Semi-Peer-to-Peer Safety Coordination Control for Distributed Battery Energy Storage System in DC Microgrids via Saturated Limitation

Abstract

This paper presents a semi-peer coordination control strategy to ensure the bus voltage stability and effectively constrain the power trajectory, thereby mitigating safety concerns arising from excessive unit power and communication failures in distributed battery energy storage systems (DBESS) based DC microgrids. Firstly, the primary controller is employed a saturated feedforward design to maintain bus voltage stability and address the excessive part of power allocation with droop control. The saturation results enable flexible switching of the reference state, allowing energy storage units (ESUs) to autonomously transition between voltage tracking and power tracking modes. Secondly, the dual-dynamic power allocation strategy is introduced with distributed consensus and saturation allocation.The power allocation with distributed consensus aims to achieve synchronous proportional charging and discharging for SOC balancing. For the offline ESUs of communication failures, saturation power allocation is designed with arrived operation point to avoid the over-utilization of offline ESUs. To address potential communication failures in offline ESUs, the saturation power allocation strategy based on the current operational point is devised to mitigate the risk of over-utilization of offline ESUs. Finally, simulations and experimental results verify the effectiveness of the proposed method.