A proportional resonant controller tuning method for grid connected power converters with LCL+trap filter

Three-phase power converters are largely employed in power generation facilities based on renewable energy sources, and these converters commonly working in grid connection mode are frequently connected to the grid through passive filters. Nowadays the need for larger power converter-based generation plants increases continuously, and LCL+trap filter arises as a solution when switching frequency is reduced due to the power increase. However, the tuning of current controllers becomes more complex as the LCL+trap filter lead to a considerably high order system. In this work a method for tuning the gains of proportional resonant current controllers for three-phase high power converters linked to the grid through a LCL+trap filter is proposed and analyzed. Simulation and experimental results taken in different cases are shown to validate the proposed method.