Controlling air movers based on acoustic signature

Abstract

In a system that employs multiple air movers (e.g., fans) within an enclosure, the air movers are controlled in an attempt to optimize cooling efficiency of the system. In some aspects, current cooling efficiency is indicated based on one or more characteristics of an acoustic signature in the enclosure. In particular, a reduction in cooling efficiency may be indicated by spreading of an acoustic peak of the acoustic signature. Accordingly, improved cooling efficiency may be achieved by controlling the air movers in a manner that reduces spreading of such an acoustic peak.

1 . A control apparatus for controlling a plurality of fans in an enclosure, comprising:
 a receiver circuit to receive signals representative of an acoustic signature due to interaction of the fans in the enclosure; and   a control circuit to generate control signals based on the received signals, wherein the control signals control the fans to reduce spreading of at least one acoustic peak of the acoustic signature.   
     
     
         2 . The apparatus of  claim 1 , wherein the received signals are generated by at least one acoustic transducer in the enclosure. 
     
     
         3 . The apparatus of  claim 2 , wherein:
 the receiver circuit receives a series of other signals generated by the at least one acoustic transducer over time;   the other signals are representative of other acoustic signatures due to other interactions of the fans; and   the control circuit adjusts at least one of the control signals based on the received other signals.   
     
     
         4 . The apparatus of  claim 3 , wherein the other signals are received continuously. 
     
     
         5 . The apparatus of  claim 1 , wherein the received signals are generated by at least one microphone in the enclosure. 
     
     
         6 . The apparatus of  claim 1 , wherein the received signals are generated by at least one pressure transducer in the enclosure. 
     
     
         7 . The apparatus of  claim 1 , wherein:
 the generation of the control signals comprises generating frequency spectrum information based on the received signals; and   the frequency spectrum information represents the acoustic signature.   
     
     
         8 . The apparatus of  claim 7 , wherein the at least one acoustic peak of the acoustic signature comprises a peak of the frequency spectrum information, and wherein the generation of the control signals comprises:
 identifying a spread of the peak of the frequency spectrum information; and   adjusting at least one of the control signals to reduce the spread of the peak of the frequency spectrum information.   
     
     
         9 . The apparatus of  claim 1 , wherein:
 the fans induce air flows in the enclosure;   rotational speeds of the fans are modulated due to interaction of the air flows with the fans, thereby causing the spreading; and   the control signals change the rotational speeds of the fans to reduce the modulation.   
     
     
         10 . The apparatus of  claim 1 , wherein:
 the fans induce air flows in the enclosure;   rotational speeds of the fans are modulated due to interaction of the air flows with the fans, thereby causing the spreading; and   the control signals change at least one relative phase between at least two of the fans to reduce the modulation.   
     
     
         11 . The apparatus of  claim 1 , further comprising a second receiver circuit to receive other signals indicative of temperature in the enclosure, wherein the generation of the control signals is further based on the received other signals. 
     
     
         12 . The apparatus of  claim 1 , further comprising a second receiver circuit to receive other signals indicative of rotational speeds of the fans, wherein the generation of the control signals is further based on the received other signals. 
     
     
         13 . The apparatus of  claim 12 , wherein the generation of the control signals limits the rotational speeds of the fans to be within at least one defined range of rotational speeds. 
     
     
         14 . The apparatus of  claim 1 , further comprising a second receiver circuit to receive other signals relating to operation of the fans, wherein the generation of the control signals is further based on the received other signals. 
     
     
         15 . The apparatus of  claim 14 , wherein the other signals relating to the operation of the fans comprise at least one of the group consisting of: signals indicative of power supplied to the fans, signals indicative of current supplied to the fans, and signals indicative of voltage supplied to the fans. 
     
     
         16 . The apparatus of  claim 1 , wherein the acoustic signature comprises fan blade passing noise. 
     
     
         17 . The apparatus of  claim 1 , wherein the acoustic signature comprises noise resulting from interactions of air flows induced by the fans. 
     
     
         18 . The apparatus of  claim 1 , wherein the enclosure comprises a housing for a computing system. 
     
     
         19 . The apparatus of  claim 1 , wherein the enclosure comprises: a housing for the fans, a housing for a personal computer, or a housing for a computer server. 
     
     
         20 . The apparatus of  claim 1 , wherein the control circuit employs an optimization algorithm that uses information derived from the received signals to maintain the spreading within a defined target value. 
     
     
         21 . The apparatus of  claim 1 , wherein the apparatus comprises an integrated circuit. 
     
     
         22 . A method for controlling a plurality of fans in an enclosure, comprising:
 receiving signals representative of an acoustic signature due to interaction of the fans in the enclosure; and   generating control signals based on the received signals, wherein the control signals control the fans to reduce spreading of at least one acoustic peak of the acoustic signature.   
     
     
         23 . The method of  claim 22 , wherein the received signals are generated by at least one acoustic transducer in the enclosure. 
     
     
         24 . The method of  claim 23 , further comprising:
 receiving a series of other signals generated by the at least one acoustic transducer over time, wherein the other signals are representative of other acoustic signatures due to other interactions of the fans; and   adjusting at least one of the control signals based on the received other signals.   
     
     
         25 . The method of  claim 24 , wherein the other signals are received continuously. 
     
     
         26 . The method of  claim 22 , wherein the received signals are generated by at least one microphone in the enclosure. 
     
     
         27 . The method of  claim 22 , wherein the received signals are generated by at least one pressure transducer in the enclosure. 
     
     
         28 . The method of  claim 22 , wherein:
 the generation of the control signals comprises generating frequency spectrum information based on the received signals; and   the frequency spectrum information represents the acoustic signature.   
     
     
         29 . The method of  claim 28 , wherein the at least one acoustic peak of the acoustic signature comprises a peak of the frequency spectrum information, and wherein the generation of the control signals comprises:
 identifying a spread of the peak of the frequency spectrum information; and   adjusting at least one of the control signals to reduce the spread of the peak of the frequency spectrum information.   
     
     
         30 . The method of  claim 22 , wherein:
 the fans induce air flows in the enclosure;   rotational speeds of the fans are modulated due to interaction of the air flows with the fans, thereby causing the spreading; and   the control signals change the rotational speeds of the fans to reduce the modulation.   
     
     
         31 . The method of  claim 22 , wherein:
 the fans induce air flows in the enclosure;   rotational speeds of the fans are modulated due to interaction of the air flows with the fans, thereby causing the spreading; and   the control signals change at least one relative phase between at least two of the fans to reduce the modulation.   
     
     
         32 . The method of  claim 22 , further comprising receiving other signals indicative of temperature in the enclosure, wherein the generation of the control signals is further based on the received other signals. 
     
     
         33 . The method of  claim 22 , further comprising receiving other signals indicative of rotational speeds of the fans, wherein the generation of the control signals is further based on the received other signals. 
     
     
         34 . The method of  claim 33 , wherein the generation of the control signals limits the rotational speeds of the fans to be within at least one defined range of rotational speeds. 
     
     
         35 . The method of  claim 22 , further comprising receiving other signals relating to operation of the fans, wherein the generation of the control signals is further based on the received other signals. 
     
     
         36 . The method of  claim 35 , wherein the other signals relating to the operation of the fans comprise at least one of the group consisting of: signals indicative of power supplied to the fans, signals indicative of current supplied to the fans, and signals indicative of voltage supplied to the fans. 
     
     
         37 . The method of  claim 22 , wherein the acoustic signature comprises fan blade passing noise. 
     
     
         38 . The method of  claim 22 , wherein the acoustic signature comprises noise resulting from interactions of air flows induced by the fans. 
     
     
         39 . The method of  claim 22 , wherein the enclosure comprises a housing for a computing system. 
     
     
         40 . The method of  claim 22 , wherein the enclosure comprises: a housing for the fans, a housing for a personal computer, or a housing for a computer server. 
     
     
         41 . The method of  claim 22 , wherein the generation of the control signals comprises employing an optimization algorithm that uses information derived from the received signals to maintain the spreading within a defined target value. 
     
     
         42 . A control apparatus for controlling a plurality of fans in an enclosure, comprising:
 means for receiving signals representative of an acoustic signature due to interaction of the fans in the enclosure; and   means for generating control signals based on the received signals, wherein the control signals control the fans to reduce spreading of at least one acoustic peak of the acoustic signature.   
     
     
         43 . A control system for a plurality of fans in an enclosure, comprising:
 at least one transducer to generate signals representative of an acoustic signature due to interaction of the fans in the enclosure;   a receiver circuit to receive the signals from the at least one transducer; and   a control circuit to generate control signals based on the received signals, wherein the control signals control the fans to reduce spreading of at least one acoustic peak of the acoustic signature.   
     
     
         44 . A computer-program product for controlling a plurality of fans in an enclosure, comprising:
 computer-readable medium comprising code for causing a computer to:
 receive signals representative of an acoustic signature due to interaction of the fans in the enclosure; and 
 generate control signals based on the received signals, wherein the control signals control the fans to reduce spreading of at least one acoustic peak of the acoustic signature.