Research Of Anti-direction Dual Rotor Motor Thermal Field And Cooling System Design

Recently, there has been great interest in energy-saving and environmental-friendlytechnologies, thus electric vehicle will be the main way of transportation in the future. As themain power source of electric vehicle, the performance and manufacturing of electric motordetermine the dynamic and economic performance of electric vehicle. Functioned as engine,three-phase asynchronous motor and synchronous motor are generally used on electric vehicle.The power is transformed through transmission, powertrain, final drive, differential, half rearaxle, and finally delivered to the wheels. Another type of structure is that the motor is put intowheel rim as wheel drive power source. This paper studies a new Anti-direction dual rotormotor which has independent intellectual property rights, mainly focused on the temperaturefield of the motor and the design of its cooling system.The general efficiency of the motor ranges from85%to95%, and part of its energy lossemits to the outside as the air flow and radiation, while the other part increases thetemperature of the motor. Most materials in the motor, particularly the permanent magnet andinsulating material, are sensitive to the temperature. Temperature increases will lead to adecline in magnetic properties of permanent magnets, which affects the efficiency of themotor; and once the temperature exceeds the allowable temperature of insulating materials,the material properties would change fundamentally, which results in dielectric propertiesweaken or even disappear completely, and leads to the entire motor burned eventually. Thispaper studies Anti-direction dual rotor motor, which has the structure that take the stator ofthree-phase permanent magnet synchronous motor as rotor, and take its rotor as inner rotor.Inaddition, a motor casing is added. Due to the motor rated power is larger, and its winding islocated in the inner rotor, so its cooling is very difficult.The research of Anti-direction dualrotor motor was mainly conducted as following:1. Various reasons that result in losses of motor were analysed in detail, especially theiron loss mechanism of motors, and the loss values of each part were calculated.2. A three-dimensional finite element model of the motor was established, and thetemperature fields of each internal part of the motor were solved to identify the hot spots inthe motor. Experiment was made to verify the simulation result.3. Aiming at the characteristics of the motor temperature field, three different coolingschemes were designed, and the advantages and disadvantages were analysed. A new type ofcooling system that injecting oil from the side face into motor was confirmed. The cooling effect was simulated, and the influence factors were analyzed in detail. Finally, the parametersof the schem was comfirmedThe research results make some positive influence for the design and manufacture ofanti-direction dual rotor motor and its application on electric vehicle.