The Design And Research Of Solar Cell Simulator Based On Simplified Model And Intelligent Algorithm

With the problems of world’s energy depletion and environmental pollution becoming increasingly prominent, people have been explorating and developing the new energy for a long time. Solar energy and other clean energy hav e gradually become the focus of social concerntration, and the proportion of solar power generation is higher and higher. If we use the real solar cells for PV systemic development, the developmental process is easily influenced by natural climatic conditions, resulting in slow progress. The research and development of photovoltaic system uses solar cell simulator instead of real solar cells, which can not only reduce the cost of development, but also shorten the cycle of research and improve the efficiency of research. According to the solar cell simulator, the following researches are carried out in this thesis:(1) The structure and operating principle of solar cells is studied; The equivalent circuit and output characteristics of solar cells is analyzed; The exact mathematical model of solar cell is derived based on the equivalent circuit; Two kinds of simplified models of straight line fitting and curve fit ting are analyzed in the paper; The MATLAB simulation model is built by the mathematical model of photovoltaic cells, and the output characteristics of the solar cells under different conditions are analyzed, which provides a theoretical reference for the development of the system.(2) The selection principle of the main circuit topology is summarized in this paper; Through the analysis of the working principle of the BUCK circuit, BOOST circuit and BUCK-BOOST circuit, the circuit design scheme is determined to be BUCK-BOOST with wide output voltage range; According to the performance characteristics and the main technical indexes of this simulator, the circuit parameters are calculated by combining the critical condition of the circuit; The PSIM simulation software is used to simulate the main circuit, which verifies the rationality of the design of the main circuit.(3) The principle and characteristics of several common control algorithms used in solar cell simulator are analyzed. Aiming at the shortcomings of the traditional algorithm, this paper proposes a fuzzy PID control algorithm based on four l ine simplified model. The algorithm makes use of the difference between the load current and the reference current to control the duty cycle of the main circuit, which makes the output of the simulator be in accordance with the characteristics of the I-U output of the solar cell. TMS320F2812 is selected as the main controller and the performance characteristics of the DSP are analyzed in this paper. According to the controller and its peripheral circuit design, the methods of software design and program flo w chart are given.(4) In order to verify the rationality of the design of the simulator, a lot of simulation and experimental research are carried out on the simulator in this paper. The simulator’s static performance, the starting, load mutation and li ght mutation of the dynamic performance were analyzed in simulation circuit, which is established in MATLAB; Through the platform of the simulator prototype, the above performances of the simulator are tested, And the I-U characteristic curve of the solar cells is plotted, and the error is analyzed and calculated. The result of experimental comparison between this algorithm and traditional PID algorithm show that it is consistent with the theoretical analysis, and it prove that the simulator based on the four line simplified model and the fuzzy PID algorithm has the advantages of fast tracking speed and good stability. This simulator can replace the solar cells to complete the development of photovoltaic system.