基于PLC的加热炉温度曲线控制系统设计  

Design of Temperature Curve Control System of Heating Furnace Based on PLC

作　　者：魏艳红[1] 许昌[1] 王桂荣[1] 高雁凤[1] 

机构地区：[1]中国计量学院机电工程学院,杭州310018

出　　处：《计算机测量与控制》2015年第11期3635-3636,3640,共3页Computer Measurement &Control

基　　金：国家自然科学基金资助项目(批准号61203113)

摘　　要：对加热炉的温度控制过程进行了研究,提出一种控制系统的软、硬件设计方法;硬件上以PLC为核心,采用V/F转换器和PLC的高速计数功能实现了A/D转换,并利用PLC的定时器产生脉宽调制(即PWM)波形替代了D/A模块;软件上采用分段拟合的方法修正频率-温度曲线,弥补了常规PID算法的缺陷,实现了温度的闭环控制;降低了系统成本,实现了±1%的控制精度,满足了系统控制要求。Based on the research of control process of the heating furnace,the composition structure,the work principle and the soft design of control system for heating furnace are introduced briefly.In the system,the frequency signal is gotten from V/F converter used as an A/D（analog and digital）converter,and then it is sent to high-speed counter of PLC to measure the temperature of heating furnace.The PWM（pulse width modulation）curve produced by PLC are used to control the temperature of heating furnace as a D/A（digital and analog）converter.In the software design,the PID algorithm is applied to form a closed-loop control.Furthermore,the piecewise fitting method is used to make up for the defects of conventional PID algorithm by modifying the curve of frequency and temperature.Experimental results show that these method reduce the cost of control system via replacing expensive analog A/D module and D/A module,and also obtain better steady-state accuracy（±1%）and dynamic characteristics.

关 键 词：V/F转换 PWM PID算法 分段拟合 

分 类 号：TM571.61[电气工程—电器]