Research On Analytical Modeling And Optimal Design Method Of Electromagnetic Linear Drive Device

With the rapid development of China’s economy,the problems of environmental protection,energy conservation and emission reduction have become increasingly prominent.As the core component of the Transmission system,transmission is still the hot spot of current research.The research group proposed a Direct-Driving Automated Mechanical Transmission(DAMT)which uses electromagnetic linear driving device as the shift actuator.As the core components of DAMT,the characteristics of electromagnetic linear drive device will directly affect the performance of shifting.In this paper,the electromagnetic linear drive device for DAMT is taken as the research object,and an analytical model-based method is proposed to study the electromagnetic and temperature characteristics of the electromagnetic linear drive device.Through mathematical modeling,analytical solution,simulation and experimental verification,the mapping relationship between characteristics and dimension parameters is obtained.Based on the analytical model,a kind of structural parameter optimization scheme of electromagnetic linear drive device is proposed.Specific work is as follows:(1)A modified model of electromagnetic force based on hybrid analytical model is proposed to solve the problem of solving errors caused by different magnetization modes in practical engineering.The solutions of magnetic field distribution under the boundary conditions of the magnetic potential vector model and the equivalent surface current model are derived,and the solutions of the electromagnetic force under the magnetic potential vector model are obtained.The equivalent surface current model is used to correct the results of air gap flux density and thrust in the magnetic potential vector model.The electromagnetic force solving error caused by the simplification of the magnetic potential vector model to a two-dimensional plane under parallel magnetization is solved.The finite element model,magnetic potential vector model and hybrid analytical model are compared and verified by JMAG software,and the correctness and accuracy of the modified analytical model are verified.The maximum error of the single analytical model before modification is 6.9 %,and the maximum error of the hybrid analytical model after modification is reduced to 3.4 % and 3.5 %.The hybrid analytical model provides the electromagnetic model basis for the multi-objective optimization of the driving device.(2)The equivalent thermal network model of the electromagnetic linear drive device is established,and the steady-state temperature rise of the electromagnetic linear drive device under continuous working system is analyzed.The related concepts of heat transfer are expounded and the heat transfer type in the electromagnetic linear drive device is determined.The loss type of electromagnetic linear drive device is defined and the mathematical model of system loss is established.The 20-nodes thermal network model of the electromagnetic linear drive device and the node heat balance equations were established and solved by programming in MATLAB,and the steady-state temperature rise of each node was obtained under different working conditions.JMAG software was used to simulate the temperature field of electromagnetic linear drive device,and the correctness and accuracy of the equivalent thermal network model were verified.The results show that the solving errors of the analytical model and the finite element model are within the allowable range,especially the temperature description of permanent magnet is good,which provides the temperature rise model basis for the multi-objective optimization of the electromagnetic linear drive device.(3)The multi-objective optimization of the structural parameters of the electromagnetic linear drive device is carried out.In this paper,the optimization problem of electromagnetic linear drive system is described and the optimization objective is proposed.Combined with the hybrid electromagnetic field analytical model,equivalent thermal network model,PSO optimization algorithm and GA optimization algorithm,an optimization scheme based on the analytical model and piecewise PSO-GA algorithm was proposed,and the optimized structural parameters were obtained in MATLAB.The electromagnetic characteristics and temperature rise characteristics of the driving device before and after optimization are compared by finite element model,and the effectiveness of the optimization scheme is proved.The finite element results show that after optimization,the peak electromagnetic force of the driving device is814.92 N and the electromagnetic force fluctuation is reduced by 1.9 % compared with before optimization.Meanwhile,the temperature rise of each node in the driving device decreases,and the steady state temperature of permanent magnet decreases by 8.5 %.(4)Prototype development and test verification are realized.According to the optimized size parameters,the prototype structure was designed and assembled.The electromagnetic test platform and temperature rise test platform were built respectively,and the test process was designed.Finally,electromagnetic and temperature rise tests were carried out at room temperature to verify the correctness and accuracy of the analytical model and the finite element model.The results show that the peak electromagnetic force is 799 N and the minimum electromagnetic force is 618 N,and the error is less than 3%.In the temperature rise test,when the room temperature is 25 ℃,the steady-state temperatures of test point 1,2 and 3 are 58.2 ℃,59.3 ℃ and 59.8 ℃ respectively,and the test error is less than 8%.