| 摘要 |
PURPOSE:To prevent the delay in the protecting operation of a gate turn-OFF thyristor (GTO) by providing an AND circuit for inhibiting an OFF gate signal to the GTO. CONSTITUTION:When GTO thyristors 6a, 6b are simultaneously fired, a shortcircuit current flows from a power source 1, and a current simultaneously flows through current detectors 10a, 10b, thereby facilitating the simultaneous firing of the thyristors 6a, 6b of respective upper and lower arms 12a, 12b. Since the arms 12a, 12b are not absolutely simultaneously fired at the normal control time, the protection can be effectively performed. Accordingly, when its state is detected to inhibit the OFF gate signals of the GTO thyristors 6a, 6b, the thyristors can be protected without time delay. |
