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毕业设计 多用户集中数字电度表 共44页，22819字
摘 要
本课题针对目前居民楼和公寓等用电户集中场所的电能计量现状和存在的主要问题，设计了一种多用户集中数字电能表。该电表可同时分别检测和记录多用户的有功电能，不仅具有结构紧凑、精度高、功耗低等优点，而且还可以分时段计量各用户的电能以提高电网利用率，达到避峰填谷的目的。基于这种电能表组成的远程自动抄表系统采用低压电力线载波进行底层数据的传输，通过通讯和计算机网络等技术自动读取和处理电度表数据。本文首先综述了电度表的发展和自动抄表系统的现状，并介绍了电能测量的基本原理，重点对∑-ΔA/D转换原理进行了分析。然后，论文对多用户电度表硬件电路的设计进行了阐述，包括电源电路、电能测量电路、存储器、时钟电路、显示器和键盘电路、译码电路以及用于电力线载波通信的发送、接收和耦合电路等。该电能表以单片机为核心，具有数据处理能力强，抗干扰能力强等优点。在软件上，主要介绍了主程序和多用户电能脉冲的采集、复费率计量、最大需量计量、数据显示和键盘扫描等子程序，并绘制了其工作流程图。该课题的研究为电能计量和数据管理提供了一种新的技术手段。这种基于新技术而研制的具有电力线载波抄表功能的多用户复费率电能表，将以其较高的性价比而值得推广使用。
关键词：数字电能表；多用户；单片机
Abstract
In accordance with the present situation of the main electricity measurement problems existing in the field where many power users are living together, such as residential area or student’s apartment, a kind of multi-user electronic energy meter has been designed in this article. This electronic energy meter can detect the active amount of electricity of many users. Besides its wide measuring range, high precision, and low power, it can measure different electricity for each user in different time section which will improve the running efficiency of the electric net by adjusting the unbalance station of power consumption. Based on this meter, the automatic meter reading system adopts the low voltage power line to carry data. At first, this paper summarizes the developing history and the present state of energy meter and automatic meter reading system, and introduces the basic theory of energy measurement. As an important part, the principle of ∑-Δ analog-to-digital conversion has been analyzed. Then, the circuits of this energy meter’s hardware are illustrated in this paper, such as DC power supply, energy measurement circuit, extended memory circuit, real-time clock, extended display and keyboard circuit, and decoder circuit, etc. The digital electricity meter based on chip microcomputer AT89C52.Which can reorganize and count the massive data and with big of anti-interference. On the software, the realization of the main program and the subprograms such as energy pulse acquisition, multi-rate measurement, max-power demand measurement, data dynamic display, and keyboard scanning, are introduced with some flow charts. Generally, the study on this topic will improve the electric energy measurement and management to a high level, and it is worthy of generalization.
Key Words：Electronic Energy Meter; Multi-user; Single-chip microcompute
目 录
第一章 前 言 1
第二章 电能测量原理 2
2.1电子式电能表的测量原理 2
2.1.1模拟乘法器的测量原理 2
2.1.2 数字乘法器的测量原理 5
2.2 ∑-ΔA/D转换器的原理 7
2.2.1 ∑-ΔA/D转换器的调制转换原理 7
2.2.2 经∑-Δ调制的连续波的∑-Δ码的获取 10
2.2.3 ∑-ΔA/D转换的非线性误差分析 13
第三章 多用户集中数字电度表的设计 15
3.1 系统硬件设计 15
3.1.1 电源电路 17
3.1.2 电能测量电路 18
3.1.3 数据处理系统 24
3.1.4 通信接口 28
第四章系统软件设计 31
4.1 电能脉冲采集 32
4.2动态显示和键盘扫描 34
第五章 抗干扰技术 36
5.1硬件抗干扰技术 36
5.1.1电源的抗干扰设计 36
5.1.2屏蔽 36
5.1.3隔离与耦合 36
5.1.4接地 36
5.1.5印刷电路板的设计 37
5.2软件抗干扰设计 38
第六章 结 论 39
参 考 文 献 40
致 谢 41
附 录 数据处理单元原理图 42