Distributed Accurate Current Sharing for Multi-Bus DC Microgrids With Minimizing Voltage Regulation Deviations: A Game-Theoretic Approach

Current sharing and voltage regulation in multi-bus DC microgrids are two fundamental control objectives, between which there is a tradeoff due to their conflicting nature. Different from the existing literature, this paper focuses on distributed accurate proportional current sharing with the minimization of voltage regulation deviations in multi-bus DC microgrids. First, a novel game-theoretic framework is established, where each bus node in the DC microgrid acts as a player and the problem of proportional current sharing and voltage regulation can be reformulated as a Nash equilibrium seeking problem. Then, based on the formulated game, a new regularization-based distributed least-norm Nash equilibrium seeking strategy is proposed, which incorporates a gradient-based algorithm, a leader-following consensus algorithm and a dynamic average consensus algorithm. It is demonstrated that the proposed strategy can ensure accurate proportional current sharing while minimizing the deviations of all bus voltage regulation. In the end, the efficacy of the proposed strategy is validated through several case studies on a six-bus DC microgrid system, in terms of performance evaluation, robustness to load variations and communication failures, and plug-and-play ability.