Development of Temperature Control System for Hyperthermia Based on PWM
- VernacularTitle:基于PWM的热疗温度控制系统设计
- Author:
Xianfeng LIU
;
Xuefei YU
;
Guangwen LU
;
Daming PENG
;
Jiaxi YU
- Publication Type:Journal Article
- Keywords:
DS18B20;
PID;
PWM;
silicon controlled rectifier
- From:
Chinese Medical Equipment Journal
2004;0(07):-
- CountryChina
- Language:Chinese
-
Abstract:
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.
