Three-phase four-wire grid-connected PV power supply with accurate MPPT for unbalanced nonlinear load compensation

This paper presents a three-phase four-wire grid-connected photovoltaic (PV) system to play as a power generator and active filter (AF) compensator. This system is flexible enough to efficiently remove current harmonic components and balance the line currents drawn from grid by an unbalanced nonlinear load. Simultaneously power conversion system injects the maximum power available from the PV array to the grid by using a fast and precise control strategy. The controller enjoys both modified PQ0 transformation and Fuzzy Logic Incremental Conductance (FL-IC) method to accomplish the Maximum Power Point operation Tracking (MPPT) of PV array. The control strategy is described and the whole system is built and simulated by PSCAD/EMTDC software with reference to different operation conditions. The results from simulations confirm the theoretical aspects of the proposed PV power supply and effectiveness of the control techniques to compensate non-linear unbalanced loads as well as utilization of the maximum PV power production.