An important trend in the design and test evaluation of electromagnetic compatibility in automobiles in the future

In today's increasingly complex automotive electromagnetic environment, the electromagnetic compatibility issue of complete vehicle EMC has attracted the attention of various countries, relevant industry associations, and major automotive host manufacturers around the world. They have continuously focused on automotive EMC and developed national mandatory standards, industry recommended standards, and automotive manufacturers' own engineering standards. This article will focus on the entire vehicle EMC. In the future, it will also introduce the content of the automotive component level. How EMC designs, tests, and rectifications.

EMC Concepts

EMC (Electro Magnetic Compatibility) refers to the ability of electronic, electrical equipment, or systems to operate normally under expected electromagnetic environments and design requirements. It mainly includes EMI (Electro Magnetic Interference) and EMS (Electro Magnetic Immunity) evaluation systems.

The importance of complete vehicle EMC

In the early 20th century, in the era of traditional internal combustion engine vehicles, there were fewer automotive electronic devices, mainly studying the impact of automotive engine ignition systems and traditional 12th century V power supply systems on electromagnetic radiation interference (EMI) of radio equipment and electronic control units around vehicles.

However, with the development of automotive electrification, intelligence, and networking, as well as the wide application of automotive wireless communication system technology, the compatibility of automotive electronic systems with external complex electromagnetic environments will become an important trend in the design, testing, and evaluation of automotive electromagnetic compatibility in the future. In particular, it is particularly important to study the electromagnetic interference (EMS) solutions of external electromagnetic environments and automotive electromagnetic radiation sources on automotive internal and external electronic control systems. For example, models with advanced automatic driving assistance capabilities will become a top priority in the development of automotive electromagnetic compatibility in the coming years.

Vehicle EMC Challenges

1.The integration of high-voltage components will bring more serious electromagnetic interference, and the electromagnetic compatibility design of high-voltage components will face greater challenges. Challenges include high electromagnetic interference intensity and complex coupling paths.

2. Challenges brought by highly integrated circuits. High voltage components using SOC chips have many advantages, but higher switching frequencies (du/dt, di/dt) bring stronger electromagnetic conduction and radiated interference, posing greater challenges to electromagnetic compatibility.

3. Expanding vehicle intelligence and network functions, conducting comprehensive and accurate simulations of various operating conditions, and detecting EMC issues have brought new challenges. The continuous expansion of vehicle communication frequencies to high-frequency fields, such as LTE communication, 5G/V2X communication, and radar communication, all pose higher requirements for our vehicle design and testing.

4. EMC testing and rectification both involve system level improvements, with long improvement cycles and high costs, which have brought significant cost pressure to vehicle companies.

Main design prevention, test verification, and improvement measures for vehicle EMC

1.The advancement of software simulation technology provides a new idea of introducing EMC analysis into the early design of high-voltage and high-frequency components, and optimizing EMC design from the "source".

2. Harness wiring and grounding, signal cables away from high-voltage networks and strong interference sources, shielded cables transmitting important control communication signals, and 360 ° overlap processing of the shielding layer.

3. Good structural design. EMC structural design should try to avoid common mode interference currents flowing through sensitive circuits or high impedance grounding paths. Structural design should avoid additional capacitive or inductive coupling. Structural design should pay attention to good low impedance interference emission paths.

4. Constantly introduce test simulation equipment in new fields. It is difficult to make many of the sensors that stimulate the vehicle under simulated operating conditions closer to real operating conditions without implementing test disturbances or receiving radiation from vehicle components.

5. The application of magnetic rings and filters adopts active electromagnetic compatibility technology, such as Active EMI Filter (AEF), inductively induced common mode noise, and injected inductance to suppress noise, reducing the volume, weight, and cost of the filter.