一种LCL型并网逆变器双闭环参数设计方案

A double closed-loop parameter design scheme of LCL type grid-connected inverter

LCL滤波器是三阶系统,具有良好的高频谐波抑制能力,但LCL滤波器的谐振尖峰容易造成系统不稳定。为抑制LCL滤波器的谐振峰和电网高次谐波,通常采用双闭环控制策略。传统做法中单独设计内外环参数往往使得系统动静态特性偏执,造成系统性能下降。本文应用主导极点法零极点配置理论,采用根轨迹和频域分析法整定和优化LCL型双闭环控制器参数,结合根轨迹图中的闭环系统零极点得出控制器参数对系统稳态和动态特性的影响。该方法灵活方便,工程实用性强。可综合考虑系统性能指标对控制器参数进行优化。仿真实验结果表明,所寻求的参数优化方法具有良好的鲁棒性和动态特性,对电网高次谐波具有较强的抑制能力。

LCL filter has good ability of suppressing high frequency harmonics because it's a three-order system,but LCL filter has a resonant peak and makes the system unstable easily.To suppress resonance of LCL filter and harmonic in power system,the current double close loop is adopted as system's control algorithm.The systematic dynamic and static properties trend to paranoid because the outer-loop and inner-loop parameter are designed separately in traditional method.In this paper,the tuning controller parameters for LCL filter based on dominant pole placement and zeropole theory.To optimize the controller parameters,the frequency domain analytical method and root locus method are used to select the parameters.Finally,has analyzed the effect of controller parameters on system performances through root locus figure.This method is flexible and has comparatively strong practicality in engineering.The simulation and experimental results show that the method has excellent robust and dynamic quality.