中文摘要：

在新能源分布式并网发电系统中，通常采用无源低通滤波器对脉宽调制逆变器产生的高频谐波进行有效衰减，而其滤波特性好坏直接决定着系统性能和成本体积。在分析现有L型、LCL型和LLCL型滤波器拓扑结构和滤波特性基础上，提出了一种新的LLCCL型并网接口滤波器。为抑制滤波器谐振尖峰以保证系统稳定运行，采用 Rd 阻尼法和Rd-Cd阻尼法对LCL型、LLCL型和LLCCL型滤波器进行无源阻尼，并对不同阻尼方法应用到不同滤波器拓扑时的谐振尖峰阻尼效果和高频谐波衰减效果进行了深入分析与对比研究。仿真和实验结果均验证了所提新型滤波器结构及无源阻尼技术的正确性和有效性。

英文摘要：

In distributed generation system based on renewable energy sources,a passive low-pass filter is normally used to attenuate high-frequency harmonic components generated by pulse width modulation based inverter. Therefore, the filtering characteristics of grid-interfacing filters have a significant influence on system performance, volume and cost. A new LLCCL filters is proposed based on the analysis of topologies and harmonic attenuation characteristics of L, LCL and LLCL filters in this paper. A series ofRd andRd-Cd damping method are comprehensively investigated and compared in terms of filter resonance suppressions and high-frequency harmonic mitigations for guaranteeing stable operation of LCL, LLCL and LLCCL type filters. Finally, simulation and experiment results are presented to demonstrate the correctness and effectiveness of the proposed LLCCL filter, as well as, of the developed passive damping methods （Rd or Rd-Cd damper） for the three filters.