Energy storage control for the Photovoltaic generation system in a micro-grid

Distributed generation (DG) that uses renewable energy sources has an unstable output and this can negatively affect existing electric power systems. In order to reduce above impact, we need to develop an energy control system to control the output through individual DG installed in a micro-grid. First, this paper designs a grid-connected Photovoltaic (PV) system and introduces the operation principle of the various parts as well with the control strategy of the power flow. The design of energy storage is of great significance as the output power of PV cells array is greatly affected by the light intensity and the temperature change. Then, it uses the battery as the energy storage device and designs the charge-discharge control strategy according to the characteristics of the battery. Finally it verifies the feasibility of the energy storage control strategy through the simulation models which is built based on the PSCAD/EMTDC platform.