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ISO 7637: “Road vehicles — Electrical disturbances from conduction and coupling”
ISO 7637 is the automotive standard that sets out test methods for evaluating conducted immunity at the module level.
ISO 7637 defines test methods for determining how modules react to transient disturbances (conducted immunity).. ISO 7637-1 sets out general principles and can be purchased and downloaded from the ISO. It has four separate parts, with parts 2, 3, and 4 outlining specific test methods. A summary of what is in each part is included below.
For a given electronics module that draws typical 12V power, testing to both ISO 7637-2 and -3 will likely be needed. For units that interface with shielded high voltage power lines in an electric vehicle, ISO 7637-4 will apply. There are a lot of transients associated with operating a car/bus/truck–power surges on startup, transients from large inductive loads (motors) switching on and off, transient interruptions as connections are jostled loose by the bouncing of the car over roads for multiple years, etc. Testing for conducted immunity can be a significant portion of your overall EMC testing schedule.
ISO 7637 shares with ISO 11451 the structure of evaluating unit performance based on a functional performance status classification system, which is useful even outside the automotive industry.
ECE Reg 10: “Uniform provisions concerning the approval of vehicles with regard to electromagnetic compatibility”
ECE Reg 10.06 is a key automotive standard for manufacturers planning to sell vehicles in Europe.
UN/ECE Regulation No. 10 is a key automotive standard for manufacturers planning to sell vehicles in Europe. It is officially on its 6th revision (which can be freely downloaded here) and has been amended twice, most recently in 2022. Revision 7 is currently in work. It is an official publication of the United Nations Economic Commission for Europe. Ultimately a vehicle manufacturer will apply for “type certification” for a given vehicle line to be sold in Europe. In addition to the paperwork, a representative vehicle will need to be tested to ECE Reg 10 in the presence of an official EU witness.
It covers immunity, emissions, and the specific hazards concerning plugin electric vehicles with concern to the power grid. The limits for different tests are found in Appendices 2 - 7. The test method details are found in Annexes 4 - 22. In general, ECE Reg 10 adopts the following international standards:
CISPR 12 for off-board radiated emissions
ISO 11451-2 for off-board radiated immunity
CISPR 25 for radiated emissions from modules
ISO 11452-2, 3, 4 or 5 for radiation immunity of modules
ISO 7637-2 for module-level immunity to transient disturbances
The following apply to plug in electric vehicles in their charging mode only, either at the component or vehicle level:
IEC 61000-3-2 and -12 for measuring the harmonic conducted emissions on the AC power lines
IEC 61000-3-3 and -11 for measuring voltage flicker on AC power lines
CISPR 16-2-1 to measure RF conducted emissions
CISPR 22 to measure RF conducted emissions on wire network port
IEC 61000-4-4 for conducted immunity to fast transient/burst disturbances
IEC 61000-4-5 for conducted immunity to power surges
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Because ECE Reg 10 has detailed test setups for adapting various international EMC standards to its exact automotive concerns, you can learn a lot about EMC standards and testing by reading through this freely available document.
ISO 11451: “Road vehicles — Vehicle test methods for electrical disturbances from narrowband radiated electromagnetic energy”
ISO 11451 is a collection of test methods addressing vehicle level immunity to electric fields.
ISO 11451 is a collection of documents that describe automotive test methods for testing at the vehicle level to show immunity to various levels of electromagnetic environment. You can purchase 11451-1 here, and the same site has the other parts available as well. The parts are all revised on their own schedules, with Part 1 (current version published in 2015) expected to have a new revision published in 2024.
ISO 11451 is applicable to any kind of passenger car or commercial vehicle, whether traditional internal combustion engine or electric. Its test methods cover the frequency range 10 kHz - 18 GHz, but it is more often applied within a narrower range, such as 1 MHz - 2 GHz. Table 1 lists the different test methods available.
*LUF = lowest usable frequency of a particular reverb chamber.
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Remember that the plane wave illumination at each frequency in ISO 11451 testing isn’t a constant continuous wave. Different modulations are applied to different frequency ranges to better capture real world threats.
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ISO 11451 defines a set of functional performance status classifications (seen below). Widely used in the automotive industry, these categories can be helpful in defining the success criteria for immunity/susceptibility testing for many complex systems, either at the platform or module level. When a device under test has many functions, some of them may be more critical than others. For instance, if the infotainment system gets knocked offline, that’s inconvenient for the user, and the manufacturer may want to address the issue if it happens at too low of a field strength, such that it might happen often. On the other hand, if the headlights can get turned off by any of the test exposures, that would be a major safety concern that would have to be addressed. Combining the criticality of different functions with the performance status classifications from ISO 11451 in a test plan can be a good way to predetermine which “failures” or “anomalies” are acceptable and which must be labeled failures and fixed. It’s a more detailed framework than the “must function normally” criteria found within some immunity/susceptibility test plans.
CISPR 36: “Electric and hybrid electric road vehicles - Radio disturbance characteristics - Limits and methods of measurement for the protection of off-board receivers below 30 MHz”
CISPR 36 is specific to electric vehicles and covers low frequency magnetic fields, 150 kHz - 30 MHz.
CISPR 36 is a relatively new standard, with its first official release in 2020. You can purchase a copy here. While it is strongly influenced by an earlier Chinese standard, GB/T 18387, CISPR 36 has a narrower frequency range, starting at 150 kHz instead of 9 kHz. It stops at 30 MHz, which is where CISPR 12 picks up.
CISPR 36 is unusual in focusing on low frequency magnetic fields, although its purpose is still to protect the radio reception of receivers outside the vehicle. On board receivers are protected by CISPR 25, same as any other vehicle. CISPR 36 only applies to ground vehicles with electric motors that draw power from a traction battery with voltage between 100 and 1000 V.
CISPR 36 uses magnetic field (loop) antennas positioned 3 m away from the vehicle. Measurements are taken with the vehicle at speed (on a dynamometer) at four positions (in front, behind, and to either side of the vehicle) and two orientations, for a total of eight sweeps. The sweeps are from 150 kHz - 30 MHz with a resolution bandwidth of 9 kHz. The limits are the magnetic field strength in dBuA/m, taken as a quasi peak (QP) measurement. In general most test operators will sweep in peak detection mode first, and only return to take QP measurements at specific frequencies where the peak value is above the QP limit. (See our explainer on quasi peak measurements.) Measurements can be taken in a semianechoic chamber or properly characterized open air test site, not in a reverb chamber.
Right now CISPR 36 does not address the charging mode, either via plug in or wireless power transfer (WPT). Other committees are looking into those modes, and ANSI C63.30 was published in 2021 describing test methods for WPT specifically.
ISO 11452: “Road vehicles — Component test methods for electrical disturbances from narrowband radiated electromagnetic energy”
ISO 11452 is a standard with multiple parts and test methods that covers testing components that will go on vehicles (cars, trucks, etc.) for immunity.
ISO 11452 covers automotive components for immunity testing--with, as we see with several other standards, a whole lot of parts that can be bought separately. You can see which parts cover which test methods in the tables below. You can start by looking at ISO 11452-1 (“General principles and terminology”) which is available for purchase here. The current version is from 2015 and a new revision is expected in the next year or so.
ISO 11452 uses CISPR 16 to govern the measurements equipment used. Annex A of ISO 11452-1 has a very useful normative guide on how to classify the performance of different functions during testing (you would not call a test a failure if an infotainment system spontaneously reset during moderate level testing; the brake system doing the same thing would be considered a critical failure).
You might notice similarities between ISO 11452 and its various parts and those of SAE J1113. That’s not a coincidence--J1113 was essentially the North American version of the same document until they came into agreement.
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If you have the facility available, testing in a reverb chamber (ISO 11452-11) is often the fastest way to test and also the one most likely to find problems. That sounds like a bad thing, but it’s much better to find problems when it’s one component in a chamber instead of troubleshooting an entire vehicle.