In order to filter harmonics generated by the distributed system

comparing with L type filter and LC type filter

LCL type filter become one of the research hotspots in grid connected distributed generation system

because of its volume and cost advantages

and better inhibitory effect on high frequency harmonic. In this paper

by establishing the mathematical model of LCL type filter

its working principle and characteristics are analyzed in detail

and a set of practical design method of the parameters is put forward; and the resonant suppression methods of passive damping and active damping are discussed. Finally

through MATLAB / Simulink simulation software

the model is built

and the feasibility of the relevant theories and methods are verified.