Circuit breaker using semiconductor

A solid-state circuit breaker disposed between a power system and a load, comprising a current sensor for detecting current flowing from the power system to the load, and configured to perform a circuit breaker operation based on detection results of the current sensor, the solid-state circuit breaker comprising:

• a cut-off switch physically connecting or disconnecting the solid-state circuit breaker to or from the power system;
• a semiconductor switch unit comprising a first semiconductor switch having a drain terminal connected to the power system, a second semiconductor switch having a drain terminal connected to the load, and first and second diodes having anodes and cathodes respectively connected to source terminals and drain terminals of the respective semiconductor switches;
• a bypass electric circuit connecting the drain terminal of the first semiconductor switch and the source terminal of the second semiconductor switch;
• and
• a control unit that closes the bypass electric circuit to supply a current of the power system to the load through the bypass electric circuit and the second diode while the first and second semiconductor switches are turned off when the power system and the solid-state circuit breaker are connected through the cut-off switch, wherein a turn-off state of the semiconductor switch is a state in which no voltage is applied to a gate terminal or a voltage lower than a preset threshold voltage is applied to the gate terminal, and turns on, when a preset condition is satisfied, the first and second semiconductor switches to form a first electric circuit through which the power system and the load are connected by way of the semiconductor switch unit, and opens the bypass electric circuit to supply the current of the power system to the load through the first electric circuit,
• wherein the control unit determines that the preset condition is satisfied when a current level between the power system and the load is restored to a rated current level as a result of a measurement by the current sensor.