Analysis of the impact of automobile electromagnetic compatibility on the application of automotive electronic technology

The application of automotive electronic technology is related to the automotive electromagnetic environment, which is mainly caused by the electromagnetic environment in which the vehicle is located. At the same time, the vehicle's own ability to resist electromagnetic interference is also crucial. In addition to the influence of the external electromagnetic environment on the vehicle, the application of electronic products itself also has a certain ability to resist the influence of the external electromagnetic environment. This is a two-way thing. In addition, the vehicle is a mobile body, so the electromagnetic environment it is in is relatively complex and harsh. Vehicles in different regions also respond differently to electromagnetic interference. For example, ESD is weaker in the south than in the north, and it is particularly obvious in the north in winter.

　　I summarized the electromagnetic environment of vehicles. There are low-frequency conduction and radiation, high-frequency conduction and radiation, and electrostatic discharge. Of course, there are electromagnetic and pulse in the air. There are few reports in China. A few days ago, a cleaner in Beijing was injured by lightning while holding a mobile phone. There are also reports abroad that a vehicle was knocked down by a lightning in an open field. This is lightning. Military vehicles also need to consider the influence of nuclear power, nuclear explosion, and nuclear electromagnetic. This is a complex electromagnetic environment.

　　In a complex electromagnetic environment, it is most obvious that vehicles are better off running on city roads, especially on suburban roads. Some high-voltage wires, some current high-speed railways, and even magnetic levitation do have an impact on the surrounding environment. We have measured how large the magnetic field can be generated under the high-voltage wires, a 600-volt-meter magnetic field. In this environment, do vehicles need to consider the issue of anti-electromagnetic environment?

　　What is electromagnetic compatibility? I have introduced electromagnetic compatibility on many occasions, and everyone is familiar with it when they ask about it, especially when some problems are found in the vehicle, and electromagnetic compatibility is also considered. However, when I understand it, the concept of electromagnetic compatibility is not very clear. The electromagnetic interference of the electromagnetic environment to the equipment or system is objectively present, but in order to ensure the normal operation of the car function, the ability of the car function to resist electromagnetic environment interference must be improved. Electromagnetic environment emission is the result of the joint action of various electromagnetic emission sources. In order to achieve the coordinated balance and coexistence of various electrical equipment, the electromagnetic compatibility level as a parameter is specified between the emission level of various emission sources and the equipment immunity level to achieve electromagnetic compatibility.

　　As far as automobile electromagnetic compatibility is concerned, electromagnetic compatibility is the ability of a vehicle or component or independent technical unit to work satisfactorily in its electromagnetic environment without causing undue electromagnetic disturbance to anything in the environment. In other words, my car is a complex that does not affect the outside world, and at the same time I have a certain resistance to the electromagnetic influence of the outside world. That is to say, in the space around it, within a certain period of time, under the conditions of available spectrum resources, the car itself and the surrounding equipment can coexist without causing degradation. As we all know, space, time and spectrum are indispensable. Everyone said that I have done experiments on electromagnetic compatibility, but why can't I pass it when I install it on the car. Later, I took a look and said that the frequency of your experiment is not the same as the frequency of the vehicle's attention, and they are not in the same frequency band. Therefore, some electromagnetic compatibility experiments now have their limitations. When applying electronic technology, some electromagnetic compatibility experiments should be considered more comprehensively. The following introduces a safety integrity. Because functional safety integrity is accidental and secondary, it is impossible to completely eliminate it. Only by striving to achieve its risk of zero, this is our goal. Therefore, safety integrity is proposed. Under specified conditions and within a specified time, the probability that the safety-related system can achieve the required function is one. This is what we call the safety integrity level. In reality, we have here the failure probability per hour. For example, in the past, a car might fail after being used for 100 hours. Now I have raised it to the level of Level 4, which means that there will be a failure once in 10,000 hours. Now it is basically called a low-risk failure probability. It cannot be said to reach more than 10,000 hours, but it is about the same level as below 10,000 hours to 1,000 hours. Of course, there is now an international reliability evaluation for various models, and the reliability evaluation is relatively high. You can check it out. Generally speaking, it is much better than in the early days.

　　As for our vehicle manufacturers, we must first determine the safety integrity level of our vehicles after they leave the factory. If the vehicle is 100 hours under the low requirements in the early stage, can it be raised to 1,000 hours or 10,000 hours? In the past, there was an evaluation for the vehicle, which was the reliability evaluation. There is such a requirement for the reliability evaluation. We hope that vehicle manufacturers should consider the reliability of their products and vehicle products in the application of new technologies.

　　Another solution for the EMC electromagnetic compatibility of automotive functional safety is to first formulate electromagnetic compatibility specifications, which are generally divided into three levels: the requirements for safe vehicles, the second is the requirements for systems and subsystems, and the third is components. They should be divided into three levels. Secondly, the functions of the vehicle are experimentally verified and determined. The requirements of the three levels of specifications are related to each other. Some parts are made by the vehicle manufacturer, and the vehicle manufacturer has requirements for it. He made one himself, and the vehicle manufacturer formulated another one according to the requirements of the enterprise. They are related to each other, and each component is used in different places, and the requirements are different. For example, the engine, communication, and entertainment system have different requirements. For example, the engine should be part of the general assembly requirements, and the engine should have the highest requirements, while the entertainment system can be relaxed. In this way, you can reversely think about the relationship between your components and subsystems and between the whole vehicle, and the correlation here.

　　Another confirmation is that the parts have an experimental verification confirmation, the system and subsystem also have an experimental verification confirmation, and finally the whole vehicle also needs verification. Some people say that if the parts have passed the experimental verification, there should be no problem in installing them in the whole vehicle, which is not true. Electromagnetic compatibility confirmation must be done on the whole vehicle, and the final confirmation is on the whole vehicle, but if you don’t do the parts, it won’t work if you want to install them in the whole vehicle.

　　Finally, let me explain that there are many factors that affect the functional safety of automobiles. Electromagnetic compatibility is only one aspect of solving the functional safety of automobiles. If it is not solved well, it will be a shortcoming of automobile safety. Through practice, if the whole vehicle setting takes the compatibility issue into consideration, it is very effective to improve the functional safety, especially in the stage of forward development, which can improve the safety level of the whole vehicle. Why do we emphasize this point? In the automotive industry, especially in which aspects do vehicle companies pay special attention? When it comes to safety, emissions, energy saving, and environmental protection, electromagnetic compatibility is often overlooked. Electromagnetic compatibility is related to safety, environmental protection, and energy saving. Safety compatibility cannot achieve an ideal effect. The problem of electromagnetic compatibility is also an important indicator of automobiles.