Digital Photovoltaic Cell Array Simulator Research And Design

Solar energy is paid more and more attention to as a new type of regenerated energy sources. But under the influence of the sunlight intensity and surroundings temperature, the cost of solar array experiments is too high and the cycle of research and development becomes too long. The solar array simulator can shorten the cycle greatly and improve the efficiency of investigation and the reliability of result.Firstly, the theme shows the exploitation and utilization of solar energy, then introduces the photovoltaic system and photovoltaic array, base on this, the theme introduces the study background, significance and the research conducted home and abroad on.Meanwhile, this paper introduces the principle of solar cell, shows the equivalentcircuit model of PV array, then analyzes the I-V, P-V output characteristics and the environment factor's affect on it. Then the mathematic model of the photovoltaic-array is built. This work is the base ofthe photovoltaic array simulator.Secondly, in the theme the half-bridge convertor has been selected as the topology of the main circuit. The theme also analyses its working principle in detail and introduces the design of acquisition circuit and the technology of IGBT module drive and protection circuit.Thirdly, this theme uses the TMS320F2812 DSP as the major controller of the simulator controlling circuit. This theme analyses theperforming characteristic and the advantages of that type of DSP, analyzing the hardware design of the single chip to realize the function ofdetecting and controlling, such as the AD transformation, the wave engender of PWM. This theme also researches the application of digital PID control in digital photovoltaic array.At last, the theme finally gives the different steady working point's experimental results of the simulator when working under the closed loop. The experimental results indicate that the photovoltaic-array's steady points tallies with the simulated I-V output curve of solar array and simulates their dynamic transformation when the load is changed.The PV array simulator's maximum open circuit voltage is 90V, maximum short circuit current is 3.5A and maximum power point output is 240W.When connected with the photovoltaic inverter, the inverter can track maximum power point exactly,and steadily.This experiment prove that the solar array simulator can be used in photovoltaic inverter,and providing an all-round test platform for the photovoltaic facilities.