Control of Three-Phase Shunt Active Power Filter Based on Five-Level NPC Inverter

The existence of harmonics within electrical power lines leads to higher power losses in distribution grids, interference issues within communication systems can occasionally lead to malfunctions in electronic equipment. Due to these problems, the issue of the quality of the power supplied to the final Consumer welfare is currently a matter of significant concern, more so than ever before. In this sense, the present work consists of the implementation and control of a parallel power active filter based on a multilevel converter of NPC type with vector pulse width modulation in order to neutralize the negative effects of harmonic currents resulting from non-linear load and the injection of additional reactive power into the electrical grid. The controller is designed using two nested loops. The internal current loop uses a non-linear control law integrating a PI compensator to ensure power factor correction. The external loop allows the DC bus voltage to be regulated to its set point to ensure the proper operation of the NPC multilevel converter. Numerical simulations in the MATLAB SimPowerSystems environment show that the system developed in this way effectively meets the objectives of improving power quality.