| 摘要 |
PURPOSE:To enable detection of an accurate turn-off time without any error due to a commutation time by employing a detecting signal of a voltage across a reactor inserted in series with a thyristor element. CONSTITUTION:A DC output from a power rectifier circuit 2 is converted by a bridge having thyristors 3-6, and the converted output is supplied to a tank load circuit 13. On the other hand, saturable reactors 7-10 are connected in series with the thyristor. Then, the terminal voltage of one saturable reactor 9 is detected by a pulse transformer 18, and the detected voltage is applied to a waveform shaping circuit 19, and the terminal voltage of the load 13 is detected by the pulse transformer 16, and the detected voltage is inputted to a waveform shaping circuit 17. The outputs from the circuits 17, 19 and a signal having out of phase by 180 deg. from the thrystor gate signal from a gate signal forming circuit 15 are applied to the inputs of an NAND circuit 20. The period of the turn-off time can be obtained as an output from the NAND circuit 20. |
