直/交流电源侧传导EMI噪声机理诊断与抑制技术研究

【作者】 刘勇；

【导师】 赵阳；

【作者基本信息】 南京师范大学 ， 电工理论与新技术， 2014， 硕士

【摘要】 随着高频集成电子芯片、功率晶体管、开关电源的广泛应用,随之导致的传导电磁干扰(Electromagnetic Interference, EMI)问题越来越受到重视,所以如何快速有效解决不同供电方式下的传导EMI问题成为传导电磁干扰技术研究的关键之一。因此本课题开展了直/交流电源侧的传导EMI噪声机理诊断与抑制技术研究。首先,本文开展了直流电源侧的传导EMI噪声机理研究,分析了直流人工电源网络的工作原理,提出了其高频等效电路模型并进行了高频特性参数的仿真分析；结合直流供电的特点,提出了一种用于直流侧噪声源内阻抗提取的方法,并用实验验证了该方法的可行性；此外,建立了直流侧的共模和差模干扰模型,在高频DC/DC变换器的传导EMI噪声机理模型的研究基础之上,基于Pspice软件建立了高频DC/DC变换器的传导EMI噪声仿真模型,并进行了干扰噪声的仿真分析。其次,本文开展了交流电源侧的传导EMI噪声机理研究,分析了交流人工电源网络的工作原理,并提出了基于电流探头法的传导EMI噪声诊断方法；在现有基于双电流探头法的噪声源内阻抗提取原理之上,提出了双阻抗法和非线性最小二乘法的噪声源内阻抗提取方法,并用实验验证了该方法的可行性与准确性；此外,对交流电源侧传导EMI噪声机理进行了建模分析,提出了交流侧共模和差模干扰噪声电流的传输路径模型,并对基于控制参数影响的传导EMI噪声特性进行了理论与仿真分析。最后,本文开展了直/交流电源侧的传导EMI噪声抑制方法研究,对因串扰、接地不充分和线路阻抗不匹配等导致的传导EMI问题进行了干扰机理描述,然后在此基础之上,对不同原因导致的传导EMI问题提出了相应的抑制方法。最终本文以新能源逆变系统、食堂刷卡机和车用影音设备的传导EMI问题为实例进行了分析,并且分别提出了抑制措施,实验结果均较好验证了抑制措施的有效性,采用抑制措施之后的设备均能通过标准检测。更多还原

【Abstract】 With the widespread application of high-frequency IC chips, power transistor and switching mode power supply, more and more attention is paid to the conducted EMI problems. So it is a key point for the conducted electromagnetic interference technology research to study how to solve the conducted EMI problems under different power supply methods. As a result, the conducted EMI noise diagnosis and suppression technology on the DC/AC power supply sides is researched in this paper.Firstly, the research on the conducted EMI noise mechanism of the DC power supply side is carried out in this paper. The working principle of DC artificial mains network is analyzed and its high-frequency equivalent circuit model is proposed, and its high-frequency characteristic parameters are analyzed by simulation. Considering the DC power supply feature, a method is proposed to extract the noise source impedance on the DC side, and the experiment results verify the feasibility of the method. Besides, the common mode and differential mode interference models are established, and on the basis of the research on the conducted EMI mechanism model of the high-frequency DC/DC converter, the simulation model of the high-frequency DC/DC converter conducted EMI noise is established and the interference noise is analyzed by simulation.Secondly, the research on the conducted EMI noise mechanism of the AC power supply side is carried out in this paper. The working principle of AC artificial mains network is analyzed and the conducted EMI noise diagnosis method based on the current probe is proposed. On the basis of the noise source impedance extraction theory based on double current probes, the double impedance method and nonlinear least squares method are proposed to extract the noise source impedance, and the experiment results verify the feasibility and accuracy of the methods. Besides, the modeling of the conducted EMI noise mechanism of the AC power supply side is established and analyzed, and the transmission path model of the common mode and differential mode interference noise current is proposed. What’s more, the conducted EMI noise characteristics affected by control parameters are analyzed by the theory and simulation.Finally, the conducted EMI noise suppression methods on the DC/AC power supply sides are researched in this paper. For the conducted EMI problems caused by crosstalk, inadequate grounding and line impedance mismatch, the corresponding interference mechanisms are described. Then on the basis of the mechanism description, the corresponding suppression methods are proposed to solve the conducted EMI problems caused by different reasons. At last, the conducted EMI problems of new energy inverter system, canteen card machine and car audio-visual equipment are taken as experimental subjects, and the suppression methods are proposed respectively for the conducted EMI problems after analysis. The final experiment results well verify the effectiveness of the suppression methods, and the equipments can all pass the standard test after applying the suppression methods.更多还原