Research on Filtering and Resonant Characteristics of LCL and LLCL Filters Based on Passive Damping

Abstract

The traditional L-type filter is widely replaced by LCL and LLCL type filters because of its high cost and poor filtering performance. In view of the excellent filter performance of the latter, this paper studies the performance of LCL and LLCL filters from the aspects of filtering performance and passive damping resonance suppression, and makes a comparative study. LCL and LLCL filters have different advantages and disadvantages in different harmonic bands. In this paper, four kinds of passive damping resonant suppression strategies are adopted. The theoretical and simulation experiments show that the four passive damping methods are effective .The resonant resistance of the device has played a suppression effect, in which putting the filter Capacitance and resistance in series and paralleling the network side inductance with resistance method are better, resonant suppression effect is outstanding. In this paper, through the design of specific parameters, experimental simulation, verify the correctness of the proposed conclusions.