| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a speed control method for an induction motor that does not cause the shortage of torque even in a zero-speed range without receiving an influence of a speed estimation error due to a change or the like in motor constant. <P>SOLUTION: When a speed command value or a speed estimation value is less than or equal to a prescribed value, the speed control method of the induction motor uses the speed command value for operating a frequency command value instead of the speed estimation value. Also, when the speed command value or the speed estimation value is less than or equal to the prescribed value, the method controls a slide frequency estimation value of the motor operated based on the output value of the current control unit, and an output frequency of a power transformer corresponding to the additional value of the speed command value. <P>COPYRIGHT: (C)2004,JPO |
