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Comparative study on electromagnetic compatibility Test Standards for electric vehicles at home and abroad


       0 Preface

  Electric vehicles refer to vehicles powered by on-board power supplies and driven by motors, including fuel cell vehicles (FCV), hybrid electric vehicles (HEV) and pure electric vehicles (EV). Compared with traditional fuel vehicles, electric vehicles have great differences in power sources, drive systems, and control systems. The power electronic conversion devices equipped on electric vehicles are far more than traditional vehicles in terms of quantity and power. Since electric vehicles use more high-voltage, high-power electrical components and electronic control units with high system integration and electromagnetic sensitivity, the electromagnetic compatibility (EMC) problem of electric vehicles is particularly prominent. Therefore, the severity and complexity of electromagnetic compatibility problems generated by electric vehicles are much higher than those of traditional vehicles.

  The electromagnetic compatibility problem of electric vehicles will not only affect the radio equipment around the vehicle, but also affect the reliability of the electronic components on the vehicle through conduction or radiation, which is directly related to the driving safety of the vehicle. It can be seen that the electromagnetic compatibility problem of electric vehicles is more important than that of traditional vehicles, and the research on electromagnetic compatibility testing and standard system of electric vehicles is the method and way to solve this problem.

  1 Electromagnetic Compatibility Test Standards for Electric Vehicles at Home and Abroad

  1.1 Classification of Electric Vehicle Electromagnetic Compatibility Test Standards

  In terms of electromagnetic compatibility testing of electric vehicles, according to the project, electromagnetic disturbance can be divided into: radio disturbance characteristic test, electromagnetic field strength test and radiation emission test received by vehicle antenna; in terms of electromagnetic anti-interference, it can be divided into vehicle Radiation immunity test of external radiation source, radiation immunity test of vehicle radiation source, high current injection test, electrostatic discharge immunity test and magnetic field immunity test. Table 1 shows the main test standards for EMC of motor vehicles.

Table 1 Main vehicle EMC test standards

 

  In terms of auto parts testing, commonly used test methods can usually be divided into: radio disturbance characteristics test, conduction disturbance characteristics test and conduction transient emission test; in terms of electromagnetic immunity, it can be divided into: radiation immunity test, Immunity Test, High Current Injection Test, Electrostatic Discharge Immunity Test, and Magnetic Field Immunity Test. The main standards for EMC testing of auto parts are shown in Table 2.  

Table 2 Main test standards for EMC of auto parts

  

  1.2 Development direction of electric vehicle electromagnetic compatibility test standards

       In recent years, there have been new developments in the electromagnetic compatibility testing of electric vehicles, and the development of foreign electromagnetic compatibility testing standards is very rapid. In the past two years, new electric vehicle electromagnetic compatibility test standards have been released successively abroad, including ECE R10.04 and SAE J551-52012.

  1.2.1 ECE R10.04

  ECE R10.04 "Unified Regulations on the Approval of Electromagnetic Compatibility of Vehicles" is a certification regulation of the European Union. The introduction of this regulation replaces the version of ECE R10.03.

  Compared with R10.03, ECE R10.04 mainly adds the assessment content for electric vehicles. It mainly adds related detection methods when charging electric vehicles, including:

  (1) AC and DC power line harmonic emission test;

  (2) Radiated emission test of voltage change, fluctuation and flicker on the AC power line;

  (3) AC and DC power line radio frequency band conduction interference test;

  (4) Conducted interference test of the radio frequency band emitted by the vehicle communication and network interface;

  (5) Conducted transient anti-interference test on AC and DC power lines;

  (6) Surge anti-interference test on AC and DC power lines.

  These tests will effectively measure the interference of the electric vehicle to the grid and the anti-interference ability of the electric vehicle when it is disturbed by the grid when the electric vehicle is charging, and ensure the electromagnetic compatibility of the electric vehicle and other electrical appliances on the power network. This will be an important direction for the development of EMC standards for electric vehicles in the future. More and more experiments and research will develop in this direction, and the relevant testing methods and testing standards will be gradually improved and perfected.

  1.2.2 SAE J551-5:2012 Edition

  SAE J551-5:2012 Edition "Measurement Method and Execution Level of Electromagnetic Field Strength of Electric Vehicles, 150kHz~30MHz" is an electric vehicle electromagnetic compatibility test standard launched by the American Society of Automotive Engineers. The introduction of this standard replaces SAE J551-5: 2004 version.

  Compared with the 2004 version, SAE J551-5:2012 version has undergone major changes. According to the development of electric vehicles and with the support of a large number of test data, it further regulates the measurement of the electromagnetic field emission intensity of electric vehicles, and proposes a new detection method, in order to promote the continuous development and improvement of electric vehicle electromagnetic compatibility technology.

  The main revisions of the 2012 version of the SAE J551-5 standard are the reduction of the frequency range in the radiated emission test, the change of the limit line, and the clearer requirements for the conducted emission measurement.

  The main changes in the standard are the following 6 points.

  (1) The frequency range is reduced from the original 0.009-30MHz to 0.15-30MHz, as shown in Table 3.

  Table 3 Comparison of radiated emission test frequency range between SAE J551-5 2004 edition and 2012 edition

  

  (2) SAE J551-5:2004 and SAE J551-5:2012 radiated emission limits have changed. Table 4 is a comparison table of electric field peak limit values.

  Table 4 Comparison of SAE J551-5:2004 and 2012 edition radiated emission electric field test limits (peak limit)

  

  Table 5 is a comparison table of the average limit value of the electric field.

  Table 5 Comparison table of SAE J551-5:2004 and 2012 version radiated emission electric field test limits (average limit)  

  The comparison of the emission limits of electric field radiation is shown in Figure 1.

  Figure 1 Comparison of SAEJ551-5: 2004 and 2012 versions of electric field radiation emission test limits

       For magnetic field testing, only peak detectors are used for measurement.

  Table 6 is a comparison table of magnetic field peak limit values.  

Table 6 Comparison table of SAEJ551-5:2004 and 2012 version radiated emission magnetic field test limits (peak limit)  

  The comparison of emission limits for magnetic field radiation is shown in Figure 2.

  Figure 2 Comparison of SAE J551-5:2004 and 2012 versions of magnetic field radiation emission test limits

  (3) In Appendix A, the formula for the near-field boundary is revised again. The new formula is quoted from the calculation method in ANSI C63.12.

  (4) The vertical polarization measurement of the magnetic field is deleted in the new version of the standard. The main reason is that the field radiation effect of the magnetic field in this polarization direction is poor, so the measured value in this direction is usually lower than that of the other two polarization directions, and it is also very difficult to use this polarization magnetic field as a receiving system component. few. So this polarization direction is removed in the new version.

  (5) Add the measurement limit of the average detector to the limit of electric field strength. Because with the innovation of automobile drive motor technology, the electric field limit value proposed in 1983 can no longer fully examine the electromagnetic radiation characteristics of existing motors.

  (6) The test procedure for maximum radiated emission has been changed. From the original three constant speeds to the three test states of braking, climbing, and cruising in the new version of the standard. It can be said that the new vehicle test state better complies with the radiation emission characteristics of electric vehicles, and can more effectively reflect the true value of radiation emissions of electric vehicles. All in all, the SAE J551-5:2012 version is more in line with the electromagnetic characteristics of the electric vehicle drive system than the 2004 version. In the new version of the standard, this development and change is reflected in the two aspects of the electric vehicle electromagnetic compatibility test method and the state of the test vehicle. This development makes the electromagnetic compatibility test standards of electric vehicles and traditional vehicles more and more different. Such development will be more conducive to the accurate evaluation of the electromagnetic compatibility performance of electric vehicles and play a role in promoting the development of electric vehicle technology.

  The domestic GB/T 18387 is the test standard for evaluating the emission intensity of low-frequency electromagnetic fields of electric vehicles. However, GB/T 18387-2008 borrowed and translated SAE J551-5:2004 as the domestic electric vehicle electromagnetic compatibility test standard. This phenomenon shows that domestic basic research in the field of electric vehicle electromagnetic compatibility test is still relatively weak .

  2 Comparison and analysis of domestic and foreign electric vehicle electromagnetic compatibility test standards

  2.1 Vehicle Test Standards

  Certain EMC test standards for traditional vehicles also describe test methods for electric vehicles. In addition, there are electromagnetic compatibility test standards specifically for electric vehicles. The EMC test standards for electric vehicles at home and abroad are shown in Table 7.

  Table 7 Domestic and foreign electric vehicle electromagnetic compatibility test standards

  It can be seen from Table 7 that two domestic standardization technical committees have formulated domestic electric vehicle electromagnetic compatibility test standards on the basis of referring to international standards. The research and revision capabilities of domestic electric vehicle electromagnetic compatibility test standards are relatively weak.

  2.2 Test Standards for Components

  At present, there is no electromagnetic compatibility test and evaluation system specifically for electric vehicle components at home and abroad. In the actual test, the EMC test evaluation method and test standard of the electric vehicle drive system still refer to the EMC test standard of traditional auto parts. The EMC test standards for auto parts at home and abroad are shown in Table 8.

Table 8 EMC test standards for components at home and abroad

  This paper believes that the reasons for the lack of EMC testing standards and evaluation systems for electric vehicle drive systems are as follows.

  (1) The electromagnetic compatibility test standards and evaluation system for traditional auto parts are very comprehensive. Since the electric vehicle drive system is ultimately installed on the vehicle and connected to the power supply network of the vehicle body, the EMC test of the drive system must also pass the EMC test standards and assessment methods of traditional auto parts to ensure the overall performance after loading. Vehicle electromagnetic compatibility performance.

  (2) The technologies and designs of electric vehicles used by different vehicle manufacturers are quite different. At present, there is no relatively unified technical solution and clear technical route. Therefore, the conditions for the formulation of EMC standards at the component level are not yet mature, and a unified EMC test standard and method cannot be formed. At this stage, major automobile manufacturers are doing electromagnetic compatibility testing of their own electric vehicle drive systems. These component-level electromagnetic compatibility tests are only applicable to the technical solutions formulated by their own companies. On the premise of ensuring the EMC performance of the whole vehicle, automobile companies explore the EMC testing methods of parts.

  (3) The EMC test equipment and infrastructure of the electric vehicle drive system have not been fully standardized, nor have unified technical indicators and requirements. Although some suppliers have launched EMC test equipment solutions for drive motor systems such as e-Chamber, after all, only a few sets have been sold worldwide. It can only be said that the EMC testing equipment for related components of the electric vehicle drive system is still in the development stage, and there is still some way to go before it can be fully adopted by the market.

  3 Conclusion

  Regardless of whether it is on the key components such as the complete vehicle or the drive system, the domestic electric vehicle electromagnetic compatibility test standards are not perfect enough, and the research and formulation of the standards are still in the stage of referring to and translating international standards. The imperfection of the domestic electric vehicle electromagnetic compatibility test standard system will inevitably affect the development of the entire country's electric vehicle industry, seriously restricting the pace of domestic electric vehicle technology development, and will also be restricted by the technical barriers of developed countries when electric vehicles are exported, resulting in Domestic electric vehicle products are at a disadvantage in international competition.

  There are three suggestions for improving the EMC test standards for electric vehicles in my country:

  (1) Extensively study and understand foreign electric vehicle electromagnetic compatibility test standards for digestion and absorption;

  (2) Enrich and accumulate a large amount of electric vehicle electromagnetic compatibility test data;

  (3) Based on the development and innovation of electric vehicle technology at home and abroad, relying on the combination of industry, education and research, to promote the continuous improvement of electric vehicle electromagnetic compatibility test standards and evaluation systems.

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