Study On Data Acquisition And LCD Display System Of5kW Photovoltaic Inverter System

With the exhausting of the non-renewable energy resources, more and more country are carrying great weight on the clean solar energy. Because the photovoltaic system is vulnerable with the rapid change of illumination radiation. The output current of solar panels is unstable. In order to make the solar energy run safety and stable, we need to design a system to acquisition data and protect the the circuit. The embedded ARM processor has the quality of high performance、low power consumption and low cost. The embedded system combines with specific application and run operation system to make the system more flexible and effective. So a data acquisition and display system base on ARM processor is designed.Firstly this paper introduces the development of the photovoltaic power generation. Then the back-propagation neural network was adopted to establish the power prediction model. This module use the illumination intensity and the temperature as the input. This system is used to acquisition the data of illumination intensity and the temperature. Then specifically describe the hardware design of the data acquisition and display system, including the auxiliary power module、 temperature acquisition module、illumination intensity module、communication module and LCD display module.After that the paper describes how to set up the software platform with Linux operating system and establish The embedded cross-compiling environment. Then I transplant the loading program U-boot、Linux kernel and root file system to make the system to run U-boot program on Flash while powered on. The U-boot would copy the kernel to RAM, and jump to invoke the kernel which would in charge of managing and scheduling process. The Linux kernel can realize the preemptive scheduling to speed up system respond. The root file system provides connector of user application.Then the using of bus、device、driver module to design driver program is presented. The driver not only provide the invoking interface but also control the hardware. Because the traditional bitmap font cannot zoom in or zoom out freely, This paper adopts Freetype vector font to show words on LCD screen. It can enlarge or narrow the words freely and make the words seen beautifully and fully without sawtooth phenomenon.The embedded data acquisition and display system is generality、portability and instantaneity. It is widely used in data acquisition field of photovoltaic system.