Position-sensorless control of a submersible PMSM fed over a long cable and two transformers

This paper proposes the combination of two sensorless control algorithms for the secure start-up and the efficient operation of a remotely-controlled PMSM. V / f control is applied during the start-up of the motor and vector control is used for operation at higher speeds. The investigated system consists of a long step-out configuration with a cable and two transformers between the PMSM and its VSD. The system is tested with simulations and with experiments on a lab model. The results demonstrate that V / f control can safely start the PMSM. The effect of the inertia of the rotating assembly, the load torque and the initial rotor position on the start-up performance of the system is investigated and the successful transition from V / f control to vector control is demonstrated.