US 6,688,124 B1 · Electronic expansion valve control for a refrigerant cooled variable frequency drive (VFD)

Abstract

A control system for a refrigerant cooled variable frequency drive (VFD) for a chiller includes a controller which controls an electronic expansion valve to attempt to maintain a heat sink for the variable frequency drive within its design operating range. When the controller is unable to maintain the heat sink within its design operating range, a load on the chiller is reduced, either by reducing the frequency of the variable frequency drive, or if the chiller includes a compressor with internal guide vanes, by partially closing the guide vanes. The power rating of the VFD can thus be optimized based on its heat generating components operating at a controlled condition, unlike an air-cooled device which is dependent on the ambient environment.

Claims4

Dependent claims

A control system for a refrigerant cooled variable frequency drive for a chiller, comprising:

first control means for controlling an electronic expansion valve to attempt to maintain a heat sink for said variable frequency drive within its design operating range said control means including means for sensing the temperature of said heat sink;
load reduction means for reducing a load on said chiller when said first control means is unable to maintain said heat sink within its design operating range;
and
wherein said chiller includes a compressor having a plurality of internal guide vanes, and wherein said load reduction means includes means for at least partially closing said plurality of internal guide vanes when said first control means in unable to maintain said heat sink within its design operating range.

1 more element

Dependencies are inferred from the claim text.

Electronic expansion valve control for a refrigerant cooled variable frequency drive (VFD)

Life of this patent

Electronic expansion valve control for a refrigerant cooled variable frequency drive (VFD)

Life of this patent

Abstract

Claims4