| 摘要 |
PROBLEM TO BE SOLVED: To need no large-sized reactor and accomplish the improvement of input power factor and suppression of harmonic current. SOLUTION: The input terminals in respective phases of a three-phase rectification circuit 3 are connected with the respective phases of a three-phase alternating-current power supply 1 through first reactors 2u, 2v, and 2w. A pair of capacitors 4a and 4b, equal to each other in capacitance, are connected in series between the output terminals of the three-phase rectification circuit 3. A load is connected in parallel with a series circuit of a pair of the capacitors 4a and 4b, and switches 5u, 5v, and 5w are connected between the midpoint between a pair of the capacitors 4a and 4b and the input terminals in respective phases of the three-phase rectification circuit 3. Each of the switches 5u, 5v, and 5w is made to operate by the odd number of a plurality of times in the half cycle of the power supply. Further, each of the switches 5u, 5v, and 5w is made to perform switching operation so that the switching waveform thereof in the half cycle of the power supply is symmetric with respect to the midpoint between the first switching operation and the last switching operation. COPYRIGHT: (C)2003,JPO
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