A reduction method of a DC capacitor in a single-phase active power filter

This paper deals with analysis and reduction of dc-voltage fluctuations in a single-phase active power filter caused by a sudden load change. The analysis reveals that the delay time of the harmonic detection causes dc-voltage fluctuations in transient states. A new control method is proposed to reduce the dc-voltage fluctuations, based on the analysis. As a result, the dc capacitor can be reduced to the required capacitance to satisfy the ripple current rating in steady states. Experimental results are shown to verify the viability of the analysis and the proposed control method.