Distributed Hybrid-Triggered Observer-Based Secondary Control of Multi-Bus DC Microgrids Over Directed Networks

The secondary control (SC) of DC Microgrids (MGs) exhibits fast control dynamics as a consequence of low system inertia, leading to substantial communication, networked sensor sampling, and computational load. The existing pure event-triggered (ETed) or self-triggered (STed) SC approaches for DC MGs struggle to optimize communication, sampling, and computation efficiency concurrently. To address this issue, this study introduces a novel distributed hybrid-triggered (HTed) dynamic-consensus-observer-based SC tailored for average voltage restoration and load current sharing in general multi-bus DC MGs over directed networks. Firstly, the dynamic model of SC over directed networks is established. Subsequently, a Lyapunov stability condition is derived to guarantee the stability of the proposed HTed SC. The HTed SC integrates ETed communication with STed sampling and computation, eliminating the need for continuous networked sensor sampling and trigger condition monitoring present in traditional ETed SCs while also reducing the trigger conservativeness of conventional STed SCs. Consequently, the HTed SC achieves a lower communication, sampling, and computation rate. Experimental tests conducted using an MG prototype and a real communication network validated the efficacy of the proposed methodology.