Performance Analysis of Robust Reference Current Tracking Controllers for Single Phase LCL-type Grid Connected Converter through Active Damping Approach

The LCL filter plays a major role to attenuate the switching frequency harmonics due to the power electronic converter. Furthermore, LCL Filters are naturally resonant which affect the stability of the system. To tackle the resonance problem, generally passive damping methods are a simple and straight forward solution but it effects the efficiency due to the insertion of resistance in LCL components. It is important to explore the alternatives for the passive damping methods to improve the overall system efficiency. This paper presents, the design of reference current tracking controller based on the LCL filter Capacitor feedback current using active damping approach. Active damping technique used in the proposed controller helps to suppress the resonant peak and injects high quality power into the grid. Further, the impact of LCL filter parameters on robustness of the proposed controllers is studied. Finally, performance of the proposed resonant controller is compared with the existing PI controller through MATLAB simulations.