A Control Method for Stable Operation of Distributed Generation Resources with Active Power Filter Capability

In this paper, a control scheme based on Lyapunov's stability theory is proposed for connection of distributed generation (DG) resources to electrical grids via power electronic converters. The dynamic analysis of the DG system is first carried out, and then the proper switching state functions of grid-interfacing converter are obtained for stable operation of DG unit. Unlike classical control techniques, the proposed method does not need proportional-integral (PI) regulators to control interfaced converter. By determining the suitable current references of the DG unit, the harmonic, reactive, and active currents of loads are fast provided. In consequence, grid currents will be linear and in phase with voltages of points of common coupling (PCC), when the maximum power transferred from DG resources to network is less than requested power of grid-connected loads. The simulation results validate the effectiveness of the proposed control method.