EMC FLEX BLOG A site dedicated to Automotive EMC Testing for Electronic Modules

This test is intended to measure the level of harmonics generated by the DUT in configuration "REESS charging mode coupled to the power grid" through its AC power lines in order to ensure it is compatible with residential, commercial and light industrial environments.

REESS means the rechargeable energy storage system that provides electric energy for electric propulsion of the vehicle

This CE testing must be performed per:

1. IEC 61000-3-2 for input current in charging mode ≤ 16 A per phase;
2. IEC 61000-3-12 for input current in charging mode > 16 A and ≤ 75 A per phase.

The measurements of even and odd current harmonics shall be performed up to the 40th harmonic.
The limits for single phase or three-phase DUTs in configuration "REESS charging mode coupled to the power grid" with input current ≤ 16 A per phase are given in Table 1 below:

The limits for single phase DUTs in configuration "REESS charging mode coupled to the power grid" with input current > 16 A and ≤ 75 A per phase are given in Table 2 below:

The limits for three-phase DUTs in configuration "REESS charging mode coupled to the power grid" with input current > 16 A and ≤ 75 A per phase are given in Table 3 below:

Test Setup and Procedure

• The DUT must be in configuration "REESS charging mode coupled to the power grid".
• The state of charge (SOC) of the traction battery shall be kept between 20 per cent and 80 per cent of the maximum SOC during the whole time duration of the measurement (this may lead to the measurement being split into different time slots with the need to discharge the vehicle’s traction battery before starting the next time slot).
• If the current consumption can be adjusted, then the current shall be set to at least 80 per cent of its nominal value.
• The observation time to be used for the measurements shall be as for quasi-stationary equipment as defined in Table 4 of IEC 61000-3-2.
• The test set-up for single phase DUT in configuration "REESS charging mode coupled to the power grid" is shown in Figure 1 of Appendix 1 to Annex 17, ECE Regulation 10.
• The test set-up for three-phase DUT in configuration "REESS charging mode coupled to the power grid" is shown in Figure 2 of Appendix 1 to Annex 17, ECE Regulation 10.

 The EV does not mean the end of 12V automotive battery. For various safety reasons, complex modules are powered using two 13.5V / 200A batteries such that the Backup battery comes into play the moment the Main battery's voltage is outside operating voltage range.

The Ground Offset Test involves a voltage variation of +/- 1V on Supply Return line that may affect DUT circuitry referenced to an absolute 0V via remote ground. The diagram below shows how to use a combination of three power supplies to simulate the +/- 1V Ground Offset condition.

2022-06-29

Christian Rosu

RF Boundary is the element of an EMC test setup that determines what part of the harness and/or peripherals is included in the RF environment and what is excluded. It may consist of, for example, ANs, BANs, filter feed-through pins, RF absorber coated wire and/or RF shielding.

RF Boundary is also an RF-test-system implementation within which circulating RF currents are confined

• to the intended path between the DUT port(s) under test and the RF-generator output port, in the case of immunity measurements (ISO 11452-2, ISO 11452-4, ISO 1145-9), and

• to the intended path between the DUT port(s) under test and the measuring apparatus input port, in the case of emissions measurement (CISPR 25),

and outside of which stray RF fields are minimized.

The boundary is maintained by insertion of BANs, shielded enclosures, and/or decoupling or filter circuits. The ideal RF boundary replicates the circuitry of the device connected to DUT in vehicle.

The standard test harness lenght for automotive EMC electronic components is (1700mm -0mm / +300mm). This 1.7m test harness runs between the DUT and the Load Simulator (Shielded Enclosure) that plays the role of RF Boundary.

If the Load Simulator enclosure does not include all DUT loads and activation/monitoring support equipment, additional support devices may be placed directly on the ground plane. The connection of additional devices to LS enclosure must be done via short wiring running on the ground plane.

Testing at subsystem level is preferable to any simulation. Whenever possible, use production intent representative loads.

Running long coax cables directly from DUT outside the chamber via SMA bulk filter panel would violate the 1.7m test harness length rule invalidating the test result. Ideally is to use Fiber Optic to exchange data with devices placed outside the test chamber.

Running long coax cables between Load Simulator and a support device placed outside the chamber is acceptable as long as the I/O line in question is not just an extension from DUT without proper RF boundary at the end of maximum 2-meter length of standard test harness.

It is critical to use the test harness length as defined by CISPR-25, ISO 11452-2, ISO 11452-4, and ISO 11452-9 to achieve valid compliance for your product. The length of the test harness as well as the grounding method (remote vs local) can result in different RF emissions level. Longer the test harness, higher RF emissions above 100 MHz due to its resonance pattern. The local grounding would show less magnitude variation across resonance peaks above 100MHz.

Christian Rosu

2022-02-20