Research On Wiper System Of Automotive EMC Based On The Synergetic Theory

After so many years of development, automotive industry has matured. With the development of economy, people have higher demand on the performance of various aspects of the automobile. The development of today's cars most relys on the development of automotive electronics. Because of the introduction of automotive electronics, all aspects of vehicle performance has been greatly improved, however, at the same time, it also brought to the automotive electromagnetic compatibility (EMC) problems. In recent years, with the development of automotive electronics,the electromagnetic environment of automobile is getting more and more worse. The problem of automotive EMC has been became worse day by day. People begin to pay more attention on the research of EMC. The traditional research methods of EMC generally based on experience, but as the complexity of automotive electric system and the deterioration of external electromagnetic environment, we can no longer use simple the mathematical models to describe and analyze the electromagnetic compatibility of automobile electronic systems. At present, the research methods of combining the modeling and simulation with the actual test is becoming the hotspot of automotive EMC research. However, the modeling theory and application technology of automotive EMC still stop at the technical level, there is no research on systematic general theory of modeling.Synergetic ideology , founded by the German physicist Haken, is a kind of systemic science. It's main research contents is how to create time, space or functional structure by self-organization among the various subsystems, when the system is far from steady state. The main target of Synergetic Theory is the system which is in a state of non-equilibrium phase transition, research the universal law of complex structure in evolution of nonlinear systems Synergetic ideology has great advantages in solving the problem of systemic variation, especially for complex systems. The automobile is a very complex system, which also has very complex electromagnetic environment. The thought and related research methods of Synergetic Theory can effectively solve the complex issue of automotive EMC. This paper use Synergetic ideas on automotive EMC to simplified the modeling of EMC, study the automotive EMC on system's level, to get a general method on automotive EMC. Such a complex system for the car, we must have careful analysis for finding the slow relaxation variable and fast relaxation variable, then effective simplified the model of electromagnetic compatibility through the slaving principle of Synergetic Theory.This article is a part of the subject of Automotive Electromagnetic Compatibility Field Analysis and Digital Simulation. In this paper, wiper system, which has a lower passing rate of EMC, was became an object of research. It has focused on the problems, such as the EMS of motor in the Wiper system, the EMI of switch and the electromagnetic radiation of motor and so on. According to the analysis of electromagnetic motors and the methods of Synergetic principles, we have found the slow relaxation variable of EMS, listed the order parameter equation of EMS in motors by using slaving principle of Synergetic Theory. And we seize the key factor of EMS in motor, it help to simplify their EMS model. Switch has always been one of the key consideration of electromagnetic interference, it affects the electromagnetic compatibility of the system. The EMI of switch is mainly in the moment of Switch Turns, compared with the EMI of switch in the moment of Switch Turns, their electromagnetic interference in normal working hours is almost be ignored. The variety of voltage in Switch Turns equals to a step signal. This paper has analyzed the distribution of the spectrum about the electromagnetic interference in Switch Turns, the experimental results have shown the validity of theoretical analysis. And then combining the experiment, the relevant measures have been taken to inhibit the EMI, we have designed active band-stop filter circuit. The electromagnetic interference of switch has been greatly reduced after taking control measures. For wipers motor, firstly, this paper carefully has discussed the principle of its work and some of the magnetic changes in work, then researched the motor commutation process which is a key part of impacting the electromagnetic interference. The commutation of permanent magnet DC motor is impossible linear and no spark. Wiper motor in the run-time will have a strong electromagnetic interference, motor produces strong pulse oscillation in the process of commutation. The electromagnetic interference in the process of commutation affects the electromagnetic compatibility of wiper motor, deteriorates the electromagnetic environment around it, threatens the normal work of other electric appliances in the car. Based on analyzing of the circuit model of the motor commutation process, this paper has derived the commutation current function of time, also got the voltage which affects the electromagnetic radiation about motor. It has found out the key factor which affects the electromagnetic interference by analyzing. Based on theoretical analysis and modeling and simulation, in accordance with electromagnetic compatibility testing standard, the motor's electromagnetic radiation experiments have been done, the experimental images coincident with the previous analysis. By the radiation characteristics of motor and the method of Synergetic Theory, we have taken appropriate measures to inhibit the EMI.Based on Synergetic Theory, we have analyzed the order parameter equation of the motor of wiper system resisting the Electromagnetic Interference(EMI),researched the EMI of power switch of wiper system and motor. According to analysing and modeling, found out the reasons for EMI, and took corresponding measures for EMI suppression. We have verified the rationality and effectiveness of analysing the automotive EMC based on Synergetic Theory through experiments. By improving the related structures of motor, Shielding and filtering, the electromagnetic radiation has been decreased by 16dB, basically achieved the desired aim.This paper only simply thought of the use of Synergetic Theory on the EMC of wiper system in automobile, there are many related research needs to be done ,but it used Synergetic Theory successful in the new field of automotive EMC, injected fresh blood into the automotive EMC research, brought a new idea, opened a new field of application of Synergetic Theory. Through the study of this paper, we found that it is effective and desirable for Synergetic Theory to solve the complex problems such as automotive EMC.In conclusion, this paper applied Synergetic Theory to the EMC about car wiper systems, the corresponding models have been established, the concrete solutions have been put forward , and the expected results have been got. The experiment results shown that the synergetic approach to the electromagnetic compatibility of automobile is feasible. It has very important significance to solve the issue of automotive EMC.