Design of a robust speed controller for a compressor driven by a field oriented controlled induction motor

For achieving matched flow conditions in a natural gas processing plant, the design of a robust speed controller for a compressor driven by a field oriented controlled induction motor is presented. It is shown that the torque disturbance rejection can best be handled by the incorporation of a massive flywheel. The objective of the speed controller is therefore to provide robust command tracking in the presence of the uncertainties. The robust controller is obtained by loop shaping in the frequency domain. The robust performance criteria is shown to be satisfied by the resulting controller. Finally, time domain simulations are performed to show that the compressor speed and actuator signal are within posed constraints.