Improving the Efficiency of the Shunt Active Power Filter Acting with the Use of the Hysteresis Current Control Technique

Abstract

Calculation of the reference waveform for the compensating current generated by the shunt active power filter (ShAPF) can be carried out using various methods. In this article, this calculation is performed indirectly on the basis of tracking and processing of the ShAPF DC-link capacitor voltage. At the same time, the energy stored in this capacitor is used to generate the compensating current. Therefore, the operation of this capacitor during compensation, i.e., changes in energy stored in it and the voltage waveform on its terminals, is characteristic and crucial for the method considered. Once the current reference waveform is determined, it can be generated by ShAPF in various ways, but always using the energy stored in the DC-link capacitor. The power module of the active filter uses transistor switches to realize the required compensating current. During their operation, power losses occur that can be divided into either switching or conduction. The article shows that, in the case of the indirect control method and the hysteresis current control technique used, it is possible to reduce the operating frequency of the switches and the load on the DC-link capacitor. Thanks to this, it is possible to reduce power losses in these elements and extend their lifetime.