Design of switched reluctance motor based electric drive-train for intra-campus two wheeler

Abstract

The intra-campus two wheeler is a vehicle used for small daily commutes inside a campus. It is characterized by low power and small range thus making it suitable for conversion into an electric vehicle. In this paper, the electric drive-train of the vehicle is designed. Generally high torque density brushless DC hub motor is preferred for this application. But to achieve constant power output, the hub motor is severely overloaded reducing overall vehicle efficiency. To improve efficiency, the field weakening capability of the electric motor is utilized. However, such a motor has high rated torque and therefore large size. Hence, a planetary gear is used between wheel and the motor as a reduction gear to reduce the motor size. Furthermore, instead of expensive permanent magnet based motors, Switched Reluctance Motor (SRM), which has good field weakening capability, is chosen for this application. It is shown that a 4 phase SRM has better field weakening capability than a 3 phase SRM. Thus a 4 phase SRM is designed and fabricated for this purpose. The SRM is to be fitted inside the rear wheel of the vehicle along with the planetary gear.