عنوان مقاله [English]
In recent years, active filters have been considered and developed for elimation of harmonics in power networks. Comparing with passive, they are smaller and have better compensating characteristics and resistance to line distortions. In this paper, a novel idea based on adaptive filter theory in presented to develop an active filter to eliminate the distortions of an arbitrary signal. Using this idea, new methods of active power filters, are introduced to remove harmonic distortions in single phase power networks. Stability of these methods are analyzed and the simulation results are shown. Design and implementation of this adaptive active filter are done and the performance and advantages of this technique are affirmed by the practical results. Exact estimation of amplitude, frequency and phase of input signal first harmonic is the most important advantage of this adaptive technique. Furthermore, this method is for canceling the harmonic of any arbitrary signal and can easily be modified for other systems, and three phase networks. Due to its adaptive nature, this technique can adopt itself with variation in environment and system parameters and be adjusted for optimal behaviour. Keywords: Adaptive active filter, ac network, amplitude, Phase and frequency Estimation, Floque theorem, Averaging theorem.