Mitigation of current harmonics in wind turbine system at distribution level using shunt active filters

To overcome the demand of electricity, the Renewable Energy Sources (RES) are used efficiently. It is also used as a substitute for fuels but produces some power quality problems. In this paper, three phase three wire grid connected inverter with control strategyis discussed in the proposed work. Here the inverter is used for multi-purpose where it is used as an active filter and an interfacing RES with grid. It also acts as a shunt active power filter to compensate the current harmonics produced because of the three phase unbalanced load. With such control, the combination of three phase three wire linear and nonlinear unstable load system and grid connecting inverter at the Point of Common Coupling (PCC) represents as balanced load to the grid. Unity Power Factor (UPF) is achieved at balanced sinusoidal current through the controlling of current controlled inverter, which enables grid to supply or get sinusoidal and balanced power at UPF. The grid connecting inverters analyzed here have three conditions: (i) For P_RES <; P_L, it acts as rectifier. (ii) For P_RES=0, it behaves as shunt active filter. (iii) For P_RES> P_L, power injected to the grid. Role of the grid connecting inverter as an active filter and injection of power under various conditions are explained in this paper. The control strategy was simulated using MATLAB Simulink and the output was verified.