Control scheme for 3-phase PWM AC/DC converter considering unbalanced input voltage

Generally, the control of a three-phase PWM AC/DC power converter has been implemented in the synchronous frame model because the synchronous frame controller can eliminate effectively steady state errors and has fast transient response characteristic by decoupling control. However, most of such controllers have been designed under balanced input voltages. Therefore, such designed controllers have input current harmonics and DC-link voltage ripple under unbalanced input voltage conditions. In this paper, the proposed scheme is designed to regulate the synchronous frame input voltage considered as an input side back-EMF component (Ed, Eq) according to input voltage condition. And current reference is selected to eliminate the reactive power and the harmonic active power. This scheme is simple and minimizes effectively the harmonic components in input and output system under unbalanced input voltage condition