analysis of radial forces in 100kW IPM machines for ship considering stator and rotor eccentricity

The purpose of this paper is to provide the radial force and vibration mode comparison between two large interior permanent magnet machines (IPM) with different pole-slot combination considering stator and rotor eccentricity. Due to the punching tolerance, the mixed eccentricity of air-gap is inevitable. It will generate the asymmetric magnetic flux density in air-gap, which makes the unbalanced magnetic pull and vibration. The study is focused on the unbalanced magnetic force and their harmonics according to eccentricity condition such as static, dynamic and mixed. When the high vibration is produced especially resonance, the obtained results provide a clue what eccentricity condition occurs in the machine.