| 摘要 |
PURPOSE:To reduce higher harmonics which current to electric source, by making a plurality number of rectifiers to include rectifying unit of controlable and nocontrolable type in the rectifiers, and selecting this operation sequence, when above- mentioned a plurality number of rectifiers which include a plurality number of rectifying units are made to be operated in parallel. CONSTITUTION:Rectifying units T11 and T22 in each rectifier C1, C2 are made to be controllable type which includes thyristors, and at the same time, residual rectifying units are made to be noncontrollable type which is composed of diode bridge, and switch S is provided at the alternating current side. Also, T11 is put at first step from bottom in the rectifier C1 and T22 is put at second step from bottom in the rectifier C2. And, these are orderly and selectively operated such that controlled angle of T11, T22 is controlled at first from maximum phase to minimum phase, then the switch S is made and T211, T322 are made to be conductive. Therefore, since primary current wave shapes of transformers A1, A2 are not lapped, higher harmonics which are currented to electric source can be made to be small. |
