薄膜电子式电—气转换器转换模块与控制系统研究

【作者】 李伟；

【导师】 孙宝元；

【作者基本信息】 大连理工大学 ， 机械电子工程， 2004， 硕士

【摘要】 电-气转换器是自控仪表和自控系统中进行信息转换和能量转换的核心元器件，主要用于电动单元组合仪表与气动单元组合仪表之间的信号转换，可将4～20mA(DC)电信号转换成10～120kPa的压力信号，以便实现对各种管路阀门等气动装置的自动控制，可广泛应用于石油、化工、冶金、轻工等部门。在综合分析国内外电-气外转换器相关领域研究现状后，研制开发了薄膜电子式电-气转换器，具有响应速度快，转换效率高等特点。 薄膜电子式电-气转换器的转换装置采用全闭环磁路包容喷嘴／挡板结构，实现气路、磁路一体化；以中间有硬芯的平膜片作为挡板，提高了系统的动态响应特性。膜片在整个转换装置中是唯一可动的元件，对系统性能影响非常大，本文重点分析膜片的变形特性，受力特点，并以膜片为中心，将气路特性、磁路特性联系在一起，经过分析，喷嘴挡板间隙S和锥体位移L是影响转换模块性能的主要的因素，为进一步优化结构参数优化、优化工艺参数打下基础。采用的绝对误差意义下的贝叶斯估计对膜片可靠度进行了初步探讨。 薄膜电子式电-气转换器以闭环比例积分为控制方式，以精密压力传感器提取反馈信号，利用电量的平衡、比较和调节，实现闭环实时控制，提高了电／气转换器的转换精度、转换速度和转换效率。本文对控制系统进行系统分析，建立了系统传递函数，从中可以了解系统稳定性、稳态误差和瞬态响应特性，为下一步进行计算机虚拟调试打下基础。更多还原

【Abstract】 Electro-pneumatic converter is core element of information transform and energy transform in auto-control and auto-system. It is mostly used in signal transform between electromotion cell assembled instrument and pneumatic-motion assembled instrument. It is able to convert 4~20mA(DC) electro-signal into 10~200kPa pressure-signal, so it can realize the auto-control of various pipeline and valve. It aboard applies in petroleum and metallurgy. Looking through the research status in related field home and abroad, the membrane electro-pneumatic converter is developed, which leads to prompt response and high converting ratio.The membrane electro-pneumatic converter’s transform device adopts pneumatic-magnetic circuit incorporated nozzle/flapper structure which realize the incorporation of pneumatic-magnetic. Flapper, which is made of flat membrane with rigid center, enhances dynamic response characteristic of system. Membrane, which is only movable element in whole of transform device, has greatly influence of performance. This article mostly analyzes the distortion and standing force of membrane. It is base on the combined of pneumatic-magnetic circuit which optimize structure and technics parameters.Close-loop PI automatic control and the accurate solid-state pressure sense, which is able to distill feedback signal, are used in the membrane electro-pneumatic converter. It can utilize electricity to balance, compare and adjust signal. The close-loop feedback real time control achieves the high conversion precision, conversion velocity and conversion ratio. This article establishes transfer function on the base of analyzing control system. System stability, steady error and moment response characteristic are obtained from transfer function. It provides foundation of computer virtual debugging.更多还原