Research on Passivity Based Control and Active Disturbance Rejection Control for MMC-UPQC

摘要

In this paper, the port controlled hamiltonian with dissipation (PCHD) model of unified power quality controller based on modular multilevel converter (MMC-UPQC) under dq0 frame of reference is established. Based on the model and passivity of MMC-UPQC, the passivity based controller is designed by injecting virtual damping in current inner loop, which can accelerate the convergence of error storage function and ensure the global stability of MMC-UPQC. To improve the disturbance rejection ability, the nonlinear active disturbance rejection control (ADRC) is employed in voltage outer loop to provide desired current for inner loop. A circulating current controller based on ADRC is designed, which can effectively reduce switching losses. Compared with PI control, the proposed control has advantages such as good dynamic and static performance and strong disturbance rejection ability. The simulation results of five-level MMC-UPQC in Matlab/simulink validate the feasibility of the proposed control strategy.