Research On The Key Technologies Of Photovoltaic Power Generation System

In recent years, the green renewable energies are developing fast around the world. Solar energy, a clean and huge energy reserves one, is becoming a popular energy. Photovoltaic power is used mostly in various applications of solar energy. With the decrease in the price of PV modules and the development of power electronics technology, the photovoltaic power generation capacity and the convertor's efficiency are increasing while its size is decreasing. Higher requirements of the design and manufacture of the equipment of photovoltaic power generation system are called.In order to improve the overall efficiency of photovoltaic power generation system, this article chose the conversion devices as a research goal and did some researches on the key technologies of photovoltaic power generation—the maximum power point tracking technology of photovoltaic array. It did some major researches on the topology applicable to the maximum power point tracking convertor and on its control methods. Analyzing the principle and output characteristics of solar cells, this article introduced several maximum power point tracking algorithms based on the DC/DC convertor and their respective advantages and disadvantages. On the topology research, this article analyzed the advantages and disadvantages of the Buck and Boost and full-bridge circuits when they were applied in the photovoltaic power generation and summarized their best applicable power rating. Then it proved the correctness of Theoretical calculation by simulation. Discussed the feasibility of the application of soft-switch and three-level technology using in the photovoltaic power generation and detailed the convertor process of the phase-shift full-bridge ZVS DC/DC convertor. Through the theoretical analysis, this article designed a MPPT convertor using the PS-FB ZVS PWM DC/DC circle as a main circle. It built a medium and small-sized independent photovoltaic power generation system and gave the simulations and experimental results whose power losses were analyzed. It proved that the phase-shift full-bridge DC/DC convertor, as a convertor of the medium and small-sized photovoltaic power generation system, can achieve the maximum power point tracking of the solar photovoltaic arrays and at the same time can ensure the switch to achieve the soft switching so that the system's efficiency and power density were improved.