Analysis and implementation of a three-phase voltage-doubler soft-switching active power filter

The system analysis and circuit implementation of a three-phase voltage-doubler soft-switching active power filter (VDSSAPF) comprising four main switches and four auxiliary switches is proposed in this paper. All main switches in the proposed VDSSAPF 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. Moreover, the proposed VDSSAPF can compensate the current harmonics, improve the power factor and balance the unbalanced load. Additionally, the dedicated control circuit required for soft-switching active power filter operation is implemented using a FPGA circuit, reducing overall system cost and complexity. Finally, some experimental results for a 500 W prototype are presented to verify the theoretical analysis and system performance.