An active filter for an unbalanced three-phase system using the synchronous detection method

This paper presents an active filter using the synchronous detection method. The equal-current synchronous detection method (CSD) is applied to calculate the reactive and harmonic current compensation components for triggering an active filter in an unbalanced three-phase power system. The experimental results of active filter operation using the synchronous detection method show that it is effective in eliminating line current harmonics and compensating the reactive current component. The merits of the proposed method are its capability to operate under an unbalanced three-phase system by per-phase calculation, to avoid conversion error by forced waveform calculation, to balance the unbalanced load and to accomplish a good performance with a very simple implementation.