Sensorless Traction System with Low Voltage High Current Induction Machine for Indoor Vehicle

Compared with DC traction application, AC electric traction is known to provide robust and low cost solution with high dynamic performances for an industrial vehicle. This embedded, compact and autonomous system is composed of a low voltage and high current induction motor (IM) fed by PWM voltage source inverter (PWM-VSI) supplied by an independent DC source (DCS battery). The authors propose the direct rotor flux oriented control (DRFOC) which allows the satisfactory dynamic performances of the this propulsion set. It is clear that low cost argument of this solution requires the high work reliability of this product and its simple maintenance. Consequently, the authors proposed the ordinary IM (without the flux sensors), its power electronics and especially, they study the sensor number minimization. So, the deterministic full order observer (DFOO), of the rotor flux is chosen in association with the stator IM current estimation obtained from one DC-link current sensor. Then, the rotation speed sensor is replaced by model reference adaptive system (MRAS) speed estimation, easily adaptable to the rotor flux DFOO. The authors validate the global control strategy of the industrial vehicle using quasi-experimental methodology with the Saber software simulations. Very satisfactory results are obtained with this control strategy in the presence of the different constraints required for this industrial vehicle electric traction