电场测量在电力系统中具有十分广泛的应用，而针对高压直流输电线路下方的存在离子流的合成电场，目前的电场测量手段存在很大不足与局限性。本文针对对MEMS传感器在直流合成电场下的空间测量进行了研究。对直流合成电场空间测量的介入影响，理论分析，测量方案设计，MEMS机械结构选择，机械结构特性分析，尺寸优化以及工艺流程等多个方面展开了研究。通过Comsol中带电粒子追踪模块进行建模仿真，从分析带电粒子运动的角度分析了传感器的介入影响。发现充电过程结束进入稳态后，传感器附近会有一个长椭球形的空间区域电荷密度为零。并通过时域有限元法论证了这一“空区”的存在。明确了直流合成电场的介入影响与内外场关系，“空区”的存在造成的电场改变量很小，壳内电场可近似看做金属顶板附属电荷附加电场与待测量量合成电场的叠加。给出了适用于直流合成电场全场域测量的独立式复合型传感器测量方案设计，并论证了其可行性，与在直流合成电场与无离子流的标称电场下的普遍适用性。为了实现电位独立的空间电场测量，给出独立式MEMS电场传感器芯片方案，并论证可行性；详细分析对比了静电梳齿驱动与热驱动的各方面特性，最终选定了MEMS传感器的机械结构为：平面感应式与鱼骨性热驱动结构。基于Comsol制作了一个热驱动特性分析APP，对鱼骨形热驱动各结构参数对输出性能的影响进行了分析，并依据与此对热驱动机构尺寸进行了优化。对遮蔽极板机构进行了模态分析，并给出满足水平横向振动模态下的振动频率在4kHz的结构尺寸。最后设计了MEMS主结构的工艺流程。选定SOI工艺来制作MEMS机械部分主结构，绘制金属层构建、正面结构的构建和背部悬空释放三个阶段各自用到的掩膜版，分别对中每一步工艺步骤进行介绍与分析。
Measuring electric field has a very wide range of applications in the power system, but for the ion field under the HVDC transmission lines, the current measurements are insufficient. In this paper, measurements of MEMS sensor in the ion field were studied. Effect of interventional measurement, theoretical analysis, measuring program, MEMS mechanical structure selection, the mechanical structure characterization, optimization and size and other relevant aspects are researched.Firstly, by using the charged particle tracing module of Comsol Multiphysics, we figure out the effect of sensor’s intervention through analyzing the movement of charged particles. And found that when the charging process is completed, after steady state, there is a prolate spherical region near the sensor charge density is zero, which is called the “empty zone”. And by the time domain finite element method, the author demonstrates “empty zone” exists. And the relationship between inside field and outside field is figured out. The electric field directly measured by the can be approximately regarded as the sum of the space field which we aim to measure and the self-generated electric field of the charge accumulated on the metal shell of sensor’s shell.Secondly, presents the independent dual sensor design and demonstrate its feasibility, and universal applicability no matter in the ion field and nominal electric field.Thirdly, in order to realize the electric field sensor in independent space potential，a kind of cordless MEMS-EFS chip solution is designed, and the feasibility is demonstrated. Then detailed analysis and comparison of the various characteristics of electrostatic comb drive and thermally driven is made. The final selection of the mechanical structure of the MEMS sensor : parallel vibrating shutter electrodes and thermal actuators.Lastly, based on Comsol Multiphysics, an App is made to analysis the influence of the structural parameters on the output performance, and based on the previous work, structural parameters are optimized. Then fabrication processes of the main MEMS structure are designed. SOI MEMS technology is selected to produce the main MEMS structure, every step of the process steps is described and analyzed.
