| With the increasing deterioration of environmental pollution and energy crisis,low carbon,energy saving and environmental protection have become one of the significant methods which could be conducted out to realize the sustainable development.Therefore,the countries throughout the world are pursuing the new energy electric vehicles with lower emissions,promoting the electrification of the automotive industry power system and promoting the sustainable development of the automotive technology.Permanent magnet(PM)motor with the merits of high torque density,high power factor and high efficiency has become the first option of the driving motor in the new energy electric vehicles and attracted much attentions from the automobile companies and scholars around the world.For the automotive PM motor,the vibration characteristics directly influence the high-quality operation of the electric vehicle system.The motor vibration not only radiate the noise to the outside environment,affect the driving system and environment of the motor,but also have an influence on the application period of motor.Hence,this paper would investigate a kind of leakage flux variable permanent magnet(LFV-PM)motor,and analyze the influence of electromagnetic force on the electromagnetic performances such as air-gap flux density,induced electromotive force and electromagnetic torque,etc.Meanwhile,this paper would propose a motor dsign method of the LFV-PM motor considering the electromagnetic force characteristics,design the structure and the vibration characteristics of the motor,and conduct out the corresponding the experiments.The detailed contents are shown as follow:Firstly,this paper would introduce the causes and classifications of the motor vibration and illustrate the development of the research for the motor vibration,which would provide the foundation for the following researches in this paper.Secondly,the topology structure and the distribution of magnetic field for a LFV-PM motor with 36-slot/8-pole are analyzed.And then,the formula of radial and tangential electromagnetic force considering the d-axis and q-axis current would be derived.Finally,the relationship between tangential electromagnetic force and torque characteristics is exploered,and the coupling mechanism between the radial force and the motor electromagnetic vibration is analyzed.Thirdly,based on the above analysis,the design method for the LFV-PM motor considering the distribution characteristics of the electromagnetic force would be proposed.Through the establishment of comprehensive sensitivity function and the sensitivity trade-off coefficients,the compehsive sensitivity values of the structre paramenters would be analyzed.Afterwards,the layering sensitivity method would be adopted to analyze the structure parameters of the motor,which could be utilized to select the structure parameters with higher comprehensive sensitivity values.Finally,the structure parameters for the optimal motor comprehensive performances would be obtained.Afterwards,through the establishment of the finite element model for the LFV-PM motor,the air-gap flux density,back electromotive force and the electromagnetic force distribution after the design would be verified.Based on this,multi-physics co-simulation model would be established via the finite element software,which could be used to compare and analyze modal characteristics and the vibration characterisitcs of the LFV-PM motor,verifing the efficiency of the design method.Finally,according to the design results,the structure parameters of the motor would be selected and the prototype of a LFV-PM motor with 4kW is manufactured.Meanwhile,the corresponding experiments would be carried out.The experimental results would verify the correctness and efficiency of the proposed theoretical anlysis and design method. |
