电子负载设计论文

摘要

摘要

随着电力电子技术的、计算机技术和自动控制技术的迅速发展，为电源检测技术带来了革命性的变化。由于铁道电气化供电、电气牵引、信号控制、无线通信、计算机指挥调度中心及家庭日常生活等应用领域都在大量应用各种各样的电源，因此人们对电子负载的需求越来越多，对其性能要求也越来越高。而传统的电源检测技术面临着极大的挑战。为准确检测电源的可靠性和带载能力，因此把电力电子技术和微机控制技术有机地结合起来，实现电源的可靠检测。

本系统主要以89c51单片机为控制核心；设计恒流方式的电子负载，即无论电压如何变化，流过该电子负载的电流恒定，且电流值可设定。包括控制电路(MCU)、驱动隔离电路(PWM波)、主电路、采样电路、显示电路等；能够检测被测电源的电流值、电压值；各个参数都能直观的在数码管上显示。

关键词：电子负载；单片机（MCU）；数模（D/A）；PWM。

Abstract

With the power electronics technology, computer technology and the rapid development of automatic control technology for power detection technology brings revolutionary change. As the railway electrification power supply, electric traction, signal control, wireless communication, computer and family life control center applications such as a large number of applications in a variety of power supply, so people need more and more electronic load on performance requirements are also increasing. The traditional power detection is facing a great challenge. For the accurate detection of power supply reliability and load capacity, so the power electronics technology and computer control technology combined organically to achieve reliable detection of power supply.

System mainly 89c51 microcontroller to control the core; design constant current mode of electronic load, that is, no matter how the change in voltage, current through the electronic load current constant, and the current value can be set. Including the control circuit (MCU), drive isolation circuit (PWM wave), the main circuit, sampling circuit, display circuit, communication circuit, the keyboard scanning circuit.

Key Words: E-LOAD, SingleChip(MCU), Analog to Digital Convertor,Digital to Analog Convertor，PWM。

目录

摘要........................................................................ I Abstract ................................................................... II 1电子负载的原理及概述 (1)

1.1电子负载的意义 (1)

1.2电子负载的工作方式 (1)

1.2.1恒定电流方式 (1)

1.2.2恒定电阻方式 (2)

1.2.3恒定电压方式 (2)

1.3在本设计中要做的主要任务 (3)

2 系统硬件设计 (4)

2.1电子负载设计模块方框图 (4)

2.2单片机学习应用的六大重要部分 (4)

2.3 AT89C51单片机的应用 (6)

2.3.1 AT89C51单片机性能特点 (6)

2.3.2 AT89C51各引脚图及各管脚功能 (7)

2.4电源 (8)

2.4.1芯片介绍 (8)

2.4.2原理图 (9)

2.5 A/D转换器接口ADC0809 (9)

2.6系统显示模块 (11)

2.7电压、电流采样 (11)

2.7.1电压采样 (11)

2.7.2电流采样 (13)

2.7.3 MOSFET场效管的应用 (14)

2.7.4 集成运放的应用 (15)

2.8 系统保护电路的设计 (17)

2.8.1过流保护 (17)

2.8.2过压、短路保护 (18)

3 系统软件设计 (19)

3.1汇编程序设计概述 (19)

3.2 Keil开发软件介绍 (19)

3.3 ADC0809模数转换子程序设计 (20)

3.4显示子程序 (21)

3.5电子负载程序设计流程图 (22)

4 系统的可靠性设计 (24)

4.1硬件系统的可靠性设计 (24)