我的论文

西 北 工 业 大 学

硕 士 学 位 论 文

（学位研究生）

题目：基于PIC单片机和CPLD的GIS内置电子式电流互感器设计

作 者： 孙剑平 学科专业： 电路与系统 指导教师： 于海勋

2007年 3 月

西北工业大学硕士学位论文 摘要

摘 要

一种基于现代光电技术、半导体技术和计算机技术的电气测量新方法现在正逐渐应用到电流互感器的产品设计之中，采用此方法的电流互感器称为电子式电流互感器（ECT）。它是老式的电磁式电流互感器理想的更新换代产品，有一系列的技术优势，主要表现在：以光隔离绝缘、体积和重量大幅度减小、量程大范围扩大、较强的抗电磁干扰能力、信号用数字传输和处理。于是，对电子式电流互感器的研发已成为一个潮流。

本文讨论的是GIS内置的电子式电流互感器样机的研究与设计。参照电子式电流互感器的国际标准《IEC60044-8》和国外相关产品的成功设计，本文以PIC单片机和CPLD器件作为控制核心，分别对该电子式电流互感器样机的一次侧和二次侧进行了模块化设计。精度是样机技术指标的核心，为了实现测量级0.2的精度指标，低功耗的设计方法贯穿于整个设计的始终，包括优化器件选型及数据帧的编码方案等。

本文将三相电子式电流互感器一次侧的合并采集单元划分为传感头、数据采集板、合并通信板、发射板几个独立的模块，对各个模块进行了单独的软、硬件设计，其中三相的传感头和数据采集板的结构和电参数都是统一的，便于互换和查错。在传感头部分，比较了几种常用的传感头的结构方案，进行了性能分析和取舍；在数据采集板部分，分析了其需要达到的功能，并由此进行了器件的选型，包括PIC单片机和ADC芯片的选择。随后介绍了PIC单片机及其集成开发环境MPLAB IDE的特点和使用，给出了数据采集板的软件流程图；在合并通信板部分，选择EPM3256A器件作为控制核心，介绍了其性能特点及其开发平台Quartus II的使用。按照数字系统的自顶向下的设计方法对合并通信板进行了软、硬件的配置，同时也制定了合并通信板与数据采集板的通信规约和三相数据帧的编码方案。在二次侧的信号分配单元则主要讨论了针对单相数据帧编码的信号还原及调理电路的软、硬件设计和工业以太网电路构成。

本文随后运用Proteus仿真软件和Quartus II 5.0平台对文中的主要模块分别进行了硬件仿真、软件仿真和软、硬件的协同仿真，最后对样机进行了单相测量级准确度测试。这些仿真和单相的测试结果表明，该样机满足了预期的技术指标，也证明了本文的软、硬件设计是成功的、性能优良的。

关键字： 电子式电流互感器，PIC单片机，CPLD，低功耗，Proteus仿真

I

西北工业大学硕士学位论文 Abstract

Abstract

One new electric measurement method based on the modern photoelectricit technology，semiconductor technology and computer technology is applied to the product designing of current transformers gradually. It’s called electronic current transformer(ECT) which adopts the method. It’s the ideal update of old electromagnetic current transformer and has a series of technical advantages such as light insulation, decrease on volume and weight at large, great enlargement of measurement scope, good ability of EMC and digital transmission and processing. Thus, it has become a tide to devise ECT.

In this paper, the designing of the ECT’s sample machine built in GIS is discussed. PIC microcontroller and CPLD are chose to act as the controlling core and modularized design of the ECT’s primal side and secondary one is processed according to ECT’s international standard-《IEC60044-8》and overseas related products’ successful design. Precision is the quick of the machine’s technical targets. So the design method of low power consumption runs through the entire design all along including optimizing chip selection and data frames’code scheme to fulfill the precision target of test level 0.2.

In this paper, the merging acquisition unit at three-phase ECT’s primal side is divided into several independent modules, namely sensor, data acquisition board, merging communication board and transmission board, whose hardware and software are devised separately. The structure and electrical parameter of three-phase sensor and data acquisition board are uniform so as to interchange and check error easily. In the part of sensor, several schemes are compared in performance and then the final choice is made. In the part of data acquisition board, the related chips including PIC microcontroller and ADC are chose according to the board’s required function. Then the characteristic and use means of the PIC microcontroller and its integrated development environment-MPLAB IDE are introduced and the software flow chart is showed. In the part of communication board, the chip of EPM3256A is chose as the controlling core. Then its characteristic and the use means of its development environment-Quartus II are introduced. The board’s hardware and software are configured according to digital system’s top-to-down design method. Simultaneously, the communication agreement between the board and data acquisition board as well as the three-phase data frames’code scheme is made. As to signal distribution unit at the secondary side, the signal reverting circuit which deals with single-phase data frames’code scheme and the industrial Ethernet circuit structure are discussed.

In this paper, the hardware simulation, software simulation and coordinated simulation of hardware and software of some major modules are processed separately. In the end, the sample machine’s single-phase test level precision is tested. The simulation and test result show that the sample machine fulfills expected technical targets and that the design in the paper is successful and of high quality.

Key words: ECT, PIC microcontroller, CPLD, Low power consumption, Proteus

simulation

II

西北工业大学硕士学位论文 目录

目 录

摘 要............................................................. I Abstract........................................................... II 目 录............................................................ III 第一章 绪 论....................................................... 1

1.1电流互感器在电力系统中的作用................................. 1 1.2电流互感器的发展方向-电子式电流互感器........................ 1 1.3 GIS内置电子式电流互感器的结构方案........................... 2 1.4 本课题的研究意义 ............................................ 2 1.5 本论文的内容安排 ............................................ 3 第二章 电子式电流互感器设计中运用的新兴技术及器件................... 4

2.1 低功耗设计方法 .............................................. 4 2.2 嵌入式设计思想 .............................................. 5 2.3 自顶向下的设计方法 .......................................... 5 2.4 PIC单片机................................................... 7 2.5 CPLD ........................................................ 8 第三章 电子式电流互感器的硬件电路设计.............................. 10

3.1 合并采集单元的硬件设计 ..................................... 10

3.1.1 传感头电路............................................ 11 3.1.2 以PIC16F873A为核心的数据采集板电路................... 15 3.1.3 以EPM3256A为核心的合并通信板电路..................... 21 3.2 信号分配单元的硬件设计 ..................................... 24

3.2.1 以PIC16F676为核心的信号还原及调理电路................ 25 3.2.2 工业以太网接口电路讨论................................ 28

第四章 电子式电流互感器的软件设计.................................. 31

4.1 合并采集单元的软件设计 ..................................... 31

4.1.1 数据采集板软件........................................ 31 4.1.2 合并通信板软件........................................ 34 4.2 信号还原部分的软件设计 ..................................... 39 第五章 仿真及测试结果.............................................. 41

5.1积分电路的硬件仿真.......................................... 41 5.2 数据采集板的软件仿真 ....................................... 44 5.3 合并通信板的软、硬件协同仿真 ............................... 45 5.4 单相测试结果 ............................................... 47 第六章 结束语...................................................... 49

III

西北工业大学硕士学位论文 目录

参 考 文 献........................................................ 50 硕士期间参与的科研工作及发表的论文................................. 52 致 谢............................................................. 53

IV

本文来源：https://www.bwwdw.com/article/rrd2.html