Induction motor drive and a parameter estimation method thereof

Claim 2

A control system performing a vector control of an induction motor using a speed sensor, comprising: a first reference point setting unit setting a point P R at an arbitrary position on a stator current vector plane; a first vector transforming unit transforming a measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; a magnitude calculating unit obtaining difference between magnitudes of the vectors transformed by said first vector transforming unit for the measured and observed values; a phase difference calculating unit obtaining a difference between phases of the vectors transformed by said first vector transforming unit for the measured and observed values; a first rotor resistance estimating unit estimating a rotor resistance of the induction motor from the difference between magnitudes; and a stator resistance estimating unit estimating a stator resistance of the induction motor from the difference between phases.

Claim 3

The control system according to claim 1 , wherein: the first rotor resistance estimating unit estimates the rotor resistance of the induction motor according to an equation: R′r=(k PRr +s·k IRr )·(|i s −P R /−/i′ s− P R /) Wherein: R′r—an estimated value of the rotor resistance; i s —the measured value of the stator current; i′ s —the observed value; s—a Laplace operator; k Irr and k PRr —gains.

Claim 4

The control system according to claim 1 wherein said first reference point setting unit sets the point P R at a position inside a vector locus of the stator current: on the stator current vector plane.

Claim 5

The control system according to claim 1 , wherein the stator resistance estimating unit estimates the stator resistance according to an equation R′s=(k PRs +s·k IRs )·(/i s −P R /−/i′ s −P R /) Wherein: R′s—an estimated value of the stator resistance; i s —the measured value of the stator current; i′ s —the observed value; s—a Laplace operator; k IRs and k PRs —gains.

Claim 6

A control system performing a vector control of an induction motor using no speed sensor, comprising: a first reference point setting unit setting a point P R at an arbitrary position on a stator current vector plane; a first vector transforming unit transforming measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; a phase difference calculating unit obtaining a difference between phases of the vectors transformed by said first vector transforming unit for the measured and observed values; and a stator resistance estimating unit estimating a stator resistance of the induction motor from the difference between phases.

Claim 7

A control system performing a vector control of an induction motor using no speed sensor, comprising: a first reference point setting unit setting a point P R at an arbitrary position on a stator current vector plane; a first vector transforming unit transforming measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; a phase difference calculating unit obtaining a difference between phases of the vectors transformed by said first vector transforming unit for the measured and observed values; and a stator resistance estimating unit estimating a stator resistance of the induction motor from the difference between phases.

Claim 8

The control system according to claim 5 , wherein said first reference point setting unit sets the point P R at a position inside a vector locus of the stator current on the stator current vector plane.

Claim 9

The control system according to claim 5 , wherein the stator resistance estimating unit estimates the stator resistance according to an equation R′s=(k PRs +s·k IRs )·(i s −P R )·(i′ s −P R ) Wherein: R′s—estimated value of the stator resistance; i s —the measured value of the stator current; i′ s —the observed value; s—a Laplace operator; k IRs and k PRs —gains.

Claim 10

A control system performing a vector control of an induction motor, comprising: a harmonic signal injecting unit injecting a harmonic signal in a flux current; a second reference point setting unit setting a point P Rr at an arbitrary position on a stator current vector plane; a second vector transforming unit transforming harmonic components, corresponding to the harmonic signal, of measured and observed values of a stator current of the induction motor into vectors starting from the point P Rr on the stator current vector plane; a magnitude calculating unit obtaining a difference between magnitudes of the vectors transformed by said second vector transforming unit for the harmonic components of the measured and observed values; and a second rotor resistance estimating unit estimating a rotor resistance of the induction motor from the difference between magnitudes.

Claim 11

A control system performing a vector control of an induction motor, comprising: a harmonic signal injecting unit injecting a harmonic signal in a flux current; a second reference point setting unit setting a point P Rr at an arbitrary position on a stator current vector plane; a second vector transforming unit transforming harmonic components, corresponding to the harmonic signal, of measured and observed values of a stator current of the induction motor into vectors starting from the point P Rr on the stator current vector plane; a magnitude calculating unit obtaining a difference between magnitudes of the vectors transformed by said second vector transforming unit for the harmonic components of the measured and observed values; and a second rotor resistance estimating unit estimating a rotor resistance of the induction motor from the difference between magnitudes.

Claim 12

The control system according to claim 8 , wherein said second reference point setting unit sets the point P Rr on a straight line obtained from current values corresponding to resistance values which are larger and smaller than a nominal rotor resistance value on the stator current vector plane.

Claim 13

The control system of according to claim 8 , wherein the second rotor resistance estimating unit estimates the rotor resistance of the induction motor according to an equation R′r=(k PRr +s·k IRr )·(/i d *−P Rr /−/i′ d *−P Rr /) Wherein R′r—an estimated value of the rotor resistance; i d *—the measured harmonic component of the stator current; i′ d *—the harmonic component of the observed value; s—a Laplace operator; k IRr and k PRr —gains.

Claim 14

The control system according to claim 8 , further comprising: a first reference point setting unit setting a point P R at an arbitrary position on a stator current vector plane; a first vector transforming unit transforming measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; a phase difference calculating unit obtaining a difference between phases of the vectors transformed by said first vector transforming unit for the measured and observed values; and a stator resistance estimating unit estimating a stator resistance of the induction motor from the difference between phases.

Claim 15

The control system according to claim 11 , wherein said first reference point setting unit sets the point P R at a position inside a vector locus of the stator current on the stator current vector plane.

Claim 16

The control system according to claim 11 , wherein the stator resistance estimating unit estimates the stator resistance according to an equation R′s=(k PRs +s·k IRs )·(i s −P R )·(i′ s −P R ) Wherein: R′s—an estimated value of the stator resistance; i s —the measured value of the stator current; i′ s —the observed value; s—a Laplace operator; k IRs and k PRs —gains.

Claim 17

A control system performing a vector control of an induction motor using a speed sensor, comprising: first reference point setting means for setting a point P R at an arbitrary position on a stator current vector plane; first vector transforming means for transforming measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; magnitude calculating means for obtaining a difference between magnitudes of the vectors transformed by said first vector transforming unit for the measured and observed values; phase difference calculating means for obtaining a difference between phases of the vectors transformed by said first vector transforming means for the measured and observed values; first rotor resistance estimating means for estimating a rotor resistance of the induction motor from the difference between magnitudes; and stator resistance estimating means for estimating a stator resistance of the induction motor from the difference between phases.

Claim 18

A control system performing a vector control of an induction motor using a speed sensor, comprising: first reference point setting means for setting a point P R at an arbitrary position on a stator current vector plane; first vector transforming means for transforming measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; magnitude calculating means for obtaining a difference between magnitudes of the vectors transformed by said first vector transforming unit for the measured and observed values; phase difference calculating means for obtaining a difference between phases of the vectors transformed by said first vector transforming means for the measured and observed values; first rotor resistance estimating means for estimating a rotor resistance of the induction motor from the difference between magnitudes; and stator resistance estimating means for estimating a stator resistance of the induction motor from the difference between phases.

Claim 19

A control system performing a vector control of an induction motor using no speed sensor, comprising: first reference point setting means for setting a point P R at an arbitrary position on a stator current vector plane; first vector transforming means for transforming measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; phase difference calculating means for obtaining a difference between phases of the vectors transformed by said first vector transforming means for the measured and the observed values; and stator resistance estimating means for estimating a stator resistance of the induction motor from the difference between phases.

Claim 20

A control system performing a vector control of an induction motor using no speed sensor, comprising: first reference point setting means for setting a point P R at an arbitrary position on a stator current vector plane; first vector transforming means for transforming measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; phase difference calculating means for obtaining a difference between phases of the vectors transformed by said first vector transforming means for the measured and the observed values; and stator resistance estimating means for estimating a stator resistance of the induction motor from the difference between phases.

Claim 21

A control system performing a vector control of an induction motor, comprising: harmonic signal injecting means for injecting a harmonic signal in a flux current; second reference point setting means for setting a point P Rr at an arbitrary position on a stator current vector plane; second vector transforming means for transforming harmonic components, corresponding to the harmonic signal of a measured and observed values of a stator current of the induction motor into vectors starting from the point P Rr on the stator current vector plane; magnitude calculating means for obtaining a difference between magnitudes of the vectors transformed by said second vector transforming means for harmonic components of the measured and observed values; and second rotor resistance estimating means for estimating a rotor resistance of the induction motor from the difference between magnitudes.

Claim 22

A control system performing a vector control of an induction motor, comprising: harmonic signal injecting means for injecting a harmonic signal in a flux current; second reference point setting means for setting a point P Rr at an arbitrary position on a stator current vector plane; second vector transforming means for transforming harmonic components, corresponding to the harmonic signal of a measured and observed values of a stator current of the induction motor into vectors starting from the point P Rr on the stator current vector plane; magnitude calculating means for obtaining a difference between magnitudes of the vectors transformed by said second vector transforming means for harmonic components of the measured and observed values; and second rotor resistance estimating means for estimating a rotor resistance of the induction motor from the difference between magnitudes.

Claim 23

A parameter estimation method of an induction motor, comprising: setting a point P R at an arbitrary position on a stator current vector plane; transforming measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; obtaining a difference between phases of the vectors for the measured and the observed values; and estimating a rotor resistance of the induction motor from the difference between magnitudes.

Claim 24

A parameter estimation method of an induction motor, comprising: setting a point P R at an arbitrary position on a stator current vector plane; transforming measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; obtaining a difference between phases of the vectors for the measured and the observed values; and estimating a rotor resistance of the induction motor from the difference between magnitudes.

Claim 25

The parameter estimation method according to claim 17 , further comprising: obtaining a difference between phases of the vectors for the measured and the observed values; and estimating a stator resistance of the induction motor from the difference between phases.

Claim 26

A parameter estimation method of an induction motor, comprising: injecting a harmonic signal in a flux current; setting a point P Rr at an arbitrary position on a stator current vector plane; transforming harmonic components, corresponding to the harmonic signal, of measured and observed values of a stator current of the induction motor into vectors starting from the point P Rr on the stator current vector plane; obtaining a difference between magnitudes of the transformed vectors for the harmonic components of the measured and observed values; and estimating a rotor resistance of the induction motor from the difference between magnitudes.

Claim 27

A parameter estimation method of an induction motor, comprising: injecting a harmonic signal in a flux current; setting a point P Rr at an arbitrary position on a stator current vector plane; transforming harmonic components, corresponding to the harmonic signal, of measured and observed values of a stator current of the induction motor into vectors starting from the point P Rr on the stator current vector plane; obtaining a difference between magnitudes of the transformed vectors for the harmonic components of the measured and observed values; and estimating a rotor resistance of the induction motor from the difference between magnitudes.

Claim 28

The parameter estimation method according to claim 19 , further comprising: setting a point P R at an arbitrary position on a stator current vector plane; transforming unit transforming a measured and observed values of a stator current of the induction motor into vectors starting from the point P R on the stator current vector plane; obtaining a difference between phases of the vectors for the transformed measured and observed values; and estimating a rotor resistance of the induction motor from the difference between phases.