Voltage source active filter with small inductors and improved efficiency

Power losses and voltage stresses are a problem in active filters. This paper proposes a voltage-source active filter (VSAF) with an LCLC-circuit which has lower voltage stresses, smaller power losses and smaller inductors than a conventional VSAF. The method is based on the series capacitor structure used to block the fundamental supply voltage component. The structure improves the efficiency of the active harmonic filtering and saves energy. Experimental results are presented in the paper. The results show that the power losses decreased significantly and very small inductors could also be used.