基于PWM的热疗温度控制系统设计  

Development of Temperature Control System for Hyperthermia Based on PWM

作　　者：柳先锋[1] 余学飞[1] 卢广文[1] 彭达明[2] 遇家希[1] 

机构地区：[1]南方医科大学生物医学工程学院,广州510515 [2]南方医科大学附属南方医院,广州510515

出　　处：《医疗卫生装备》2008年第7期13-15,共3页Chinese Medical Equipment Journal

基　　金：广州市科技攻关计划项目(2007Z3-E0341)

摘　　要：目的:研制一种用于盆腔炎治疗仪的热疗温度控制系统。方法:采用基于单片机的PWM方法控制温度。系统由加热丝加热,在整个周期T内加热丝加热时间随系统温度不同分3个不同阶段:在温度较低时,加热丝加热的占空比为100%;在系统温度进入到一定阶段时,将所需温度和当前温度的差值经PID算法获得一个控制量,由该控制量来决定加热丝加热的占空比,系统温度越是接近所需温度,加热丝加热的占空比越是接近于0;若系统温度超过预定值,则整个周期加热丝不加热。结果:系统温度控制精度达到±0.2℃,超调为±0.3℃,响应时间为500s。结论:本方法温度控制精度高,超调较小,响应时间适中,能满足治疗仪热疗的恒温要求,且简单易行,成本较低。Objective To develop a hyperthermia temperature control system for the treatment of pelvic inflammatory disease. Methods Temperature was controlled by using PWM method based on a single chip computer. The system was heated by using heating wire. In the whole cycle of T, the heating wire＇s work time was divided into three different stages according to different temperature of system： in the lower temperature, the duty cycle of the heating wire＇s work time was 100%; when the system temperature entered to a certain stage, a control variable was obtained through the PID algorithm which was used to compare the difference between the current temperature and the temperature requirements. The control variable determined the duty cycle of the heating wire＇s work time ： the more close to the temperature required for the temperature of system, the duty cycle of the heating wire＇s work time was more close to 0; if the temperature exceeded a predetermined value, then the heating wire would not heat in the whole cycle.Results The accuracy of the temperature control system was ±0.2 ℃, the overshoot of the temperature control system was ±0.3 ℃, and the response time of the temperature control system was 500 seconds. Conclusion The temperature control method has high precision, small overshoot, and the right response time, which can meet the requirements of constant temperature of hyperthermia treatment. Besides, it is simple and cheap.

关 键 词：DS18B20 PID PWM 可控硅 

分 类 号：TP273.5[自动化与计算机技术—检测技术与自动化装置]