Active control of an acoustic cooling system

Abstract

An acoustic cooling system comprising a first transducer ( 3 ) adapted for cooling by generating sound waves, a second transducer ( 4 ) adapted for cooling by generating sound waves, and a signal-processing unit ( 6 ) adapted to generate a cancellation signal for noise generated by the acoustic cooling system. The second transducer ( 4 ) is adapted to convert the cancellation signal into sound which at least partly cancels the noise.

1 . An acoustic cooling system, comprising:
 a first transducer adapted for cooling by generating sound waves,   a second transducer for cooling by generating sound waves, and   a signal processing unit for generating a cancellation signal for noise generated by the acoustic cooling system, said second transducer converting the cancellation signal into sound which at least partly cancels the noise.   
   
   
       2 . An acoustic cooling system according to  claim 1 , further comprising a noise detector configured to detect the noise generated by the acoustic cooling system, said noise detector providing a detected noise signal to the signal processing unit. 
   
   
       3 . An acoustic cooling system according to  claim 1 , wherein the signal processing unit is configured to generate a predetermined cancellation signal. 
   
   
       4 . An acoustic cooling system according to  claim 1 , wherein each transducer comprises a resonator. 
   
   
       5 . An acoustic cooling system according to  claim 1 , wherein the second transducer is excited by a signal derived by non-linear processing of a signal exciting the first transducer. 
   
   
       6 . An acoustic cooling system according to  claim 1 , wherein the driving power of the second transducer ( 4 ) substantially corresponds to the driving power of the first transducer ( 3 ). 
   
   
       7 . An acoustic cooling system according to  claim 4 , wherein the resonators extend in substantially parallel directions. 
   
   
       8 . An acoustic cooling system according to  claim 4 , wherein the resonators are arranged with a respective opening facing in generally opposing directions. 
   
   
       9 . A method of driving an acoustic cooling system, comprising the steps of:
 generating sound waves, by a first transducer adapted for cooling,   generating sound waves, by a second transducer adapted for cooling,   generating, by a signal processing unit, a cancellation signal for noise generated by the acoustic cooling system, and   converting, by said second transducer, the cancellation signal into sound which at least partly cancels the noise.   
   
   
       10 . A method according to  claim 9 , further comprising the step of, by a noise detector, detecting the noise generated by the acoustic cooling system and providing a detected noise signal to the signal processing unit. 
   
   
       11 . A method according to  claim 9 , further comprising the step of providing a predetermined cancellation signal for the signal-processing unit. 
   
   
       12 . A method according to  claim 9 , further comprising the step of directing sound waves from each transducer by means of a respective resonator.