| 摘要 |
PURPOSE:To protect a GTO thyristor from overvoltage damage at a fault by connecting a gate terminal of a semiconductor switch of the off-side circuit to a gate of an ON-gate current supplying capacitor via a clamp diode. CONSTITUTION:The positive terminal of the ON-gate current circuit capacitor 1 and a semiconductor switch 4 of the OFF side gate current circuit are connected via a clamp diode 8 flowing a current to the capacitor 1 only. Thus, when the semiconductor switch 4 interrupts the off-side current at the fault of the GTO thyristor, the interrupting current bipassed to the capacitor 1 via the diode 8. Thus, the voltage applied to the semiconductor switch 4 is clamped to a sum being a charging voltage of the capacitor 1 and a charging voltage of the capacitor 5 to protect the semiconductor switch 4 from an overvoltage. |
