The Tunnel Microwave Heating System Of DSP-based Control

Using tunnel microwave heating equipment, we had redrying experiments on tobacco. With the need of fast and accurate measurement of the materials'temperature in the tunnel microwave heating control system, We used the non-contact temperature measurement devices (Infrared Temperature Measurement Device).It effectively solved the temperature measurement delay phenomenon of the traditional tunnel microwave heating equipment, and greatly reduced the effect of temperature sensor on the temperature field of measured object, achieved the precise measurement of the temperature. It provided an important control condition for the real-time temperature(T₁,T₂) measurement of import and export materials, and the real-time on-line control for tunnel microwave heating equipment.We used the AC variable speed meathod(ASD) of direct torque control (DTC).But there are some problems in the meathod, such as torque error, flux error, and torque, flux, current pulse in the steady running. So we introduced the fuzzy logic control to the conventional induction motor direct torque control strategy. It used fuzzy controller to replace the torque and flux Bang-Bang controller of the traditional direct torque control, and optimized the choice of space voltage vector. It not only improved the robustness and rapid of the control system, but also displayed the technology of traditional DTC, and weakened the system buffeting effects.According to the real-time on-line control theory of microwave heating equipment, the direct torque control principle, and the fuzzy theory, we constructed the induction motor direct torque control model from the fuzzy model. According to the performance comparison between traditional DTC and fuzzy DTC of MATLAB simulation, we made a conclusion that the performance of direct torque control is superior. We built the fuzzy induction motor direct torque control system at the core to TMS320F2812.Experimental results showed that the temperature measurement and torque control achieved the expected design requirements.