| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce surge voltage and noise even when a three-phase AC supply voltage is high in a power conversion apparatus. <P>SOLUTION: In the power conversion apparatus, the respective phase output terminals of a three-phase AC power supply 1 are connected with the respective phase input terminals of a three-phase rectifying circuit 3 through first reactors 2u, 2v, 2w. Also, a pair of capacitors 4a, 4b having the same capacity is connected in series between the output terminals of the three-phase rectifying circuit 3, and a load is connected in parallel with the series circuit of the pair of capacitors 4a, 4b. Further, switches 5u, 5v, 5w, which are operated by a controlling portion 7 a plurality of odd-number times in the half period of each power supply, are interposed connectively between the middle point of the pair of capacitors 4a, 4b and the respective phase input terminals of the three-phase rectifying circuit 3. Moreover, the switches 5u, 5v, 5w are so subjected to switching operations as to symmetrize the respective switching wave-shapes of the half period of the power supply by using the middle point between the first and last switching operations as a reference. Furthermore, step-down chopper circuits are so connected with the pair of respective capacitors 4a, 4b as to interpose connectively a capacitor 10f between the output terminals of the set-down chopper circuits. <P>COPYRIGHT: (C)2009,JPO&INPIT |
