A Three-Level Control Strategy for Battery Energy Storage System to Mitigate Power fluctuations and Compensate Reactive Power of Distributed Generators in a Microgrid

Abstract

The intermittent nature of produced power of renewable energy sources (RES) causes adverse impacts on the stability of system frequency and reduction of power quality at the point of common coupling (PCC). In this paper, a Battery Energy Storage System (BESS) is used to smooth the power fluctuations. The proposed control system consists of three control levels. The advantages of the control strategy are the battery life-cycle enhancement based on the variable time constant low-pass filter and two-stage battery protection through power smoothing while the voltage at the PCC is also kept stable. To validate the effectiveness of the control system a simulation study has been done in MATLAB/Simulink. The results confirm that the proposed control system reduces the RES output power fluctuations effectively and supports the voltage at PCC. Besides, the voltage oscillation at PCC is mitigated while protection of the battery from overcharge and over-discharge is also provided.