| Nowadays, the world is facing many social issues, such as severe energy situation, the ecological environment deterioration, etc. Adjusting the configuration of energy sources and developing green renewable energy was paid much attention seriously by every country in the world. The limited energy resources and restrict environmental protection requirements influenced the rapid growth of economic development for each country. Therefore, it is necessary and urgent to develop sustainable green renewable energy to meet the needs of the world economic growth. Solar photovoltaic power is inexhaustible in numerous green resources. It can be obtained expediently by sunlight and it has no pollution. Thus, photovoltaic power is an indispensible primary energy in the future.The process technology and equipment for monocrystalline silicon growth used in photovoltaic cell was researched in this thesis. Based on the in-depth understanding and analysis of mechanism of silicon crystal growth technical, the thermal field which used in the monocrystalline silicon furnaces and the automatic finishing process and procedure were researched. The following contents were the main points.1. The heat transfer manner during the monocrystalline silicon growth in furnace was studied and it can be controlledunder investigated conditions. Melt velocity and temperature fields derived silicon melt flow and heat conduction equations were figured out by studying FEMAG-Cz simulation software and finite element analysis and analyzing the control of liquid flow and heat transfer during the monocrystalline silicon growth.2. S-150-type monocrystalline silicon furnace hot field was analyzed and numerical simulation of steady-state thermal field was established. 24-inch thermal field was redesigned and a three-dimensional simulation graphics was built by using the thermal field simulation software based on current used thermal field. In this thesis, the power consumption was also calculated and analyzed according to the heat loss in the furnace during the monocrystalline silicon growth. According to the test results of new designed thermal field, it can save above 30% energy in the 8-inch silicon single growth when the growth speed was more than 1.2mm / min.3. By studying S-150-type monocrystalline silicon furnace programmable logic controller PLC and HMI control software, a control program of the automatic ending process was designed. There are two input variables in the diameter control system, one is the heating temperature and the other is pulling rate. While crystal diameter and growth speed are the two output variables. Input variables have coupling relationship with output variables. This design uses feed-forward compensation and diagonal matrix successfully resolved the silicon single crystal ending double into appearing in control, and the dual problem dual coupling system.4. In order to solve the problem of how to determine the balance of melt silicon during the silicon crystal growth process, it is established that a mass conservation equation based on the relationship of crystal quantity increase and melt silicon decrease during the silicon crystal growth process in the unit time t. Finally the problem was solved by Excel macro system design software according to this mass conservation equation... |
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