A Direct Harmonic Current Suppression Technique for Dual Three-Phase PMSM System

Due to the small equivalent impedance in harmonic loop, the harmonic currents in dual three-phase permanent-magnet synchronous machine system are relatively large, which would lead to the serious distortion of phase currents and extra system loss. Hence, the suppression of harmonic currents is indispensable. To further improve the suppression performance, the simplified technique is proposed. In the proposed technique, two variable virtual voltage vectors, which are dynamically determined by the reference voltages, are designed and applied in modulation process, under both the fundamental related sub-plane and the harmonic-related sub-planes. The novelty of the proposed technique is that the modulation implementation is greatly simplified while the harmonic currents are effectively suppressed, compared with the previous methods. Finally, the effectiveness of the proposed technique is validated through the experimental test.