Averaging Control of the DC-Link Voltage in Shunt Active Filters

In this paper, an averaging control strategy is proposed for the DC link voltage dynamics of shunt active filters (SAF), which are used in three-phases current harmonic compensation. The SAF considered are based on AC/DC three-phase boost converter topology. Power losses due to parasitic resistances cause the instability of the voltage dynamics. The robust solution for perfect harmonics compensation, presented by Marconi et la. (2004) is used, while the dead zone voltage controller from these previous works is replaced by a new one that directly stabilizes the average value of the voltage, allowing for the necessary voltage oscillations during operation, and improving the voltage dynamics behavior. The average component is calculated directly from measurement of the actual voltage, using the so-called phasors method. A standard PI controller, which is designed in the frame of averaged values, is used for stabilization. Some additional work is required to obtain the actual control input based on the averaged values delivered by the controller