Finite-Time Feedforward Decoupling and Precise Decentralized Control for DC Microgrids Towards Large-Signal Stability

This paper is initiated by considering an emerging practical issue that dc microgrids should be able to operate with a large-signal stability sense when feeding both resistive loads and constant power loads (CPLs). To be more specific, the stability should be ensured in the presence of large variations of integrated renewable sources and CPLs, system internal uncertainties, external disturbances, coupled interactions, and other adverse effects. From a control point of view, we intentionally propose a general solution to realize the exact decentralized tracking control task for interconnected systems. First, an alternative finite-time feedforward decoupling mechanism is presented, which is essentially different from existing design approaches via feedback domination or recursive cancellation processes. Second, a composite controller can be straightforwardly built from the system information since it is detached from stability analysis. One major advantage of the proposed design framework is that it reduces the design complexity and therefore facilitates the practical implementations. As a direct application, a simple decentralized composite controller is constructed for an autonomous dc microgrid system. Both numerical simulation and experimental comparison results show that a large-signal stability is achieved for dc microgrids under a range of different situations.