Power control in isolated Microgrids with renewable distributed energy sources and battey banks

This paper presents a new strategy to control the power generation from existing energy sources in autonomous and isolated Microgrids. In this study, the Microgrid is composed of a power electronic converter, supplied by a battery bank, which is used to form the AC network (grid-forming power converter), an energy source based on a wind turbine and its respective power electronic converter (grid supplier converter), and the loads. The primary subject of the proposed control strategy is to keep the energy balance into the Microgrid, in order to control the battery bank state of charge even when more power can be generated than loads can consume. This goal is achieved controlling the generated power into the Microgrid, without using dump load or any physical communication with the power electronic converters or individual energy source controls. The electrical frequency of the Microgrid is used for dictating the amount of power the energy sources need to generate in order to maintain the battery-bank state of charge below its maximum permissible value. A modified droop control to implement this work is proposed.