| 摘要 |
DC power supplies (10a, 10b) are electrically connected to smoothing capacitors (Ca, Cb) by way of first and second relays (12a, 12b), respectively. A current limiting circuit (13) is connected to in parallel to the first relay (12a), but not provided for the second relay (12b). At the startup of a power supply system (5), the smoothing capacitor (Ca) is precharged with a current passing through a current limiting resistor (15) with the first and second relays (12a, 12b) turned off and a third relay (14) turned on. After the completion of precharge of the smoothing capacitor (Ca), the smoothing capacitor (Cb) is precharged with a current from the DC power supply (10a) accompanied by periodic on/off control of switching elements (S1-S4) with the first relay (12a) turned on and the second relay (12b) and the third relay (14) turned off. |
