Development of power flow controller for grid connected renewable energy sources using lyapnouv function

The three phase inverter is proposed to control the active and reactive power flow from the renewable energy source to a three-phase generalized micro grid system. The proposed control system not only controls the grid power flow but also reduces the grid current total harmonic distortion in the presence of typical nonlinear loads. The control system shapes the grid current taking into account the grid voltage unbalance, harmonics as well as unbalance in line side inductors. The stability of the control system is ensured by the direct method of Lyapunov. SRC is also proposed to improve the performance of the current controller by estimating the periodic disturbances of the system. The proposed control system (implemented digitally) provides superior performance over the conventional multiple proportionalintegral and proportional-resonant control methods. A new inverter modelling technique is also presented to take care of unbalances both in grid voltages and line side inductors.