GB/T 38775.4-2020Electric vehicle wireless power transfer—Part 4: Limits and test methods of electromagnetic environment (English PDF)

3.1 Occupational Exposure

Occupational exposure refers to all electromagnetic field exposure that individuals are subject to due to the engagement in fixed or designated occupational activities. Under the conditions of receiving appropriate instructions and trainings, workers are already informed, and voluntarily experience the effects of the electromagnetic fields.

3.3 Medical Exposure

Medical exposure refers to electromagnetic field exposure to patients undergoing medical diagnosis or approved medical treatment, or volunteers in medical researches.

3.4 Active Implantable Medical Device

Active implantable medical device refers to active medical devices implanted in the human body.

3.5 Touch Current

Touch current refers to the current flowing through the human body or animal when they touch one of more accessible parts of devices or equipment.

3.6 Basic Restriction

Basic restriction refers to a limit determined for human tissue that may cause harmful health effects. It strictly conforms to all the already-known biophysical interaction mechanisms and is usually difficult to measure.

3.7 Reference Level

Reference level refers to a physical quantity introduced for the convenience of actual exposure assessment that are convenient for actual measurement.

4.1 Protection Areas

The following four protection areas are defined, see Figure 1.

4.2 Limit Compliance Requirements

Comply with the following limit compliance requirements.

5.1 Electromagnetic Field Limits

5.1.1 Human exposure limits

Electromagnetic field limits of human exposure include basic limits and reference levels, which are respectively shown in Table 1 and Table 2. The compliance with the reference levels in Table 2 can ensure the compliance with the basic limits in Table 1.

5.1.2 Exposure limits of active implantable medical devices

In this Chapter, the corresponding frequency band of the limit requirements is. 79 kHz ~ 90 kHz.

5.2 Contact Current Limits

Contact current limits are shown in Table 4.

6.1 Test Conditions

6.1.1 Temperature, humidity and atmospheric pressure

The environmental requirements of the laboratory are as follows. °C

6.1.2 Test point

Within a 1.5 m horizontal range around the test point, there shall be no objects that would affect the test. Primary devices shall be placed on non-metallic ground.

The environmental background value shall be not higher than 5% of the limit value in Chapter 5.

6.2 Test Instruments

6.2.1 Test instruments of magnetic field

A three-axis isotropic low-frequency field strength probe shall be used. In addition, the circular sensor area shall be not more than 100 cm².The probe shall use peak detection.

6.2.2 Test instruments of contact current

6.2.2.1 Overview

Test instrument is constituted of test impedance network and test electrodes. The bandwidth should be more than 100 MHz.

6.2.2.2 Test impedance network

The perceptual or reactive current test impedance network shown in Figure 2 shall be used for testing.

6.2.2.3 Test electrodes

Unless it is otherwise specified in the test instrument standard, the test electrodes shall be one of the following two modes.

6.4 Test Method of Magnetic Field

6.4.1 Test range

Conduct electromagnetic field test for Protection Area 3, Protection Area 4 and off-board power components.

The electromagnetic test shall be conducted in four test areas. the front, the rear, the left and the right of the vehicle.

Before the test, open the door; adjust the seat to the middle position, as it is shown in Figure 5. If the seat cannot be adjusted to this position, then, in accordance with the seat position declared by the manufacturer, adjust the seat.

6.4.2 Test point of Protection Area 3

6.4.3 Test point of Protection Area 4

7.1 Electromagnetic Field Test Result Evaluation

In terms of four test areas. Protection Area 3a, Protection Area 3b, Protection Area 4 and off-board power components, respectively evaluate the electromagnetic field test result. See the evaluation procedure below.

7.2 Contact Current Test Result Evaluation

The evaluation procedure for contact current test result is as follows. […]