Active and reactive power decoupling control of grid-connected inverters in stationary reference frame

Proportion resonant(PR) controllers are able to achieve zero steady-state error for AC input signals and are widely used for simplifying control systems in the stationary reference frame. However, power decoupling in the stationary reference frame with a PR controller has not been investigated thoroughly. Based on the complex vector model of a grid-connected inverter(GCI), this paper deduces theoretically the power coupling relationship of GCI with the traditional PR current controller. A modified PR controller is provided for achieving the power decoupling, and the design method of the controller is presented. Simulation and experimental results verify that there is coupling between active and reactive power using the traditional PR controller and the proposed method can realize the power decoupling.