Variable frequency drive (VFD) surge detection and response
AssigneeCarrier Corporation
InventorsDavid Ginsberg, Ismail Agirman
Life of this patent
Estimating the term…
Abstract
A chiller system is provided and includes a compressor, a variable frequency drive (VFD) to drive the compressor at variable frequencies and a chiller controller to ascertain a chiller condition and to command the VFD to drive the compressor at one of the variable frequencies based on the chiller condition at a first sampling rate. The VFD is configured to drive the compressor at the one of the variable frequencies responsive to being commanded by the chiller controller, to ascertain the chiller condition at a second sampling rate, which is substantially higher than the first sampling rate, and to alert the chiller controller accordingly.
Claims20
A chiller system, comprising:
- a compressor;
- a variable frequency drive (VFD) to drive the compressor at variable frequencies;
- and
- a chiller controller to ascertain a chiller condition and to command the VFD to drive the compressor at one of the variable frequencies based on the chiller condition at a first sampling rate,
- the VFD being configured to drive the compressor at the one of the variable frequencies responsive to being commanded by the chiller controller, to ascertain the chiller condition at a second sampling rate, which is substantially higher than the first sampling rate, and to alert the chiller controller accordingly,
- wherein the VFD is further configured to initiate an override mode during which the VFD generates an internal command to drive the compressor at one of the variable frequencies based on the chiller condition at the second sampling rate and drives the compressor at the one of the variable frequencies responsive to the internal command and to give up control by the VFD following a predefined number of internal commands being reached or a predefined time being reached.
A chiller system, comprising:
- a compressor;
- a variable frequency drive (VFD) to drive the compressor at variable frequencies;
- and
- a chiller controller to ascertain a chiller condition and to command the VFD to drive the compressor at one of the variable frequencies based on the chiller condition at a first sampling rate,
- the VFD being configured to drive the compressor at the one of the variable frequencies responsive to being commanded by the chiller controller, to ascertain the chiller condition at a second sampling rate, which is substantially higher than the first sampling rate, and to alert the chiller controller accordingly,
- wherein the chiller controller commands the VFD to drive a motor of the compressor at one of the variable frequencies to counteract the chiller condition responsive to being alerted by the VFD.
A chiller system, comprising:
- a compressor;
- a variable frequency drive (VFD) to drive the compressor at variable frequencies;
- and
- a chiller controller to ascertain a chiller condition and to command the VFD to drive the compressor at one of the variable frequencies based on the chiller condition at a first sampling rate,
- the VFD being configured to drive the compressor at the one of the variable frequencies responsive to being commanded by the chiller controller, to ascertain the chiller condition at a second sampling rate, which is substantially higher than the first sampling rate, and to initiate an override mode accordingly during which the VFD generates an internal command to drive the compressor at one of the variable frequencies based on the chiller condition at the second sampling rate and drives the compressor at the one of the variable frequencies responsive to the internal command.
A method of operating a variable frequency drive (VFD) of a chiller system in which a chiller controller ascertains a chiller condition and commands the VFD to drive a compressor at one of variable frequencies based on the chiller condition at a first sampling rate, the method being executable by the VFD and comprising:
- driving the compressor at the one of the variable frequencies responsive to being commanded by the chiller controller;
- ascertaining the chiller condition at a second sampling rate, which is substantially higher than the first sampling rate;
- and
- initiating an override mode accordingly during which the VFD generates an internal command to drive the compressor at one of the variable frequencies based on the chiller condition at the second sampling rate and drives the compressor at the one of the variable frequencies responsive to the internal command.
Dependencies are inferred from the claim text.