A passivity based nonlinear controller for hybrid DC microgrid with constant power loads

This study examines the voltage stability challenge in hybrid DC microgrids that power Constant Power Loads (CPLs). Due to uncertainties in both supply and demand, traditional linear controllers are often inadequate, leading to inevitable voltage oscillations under uncertain conditions. This article introduces a robust passivity-based control (PBC) approach aimed at reducing instability issues, while considering the dynamic behaviour of the hybrid DC microgrid in the presence of CPL. The main objective is to achieve large-signal stabilization of the output voltage of a CPL powered by a hybrid DC microgrid through a series-damped passivity-based control (PBC) scheme, while considering the dynamic performance of renewable energy sources and loads. DC microgrids, which include parallel source subsystems, present additional challenges in analysing the nonlinear stability of the entire system, often requiring complex dynamical equations. Therefore, the stability analysis, based on the passivity property, can be easily conducted for each subsystem individually within the hybrid DC microgrid. The proposed controller prevails over other non-linear controllers because of its accuracy, reliability, and simplicity, while also exhibiting a more robust response compared to the control techniques previously suggested. MATLAB simulations and experimental results are provided to validate the robustness of the proposed controller.