A novel three-phase voltage-doubler soft-switching active filter

A novel three-phase voltage-doubler soft-switching active filter (VDSSAF) comprising four main switches and four auxiliary switches is proposed in this paper. All main switches in the proposed VBSSAF operate at zero-voltage-switching (ZVS) turn on, while the auxiliary switches operate at zero-current-switching (ZCS) turn off. The reduction in the number of switches can also increase the reliability, since the control circuits are thereby reduced to two sets. The proposed VBSSAF can compensate the current harmonics, improve the power factor and balance the unbalanced nonlinear load. Moreover, a critical value of the capacitor voltage magnitude on the DC side and a critical value of the reactor inductance on the AC side for successful harmonic current tracking are also derived for design applications. Some experimental results of the VBSSAF, rated 400 W and operated at 40 kHz, are provided to demonstrate the performance.