Design And Development Based On The Maximum Power Point Tracking Control Algorithm PV Charging System

With the further development of the global economy, the demand for energy of human is growing. And the reserved fossil energy represented by coal are limited, so in the foreseeable future it is about to run out. And with increasing requirements of people for living environment, the traditional fossil energy sources are increasingly unpopular for the serious pollution for the environment. Thus, the development of sustainable green energy is of great significance. Solar energy as a kind of sustainable utilization green energy is a very good replacement of traditional fossil fuels. Because the solar energy is widely distributed and hugely reserved, it has attracted attention from countries around the world. They had put a lot of money and manpower to develop solar energy technology. Of which photovoltaic technology research is most important. Photovoltaic power as an new environmental friendly power generation method can improve the living standards of people. And it also have the character of generation size casual, more construction time, maintenance simple, zero-emission pollution and many other advantages. It has received the strong support of governments and rapid promotion worldwide. In the photovoltaic power generation system, solar charge controller is the important part. And it has become one of the research hot spot.The output of PV is infected by light conditions and ambient temperature and with a very complex nonlinear character. So in the process of photovoltaic power generation, we need the controller to track the maximum power output, improve the charging efficiency of photovoltaic cells, decrease the cost of power generation. This paper designed a model of solar charge controller based on STM32, which has a maximum power point tracking function. At the same time, in order to prolong the service life of the battery, we take the intelligent charging ways. The main contents of the content are as follows:1. The paper researched the domestic and abroad status and the development trend of the solar charge controller and battery charging algorithms. And then analyzes the equivalent circuit of photocaltaic cel, establishes the mathematical model, does modeling and simulation on the Simulink platform of Matlab software. At last analyzed the relationship between the output characteristics and the light intensity of the photocoltaic together with temperature and other factors.2.This paper finishes the overall function design of the hardware system and software system of the solar charge controller. It respectively analyzed the overall design scheme of hardware system and software system. It analyzed several kinds of common MPPT algorithm and put forward a variable observation method based on the variable step. At the same time, in the whole charging link, it designs the intelligent charging method based on the four stages of charging process: preliminary charging, maximum power charging, over charging and float charging.3. This paper introduces the hardware part of solar charge controller in detail. And it analyzes the topology structure of the main circuit and the type selection of the main components. And it introduces the power supply circuit, MOS tubes, voltage and current sampling circuit, protection circuit, etc in detail.4.This paper introduced the software part of solar charge controller in detail, which mainly can be divided into two parts: the MCU side and PC side. The software of singlechip processor is the development control procedures based on STM32. Which includes the charging control procedures, voltage and current sampling program, the realize of program based on disturbance observation, PID controller program, the display program of GPU serial screen. The PC software is a data acquisition program based on the C# develop program. The data mainly includes some related parameters of prototype debugging process. The work with MCU is realized by the serial port communication tool.Finally, we achieve some relevant experiment study which is based on the platform designed with STM32. We do experiments on the intelligent charging control strategy and the MPP algorithm. The experimental results show that the improved algorithm not only can quickly track the maximum power output but also make the oscillation amplitude near smaller which greatly reduced the output loss of the photocaltaic cell. Within its help we achieve the expected design purpose.