Current Control of a Grid-Connected Single-Phase Voltage-Source Inverter with LCL Filter

The control in power electronic systems play an important role in the connection of renewable energy sources to the electrical grid. This paper presents the design of a current control for a grid-connected single-phase voltage source inverter (VSI). The VSI is connected to the grid through an LCL filter in order to attenuate the switching harmonics in the output signal. The proposed control provides an active damping at the resonance frequency and tracks the current reference with a fast dynamic response. The control scheme is based on a resonant regulator implemented in a structure with two nested controllers. The proposed control ensures a direct pole-placement of the closed-loop transfer function without the need for state observers and only measuring the grid current. Simulation results assess the validity of the control method.