Method for measuring motor parameters of induction motor and control apparatus

Claim 3

The method according to claim 1, wherein the current to flow in the induction motor has a triangular waveform.

Claim 4

The method according to claim 1, wherein times at which differential values of motor current are equal and current values are different are selected as the two different times.

Claim 5

The method according to claim 1, wherein times at which differential values of motor current are different and current values are equal are selected as the two different times.

Claim 8

The method according to claim 5, wherein the current to flow in the induction motor has a triangular waveform.

Claim 9

The method according to claim 5, wherein times at which differential values of motor current are equal and current values are different are selected as the two different times.

Claim 10

The method according to claim 5, wherein times at which differential values of motor current are different and current values are equal are selected as the two different times.

Claim 13

The method according to claim 9, wherein the predetermined angular frequency ω 1 is selected in accordance with the following expression, ##EQU21## where R 1 , R 2 ', and Lσ represent a stator resistance value, a rotor resistance value, and a leakage inductance value of the induction motor, respectively, and M' represents a standard mutual inductance value of an induction motor having the same power as the induction motor to be measured.

Claim 16

The method according to claim 11, wherein the predetermined angular frequency ω 1 is selected in accordance with the following expression, ##EQU23## where R 1 , R 2 ', and Lσ represent a stator resistance value, a rotor resistance value, and a leakage inductance value of the induction motor, respectively, and M' represents a standard mutual inductance value of an induction motor having the same power as the induction motor to be measured.

Claim 17

A control apparatus for an induction motor, comprising: a driver having a variable output voltage and frequency; a motor parameter measurement system for measuring motor parameters of the induction motor driven by the driver; a slip frequency operator for deriving a slip frequency from a rotor resistance and inductance of the induction motor, an excitation current command, and a torque current command; an induction motor current command output means for deriving a current to flow in the induction motor, from the torque current command, the excitation current command, a detected or estimated rotational speed of the induction motor, and the slip frequency, so as to output a current command; and a current controller for comparing the induction motor current command and a detected current of the induction motor to output a voltage command according to a compared result; wherein the motor parameter measurement system outputs a current command having a frequency of a predetermined value or more and a current waveform of a triangular wave for setting the induction motor to be in a single-phase feed state, the current controller provides the driver with a voltage command to follow the current command, and the motor parameter measurement system solves two equations obtained from detected or commanded voltage values and detected motor current values at two different times and a current differential value to find a sum of a stator resistance value and a rotor resistance value of a T-I type equivalent circuit of the induction motor, and finds the rotor resistance value from a difference between the sum of the stator resistance value and the rotor resistance value and the known stator resistance value, the stator resistance value and the rotor resistance value being used for a slip frequency operation by the slip frequency operator and a speed estimation by a speed estimator.

Claim 18

A control apparatus for an induction motor, comprising: a driver having a variable output voltage and frequency; a motor parameter measurement system for measuring motor parameters of the induction motor driven by the driver; a slip frequency operator for deriving a slip frequency from a rotor resistance and inductance of the induction motor, an excitation current command, and a torque current command; an induction motor current command output means for deriving a current to flow in the induction motor, from the torque current command, the excitation current command, a detected or estimated rotational speed of the induction motor, and the slip frequency, so as to output a current command; and a current controller for comparing the induction motor current command and a detected current of the induction motor to output a voltage command according to a compared result; wherein the motor parameter measurement system outputs a current command having a frequency of a predetermined value or more and a current waveform of a triangular wave for setting the induction motor to be in a single-phase feed state, the current controller provides the driver with a voltage command to follow the current command, and the motor parameter measurement system solves two equations obtained from detected or commanded voltage values and detected motor current values at two different times and a current differential value to find a sum of a stator resistance value and a rotor resistance value of a T-I type equivalent circuit of the induction motor, and finds the rotor resistance value from a difference between the sum of the stator resistance value and the rotor resistance value and the known stator resistance value, the stator resistance value and the rotor resistance value being used for a slip frequency operation by the slip frequency operator and a speed estimation by a speed estimator.

Claim 19

The control apparatus according to claim 13, wherein times at which differential values of motor current are equal and current values are different are selected as the two different times.

Claim 20

The control apparatus according to claim 13, wherein times at which differential values of motor current are different and current values are equal are selected as the two different times.

Claim 21

A control apparatus for an induction motor, comprising: a driver having a variable output voltage and frequency; a motor parameter measurement system for measuring motor parameters of the induction motor driven by the driver; a slip frequency operator for deriving a slip frequency from a rotor resistance and inductance of the induction motor, an excitation current command, and a torque current command; an induction motor current command output means for deriving a current to flow in the induction motor, from the torque current command, the excitation current command, a detected or estimated rotational speed of the induction motor, and the slip frequency, so as to output a current command; and a current controller for comparing the induction motor current command and a detected current of the induction motor to output a voltage command according to a compared result; wherein the motor parameter measurement system outputs a current command having a frequency of a predetermined value or more and a current waveform of a triangular wave for setting the induction motor to be in a single-phase feed state, the current controller provides the driver with a voltage command to follow the current command, and the motor parameter measurement system solves two equations obtained from detected or commanded voltage values and detected motor current values at two different times and a current differential value to find a leakage inductance value of a T-I type equivalent circuit of the induction motor, the leakage inductance value being used for a slip frequency operation by the slip frequency operator and a speed estimation by a speed estimator.

Claim 22

A control apparatus for an induction motor, comprising: a driver having a variable output voltage and frequency; a motor parameter measurement system for measuring motor parameters of the induction motor driven by the driver; a slip frequency operator for deriving a slip frequency from a rotor resistance and inductance of the induction motor, an excitation current command, and a torque current command; an induction motor current command output means for deriving a current to flow in the induction motor, from the torque current command, the excitation current command, a detected or estimated rotational speed of the induction motor, and the slip frequency, so as to output a current command; and a current controller for comparing the induction motor current command and a detected current of the induction motor to output a voltage command according to a compared result; wherein the motor parameter measurement system outputs a current command having a frequency of a predetermined value or more and a current waveform of a triangular wave for setting the induction motor to be in a single-phase feed state, the current controller provides the driver with a voltage command to follow the current command, and the motor parameter measurement system solves two equations obtained from detected or commanded voltage values and detected motor current values at two different times and a current differential value to find a leakage inductance value of a T-I type equivalent circuit of the induction motor, the leakage inductance value being used for a slip frequency operation by the slip frequency operator and a speed estimation by a speed estimator.

Claim 23

The control apparatus according to claim 16, wherein times at which differential values of motor current are equal and current values are different are selected as the two different times.

Claim 24

The control apparatus according to claim 16, wherein times at which differential values of motor current are different and current values are equal are selected as the two different times.

Claim 25

A control apparatus for an induction motor, comprising: a driver having a variable output voltage and frequency; a motor parameter measurement system for measuring motor parameters of the induction motor driven by the driver; a slip frequency operator for deriving a slip frequency from a rotor resistance and inductance of the induction motor, an excitation current command, and a torque current command; an induction motor current command output means for deriving a current to flow in the induction motor, from the torque current command, the excitation current command, a detected or estimated rotational speed of the induction motor, and the slip frequency, so as to output a current command; and a current controller for comparing the induction motor current command and a detected current of the induction motor to output a voltage command according to a compared result; wherein the motor parameter measurement system outputs a sine wave current command having a predetermined angular frequency ω 1 for setting the induction motor to be in a single-phase feed state, the current controller provides the driver with a voltage command to follow the current command, and the motor parameter measurement system solves the following equation to find a mutual inductance value M', a leakage inductance value being used for a slip frequency operation by the slip frequency operator and a speed estimation by a speed estimator, ##EQU24## where V 1 represents a detected or commanded voltage value, I 1 represents a detected motor current value, Z represents a ratio of the voltage to the motor current |V 1 |/|I 1 |, R 1 , R 2 ', and Lσ represent a known stator resistance value, a rotor resistance value, and a leakage inductance value of a T-I type equivalent circuit of an induction motor, respectively.

Claim 26

A control apparatus for an induction motor, comprising: a driver having a variable output voltage and frequency; a motor parameter measurement system for measuring motor parameters of the induction motor driven by the driver; a slip frequency operator for deriving a slip frequency from a rotor resistance and inductance of the induction motor, an excitation current command, and a torque current command; an induction motor current command output means for deriving a current to flow in the induction motor, from the torque current command, the excitation current command, a detected or estimated rotational speed of the induction motor, and the slip frequency, so as to output a current command; and a current controller for comparing the induction motor current command and a detected current of the induction motor to output a voltage command according to a compared result; wherein the motor parameter measurement system outputs a sine wave current command having a predetermined angular frequency ω 1 for setting the induction motor to be in a single-phase feed state, the current controller provides the driver with a voltage command to follow the current command, and the motor parameter measurement system solves the following equation to find a mutual inductance value M', a leakage inductance value being used for a slip frequency operation by the slip frequency operator and a speed estimation by a speed estimator, ##EQU24## where V 1 represents a detected or commanded voltage value, I 1 represents a detected motor current value, Z represents a ratio of the voltage to the motor current |V 1 |/|I 1 |, R 1 , R 2 ', and Lσ represent a known stator resistance value, a rotor resistance value, and a leakage inductance value of a T-I type equivalent circuit of an induction motor, respectively.

Claim 27

The control apparatus according to claim 19, wherein the predetermined angular frequency ω 1 is selected in accordance with the following expression, ##EQU25## where R 1 , R 2 ', and Lσ represent a stator resistance value, a rotor resistance value, and a leakage inductance value of the induction motor, respectively, and M' represents a standard mutual inductance value of an induction motor having the same power as the induction motor to be controlled.

Claim 28

A control apparatus for an induction motor, comprising: a driver having a variable output voltage and frequency; a motor parameter measurement system for measuring motor parameters of the induction motor driven by the driver; a slip frequency operator for deriving a slip frequency from a rotor resistance and inductance of the induction motor, an excitation current command, and a torque current command; an induction motor current command output means for deriving a current to flow in the induction motor, from the torque current command, the excitation current command, a detected or estimated rotational speed of the induction motor, and the slip frequency, so as to output a current command; and a current controller for comparing the induction motor current command and a detected current of the induction motor to output a voltage command according to a compared result; wherein the motor parameter measurement system outputs a sine wave current command having a predetermined angular frequency ω 1 for setting the induction motor to be in a single-phase feed state, the current controller provides the driver with a voltage command to follow the current command, and the motor parameter measurement system solves the following equation to find a mutual inductance value M', a leakage inductance value being used for a slip frequency operation by the slip frequency operator and a speed estimation by a speed estimator, ##EQU26## where V 1 represents a detected or commanded voltage value, I 1 represents a detected motor current value, Z represents a ratio of the voltage to the motor current |V 1 |/|I 1 |, and R 1 , R 2 ', and Lσ represent a known stator resistance value, a rotor resistance value, and a leakage inductance value of a T-I type equivalent circuit of an induction motor, respectively.

Claim 29

A control apparatus for an induction motor, comprising: a driver having a variable output voltage and frequency; a motor parameter measurement system for measuring motor parameters of the induction motor driven by the driver; a slip frequency operator for deriving a slip frequency from a rotor resistance and inductance of the induction motor, an excitation current command, and a torque current command; an induction motor current command output means for deriving a current to flow in the induction motor, from the torque current command, the excitation current command, a detected or estimated rotational speed of the induction motor, and the slip frequency, so as to output a current command; and a current controller for comparing the induction motor current command and a detected current of the induction motor to output a voltage command according to a compared result; wherein the motor parameter measurement system outputs a sine wave current command having a predetermined angular frequency ω 1 for setting the induction motor to be in a single-phase feed state, the current controller provides the driver with a voltage command to follow the current command, and the motor parameter measurement system solves the following equation to find a mutual inductance value M', a leakage inductance value being used for a slip frequency operation by the slip frequency operator and a speed estimation by a speed estimator, ##EQU26## where V 1 represents a detected or commanded voltage value, I 1 represents a detected motor current value, Z represents a ratio of the voltage to the motor current |V 1 |/|I 1 |, and R 1 , R 2 ', and Lσ represent a known stator resistance value, a rotor resistance value, and a leakage inductance value of a T-I type equivalent circuit of an induction motor, respectively.

Claim 30

The control apparatus according to claim 21, wherein the predetermined angular frequency ω 1 is selected in accordance with the following expression, ##EQU27## where R 1 , R 2 ', and Lσ represent a stator resistance value, a rotor resistance value, and a leakage inductance value of the induction motor, respectively, and M' represents a standard mutual inductance value of an induction motor having the same power as the induction motor to be controlled.