| 摘要 |
PURPOSE:To make unnecessary the synchronization among control devices in multiplying phase control by installing three phase control circuits and selecting the output from them which is sent out at the middle of the outputs in term of timing and making the output into ignition phase. CONSTITUTION:When striking pulse is given to each of thyristors that are connected to the 3-phase bridge of an electric power converting device, its multiplication phase control device is constituted with a selection circuit 13 that comprises three phase control circuits 12A-12C, flip-flop 15, 2-out-of-3 circuit 18 that consists of an AND circuit 15 and OR circuit 17 and an one-shot circuit 19. Accordingly, out of outputs of phase control circuits 12A-12C the one that is delivered in the middle of the duration is selected to be made the striking pulse, which makes unnecessary the synchronism among the phase control devices and at the same time, if one of the control devices are out of order there is no variation to the striking pulse and the operation can be continued. |
