| In recent years,in the context of energy saving and emission reduction,new energy vehicles have been rapidly developed.DC contactors,as a switching device for switching,control and protection,play a vital role in the safety and reliability of automotive DC power supply system.At present,they are developing towards high voltage and high power.The characteristics of the contactor electromagnetic system directly determine the reliability and service life of the product.The research on the high-power DC contactor electromagnetic system has important theoretical and practical application value.In this paper,based on the comprehensive consideration of the existing contactor electromagnetic system domestic and overseas,Based on the theoretical design formula and the finite element simulation analysis,the overall design,modeling and simulation optimization of a high power DC contact electromagnetic system with rated voltage and current of 450V/150 A are carried out.First of all,according to the existing dc contactor product,determine the dc contactor adopts magnetic system structure,according to the switching load capacity of DC contactor,the contact opening distance and over travel are calculated,and analyzes the strength of magnetic fields produced by permanent magnet size,and the magnetic gap size is determined,Then the release spring and contact spring are designed.On the basis of the above,the structure size of the model,the number of coil turns,the coil wire diameter and other parameters of the model were calculated according to the theoretical formula,and the three-dimensional model of the electromagnetic system was drawn.Secondly,by establishing the finite element simulation model in Maxwell,the magnetic field of the electromagnetic system is simulated,and the magnetic field distribution cloud map and the influence of eddy current effect under different magnetic clearance and different time are obtained.Then,the factors that may affect the static electromagnetic force of the electromagnetic system are fully considered,and the static electromagnetic force curves under different magnetic materials and parameter structures are obtained,which provides a reference for the analysis and optimization of dynamic characteristics.On the basis of the static characteristic,further simulation analysis of the dynamic characteristic of the electromagnetic system,the coil current,flux,moving core displacement,speed and electromagnetic force characteristic curve,The influences of mass of different moving components,coil parameters and release spring on the dynamic characteristics of contactor are compared and analyzed.The correctness of the parameters of the simulation model is verified by experiments.Finally,based on the results of the above analysis,the optimization parameters were selected according to the requirements.With closing speed and closing time as the optimization objectives,the orthogonal experiment method was adopted to design the experimental scheme under three levels and four factors,and then the range analysis method was adopted to find the optimal combination in line with the optimization objectives.The temperature field of the electromagnetic system was simulated and analyzed,and the coil temperature appreciation was obtained.Then,the dynamic characteristics of the electromagnetic system under thermal stability were analyzed.Finally,the prototype was tested and verified,and the design and optimization tasks were completed. |
