Methods and systems for detecting and recovering from control instability caused by impeller stall
AssigneeTrane International Inc.
InventorsThomas J. CLANIN, Lee L. SIBIK
Life of this patent
Estimating the term…
Abstract
Methods and systems for detecting and recovering from control instability caused by impeller stall in a chiller system are provided. In one embodiment, an impeller stall detection and recovery component of a chiller control unit calculates a control error signal frequency spectrum for an evaporator leaving water temperature, determines whether a high frequency signal content of the control error signal frequency spectrum exceeds acceptable limits, and adjusts a surge boundary control curve downward by a predetermined incremental value in order to resolve instability caused by impeller stall.
Claims18
A method for detecting and recovering from control instability caused by impeller stall in a chiller system that includes a centrifugal compressor, a chiller control unit and one or more inlet guide vanes, the method comprising:
- calculating a chiller control error signal;
- determining a frequency spectrum of the chiller control error signal to obtain a controller error signal frequency spectrum signal;
- detecting, via the chiller control unit, whether an impeller stall event has occurred based on the controller error signal frequency spectrum signal;
- restoring stable operation of the centrifugal compressor when an impeller stall event is detected.
A chiller system comprising:
- a centrifugal compressor;
- one or more inlet guide vanes;
- and
- a chiller control unit that includes an impeller stall detection and recovery component, the impeller stall detection and recovery component includes:
- a control error signal module configured to calculate a chiller control error signal,
- a control error signal frequency spectrum module configured to determine a frequency spectrum of the chiller control error signal to obtain a controller error signal frequency spectrum signal,
- an impeller stall detection module configured to detect whether an impeller stall event has occurred based on the controller error signal frequency spectrum signal, and
- an impeller stall recovery module configured to restore stable operation of the centrifugal compressor when an impeller stall event is detected.
Dependencies are inferred from the claim text.