An improved current control technique for the investigation of a power system with a shunt active filter

This paper initially refers to the devices used to compensate upper harmonics. Subsequently, it examines the principal methods for controlling an active filter which is connected to the electricity grid in order to compensate reactive power and to eliminate the electricity harmonics. The mathematic model following the p-q theory is analyzed for the creation of a reference current, aiming at the elimination of the upper harmonics and at reactive power compensation. An improved control method is presented regarding current control through the use of a Hysteresis Band with an altering tolerance band. In this way, current control is adjusted onto the load current.