Sensorless Control of Medium Voltage Induction Motor with LC Filter and Long Cable in Oil Pump Applications

A medium voltage induction motor drive for a submarine oil pump is considered in this paper. In the considered application, the inverter is located on the oil platform, whereas the submersible oil pump is located under the sea and it is supplied with a 20-km long cable. Moreover, an LC filter is located at the inverter output on the platform. In addition, since all the motor sensors should be maintained with submarine robots, stator voltage, stator current and rotor speed sensors are not installed on the motor for reliability reasons. In this study, a new sensorless control is developed. The proposed control integrates a voltage drop compensation and a stator voltage-current estimation into a sensorless control based on a Luenberger Observer. The effectiveness of the proposed control is proved by experimental tests on a low voltage motor, on a 6.6 kV-710 kW motor and on a 2.1 MW-10.5 kV motor.