Design and analysis of dual rotor motor for electric vehicle application

Increasing global warming and limited reserves of fossil fuels have created the need for alternatives to conventional internal combustion engines (ICE) based vehicles as primary mode of transport. In present time, Electric Vehicles (EV) are being seen as the solution for these problems. EVs integrated with renewable energy sources, completely eliminate dependence on fossil fuel as well as can drastically reduce emission of greenhouse gases. Therefore, a lot of attention is being given to the development of efficient, reliable and cost effective EVs by automobile industry as well as academic institutions. Electric powertrain consisting of electric motor, drive system and battery as the main source of energy, is the most important part of an EV. Among all these parts, electric motor is responsible for driving the vehicle. Therefore, its rating, efficiency, control, cost etc. are very important factors from EV application viewpoint. Therefore, design and analysis of a motor suitable for EV application have been chosen as the aims for this thesis. Different types of motors can be used for EVs. EVs operating with induction motor, permanent magnet brushless DC motor and brushed DC motors have been manufactured by vehicle manufacturers. The thesis begins with a review of various type of motors used for EVs. A qualitative comparison of different motors has been presented. Subsequently, a need for a Dual Rotor Motor (DRM) having advantages of these motors and improving on their shortcomings is highlighted. The second part of the thesis focuses on various possible configurations of DRM and describes the approach that has been adopted to finalize a configuration for further design and analysis. The third part of the thesis deals with the analysis models developed for understanding of working principle and performance calculation of DRM. A 2-D analytical model using TH-1842_11610205 subdomain model approach has been developed to calculate air-gap magnetic field as well as electromagnetic torque in the motor. For quick performance calculation of DRM steady state model comprising of electrical equivalent circuit and torque equation has been developed. The final part of the thesis describes the design, prototyping and testing of DRM. Detailed electrical and mechanical design of DRM is presented. Pictures of different motor parts at different stages of manufacturing are given for practical visualization. The analysis models developed in the third part of the thesis have been validated with the experimental results in the testing of DRM section. The prototype of DRM presented in the thesis is not an optimized one and power density and efficiency of the motor were not focused on. The presented motor is first prototype in the ongoing research work and thus considering the mechanical complexities and availability of resources, the scope of the practical work was limited to proof of concept of DRM and understanding of challenges involved. The lessons learnt during the process will be implemented during manufacturing of subsequent prototypes of DRM.