A resilient bi‐level control strategy for power sharing and voltage balancing in bipolar DC microgrids

Abstract

Abstract In the three‐level DC‐DC converter‐based bipolar DC microgrids, accurate power sharing among distributed generators and voltage balancing between the positive and negative poles are two main control objectives. This article presents a resilient bi‐level control strategy which simultaneously satisfies both aforementioned objectives. The proposed control structure is a combination of a distributed consensus‐based cooperative method and a washout filter‐based method. In the first level, a distributed consensus‐based cooperative control method with considering time delays and communication noises is developed to realize proportional power sharing. At this level, DGs operate collaboratively using only neighbour‐to‐neighbour feedback over a sparse communication network, even if the communication network is susceptible to additive noise and time delay. In the second level, a decentralized control method is employed to restore the voltage of each pole of a bipolar DC microgrid to the desired value. The second level, which works without any communication links and additional control loops, utilizes a dynamic feedback incorporating washout filters. The whole proposed control strategy is robust against a single point of link‐failure and resilient against the communication time delays and noises as well. Comprehensive simulation studies are carried out in PLECS software to verify the effectiveness of the proposed control scheme.