Shunt Active Power Filter with Selective Harmonics Compensation for LV distribution grid

A Shunt Active Power Filter (SAPF) employable in a Low Voltage distribution grid four-wires model is presented. The use of this device helps to improve Power Quality compensating harmonic currents, reactive power and current unbalances of a disturbing loads. Each compensating function can be activated or disabled according to the specific requirements of the application. A selective harmonic compensation is also possible, in order to avoid possible resonances at specific frequencies. A current hysteresis modulation with predictive calculation of threshold bands achieving fixed switching frequency is adopted for a fast dynamic response. The compensation performance of the proposed active power filter and the associate control scheme under steady state and transient conditions is demonstrated through digital simulations.