Automotive Electrical Equipment Electromagnetic Compatibility Testing

Reference Standards: GB/T 18655-2018, GB/T 33014.2-2016

I. Introduction

The Electromagnetic Compatibility Laboratory of Beijing Yizong Institute conducts electromagnetic compatibility (EMC) testing for automotive electrical equipment in accordance with national standards GB/T 18655-2018 and GB/T 33014.2-2016. The tests cover conducted emissions, radiated emissions, and immunity tests, aiming to ensure the compatibility of vehicle electronic equipment with receivers and verify their reliability in electromagnetic environments.

II. Overview of Test Standards

1. GB/T 18655-2018
• Scope: Applicable to electronic/electrical components of vehicles, ships, and internal combustion engines, covering a frequency range of 150 kHz to 2500 MHz. It includes conducted emission and radiated emission tests to protect vehicle receivers from electromagnetic interference.
• Core Content:
• Conducted Emissions (Voltage Method, Current Probe Method);
• Radiated Emissions (ALSE Method, Stripline Method);
• Limits Classification for Vehicles and Components (Class 1–5, commonly Class 3–5).
2. GB/T 33014.2-2016
• Scope: Focuses on narrowband radiated electromagnetic immunity testing for electrical/electronic components of road vehicles, using the anechoic chamber method with a frequency range of 80 MHz to 6 GHz.
• Core Content:
• Simulates external electromagnetic field interference on equipment;
• Severity level classification (Appendix C recommended levels);
• Test setup must comply with anechoic chamber background noise and uniform field requirements.

III. Test Items and Methods

(1) Conducted Emission Test (According to GB/T 18655-2018)

1. Test Purpose
• Evaluate continuous disturbance levels at power ports and signal cables to prevent interference from coupling to vehicle receivers via wiring harnesses.
2. Test Methods
• Voltage Method: Measures conducted emissions at power ports; artificial network (AN) isolates grid interference, with a ground plane size of ≥1000 mm × 400 mm.
• Current Probe Method: Detects conducted disturbances at signal ports, with a ground plane size of ≥2500 mm × 400 mm.
3. Equipment Configuration
• Artificial Network (AN), current probe, receiver, reference ground plane.

(2) Radiated Emission Test (ALSE Method, According to GB/T 18655-2018)

1. Test Purpose
• Evaluate electromagnetic disturbances radiated by the equipment to ensure they do not affect vehicle antenna reception performance.
2. Test Method
• Uses an anechoic chamber (ALSE) with a wiring harness length of 1.7–2 m, equipped with an artificial network to isolate power interference.
• Antenna Configuration:
• 150 kHz–30 MHz: Monopole vertical antenna;
• 30–200 MHz: Biconical antenna;
• 200 MHz–1 GHz: Log-periodic antenna;
• 1–2.5 GHz: Horn antenna or log-periodic antenna.
• Both horizontal and vertical polarizations must be tested.
3. Limit Standards
• Judged according to Class 3–5 levels; frequency band limits must be negotiated with the vehicle manufacturer.

(3) Narrowband Radiated Electromagnetic Immunity Test (Anechoic Chamber Method, According to GB/T 33014.2-2016)

1. Test Purpose
• Verify the functional stability of equipment under narrowband electromagnetic field interference.
2. Test Method
• In an anechoic chamber, continuous narrowband signals in the range of 80 MHz to 18 GHz are transmitted via an antenna to simulate external electromagnetic environments.
• Key Parameters:
• Severity Level: Selected according to Appendix C (e.g., field strength levels L1–L3);
• Modulation: AM 80% or CW;
• Dwell Time: ≥2 seconds per frequency point.
3. Judgment Criteria
• The equipment must maintain normal functionality during testing, without performance degradation or malfunction.

(4) Other Immunity Tests (Supplementary Items)

1. Bulk Current Injection (BCI)
• Injects interference signals into wiring harnesses via a current probe to evaluate equipment immunity to conducted interference.
2. Transient Immunity Test (TCS-P)
• Simulates transient pulses on power lines (e.g., load dump, inductive load disconnection) to detect equipment immunity to transient interference.
3. Electrostatic Discharge Immunity Test
• Assesses equipment tolerance to electrostatic discharge (ESD) according to ISO 10605 or GB/T 19951.

IV. Test Equipment and Configuration

1. Core Equipment
• Anechoic chamber (compliant with CISPR 25 requirements), artificial network, receiver (covering 150 kHz–2.5 GHz), signal generator (80 MHz–18 GHz), current probe, electrostatic discharge simulator.
2. Auxiliary Facilities
• Shielded room, load simulator, wiring harness layout platform, temperature control system (meeting GB/T 33014.1 test conditions).

V. Test Process

1. Pretreatment: Power on the equipment for warm-up; arrange wiring harnesses according to the vehicle's original layout.
2. Baseline Test: Record equipment performance parameters in an interference-free state.
3. Interference Application: Gradually increase field strength or current as required by the standard.
4. Function Monitoring: Monitor equipment functional status in real-time and record failure thresholds.
5. Data Analysis: Compare with limits and generate a test report.

VI. Test Report Content

• Equipment information, test standards, test configuration, test data, limit comparison, conclusions, and improvement suggestions.

Note: This outline is formulated based on current national standards. Specific test plans must be adjusted according to vehicle model requirements and manufacturer agreements.
Laboratory Address: No. A397, Guang'anmenwai Street, Xicheng District, Beijing (Yizong Institute Laboratory).