Design of a switched reluctance traction drive for Electric Vehicles

The cost of an electric traction drive has a strong impact on the overall price of small electric cars. Therefore, a cost effective design of such a drive train is essential. This paper investigates the design of a switched reluctance machine for application in electric vehicles from a system perspective. The goal of the paper is to propose a design procedure, which takes into account machine, inverter, battery and mechanical system. First, relevant components of the system as well as the basic requirements are defined. Special attention is paid to the modeling of the battery and dc-link behavior, which often was neglected in previous studies. Afterwards, the machine design considerations and machine characteristics are presented. The analysis clearly shows that the entire propulsion system has to be optimized in closed form to optimize the overall efficiency. In addition, it is essential to minimize the size of the dc-link capacitor of the inverter, while reducing the influence of ripple current on the high-voltage battery.