A novel feedback-based control for PWM AC/DC converters under unbalanced grid conditions

Under unbalanced grid conditions low order harmonic appears both at the DC output and AC inputs of the converter. Such harmonics lead to deterioration of performance of the system. This paper presents a novel feedback-based controller, which regulates directly converter voltages to eliminate of the 2nd ripple of DC link voltage to alleviate the stress of DC-link capacitor and to reduce the 3rd harmonic of input AC currents. The results show excellent response and stable operation of the PWM converter using the proposed novel control method.