Motor control apparatus and method of controlling the same

• US 10,892,697 B2
• Filed: 04/08/2019
• Issued: 01/12/2021
• Est. Priority Date: 04/11/2018
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Aoki, Kunitoshi, Ashida, Jumpei
• Primary Examiner(s): Paul, Antony M
• Application Number:
  US16/377,356
• Publication Number:
  US 20190319565A1
• Time in Patent Office: 645 Days
• Field of Search: 31840001, 31840002, 31840014, 31840015, 318700, 318701, 318721, 318779, 318799, 318800, 318801, 31840032
• CPC Class Codes: H02P 21/0003 Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control
• CPC Class Codes: H02P 21/18 Estimation of position or speed
• CPC Class Codes: H02P 21/24 Vector control not involving the use of rotor position or rotor speed sensors
• CPC Class Codes: H02P 21/34 Arrangements for starting
• CPC Class Codes: H02P 25/03 with brushless excitation
• CPC Class Codes: H02P 6/21 Open loop start

Abstract

In order to shorten an activation time while realizing high accuracy motor control, a motor control apparatus operable to control a motor is provided. The apparatus comprises: a first drive control unit configured to drive the motor by forced commutation control; a second drive control unit configured to drive the motor by vector control; and a control unit configured to control to drive the motor by one of the first drive control unit and the second drive control unit. A first control period which is a control period in which the first drive control unit controls the motor is shorter than a second control period which is a control period in which the second drive control unit controls the motor.

Claims

1. A motor control apparatus operable to control a motor, the apparatus comprising:

one or more memories connected to one or more processors configured to function as;

a transition unit configured to transit control between first drive control for driving the motor by forces commutation control and second drive control for driving the motor by vector control; and

a control unit configured to control to drive the motor by one of the first drive control and the second drive control,

wherein

a first sampling period of the first drive control is shorter than a second sampling period of the second drive control.

2. The motor control apparatus according to claim 1, further comprising:

a detection unit configured to detect a current supplied to the motor; and

an estimation unit configured to estimate a rotation speed of the motor from the current detected by the detection unit,

wherein the second drive control unit performs the vector control based on the rotation speed estimated by the estimation unit.

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

the control unit performs control to drive the motor by the first drive control if a rotation speed of the motor is less than a predetermined threshold value, and performs control to drive the motor by the second drive control if the rotation speed of the motor is greater than or equal to the predetermined threshold value.

4. The motor control apparatus according to claim 1,

wherein the first sampling period is determined based on an amount of time required for control of the motor in the first drive control, and an amount of time required for control other than control of the motor, and

the second sampling period is determined based on an amount of time required for control of the motor in the second drive control, and an amount of time required for control other than control of the motor.

5. The motor control apparatus according to claim 1, further comprising:

a detection unit configured to detect a current supplied to the motor,

wherein the transition unit further configured to transit control among the first drive control, the second drive control, and a third drive control for driving the motor by PI control based on the current detected by the detection unit,

wherein a third sampling period of the third drive control is longer than the first sampling period and shorter than the second sampling period, and

the control unit controls to drive the motor by one of the first drive control, the second drive control, and the third drive control.

6. The motor control apparatus according to claim 5,

wherein the control unit:

controls to drive the motor by the first drive control if a rotation speed of the motor is less than a first threshold value,

controls to drive the motor by the third drive control if the rotation speed of the motor is greater than or equal to the first threshold value and less than a second threshold value which is larger than the first threshold value, and

controls to drive the motor by the second drive control if the rotation speed of the motor is greater than or equal to the second threshold value.

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

an estimation unit configured to estimate a rotation speed of the motor from the current detected by the detection unit,

wherein the transition unit further configured to transit control among the first drive control, the second drive control, the third drive control, and a fourth drive control for executing estimation by the estimation unit in addition to driving of the motor by the PI control,

wherein a fourth sampling period of which is a control period in which the fourth drive control is longer than the third sampling period and shorter than the second sampling period, and

the control performs control for driving the motor by one of the first drive control, the second drive control, the third drive control, and the fourth drive control.

8. The motor control apparatus according to claim 7,

wherein the control unit:

controls to drive the motor by the first drive control if the rotation speed of the motor is less than a first threshold value,

controls to drive the motor by the third drive control if the rotation speed of the motor is greater than or equal to the first threshold value and less than a second threshold value which is larger than the first threshold value,

controls to drive the motor by the fourth drive control if the rotation speed of the motor is greater than or equal to the second threshold value and less than a third threshold value which is larger than the second threshold value, and

controls to drive the motor by the second drive control if the rotation speed of the motor is greater than or equal to the third threshold value.

9. A method of controlling a motor control apparatus operable to control a motor,

the motor control apparatus comprising:

a transition unit configured to transit control between first drive control for driving the motor by forces commutation control and second drive control for driving the motor by vector control, and

the method comprising;

performing first control to drive the motor in a first sampling period by the first drive control; and

performing second control to drive the motor in a second sampling period by the second drive control, wherein the second sampling period is longer than the first sampling period.

10. The method according to claim 9, further comprising:

detecting a current supplied to the motor; and

estimating a rotation speed of the motor from the detected current,

wherein, the second drive control performs the vector control based on the estimated rotation speed.

11. The method according to claim 9, wherein

the first control is executed if a rotation speed of the motor is less than a predetermined threshold value, and the second control is executed if the rotation speed of the motor is greater than or equal to the predetermined threshold value.

12. The method according to claim 9, wherein

the first sampling period is determined based on an amount of time required for control of the motor in the first drive control, and an amount of time required for control other than control of the motor, and

the second sampling period is determined based on an amount of time required for control of the motor in the second drive control, and an amount of time required for control other than control of the motor.

13. The method according to claim 9,

wherein the transition unit further configured to transit control among the first drive control, the second drive control, and a third drive control for driving the motor by PI control based on a current supplied to the motor,

and

the method further comprises:

detecting a current supplied to the motor; and

performing third control to drive the motor in a third sampling period by the third drive control,

wherein the third sampling period is longer than the first sampling period and shorter than the second sampling period.

14. The method according to claim 13, wherein

the first control is executed if a rotation speed of the motor is less than a first threshold value,

the third control is executed if the rotation speed of the motor is greater than or equal to the first threshold value and less than a second threshold value which is larger than the first threshold value, and

the second control is executed if the rotation speed of the motor is greater than or equal to the second threshold value.

15. The method according to claim 13, wherein

the transition unit further configured to transit control among the first drive control, the second drive control, the third drive control, and a fourth drive control for executing estimation of a rotation speed of the motor based on a current supplied to the motor, in addition to driving of the motor by the PI control

and

the method further comprises:

performing fourth control to drive the motor in a fourth sampling period by the fourth drive control,

wherein the fourth sampling period is longer than the third sampling period and shorter than the second sampling period.

16. The method according to claim 15, wherein

the first control is executed if a rotation speed of the motor is less than a first threshold value,

the third control is executed if the rotation speed of the motor is greater than or equal to the first threshold value and less than a second threshold value which is larger than the first threshold value,

the fourth control is executed if the rotation speed of the motor is greater than or equal to the second threshold value and less than a third threshold value which is larger than the second threshold value, and

the second control is executed if the rotation speed of the motor is greater than or equal to the third threshold value.

17. A non-transitory computer-readable recording medium storing a program that causes a computer to function as a motor control apparatus operable to control a motor, the apparatus comprising:

a transition unit configured to transit control between first drive control for driving the motor by forces commutation control and second drive control for driving the motor by vector control; and

a control unit configured to control to drive the motor by one of the first drive control and the second drive control,

wherein

a first sampling period of the first drive control is shorter than a second sampling period of the second drive control.

18. The medium according to claim 17,

wherein the motor control apparatus further comprises:

a detection unit configured to detect a current supplied to the motor; and

an estimation unit configured to estimate a rotation speed of the motor from the current detected by the detection unit,

wherein the second drive control performs the vector control based on the rotation speed estimated by the estimation unit.

19. The medium according to claim 17, wherein

the control unit performs control to drive the motor by the first drive control if the rotation speed of the motor is less than a predetermined threshold value, and performs control to drive the motor by the second drive control if the rotation speed of the motor is greater than or equal to the predetermined threshold value.

20. The medium according to claim 17, wherein

the first sampling period is determined based on an amount of time required for control of the motor in the first drive control, and an amount of time required for control other than control of the motor, and

the second sampling period is determined based on an amount of time required for control of the motor in the second drive control, and an amount of time required for control other than control of the motor.