Comparative analysis of LCL-filter designs for paralleled inverters

This paper presents LCL-filter configurations for parallel connected grid inverters. Three different configurations can be used in an LCL-filter implementation. All of these can be dimensioned to produce the same harmonic attenuation. However, the filter resonance frequencies and how they vary with respect to the number of inverters differs between the configurations. This paper presents and analyses three filter configurations and a comparative study is made. All three configurations are designed to produce the same attenuation. The amount of filter components and their relative dimensions are compared and differences in the effectiveness of the passive damping are discussed.