PROBLEM TO BE SOLVED: To suppress influence to the main apparatus of an inverter to a minimum and to suppress higher harmonics, by branch-connecting a circuit composed of a first AC reactor, a second rectifier circuit, a second DC smoothing capacitor, and a high-speed switching means connected in reverse parallel with the second rectifier circuit, to a three-phase AC power source side. SOLUTION: To a three-phase AC power source 1 side, a first alternating current 3 and a second DC smoothing capacitor 33 are connected, and a higher harmonic suppressing circuit B is formed. This higher harmonic suppressing circuit B performs control by a second control means 13. Besides, a second rectifier circuit 26 and a high-speed switching means 27 are connected in reverse parallel. To the main apparatus A of an inverter on a more three-phase AC power source 1 side than the first rectifier circuit, the higher harmonic suppressing circuit B is branch-connected in parallel, in this way. Consequently, higher harmonic suppressing measures for a power source is taken by the use of the higher harmonic suppressing circuit B connected in parallel to the main apparatus A of an inverter. Accordingly, it becomes possible to reduce the capacity of the main apparatus A of the inverter.
展开▼
