Active filter operation providing unity power factor supply system for drives and battery charging

The paper presents the concept of a parallel active filter which can compensate the nonactive power in the supply line and can also operate as a controlled DC source to supply an electric drive. Such a system provides sinusoidal shape of input current and operates with unity power factor. Simulation studies and laboratory tests have been carried out to study the performance of the filter in two cases. In the first case the filter compensates the nonactive power in the line without any DC load connected to the filter and in the second case a DC load is also linked to it. The control diagram of the system is proposed and tested. The filter uses an AC/DC converter with a diode bridge rectifier