| 摘要 |
PURPOSE:To prevent the damage of a thyristor converter due to the malfunction of a switching element by connecting the primary side of a pulse transformer in series with the switching element and connecting a light emitting element which transmits a gate signal to the secondary side of the transformer. CONSTITUTION:When a switching element 5 is shortcircuited of malfunctioned in a period of t=t1-t2 or a control circuit for the switching element 5 is malfunctioned so that a base current flows continuously, a gate trigger electric signal iLED does not become OFF at t=t2, and continues until t=t2, but it is attenuated by the saturating characteristics of the pulse transformer 8, and the signal becomes 0 at t=t2''. Accordingly, a gate trigger light signal is not generated at t=t4- t5, thereby preventing the damage of the thyristor converter. |
