Research On Photovoltaic Generation System Using Automatic Solar Tracking

With the reduction of the traditional fossil energy reserves, many countries and regions begin to pay more attention to the research and application of new energy sources. Because of the solar energy has the advantages of abundant reserves, wide distribution, low cost, fossil energy does not have, solar energy is gradually becoming a hot research topic. But it also has the disadvantages such as weak radiation intensity, low stability and intermittent, how to improve the utilization rate of photovoltaic power generation system has become one of the main problems in the field of solar energy utilization.Aiming at the problem of low efficiency of photovoltaic power generation system of solar energy utilization, this paper presents a two-axis solar tracking method,and the following aspects of the work are done.(1) The necessity of the sun tracking system. First, this thesis analyzed the necessity of sun tracking and the operation paths of the sun, calculated the theoretical value of moving trajectory of the sun and verified the value. Meanwhile, this thesis compared the solar trajectory tracking and photoelectric tracking modes, and the advantages and disadvantages of these two methods are summarized.(2) Research on the solar tracking scheme. By combining the merits of both tracing methods, the two-axis sun tracking control system was selected for the sun-tracking system.(3) The design of system. On the basis of the two-axis solar tracking control system, this paper analyzed the functions of tracking systems and presented specific strategies of tracking systems. At the same time, the solar trajectory tracking and the photoelectric tracking method are used in the tracking loop.(4) Hardware selection of control system. The control system used PLC as the core controller. The hardware includes computers, PLC, photovoltaic electricity generating modules, stepper motor driving machines and photoelectric detection devices. For the stability of the system, the motor parameters of the load inertia and the step motor are calculated, and the suitable step motor is selected according to the calculation results.(5) The design of the software part. The software includes sun tracking main control program, the solar trajectory tracking and photoelectric tracing program. The SIEMENS S7-200 series PLC programming software Step7-Micro/WIN32 as the development platform, design the program.(6) Experimental verification and result analysis. To verity effects of tracking system, the fixed installation mode will be compared with the two-axis tracking mode in the comparative experiments. The results show that the generating efficiency of two-axis devices is more than 30% than that of fixed installation devices. The two-axis tracking control system designed in this thesis has a good effect and can efficiently improve the utilization ratio of sun power in the photovoltaic power system.