Robust Model-Following Control for the Current Loop of a Medium Voltage Neutral Point Clamped Active Filter

This work presents a robust model-following control technique applied to the current loop of a three phase shunt active filter based on an NPC inverter. A modelling procedure for implementing the proposed control is also shown. The transfer functions for the control of the currents injected by the active filter in the synchronous dq frame have been derived. The proposed control technique is compared with conventional PI control, showing that the former improves the line current distortion without the need of a high crossover frequency of the current loop. The viability of the proposed scheme is shown by means of computer simulations using Saber™.