| 摘要 |
PURPOSE:To largely reduce the reactive power consumed by an AC/DC converter and to suppress the variation in the voltage of a system by falling the set current value to the prescribed value under the condition that a controlled delay angle becomes nearly 90 deg. or that the DC voltage is lowered. CONSTITUTION:When a DC wire line is grounded by fault, an AC/DC converter is abruptly transferred to a zero power factor operation. That is, the output of a controlling voltage selecting circuit 10 becomes a value corresponding to a controlled delay angle 90 deg.. When the condition that the controlled delay angle becomes nearly 90 deg. is detected by a level detecting circuit 13 which is thus operated, a switch 14 is opened OFF. In this manner, the set current value to be inputted to a current control circuit 8 becomes a value determined by a lower limiter circuit 15. That is, the DC current is abruptly decreased. |
