Sensorless Identification of the Initial Rotor Slot Position using One Active Inverter State Excitation in Induction Machines

Sensorless induction machine drives have been deeply investigated in the last three decades, showing good performance during online operation. Most of the literature is focused on methods to track the rotor position in the most accurate way. However, there has been no research on how to start up the complete sensorless drive in case there is no position sensor at any time. If a position sensor is not available at startup, the initial position of the rotor slot is unknown. Yet, this position is essential for sensorless drives that rely on saliency compensation based on LUTs that require the estimated rotor angle as input. Therefore, this paper proposes a sensorless identification strategy of the initial rotor slot position. Experimental results, carried out in a traction motor, are presented in this paper to prove the accuracy of the proposed strategy.