摘要 |
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.
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