Analytical and Finite Element Analysis for Demagnetization Fault of External Rotor PMSM

Various factors can lead to the demagnetization of permanent magnets, such as excessive magnetomotive force and/or high operating temperatures. As a result, the machine's flux density distribution is no longer uniform, producing new fault harmonics and reducing motor efficiency. In view of this problem, this paper presents the behavior of an external rotor permanent magnet synchronous machine in the presence of a total demagnetization fault in two adjacent magnets. The machine's performance will be evaluated using an analytical model that has been developed. Finite element analysis and experiment tests are used to validate the feasibility of the proposed analytical model.