Apparatus for controlling speed in induction motor

摘要

Provided is an apparatus for controlling speed in induction motor in which tension command and friction loss compensation are used to calculate a torque limit relative to an output of a speed controller, which is then used to limit the speed of the induction motor, whereby a tension sensor and a position sensor are not used in the continuous processing line to improve performance of the vector control type induction motor.

主权项

1. An apparatus for controlling speed in an induction motor driving a roller, the apparatus including a detector detecting a rotation speed of an induction motor, the apparatus comprising:
a first calculation unit configured to calculate a diameter of a material wound on the roller using the rotation speed, a minimum diameter of the material, a maximum speed of the induction motor and a line speed command; a second calculation unit configured to calculate a command speed using the diameter of the material, the line speed command, the minimum diameter of the material, and the maximum speed of the induction motor; a first adding unit configured to add a speed bias to the command speed to output a final command speed; a speed controller configured to generate a torque current command by compensating an error between the final command speed and the rotation speed; a third calculation unit configured to calculate a torque limit using the diameter of the material, a tension command, the minimum diameter of the material and friction loss compensation; and a limiter configured to limit the torque current command to a predetermined scope in response to the torque limit, wherein the third calculation unit calculates the torque limit by:torque⁢⁢limit⁢⁢tension⁢⁢command×current⁢⁢diameter⁡()minimum⁢⁢diameter⁡()⁢⁢friction⁢⁢loss⁢⁢compensation⁢ where the friction loss compensation is added in a winder mode of the roller, and the friction loss compensation is deducted in an un-winder mode of the roller.