| Microwave heating to matter is a new kind of heating way. It has many advantages, for example, fast of heat, high efficiency of heat and well security of application, and so on. Therefore, Microwave heating has been used extensively in the laboratories of industry and science investigation. Temperature of matter in the heating processes is an important index, therefore the measurement of temperature is a very important problem in microwave heating. Thus it is very necessary to measure and control the temperature of heated matter. In this paper we will design a device to measure and control the temperature of heating matter.This paper designs a kind of automatic control system which the temperature of microwave heater is controlled by STC89C52 SCM(Single Chip Micyoco)and discusses the principle, hardware constructors, and software design of this system in detail. Major work is described as follows:(1) A structure of microwave heater'system has been designed. Base on characteristics of microwave heating, by theoretical analysis, the microwave heater's dimension in waveguide and heat-cavity has been optimized.(2) Automatic control circuit of temperature has been designed. Through infrared temperature sensors to measure temperature, temperature is displayed real-time using LCD of SCM. Temperature is controlled automatically by pulse modulation technology and zero trigger thyristor strategy.(3) Based on Fuzzy-PID controlling arithmetic, this paper designs automatic controller which has SCM as the principal part and can work intricate data processing and intricate control function. SCM gives out pulse signal to spring circuit and driving triac, so controls the temperature of system.(4) The Mathematical model is established by Cohn-Coon formula, and transfer function of system is confirmed. Base on the established model and fuzzy self-tuning PID, a large number of simulative experiments is done using SIMULINK tools. |
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