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US 5,196,778 AGranted
Control apparatus suitable for use in induction motor
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorTakahiro Hayashida
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AssigneeMitsubishi Denki Kabushiki Kaisha
InventorTakahiro Hayashida
Estimating the term…
A gain change-over switch according to the present invention serves to change over at least one of a current loop gain and a velocity loop gain to a value of the gain greater than that in other modes, in the case where a rotational-position control mode is selected as a control mode of the induction motor out of a rotational-speed control mode and a rotational-position control mode or where the rotational-position control mode is chosen and at the same time, a work mode for driving a work piece to work the same is selected, whereby an induction motor is controlled with high accuracy. Further, an exciting change-over switch according to the present invention serves to select a reinforcement exciting circuit for producing the secondary flux in the induction motor, which is greater than that produced by a weakening variable exciting circuit, only in the case where the rotational-position control mode and in the work mode are selected, thereby to control the induction motor with high accuracy. In other modes, the change-over switch serves to select the weakening variable exciting circuit for variably controlling the excitation-component of the primary current to produce the secondary flux corresponding to a torque component developed by the primary current.
A control apparatus suitable for use in an induction motor in a machine tool drive, which includes a current loop for performing feedback control of the primary current of the induction motor, a velocity loop for performing feedback control of the rotational speed of said induction motor and a position loop for performing a feedback control of the rotational position of said induction motor, said apparatus being adapted to select either one of a rotational-speed control mode and a rotational-position control mode and being adapted to control said primary current of said induction motor in accordance with said selected mode of either said rotational-speed control mode or said rotational-position control mode, said control apparatus comprising:
A control apparatus suitable for use in an induction motor in a machine tool drive, which includes a weakening variable exciting means for variably controlling an excitation-component of the primary current in said induction motor so as to produce the secondary flux corresponding to the torque component developed by the primary current, in accordance with either one of rotational-speed control mode and a rotational-position control mode, said control apparatus comprising:
Dependencies are inferred from the claim text.