| 摘要 |
PURPOSE: To control accurately the output torque of an induction motor, by controlling feedbackwise independently of each other the excitation current and torque current inside the motor for its excitation current command and torque current command, and by making the excitation inductance and secondary resistance of the parameters of the motor follow up. CONSTITUTION: An excitation current id and torque current iq in an induction motor are sensed respectively from instantaneous values iu, iv, iw of the actual currents of the motor by a means 9 for converting three-phase into two-phase. These currents id, iq are controlled feedbackwise independently of each other for an excitation current command id* converted from a magnetic flux density command ϕ* of the motor and for a torque current command iq* converted from a torque command T* of the motor. The error between iq* and iq is amplified by amplifiers 16, 21, and the output of the amplifier 21 is inputted to a data table(DT) 24 only in the case of the torque command T* being smaller than a predetermined value Trf which is determined by a comparator 22 and switch 23. The DT 24 integrates and holds the output of the amplifier 21 every magnetic flux density, using the value of the magnetic flux density command ϕ* as an address. Also, the output of the amplifier 16 is multiplied by a fixed gain Gr of an amplifier 25, and a factor r2 of a converter 8 is compensated according to the output of the amplifier 35. |
