| 摘要 |
PURPOSE:To control a motor stably upon droppage of source voltage by operating a slip frequency based on a torque current command value or a detected torque current value corresponding to whether the source voltage is normal or dropped. CONSTITUTION:When a comparator 17 detects that a DC intermediate circuit voltage VDC is higher than a set value, a torque current command value I is fed to a slip frequency operating unit 28 through a signal switcher 30. It the DC intermediate circuit voltage VDC is lower than the set value, a detected torque current value IT is fed through the signal switcher 30 to the slip frequency operating unit 28 based on a signal fed from the comparator 17. The slip frequency operating unit 28 operates a slip frequency based on a secondary flux command value PSI* and the torque current command value IT or the detected value IT and outputs the operated slip frequency omegaS. |
