基于谐波频谱的LCL滤波器性能分析

摘要

为了减少逆变器中的谐波干扰,常采用LCL滤波器,该滤波器性能优良,被广泛采用,但目前LCL滤波器的电感电容仍然较大,系统成本仍较高,据此提出一种新型的设计方法,即通过逆变器输出的高次谐波峰值及其频谱,采用直线交截法依次获得谐振频率等相关滤波参数.与此同时,在此基础上对基于谐波频谱的LCL滤波器的各参数再次进行优化,然后通过与未经优化的LCL滤波器进行性能分析比较,从理论上揭示了该滤波器的优越性.最后通过在三相并网逆变器上进行实验验证,最终设计出了总电感电容较小,且满足并网要求的LCL滤波器.%In order to reduce the harmonic interference in inverter,LCL filter was adopted and popularized due to its per-fect performance,but at present,the inductance capacitance of the traditional LCL filter is still relatively large,so the system cost is high. In view of this,a new-type design procedure is proposed in this paper,with which high-order harmonic peak output by inverter and its spectrum are obtained,and resonant frequency and other related filtering parameters are got with the linear intercept method in proper order. On this basis,the various parameters of LCL filter are optimized again,and then the opti-mized filter is compared with unoptimized LCL filter to do further analysis. The superiority of the new-type filter was revealed. Af-ter experimental verification on three-phase grid-connected inverter,a new-type LCL filter that satisfied the requirements of LCL filter with small inductance capacitance was designed.