The Temperature Control System Of Diffusion Furnace That Based On The Improved PID Algorithm

With the increasing trade protectionism to China, European Union and theUnited States in recently announced that they would levy antidumping duty andcountervailing duty on Chinese Photovoltaic products, that helps us do someself-reflection. Diffusion furnace is an important equipment for the productionprocess of solar cells.Face the fact that core technology for diffusion equipmentrely on foreign industry and solar products mainly rely on the foreign market, weshuld evolve the domestic market,at the same time, we should also strengthen theself-exploitation ability of the core technology for diffusion furnace, to to get ridof the dependence on foreign technology as soon as possible.This article makes a detailed analysis on the diffusion furnace processprinciple and temperature characteristic, improved the traditional PID control onthe basis of the thorough research on it. And the fuzzy PID control method is triedto introduce into the PID control system to improve the level of automation. Thisarticle designed a cascade control systems based on fuzzy PID, and simulated in thematlab environment. This system uses PLC programmable controller as the lowecomputer to control furnace temperature real-time, collect informations, andexchange date with the upper computer, the temperature control algorithmaccording to the actual situation of furnace temperature calculated reasonablecontrol parameters, then sent the control information to the actuator, actuatorchanged the SCR conduction angle to adjust the heating power to gain good controlover the furnace temperature. Finally, do process tests in experimental pipe ofdiffusion furnace to validate the the control performance of the system.