New proportional resonant control scheme for Grid connected Inverters under Unbalanced and Distorted Grid Conditions

Abstract

This paper deals the grid voltage, especially grid voltage under balanced, unbalanced and harmonically distorted grid conditions, often distorts the injected currents of grid-connected inverters. To address this problem, a robust control scheme of grid-connected inverters is presented in this project. The proposed control scheme employs open-loop filtering technique to offer exact steady-state performance as well as fast transient response. The proposed resonant controller is developed for the inner current control loop of the system. The proposed controller has the ability to track ac current with zero steady-state error. The outer dc-link voltage control loop is developed through the indirect vector control method at synchronously rotating reference frame. The control scheme ensures improved performance of the system at variable load disturbances. The control scheme is implemented in MATLAB–SIMULINK environment.