Design Of Sun-tracking System In PV Grid-connected Power Generation

With the rising of world energy demands and increasing depletion of natural resources, energy suppliers, industrial companies and consumers have raised new challenges. On one hand, we should use energy as efficiently as possible; On the other hand, it is a trend to develop new energy. Solar energy is inexhaustible and bottomless. As one of the new green power, it attracts wide attention around the world. However, there are many factors of instability in the solar energy using. So how to use solar energy sustainably and efficiently has become an important field of solar power research.Based on the status of solar energy technology, this paper proposes a solar tracking control system used in grid-connected photovoltaic power generation to improve the use efficiency of solar energy.At the beginning, this paper describes the characteristics of PV solar cells and the movement laws of the sun relative to the earth, and designs this dual-axis sun-tracking system, which includes solar panels, microcontroller, DS1302 clock circuit, four-quadrant sensor, stepper motor and drive, transmission gear and power supply circuit. ATmage8 is chosen as the core controller. The trajectory tracking control fixes the early position and the sensor tracking control is designed for error correction. The main function of MCU is to convert the output information of DS1302 clock circuit and sensor to control signals, send them to the stepper motor drivers and control the movement of stepper motors. The main power supply includes switching power circuit, DC/DC circuit and lightning protection circuit. AC power removed from the electricity grid is changed into 24V DC power by switching power supply circuit, and supply power for the stepper motors and drivers. Besides, this system also designs other DC-DC circuits to supply different levels of DC power to for other control circuits. The lightning protection circuit is designed to protect the outdoor control system. This paper designs the relevant hardware and software parts completely, builds the experimental platform for sun-tracking system and makes real-time comparative experiments. The experimental results show that dual-axis tracking system runs stable. Compared to the fixed system, the solar panels generating capacity of dual-axis tracking system can be improved by 30%.