Design and implementation of a single phase grid-connected PV inverter with a new active damping strategy

This paper presents an effective current injection method for a single phase grid-connected PV inverter with LCL filter. The main objective of the proposed control strategy is to compensate the resonance effect of the LCL filter. In the proposed control strategy, a resonance compensator is augmented to the conventional proportional resonance (PR) controller to attenuate current oscillations in resonance frequency of LCL filter. The proposed strategy robustly regulates the output current of grid connected inverter in various grid impedances and provides a high quality current injection capability for the PV inverter in harmonic polluted condition of the grid voltage. The performance of the proposed control scheme is verified by using digital time-domain simulation in MATLAB Simulink environment. Moreover, the proposed scheme has been tested experimentally in the laboratory.