| 摘要 |
PURPOSE:To suppress transient fluctuation of inverter output voltage, when power supply is switched from a commercial power source to an inverter, by gradually transferring power supply from the commercial power source to the inverter then disconnecting the commercial power source. CONSTITUTION:When a switch 8b is turned ON while a switch 8a is turned OFF, a voltage command operating unit 13 produces a voltage command VINV shown by formula I. Consequently, the voltage at point A is equalized to V0. Even if the switch 8a is thrown in, current flows scarcely because the voltages at the opposite ends of the switch 8a are equal. Then the output voltage command VINV of the inverter is gradually brought to a level shown by formula II with the switches 8a, 8b being turned ON. Current flowing through the switch 8b decreases gradually as VINV transfers from the value shown by formula I to the value shown by formula II, and thereby the output current I0 is entirely fed from the inverter through an AC filter reactor 10 and the switch 8a. Thereafter, the switch 8b is turned OFF. |
