| 摘要 |
PROBLEM TO BE SOLVED: To reduce a harmonic current, and to improve an input power factor using a simple circuit configuration in a three-phase DC power supply and a compressor drive device that uses the DC power supply. SOLUTION: The DC power supply comprises a three-phase AC power supply 1, reactors 2u, 2v, 2w, a bridge rectifying circuit 3, an electrolytic capacitor 4, a load 5, bidirectional switches 6u, 6v, 6w, capacitors 7u, 7v, 7w, a zero-cross detection means 8 for detecting the zero-crossing of a supply voltage, and a bidirectional switch control means 9. The compressor drive uses the DC power supply. In this case, the bidirectional switches 6u, 6v, 6w are turned on and off for each half cycle of each phase voltage in the three-phase AC power supply 1 for alternately repeating the charge and discharge of the capacitors 7u, 7v, 7w via AC reactors 2u, 2v, 2w, thus decreasing the harmonic current and improving the input power factor. COPYRIGHT: (C)2006,JPO&NCIPI
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