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Microwave technology is a new technology that has developed at the early 20s last century. At first, microwave was used for communications, later, microwave heating technology got more and more applications in the industrial. At present, China has been used microwave technology increasingly in the leather, wood, color printing, food, metallurgy, paper, chemicals, ceramics, pharmaceuticals, tobacco, and medical and other industries, and has achieved good economic results. Because the microwave is internal heating, the microwave heating of the material starting from the material elements, it can overcome the "cold center" in the material. So, microwave heating is fast, temperature distribution is uniform, and save energy, Compared to the conventional heating methods, microwave heating is more efficient. Because, the measure and control of the temperature during microwave heating is influences the efficiency of industrial production directly, therefore, design a convenient control, precision, stable control system has a high applied value.In this paper, AT89C52 microcontroller is center control unit. By controlling the voltage of the magnetron to control the power, so we can control the furnace temperature of the industrial microwave oven. PID is the most commonly used control algorithm in industrial production processes, PID control 85%～90%, with the development of science and technology, Especially the development of the computer. Many advanced PID control emerged, and has been widely used. This article uses PID control algorithm to design a closed-loop temperature control system. In this article, the frequency of the microwave heating control system is in the 2450MHz. The following major elements:1. Tell about the history of the development of microwave heating, the basic concepts and principles and characteristics of microwave heating. Describes the structure of microwave heating equipment, and the principle of every part.2. The setting of the temperature in the microwave heating process, the collection and display the target temperature. Collect the temperature by thermocouple, and convert the analog signals of millivolt into digital signals that come from the thermocouple by digital converter MAX6675,then send the digital signals into the AT89C52 microcontroller. 3. AT89C52 microcontroller get the manipulative quantity from the data by PID algorithm. MCU through pulse modulation and zero trigger thyristor voltage regulator technology, control the temperature of microwave oven. Tests show the results is satisfactory.4. The experiment shows the system step response curve, using Cohn-Coon formulas to determine the transfer function. Simulate and analyse the effect by Simulink.
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