High-Order Fully Actuated System Method-Based Control for DC Microgrids

The nonlinear dynamics introduced by boost converters and constant power loads (CPLs) pose significant challenges to microgrid (MG) controller design. To mitigate the detrimental effects of CPL on the stability of microgrid systems and the difficulties imposed on controller design, this study develops a high-order fully actuated (HOFA) model for nonlinear MGs with integrated CPL. The model can be used for the controller design of various types of nonlinear microgrids containing CPLs. In addition, an estimator-based fully actuated voltage controller is designed. The controller accommodates both buck and boost converters, as well as both modeled and unmodeled CPL scenarios, including abrupt load variations. By employing state transformation, dimensionality reduction, and order elevation techniques, the original under-actuated first-order CPL-integrated MG system is systematically transformed into a fully actuated high-order framework. Unlike traditional nonlinear control methods based on state space models, the control strategy derived from the HOFA model provides a simplified, implementable structure with parameterisable configurations. The effectiveness and applicability of the proposed nonlinear controller are validated on the MG hardware prototype platform with rich case studies.