文档介绍：摘要

绝缘电阻是设备安全要求测试中的一项重要指标,它可以判断绝缘体足否完整以及绝缘体表面是否被污染,通过测量设备的绝缘电阻可以及时发现设备普遍受潮、绝缘劣化和绝缘击穿等缺陷。原有的绝缘电阻测量设备是传统的兆欧表为主,其测量精度差,显示阻值低和无法一机多用等缺点限制了其使用范围。本文针对上述缺点,将高频高压开关稳压电源和PIC单片机控制引入到绝缘电阻测试系统中,实现测量的自动化和宽量程,使测试更加方便、准确、直观。
首先,本文对绝缘电阻测试仪的技术背景以及国内外的发展状况进行简要明了的介绍,并阐述本文主要研究的内容。其次,结合绝缘电阻测量中高电压,弱电流等特点,通过分析绝缘电阻测量误差的来源,决定以单片机为核心,使用加压测流法的测量方案。单片机主要完成采集和处理经过转化的数字量信号,完成键盘输入、液晶显示等功能。可根据设定值将12V供电电压分别输出500V--5000V不同档位的高压。论文中,分析了此高压模块的工作原理以及结构设计中应该注意的问题以及解决措施。在随后的电阻分压电路中,高压通过绝缘电阻和一个与其串联的标准电阻分压,分压后的电压信号经过射随器、AD7705转换器送入单片机,经过单片机处理后得到被测绝缘阻值并由LCD现实。在本文的后半部分,结合流程图对整个软件系统的设计思想和一些重要的信号处理程序作以阐述。整个软件系统是由c语言编写,共有四部分,分别是:液晶显示模块,键盘处理部分,模/数转换和数据处理部分。
本系统的最大特点是:
(1)采用高频DC/DC变换器逆变直流高压的高压电源具有体积小,稳定度高的特点,可有效提高仪表的检测精度。
(2)整个系统的测量范围宽、精度高,对应500V一5000V的测量电压,测量范围达20M--20000M,误差小于5%。
关键词: 绝缘电阻; PIC单片机; DC/DC变换器
Abstract
Insulation resistance(IR)is all important index in a testing of the safety equipment requirementand also is one of major parameters in judging whether insulations are in goodshape or stained on the of which a low accuracy,low displayed digital and In this system,a highfrequency high voltage switching regulated power supply and a single puter con—troller are introduced to realize an automatic measuring,a wide range and a high accuracy.
Firstly,this disquisition carries out a brief introduction on the domestic and develop situation as well as the technical background of IR tester,Secondly, error Sources, of high voltageand weak converter sup with a 12V Dvoltage can generate 500V-- author analyses the operating principle of DC/DC converter as well as elaborating someparticular problems to he noticed and corresponding method in the electrical and ,the HV produced from voltage—multiplying is dividedby the IR and another standard resistance connected with IR in series voltage follower and A/D converter tohe handled and displayed on LED. The whole ofsoftware is programmed with C language and is divided into four parts,a