Control design and dynamic analysis for three phase PWM rectifiers under unbalanced voltage dips conditions

The goal of the control strategy for three-phase pulse width modulation (PWM) rectifiers operating under unbalanced voltage conditions is to avoid ripple in the DC-link voltage and harmonics in the input AC currents. A stationary frame control scheme which regulates the instantaneous active power at the converter poles for minimizing of input/output harmonics is used. The design of the control loops involved in this control strategy is provided in this paper. Furthermore, a dynamic analysis of the PWM rectifier operating under balanced and unbalanced voltage operating conditions is performed. The analysis is supported by experimental results for a 20 kVA PWM rectifier prototype. Fast dynamic performance with small DC-link voltage ripple and input sinusoidal currents are obtained with this control scheme even under severe voltage dips operating conditions.