Power Tracking and State-of-Energy Balancing of an Energy Storage System by Distributed Control

This paper addresses the power control problem for an energy storage system consisting of multiple energy storage units with dual objectives. On one hand, the power output of the energy storage system should track its reference. On the other hand, the state-of-energy of all the energy storage units should be balanced so as to maintain the maximum power capacity of the energy storage system. To achieve these two control objectives simultaneously, a novel distributed control scheme is proposed, which has three features. First, the proposed control scheme is distributed, which enables a more flexible and scalable configuration of the communication network. Second, the proposed control scheme allows online switch-on and switch-off operations for energy storage units, which makes the energy storage system more efficient for preplanned check and more resilient to unexpected fault. Third, the state-of-energy balancing mechanism can ensure the maximum power capacity of the energy storage system. Comprehensive numerical case studies are provided to show the effectiveness of the proposed control scheme.