【作者】 王少飞；

【导师】 堵国樑；

【作者基本信息】 东南大学 ， 电路与系统， 2016， 硕士

【摘要】 复合真空计是用于测量真空度的工具之一,其性能指标将直接影响科研、生产任务的完成质量。随着科学技术的发展,进一步提高真空计测量指标与数字化程度,具有一定的研究意义和实用价值。论文目的是研究与设计一种由电离规和电阻规复合的宽量程真空计。文章主要对直接影响高真空测量指标的稳定发射电流控制、离子流检测电路展开研究。首先明确高真空测量对电离规发射电流稳定的需求指标,结合被控对象特征,进行了常用控制算法在稳发射电流应用中的可行性分析,在此基础上,重点讨论了参数模糊自整定PID算法控制发射电流稳定的原理,对其功能进行仿真分析,并在单片机平台上实现了发射电流的数字闭环稳定控制。其次在对离子流信号的产生机理、检测影响因素进行分析后,选取基于T型电阻网络的改进型I-V转换法作为离子流信号检测方案,电路跨阻增益可切换、并对信号进行多级滤波以抑制噪声,使电路能够覆盖检测从皮安到微安的6个量级电流信号。复合真空计测试从稳定发射电流、离子流信号检测功能模块电路和系统整机三个方面进行。结果表明,离子流信号测量范围1pA～6uA,测量分辨率0.2pA,噪声小于1.5mV；电离规发射电流、加速极、阴极对地电位示值误差及时间稳定度均小于±0.8%；电阻规1Pa-103Pa主要测量范围内,示值误差不超过±10%；电离规10-8Pa-10-1Pa测量范围内,等效离子流法测试示值误差不超过±1%。测试结果符合JBT10074-2004、JBT7463-2005等现行国家标准规定,能够满足一般工业生产及科学研究中的真空测量要求。更多还原

【Abstract】 Composite vacuum gauge is one of the tools used to measure the degree of vacuum, whose performance will directly affect the quality of the completion of scientific research production tasks. With the development of science and technology, it has a certain practical significance to further improve the measuring indexs and degree of digitization of the gauge.The study and design of a wide range vacuum gauge combining ionization gauge with resistance gauge is presented in this thesis.Research is mainly done on the emission current stability control and the ion current detection circuit, which have an direct effect on the measurements of high vacuum measurement in the thesis.Firstly,the requirement of emission current stability is clearly defined and common control algorithms are analyzed in feasibilility application in emission current stability. Combined with the controlled object characteristics,decide on using Fuzzy-PID algorithm and accomplish its functional simulation,and the digital closed-loop stability control of emission current is realised on the MCU.Secondly,after the analysis of the generation principle and detection influencing factors of ion flow signal,the improved Ⅰ-Ⅴ conversion method based on T-type resistor network is selected as an ion current signal detection scheme and switch of circuit transimpedance gain and multi-stage filter to suppress noise are designed,making the circuit measurement range from picoamp to microamp.The composite vacuum gauge overall test consists of test of ion current signal detection module circuit,stable emission current functional module circuit and the whole systems.Some conclusions can be drawn from the test results-the measurement range of ion current signal is 1pA to 6uA and its measurement resolution is 0.2pA and that its noise is less than 1.5mV.For ion gauge,the displaying values of emission current and the potential of accelerating electrode and the cathode to ground have an error less than±0.8% and so is with time stability.For resistance gauge,in the main measuring range from 1Pa to 103Pa, the displaying values have an error less than±10%.For ion gauge,in the measuring range from 10-8Pa to 10-1Pa, the displaying values have an error less than ±1%.The test results satisfy the national standards and meet the general requirements of vacuum measurement in industrial production and scientific research.更多还原