基于单片机的交流电机变频调速系统的设计__毕业论文设计

基于单片机的交流电机变频调速系统的设计

【摘要】本课题主要是研究电压型三相交流SPWM变频技术的基本原理、实现方法及软硬件设计，完成系统的软硬件设计。要求完成内容主要有：1、变频调速技术基本原理2、变频调速基本原理3、控制方案确定4、软件与硬件设计。涉及的主要相关知识：电力电子及运动控制、微机控制。在通常情况下交流异步电动机用作调速机时，它的控制电路复杂，系统的效率较低。采用单片机微机控制的交流异步电动机变频调速系统使起控制电路大为简化，使用正弦脉宽调制（SPWM）驱动，系统效率也有所提高。交流异步电动机的变频调速，实际中多采用脉冲宽度调制（PWM），完成调频和调压两种功能。用单片机实现（PWM）来控制可使调节灵活，电路简化。本设计采用的MCS51系列的单片微机控制PWM。

传统的交流变频调速系统由正弦波和锯齿波相交产生所需的脉宽调制波实现恒压额比的变频调速控制。这种系统由于采用模拟控制，设备复杂、调整困难，且控制精度低，可靠性差，因而限制了这种系统的应用。与上述传统的系统相比，本系统具有如下特点：采用新型大规模专用集成电路产生脉宽调制波，使波形稳定，精度和可靠性显著增加。以单片机8031CPU为核心的全数字控制．电路简单，调整迅速，进一步提高了控制精度。

【关键词】电压型三相PWM整流器；变频调速；单片机；交流电机

【A B S T R A C T】Focus is Studying SPWM three-phase voltage-type AC inverter with the fundamental principles in this paper, and designing the methods and software and hardware, and complete system software and hardware. The main completion on: 1.the basic principles of VVVF technology 2. the basic principles of Frequency Control, 3.the control scheme for the 4.software and hardware design. The main relevant knowledge: power electronics and motion control, computer control. Under normal circumstances in exchange for motor asynchronous speed machine, it's complicated control circuits, the system's efficiency is low. SCM using computer control the exchange of asynchronous motor Frequency Control System that has greatly simplified control circuit, the use of SPWM (SPWM) drive, the system has improved efficiency.

Induction Motor Frequency Control, in the actual use of pulse width modulation (PWM), and completed FM Surge two functions. To achieve single-chip microprocessor (PWM) to control can adjust flexibly, to simplify circuit. This design by the MCS51 series of single-chip microprocessor achives PWM control。

The traditional exchange of Frequency Control System from the intersection of a sine wave and the sawtooth PWM wave of constant pressure to achieve than the frequency for arrest control. As a result of this analog control system, equipment complex and difficult adjustment, and low-precision control, reliability poor, thus limiting the application of such a system. With the traditional systems, this system has the following characteristics: a new type of large-scale ASIC PWM wave, the wave stability, accuracy and reliability of a significant increase in SCM (8031 CPU as the core of digital control. Circuit simple to adjust quickly to further enhance the control accuracy.

【Key words】Three-Phase PWM voltage rectifier, Frequency Control, SCM, AC motor, computer control

目录

摘要 (1)

ABSTRACT (2)

第一章绪论 (4)

1.1 当前变频调速的发展状况及其趋势 (4)

1.2 设计本课题的总思路 (8)

1.3 设计任务及要求 (8)

第二章异步电动机变频调速 (9)

2.1 变频器 (9)

2.2 变频调速基本原理 (10)

第三章脉宽调制技术 (12)

3.1 相电压控制PWM (12)

3.2 线电压控制PWM (14)

3.3 电流控制PWM (15)

3.4 空间电压矢量控制PWM (16)

3.5 矢量控制PWM (16)

3.6 直接转矩控制PWM (17)

3.7 非线性控制PWM (17)

第四章系统的硬件设计 (18)

4.1 系统工作原理 (18)

4.2 主电路的设计 (22)

4.3 光电隔离电路 (26)

4.4 过电压保护电路 (27)

4.5 8051控制电路 (28)

第五章系统的软件设计 (30)

5.1 单片机程序设计 (30)

5.2 控制电路 (35)

5.3 最小脉冲问题分析 (35)

总结 (36)

参考文献 (37)