| 摘要 |
PURPOSE:To enable to continue the operation stably even when a power source voltage drops due to instantaneous power interruption by controlling so that the DC voltage inputted to an inverter becomes substantially constant when the power source voltage drops due to the instantaneous power interruption. CONSTITUTION:A speed controller 12 outputs a torque current command in response to a deviation between a speed command N* and a speed detection signal N. A slip frequency detector 14 calculates a slip frequency command by a torque current command, the slip frequency command is added to a speed detection signal N, and applied to an oscillator 16. The detector 14 outputs the primary current command by the output of the oscillator 16, the torque current command and the exciting current command. When an instantaneous power interruption occurs, an instantaneous detector 27 is operated to switch a switching circuit 13. Thus, a voltage controller 25 outputs a torque current command in response to a deviation between the DC input voltage of the inverter 4 and the set value. |
