| With the rapid development of economy, the Living condition of people have been improved. however, there have emerged more and more serious problems consequently, such as car exhaust pollution and air pollution, limited resources such as oil, coal mining frequent and so on. We will face the energy crisis, and people’s living environment has become increasingly harsh. Solving the problem of the existing environment is dependent on the development of new energy. Solar energy as the new emerging clean has been widely used in economic and social. Presently, developing the electric car vigorously is one of the effective methods to solve the environment pollution and energy depletion. For the problem of electric vehicle battery power is insufficient and range is narrow, the method of solar assisted electric vehicle charging is proposed. Through researching and improving the efficiency of solar photovoltaic power generation system, the rapid development and promotion of electric vehicles can be promoted effectively.Firstly, the Structure and features of solar battery are analyzed. The mathematical model of the solar battery array is established. the model simulates Though the Matlab softwares, the output characteristic curve be showed.Secondly, according to the model characteristic curve, Solar cells on any two points in time of the output voltage and current is different, how to get every moment of maximum power output(product of voltage and current for maximum), the concept of maximum power point tracking is put forward. Based on the research of the maximum power point tracking algorithm and compares the advantages and disadvantages of the commonly used algorithm, a new algorithm is put forward. The new method combines the constant voltage and the perturbation method. Constant voltage of 0.75 times the Voc startup for disturbance voltage, combined with the variable step perturbation method to quickly find maximum power point. Though the commonly used algorithm is compared with, the advantages of the method is showed, such as fast, low hardware cost and easy to implement. To some extent, the disturbance of unstable faults is overcomed.Then, combining with maximum power tracking algorithm and comparing the commonly used solar energy maximum power point tracking hardware circuit. The BOOST circuit for DC/DC conversion circuit is selected and the parameters of the BOOST circuit is reasonably set. The battery charging characteristics is analyzed. Eventually, a three-stage charging method is choosed. The battery capacity utilization and the improvement of service life is realizes.Finally, according to the algorithm of maximum power point tracking of solar and DC/DC conversion circuit, the hardware circuit using STM8S103F3 single-chip as the core of the system is designed, including the BOOST circuit, battery charging circuit, protection circuit, DC voltage power supply module circuit, MCU control circuit and the man-machine interface circuit, etc. The single-chip microcomputer software program is programmed, debugged and simulated. The designed circuit of the system on field has been debugged and tested repeatedly. In the end, the expected results is achieved. Under the same temperature, light conditions, and electric vehicles equipped with maximum power point tracking, the performance of the solar battery charging system is tested, which is also compared with the uninstall solar panels. It is proved that the charging efficiency is improved using solar panels. The experimental results show that the use of MPPT controller of solar power system can be charging efficiency by 20 ~ 30% compared with traditional charging methods, and the actual charging efficiency up to 94%. According to the temperature and battery performance, the service life of electric car battery can be increased by 10% ~ 60%. |
PDF Full Text Request