Motor control method and its apparatus

• US 20040169482A1
• Filed: 02/02/2004
• Published: 09/02/2004
• Est. Priority Date: 02/25/2002
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Maeda, Toshiyuki
• Granted Patent: US 7,075,260 B2
• Time in Patent Office: Days
• US Class Current: 318/443
• CPC Class Codes: H02P 23/0004 Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control
• CPC Class Codes: H02P 27/045 whereby the speed is regulated by measuring the motor speed and comparing it with a given physical value
• CPC Class Codes: H02P 27/08 with pulse width modulation
• CPC Class Codes: H02P 6/28 Arrangements for controlling current H02P6/10 takes precedence

Abstract

A voltage detection section (11a) and current detection section (11b) detect a voltage and current supplied to a motor, and the detected voltage and current are supplied to a position detection section (12). An angular speed output from the position detection section (12) is supplied to a differentiator (13) to output an angular acceleration. A fundamental wave component extraction section (14) extracts a fundamental wave component of the angular acceleration, and the extracted fundamental wave component is supplied to an amplitude adjustment section (15). The output of the amplitude adjustment section (15) is subtracted from the average current command by a subtraction section (16). This subtraction result, current detection value, and the rotor position from the position detection section (12) are supplied to a current control section (17) to carry out the current control operation so as to obtain a current command. The current command is supplied to an inverter (4) to control the voltage and current so as to suppress the speed changing due to the load torque changing. Thus, stability is improved, and decreasing in cost is realized.

Claims

1. A motor controlling method for controlling a voltage or current applied to a motor (5) for driving periodical load (6) so as to suppress rotation speed changing of the motor (5), the method comprising the steps of:

Detecting at least a fundamental wave component of an angular acceleration; and

Controlling the voltage or current applied to the motor (5) so as to determine a phase of a fundamental wave component of output torque changing to be nearly reversed phase with respect to the phase of the fundamental wave component of the detected angular acceleration.

2. A motor controlling method as set forth in claim 1, wherein amplitude of the output torque changing is controlled so that the fundamental wave component of the angular acceleration becomes 0.

3. A motor controlling method as set forth in claim 1 or claim 2, wherein at least one of an output voltage, output current, and torque command consists of a sum of a direct current component and a fundamental wave component.

4. A motor controlling method as set forth in claim 1 or claim 2, wherein the motor (5) is a motor for driving a compressor (6), and the output voltage, current, or torque command is formed in correspondence with a torque changing waveform of the compressor (6).

5. A motor controlling method as set forth in claim 1 or claim 2, wherein the motor (5) is a motor for driving a compressor (6), and the output voltage, current, or torque command is formed to fit a typical torque changing waveform of the compressor (6).

6. A motor controlling method for controlling a voltage or current supplied to a motor (5) from an inverter (4) so as to suppress rotation speed changing of the motor (5) with respect to a periodical load (6), the method comprising the steps of;

Partially outputting negative torque from the inverter (4), and

Utilizing regeneration power during the above operation for motor driving again.

7. A motor controlling method as set forth in claim 6, further carries out compensation operation for dead time of the output voltage.

8. A motor controlling method for controlling a voltage or current supplied to a motor (5) from an inverter (4) so as to suppress rotation speed changing of the motor (5) with respect to a periodical load (6), the method comprising the step of;

Controlling the voltage or current not to exceed a current maximum value of power devices of the inverter (4) taking precedence over the suppression of rotation speed changing.

9. A motor controlling method as set forth in claim 8, wherein the method controls the voltage or current not to exceed a current maximum value of power devices of the inverter (4) by reducing the amplitude of the output torque changing.

10. A motor controlling method as set forth in claim 8, wherein the method controls the voltage or current not to exceed a current maximum value of power devices of the inverter (4) by changing the waveform of the current, voltage or torque command into a form having a lower peak current with respect to the average current.

11. A motor controlling method as set forth in claim 10, wherein the method carries out the changing of the waveform by clipping the waveform of the current, voltage or torque command with a standard value.

12. A motor controlling method for calculating information for a rotor position using a current and voltage applied to a motor (5) and the instrument constants of the motor (5), and controls the voltage or current applied to the motor (5) based upon the calculated information, the method comprising the step of;

Reducing the affection of an error of the instrument constants of the motor (5), or an error of a sensor (11a)

(11b) for detection of the current, voltage based upon characteristic property of load.

13. A motor controlling method as set forth in claim 12, wherein the method carries out the reduction of the affection of the error of the instrument constants of the motor (5), or the error of a sensor (11a)(11b) when an ordinary load is driven.

14. A motor controlling method as set forth in claim 12 or claim 13, wherein the load of the motor (5) is a compressor (6), and the method reduces the affection of the error of the instrument constants of the motor (5), or the error of a sensor (11a)(11b) utilizing the torque ripple of the compressor (6).

15. A motor controlling method as set forth in claim 14, wherein the method adjusts the instrument constants so as to determine a torque ripple ratio with respect to an average torque to be a predetermined value, the average torque being observed from a section which calculates information for a rotor position using the current and voltage applied to the motor (5) and the instrument constants of the motor (5).

16. A motor controlling method as set forth in claim 14, wherein the determined value for the torque ripple ratio is a value determined in correspondence with at least the rotation speed, torque, or current.

17. A motor controlling apparatus for controlling a voltage or current applied to a motor (5) for driving periodical load (6) so as to suppress rotation speed changing of the motor (5), the apparatus comprising:

Control means (12)(13)(14)(15)(16)(17) for detecting at least a fundamental wave component of an angular acceleration, and controlling the voltage or current applied to the motor (5) so as to determine a phase of a fundamental wave component of output torque changing to be nearly reversed phase with respect to the phase of the fundamental wave component of the detected angular acceleration.

18. A motor controlling apparatus as set forth in claim 17, wherein the control means (12)(13)(14)(15)(16)(17) controls amplitude of the output torque changing so that the fundamental wave component of the angular acceleration becomes 0.

19. A motor controlling apparatus as set forth in claim 17 or claim 18, wherein the control means (12)(13)(14)(15)(16)(17) employs a value consisting of a sum of a direct current component and a fundamental wave component, as at least one of an output voltage, output current, and torque command.

20. A motor controlling apparatus as set forth in claim 17 or claim 18, wherein the motor (5) is a motor for driving a compressor (6), and the control means (12)(13)(14)(15)(16)(17) employs a value formed in correspondence with a torque changing waveform of the compressor as the output voltage, current, or torque command.

21. A motor controlling apparatus as set forth in claim 17 or claim 18, wherein the motor (5) is a motor for driving a compressor (6), and the control means (12)(13)(14)(15)(16)(17) employs a value formed to suit a typical torque changing waveform of the compressor (6) as the output voltage, current, or torque command.

22. A motor controlling apparatus for controlling a voltage or current supplied to a motor (5) from an inverter (4) so as to suppress rotation speed changing of the motor (5) with respect to a periodical load (6), wherein the apparatus employs an inverter which partially outputs negative torque from the inverter (6), and utilizes regeneration power during the above operation for motor driving again, as the inverter (4).

23. A motor controlling apparatus as set forth in claim 22, wherein the inverter (4) further carries out compensation operation for dead time of the output voltage.

24. A motor controlling apparatus for controlling a voltage or current supplied to a motor (5) from an inverter (4) so as to suppress rotation speed changing of the motor (5) with respect to a periodical load (6), the apparatus comprising;

Control means (18) for controlling the voltage or current not to exceed a current maximum value of power devices of the inverter (4) taking precedence over the suppression of rotation speed changing.

25. A motor controlling apparatus as set forth in claim 24, wherein the control means (18) controls the voltage or current not to exceed a current maximum value of power devices of the inverter (4) by reducing the amplitude of the output torque changing.

26. A motor controlling apparatus as set forth in claim 24, wherein the control means (18) controls the voltage or current not to exceed a current maximum value of power devices of the inverter (4) by changing the waveform of the current, voltage or torque command into a form having a lower peak current with respect to the average current.

27. A motor controlling apparatus as set forth in claim 26, wherein the control means (18) carries out the changing of the waveform by clipping the waveform of the current, voltage or torque command with a standard value.

28. A motor controlling apparatus for calculating information for a rotor position using a current and voltage applied to a motor (5) and the instrument constants of the motor (5), and controls the voltage or current applied to the motor (5) based upon the calculated information, the apparatus comprising;

Affection reduction means (19) for reducing the affection of an error of the instrument constants of the motor (5), or an error of a sensor (11a)(11b) for detection of the current, voltage based upon characteristic property of load.

29. A motor controlling apparatus as set forth in claim 28, wherein the affection reduction means (19) carries out the reduction of the affection of the error of the instrument constants of the motor (5), or the error of a sensor (11a)(11b) when an ordinary load is driven.

30. A motor controlling apparatus as set forth in claim 28 or claim 29, the load of the motor (5) is a compressor (6), and the affection reduction means (19) reduces the affection of the error of the instrument constants of the motor (5), or the error of a sensor (11a)(11b) utilizing the torque ripple of the compressor.

31. A motor controlling apparatus as set forth in claim 30, wherein the affection reduction means (19) adjusts the instrument constants so as to determine a torque ripple ratio with respect to an average torque to be a predetermined value, the average torque being observed from a section which calculates information for a rotor position using the current and voltage applied to the motor (5) and the instrument constants of the motor (5).

32. A motor controlling apparatus as set forth in claim 30, wherein the affection reduction means (19) employs a value determined in correspondence with at least the rotation speed, torque, or current, as the determined value for the torque ripple ratio.