| 摘要 |
PROBLEM TO BE SOLVED: To control an induction motor, in accordance with a desired torque command by providing a speed presuming device which presumes a rotation speed when the induction motor is rotating with a small flux vector in a speed- sensorless control device of the induction motor which is not equipped with a speed sensor. SOLUTION: This device is provided with a speed-presuming device 2, which presumes a rotation speed ω me of an induction motor by integrating with respect to time the vector product of the current vector i from a current detector 7 and the flux vector ϕ from a flux operation device 1, and a speed changing-over device 4, which outputs the rotation speed ω me from the speed- presuming device 2, if the flux vector ϕ is equal to a given value or lower and then selects and outputs the speed ω mc from a speed operation device 3, if the flux vector ϕ exceeds a given value. This structure enables the flux vector to be magnified by presuming the rotational speed of the induction motor, even if the calculated flux vector is small and thereby enables the control of motor through torque. |
