THREE-PHASE AC-DC CONVERTER FOR SUPPRESSING INPUT- CURRENT HARMONICS AND IMPROVING POWER FACTOR

摘要

PROBLEM TO BE SOLVED: To convert a power, to suppress harmonics of each input current of a power source and to improve the power factor to 0.98 or larger at a single section of an AC-DC conversion, in an AC-DC converter that inputs a three- phase AC and outputs a single-phase DC.;SOLUTION: In the converter that converts a three-phase AC to a single-phase DC, bridge diodes BD1, BD2 and BD3 are respectively connected to input filters IF1, IF2 and IF3 at each phase, outputs of the filters are respectively connected to each primary side of transformers T1, T2 and T3 of each phase, having switching elements Q1, Q2 and Q3 that are connected to each phase, and then rectifying by current resonance is conducted. The converter is also characterized with the power of a full-wave rectifier output having a different phase by each 120° angle is synthesized by a resonance capacitor C1 of the secondary side of the transformer T1, T2 and T3, and a smoothing circuit that consists of a smoothing choke coil L and a smoothing capacitor CI is connected to the output side to convert AC-DC, to control the harmonics and to improve the power factor.;COPYRIGHT: (C)2002,JPO