This paper deals with a comparative study using numerical simulations between the failures effect caused by the speed sensor faults for a propulsion control system (PCS) of an electrical vehicle (EV) using dual-induction motors structure. The PCS strategies are achieved on two types of controls where the first one is done from a flux-oriented control (FOC) and the second one is conducted from a direct torque control (DTC). For an electric vehicle, we will often guarantee service continuity, in spite of the occurred faults such as an offset fault in speed sensor and a zero-feedback sensor speed fault which both are essentially needed in the structure of the PCS-EV. The occurred fault cited above might influence one of the dual induction motors which could be conducted an unbalance in the dual used motors and from which the control of the vehicle might be also lost. The results of the realized numerical simulations on the EV conducted by the PCS demonstrate clearly the impact of the so-called-fault. Thereafter, we can also appreciate the robustness using each used control propulsion system in despite of the occurred speed sensor fault.

Efficiency improvement is an important challenge for electric motor driven systems. For an induction motor, operation under rated conditions (at rated load with rated flux) is very efficient. However, in many situations, operation with rated flux causes low efficiency especially at light load ranges. In these applications, induction motor should operate at reduced flux which causes a balance between iron losses and copper losses leading to an improved efficiency. This paper concerns energy optimization, i.e. efficiency improvement is carried out via a controller designed on the basis of imposing the rated power factor, by finding a relationship between rotor flux and torque current component which can optimize the compromise between torque and efficiency in steady state as well as in transient state. Experimental results are presented to prove the effectiveness and validity of the proposed controller.