| 摘要 |
PROBLEM TO BE SOLVED: To control opening and closing operations of a semiconductor breaker by measuring each of input side voltages and output side voltages of three phases and operating to instantaneously perform on-off operations of each bidirectional AC switch for each phase after a measured voltage is acquired.SOLUTION: With a control circuit under a closing state between a power supply unit and a load device during an opening/closing command signal ON, when voltages are measured the instant that voltages on input side and output side of three bidirectional AC switches meet simultaneously or at a time delay, the bidirectional AC switches of each phase are turned on, and values of electric currents running through the respective bidirectional AC switches are calculated. When comparison between the current value and a prescribed value indicates that the current value is in excess of the prescribed value, all the bidirectional AC switches are changed from an on state to an off state to form an opening state from a closing state.SELECTED DRAWING: Figure 1 |
