Analysis of unbalanced magnetic pull in eccentric interior permanent magnet machines with series and parallel windings

The effects of different winding connections, i.e. series, parallel, and series–parallel combined windings is studied, on the unbalanced magnetic pull (UMP) in an interior permanent magnet synchronous machine (IPMSM) with eccentricity applied. Three types of eccentricities, i.e. static, dynamic, and mixed eccentricities, are investigated. Four types of winding connections are examined and the contributing factors, such as air gap difference, current redistribution, and slot effect on the UMP are analysed. FFT analysis and UMP distribution patterns are used to compare the four types of winding connections. The results show that the current redistribution generated by the parallel connections of the windings results in reduction of UMP for IPMSM with eccentricity.