| 摘要 |
PURPOSE:To make the rotation of a motor smooth by stabilizing the control in ultra-low speed region or low speed region. CONSTITUTION:A monitoring circuit 11 checks an estimated speed value LAMBDAomegaR' from a speed estimating/operating section 7 to decide whether it is lower than a preset lower limit. If a decision is made that the estimated speed value LAMBDAomegaR' is lower than the lower limit set value, a switch 12 is turned oppositely to the direction shown on the drawing. The switch 12 is inserted into an estimated speed supply path and when the switch 12 is turned, an estimated speed value LAMBDAomegar generated from a function generator 13 is fed to an adder 9 where it is added to a slip frequency omegas to produce an output frequency omega1 which is then fed to a voltage type vector operating section 1. |
