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 on-line 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