Research On Electromagnetic Shielding Measures And Shielding Effectiveness Testing Of Vehicle Electronic Device

Large-scale integrated circuits and microelectronic control technology havebrought epoch-making changes to the vehicle control system. They have been widelyused in automotive engine control, chassis control, body control, fault diagnosis, aswell as audio, communications, navigation and other aspects. At the same time, theelectromagnetic environment becomes increasingly complex, the impact betweenelectronic equipments is very serious. Electromagnetic shielding is a main means tosolve the problem, so the study of electromagnetic shielding technology is veryimportant to improve the safety of the car.In this essay, we took a car as the research object and designed systematicelectromagnetic shielding ways for automobile electronic devices. The measures werepartly realized on the objected car. In order to evaluate the shielding effectiveness ofshielding measures, we built a shielding effectiveness test system and researched thesmall bounded wave simulator in the system. Finally we realized the test of shieldingeffectiveness of cables and metal shell and determined test method of shieldingeffectiveness under the system.In order to curb the electromagnetic interference of the coupling, we designedelectromagnetic shielding measures of the car engine system, shell and instrumentsystem. Because there are windows, holes, cable and plastic shell structure in theabove system, we choosed shielding material which is soft and has light-admittingquality, high conductivity quality and permeability. We formulated combinatedshielding schemes in which we can use various shielding materials. We proved thevalidity of shielding measures through the <ISO1145vehicle radiation perturbationresestance test> in the dark waves room on the shielded car.We designed and built a shielding effectiveness test system in which a smallbounded wave simulator act as the core to evaluate shielding effectiveness of carsubsystem and electronic components. The system consists of a bounded wavesimulator system and a pulsed fiber test system. Bounded wave simulator test systemis a self-development system.The shielding effectiveness test system can produce plane electromagnetic waveand the signal waveform conforms to requirements of <GB/T17626.4electromagnetic compatibility tests and testing technology-resistance to flexibility of electric fast transient pulse group test>standard. We can use this system to doshielding effectiveness test to cable less than one meter in length and metal shieldingbody of which the volume is less than one third of the volume of the simulator, thehight is no more than five eighths of the simulator.The main contributions of this paper are:(1) Designed electromagnetic shielding measures for the car engine system,instrument system and car shell with the existing shielding techniques. Combinedwith car structure characteristics, we have designed combinated shielding schemes forvarious shielding materials. The experiments results show that the methods aboveeffectively improved the car’s anti-electromagnetism interference ability.(2) Built shielding effectiveness test systems and realized shieldingeffectiveness tests of the cable and metal shell. The bounded wave simulator system isthe core part of the shielding effectiveness test system. The waveform of the boundedwave simulator system is double exponential pulse, its maximum peak isapproximately18kV/m and test frequency is100MHz. It can satisfy the basic needsof shielding effectiveness test of cables, electronic equipments and subsystem.The above works explored systematic application methods and shieldingeffectiveness test methods of the existing shielding techniques in automotiveelectronics equipment electromagnetic protection and provided the certain referencevalue for automobile electronic equipment’s anti-electromagnetism interferencedesign and project implementation.