Torque ripple minimization of flux-controllable stator-permanent-magnet brushless motors using harmonic current injection

Due to the nature of salient poles in both the stator and rotor, the new class of flux-controllable stator-permanent-magnet brushless (FC-SPMBL) motors still suffers from severe torque ripples. In this paper, a new torque ripple minimization approach, namely, the harmonic current injection method, is proposed and implemented in the FC-SPMBL motor. By injecting proper harmonic current components into the fundamental current, the variation of instantaneous power is kept to minimum. Thus, the torque ripple is minimized. Both simulation and experimental results show that the proposed approach can effectively suppress the torque ripple.