| 摘要 |
PURPOSE:To prevent regenerative stall regardless of the magnitude of the quantity of regeneration by increasing the speed of response of regenerative control operation by detecting regenerative currents. CONSTITUTION:When the number of revolutions of an induction motor 4 is decreased suddenly, large regenerative voltage is generated, and large regenerative currents flow through a resistor R by the regenerative voltage. Voltage generated at both ends of the resistor R is detected by a regenerative current detector 8, the detecting output is output to a control circuit 6 through an OR gate 10, and a driver circuit 5 is controlled so that the regenerative voltage of the induction motor 4 is lowered. That is, the increase of regenerative voltage is detected by the regenerative current detector 8 at the time faster than a regenerative voltage detector 7, thus preventing the stall of the regenerative control of the induction motor 4. |
