Control of Current-Source Active Power Filter using Unit Vector Template in Three Phase Four Wire Unbalnced System

In recent years there has been considerable interest in the development and application of active power filters using current source active power filters for harmonic filtering. The unbalanced load resulting zero sequence current can affect the performance of shunt active filter adversely. In this paper a novel active, filter control for a three-phase four-wire unbalance system has been designed. This method allows the calculation of the reference current under non-sinusoidal and unbalanced three- phase supply voltage conditions. The proposed filter is based on Akagi´s instantaneous power theory (IPT), which are organized in different independent blocks. We introduce a unit vector template to derive fundamental voltage signal from an unbalanced source. The reference currents are then compared with actual source current in a hystersis band controller. Extensive simulation results obtained using MATLAB/SIMULINK under R-L non-linear loading conditions are presented and discussed.