Patent ID: 7854596
Filing Date: 2010-12-21
Classification: F04B,F04C,Y10S

Abstract:
1. A circuit for controlling a rotational speed and a phase of operation of each of at least two compressors, comprising: a first phase-lock loop circuit associated with a reference compressor; a second phase-lock loop circuit associated with a second compressor; the second phase-lock loop circuit being interconnected with the first phase-lock loop circuit in a closed feedback loop; wherein the first phase-lock loop circuit is configured to detect a difference between a phase of a first pressure pulse waveform generated by the first phase-lock loop circuit and a phase of a second pressure pulse waveform generated by the second phase-lock loop circuit, and to generate an error signal proportional to a detected difference in phase between the first and second pressure pulse waveforms; and an analog-to-digital converter configured to process the error signal for input to a speed controller operatively connected to the second compressor to control the rotational speed of the second compressor to be substantially equal to the rotational speed of the reference compressor, and to control the phase of the second pressure pulse waveform relative to the phase of the first pressure pulse waveform in response to the processed error signal; wherein the speed controller adjusts the phase of the second pressure pulse waveform opposite to the phase of the first pressure pulse waveform.