Analysis and modeling of open-circuit airgap field distributions in multi-segment and multilayer interior permanent magnet machines

This paper presents the lumped magnetic circuit models for interior permanent magnet (IPM) machines with multi-segment and multilayer permanent magnets. The open-circuit air gap field distribution, average air gap flux density and leakage fluxes are derived analytically. The FEA is adopted to verify the developed models and analytical method. It shows that for the prototype machines, the errors between the FEA and analytically predicted results are ≪1% for multi-segment IPM machines and ≪2% for multilayer IPM machines.