A Fully Distributed Fixed-Time Secondary Controller for DC Microgrids

DC microgrids (MGs) have gained significant attention for its remarkable advantages of integrating renewable energy sources and electronic loads. In order to improve the operational performance of the dc MG in both steady and transient states, a fully distributed fixed-time-based secondary controller is proposed to remove the dc voltage deviation and provide proportional current sharing simultaneously. The secondary control of each distributed generation (DG) consists of a fixed-time consensus-based current and voltage regulators that use relative information from the neighboring DGs through a sparse communication network. In contrast to the existing controllers, the proposed controller is distinguished with its accelerated convergence time, which does not rely on the initial values. Besides, the stability of the proposed method is verified through the Lyapunov function. A simulation model is built in PLECS to prove the effectiveness of the proposed control strategy. Some scenarios are introduced to validate the link-failure resiliency, plug-and-play capability, the scalability, and the feasibility under various time delays. Meanwhile, a dc MG experimental prototype is built to verify the controller performance.