Magnetic noise reduction method for AC rotary electric machine, and motor control apparatus and AC rotary electric machine apparatus using the same

• US 20050073280A1
• Filed: 06/16/2004
• Published: 04/07/2005
• Est. Priority Date: 10/17/2002
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Tsuji, Hiroya, Morioka, Tatsuru, Yamakawa, Shinobu, Takai, Takatoshi, Okamura, Makoto, Wakabayashi, Kenichi, Yoshinaga, Soichi
• Granted Patent: US 7,151,354 B2
• Time in Patent Office: Days
• US Class Current: 318/727
• CPC Class Codes: H02J 3/01 Arrangements for reducing harmonics or ripples
• CPC Class Codes: H02K 19/36 Structural association of synchronous generators with auxiliary electric devices influencing the characteristic of the generator or controlling the generator, e.g. with impedances or switches
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02P 21/00 Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
• CPC Class Codes: H02P 29/50 Reduction of harmonics
• CPC Class Codes: Y02E 40/40 Arrangements for reducing harmonics

Abstract

The invention provides techniques for reducing or altering the magnetic noise of an AC rotary electric machine. A magnetic noise reducing harmonic current of order n, whose frequency is n times the frequency of the fundamental frequency component of a polyphase AC current fed to an armature of a polyphase AC rotary electric machine, is superimposed on the polyphase AC current, thereby reducing or altering a harmonic component having a frequency (n−1) times the frequency of the fundamental frequency component and occurring due to a radial magnetic excitation force acting radially on an iron core of the AC rotary electric machine. Magnetic noise is caused by a vibration whose energy is the sum of the circumferential and radial vibrations of the iron core occurring due to the magnetomotive force of the rotor, and altering the radial vibration is particularly effective in altering the magnetic noise; as the harmonic component of the radially acting magnetic excitation force, occurring due to harmonic components having frequencies 3, 5, 7, and 13 times the fundamental frequency, has a frequency 6 or 12 times the fundamental frequency, the magnetomotive force of the rotor can be effectively reduced or altered when a current having a frequency 7 or 13 times the fundamental frequency is superimposed on the stator current.

Claims

1. A magnetic noise reduction method for an AC rotary electric machine, wherein a radial vibration reducing harmonic current, whose frequency is n times (n is a natural number) the frequency of the fundamental frequency component of a polyphase AC current fed to an armature of a polyphase AC rotary electric machine, is superimposed on said polyphase AC current, thereby attenuating an (n−

1)th harmonic component, having a frequency (n−

1) times the frequency of said fundamental frequency component, that is contained in a radial vibration occurring radially about an axial center of a rotating shaft of said AC rotary electric machine due to an excitation force generated by said AC rotary electric machine or externally applied to said AC rotary electric machine.

2. A magnetic noise reduction method for an AC rotary electric machine as set forth in claim 1, wherein a radial vibration reducing harmonic current, whose frequency is 6k+1 times (k is a natural number) the frequency of the fundamental frequency component of a stator current of a three-phase AC rotary electric machine as said AC rotary electric machine, is superimposed on said stator current, thereby reducing the radial vibration of said AC rotary electric machine that has a frequency 6k times the frequency of said fundamental frequency component, as compared to the case where said superimposition is not performed.

3. A magnetic noise reduction method for an AC rotary electric machine as set forth in claim 2 wherein, by superimposing said radial vibration reducing harmonic current of order 7, a sixth harmonic component of said radial vibration is attenuated as compared to the case where said superimposition is not performed.

4. A magnetic noise reduction method for an AC rotary electric machine as set forth in claim 2 wherein, by superimposing said radial vibration reducing harmonic current of order 13, a 12th harmonic component of said radial vibration is attenuated as compared to the case where said superimposition is not performed.

5. A magnetic noise reduction method for an AC rotary electric machine as set forth in claim 2 wherein, by superimposing said radial vibration reducing harmonic currents of orders 7 and 13, sixth and 12th harmonic components of said radial vibration are simultaneously attenuated as compared to the case where said superimposition is not performed.

6. A magnetic noise reduction method for an AC rotary electric machine as set forth in claim 2, wherein the phases and amplitudes of the radial vibration reducing seventh and 13th harmonic currents are set so that the amplitude of a vector sum, taken between the sixth and 12th harmonic components of said radial vibration occurring due to the radial vibration reducing fundamental, seventh, and 13th harmonic currents and the sixth and 12th harmonic components of said radial vibration induced in said AC rotary electric machine, becomes smaller than a predetermined value.

7. A magnetic noise reduction method for an AC rotary electric machine as set forth in claim 2 wherein, by superimposing said radial vibration reducing harmonic current of order 19, an 18th harmonic component of said radial vibration is attenuated as compared to the case where said superimposition is not performed.

8. A magnetic noise reduction method for an AC rotary electric machine as set forth in claim 2 wherein, by superimposing said radial vibration reducing harmonic current of order 25, a 24th harmonic component of said radial vibration is attenuated as compared to the case where said superimposition is not performed.

9. A magnetic noise reduction method for an AC rotary electric machine as set forth in claim 1 wherein, when I1 denotes the amplitude of said fundamental frequency, In denotes the amplitude of said harmonic current, and t, x, and y respectively denote prescribed phase angles,

the fundamental frequency component of said polyphase AC current contains at least a first phase fundamental frequency component Iu1 (=I1 sin(θ

)), a second phase fundamental frequency component Iv1 (=I1 sin(θ

−

x)), and a third phase fundamental frequency component Iw1 (=I1 sin(θ

−

y)), and

said radial vibration reducing harmonic current whose frequency is n times contains at least a first phase harmonic component Iun (=In sin n(θ

+t)), a second phase harmonic component Ivn (=In sin {n(θ

+t)−

x}), and a third phase harmonic component Iwn (=In sin {n(θ

+t)−

y}), and wherein

said first phase harmonic component Iun is superimposed on said first phase fundamental frequency component Iu1, said second phase harmonic component Ivn is superimposed on said second phase fundamental frequency component Iv1, and said third phase harmonic component Iwn is superimposed on said third phase fundamental frequency component Iw1.

10. A motor control apparatus comprising:

a rotational position detector which defects the rotational position of an automotive M-phase synchronous AC rotary electric machine (M is a positive integer not smaller than

     3); and

a motor current controller which applies, based on said detected rotational position, a prescribed phase current having a prescribed fundamental frequency and amplitude to each individual phase winding of an armature of said AC rotary electric machine, wherein

said motor current controller superimposes on said polyphase AC current a radial vibration reducing harmonic current having a frequency n times (n is a natural number) the frequency of the fundamental frequency component of said phase current, and thereby attenuates an (n−

1)th harmonic component, having a frequency (n−

1) times the frequency of said fundamental frequency component, that is contained in a radial vibration occurring radially about an axial center of a rotating shaft of said AC rotary electric machine due to an excitation force generated by said AC rotary electric machine or externally applied to said AC rotary electric machine.

11. A motor control apparatus as set forth in claim 10, wherein said motor current controller superimposes at least either one of the seventh and 13th harmonic components on said phase current, and thereby attenuates the sixth or 12th harmonic component of said radial vibration occurring in a three-phase AC rotary electric machine as said AC rotary electric machine, as compared to the case where said superimposition is not performed.

12. A motor control apparatus as set forth in claim 11, wherein by superimposing said radial vibration reducing harmonic current of order 19, said motor current controller attenuates an 18th harmonic component of said radial vibration as compared to the case where said superimposition is not performed.

13. A motor control apparatus as set forth in claim 11, wherein by superimposing said radial vibration reducing harmonic current of order 25, said motor current controller attenuates a 24th harmonic component of said radial vibration as compared to the case where said superimposition is not performed.

14. A motor control apparatus as set forth in claim 10, wherein

said AC rotary electric machine is coupled to an automotive engine so as to be decouplable therefrom, and

said motor current controller superimposes said radial vibration reducing harmonic current on said polyphase AC current when said automotive engine is in a stopped condition.

15. A motor control apparatus as set forth in claim 10, wherein

said AC rotary electric machine is coupled to an automotive engine and/or to an axle so as to be capable of regenerative braking, and

said motor current controller superimposes said radial vibration reducing harmonic current on said polyphase AC current at least either when said automotive engine is in a stopped condition or when regenerative braking is being imposed.

16. A motor control apparatus as set forth in claim 10, wherein said motor current controller

obtains said radial vibration reducing harmonic current of order n that reduces or minimizes the radial vibration having a frequency (n−

1) times the frequency of said fundamental frequency component and occurring due to the application of said phase current containing at least said fundamental frequency component and a harmonic current whose frequency is n times the frequency of said fundamental frequency component, and

superimposes said radial vibration reducing harmonic current on said phase current.

17. A motor control apparatus as set forth in claim 10, wherein said motor current controller

detects as an introduced harmonic current a harmonic current contained in said phase current and having a frequency n times the frequency of said fundamental frequency component,

obtains said radial vibration reducing harmonic current of order n as a feedback control target value for reducing or minimizing the (n−

1)th harmonic component of said radial vibration for the case where said phase current does not contain said introduced harmonic current but contains only said fundamental frequency component, and

performs feedback control to asymptotically reduce the difference between said introduced harmonic current and said target value to zero.

18. An AC rotary electric machine apparatus comprising:

an AC rotary electric machine having M-phase stator coils (M is a positive integer not smaller than

     3);

an inverter having a transistor device for controlling on and off a stator current for each phase of said synchronous machine; and

an inverter control circuit which controls said transistor device on and off based on a detected or estimated rotation angle of said AC rotary electric machine, wherein

said inverter control circuit includes harmonic PWM signal generator for performing processing to output to said inverter a harmonic PWM signal having a frequency n times (n is an integer not smaller than

     2) the frequency of the fundamental frequency component of said stator current, and thereby altering the amplitude of the magnetic sound of said AC rotary electric machine that has a frequency (n−

1) times the frequency of said fundamental frequency component, as compared to the case where said processing is not performed.

19. An AC rotary electric machine apparatus as set forth in claim 18, wherein

said harmonic PWM signal generator performs processing to output to said inverter a first harmonic PWM signal having a frequency n1 times the frequency of the fundamental frequency component of said stator current and a second harmonic PWM signal having a frequency n2 times the frequency of said fundamental frequency component, and thereby increases (or reduces) the magnetic sound of said AC rotary electric machine that has a frequency (n1−

1) times the frequency of said fundamental frequency component, as compared to the case where said processing is not performed, while at the same time, reducing (or increasing) the magnetic sound of said AC rotary electric machine that has a frequency (n2−

1) times the frequency of said fundamental frequency component, as compared to the case where said processing is not performed.

20. An AC rotary electric machine apparatus as set forth in claim 18, wherein said inverter control circuit includes fundamental PWM signal generator for outputting to said inverter a fundamental PWM signal for feeding said fundamental frequency component to each of said stator coils.

21. An AC rotary electric machine apparatus as set forth in claim 18, wherein said harmonic PWM signal generator increases the noise generated by said AC rotary electric machine when said harmonic PWM signal generator is in an operating condition, as compared to when said harmonic PWM signal generator is in an stopped condition.

22. An AC rotary electric machine apparatus as set forth in claim 18, wherein said harmonic PWM signal generator reduces the magnetic sound of said AC rotary electric machine when said harmonic PWM signal generator is in an operating condition, as compared to when said harmonic PWM signal generator is in an stopped condition.

23. An AC rotary electric machine apparatus as set forth in claim 21, wherein said harmonic PWM signal generator increases or reduces said magnetic sound as compared to when said harmonic PWM signal generator is in an stopped condition, by altering the phase and/or amplitude of the harmonic current to be added to said stator current in accordance with the number of revolutions.

24. An AC rotary electric machine apparatus as set forth in claim 18, wherein said harmonic PWM signal generator performs processing to output to said inverter a harmonic PWM signal having a frequency 6k+1 times (k is a natural number) the frequency of the fundamental frequency component of said stator current, and thereby alters the magnetic sound of a three-phase AC rotary electric machine as said AC rotary electric machine that has a frequency 6k times the frequency of said fundamental frequency component, as compared to the case where said processing is not performed.

25. An AC rotary electric machine apparatus as set forth in claim 24, wherein said harmonic PWM signal generator outputs a harmonic PWM signal for superimposing a seventh harmonic current on the fundamental frequency component of said stator current, and thereby alters a sixth harmonic component of said magnetic sound as compared to the case where said superimposition is not implemented.

26. An AC rotary electric machine apparatus as set forth in claim 23, wherein said harmonic PWM signal generator outputs a harmonic PWM signal for superimposing a 13th harmonic current on the fundamental frequency component of said stator current, and thereby alters a 12th harmonic component of said magnetic sound as compared to the case where said superimposition is not implemented.

27. An AC rotary electric machine apparatus as set forth in claim 23, wherein said harmonic PWM signal generator outputs a harmonic PWM signal for superimposing seventh and 13th harmonic currents on the fundamental frequency component of said stator current, and thereby alters sixth and 12th harmonic components of said magnetic sound as compared to the case where said superimposition is not implemented.

28. An AC rotary electric machine apparatus as set forth in claim 23, wherein said harmonic PWM signal generator outputs a harmonic PWM signal for superimposing 19th and/or 25th harmonic currents on the fundamental frequency component of said stator current, and thereby alters 18th and/or 24th harmonic components of said magnetic sound as compared to the case where said superimposition is not implemented.

29. An AC rotary electric machine apparatus as set forth in claim 19, wherein

said n1 is 6k1+1 (k1 is a natural number),

said n2 is 6k2+1 (k2 is a natural number), and

said harmonic PWM signal generator, as compared to the case where said processing is not performed, reduces the magnetic sound of a three-phase AC rotary electric machine as said AC rotary electric machine that has a frequency 6k1 times the frequency of said fundamental frequency component and, at the same time, increases the magnetic sound of the three-phase AC rotary electric machine as said AC rotary electric machine that has a frequency 6k2 times the frequency of said fundamental frequency component.

30. An AC rotary electric machine apparatus as set forth in claim 29, wherein k1 is 1.

31. An AC rotary electric machine apparatus as set forth in claim 29, wherein k1 is 2.

32. An AC rotary electric machine apparatus as set forth in claim 29, wherein k1 is 3.

33. An AC rotary electric machine apparatus as set forth in claim 29, wherein k1 is 4.

34. An AC rotary electric machine apparatus as set forth in claim 24, wherein said harmonic PWM signal generator performs processing to output to said inverter a harmonic PWM signal having frequencies 7 and 13 times the frequency of the fundamental frequency component of said stator current and a harmonic PWM signal having at least either one of frequencies 19 and 25 times the frequency of said fundamental frequency component, and thereby attenuates the magnetic sound of said three-phase AC rotary electric machine as said AC rotary electric machine that has frequencies 6 and 12 times the frequency of said fundamental frequency component and the magnetic sound of said three-phase AC rotary electric machine as said AC rotary electric machine that has at least either one of frequencies 18 and 24 times the frequency of said fundamental frequency component, as compared to the case where said processing is not performed.

35. An AC rotary electric machine apparatus as set forth in claim 18, wherein when I1 denotes the amplitude of the fundamental frequency of said stator current, In denotes the amplitude of the harmonic current of said stator current, and t, x, and y respectively denote prescribed phase angles,

the fundamental frequency component of said stator current contains at least a first phase fundamental frequency component Iu1 (=I1 sin(θ

)), a second phase fundamental frequency component Iv1 (=I1 sin(θ

−

x)), and a third phase fundamental frequency component Iw1 (=I1 sin(θ

−

y)), and

said harmonic current whose frequency is n times contains at least a first phase harmonic component Iun (=In sin n(θ

+t)), a second phase harmonic component Ivn (=In sin {n(θ

+t)−

x}), and a third phase harmonic component Iwn (=In sin {n(θ

+t)−

y}), and wherein

said first phase harmonic component Iun is superimposed on said first phase fundamental frequency component Iu1, said second phase harmonic component Ivn is superimposed on said second phase fundamental frequency component Iv1, and said third phase harmonic component Iwn is superimposed on said third phase fundamental frequency component Iw1.

36. An AC rotary electric machine apparatus as set forth in claim 18, wherein

said AC rotary electric machine is coupled to an automotive engine so as to be decouplable therefrom, and

said inverter control circuit causes said magnetic sound to vary by performing processing to output said harmonic PWM signal to said inverter when said automotive engine is in a stopped condition.

37. An AC rotary electric machine apparatus as set forth in claim 18, wherein

said AC rotary electric machine is coupled to an automotive engine and/or to an axle so as to be capable of regenerative braking, and

said inverter control circuit causes said magnetic sound to vary by performing processing to output said harmonic PWM signal to said inverter at least either when said automotive engine is in a stopped condition or when regenerative braking is being imposed.

38. A motor control apparatus comprising:

a rotation angle detecting element which detects the rotational position of an automotive m-phase synchronous AC rotary electric machine (m is a positive integer not smaller than

     3); and

a motor current control element which applies, based on said detected rotational position, a phase current having a prescribed fundamental frequency and amplitude to each individual phase winding of an armature of said AC rotary electric machine, wherein

said motor control apparatus further includes a phase current detecting element which detects the phase current flowing in each phase winding, and

said motor current control element comprises;

a phase current detection value coordinate system converting element which converts the detection value (in a stationary coordinate system) of each phase current into a d-q axis coordinate system (rotating coordinate system) rotating synchronously with the fundamental frequency component of said phase current specified by an output signal of said rotation angle sensor, and outputs a d-axis detection value Id and a q-axis detection value Iq;

a fundamental command value output element which outputs a d-axis fundamental command value Id1* and a q-axis fundamental command value Iq1* as d- and q-axis components in said d-q axis coordinate system defining a fundamental command value as a target value of the fundamental frequency component of said phase current;

a harmonic command value output element which outputs a d-axis harmonic command value Id6k+1* and a q-axis harmonic command value Iq6k+1* as d- and q-axis components in said d-q axis coordinate system defining a harmonic command value as a target value of a (6k+1)th harmonic current component (k is an integer and is 0 for said fundamental frequency component);

a current deviation computing element which computes a d-axis current deviation Δ

Id and a q-axis current deviation Δ

Iq by calculating (Id1*)+(Id6k+1*)−

(Id) and (Iq*)+(Iq6k+1*)−

(Iq), respectively; and

a phase voltage control element which asymptotically reduces said d-axis current deviation Δ

Id and said q-axis current deviation Δ

Iq toward zero by controlling the phase current to be applied to each phase winding, based on said d-axis current deviation Δ

Id and said q-axis current deviation Δ

Iq, and wherein

said harmonic command value output element superimposes said d-axis harmonic command value Id6k+1* and said q-axis harmonic command value Iq6k+1* on said d-axis fundamental command value Id* and said q-axis fundamental command value Iq*, respectively, and thereby attenuates a 6k-th harmonic component, having a frequency 6k times the frequency of said fundamental frequency component, that is contained in a radial vibration occurring radially about an axial center of a rotating shaft of said AC rotary electric machine due to an excitation force generated by said AC rotary electric machine or externally applied to said AC rotary electric machine.

40. A motor control apparatus as set forth in claim 38, wherein said k is 1 and/or 2.

39. A motor control apparatus comprising:

a rotation angle detecting element which detects the rotational position of an automotive m-phase synchronous AC rotary electric machine (m is a positive integer not smaller than

     3); and

a motor current control element which applies, based on said detected rotational position, a phase current having a prescribed fundamental frequency and amplitude to each individual phase winding of an armature of said AC rotary electric machine, wherein

said motor current control element comprises;

a fundamental command value output element which outputs a d-axis fundamental command value Id1* and a q-axis fundamental command value Iq1* as d- and q-axis components in a d-q axis coordinate system defining a fundamental command value as a target value of the fundamental frequency component of said phase current;

a harmonic command value output element which outputs a d-axis harmonic command value Id6k+1 * and a q-axis harmonic command value Iq6k+1* as d- and q-axis components in said d-q axis coordinate system defining a harmonic command value as a target value of a (6k+1)th harmonic current component (k is an integer and is 0 for said fundamental frequency component);

a current command value computing element which computes a d-axis current command value Id* and a q-axis current command value Iq* by calculating (Id1*)+(Id6k+1*) and (Iq1*)+(Iq6k+1*), respectively; and

a phase voltage control element which supplies to each phase winding the phase current corresponding to said d-axis current command value Id* and said q-axis current command value Iq* by controlling the phase current to be applied to said phase winding, based on said d-axis current command value Id* and said q-axis current command value Iq*, and wherein

said harmonic command value output element superimposes said d-axis harmonic command value Id6k+1 * and said q-axis harmonic command value Iq6k+1* on said d-axis fundamental command value Id* and said q-axis fundamental command value Iq*, respectively, and thereby attenuates a 6k-th harmonic component, having a frequency 6k times the frequency of said fundamental frequency component, that is contained in a radial vibration occurring radially about an axial center of a rotating shaft of said AC rotary electric machine due to an excitation force generated by said AC rotary electric machine or externally applied to said AC rotary electric machine.