Simulation And Optimization Of Electromagnetic Interference Based On Automobile Cooling System

After the 20 th century,the automotive industry developed rapidly,and competition in the automotive market became increasingly fierce.Today,the "Belt and Road" strategy and the "National Brand Plan" are jointly promoted,which is an important opportunity for China's independent automobile brands to develop to high quality.With the rapid increase in the application of automotive electronic equipment in various vehicle systems,the problem of automotive electromagnetic compatibility is bound to become increasingly serious.In the traditional automobile industry,the electromagnetic compatibility of a product is often gradually improved through multiple experimental methods.Because the product already has a prototype,it is necessary to take measures to solve the problem when it is found.The measures are limited and costly.To solve the EMC problem in vehicles,it is necessary to change from posterior to a priori.It is the most important thing to carry out effective EMC analysis on the products in the early stage of vehicle design.This article first explains the current status of research on automotive EMC at home and abroad,and the basic knowledge used in EMC analysis,including Maxwell's equation,boundary conditions of time-varying electric fields,dynamic potential,D'Alembert's equation,electromagnetic power flow,Poynting vector,Near-field area and far-field area;secondly,establish an international example TEAM problem 7 finite element model to verify the fast calculation method based on Fourier transform;analyze the mechanism of electromagnetic interference generated by the pump module,establish a finite element model of electromagnetic interference and apply the fast The algorithm verifies the correctness of the fast algorithm and the simulation results of the radiation interference of the pump module.The EMSCAN electromagnetic interference scanning system is used to build the radiation experiment platform of the pump module controller.The electromagnetic noise of the pump controller during normal operation is measured,combined with the simulation.The results analyze the reasons for the radiation of high-power circuits.Finally,based on the introduction of the radiation pattern,the far-field radiation capability of the main circuit of the pump module controller is analyzed;and two optimization methods are added to increase the top layer of the circuit board and increase the ground layer.Effect of radiated far-field gain..The research results show that the fast algorithm based on Fourier transform can effectively reduce the calculation time and the amount of calculations.The accuracy of the fast algorithm is proved by combining the experimental measurement of the electromagnetic interference intensity spectrum of the pump module;the radiation characteristics of the main circuit of the pump module controller are further studied Combined with the experimentally measured electromagnetic field distribution,the reliability of the simulation results is proven,and circuit board improvement measures are given.If there are three-phase circuits in the circuit board,the optimization method of increasing the top layer area will be difficult to suppress electromagnetic radiation.The effect of increasing the ground layer will be more obvious;but if there is only one phase circuit in the circuit board,it is preferred to increase the top layer area.