Study On Reliability Of Switched Reluctance Motor System

Based on the current reliability research status of motor system, using SRMsystem as an example, this paper presents a reliability analysis method of motorsystem, which considers the reliability of motor system from system level andcomponent level, separately.In system level analysis, aiming at evaluating the reliability level of SRM system,there considers the influences of the topology structure, control strategy, and singlefailure mode or combination of components on the reliability of SRM system. On theMATLAB software platform, the fault simulation model of SRM system has beenestablished, and the accuracy of simulation model has been verified by comparing thesimulation results with the running results of physical system. The Markov reliabilitymodel of SRM system has been constructed based on the combination of faultsimulation results and the Markov theory, and the reliability parameters of SRMSystem can be calculated.In device level analysis, focusing on the power MOSFET, the fatigue failure ofpower MOSFET which is induced by the interaction between the device assemblestructure, packaging materials,working load and environmental load has beenanalyzed. First, the electro-thermal coupling model of power MOSFET has beenestablished based on finite element thermal simulation in MATLAB and the transientoperating temperature of each packaging layer of power MOSFET can be estimated.Secondly, combining the rain-flow count method, response-surface design method andthermal stress finite element simulation, the thermal-mechanical coupling model hasbeen established which gives the calculation method of power MOSFET cumulativeplastic strain. Finally, the thermal fatigue lifetime of power MOSFET has beenconcluded based on the combination of the Miner linear cumulative theory and theelectro-thermal-mechanical coupling model.On these bases, the direction of subsequent system design and the healthmanagement of system were pointed out.