Control system for centrifugal compressor

A method of operating a centrifugal compressor, comprising:

• operating a motor of the centrifugal compressor to rotate a motor shaft of the motor, wherein the motor shaft is coupled to an impeller of the centrifugal compressor;
• monitoring acoustic energy generated during operation of the centrifugal compressor using a microphone or an acoustic sensor, wherein the microphone or the acoustic sensor is disposed outside of a motor housing of the motor and on a radial side of the motor shaft of the motor;
• processing the acoustic energy to remove any extraneous information;
• comparing the acoustic energy to a predetermined value, wherein the predetermined value corresponds to a value of acoustic energy indicative of stable operation of the centrifugal compressor;
• detecting occurrence of a surge condition in response to the acoustic energy exceeding the predetermined value during operation of the centrifugal compressor, wherein the occurrence of the surge condition corresponds to a complete reversal of flow in the centrifugal compressor;
• and
• adjusting at least one of a position of a variable geometry diffuser of the centrifugal compressor or a speed of the centrifugal compressor to remediate the surge condition in response to the surge condition being detected.