数字式直流电机双闭环调速系统设计

毕业设计（论文）

摘 要

在高度现代化的今天，现代电力电子技术、计算机技术、现代控制理论的发展，促进了直流调速技术的进步，使之成为目前活跃的调速技术。长期以来，直流电动机因其具有调节转速灵活、方法简单、控制性能好等特点，应用在越来越广的领域中。

在控制领域中，微机技术得到了广泛的应用。例如，以单片机为控制核心的直流电机调速系统。其调速系统的特点是：

1、速度给定和测速采用数字化，这样就能够在很宽的范围内高精度测速，进而扩大了调速范围，提高了速度控制的精度。

2、硬件高度的集成化，使零部件的数量和触点大大减少。

3、由于许多功能都是由软件来完成的，所以使硬件得以简化，故障率比较小。单片机以数字信号来工作，其控制手段方便灵活，抗干扰能力强。

本文以80C196KC单片机为控制核心，研制了一套数字式直流电机双闭环调速系统。介绍了如何从直流电机调速系统的功能和特点，分析双闭环PID控制的调速系统的数学模型，确定了电流环和转速环的比例和积分系数。此外，由于系统采用数字式速度给定和数字式测速方法，进而提高了速度控制的精度。

关键词：直流电动机；调速；PID 控制

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毕业设计（论文）

Abstract

At a height of the modernization of today，the development of modern power electronics, computer and modern control theory promotes the progress of DC speed regulation technology. For a long time, DC motor has made them to be used in many areas because of its neatly adjust, easy method and its control performance is very good.

With the development of microcomputer, it is widely used in the control field. For example, The digital speed control system for DC motor，which uses Single Chip Micro (SCM) as its processor. Its speed regulation system's characteristic is :

First、the speed giving and speed measuring adopt digital method，the system can measure the speed accuracy within a wide range，which expands the speed control scope and entrances its precision.

Second、the hardware is highly integrated，tire number of the parts and contacts of the system are sharply minimized.

Third、as most functions are carried out by software，the rate of malfunction is less than the Analog System. Moreover，as SCM works with digital signal，its control method is flexible and its ability to anti-interference is very high.

In this paper， a 80C196KC SCM is used as the processor for the speed control system of DC motor. It is also discussed in this paper how to analyze the math model of double- close- loop speed control system by analyzing the functions and characteristics of the speed controlling system for DC motor，and find out the proportion and integral factors of the current and voltage loop. Moreover，the system adopted digital speed measuring method to enhance the accuracy of speed control.

Key Words：DC motor;speed control;digital PID Control

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毕业设计（论文）

目 录

摘 要 ............................................................................................................................... 1 Abstract ..................................................................................................................................... 2 引 言 .................................................................................................................................. 1 1 概述 ....................................................................................................................................... 2

1.1 课题的背景 ............................................................................................................... 2 1.2 课题的实际意义 ....................................................................................................... 2 2 系统方案论证和总体结构设计 ......................................................................................... 3

2.1 调速方案的选择 ....................................................................................................... 3

2.1.1 系统控制对象的确定 .................................................................................... 3 2.1.2 电动机供电方案的选择 ................................................................................ 3 2.2 总体结构设计 ........................................................................................................... 4

2.2.1 系统结构选择................................................................................................. 4

3 数字式直流调速系统的硬件设计 ..................................................................................... 6

3.1 控制系统的硬件设计 ............................................................................................... 6

3.1.1 80C196KC单片机 ........................................................................................... 6 3.2 同步信号电路 ........................................................................................................... 7 3.3 触发脉冲输出电路 ................................................................................................. 10 3.4 显示电路.................................................................................................................. 11

3.4.1 LCD 液晶显示简介 ...................................................................................... 11 3.4.2 LCD 接口设计............................................................................................... 14 3.5 速度给定电路 ......................................................................................................... 14 3.6 看门狗MAX813L ...................................................................................................... 15

3.6.1 MAX813L芯片及其引脚 ............................................................................... 15 3.6.2 硬件电路图 ................................................................................................... 16 3.7 通信接口设计 ......................................................................................................... 17

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毕业设计（论文）

3.7.1 RS-232C通信接口标准 ............................................................................... 18 3.7.2 通信接口电路............................................................................................... 18 3.8 脉冲信号反馈模块 ................................................................................................. 19 4 直流调速系统的软件设计 ............................................................................................... 20

4.1 光电编码器测速的软件设计 ................................................................................ 20 4.2 显示模块的软件设计 ............................................................................................. 24 4.3 触发脉冲的软件设计 ............................................................................................. 24 4.4 主程序的设计 ......................................................................................................... 26 5 主电路设计与参数计算 ................................................................................................... 27

5.1 整流变压器的设计 ................................................................................................. 28

5.1.1 变压器二次侧电压U2的计算 ..................................................................... 28 5.1.2 一次、二次相电流I1、I2的计算 .............................................................. 28 5.1.3 变压器容量的计算 ...................................................................................... 28 5.2 晶闸管元件的选择 ................................................................................................. 29

5.2.1 晶闸管的额定电压 ...................................................................................... 29 5.2.2 晶闸管的额定电流 ...................................................................................... 29 5.3 直流调速系统的保护 ............................................................................................. 29

5.3.1 过电压保护 ................................................................................................... 30 5.3.2 电流保护 ....................................................................................................... 31 5.4 主电路及保护电路图 ............................................................................................. 31 6 数字式直流电机调速系统的数字PID控制 .................................................................. 32

6.1 PID控制原理 .......................................................................................................... 33 6.2 位置式PID控制算法 ............................................................................................. 34

6.2.1 直流电机的数学模型的建立...................................................................... 36 6.2.2 转速、电流双闭环调速系统的分析 ......................................................... 38 6.2.3 比例、积分系数初值的确定...................................................................... 39 6.2.4 采样周期T的选定 ...................................................................................... 40

结 论 .................................................................................................................................... 41

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毕业设计（论文）

参 考 文 献 .......................................................................................................................... 42 附录A..................................................................................................................................... 43 致 谢 .................................................................................................. 错误！未定义书签。

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