Research On Simulation Of Vehicle Level Electromagnetic Radiated Emission Of Electric Vehicle

Innovations in electronic technology,as the main innovation point in automotive technology,have both improved the overall vehicle performance as well as significantly increased the variety and quantity of automotive electronic devices,further complicating the vehicle electromagnetic environment.Electromagnetic compatibility(EMC)not only concerns the operational reliability of wireless devices around the vehicle,as well as its electronic and electrical parts,but also affects the safety of driving.In the meantime,global automobile industries have begun their transformation toward and upgrading along the direction of new energy vehicles.Compared with the traditional fuel-engine vehicle,electric vehicle features both high-and low-voltage systems,immediately revealing the level of importance EMC plays in the application of electronic technologies in cars.Satisfactory vehicle EMC is largely dependent on design quality.EMC problems discovered after the development of vehicle body structure,parts,electrical system,etc.,may lead to frequent and repeated troubleshooting as well as localization tests due to the difficulty in locating the source of interference.Meanwhile,technical approaches adopted to solve the problems of limit-exceeding parameters are also subject to various restrictions.Even parts that seem to have met the limits for performance indicators such as radiated and conducted emissions does not necessarily mean that the vehicle's EMC has already met the requirements.It is necessary to first simulate and predict the emission of electromagnetic radiation in the entire car,and compare the result with the state-regulated limit,before using it as a guidance torectify the main interference source and coupling routes with the over-the-limit frequencies.Doing so prevents the late detection of incompatibility,especially after the completion of R&D and manufacturing,hence reducing the overall development cycle of the vehicle model and cutting down R&D costs.In such a context,this paper combined with the Key Special Project of the National Key R&D Program(Project No.2017YFB0102500)under Topic No.4: Vehicle EMI Noise Modeling,Prediction,and Suppression Technology,and focused on the following aspects to simulate and predict the electromagnetic radiation emission of electric vehicles:1.The EMC theory and analysis of the electromagnetic environment of electric vehicles.The formation mechanism of electromagnetic interference(EMI)was introduced.Taking an electric vehicle in China as an example,the source of interference and coupling path—two of the three elements of EMC problems—were expounded,followed by analyzing the nature of radiated emission tests.2.The modeling method for the simulation of vehicle electromagnetic radiation emission.Considering the huge volume and complex structure of vehicles,this research referred to the methods used in specific modeling process of actual examples,and employed them to build a simulation model of the target car model's vehicle electromagnetic radiation emission,laying a foundation for the prediction of vehicle electromagnetic radiation emission.3.Simulation and prediction of vehicle electromagnetic radiation as well as model verification.According to the GB/T 18387 standard test conditions,a bench test was performed to obtain the key parameters,based on which the radiation intensities of the electric and magnetic fields outside the vehicle were predicted.By comparing the simulation and prediction results with the measured data,the accuracies and validitiesof the simulation and prediction were verified.Using the simulation and prediction data,the main sources of interference and coupling paths were eventually located,providing guidance for further improvements.4.Design optimization and verification of interference sources and coupling paths.To meet the performance requirements for electric vehicles' overall electromagnetic radiation emission,the EMI coupling paths of the high-voltage systems and the main coupling modes were analyzed to provide related optimization solutions and suggestions.The sources of interference and coupling paths were verified via real-life tests at the end of the rectification,based on which results the target car model was adjusted to comply with the GB/T 18387 standards.The above research proposed a set of effective and engineering-feasible modeling methods for the simulation of vehicle electromagnetic radiation emission,predicted the electromagnetic radiation emission of a specific electric vehicle model,and then verified the simulation model.Based on the simulation results,the problem was identified and solved.Design optimization and experimental verification were then carried out to tailor the target car model and fit its performance with the requirements for electromagnetic radiation emission.