Modeling and analysis of an LCL filter for grid-connected inverters in wind power generation systems

This paper presents the modeling and analysis of a three-phase grid-connected wind energy conversion system using Matlab. The modeled system is characterized and analyzed for validation. An inverter control algorithm for effective power control is also proposed and evaluated. An LCL filter is designed to reduce the switching frequency ripple. But the LCL filter also makes the system unstable because of the zero impedance at the resonant frequency. Two current-loops with PR control strategy are analyzed in this paper to make sure the stability of the system. All analysis and evaluation have been conducted for a 3.5 kW power system with 208V grid voltage.