| 摘要 |
PURPOSE:To suppress the occurrence of the higher-harmonic wave current when one of the multiple current interrupting means fails by making the operating phase difference between them equal with only the remaining current interrupting means and increasing the operating frequencies of the remaining current interrupting means. CONSTITUTION:A regenerative power absorbing device is constituted of an input capacitor 11 connected between a feeder line 4 and the ground and multiple serial circuits of resistors 21-24 and current interrupting means (choppers) 31-34 connected in series with this capacitor 11. Operating frequencies of the choppers 31-34 are staggered with each other by the preset value for operation, thereby the excessive power is absorbed by the resistors 31-34. In this case, the operating phase difference is set to 90 deg. when the choppers 31-34 are operating normally, but if one of the choppers fails, the phase difference between the remaining choppers is changed to 120 deg. to continue the operation. In addition, the remaining choppers are controlled to raise the operating frequencies.
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