Equivalent circuit modeling of discharge current injected in contact with an ESD‐gun

The transient electromagnetic (EM) fields caused by an electrostatic discharge (ESD) have broadband frequency spectra, which cause serious failure to high‐tech information equipment. From this perspective, ESD testing for the EM immunity of the equipment is specified by IEC 61000‐4‐2, in which the detailed waveform of the discharge current injected onto the IEC recommended Pellegrini target in contact with an ESD‐gun is prescribed for calibration. However, the factors for determining the current waveform remain unclear, and thus the IEC prescribed current waveform is unlikely to be injected into actual equipment. In this study, based on the structure of an ESD‐gun, an equivalent circuit modeling is proposed for analyzing the discharge current injected onto a 50‐Ω SMA connector instead of the IEC target that has frequency‐dependent transmission characteristics. Its validity is confirmed by comparing the calculated current waveform with the measured result. The proposed circuit modeling is also validated from measurement of the discharge current injected onto a transmission line by the ESD‐gun. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(1): 8–14, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10367     

Calculation of magnetic near field generated by the contact discharge of an ESD gun

An ESD (electrostatic discharge) testing is specified in the IEC 61000‐4‐2, in which the detailed waveform of the discharge current injected by an ESD gun is prescribed. However, due to lack of understanding of the discharge process, it is difficult to confirm whether or not the IEC current waveform can be injected onto actual equipment. We thus previously proposed an equivalent circuit model for the ESD gun based on its geometrical structure, and showed decisive factors for the discharge current. In this study, in order to confirm the feasibility of the above equivalent circuit model, we measured with a 6‐GHz wide‐band digital oscilloscope the discharge current through an SMA connector and the resultant magnetic near field for the contact discharge of an ESD gun. As a result, we found that both measured waveforms approximately agree with those calculated from our equivalent circuit model. We then measured with respect to charge voltages the magnetic near fields for the contact discharge of the ESD gun to the ground, which revealed that the measured waveform around the first peak is in fair agreement with the calculated one. Furthermore, we found that the magnetic field peak increases with increasing charge voltage, whose dependence can be predicted from our equivalent model. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(1): 17–24, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20194     

Characteristic measurement of discharge current injected by the air discharge of an ESD gun onto a ground

An immunity testing method for electrostatic discharge (ESD) is being specified in IEC 61000‐4‐2, in which the contact discharge of an ESD gun is being normally specified. Air discharge testing is known to be a severe immunity test compared to contact discharge testing, while the discharge current injected is not well reproduced. Grasping the behavior of the current injected by the air discharge would be helpful in establishing the worst‐case ESD immunity testing. We previously measured the discharge currents for air discharge testing onto the IEC‐recommended current transducer with a commercially available ESD gun, and showed that there exists a specific relationship of Ip·tr^ξ/V_c=constant (ξ=0.75), between rise time tr and current peak Ip. The current transducer, however, has a frequency‐dependent transfer impedance which should affect the measured current waveform. In this study, we investigated whether the above‐mentioned specific relationship can be obtained for air discharge of an ESD gun onto a ground that assumes a metal enclosure of electronic equipment under test. A method was presented for estimating the discharge current from simultaneously measured magnetic fields with two magnetic field probes regardless of the distance between the gun discharge‐point and the probe position. This method was validated for contact discharge of an ESD gun to an SMA connector. With this method, we estimated the discharge currents injected onto a ground for air discharge testing of an ESD gun with intentionally fast and slow approaches. As a result, we could confirm a specific relationship between rise time tr and current peak Ip of Ip·tr^ξ/V_c=constant with ξ=0.57 independent of charge voltages and gun approaches. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 158(4): 51– 59, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20454     

对空气式静电放电的研究

为改善空气放电模拟方法,用静电放电模拟测试装置研究了IEC标准规定的空气式静电放电的放电特性。通过手动方式使充电后的放电电极快速靠近电流靶获得空气静电放电事件,放电电压具有2~20 kV较宽范围的电压电平和正负电压极性。利用Agilent数字存储示波器测量了空气静电放电放电电流的上升时间、峰值以及耦合到自制的金属半圆环上的峰-峰值电压,并记录了放电电流和耦合电压的波形。通过分析和比较测量结果研究了测量参数随放电电平的变化趋势。空气放电电流的特性与静电放电抗扰度试验标准IEC 61000-4-2对接触式放电的规定类似,耦合电压与放电电压之间没有直接的相关性。实验表明在一定电压范围、电极速度可控时可能获得空气放电的重复性。     

IEC61000-4-2规定的实验平台与方法的局限性

研究了静电放电抗扰度试验,发现满足IEC6100042标准规定的不同的ESD模拟器对同一试验对象所得实验结果不同;放电电流导数和模拟器内部开关继电器的电磁辐射对实验结果有很大影响。分析认为,造成上述问题的原因之一是IEC标准对电流校验波形的规定不够严格,未具体规定空气放电方式,使实验结果与实际不符。最后建议标准应规定电流导数波形参数,限制电流波形的振荡;必要时应对模拟器开关采取屏蔽措施,限制模拟器开关的辐射;应进一步研究空气放电的特点,建立符合实际应用需要的实验平台。     

空气式静电放电抗扰度试验方法

静电放电(electrostatic discharge,ESD)抗扰度试验作为电磁兼容(EMC)试验的一项重要内容,其执行标准IEC 61000-4-2还存在诸多问题,尤其是空气式ESD的重复性问题。为此,基于动能-势能转换原理,采用导轨带动电极运动结构和步进电机装置,用近似单摆结构的试验方法,设计和研制了2种新的ESD抗扰度试验平台,实现了空气式ESD抗扰度试验中对放电电极接近速度的准确控制。利用这2种ESD抗扰度试验平台对空气式ESD的重复性进行了研究。试验结果表明,ESD参数如放电电流峰值、接近速度和放电电压具有很好的规律性,并且在一定的放电电压和接近速度下,空气式ESD也可以具有较好的重复性。在相同放电电压和接近速度下,利用第2种ESD抗扰度试验平台得到的放电电流峰值和上升时间的变异系数均小于利用第1种ESD抗扰度试验平台得到的放电电流峰值和上升时间的变异系数,因此第2种单摆式ESD抗扰度试验平台的重复性要好于第1种ESD抗扰度试验平台的重复性。     

聚合物ESD抑制器抑制特性的测试方法

为了消除静电放电时产生的辐射场对静电放电抑制器测试结果的影响,基于法拉第笼的屏蔽效应、依据国际电工委员会IEC61000-4-2标准和国军标GJB911-1990,利用静电放电模拟器和静电放电电流波形测试装置等设备,测试了某型号聚合物静电放电抑制器的抑制特性。测试结果表明,采用IEC61000-4-2标准规定的电流靶结合法拉第笼的方法,测试静电放电时通过抑制器的电流,能够保证电流波形不失真;而加在抑制器两端的电压,须使用有效带宽足够宽的电压探头配合示波器来测量,同时应尽可能消除静电放电时产生的辐射场对电压探头的影响。     

智能电器监控单元静电放电敏感性的实验研究

为研究智能电器监控单元的静电放电敏感性,利用静电放电发生器对设备机壳放电进行了实验研究。根据静电放电干扰的耦合途径以及智能电器监控单元的实际工作情况,选取电源模块直流侧电压作为研究智能电器监控单元的静电放电敏感性的对象,通过频谱分析得出直流侧对地电压和静电放电电压间的关系。装置采取屏蔽、接地和滤波等抗干扰措施时其静电放电敏感性降低,分析直流侧电压发生的相应变化得出结论:静电放电时,智能电器监控单元直流侧对地电压与装置的静电放电敏感性有一定的相关性。     

ESD电流的解析表达式与数值解

分析IEC6100042静电放电(ESD)电流波形典型拟合解析表达式表明,这种由有限点拟合曲线的纯数学方式存在拟合的多样性,无可依据的物理基础。因而根据ESD物理特性提出了一种通过数值计算等效电路模型获得ESD电流数值解的方法,由该方法算出的电流峰值、上升时间、i30ns、i60ns等关键参数与IEC610042电流波形参数的相对误差的最大值均<1.6‰,为ESD辐射电磁场研究提供了有效的手段。     

IEC61000-4-2标准试验平台的局限性分析及其完善的探讨

为解决国际标准IEC 61000-4-2规定的静电放电(ESD)抗扰度试验平台存在的局限性,通过分析ESD模拟器开关动作、ESD电流及其导数、ESD辐射场、试验结果的判定准则和试验方法的不完善规范对ESD抗扰度试验的影响,探讨了IEC标准试验平台问题存在的原因.研究发现,ESD模拟器开关动作对试验结果会产生很大影响,其...     

A Verification of Estimation Accuracy of Lightning Current Waveform and Charge Transfer from Measured E‐Field Waveform

To establish effective countermeasures on power facilities against lightning damage, it is necessary to clarify the lightning characteristics such as current parameters at the area of interest. In order to collect lightning current parameters effectively, the authors have observed electric and magnetic field waveforms simultaneously at south Kyushu, where the lightning flash density in summer is high. Based on observed electric field waveforms, the lightning current parameters have been estimated by adopting the Diendorfer–Uman model (DU model) as the return‐stroke model. In this paper, the accuracy of the estimated return‐stroke current waveform is verified by comparison with directly measured return‐stroke current waveform, along with the accuracy of the estimated charge transfer from the electric field waveform measured with a slow antenna.     

基于PLC的静电放电试验系统的设计

设计了基于可编程控制器(PLC)的静电放电实验系统,对静电保护器件压敏电阻进行静电放电自动测试。首先根据IEC61000-4-2标准,设计静电放电发生源回路,选择可控放电频率的转盘式放电开关和具有纳秒级响应时间和集肤效应小的鼠笼式分流器。其次设计由工控机、示波器、PLC、触摸屏等组成的控制系统,开发相应的控制软件及数据处理系统,实现静电放电自动测试。最后选用不同等级的压敏电阻作为测试对象,对测试装置进行实验验证,结果表明,研究开发的静电放电自动测试装置可以满足压敏电阻静电放电测试的要求,对压敏电阻静电防护的研究具有重要意义。     

空气式静电放电的实验分析

针对国际电工委员会标准IEC 61000-4-2静电放电抗扰度试验方法存在的问题,对空气式静电放电进行实验研究.利用新型静电放电(ESD)模拟测试系统,在较宽范围的电压电平下,用数字存储示波器对放电电流的上升时间、峰值、自制金属半圆环天线上的耦合电压峰一峰值进行测量.测量结果的分析表明:不同空气湿度下的ESD特性存在着...     

ESD辐射场的计算及对传输线的耦合研究

为分析静电放电的辐射场及其对传输线与负载终端的影响,采用了一种基于脉冲函数的静电放电电流波形解析表达式计算了静电放电电磁脉冲辐射场并给出了近场和远场波形。结果表明放电电场包括由初始电荷引起的静电场和由放电电流引起的辐射场,在放电电极附近,静电场远大于辐射场,但静电场随空间距离衰减得很快,在远区场主要由放电电流引起的辐射场。利用传输线理论建立静电放电场对电长导线的耦合计算模型得出了静电放电辐射场在线上的感应电压和感应电流计算方程。     

Negative First Return‐Stroke Current Peaks and Impulse Charge Transfer

For the effective and efficient insulation design of a power line, the return‐stroke current waveform parameters are indispensable. Charge transfer is one of the important parameters when damage to equipment on a power line due to the energy of lightning is discussed. The amount of charge transfer associated with a lightning flash or individual strokes can be estimated by using the electric field change obtained with a slow antenna. The authors observed the electric field waveforms in south Kyushu for the purpose of efficient acquisition of return‐stroke current parameters. In this paper, the authors discuss the relation between the negative first return‐stroke current peaks and the impulse charge transfer based on the observed electric field waveforms.     

直流局部放电干扰源研究

局部放电作为影响绝缘老化的主要原因之一,是评估电气设备绝缘性能,研究绝缘老化趋势的重要手段。为掌握直流下局部放电波形的特性,笔者结合直流换流阀试验,对悬浮电位、高压尖端放电、地尖端放电3种典型缺陷的直流局部放电典型干扰源进行模拟研究。在直流电压逐步升高的情况下,从放电脉冲的极性、放电脉冲的位置、放电脉冲的幅值、放电脉冲的根数4个方面对特征进行总结、归纳,为直流下缺陷类型的识别奠定了基础。     

应用粒子群优化算法的静电放电模型参数辨识

为了获得精确的静电放电模型,提出了一种应用粒子群优化算法的静电放电模型参数辨识新方法。以Heidler雷电流方程的静电放电模型参数为辨识对象,分别以仿真及实验数据验证了该方法的可行性,并从电流波形的整体和局部两方面对拟合效果进行了评估。结果表明,与遗传算法相比,粒子群优化方法的执行速度更快,所得的辨识参数精度更高,粒子群优化方法对电流波形的整体和局部关键点的拟合度均高于遗传算法。因此,粒子群算法较遗传算法更适用于解决静电放电模型参数辨识问题。此外,从实例可以看出,粒子群算法不需要过多的初始参数值先验知识,而只须提供一个较宽的初始参数搜索范围即可获得良好的辨识结果。     

电晕电流及其辐射信号特性的研究

为得到电晕放电辐射场的时域和频域特征,采用针板结构首先对电晕电流及其辐射场进行了理论分析,然后在此基础上对电晕电流及其辐射信号进行了实验研究。实验表明,电晕电流脉冲波形具有明显的极性效应:①负极性下先发生电晕放电,但正极性放电发生时,脉冲幅值比负极性时大;②负电晕电流脉冲波形的上升时间小于正电晕电流。实验结构不同,电晕放电辐射场的特征不同:利用第①种实验结构得到的放电波形的上升时间为十几个ns,频率分布范围集中在20～100MHz;利用第②种实验结构得到的放电波形的上升时间为几个ns,频率在200～600MHz。该结论对于下一步研究空中带高压物体的电晕放电辐射信号特征具有参考价值。     

Study concerning production of lightning overvoltages on low‐voltage power distribution lines

In order to study lightning problems of low‐voltage power distribution lines, lightning overvoltage waveforms were observed inside the homes of customers. The cause of lightning overvoltages was examined from observation of striking points by still cameras. Lightning overvoltages of 62 waveforms were recorded by observation over a period of about 3 1/2 years. Observed waveforms can be classified into three types of single polarity (positive or negative), both polarities (which change from positive to negative or negative to positive), and pulsive waveform. The causes of these lightning overvoltages which were estimated from striking points are shown as follows: (1) Induced lightning overvoltages on low‐voltage distribution lines. (2)   Electric potential rise due to discharge of surge arresters or current of overhead ground wire. (3)   Shift of lightning overvoltages from high‐voltage side of transformer to low‐voltage side, which is due to electromagnetic induction. © 2000 Scripta Technica, Electr Eng Jpn, 130(4): 66–75, 2000     

一种新型ESD电压发生器的设计与调试

针对静电放电(Electro-static Discharge.简称ESD)对芯片造成损伤的现象,研究了静电放电发生的过程及产生的原因.首先阐述了几种常见的模拟静电放电过程的模型,然后利用彩色电视机的一体式行回扫变压器作为直流高压源、串联SCR作为高压开关,设计并制作出符合IEEE Std C62,38-1994标准的ESD人体模型实验发生仪器,并对ESD人体放电模型中的body/finger模型进行了实验模拟.最后给出放电电压为4kV时测量的ESD电流脉冲波形,并与理想放电波形进行对比,其结果验证了该方案的可行性和易操作性.