Irreversible demagnetization is one of the drawbacks of permanent magnet synchronous machines (PMSMs). This article first investigates the influence of uneven demagnetization fault on the current control of surface-mounted PMSMs with fractional-slot winding configurations. The characterization of permanent magnet flux linkage under rotor fault is presented by means of two-dimensional finite element analysis in a 12-slot/10-pole surface-mounted PMSM, and the mathematical model containing interharmonics is built. Then, a proportional-integral-resonant (PIR) current controller is introduced to suppress the interharmonics and reduce the undesired harmonic losses. Finally, experimental results are presented to prove the effectiveness of the proposed method.

current harmonic suppression;uneven demagnetization;permanent magnet synchronous machine (PMSM)