Investigation of the possibility of removing the grid side inductance from the LLCL filter circuit

Abstract

It has been shown in the literature that in the grid connected converters, which uses trap based filters, like LLCL, the grid side inductance and therefore the filter size is effectively reduced. This paper with the goal of further reducing the filter size and cost, investigates the possibility of removing the grid side inductance of the LLCL filter considering a minimum value for the grid inductance. The proper range of other parameters of the LLCL filter is explored and a systematic design procedure for them is proposed, which ensures that the common practical filtering requirements are met. Simulation and experimental results confirm the effectiveness of the proposed filter design.