Reliability Analysis Of Permanent Magnet Synchronous Motor Of Electric Vehicles Under Multiple Failure Modes

As one of the most important power sources of electric vehicles.Under the influence of continuous high load,high temperature climate and other factors,the cooling effect of electric vehicle decreases.Therefore,it reflects the characteristics of small samples,complex failure mechanism and lack of life data.It is very difficult to analyze its reliability with the traditional method based on mathematical statistics.At present,most electric vehicle manufacturers can only use the software control method to control the continuous high load output of the motor in complex environment and harsh working conditions to reduce its failure probability,but this method can not solve the problem from the root.Therefore,taking the typical electric vehicle driving motor permanent magnet synchronous motor as the research object,the thesis deeply analyzes its fault mode,fault cause and fault mechanism,identifies its main failure mode,defines the failure criterion of its main failure mode,establishes the function function of its main failure mode,and carries out reliability modeling and analysis,sensitivity analysis and reliability optimization design.The main research contents include:（1）Based on the composition,structure and working principle of permanent magnet synchronous motor,the fault mode,influence and hazard analysis are carried out to determine the weak links and main failure modes of permanent magnet synchronous motor.（2）Based on the fault physics method,the functional function of the main failure modes of permanent magnet synchronous motor is established,and the reliability modeling of permanent magnet synchronous motor is carried out.（3）The reliability analysis of permanent magnet synchronous motor considering multi failure mode correlation is carried out.In view of the complex structure of permanent magnet synchronous motor of electric vehicle and the coexistence of multiple failure modes caused by bad working conditions,Copula function is used to analyze the reliability related to failure modes.（4）The sensitivity analysis of permanent magnet synchronous motor is carried out to determine the factors that have the greatest impact on the reliability index of permanent magnet synchronous motor.In order to maximize the reliability index of permanent magnet synchronous motor,its reliability optimization design is carried out.