Rotating force generator for magnetic bearings

• US 5,202,824 A
• Filed: 08/06/1992
• Issued: 04/13/1993
• Est. Priority Date: 06/21/1990
• Status: Expired due to Fees

• Current Assignee: Mechanical Technology Incorporated
• Original Assignee: Mechanical Technology Incorporated
• Inventors: Chen, Hsiang M.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): AUCHTERLONIE, THOMAS
• Application Number:
  US07/925,899
• Time in Patent Office: 250 Days
• Field of Search: 364/506, 364/507, 364/508, 364/576, 364/148, 364/158, 364/159, 364/164, 364/165, 73/663-665, 73/667, 73/668, 310/51, 310/90.5, 318/126-128, 318/611, 318/623, 318/628, 318/629, 318/632, 318/649, 318/460
• US Class Current: 700/279
• 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 32/0444 Details of devices to control the actuation of the electromagnets
• CPC Class Codes: F16C 32/0493 integrated in an electrodynamic machine, e.g. self-bearing motor

Abstract

The present invention relates to apparatus for stabilizing the operation of rotational machinery, particularly machinery which uses magnetic bearings. Accelerometers sense various vibrations within the machinery. The outputs of the accelerometers are analyzed by a Fast Fourier Transform algorithm and multiplied by an array of influence coefficients to calculate desired stabilizing forces to be applied to the rotating machinery. Compensating analog voltage signals are generated in accordance therewith and transmitted to magnetic control coils within the rotating machinery.

Claims

1. An apparatus for stabilizing rotational machinery, comprising:

sensing means coupled to the rotational machinery for detecting vibrations of the rotational machinery;

a feedforward processing means response to said sensing means for calculating amplitude and phase information of at least one frequency component of said vibrations, said processing means including determining means for periodically determining if said amplitude information exceeds a predetermined threshold, said processing means further including updating means, responsive to said determining means, for updating an array of output of said information only when said predetermined threshold is exceeded;

a calculating means to calculate signals from said amplitude and phase information to compensate for said vibrations;

said calculating means including means for outputting experimental signals and calculating an array of coefficients from a response to said experimental signals and means for multiplying said array of coefficients by said array of output from said processing means;

generating means to generate said signals in said analog form; and

magnetic coils within the rotational machinery controlled to stabilize said rotational machinery by said signals in analog form.

2. The apparatus of claim 1 wherein said processing means includes Fast Fourier Transform means.

3. The apparatus of claim 2 further including a phase and frequency sensor within said rotating machinery and wherein said Fast Fourier Transform means is responsive to said phase and frequency sensor.

4. The apparatus of claim 2 further including means for subtracting substantially instantaneous displacements of the rotational machinery from said signals in analog form.

5. The apparatus of claim 4 further including means for amplifying output of said means for subtracting.

6. The apparatus of claim 5 further including means for inverting and amplifying output of said means for subtracting in parallel with said means for amplifying.

7. The apparatus of claim 6 wherein output from said means for amplifying and output from said means for inverting and amplifying are transmitted to diametrically opposed magnetic control coils within said rotating machinery.

8. An apparatus for stabilizing rotational machinery bearings, comprising:

sensing means coupled to the rotational magnetic bearings for detecting vibrations of the rotational magnetic bearings;

a feedforward processing means responsive to said sensing means for calculating amplitude and phase information of at least one frequency component of said vibrations, said processing means including determining means for periodically determining if said amplitude information exceeds a predetermined threshold, said processing means further including updating means, responsive to said determining means, for updating an array of output of said information only when said predetermined threshold is exceeded;

a calculating means to calculate signals from said amplitude and phase information to compensate for said vibrations;

said calculating means including means for outputting experimental signals and calculating an array of coefficients from a response to said experimental signals and means for multiplying said array of coefficients by said array of output from said processing means;

generating means to generate said signals in said analog form; and

magnetic coils within the rotational magnetic bearings controlled to stabilize said rotational magnetic bearings by said signals in analog form.

9. The apparatus of claim 8 wherein said processing means includes Fast Fourier Transform means.

10. The apparatus of claim 9 further including a phase and frequency sensor within said rotational magnetic bearings and wherein said Fast Fourier Transform means is responsive to said phase and frequency sensor.

11. The apparatus of claim 9 further including means for subtracting substantially instantaneous displacements of a rotor rotating within the rotational magnetic bearings from said signals in analog form.

12. The apparatus of claim 11 further including means for amplifying output of said means for subtracting.

13. The apparatus of claim 12 further including means for inverting and amplifying output of said means for subtracting in parallel with said means for amplifying.

14. The apparatus of claim 13 wherein output from said means for amplifying and output from said means for inverting and amplifying are transmitted to diametrically opposed magnetic control coils adjacent to said rotating magnetic bearings.