Design And Research Of Control System And Control Method For Three-zones Crystal Growth Furnace

With the rise of the information industry and the warm trend for the PV power generation by new energies, it has great demand to the big crystals with high quality, and this means higher requirements should be made to precisely control the temperature in which the crystal grows. Due to the characteristics that the three-zones crystal growth furnace has large delay and great inertia and strong coupling for the crystal growth, the PID controller, which has been commonly used in the industry due to its simple control and higher reliabilities, cannot achieve the satisfactory controlling effects. In view of this situation,This paper designs a kind of neural network PID decoupling of the three-zones crystal growth furnace.Therefore, this has great significances both in theory and practice.For the requirements of three-zones crystal growth furnace control accuracy,the paper uses the DSP chip TMS320F2812, which was made by TI company, as the hardware control core and CCS3.3 development environment as the software platform for both hardware and software design and development to achieve the three-zones crystal growth furnace control system functions. This paper has designed DSP lower machine and human-computer interface(touch screen). DSP lower machine control parts include:Three way temperature data collection, The generation of PWM waveform,serial data communication. Human-machine interface applications include: system control commands sending, three-zones temperature real-time display, data conversion and storage. DSP lower machine and man-machine interface (touch screen) complete temperature signal acquisition and analysis of three-zones crystal growth furnace and meet the technical requirements of the crystal growth process.After completing the system software and hardware design, in view of the three-zones crystal growth furnace and starting from the mechanism of heat conduction, establish simple mechanism model of the three-zones crystal growth furnace, and select model structure with reference to mechanism model characteristics. Grey box method is used to establish the system mathematical model. According to the three-zones crystal growth furnace temperature field distribution characteristics, design the control system with classic PID diagonal decoupling algorithm and neural network PID decoupling algorithm successively. Simulate the designed system with MATLAB, and the simulation result validated the design method has a good decoupling and self-learning control performance of multivariable strong coupling and time-varying objects, reached the requirement of the system control indicators.