Decentralized Adaptive Energy-Shaping for Integrated Voltage Regulation With Large-Signal Stability in DC Microgrids

Maintaining bus voltage stability is a central challenge in dc microgrids (MGs). This article introduces a decentralized adaptive energy-shaping approach (DEC) that seamlessly merges constant voltage and droop mode (DM) controls, ensuring the comprehensive large-signal stability of the MG. Central to the DEC’s architecture is its stratification of the MG into autonomous distributed unit (DU) subsystems. Using a nonlinear observer, this strategy effectively recognizes the electrical interactions among individual DU subsystems, obviating auxiliary output current sensors. This structured approach breaks down the intricate stability challenges of the MG into more manageable sections. These sections are carefully designed to address estimated couplings and reinforce each DU subsystem’s resilience. The introduced stabilization method, inspired by the passivity-based port-controlled Hamiltonian (pcH) system theory, adopts a passive control damping mechanism coupled with a dynamically adjusted interconnection coefficient. This ensures a smooth stability of DU subsystems, even when faced with significant disturbances. Rigorous theoretical analyses, underpinned by the Lyapunov theorem, corroborate the systemic stability conferred by the DEC design. Furthermore, it demonstrates robustness against unforeseen input voltage variations. Simulations and experiments demonstrate that the proposed control approach accelerates system recovery and broadens the stability margin.