基于单片机的小尺度荷电燃烧控制系统

Control System Based on Single Chip Microcomputer for Small-scale Electrostatic Charged Combustion

面向小尺度荷电燃烧装置,设计了基于单片机的控制系统,并进行了控制实验研究。设计中采用了STC89C52芯片、步进电动机驱动芯片、数模转换芯片、MAX232电平转换芯片、液晶显示LCD1602和矩阵键盘等,构建了基于单片机和电压反馈的步进电动机控制系统。通过键盘输入相关控制参数,结合电压采样信号可以实时控制步进电动机,由步进电动机驱动旋钮调节高压直流电源,从而控制火焰燃烧状态。运用计算机与单片机之间串口实时采集数据的实验结果表明:当其他条件相同时,回路电流随着极距的减小而增大;当极距固定时,相同电压作用下,增大流量,回路电流增大。当微尺度喷管流量过大、电压过高时,空气扰动等都容易导致极板间放电,火焰跳跃甚至熄火。以检测的反馈电压作为反馈变量,与键盘电压设定值相比较,以步进电动机为执行器可实现对外加高压直流电源的快速调节,从而实现对燃烧系统的闭环实时控制。本研究为复杂的燃烧过程提供了简单的电学控制方法。

A control system based on single chip microcomputer was designed for small-scale electrostatic charged combustion equipment,and some experiments were carried out using the control system. The liquid ethanol was used as fuel and a glass capillary tube with inner diameter of 0. 9 mm was used as nozzle in the combustion experimental system. The external electric field system was composed of a high voltage DC power source,two copper plate electrodes with diameter of 50 mm,1 MΩ resistance and 5 n F capacity. The control system was based on a single chip microcomputer and a voltage feedback stepping motor,and a STC89C52 chip,a driver chip for the stepping motor,a digital to analog conversion chip,a MAX232 level switch chip,a LCD1602 display and a matrix keyboard were applied. The voltage sampling signals combined with the relevant parameters inputted from the keyboard were used to realtimely control the stepping motor. The high voltage direct current power source was adjusted by the stepping motor and then the combustion and flame could be controlled. Serial data and experimental results using real-time acquisition between personal computer and microcontroller indicated that the circuit current increased with the decrease of electrode spacing; and it decreased with the increase of flow rate of ethanol. Too big flow rate of ethanol,too high voltage,or air turbulence all caused discharge between the plates,flame oscillation or even extinction. The detected voltage was used as a feedback variable and compared with the set value inputted from the keyboard. The stepping motor was used as an actuator to quickly adjust the high voltage DC power. Thus,the real-time closed-loop control of the small-scale combustion and flame system was achieved.