并网型LCL滤波器中阻尼电阻的分析及设计

摘要

传统的无阻尼LCL型滤波器存在一个零阻抗谐振点,而电流型逆变器的输出含有较多的高次谐波,如果逆变器直接带无阻尼LCL滤波器并网势必给电网带来一定的谐波污染,同时也会影响无差拍电流跟踪的精度.在无阻尼的LCL型滤波器基础之上,设计了带阻尼的滤波器；并且利用仿真软件分析了阻尼电阻值对系统损耗和滤波效果的影响.对样机输出电流进行傅里叶分析可知阻尼型滤波器能够显著的减少输出电流谐波,同时提高无差拍的跟踪精度.%The traditional LCL filter without resistor has a resonance oscillation, and the output of current-mode inverter contain high order harmonics, Directed connect with grid will bring harmonic pollution to grid and be harmful to the precision. In order to solve this problem, a kind of filter with resistor is designed, and the math model of filter is established to analysis the effect of resistance value on the filter result, system stability and efficiency. Through the analysis, a conclusion prove that the filte can reduce the THD of current .improve the tracing accuracy.