Vibration protection in a variable speed compressor

• US 7,895,003 B2
• Filed: 10/02/2008
• Issued: 02/22/2011
• Est. Priority Date: 10/05/2007
• Status: Active Grant

• Current Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Original Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Inventors: Caillat, Jean-Luc M.
• Primary Examiner(s): Cosimano; Edward R
• Application Number:
  US12/244,528
• Publication Number:
  US 20090093911A1
• Time in Patent Office: 873 Days
• Field of Search: 73/66, 731/68, 734/57, 734/60, 734/62, 735/70, 735/77, 735/84, 738/658, 318/445, 318/460, 318/490, 340/500, 340/540, 340/635, 340/648, 340/665, 340/669, 340/679, 340/683, 702/1, 702/33, 702/34, 702/56, 702/127, 702/182, 702/183, 702/184, 702/185, 702/187, 702/189
• US Class Current: 702/56
• CPC Class Codes: F01B 25/16 Safety means responsive to specific conditions against water hammer or the like in steam engines F01B31/34
• CPC Class Codes: F01C 20/28 Safety arrangements; Monitoring
• CPC Class Codes: F04B 39/0027 Pulsation and noise damping means
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04B 49/10 Other safety measures
• CPC Class Codes: F04C 14/28 Safety arrangements; Monitoring
• CPC Class Codes: G01H 17/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the preceding groups see provisionally also G01H1/00
• CPC Class Codes: G01M 99/00 Subject matter not provided for in other groups of this subclass
• CPC Class Codes: G05B 9/00 Safety arrangements G05B7/00 takes precedence; safety arrangements in programme-control systems G05B19/048, G05B19/406
• CPC Class Codes: G05D 19/02 characterised by the use of electric means
• CPC Class Codes: G06F 11/30 Monitoring
• CPC Class Codes: G06F 17/40 Data acquisition and logging for input to computer G06F3/00
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

Vibration protection in a compressor system with a variable speed compressor may include operating a variable speed compressor at a plurality of frequencies, measuring a plurality of vibration values associated with the plurality of frequencies, determining a frequency characteristic of the compressor system based on the plurality of vibration values, and identifying prohibited compressor frequencies based on the frequency characteristic.

Claims

1. A method of vibration protection in a compressor system with a variable speed compressor comprising:

operating a variable speed compressor at a plurality of frequencies;

measuring a plurality of vibration values associated with the plurality of frequencies;

determining a frequency characteristic of the compressor system based on the plurality of vibration values; and

identifying prohibited frequencies of the compressor based on the frequency characteristic.

2. The method of claim 1, wherein the identifying includes storing a prohibited frequency value for each frequency wherein the vibration value exceeds a maximum allowable vibration.

3. The method of claim 1, wherein the measuring includes receiving a plurality of vibration values from an accelerometer and storing the vibration values in memory.

4. The method of claim 1, further comprising:

requesting operation at a first frequency;

determining a first allowed frequency furthest from the first frequency;

operating at said first allowed frequency for a predetermined time;

determining a second allowed frequency in a direction opposite to a direction of the first allowed frequency; and

operating at said second allowed frequency for a period of time substantially equal to said predetermined time.

5. The method of claim 1, further comprising repeating the operating, measuring, determining and identifying when the compressor restarts.

6. The method of claim 1, further comprising repeating the operating, measuring, determining and identifying at a predetermined interval.

7. The method of claim 1, further comprising repeating the operating, measuring, determining and identifying when a heat pump system changes an operating mode between heating and cooling.

8. The method of claim 1, further comprising repeating the operating, measuring, determining and identifying when a measured vibration value exceeds a predetermined sweep threshold.

9. The method of claim 1, further comprising repeating the operating, measuring, determining and identifying when the ambient temperature change over a predetermined time exceeds a predetermined temperature threshold.

10. The method of claim 1, further comprising operating the variable speed compressor at a first frequency (F₁) outside of the prohibited frequencies for a first time (T₁) and operating the variable speed compressor at a second frequency (F₂) outside of the prohibited frequencies for a second time (T₂), wherein the time-averaged frequency is equal to a requested frequency F_R within the prohibited frequencies.

11. The method of claim 10, wherein the first frequency is a closest allowable upper frequency, the second frequency is a closest allowable lower frequency, and the first time T₁ is equal to a predetermined total time×

(F_R−

F₂)/(F₁−

F₂) and the second time T₂=predetermined total time−

T₁.

12. The method of claim 1, wherein the frequency characteristic includes a resonant frequency.

13. The method of claim 12, wherein the prohibited compressor frequencies include a range of the resonant frequency plus or minus a critical frequency difference.

14. The method of claim 13, wherein the critical frequency difference is at least 1 Hz.

15. The method of claim 1, wherein the frequency characteristic includes a frequency range wherein the vibration values exceed a maximum acceleration amplitude.

16. The method of claim 15, wherein the maximum acceleration amplitude (A)=4π

²×

(frequency)²×

(maximum allowable displacement).

17. The method of claim 16, wherein the maximum allowable displacement amplitude is at least 25×

10<sup>−

6</sup> meters.

18. The method of claim 1, wherein the operating includes:

operating a variable speed compressor at a minimum sweep frequency;

increasing the frequency of the variable speed compressor by a frequency increment; and

continuing the increasing until the frequency of the variable speed compressor is at least a maximum sweep frequency.

19. The method of claim 18, wherein the measuring includes measuring a vibration value associated with each frequency increment.

20. The method of claim 19, wherein the vibration value is at least one of an acceleration of the system, a velocity of the system and an amplitude of the vibration.

21. The method of claim 6, wherein the predetermined interval is once a week.

22. The method of claim 8, wherein the predetermined sweep threshold is 110% of a maximum acceleration amplitude A=4π

²×

(frequency)²×

(maximum allowable displacement).