BACKGROUND

The disclosure generally relates to the field of data processing and to measuring, calibrating, or testing.

In the oil and gas industry, electric submersible pumps (ESPs) are used for the recovery of oil and gas from subsurface formations. ESPs are often suspended vertically in a wellbore and are connected by a cable to a motor which drives the ESP. Permanent magnet motors (PMMs) are often used in ESP systems because they are more energy efficient than inductive motors and reduce power costs. However, during PMM startup, torsional excitation and disturbances of the electrical systems in the motor may generate an unsteady torque which can lead to oscillations in the motor. These oscillations in the motor can be transferred into the shaft of the ESP causing damage to the long, slender ESP components below the earth's surface. Once the ESP components are damaged, the ESP may need to be removed from the wellbore and replaced.

