Design of LCL Filter For Grid Connected Three Phase Three Level Inverter to Meet IEEE 519 Standards

The design of an LCL filter for a 12 kW three-phase three-level NPC inverter for 400 line-line RMS voltage on-grid connected application is presented in this paper. Harmonics are the main issues for the grid, LCL filter has good capability to compensate harmonics and improve the output. This paper discusses the switching scheme used in this design as well as the LCL filter's bode diagram both with and without damping resistor. The design of this LCL filter has been validated via simulation and it is concluded that resulted output waveforms are meeting the IEEE 519 standards for both current and voltage harmonic distortion limits. Input dc voltages ranging from 600 V to 960 V are applied to the digital setup and it is found that IEEE 519 harmonic distortion limits are meeting for this voltage ranges.