| 摘要 |
PROBLEM TO BE SOLVED: To provide a noise reducer and a power converter which are miniaturized. SOLUTION: The noise reducer comprises: a zero-phase current detector 21 that is connected between an AC power supply 5 for feeding power and a power conversion circuit 3, and detects a leak current to an earthing line S2 generated by switching the power conversion circuit 3 as a noise current; and a noise reduction circuit 4 that feeds an inverted compensation current equal to the leak current to the earthing line S2 in which the leak current flows. The noise reduction circuit 4 comprises an amplification circuit 22 that amplifies the current detected by the zero-phase current detector 21 and forms the inverted compensation current equal to the leak current. The amplification circuit 22 comprises transistors Q11, Q12 and a capacitor C8. The compensation current fed from the noise reduction circuit 4 is set at the AC power supply 5 side apart from the zero-phase current detector 21. A core of the zero-phase current detector 21 has a cylindrical form, and each of an input winding and an output winding is of a one-turn penetration type. COPYRIGHT: (C)2005,JPO&NCIPI
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