刘毓梅,赵巧娥,高戈,章伟明.弱电网下LCLCL型并联逆变器并网系统的电流优化控制[J].电测与仪表,2019,56(24):122-127. liuyumei,zhaoqiaoe,gaoge,zhangweiming.Optimal control of grid-connected current in grid-connected system of LCLCL parallel inverter under weak grid[J].Electrical Measurement & Instrumentation,2019,56(24):122-127.
弱电网下LCLCL型并联逆变器并网系统的电流优化控制
Optimal control of grid-connected current in grid-connected system of LCLCL parallel inverter under weak grid
Aiming at the shortcoming of traditional LCL filter, this paper uses LCLCL type filter based on proportional feedback of capacitive current to realize the notch action of harmonic at switching frequency on the premise of retaining the high frequency harmonic attenuation ability of LCL filter. Secondly, the Norton equivalent model of two parallel inverter grid-connected systems under weak grid is established, and the coupling effect of grid impedance between inverter and grid is analyzed. An extra positive feedback loop of grid-connected current will be introduced into the feedforward control of power grid voltage considering the impedance of the power system, which can reduce the phase margin of the system. By using the resonant feedforward control, the feedforward control and grid-connected current control can be decoupled at the middle and high frequency of the fundamental frequency, the stability of the system can be improved and the quality of the grid-connected current can be optimized. Finally, the feasibility and effectiveness of the proposed strategy are verified by simulation analysis in MATLAB/Simulink.
