Design of current controller for 3-phase PWM converter with unbalanced input voltage

Abstract

Generally current controllers of three-phase PWM power converters have been implemented in the synchronous frame because the synchronous frame controller can eliminate steady state error and has fast transient response by decoupling control. However most of such controllers have been designed under balanced input voltage. Therefore such designed current controllers showed undesirable current control characteristics under unbalanced conditions because the current reference is distorted by the second order harmonic voltage due to negative sequence. In this paper, a current controller for a PWM power converter, considering unbalanced input voltage, is designed and verified by both simulation and experiment.