Real-time laboratory implementation results of an active filter

Proliferation of power electronics converters and electronic equipments has dramatically increased electric pollution in electrical distribution power systems. One solution to this problem could be the use of active filters that are capable of injecting distorted currents in order to cancel harmonics coming from non-linear loads for instance, or from any other equipment. Consequently, many theories have been developed to control active filters and then perform compensation of unwanted harmonics. In this paper, an overview of the instantaneous compensation theory is presented. This time domain approach was proposed by Akagi [1] under the name “p-q theory” or “instantaneous power theory”. It is the most widely spread theory for two or three phases and three or four wire systems. Then an appropriate control model for active filters based on the literature review is presented. That model is interfaced with real physical system owing to Opal-RT Software that definitely allows real-time control. Laboratory implementations are realized by using RT-Lab Simulator, and by interfacing it with a three phase 120/240 V system and a three phase non-linear load. The final system constitutes a Hardware in the loop (HIL) application. Real-time tests on an Opal-RT simulator, are shown and commented in the paper.