Design of passive trap-LCL filters for two-level grid connected converters

This paper proposes a passive filter design method and validation analysis based on a Trap-LCL filter topology for implementation in grid connected two-level converters for high power applications. The proposed topology appears as an alternative to the conventional LCL filter, since reduced filter parameters can be obtained while still ensuring high filtering capability for switching frequency harmonics. Furthermore, a step-by-step filter design method will be introduced in order to provide a clear scope on the tuning procedure, as well as on the main requirements that the filter should satisfy. Finally, a comparative study between a conventional LCL and a LCL-Trap filter will be performed in simulation with the goal of finding a meaningful evaluation of the advantages and disadvantages provided from the LCL-Trap configuration.