弱电网条件下LCL型Vienna整流器控制策略研究

Control Strategy of Vienna Rectifier With LCL Filter Under Weak Grid Conditions

针对LCL型滤波器存在固有谐振尖峰,实际电网存在变化的电网阻抗以及电网电压背景谐波的问题,基于dq同步旋转坐标系,提出弱电网条件下LCL型Vienna整流器非线性混合无源控制策略,该控制策略可保证闭环系统的渐进稳定,在理想电网和弱电网条件下均实现直流侧电压快速跟踪给定值及交流侧电流正弦化,同时能够实现所建立的系统模型中dq分量之间耦合项的消除。应用Matlab/Simulink搭建了系统仿真模块,并在理想电网条件和弱电网条件2种情况下进行了仿真试验,仿真试验验证了所提控制策略的可行性。

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.