Active Filter Applying Discrete Tracking Control

Abstract

This paper presents a unique active filter system which operates with direct digital control (DDC). The system synthesizes the almost identical current with the total harmonic currents generated from the load. The current is injected to the a. c. source line by inverse phase. Although the control is based on simple digital calculations, it is proved that the a. c. source line current can be nearly sinusoidal current on a computer simulations as well as a bench mark test in a single phase circuit with nonlinear load.