GB/Z 21437.4-2025Road vehicles - Test method of electrical disturbances from conduction and coupling - Part 4: Electrical transient conduction along shielded high voltage supply lines only (English PDF)

4.1 General Provisions

During the switching process of various devices in the vehicle, various transient waveforms will be generated on the high voltage supply lines. Among them, pulse A is a ringing wave generated by the switching operation of a high voltage semiconductor device, and pulse B is a sine wave generated by the rotation of a motor (such as a drive motor) and the harmonics of the high voltage network.

The transient emission measurement method of shielded high voltage supply lines and the transient immunity test method of the device involved in this document are all bench tests conducted in the laboratory.

Bench test methods can provide comparable and repeatable test results between laboratories.

These methods can also be used as a basis for testing equipment and systems during the R&D and production stages.

Use bench testing to evaluate the supply line transient immunity of a device under test (DUT).

Bench testing can be achieved using a pulse generator approach, where the test pulses described are only typical pulse forms and do not cover the various transients that may occur on the vehicle.

In special cases, it may be necessary to apply additional test pulses. Certain test pulses may also be ignored if a device is not affected by similar transients in the vehicle due to its function or connection. It is the vehicle manufacturer's responsibility to define the type of test pulses required for a particular DUT.

Disturbances include the following two types.

--- Pulsed sinusoidal disturbance (pulse A);

--- Low frequency sinusoidal disturbance (pulse B).

Pulsed sinusoidal disturbances on high voltage supply lines are caused by square wave signal overshoot, such as the interaction between the on and off of insulated gate bipolar transistors (IGBTs) in high voltage systems and the parasitic capacitance and inductance of motor systems, DC-DC converters and other types of high voltage switching/commutating systems. Pulsed sinusoidal disturbance on high voltage supply lines can be either common-mode disturbance [line-to-ground (HV+ or/and HV- to ground)] or differential-mode disturbance [line-to-line (HV+ to HV-)].

Test pulse A is used to test the DUT's ability to withstand high frequency oscillations, such as rapid on-off of switches.

Test pulse B is used to test the DUT's ability to withstand transient voltages.

The DUT shall work under the typical operating conditions that generate the greatest disturbance and are the most sensitive, so that the DUT is in the worst working condition for each test and each frequency step. Typical operating conditions for the DUT shall be negotiated between the vehicle manufacturer and the supplier and documented in the test plan.

4.2 Standard Test Conditions

The test temperature and low-voltage power supply voltage of the DUT shall use the standard test conditions specified in GB/T 21437.1.

The high voltage supply voltage UN ranges from 60 V (DC) to 1 500 V (DC). The voltage of the battery/high voltage power supply used for DUT operation and its tolerances shall be negotiated between the vehicle manufacturer and the supplier and documented in the test plan.

4.3 Grounding Plate

The grounding plate shall be made of copper, brass or galvanized steel at least 0.5 mm thick.

Unless otherwise specified in the test plan, the minimum width of the grounding plate shall be 1 000 mm, or 200 mm greater on either side of the entire measurement setup area (excluding power supplies and transient pulse generators), whichever is greater.

Unless otherwise specified in the test plan, the minimum length of the grounding plate shall be 2 000 mm, or 200 mm greater on either side of the entire measurement setup area (excluding power supplies and transient pulse generators), whichever is greater.

4.4 General Test Setup Conditions

The DUT shall be arranged and connected according to its requirements. Unless otherwise specified by the vehicle manufacturer and supplier, the DUT shall be connected to the actual vehicle working devices (loads, sensors, etc.), and the test setup described in Sections 4.5.2, 4.6.2.1 and 4.6.3.1 shall be used.

If there is no signal source for the DUT to actually work from, an analog signal source can be used instead.

Unless otherwise specified in the test plan, all loads, sensors, and grounds (ground wire, grounded metal enclosure) shall be connected to the grounding plate.

To minimize additional capacitive coupling to the DUT, the distance between the DUT and all other conductive structures should be greater than 0.5 m. Conductive structures include the walls of the shielded room, etc. (except for the grounding plate underneath the test setup).

4.5.1 Overview of test methods

DUTs with potential sources of conducted disturbances shall be tested in accordance with the procedures described in this clause.

Transients shall be measured between HV+ and HV- (line-to-line) and between HV+ and ground and HV- and ground (line-to-ground) respectively.

It shall be ensured that the measurement setup is free from interference from the surrounding electromagnetic environment.

4.5.2 Test setup

When measuring the voltage transient emissions of a DUT, a high voltage artificial network (HV-AN) shall be used to regulate the impedance load of the DUT (see Section 5.1). The DUT is connected to the high voltage power supply through an artificial network (see Section 5.2), as shown in Figure 1.

Unless otherwise specified in the test plan, the length of high voltage supply lines shall be 500 (+200/-0) mm. The length of the harness used shall be recorded in the test report.

The grounding of DUT shall be connected to a grounding plate. Unless otherwise specified in the test plan, the default length of the ground wire is (200±50) mm. If the DUT has a metal enclosure, the enclosure shall be bonded to a grounding plate. The DC resistance of the ground connection shall not exceed 2.5 mohm.

The DUT shall be placed on the grounding plate in a manner consistent with the vehicle application. Unless otherwise specified, the DUT and all connecting lines between the artificial network and the DUT shall be placed on a non-conductive material with low relative permittivity (epsilonr<=1.4) at (50±5) mm above the grounding plate.

The supply voltage UN and disturbance voltage shall be measured near the DUT power supply terminals using a voltage probe and an oscilloscope or waveform acquisition device (see Figure 1).