Abstract:

For the LCL type filter, there is a natural resonance peak, and the change of the grid impedance in the actual power grid will further affect the stability of the rectifier. The Euler-Lagrangian mathematical model of LCL-type Vienna rectifier in dq synchronous rotating coordinate system was established, and the nonlinear hybrid passive control strategy of LCL-type Vienna rectifier under weak grid conditions was proposed, which theoretically guarantees the progressive of closed-loop system. It is stable and can meet the requirements of the dynamic and static characteristics of the rectifier and the harmonic suppression capability of the AC side under ideal grid and weak grid conditions. At the same time, it can eliminate the coupling term between dq axes in the established system model. In the Matlab/Simulink simulation environment, the feasibility of the proposed control strategy is verified by simulation experiments under ideal grid conditions and weak grid conditions.

Key words: Vienna rectifier, weak grid, LCL filter, decoupling, passivity-based control, robustness