Enhanced Nonlinear Passivity Based Control for Power Conversion System

This paper proposes an enhanced nonlinear passivity-based control (ePBC) for the power conversion system (PCS) to solve the lumped disturbances suppression problem, including external disturbances and internal disturbances consisting of system nonlinearities, model mismatches, coupling effects and so on. The PBC based on port-controlled Hamiltonian with dissipation (PCHD) model is designed for fast feedback tracking and stabilization of the nominal PCS. Then, the lumped disturbances are estimated by a nonlinear disturbance observer and compensated by feedforward term. Details on the design of baseline PBC, the nonlinear disturbance observer and stability robustness analysis are provided in this paper. With proposed method, a noticeable robustness against the lumped disturbances can be achieved as no more accurate system model is need for PBC method. The proposed method is implemented and validated through a down-scaled laboratory prototype. The simulation and experimental results are compared with the conventional PI and PBC methods, confirming that the proposed method can successfully achieve a good performance in zero steady-state tracking error, fast dynamic response and decoupling effectiveness against the lumped disturbances.