| 摘要 |
A DC power source is provided with a rectifier circuit connected to an AC power source and a smoothing circuit, which is comprised of a DC reactor and a parallel capacitor, connected to the output terminal of the rectifier. A load is connected to the parallel capacitor. A diode is connected in a closed circuit including the parallel capacitor and the load, with such a polarity as to check discharging current discharged from the parallel capacitor. The diode forms the closed circuit, together with an auxiliary power source for applying through a reactor to the diode a voltage to make the diode conductive in forward direction. In short-circuiting accident of the load, a conducting circuit established between the auxiliary power source and the diode is shut off to block an excessive current flowing through the diode into a short-circuiting path between the parallel capacitor and the load. |
