Research Of Testing Immunity Of Main Controller In Electric Automobile To Electromagnetic Radiation

Compared with the traditional vehicles, electric vehicles'power source is motor instead of internal combustion engine, energy source is storage battery fitted in the car instead of oil. The large direct current provided by battery drive the motor run through the DC-DC or DC-AC converter. Because the current converted obtain rich harmonic, strong electromagnetic radiation will be occurred when it flows through the large inductance load or capacitive load. It has broader spectrum, from dozens of kilohertz to tens or hundreds megahertz, even to RF band, have serious interference with the broadcasting on Am band and management system clock frequency in electronic vehicle.Even so, the research agencies and car manufacturers pay no enough attentions to the electromagnetic compatibility (EMC) of electric vehicles (EV) but only care about the power capability. There are fewer people are studying the EMC of EV. In the general, when designers choice devices or components to design, function requirements are especially emphasized, and take into a few account on the requirements of EMC. They do not really realize that the difference between the traditional vehicle with the EV, and more serious bad electromagnetic environment devices and components are working in. If they do not think much of EMC in products, they will cost a lot when they improve them.Main controller of EV has functions as follow: (a) Automotive Drive Control (b) Break Energy Feedback Optimize Control (C) Automotive Energy Optimize Management (d) Net Management (e) Malfunction Diagnosis (f) Automotive Condition Observation, etc. We can say main controller is important component in EV and it affects directly reliability and safe performance of EV.Because interference of motor and inverter to main controller are serious, the main controller is in bad work condition. There isn't any big power component in main controller, and change of current in it is very small. The main controller's immunity to electromagnetic radiation should be considered. It is convenient to designing and improving of the main controller when it is tested according to the national standard in Research and Development and small quantities production. This paper does analysis and research job as follow: Starting analyze with three elements of EMC: Sensitive Source, Electromagnetic Disturbance Source and Operating Path of Electromagnetic Disturbance. From analysis, we know that the main electromagnetic disturbance sources of main controller are motor and inverter. The main controller is interfered by them. This paper gives some restrain measures to the main electromagnetic disturbance sources-motor and inverter. The analysis of operating path of electromagnetic disturbance to main controller and the introducing the soft design and hard design of main controller are the base work of this paper.Dr.C.R.Paul who works in Kentucky University has said in his article:"To last success confirmation, no other field depends strongly on measurement like EMC". The success design of main controller also depends on the test result of immunity to electromagnetic radiation.There is only one national standard relating to the test of immunity at the present time. It is GB/T 17619-1998, Limits and Methods of Testing for Immunity of Electrical/Electronic Subassemblies in Vehicles to Electromagnetic Radiation. This paper introduces the principle of the test, the requirements of the standard, and preparative for the test, such as the test environment, the test device, and setup of the test, etc. This paper proceedings deeply research to testing method of the test of immunity of main controller.The purpose of studying the testing method is researching the test. The purpose of proceeding research to test of immunity of main controller is finding the basic source of EMC problems, and then improving the EMC design of main controller. Testing experience is necessary in order to find the basic source of EMC problems. It is also necessary to understand the malfunction diagnosis measures of EMC. As a checker, the author put a scheme for testing and analysis. Through the testing examples, and adopting the kinds of malfunction diagnosis measures of EMC, such as experience analytic approach,integrated analytic approach, and tentative method, etc. Some EMC phenomena of unqualified samples are described and analyzed, and conclusions can be drawn. The author provides some suggestions to improving the design of unqualified samples. The examples of main controller may suffer from more than once improving on design, proceeding test, and malfunction diagnosis analysis and so on. But the samples can meet ultimately the requirements of GB/T 17619-1998 after that. We can draw a conclusion that EMC is a subject that is built on test and experience, and in order to get a success result, EMC design need to do many tests and accumulate much experience.In the final article, the author provides the keys of EMC design on soft and hard. They are research results of testing for main controller of EV. They are summing-up to EMC design of main controller. They can become author's work experience.Since the technology of EV just starts, there is less EMC research in my country. There is only one standard on the immunity of components in vehicles, the author has to proceeding EMC research of testing main controller only according to this standard. In order to improving the immunity of main controller and advancing EMC design of EV, new correlative national standards will be regarded to meeting the requirements of production and EMC design of products of EV.