초록 ▼

A three-phase-to-two-phase converter detects a torque current inside a motor as a DC quantity based on instantaneous values of motor currents. A slip frequency is estimated using the torque current, and the slip estimation is used to obtain a motor's revolutional speed. An error in revolutional spee

A three-phase-to-two-phase converter detects a torque current inside a motor as a DC quantity based on instantaneous values of motor currents. A slip frequency is estimated using the torque current, and the slip estimation is used to obtain a motor's revolutional speed. An error in revolutional speed estimation is compensated by a compensation value which is obtained by amplifying an excitation current common phase voltage command.

대표청구항 ▼

[ What is claimed is:] [1.] An induction motor control unit comprising:an input terminal of a revolutional speed command .omega.m*;an input terminal of a magnetic induction command .phi.*;a two-phase sinusoidal wave generator (22) wherein a motor current angular frequency .omega. is input and signal

[ What is claimed is:] [1.] An induction motor control unit comprising:an input terminal of a revolutional speed command .omega.m*;an input terminal of a magnetic induction command .phi.*;a two-phase sinusoidal wave generator (22) wherein a motor current angular frequency .omega. is input and signals of sin .omega.t and cos .omega.t are output therefrom;a three-phase-to-two-phase converter (16) into which the signals of sin .omega.t and cos .omega.t, and instantaneous values of motor currents iu, iv, and iw are input and from which an excitation current value id and a torque current value iq are output;a three-phase-to-two-phase converter (3) to which an excitation current common phase voltage command ed*, a torque current common phase voltage command eq*, and the signals of sin .omega.t and cos .omega.t are input and from which each phase voltage commands eu*, ev*, and ew* are output to the motor;a first subtracter (8) which subtracts the excitation current value id from an excitation current command id* based on the magnetic induction command .phi.*, and obtains an excitation current error;a first error amplifier (9) wherein an excitation current error is input, and the excitation current common phase voltage command is supplied therefrom to the motor;a second subtracter (1) which subtracts a revolutional speed estimation .omega.from the revolutional speed command .omega.m*, and outputs a revolutional speed error;a second error amplifier (2) wherein the revolutional speed error is input and a torque current command iq* is output therefrom;a third subtracter (5) which subtracts the torque current value iq from the torque current command iq* and supplies a torque current error;a third error amplifier (12) wherein the torque current error is input and the torque current common phase voltage command eq* is output therefrom to the motor;a fourth error amplifier (23) where the excitation current common phase voltage command ed* is input and a compensation value for revolutional speed estimation is output therefrom;a slip frequency estimater (6,7) wherein the torque current value iq is divided by the magnetic induction command .phi.*, and a slip frequency estimation .omega.s is output as a product of the immediately preceding division result and a coefficient equivalent to a secondary motor resistance r2; anda revolutional speed estimater (19,20) wherein the compensation value for the revolutional speed estimation is subtracted from the motor current angular frequency .omega., and the revolutional speed estimation .omega.s is output by a subtraction of the slip frequency estimation .omega.s from the result of the immediately preceding subtraction result.