| Since the two oil shocks during 1970s, countries all over the world come to realize the crisis of traditional fossil energy and the pollution to the environment such as the greenhouse effect. The people now pay more and more attention to clean and renewable energy such as solar energy. Great governments'support has been given to photovoltaic power generation in recent years, and now it has achieved rapid developments. BIPV (building integrated photovoltaic) technology is an important branch of photovoltaic power generation, and has received the extensive attention because of the efficient use of urban space for photovoltaic power generation. In the same time of the development of new energy, energy saving is also an effective way to relieve the energy shocks. According to the above situation, an electrical energy storage system based on super capacitor in the construction of Photovoltaic building has been proposed in this paper. The system can not only have an efficient use of Photovoltaic power generation which is a kind of the distributed power generation in the building, but also realize the recycling of renewable power to save the energy of the building through the management of electric power.MPPT algorithm of photovoltaic power generation subsystem in the electrical energy storage system was been studied, and the electrical structure of photovoltaic system was been put forward at first, which is suitable for electrical energy storage system. This structure can reduce electric power loss and power transmission loss caused by the photovoltaic battery's mismatch. And then the paper has done the research on the MPPT control algorithm of photovoltaic power generation and DC/DC converter in the structure.Based on the analysis of the common basic MPPT algorithm, P&O arithmetic was been chosen as the basic algorithm of MPPT and a improved algorithm of P&O arithmetic is proposed. This paper proposed the direct current P&O arithmetic according to the output characteristics of DC/DC converter in the electrical energy storage system. This arithmetic simplifies the P&O arithmetic by cutting the voltage transducer, so the cost of hardware is decreased.This paper proposed the coefficient step-change P&O arithmetic .This arithmetic can increase the tracking speed by increasing the step size stage by stage before the system achieves the maximum power point(MPP), and improve stability by decreasing the step size stage by stage when the system achieved the MPP.This paper proposes the environment estimate P&O algorithm which can avoided the errors of the P&O algorithm in the process of tracking by estimating influence of the environment changing to the output power. Combining with the three improvements, this paper gets the environment estimate and coefficient step-change and direct current P&O arithmetic algorithm which overall improves the performance of the disturbance of observation and makes it more applicable to BIPV system, and improves the system efficiency BIPV.The hardware and software on the DC/DC converter was been designed. In the hardware, this paper used in Cuk-ZVT-PWM circuit to improve the efficiency of the switch tube; In the software, this paper set the upper and lower limit of the variable step according to the actual situation, and designed the main program安and MPPT procedures and PWM happen program. In the end, this paper completed the joint commissioning, proves the rationality of the design of this paper, and testes the MPPT efficiency and converter efficiency of test machines. |
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