LAUSR

In this article, a direct grid-connected servo system without a dc-link capacitor is proposed for multiphase machines. First, the modeling and field-oriented control are elaborated for the direct grid-connected multiphase servo system. Then, the space current vector modulation and the vector coordination under pulsewidth-modulated (PWM) dc-link voltage are introduced, which is to ensure the safe current commutation. Moreover, the torque and harmonic current control are implemented independently with vector space decomposition. Finally, both simulation and experimental results are given to verify the effectiveness and validity of the proposed servo system.