（毕业论文）--基于虚拟仪器的电热水器温度控制系统—调压方案.doc

内蒙古科技大学 本科生毕业设计说明书（毕业论文） 题 目：基于虚拟仪器的电热水器温度控制系统—调压方案 学生姓名：戴宗娥 学 号：200440503107 专 业：测控技术与仪器 班 级：测控04-1班 指导教师：李文涛 教授基于虚拟仪器的电热水器温度控制系统——调压方案 摘 要 关键词：；； Virtual Device-Based Electric Water Heater Temperature Control System-Pressure Adjustment Plan Abstract Electric water heater is a water heater using electricity to heat water. Currently, with improving life of people, people’s environmental protection and safety consciousness increasing and developing of the electric power industry of China, electric water heater is becoming more and more popular among consumers and its use is popularizing increasingly. Currently, its main development direction is safety, energy efficiency, multi-purpose and intelligence. The thesis designs a PID algorithmic-based temperature control system for electric water heater by using LabVIEW8.2. The basic operating principle of the system is as follows: the temperature signal that is collected by a thermal resistance Pt100 is converted into the 0-10V voltage signal which is acceptable for a board through conditioning circuit, which is inputted into a computer by using simulative input port AI0 of the board PCI-6221. The LabVIEW program operating on the computer generates one pulse to be outputted to the digital output port P0.0 of PCI-6221 by analyzing and processing the inputted data to control the connection with controllable silicon chip and to further control the heating process of electric water heater. Key words: Electric Water Heater；Temperature Control ；LabVIEW；Data Acquisition 图2.1 电热水器温度控制系统整体方框图 2.1系统硬件设计 基于虚拟仪器的电热水器温度控制系统的硬件电路图如附录A所示，本图主要包括温度测量及调理电路，温度控制电路，一个过零检测电路。现分别介绍如下。 2.1.1温度测量及调理电路 温度测量及调理电路主要由温度传感器和信号调理两部分组成，用于对电热水器温度的检测及信号调理。 本系统采用铂热电阻Pt100做为温度传感器。 信号调理的作用是对温度传感器的输出信号进行滤波和放大以满足数据采集卡A/D输入端电气参数要求。 温度的测量和控制主要取决于温度测量精度，因此，为了保证精度，从硬件采用了三个方面的措施：测量中传感器的连接采用三线制方法选用高精度低漂移运算放大器OP07运算放大电路测量电路采用恒流源供电。 图2.2 温度信号调理电路 2.1.2 温度控制电路 本系统温度控制电路的硬件电路主要由隔离光耦、触发器及晶闸管等单元构成。 本设计选择的是调压方案。 把两个晶闸管反并联后串联在交流电路中，在每半个周波内通过对晶闸管开通相位的控制，可以方便