| With the rapid development of economy, the sales of automobiles have been continuously growing in China. The growing rate of the automobile ownership not only leads to increasing serious oil consumption, but bring the enormous burden to the environment. Thus, controlling and reducing the environmental pollution caused by the automobiles will also become a significant project of the harmonious development of society in China. Compared to the traditional automobile, electric vehicles (EVs) have received more and more attention because of zero emissions. The development of EV will not be influenced by the type of energy and energy reserves. Further, it can actively promote the whole new energy industry developed quickly.Permanent magnet (PM) motors as the heart of EV drive system have received more attractiveness than ever before because of their distinct advantages of high efficiency, high power factor, wide constant-power operating capability, high intermittent overload capability and low acoustic noise. However, since EVs work in the states of starting, accelerating, and climbing in the very worse-case condition usually, the resulting temperature-rise may threaten the safe operation of PM motors. Hence, to ensure PM motors operate steadily and safely, an accurate thermal analysis cannot be ignored when designing them for EV applications.1. The relationship between the torque output charateristics of traction motor and the driving working condition of EV is obtained through analzing the vehicle modeling and operating characteristic of automobiles. The electromagnetic design of the permanent magnet synchronous traction motor is investigated to obtain a wide high efficiency range. Finally, comprehensive experiments are implememted on a traction motor prototype to validate the electromagnetic design scheme.2. Comparative thermal analysis of the permanent magnet synchronous motor with different winding configurations is investigated for giving some references on the choice of EV traction motor. Comparative thermal analysis mainly concentrates on losses analysis, heat flow analysis and the temperature-rise of the machine under different working conditions and a transient thermal analysis on different traction motors is investigated by finite element analysis (FEA).3. The evolution strategy is introduced and improved by implementing the weighted element fitnees in individual combination. Combining electromagnetic FEA and thermal resistance network (TRN), the electromagnetic-thermal coupling analysis is investigated by adopting the improved evolution strategy for increasing the calculated efficiency. With the improved coupling algorithm, electromagnetic and thermal performances of traction motor are calculated under different working conditions. Finally, a36kW PM traction motor prototype is fabricated to validate the proposed analysis.4. The convection heat transfer within the end-space of permanent magnet synchronous traction motor near the rotor is investigated. Based on the heat flow balance within the end-space, a thermal model is established and thermal analysis of the traction motor under different working conditions is investigated. Finally, experiments are implemented on a36kW traction motor to validate the proposed thermal model.5. An optimization design scheme of cooling water jacket is proposed by combining the thermal, fluid and mechanical. A cooling ability evaluating coefficient of cooling system is proposed. Meanwhile, the number of cooling channel and the dimension of the water channel are optimized by adopting this coefficient. With help of the mechanical FEA, the optimal position of water channel in the water jacket is obtained. Finally, thermal simulation of totally-enclosed water-cooling permanent magnet synchronous traction motor is investigated and the results show the optimized water jacket has good cooling ability. |
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