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Research On Electromagnetic Interference Characteristics Of Power Driver Circuits Caused By Switching Noise

Posted on:2016-02-16Degree:DoctorType:Dissertation
Country:ChinaCandidate:X Y HeFull Text:PDF
GTID:1108330503977532Subject:Microelectronics and Solid State Electronics
Abstract/Summary:PDF Full Text Request
As the core circuit in the power electronic system, the driver circuit contains semiconductor devices and that the fast switching leads to switching noises is particularly serious. The electromagnetic interference (EMI) problem caused by the noises may make the system not meet the standard of electromagnetic compatibility requirements specification, or even cause it not work normally, and affect the other surrounding circuits and systems. With the development trend of power electronic systems for the fast switching, high density, high voltage and large current, these problems will become more and more serious. However, the variously complex parasitic parameters introduced by switching devices lead to building the accurate models difficultly, the traditional methods could not made it clear that how some parameter has the influence on EMI. Therefore, it is very significative to do the research on the electromagnetic interference characteristics of power driver circuits caused by switching noise.This thesis has taken the most typical single switch device circuit and push-pull structure circuit on as the research objects, with the lighting emitting diode (LED) and the plasma display panel (PDP) driver circuit were the research cases. The researches focused on the technology of the nonlinear modeling of switching noises, the time domain and frequency domain characteristics, and the equivalent transmission path in conduction interference, the simulation characteristics in radiation interference,.etc. Based on the research results, the suppression methods for solving EMI problems in power driver circuits were provided.The innovative points in the thesis are as follows:1、The nonlinear models to describe the switching noises have been built by using the state variable method. Adopting this mathematical method, it overcame the problem of ignoring the nonlinear characteristics of switching devices in previous. The proposed models have given the clear description about the relationship between the parameters and switching noises. The simulation and test results agreed well under the different conditions, which had verified the accuracy of the predictive models. Based on the models, adopting the waveform decomposition and the spectrum analysis methods, which has considered the measurement bandwidth effect, the EMI high frequency characteristics have been extracted.2、The EMI conductive analytic models caused by switching noises have been built. It used the equivalent circuit method, and combined the propagation paths in common-mode and differential-mode EMI with different switch device states. The effects from Cgnd、Cin、Cds in the models have been analyzed by 3-D numerical simulation. Comparing with the time domain modeling, the models could judge the influence of parasitic parameters on EMI, which was beneficial to EMI suppression. 3、The 3-D space full wave simulation has been realized. Due to the large difference between working frequency and simulating in driving circuits, a linear simulation method replacing the noise source with Gauss signal has been adopted to shorten the simulation time significantly. The effects on far-field radiation intensity from the PCB surface current distribution、A、I (I/O cable)in the models have been analyzed. 4、According to the above analysis, The EMI suppression methods have been investigated from two aspects, to decrease the switching noise or to change the transmission path. Respectively, they were verified by optimizing the device parameter Cvee, R and PCB routing in the two application cases. The experimental results indicated that the optimized PDP driver circuit can suppress the switching noise less than 10% power supply voltage, and the noise peak value decreased from 191V to 154V, with its near-field EMI amplitude reduced by 8dBμV. The PDP system reliability has been improved and met relevant EMI demands. The optimized LED driver circuit can make its conductive EMI amplitude reduced by 21dBμV averagely. And the LED system has met the limit value requirements of the EN55022 standard.From three levels of theoretical analysis, computer simulation and experimental verification, this thesis has carried out the research on the nonlinear switching noise models, the analytical method for the source characteristics, the conduction interference models, and the simulation for radiation interference,.etc. And the corresponding optimization designs have been proposed, finally verified in the application cases. As a consequence, the thesis lays the foundation for a systematical study about suppressing EMI in power driver circuits, and will provide the theoretical and practical guidance for high reliability design in power driver systems.
Keywords/Search Tags:Switching Noise, Modeling and Simulation, Electromagnetic Interference, Suppression Method, Power Driver Circuit
PDF Full Text Request
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