Balancing control method of a microgrid with intermittent renewable energy generators and small battery storage

A cooperative control system for gas engine generators and a lead-acid battery in a microgrid was developed. The control system enables a microgrid system to balance the electric power demand and supply and to simultaneously control the state of charge (SOC) of the battery. To evaluate this control system, we simulated its performance in balancing the control of an experimental microgrid facility with two reciprocating engine generators for a day in which large fluctuation in PV and wind turbine output was observed. Based on the simulation, the rated power ratio of renewable energy installed in the microgrid can be increased beyond 50%, and simultaneously the minimum feasible capacity of the battery can be reduced to the capacity which is enough to charge the rated output of the intermittent renewable energy for 15 minutes.