PM assisted synchro-reluctance machines present the advantage of a good trade-off between low amount of magnets, low ripples on torque and wide range speed. This feature makes them suitable for applications like Electric Vehicles (EV). Indeed, carmakers show increasing interest to this type of electric machines allowing them to meet targets on EV’s requirements at lower costs. However, the behavior of PM assisted synchro-reluctance machines depends tightly on their magnetic saturation level. Therefore, a good design is involves to meet required specifications for EV applications. Furthermore, magnetic saturation makes supply and control of PM assisted synchro-reluctance machines more complex, particularly in flux weakening zone and in case of failures in the power train.
In this PhD thesis, the main objective is to design a PM assisted synchro-reluctance machine for an electric vehicle. The design specifications are defined to achieve Euro 6 emission standards requirements. The design procedure uses a finite element technique and its outcome is all parameters necessary for a dq model: stator flux as function of stator currents taking into account magnetic saturation and cross coupling effects, stator resistance and PM flux.
Then, a fault-tolerant voltage-source inverter has to be designed to supply the machine. Here, the objective is to ensure the ability of the power electronic device to keep supplying the machine under some switch failures. The other contribution is related to the control of the inverter. Indeed, the above-mentioned model has to be applied to develop nonlinear control laws to achieve target performances on the EV power train. Moreover, the control law should show fault-tolerance properties with respect to mechanical sensor failure.