| 摘要 |
PROBLEM TO BE SOLVED: To constitute an active filter for canceling high harmonics of a system, by a direct AC/DC conversion circuit without having an electrolytic capacitor. SOLUTION: The direct AC/DC conversion circuit 10, having bidirectional switches S1-S9, is connected in parallel with a thyristor bridge rectifier 20 which generates high harmonics. A current IAF, canceling the high harmonic components contained in the input current of the rectifier 20, is made to flow in the route, from an AC input terminal R, via the bidirectional switch S1 of an AC switch 81 of the phase, an output side reactor LUV, the bidirectional switch S4 of an AC switch 82 of the other phase to an AC input terminal S, by switching operation of the AC switches 81 and 82 of a plurality of phases, constituting the direct AC/DC conversion circuit 10. |
