Design and implementation of grid-connected seamless transfer algorithm for distributed generation systems

The impulse current and voltage have impact the normal operating of Grid, inverter and load. To mitigate the impact on power grid and load during the mode-switching of grid-connected distributed generation (DG) system, this paper presents a voltage weighted control seamless transfer algorithm for a utility interactive three-phase inverter with grid-tied modes of operation. The paper analyzes the reasons of transient impact in detailed; there is an uncontrollable intermediate state in the transfer process of grid-connected, which will cause voltage and current overshoot. The effects of parameters weighted on transient are discussed. The algorithm can ensure that the transient transfer is seamless transfer without increasing system complexity. Simulation and experiment results verify the correctness and feasibility of the proposed method.