Distributed Fixed-time Secondary Control for Heterogeneous Battery Energy Storage Systems

Based on the consensus theory of multi-agent systems (MAS), this article proposes a distributed fixed-time control strategy for heterogeneous battery energy storage systems (BESSs) in droop-controlled microgrids. The droop control of microgrids creates frequency deviations from the target value, leading to decreased accuracy of power sharing and frequency. A fixed time secondary control method is proposed to address the deviations arising from the primary control as well as to achieve the objectives of frequency regulation, active power sharing, and energy level balancing within a fixed timeframe. Additionally, the fixed-time control approach can provide an explicit estimate of the settling time without any dependence on the initial conditions. With the foundation of theoretical analyses, the consistency and convergence of the control algorithms are clearly revealed. Eventually, the suggested control strategy is validated by conducting case studies using a modified IEEE 34-bus testing system implemented in MATLAB.