The significance of electromagnetic compatibility testing of motors and controllers of new energy vehicles

With the development of economy and society, the situation of traditional energy is increasingly tense. In the context of increasing energy demand, actively developing new energy has become the consensus of all sectors of society. New energy vehicles are a typical example of the development of new energy for automotive electronics. Compared with traditional vehicles, one of the biggest characteristics of new energy vehicles is the difference in power systems. The power system is the core of a car and the key to energy saving.

The core equipment of the power system of new energy vehicles is the motor and controller. The performance of motors and controllers directly affects the overall performance of new energy vehicles. Traditional energy sources are increasingly tense, while new energy sources are in the ascendant. Strengthening EMC testing of new energy vehicle motors and controllers can help ensure the quality of new energy vehicles and improve their performance.

1. Reasons for the compatibility test of the powertrain of new energy vehicles

The driving motor system is mainly used in the power system of new energy vehicles in China, which has great advantages compared to traditional internal combustion engine systems. At present, the power system of new energy vehicles in China is still in the research stage and has not yet been popularized. During normal operation, the power system of new energy vehicles will emit strong radiation and electromagnetic interference, due to the rapid movement of high-power semiconductor switches and the pulsation of electric current in a short time. For example, although the switching time of a gate bipolar transistor is only a few tens of nanoseconds, it can generate strong electromagnetic interference during these tens of nanoseconds. Electromagnetic interference in the power system can seriously affect the performance of new energy vehicles and the power consumption system of new energy vehicles. Therefore, in order to reduce electromagnetic interference, it is necessary to strengthen electromagnetic compatibility testing.

At present, China's new energy vehicle compatibility testing technology is not very mature, and there is still a significant gap compared to other countries. The compatibility testing of the powertrain of new energy vehicles in China mostly adopts the traditional internal combustion engine drive system and weak current system standards. Currently, there is no complete and scientific new energy power system compatibility testing standard in China. This is worth our reflection.

2. Contents of power system electromagnetic compatibility test

The electromagnetic compatibility testing of the power system of new energy vehicles mainly refers to two measures: first, interference testing; The second is interference immunity test. To achieve scientific testing, it is necessary to accurately grasp the meaning of these two aspects and conduct testing in strict accordance with relevant national standards.

2.1 Harassment testing Harassment testing mainly refers to testing the protection ability of personnel within a certain distance. The current standard for harassment testing is GB14023-2006. Compared to the original standard, although this standard expands its content and meets some requirements for new energy vehicles, in the final analysis, it is a standard for internal combustion engines.

This standard cannot be tested scientifically. This standard mainly calculates the operating status of the tested object per kilometer per hour, while new energy vehicles are measured per revolution per minute. There are significant differences in the calculation standards between the two. In addition, different layouts are also the main reason for compatibility testing failures. The testing of the powertrain of new energy vehicles is significantly different. The layout of the two is significantly different. This makes compatibility testing meaningless.

2.2 Immunity test Immunity test mainly refers to the test on the ability of electronic components of motor vehicles to resist electromagnetic radiation. At present, the reference standard for immunity testing in China is GB/T17619-1998. This standard clearly specifies immunity limits and test methods. Since the electromagnetic compatibility testing environment of the drive motor system is approximately the same as that of traditional vehicle models, it is also feasible to use GB/T reference 17619-1998.

3.Feasibility Plan for Electromagnetic Compatibility Testing of New Energy Power Systems

After understanding the main content of power system compatibility testing, the author discusses the feasibility of electromagnetic compatibility testing for motors and controllers in new energy power systems. Compatibility testing of drive motor systems mainly considers two factors: first, specifying the test object; The second is to scientifically arrange the drive electromechanical system and effectively supervise the operation.

The main goal of our electromagnetic compatibility testing of new energy vehicle power system motors is to drive the entire motor. The traditional test method is to separate the main components of the power system and the inverter for independent testing. The layered testing method has poor testing effect and high testing cost. Therefore, we should adopt a holistic measurement method to test the compatibility of the drive motor system.

Scientific layout of the drive motor system. The layout of the drive electromechanical system has an important impact on the test results. Careful selection of layouts during testing is key to ensuring correct measurement results. At present, the relevant standards in China have not clearly stipulated the layout method or although there are some provisions, these provisions cannot be adapted to the testing of drive motor systems. Therefore, when arranging the drive motor system, the layout method of the simulation experiment is mainly referred to.

During system compatibility testing, it is generally necessary to load the drive motor system. Loading and driving electromechanical systems can effectively improve the emission level. The author specifically conducted this experiment, and together with professionals, the author built a trolley dedicated to testing. In this vehicle, the drive motor system is mainly loaded through a chassis dynamometer.

After loading in this way, by observing the experimental data, the author found that the emission level has greatly improved, 50 dB more than the average level. System loading is the key to improving the performance of drive electromechanical systems. During the measurement process, a conditional loading system should be used. While seeing the benefits of system loading, it is also important to realize that there are many limitations in the loading process of new energy vehicle systems in China. The most typical factors are two: first, to achieve system loading, a special semi anechoic chamber needs to be set up, at which time the testing cost will be high; The second is that the current system loading technology in China is not mature and cannot adapt to complex situations. When testing the compatibility of drive motor systems, the above two factors must be fully considered. Optimize compatibility testing under established conditions.

4 .Compatibility Test Standards

After understanding the feasibility of measuring the power system of new energy vehicles, you should also accurately grasp various test standards. Mastering these compatibility testing standards is important for scientific testing. The selection of reference standards for compatibility testing is mainly carried out from the following aspects:

One is emission from radiation. Currently, the reference standards for radiation angle are mainly GB18655-2002 and GB/T18655-2002. These two standards are mainly used to measure the receiving devices of new energy vehicles. These two standards are widely used. The drive motor system can be applied to both standards, so that each device in the vehicle can achieve better performance. For example, the author conducted a professional investigation on the drive motor system of new energy vehicles from the perspective of radiation, and found that the vehicle's load meets the GB18655-2002 standard, but the radiation protection performance needs to be improved.

The second is radiation immunity. For the measurement of radiation immunity, radiation immunity is mainly used. GB/T Test 17619-1998. The main reason why we use this standard is that the measurement standard has clearly defined the immunity limits and measurement methods. The measurement frequency range is also clearly defined. This standard is not specifically used to measure the electromagnetic compatibility of motors in new energy power systems, but because the electromagnetic radiation environment is not significantly different from the standard radiation environment, we have adopted this standard for testing.

The third is conducted immunity. The conducted immunity test is mainly based on the conducted immunity ISO7637-3-2007 and ISO7637-2-2004D waiting standards. These standards specify 24 vehicles. Test method for transient conducted immunity of V power lines. According to this standard, conducted immunity has eight pulse forms, each of which is. 2a. 3a. 3b. 2b. 45a. 5b. The first four forms can be used for compatibility testing.

With the increasingly tense situation of traditional energy in China, accelerating the development of new energy has become the consensus of all sectors of society. At present, the development and application of new energy vehicles in China has effectively alleviated the energy shortage situation. However, due to the strong electromagnetic radiation emitted by the power system of the new energy itself during normal operation, electromagnetic compatibility testing of motors and controllers is very important.