基于模糊控制的并网逆变器的研究

Study of grid-connected inverter based on fuzzy control

并网逆变器采用LCL滤波器可有效滤除高次谐波,但LCL滤波器是无阻尼三阶系统,易发生谐振。采用无源阻尼方式来抑制谐振,并介绍了其原理及各参数的选取原则。采用并网电流与电容电流的双闭环控制策略,提出了以模糊PID双闭环控制技术控制并网电流,并进行了仿真研究。采用DSP作为控制芯片,设计了完整的主电路系统和驱动电路来进行实验验证。实验结果表明,该方法明显降低了并网电流的总谐波畸变率,避免了进网电流谐振,实现了进网电流的高功率因数。

Grid-connected inverter using LCL filter can eliminate high frequency hamonics effectively.Hovever,LCL filter is a third order system without damping and easy to resonate.This paper uses passive damping method to inhibit the resonance,and introduces the principle and the selection rule of filter parameters. In addition,it uses double-loop control strategy with the grid-connected current and capacitor current,proposes fuzzy PID double-loop control technology to control the grid-connected current,and makes a study of simulation. Using DSP as the control chip,it designs a complete main circuit and drive circuit to make experimental verification.The experimental results show that this method has significantly reduced the general harmonic distortion of grid-connected current,avoided the resonance of in-grid current and achieved high in-grid power factor.