| 摘要 |
PROBLEM TO BE SOLVED: To provide a fault detection circuit that detects a fault even when a thyristor is short-circuited while holding a certain amount of impedance, in a thyristor series circuit in which a plurality of thyristors are connected in series.SOLUTION: A gate control device 2 detects a fault of a thyristor in a thyristor series circuit in which thyristors TH1-THN are connected in series. The device includes voltage detectors DV1-DVN for detecting each forward-voltage signal FV1-FVN of the thyristors TH1-THN. Three voltage detectors DV1-DV3 of the voltage detectors DV1-DVN detect reverse-voltage signals RV1-RV3, respectively, and determine a failure of the thyristor from which a forward-voltage signal is detected when the forward-voltage signals FV1-FVN are detected in a period when the reverse-voltage signals RV1-RV3 are detected. |
