Redundancy of angular speed sensors in a double induction machine rear drive for EV

This paper focuses on the redundancy of angular speed sensors in an electric vehicle with two independent single wheel drives at the rear axle. Operation of both drives with a single angular speed sensor, e.g. in case of a sensor fault, is investigated. By applying a speed-sensorless control algorithm, operation of the faulty single wheel drive is still possible. Although speed-sensorless control of induction machines is state of the art and has been demonstrated by a variety of publications, stable operation at zero and very low speed is still not reliably possible. In this paper, a stable approach for speed-sensorless control at low and zero speed is proposed, which uses the speed sensor information of the other single wheel drive and the overall vehicle physics. Based on a detailed mechanical drive train model, the influence of the induction machine control strategy and the different road surfaces on the drive dynamics and the resulting torsional vibrations are investigated.