| 摘要 |
PURPOSE:To prevent the field distortion due to DC of a reactor by providing an ignition phase lag angle limiting means to limit the minimum value of the ignition phase lag angle of a thyristor to a prescribed value. CONSTITUTION:The minimum values of the ignition lag angle of the thyristors 15,16 are limited to 30 degrees, and the ignition lag angle never becomes smaller than it. Thus, in the case of the occurrence of voltage fluctuation, the ignition width of the thyristor 16 is prevented from becoming larger than 180 degrees, and the field distortion due to DC of the reactor 14 can be prevented. On the other hand, when the minimum value of the ignition lag angle is controlled so as to be 30 degrees, since the peak value of a current to flow in the reactor 14 is limited to 40%, the reactance of the reactor 14 is set at 40% of that of a traditional device. Accordingly, the reactive power compensating capacity equal to that of the conventional device can be provided to this device. |
