Harmonic Current Suppression Scheme for Dual Three-Phase PMSM Based on Harmonic Subspace Phase-Shifting Operation

This paper proposes a new harmonic current suppression scheme for dual three-phase permanent-magnet synchronous motor. First, based on the harmonic subspace in the classical vector space decomposition model, the two actual currents under rotating coordinate system are respectively shifted by 90 degrees to construct two virtual currents. Then, by further performing the 6th Park transformation on these actual and virtual currents, the main harmonic current components (5th and 7th) in the motor are naturally converted into four sets of DC values. As a result, there is no need to use any additional filters for harmonic extraction, and harmonic suppression can be achieved through simple proportional-integral control. Consequently, the drawbacks of conventional harmonic suppression schemes based on low-pass filters or resonant controllers can be avoided. Experimental results are provided to verify the effectiveness of the proposed scheme.