| 摘要 |
PURPOSE:To protect a GTO thyristor against an overcurrent by connecting a resistor to a capacitor provided at the output side of a power converter, and further connecting a diode in parallel with the resistor. CONSTITUTION:The main circuit of an AC/DC converter which uses a GTO thyristor is composed of a transformer T1, a bridge circuit B1 of a power converter, a capacitor C1, etc., and supplies power to a load circuit LO. Its controller has a comparator for comparing a command value VDS with a detected DC voltage value VD, and a proportional integrator PI, VCC, etc. Further, a resistor R1 and a diode D15 are connected between the circuit B1 and the capacitor C1. Thus, when GTO thyristors G11, G12 are simultaneously fired, for example, due to an erroneous firing, if the value of the resistor R1 is suitably selected, the current can be limited to the overcurrent withstanding resistance or lower of the GTO thyristor.
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