| 摘要 |
PURPOSE:To prevent the damage of an inverter by a method wherein the title device is provided with a means for detecting a current, which flows from a semiconductor breaker or a semiconductor switch to a load, and another means for detecting cross current between the semiconductor breaker and the semiconductor switch. CONSTITUTION:An AC current is generated by an inverter 4, inverting the output of a rectifier 2 or a battery 3, while power is supplied to the loads of respective systems through a thyristor breaker 5. As the preliminary means of an inverter circuit, the power is supplied to the loads through a thyristor switch 7 from a preliminary AC power source 6. The overcurrent OC1 of the loads is detected in a detector 9 by the output of a current transformer 8 for output current. A cross current OC2 between the thyristor breaker 5 and the thyristor switch 7 is detected in another detector 21 by the output of the current transformer 20 for the cross current. An interception selecting circuit 22 decides by the signals OC1, OC2 whether the overcurrent is on the side of a load or in the cross current and the thyristor breaker 5 or the thyrister switch 7 is put OFF by a switching control circuit 10. According to this method, power supply may be continued and the inverter 4 may be protected. |
