SFX algorithm based adaptive control of active filters without detecting current harmonics

This paper proposes a new current control method for active power filters (AF´s). It requires only detecting the source current. It requires neither detecting AF output current nor extracting a harmonic component from the source current. Thus, the current control system can be greatly simplified compared to conventional load current detection AF´s. This paper introduces an adaptive digital filter (ADF) with a synchronized filtered-x (SFX) algorithm. An SFX-ADF based current controller exhibits a high gain only at fundamental and harmonic frequencies that the load current contains. A proportional regulator is also used to improve the dynamic performance of the current control system. Simulation and experimental results demonstrate that the proposed AF can exhibit excellent filtering performance.