A Pre-filtering based Current Control Strategy in Grid-tied Photovoltaic Systems with Active Power Filter for Harmonic Mitigation

This paper presents frequency adaptive pre-filtering (FAPF) based an adaptive current control strategy in grid connected photovoltaic (PV) system with active power filter for harmonic mitigation at the distribution terminals. The proposed technique is used in the presence of steady state, voltage sag, voltage swell, load removal, unbalancing and distorted grid voltages conditions. A FAPF strategy employed through the dual second order generalized integrator (DSOGI). The performance of the proposed control scheme is examined under grid distorted, unbalancing and other transient conditions. Furthermore, the performance of the controller found good, more accurate and fast in nature. The current and voltage harmonics are eliminated by using FAPF scheme by using the differentiated frequency locked loop (dFLL) in the system which is also compute the estimated system frequency which gives as feed back to FAPF in the proposed controller. The fuzzy logic proportional integral derivative (FLPID) controller is used to synchronize the DC bus voltage constant at the DC voltage regulator. The proposed adaptive current control strategy is notably improves the system performance in the presence of unbalancing, distorted and steady state conditions. The system is implemented through MATLAB R2014a software and the simulation outcomes are proved via FPGA based real-time platform using vertex-7 VC-707 evaluation kit.