Thrust ripple reduction of linear flux-switching PM motor using harmonic injected current

The linear flux-switching permanent-magnet (LFSPM) motor offers high power density, high efficiency and low cost, suitable for urban rail transit applications. However, due to its significant detent force induced by both slot-effect and end-effect, this motor still suffers from severe thrust ripple. In this paper, a new thrust ripple minimization approach is proposed, in which the proper harmonic current components are injected into the fundamental current. As a result, specific force component is produced to counteract the dominant harmonic cogging force, in such a way that thrust ripple remains minimum. Simulation results confirm that the proposed method can effectively suppress the thrust ripple.