Troubleshooting of Sub-synchronous Torsional Interaction Phenomena on an Electric Motor-Driven Centrifugal Compressor

Case StudyThis case study discusses the identification, troubleshooting, and correction of a torsional instability in an electric motor-driven driveline with variable frequency drive (VFD) for a high-pressure gas compressor test facility permanently installed at SwRI. A torsional instability was identified on the gearbox high-speed shaft at speeds when the VFD output (line) frequency met or exceeded the torsional natural frequency of the train. The issue was resolved by changing to sensorless vector control in the VFD instead of voltage/frequency control. In the literature, this change was not observed