Privacy-Preserving Sliding Mode consensus for Distributed DC Microgrid Systems with Fault Estimation: an Output Mask Approach

Information leakage and voltage balance issues among subsystems introduce additional uncertainties to the stable operation of distributed DC microgrids. Although effective algorithms for voltage balance exist, comprehensive solutions addressing the aforementioned disturbances are scarce due to privacy protection constraints. To meet these challenges, this paper proposes a privacy-preserving sliding mode control (SMC) method for distributed DC microgrids. First, a mathematical model of a DC microgrid with an energy storage source is established and transformed into a mathematical multi-agent system (MAS) model. Additionally, an output mask privacy-preserving method is employed by introducing an output mask function to obscure system state information while ensuring the protected information converges accurately to the reference value. Subsequently, to enhance the convergence performance of the masked system, a SMC approach based on variable structure is employed. Considering the nonlinearity introduced by the mask function, the traditional SMC is improved and extended to accommodate multi-agent masked systems, enabling the design of more effective sliding mode controllers. Moreover, actuator faults leading to measurement errors are accounted for in the design of the sliding mode controller, enhancing the fault-tolerant capability of the system. The proposed coordinated control scheme not only achieves fast convergence and voltage consistency but also ensures privacy protection for exchanged information. Additionally, the scheme exhibits fault tolerance. Finally, simulation results validate the feasibility of the proposed approach.