The comparison research of DC side and AC side parallel active power filter for three-phase rectifier

Three-phase dc side and ac side parallel active power filters are both suitable for harmonic current suppression for three-phase uncontrolled rectifiers. The two kinds of filters are compared from the three aspects including of harmonic compensation performance, compensation capacity and switch stress. The results indicate that the harmonic suppression performances of dc side active power filter are better than the ac side one, because the dc side active power filter is paralleled in the dc side of the rectifier, so the current changing rate of dc side active power filter is smaller than the changing rate of the ac side one. Because of the dc side active power filter just operating at two quadrants of voltage and current, so the compensation capacity and switch stress are smaller than the ac side one.