Blockchain Protocol-Based Secondary Predictive Secure Control for Voltage Restoration and Current Sharing of DC Microgrids

DC microgrids with distributed architectures inevitably encounter the threats of communication constraints and cyber attacks, and there is little research to address these two communication irregularities simultaneously. To provide DC microgrids with maximum resistance to communication constraints and cyber attacks, a distributed predictive secure control method based on blockchain protocol is proposed in this paper. The proposed control approach is the first attempt to address cyber attacks with a hybrid of data and models, improving the resilience and robustness of DC microgrids. With the help of practical Byzantine ideas, the proposed strategy preserves the resilience strengths of the blockchain against corruption and discards its shortcomings of low real-time performance, significantly enhancing the security without compromising the dynamic performance of the system by active intervention. Subsequently, a bound on the communication delay induced by the blockchain network under the expected security index is given based on the theoretical analysis. Unlike the existing practice of passively tolerating communication delays and packet dropouts, the predictive control method proposed in this paper actively compensates for them experienced by DC microgrids. Then, an analytical model of the closed-loop DC microgrid system is developed, and stability analysis is presented accordingly. Finally, several experimental tests performed on a PV-based DC microgrid hardware system are presented to demonstrate the effectiveness of the proposed control strategy.