Vector controlling method and apparatus for induction motor

Claim 2

A vector controlling method for an induction motor having a rotator and stator, comprising the steps of: measuring an actual current flowing through said induction motor; calculating actual feedback currents and voltages i xs , i ys , V xs and V ys for said stator based upon said actual current measured; calculating variables α x and α y by using the equations α.sub.x =i.sup...sub.xs +a.sub.1 i.sub.xs -a.sub.0 V.sub.xs α.sub.y =i.sup...sub.ys +a.sub.1 i.sub.ys -a.sub.0 V.sub.ys estimating the magnetic flux φ.sup.. xr and φ.sup.. yr of said rotator by using the equations ##EQU18## and φ.sup...sub.xr φ.sub.xr +φ.sup...sub.yr φ.sub.yr =-a.sub.4 (φ.sub.xr.sup.2 +φ.sub.yr.sup.2)+a.sub.5 (φ.sub.xr i.sub.xs φ.sub.yr i.sub.ys); updating φ.sup.. r by using the equation ##EQU19## calculating the angular velocity of said rotator according to the equation ##EQU20## where P indicates a value of the number of phase divided by two; calculating a speed control input u 1 of said rotator and a magnetic flux control input u 2 of said rotator by using the equations ##EQU21## where k pj and k ij (for j=1, 2) are control gain values for the controller, and ω r * and φ r * are command inputs of ω r and φ r ; and substituting the values obtained in the preceding step into the equation ##EQU22## and thereby obtaining current commands i xs * and i ys *.

Claim 3

A vector controller for an induction motor having a rotator and stator, comprising: rectifying means for obtaining a direct-current voltage from an alternate voltage; speed controlling means for performing a control operation with a user's speed command ω r * and a speed feedback estimated value ω r , thereby outputting a control output value u 1 ; magnetic flux controlling means for performing a control operation with a user's magnetic flux command φ r * and a magnetic flux feedback estimated value φ r , thereby outputting a control output value u 2 ; non-interference controlling means for converting a nonlinear interference system into a linear non-interference system, by forming a nonlinear feedback and outputting stator current commands i xs * and i ys * on stator fixed coordinates; current controlling means for performing a proportional integration control with said current commands i xs * and i ys * and actual feedback currents i xs and i ys flowing through the induction motor, and converting the result into a voltage signal; first phase converting means for converting a two-phase voltage of said current controlling means into a three-phase voltage signal; switching means for driving the induction motor in response to said three-phase voltage signal output from said first phase converting means; second phase converting means for converting a three-phase current signal from the induction motor into a two-phase current signal; and calculating means for receiving the output signals of said current controlling means and said second phase converting means and calculating a rotator speed and rotator magnetic flux value for the induction motor control.

Claim 4

A vector controller for an induction motor having a rotator and stator, comprising: rectifying means for obtaining a direct-current voltage from an alternate voltage; speed controlling means for performing a control operation with a user's speed command ω r * and a speed feedback estimated value ω r , thereby outputting a control output value u 1 ; magnetic flux controlling means for performing a control operation with a user's magnetic flux command φ r * and a magnetic flux feedback estimated value φ r , thereby outputting a control output value u 2 ; non-interference controlling means for converting a nonlinear interference system into a linear non-interference system, by forming a nonlinear feedback and outputting stator current commands i xs * and i ys * on stator fixed coordinates; current controlling means for performing a proportional integration control with said current commands i xs * and i ys * and actual feedback currents i xs and i ys flowing through the induction motor, and converting the result into a voltage signal; first phase converting means for converting a two-phase voltage of said current controlling means into a three-phase voltage signal; switching means for driving the induction motor in response to said three-phase voltage signal output from said first phase converting means; second phase converting means for converting a three-phase current signal from the induction motor into a two-phase current signal; and calculating means for receiving the output signals of said current controlling means and said second phase converting means and calculating a rotator speed and rotator magnetic flux value for the induction motor control.

Claim 5

A vector controlling method for an induction motor having a rotator and stator, comprising the steps of: (a) measuring currents and voltages i xs , i ys , V xs and V ys for said stator and calculating stator variables α x and α y ; (b) calculating position angles cosθ r and sinθ r of the magnetic flux of said rotator and the magnitude φ r of the magnetic flux of said rotator, thereby estimating rotator magnetic fluxes φ xr and φ yr with respect to x-y coordinates; (c) calculating equations of the rotator magnetic fluxes φ xr and φ yr and stator currents i xs and i ys taking fixed coordinates as a reference axis, thereby calculating a rotator angular velocity Pω r ; (d) controlling an estimated speed value ω.sup.. r and estimated magnetic flux value φ.sup.. r in accordance with the calculation results of said rotator magnetic fluxes φ xr and φ yr and rotator angular velocity Pω r by using a speed command ω r * and magnetic flux command φ r *, thereby calculating a speed control value u 1 for said rotator and a magnetic flux control value u 2 for said rotator; and (e) operating said rotator magnetic fluxes φ xr and φ yr with respect to said speed control value u 1 and magnetic flux control value u 2 for said rotator, thereby obtaining stator current command values i xs * and i ys *.

Claim 6

A vector controlling method for an induction motor having a rotator and stator, comprising the steps of: (a) measuring currents and voltages i xs , i ys , V xs and V ys for said stator and calculating stator variables α x and α y ; (b) calculating position angles cosθ r and sinθ r of the magnetic flux of said rotator and the magnitude φ r of the magnetic flux of said rotator, thereby estimating rotator magnetic fluxes φ xr and φ yr with respect to x-y coordinates; (c) calculating equations of the rotator magnetic fluxes φ xr and φ yr and stator currents i xs and i ys taking fixed coordinates as a reference axis, thereby calculating a rotator angular velocity Pω r ; (d) controlling an estimated speed value ω.sup.. r and estimated magnetic flux value φ.sup.. r in accordance with the calculation results of said rotator magnetic fluxes φ xr and φ yr and rotator angular velocity Pω r by using a speed command ω r * and magnetic flux command φ r *, thereby calculating a speed control value u 1 for said rotator and a magnetic flux control value u 2 for said rotator; and (e) operating said rotator magnetic fluxes φ xr and φ yr with respect to said speed control value u 1 and magnetic flux control value u 2 for said rotator, thereby obtaining stator current command values i xs * and i ys *.

Claim 7

A vector controlling method for an induction motor as claimed in claim 3, wherein, in said (a) step, stator variables α x and α y are obtained by the equations α.sub.x =i.sup...sub.xs +a.sub.1 i.sub.xs -a.sub.0 V.sub.xs and α.sub.y =i.sup...sub.ys +a.sub.1 i.sub.ys -a.sub.0 V.sub.ys.

Claim 8

A vector controlling method for an induction motor as claimed in claim 3, wherein, in said (b) step, the equations for estimating φ xr and φ yr are ##EQU23##

Claim 9

A vector controlling method for an induction motor as claimed in claim 3, wherein, in said (c) step, the equation for obtaining said rotator angular velocity Pω r is ##EQU24## where P indicates a value of the number of phase divided by two.

Claim 10

A vector controlling method for an induction motor as claimed in claim 3, wherein, in said (d) step, the equations for calculating said speed control value u 1 and magnetic flux control value u 2 are ##EQU25## where k pj and k ij are control gain values for the controller, and ω r * and φ r * are command inputs of ω r and φ r .

Claim 11

A vector controlling method for an induction motor as claimed in claim 3, wherein, in said (e) step, the equation for obtaining stator current commands i xs * and i yr * is ##EQU26##