The Research on Seamless Switching Control Strategy for Micro-grid Integrating Photovoltaic and Energy Storage

A large number of distributed photovoltaic power generations that are connected to the distribution network will have a serious impact on the power quality of the distribution network and load power security. Integrating energy storage and photovoltaic cells into the micro-grid can effectively improve the power quality of distribution network and the reliability of load consumption. This paper is a research on the seamless switching control strategy for micro-grid integrating photovoltaic and energy storage (MIPES). Firstly, it analyzes the boundary conditions of MIPES seamless switching control of grid-connected/islanded modes and studies the output characteristics of photovoltaic cells over a day. The DC bus voltage can be stabilized within a certain range to meet the requirements for MIPES seamless switching of grid-connected/islanded mode. Secondly, this paper analyzes the working characteristics of silicon controlled rectifier (SCR). The results show that when SCR is turned off naturally, the load voltage will rise sharply, affecting the safety of local load. Therefore, a control strategy for SCR switch forced shutdown is proposed to solve the problem of sharp rise of load voltage during grid-connected/islanded conversion of MIPES and to ensure the load security. Finally, relevant simulation studies are carried out to verify the rationality and effectiveness of the proposed control technology.