MOTOR CONTROL APPARATUS FOR CONTROLLING MOTOR BASED ON COUNTER-ELECTROMOTIVE VOLTAGE GENERATED IN WINDING OF MOTOR

• US 20170077850A1
• Filed: 09/07/2016
• Published: 03/16/2017
• Est. Priority Date: 09/11/2015
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hamada, Shuhei, Miyazawa, Toru, Kiyama, Kota, Naoi, Masaaki
• Granted Patent: US 10,097,116 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02P 21/24 Vector control not involving the use of rotor position or rotor speed sensors
• CPC Class Codes: H02P 6/17 and for generating speed information
• CPC Class Codes: H02P 6/182 using back-emf in windings

Abstract

A motor control apparatus includes: a unit configured to determine a counter-electromotive voltage in a winding of a motor; a unit configured to determine a rotational position of a rotor of the motor based on the counter-electromotive voltage; a unit configured to determine a first velocity of the rotor, based on change in the rotational position; a correction unit configured to obtain a second velocity by correcting the first velocity based on a harmonic component included in the first velocity; and a driving unit configured to drive the motor based on the second velocity and the rotational position. The correction unit includes a unit configured to obtain the second velocity by reducing error in the first velocity that occurs due to the harmonic component.

Claims

1. A motor control apparatus comprising:

a counter-electromotive voltage determination unit configured to determine a counter-electromotive voltage that is generated in a winding of a motor;

a position determination unit configured to determine a rotational position of a rotor of the motor based on the determined counter-electromotive voltage;

a velocity determination unit configured to determine a first velocity, which is a rotational velocity of the rotor, based on change in the rotational position per unit time;

a correction unit configured to obtain a second velocity by correcting the first velocity based on a harmonic component included in the first velocity; and

a driving unit configured to drive the motor based on the second velocity and the rotational position,

wherein the correction unit includes;

an extraction unit configured to extract the harmonic component; and

an error reduction unit configured to obtain the second velocity by reducing error in the first velocity that occurs due to the harmonic component.

2. The motor control apparatus according to claim 1, wherein

the extraction unit is further configured to extract the harmonic component by obtaining an average value of the first velocity and subtracting the average value from the first velocity.

3. The motor control apparatus according to claim 1, wherein

the correction unit is further configured to obtain the second velocity by correcting an amplitude of the harmonic component according to the first velocity and subtracting the corrected harmonic component from the first velocity.

4. The motor control apparatus according to claim 1, wherein

the first velocity and the harmonic component are associated with the rotational position determined by the position determination unit, and

the correction unit is further configured to correct the first velocity based on the harmonic component associated with the rotational position.

5. The motor control apparatus according to claim 4, further comprising

a storage unit configured to store the harmonic component extracted by the extraction unit, in association with the rotational position determined by the position determination unit,

wherein the correction unit is further configured to correct the first velocity based on the harmonic component stored in the storage unit.

6. The motor control apparatus according to claim 5, wherein

an average value of harmonic components corresponding to the same rotational position extracted by the extraction unit is stored in the storage unit.

7. The motor control apparatus according to claim 6, wherein

the motor control apparatus performs a feedback control in which the motor is controlled based on a velocity deviation between a velocity command value output from a master controller and the second velocity corrected by the correction unit, and

wherein

when the extraction unit extracts a harmonic component, a control gain of the feedback control is made smaller than in a case of not extracting a harmonic component.

8. The motor control apparatus according to claim 6, wherein

when the extraction unit extracts a harmonic component, the rotational velocity of the motor is made greater than in a case of not extracting a harmonic component.

9. The motor control apparatus according to claim 6, wherein

the motor transfers driving forces to a plurality of loads, and

when the extraction unit extracts a harmonic component, a driving force of the motor is not transferred to at least one load of the plurality of loads.

10. The motor control apparatus according to claim 6, wherein

when the extraction unit extracts a harmonic component, a drive current provided to the motor is made larger than in a case of not extracting a harmonic component.

11. A motor control apparatus comprising:

a counter-electromotive voltage determination unit configured to determine a counter-electromotive voltage that is generated in a winding of a rotor of the motor;

a position determination unit configured to determine a first position, which is a rotational position of a rotor, based on the determined counter-electromotive voltage;

a correction unit configured to correct the first position based on a harmonic component included in the first position to obtain a second position;

a velocity determination unit configured to determine a rotational velocity of the rotor based on change in the second position per unit time; and

a drive unit configured to drive the motor based on the second position and the rotational velocity,

wherein the correction unit includes;

an extraction unit configured to extract the harmonic component; and

an error reduction unit configured to obtain the second position by reducing error in the first position, which occurs due to the harmonic component.

12. The motor control apparatus according to claim 11, wherein

the extraction unit is further configured to extract the harmonic component by subtracting, from the first position, an average value of both the first position and a rotational position obtained based on the rotational velocity determined by the velocity determination unit.

13. The motor control apparatus according to claim 11, further comprising

a storage unit configured to store the harmonic component extracted by the extraction unit in association with the first position,

wherein an average value of harmonic components corresponding to the same rotational position extracted by the extraction unit is stored in the storage unit.

14. The motor control apparatus according to claim 11, further comprising

a storage unit configured to store the harmonic component extracted by the extraction unit, in association with the first position,

wherein

the motor control apparatus performs a feedback control in which the motor is controlled based on a velocity deviation between a velocity command value output from a master controller and the rotational velocity of the rotor determined by the velocity determination unit, and

wherein

when the extraction unit extracts the harmonic component, a control gain of the feedback control is made smaller than in a case of not extracting the harmonic component.

15. The motor control apparatus according to claim 11, further comprising

a storage unit configured to store the harmonic component extracted by the extraction unit, in association with the first position,

wherein when the extraction unit extracts the harmonic component, the rotational velocity of the motor is made greater than in a case of not extracting the harmonic component.

16. The motor control apparatus according to claim 11, further comprising

a storage unit configured to store the harmonic component extracted by the extraction unit, in association with the first position,

wherein the motor transfers driving forces to a plurality of loads, and

wherein when the extraction unit extracts the harmonic component, a driving force of the motor is not transferred to at least one load of the plurality of loads.

17. The motor control apparatus according to claim 11, further comprising

a storage unit configured to store the harmonic component extracted by the extraction unit, in association with the first position,

wherein when the extraction unit extracts the harmonic component, a drive current provided to the motor is made larger than in a case of not extracting the harmonic component.