A control strategy for general-purpose active filters based on voltage detection

A new control strategy to realize general-purpose active filters based on voltage detection is proposed as an economical solution to harmonic compensation in distribution lines. The proposed control method is based on real-time digital simulation of an LC filter accomplished by a digital signal processor. The adaptive gain control to realize the automatic online adjustment of the compensating characteristics is introduced. This achieves the optimum operation according to the condition of the AC lines. Thus, the proposed active filter can be used as a general-purpose active filter. In this paper, the compensation characteristics of plural units of the proposed active filters connected to a distribution line are investigated. The theoretical investigation of the compensation characteristics is presented. Furthermore, to confirm the effectiveness of the proposed control strategy, some experimental results employing a test system are included