A novel design method of LCL filter for a grid-interconnected three-level voltage source inverter

In this paper, Firstly, maximum of ripple current is given through analysis of the current transient process. The principle of LCL filter is analyzed, and it is proved that the inductance of LCL filter is equal to one third of that of L filter in the situation of the same effect. According to power condition and ripple rejection, inductance of L filter is determined, so as to inductance of LCL filter. While satisfying the filter effect, converter current harmonic is reduced as low as possible to determine inductance ratio and capacitance. The simulation and experiment testify this design scheme is feasible.