Research On Life Prediction And Reliability Testing Method Of The Electric Vehicle Drive Motor

The influence of energy and environment has made Electric Vehicle (EV) trend to human's life, and the driving motor is the core component of the EVs, whose reliability will directly impact the whole vehicle's performance and driving safety. The motor's reliability is more predominant for its severe working environment and complex operation modes. However, there is less research on the reliability of EV's driving motor, the influence factors to the motor's reliability is still unclear, so it is very important to study driving motor's reliability, life distribution and test to verify the motor's reliability for EVs.In this paper, the reliability theory and research achievement about the reliability of the traditional motor research are applied to the validity research of EV's driving motor. Taking the Permanent Magnet Synchronous Motor (PMSM) for example, the correlation studies were carried out.Combining with the vehicles environment and motor, this paper analyzed the failure modes of the driving motor and the typical reliability influencing factors, and established a fault tree model about EV's driving motor, and analyzed the weaknesses for the reliability of the driving motor, such as winding insulation, bearing and permanent magnets, etc.On the basis of fault modes and the weaknesses analysis, the reliability series model of EV's driving PMSM was established. The driving motor's reliability functions that life obeys index distribution and compound distribution were presented respectively, and the methods about parameter estimation and testing hypothesis on the different types of life distribution were analyzed. The life characteristics and estimate of evaluating the driving motor reliability pointed out.From the standpoint of the life cycle of the driving motor, this paper analyzed the reliability cycle of the driving motor, and made a focus on the reliability design of the motor, and conducted the reliability distributions and anticipations about the driving motor by virtue of proportional distribution method and stress analysis, and pointed out the design methods to improve the driving motor's reliability.Finally, combining with the actual working point distribution of the driving motor, this paper discussed testing methods about motor reliability, and pointed out that accelerating truncated test is the better way to verify the reliability of the driving motor. Combining with the acceleration test models, this paper analyzed the computing methods of accelerated coefficient and imposing methods of the accelerated stress for the driving motor, then through the LabView software, finished the automatic test programs of the driving motor and set up the experimental platform and then carried out the relevant experiments.