Electromagnectic rotating machine

• US 5,936,370 A
• Filed: 04/19/1996
• Issued: 08/10/1999
• Est. Priority Date: 04/21/1995
• Status: Expired due to Fees

• Current Assignee: Ebara Corporation, Nikkiso Company Limited, Seiko Seiki Co., Ltd.
• Original Assignee: Ebara Corporation Nikkiso Company Limited, Seiko Seiki Co., Ltd.
• Inventors: Fukao, Tadashi, Michioka, Chikara, Chiba, Akira
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): LOCKETT, KIMBERLY R
• Application Number:
  US08/635,031
• Time in Patent Office: 1,208 Days
• Field of Search: 318/439, 318/254, 318/138, 318/560, 318/700, 318/704, 318/721, 318/724, 318/727, 318/738, 318/799, 318/823, 310/90.5, 310/184, 310/198, 310/112
• US Class Current: 318/652
• CPC Class Codes: F16C 2360/45 Turbo-molecular pumps in general F04D19/04
• CPC Class Codes: F16C 2380/26 Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators in general H02K
• CPC Class Codes: F16C 32/0448 by using the electromagnet itself as sensor, e.g. sensorless magnetic bearings
• CPC Class Codes: F16C 32/0493 integrated in an electrodynamic machine, e.g. self-bearing motor
• CPC Class Codes: F16C 32/0497 generating torque and radial force
• CPC Class Codes: H02K 7/09 with magnetic bearings

Abstract

An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor has drive windings fitted to the stator for generating a rotating magnetic field for rotatably driving the rotor, position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the drive windings, a magnetic force generation circuit for generating a magnetic force to act on the rotor by supplying the position control windings with an electric current effective to unbalance the magnetic field on the stator side, a circuit for detecting an induced voltage or current generated in the one or more position control windings in response to radial displacement of the rotor and the rotating magnetic field generated by the drive windings, a circuit for detecting radial displacement of the rotor based on the induced voltage or current and the magnitude and speed of the rotating magnetic field, and a position control circuit for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation circuit in accordance with the detected radial displacement of the rotor.

Claims

1. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic field for rotatable driving the rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

induced state detection means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor and the rotating magnetic field generated by the one or more drive windings;

radial displacement detection means for detecting the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detection means and the magnitude and speed of the rotating magnetic field generated by the one or more drive windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the radial displacement detected by the radial displacement detection means.

2. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic field for rotatable driving the rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

electromotive force generation means for generating one of a voltage or a current which is effective to cancel an induced voltage or an induced current generated in the one or more position control windings in response to radial displacement of the rotor and the rotating magnetic field generated by the one or more drive windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the voltage or current generated by the electromotive force generation means.

3. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic field for rotatable driving the rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

an impedance circuit for determining the relation between an induced voltage and a current which are generated in the one or more position control windings in response to radial displacement of the rotor and the rotating magnetic field generated by the one or more drive windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the relation between the voltage and current which is determined by the impedance circuit.

4. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic field for rotatable driving the rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

induced state detection means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor and PWM vectors generated by the one or more drive windings;

radial displacement detection means for detecting the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detection means and space vectors of motor applied voltage generated by the one or more drive windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the radial displacement detected by the radial displacement detection means.

5. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic field for rotatably driving the rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

induced state detection means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor and the injected high frequency carrier generated by the one or more drive windings;

radial displacement detection means for detecting the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detection means and the injected high frequency carrier generated by the one or more drive windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the radial displacement detected by the radial displacement detection means.

6. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic field for rotatable driving the rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

induced state detection means for detecting one of an induced voltage and an induced current generated in one or more of the drive windings in response to radial displacement of the rotor and PWM voltage space vectors generated by the one or more drive windings;

radial displacement detection means for detecting the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detection means and the PWM voltage space vectors of motor applied voltage generated by the one or more drive windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the radial displacement detected by the radial displacement detection means.

7. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic field for rotatable driving the rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

induced state detection means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor and PWM voltage space vectors generated by the one or more position control windings;

radial displacement detection means for detecting the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detection means and PWM voltage space vectors of motor applied voltage generated by the one or more position control windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the radial displacement detected by the radial displacement detection means.

8. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic force for rotatable driving the rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

induced state detection means for detecting an induced voltage or an induced current generated in one or more of the drive windings in response to radial displacement of the rotor and an injected high frequency carrier generated by one or more of the drive windings;

radial displacement detection means for detecting the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detection means and the injected high frequency carrier generated by one or more of the drive windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the radial displacement detected by the radial displacement detection means.

9. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic field for rotatable driving the rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

induced state detection means for detecting one of an induced voltage and an induced current generated in the position control windings in response to radial displacement of the rotor and an injected high frequency carrier generated by one or more of the position control windings;

radial displacement detection means for detecting the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detection means and the injected high frequency carrier generated by one or more of the position control windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the radial displacement detected by the radial displacement detection means.

10. An electromagnetic rotating machine driven by an electromagnetic action between a stator and a rotor, the machine comprising:

one or more drive windings fitted to the stator for generating a rotating magnetic field for rotatable driving a rotor;

one or more position control windings fitted to the stator for generating a magnetic field having a different number of poles than that of the one or more drive windings;

magnetic force generation means for generating a magnetic force to act on the rotor by supplying one or more of the position control windings with an electric current sufficient to unbalance the magnetic field on the stator side so as to levitate the rotor within the stator;

an active power filter and passive device circuit for determining the relation between an induced voltage and an induced current which are generated in one or more position control windings in response to radial displacement of the rotor and the rotating magnetic field generated by the one or more drive windings; and

position control means for controlling the radial position of the rotor by changing the magnetic force generated by the magnetic force generation means in accordance with the relation between the induced voltage and induced current which is determined by the active power filter and passive device circuit.

11. An electromagnetic rotating machine comprising:

a stator defining an opening;

a rotor disposed to undergo rotational movement within the opening of the stator in response to a rotational magnetic field and to undergo radial movement within the shaft;

one or more drive windings disposed in the stator for generating a rotational magnetic field for rotatably driving the rotor;

one or more position control windings disposed in the stator for generating a magnetic field effective to levitate the rotor within the shaft; and

means for controlling the radial position of the rotor by generating one of a voltage or current effective to cancel an induced voltage or an induced current in one or more of the position control windings in response to radial displacement of the rotor so as to maintain the rotor at a desired radial position within the shaft without the need for a displacement detector for monitoring the radial position of the rotor.

12. An electromagnetic rotating machine according to claim 11;

wherein the magnetic field produced by the one or more position control windings has a different number of poles than that produced by the one or more drive windings.

13. An electromagnetic rotating machine according to claim 11;

wherein the means for controlling the radial position of the rotor comprises induced state detecting means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor, radial displacement determining means for determining the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detecting means, and means for changing the magnetic field generated by the one or more position control windings in accordance with the radial displacement determined by the radial displacement determining means.

14. An electromagnetic rotating machine according to claim 11;

wherein the means for controlling the radial position of the rotor comprises an impedance circuit for determining the relationship between an induced voltage and an induced current which are generated in one or more of the position control windings in response to radial displacement of the rotor, and means for changing the magnetic field generated by one or more of the position control windings in accordance with the relationship between the induced voltage and the induced current.

15. An electromagnetic rotating machine according to claim 11;

wherein the means for controlling the radial position of the rotor comprises induced state detecting means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor and the rotating magnetic field generated by the one or more drive windings, radial displacement determining means for determining the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detecting means, and means for changing the magnetic field generated by the one or more position control windings in accordance with the radial displacement determined by the radial displacement determining means.

16. An electromagnetic rotating machine according to claim 11;

wherein the means for controlling the radial position of the rotor comprises induced state detecting means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor and PWM vectors generated by the one or more drive windings, radial displacement determining means for determining the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detecting means and the PWM space vectors generated by one or more of the drive windings, and means for changing the magnetic field generated by the one or more position control windings in accordance with the radial displacement determined by the radial displacement determining means.

17. An electromagnetic rotating machine according to claim 11;

wherein the means for controlling the radial position of the rotor comprises induced state detecting means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor and an injected high frequency carrier generated by the one or more drive windings, radial displacement determining means for determining the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detecting means and the injected high frequency carrier generated by the one or more drive windings, and means for changing the magnetic field generated by the one or more position control windings in accordance with the radial displacement determined by the radial displacement determining means.

18. An electromagnetic rotating machine according to claim 11;

wherein the means for controlling the radial position of the rotor comprises induced state detecting means for detecting one of an induced voltage and an induced current generated in one or more of the drive windings in response to radial displacement of the rotor and PWM vectors generated by the one or more drive windings, radial displacement determining means for determining the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detecting means and the PWM space vectors generated by one or more of the drive windings, and means for changing the magnetic field generated by the one or more position control windings in accordance with the radial displacement determined by the radial displacement determining means.

19. An electromagnetic rotating machine according to claim 11;

wherein the means for controlling the radial position of the rotor comprises induced state detecting means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor and PWM vectors generated by the one or more position control windings, radial displacement determining means for determining the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detecting means and the PWM space vectors generated by one or more of the position control windings, and means for changing the magnetic field generated by the one or more position control windings in accordance with the radial displacement determined by the radial displacement determining means.

20. An electromagnetic rotating machine according to claim 11;

wherein the means for controlling the radial position of the rotor comprises induced state detecting means for detecting one of an induced voltage and an induced current generated in one or more of the drive windings in response to radial displacement of the rotor and an injected high frequency carrier generated by one or more of the drive windings, radial displacement determining means for determining the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detecting means and the injected high frequency carrier generated by one or more of the drive windings, and means for changing the magnetic field generated by the one or more position control windings in accordance with the radial displacement determined by the radial displacement determining means.

21. An electromagnetic rotating machine according to claim 11;

wherein the means for controlling the radial position of the rotor comprises induced state detecting means for detecting one of an induced voltage and an induced current generated in one or more of the position control windings in response to radial displacement of the rotor and an injected high frequency carrier generated by one or more of the position control windings, radial displacement determining means for determining the radial displacement of the rotor based on the induced voltage or the induced current detected by the induced state detecting means and the injected high frequency carrier generated by one or more of the position control windings, and means for changing the magnetic field generated by the one or more position control windings in accordance with the radial displacement determined by the radial displacement determining means.