An Active and Reactive Power Controller for Battery Energy Storage System in Microgrids

Battery energy storage systems (BESS) are widely used for renewable energy applications, especially in stabilizing the power system with ancillary services. The objective of this paper is to propose an active and reactive power controller for a BESS in microgrids. The proposed controller can operate the BESS with active and reactive power conditions and realize power smoothing and voltage regulation. The demanded active power flow generated through a low pass filter (LPF) is used to control the power smoothing for microgrids. LPF design is presented based on the BESS sizing and genetic algorithm (GA). The demanded reactive power flow generated according to the reactive current calculation is used to compensate the microgrid voltage to fulfill the voltage regulation. The analysis of the vector diagram is adopted to validate the proposed controller and to explain the applicability and functionality of the voltage regulation for microgrids. To verify the validity of the proposed controller, a 1-kW grid-connected inverter is built to demonstrate the ability of power smoothing and voltage regulation. Both simulations and hardware experimental results agree well with the theoretical analysis.