The Study Of Real-time Detecting Method For Harmonics And Reactive Currents

With the fast development of electric power technology, the various electric equipment are applied diffusely, and the harm caused by harmonious arouses people's attention. It becomes a pop problem that how to limit harmonics and compensate reactive currents. At present, it is an important tendency to limit harmonics by active power filter. The key technology of active power filter is real-time detecting harmonics and reactive currents, especially, accuracy and real-time ability of the test consequence are main influential factors of compensatory effect.In the paper, the method of separating active currents in single-phase circuit is studied deeply and a detecting method without phase-locked loop for harmonics and reactive currents in single-phase circuit is brought forward. Testified through analysis and simulation, this method is proved to detect harmonics and fundamental active and reactive currents well and truly. Compared with the method of separating active currents in single-phase circuit, under the condition of no increasing delay time, this method can avoid the effect of phase-locked loop and improve the detecting veracity.A detecting method without phase-locked loop for harmonics and reactive currents in three-phase circuit is put forward too in this paper. Testified through analysis and simulation, this method is proved that it can detect three-phase fundamental positive voltages,three-phase fundamental positive currents,three-phase fundamental positive active currents and other current heft to meet the need of compensation, whether electric voltage are symmetrical and aberrance, and it can be applied in three-phase three-wire circuit and in three-phase four-wire circuit.