Realization of Large-Signal Stabilization for DC Microgrids via a Novel Decentralized Composite Control Approach

DC microgrids have draw extensive research attentions in recent decades. To ensure the stable operation of DC microgrids within a large stability margin when feeding largely variating loads, a novel decentralized composite control method is proposed in this paper. Firstly, the coupling interactions between dispatchable units (DUs)subsystems and uncertainties are estimated via a higher-order sliding mode observer. Secondly, a finite-time feedforward decoupling mechanism is introduced to counteract the interactions according to the obtained value. Hence, the realization of global large-signal stability can be ensured by designing a decentralized composite state feedback controller. With the proposed design strategy, the tradeoff between the completeness of the model and the complexity of large-signal analyses gets adequately addressed. Both dynamic property and stability margin can therefore be remarkably improved. The feasibility and superiority of the proposed strategy are verified by simulations in Matlab/Simulink.