Control of unbalanced voltage PWM converter using instantaneous ripple power feedback

The voltage unbalance can impair a PWM converter system because the input active and reactive power ripples are generated by the cross products of line currents and unbalanced voltages. In this paper, effects of voltage unbalance in a three phase PWM converter are analyzed and a new control scheme to suppress input power ripple and DC link voltage ripple caused by unbalances is presented. The proposed method is based on the instantaneous power theory to compute compensation currents which cancel the power ripple. The simulation and experimental results are presented to verify the feasibility and effectiveness of the proposed method.