分布式发电并网无缝切换控制算法设计与实现

Design and Implementation of Grid-Connected Seamless Transfer Algorithm for Distributed Generation Systems

并网切换过程中冲击电流电压过大严重影响并网逆变器、大电网及本地负载的正常工作。为减小分布式发电并网过程对电网的冲击,提出了基于加权控制的三相逆变器并网无缝切换控制策略,解决了切换过程中存在不可控现象造成的电压电流冲击问题,给出了加权控制策略中参数的设计方法,探讨了加权系数对切换暂态的影响。该控制方法在不增加系统复杂度的前提下,实现了并网无缝切换。仿真和实验结果验证了该方法的正确性和可行性。

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.