Apparatus for compensating for speed error of motor

• US 20050062448A1
• Filed: 07/02/2004
• Published: 03/24/2005
• Est. Priority Date: 09/20/2003
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Oh, Jae-Yoon, Cheong, Dal-Ho
• Granted Patent: US 7,102,309 B2
• Time in Patent Office: Days
• US Class Current: 318/268
• CPC Class Codes: F04C 2270/80 Diagnostics
• CPC Class Codes: F04C 28/28 Safety arrangements; Monitoring
• CPC Class Codes: H02P 21/05 specially adapted for damping motor oscillations, e.g. for reducing hunting
• CPC Class Codes: H02P 21/18 Estimation of position or speed
• CPC Class Codes: H02P 21/26 Rotor flux based control
• CPC Class Codes: H02P 23/16 Controlling the angular speed of one shaft H02P23/18 takes precedence
• CPC Class Codes: H02P 23/186 of one shaft by controlling the prime mover

Abstract

The present invention discloses an apparatus for compensating for a speed error of a motor which can reduce a speed ripple of the motor resulting from load characteristics, and which also can reduce vibrations and noises. The apparatus for compensating for the speed error of the motor divides a rotational section corresponding to one complete revolution of a rotor of the motor into a plurality of preset rotational sections, determines a speed compensation value in each divided rotational section on the basis of a difference value between a lo reference speed and a previous estimated speed, and compensates for the speed error of the motor on the basis of the speed compensation value.

Claims

1. An apparatus for controlling a speed of a motor of a compressor, comprising a means for dividing a rotational section corresponding to one complete revolution of a rotor of the motor into a plurality of preset rotational sections, determining a speed compensation value in each divided rotational section on the basis of a difference value between a reference speed and a previous estimated speed of the motor, and compensating for the speed error of the motor on the basis of the speed compensation value.

2. An apparatus for compensating for a speed error of a motor, which divides a rotational section corresponding to one complete revolution of a rotor of the motor into a plurality of preset rotational sections, determines a speed compensation value in each divided rotational section on the basis of a difference value between a reference speed and a previous estimated speed, and compensates for the speed error of the motor on the basis of the speed compensation value.

3. An apparatus for compensating for a speed error of a motor, comprising:

a speed compensator for dividing a rotational section corresponding to one complete revolution of a rotor of the motor into a plurality of preset rotational sections, comparing a reference speed of the motor with a previous estimated speed in each divided rotational section, calculating the speed error of the motor according to the comparison result, determining a speed compensation value for compensating for the speed error, and outputting the speed compensation value;

a comparator for comparing the speed compensation value from the speed compensator, the reference speed and a current estimated speed of the motor; and

a proportional integration controller for outputting a reference torque component current for compensating for a speed error value according to the comparison result of the comparator.

4. The apparatus of claim 3, wherein the speed compensation value Δ

ω

_m* is represented by Δ

ω

_m*=k(ω

_m−

ω

_m*),

wherein, ω

_m denotes the current estimated speed, ω

_m* denotes the reference speed, and k denotes a value for compensating for the speed error between the reference speed and the current estimated speed in the preset rotational sections.

5. The apparatus of claim 3, wherein the proportional integration controller adds the determined compensation value to the error value between the reference speed and the current estimated speed, and outputs the reference torque component current corresponding to the added value.

6. An apparatus for compensating for a speed error of a motor, comprising:

a speed compensator for comparing a reference speed of the motor with a previous estimated speed, calculating a previous speed error according to the comparison result, determining a speed compensation value for compensating for the previous speed error, and outputting the speed compensation value;

a first proportional integration controller for generating a reference current for compensating for a speed corresponding to the speed compensation value;

a first comparator for comparing the reference speed with a current estimated speed, and outputting a resulting speed error value;

a second proportional integration controller for outputting a reference torque component current for compensating for the speed error value of the first comparator;

a second comparator for comparing the reference torque component current, the reference current for compensating for the speed and a real torque component current, and outputting a resulting error value; and

a third proportional integration controller for outputting a reference torque component voltage for compensating for the error value of the second comparator.

7. The apparatus of claim 6, wherein the speed compensator divides a rotational section corresponding to one complete revolution of a rotor of the motor into a plurality of preset rotational sections, compares the reference speed with the previous estimated speed in each divided rotational section, detects the speed error in each rotational section according to the comparison result, determines the speed compensation value for compensating for the detected speed error, and outputs the speed compensation value.

8. The apparatus of claim 7, wherein the speed compensation value Δ

ω

_m* is represented by Δ

ω

_m*=k(ω

_m−

ω

_m*),

wherein, ω

_m denotes the current estimated speed, ω

_m* denotes the reference speed, and k denotes a value for compensating for the speed error between the reference speed and the current estimated speed in the preset rotational sections.