A digital adaptive filter for detecting harmonic, active and reactive currents

Abstract

There have been a number of harmonic and reactive current-detecting methods for active power filters. All of these methods suffer from limitations such as being computationally costly or being sensitive to environmental changes. In this study, a computationally simple digital adaptive detecting filter that is insensitive to environmental changes is proposed. First, some digital and analogue adaptive methods developed recently are reviewed, comparing their abilities. Second, a digital adaptive filter is proposed that overcomes the limitations of the previous methods. Third, the transfer function of the filter is obtained, and its validity is illustrated via computer simulations. Finally, the feasibility of the filter is also demonstrated in the time domain. The simplicity of the proposed approach makes it suitable for real-time applications by using a digital signal processor or a mixed-signal microcontroller.