Research On Photovoltaic Charging System For Electric Vehicles

The electric vehicle on-board photovoltaic power generation system can use an independent photovoltaic system to charge the electric vehicle.This method will greatly utilize solar energy to provide electric energy for the electric vehicle and increase the endurance of the electric vehicle.At present,the independent photovoltaic system technology has been relatively mature,and the functions that can be realized are also comprehensive,including functions such as over-current protection,charge detection,temperature compensation,and charge control for maximum power point tracking.The main research hotspots of the current research are to improve the research on solar energy utilization rate,the charging strategy research of the controller,and the monitoring research of the state of charge.In order to be able to apply the photovoltaic system reasonably and safely to electric vehicles,basic research was carried out before the research and design system.The power generation efficiency of photovoltaic cells under different light intensities was studied through experiments,and the simulation model of photovoltaic cells was established to study the outside world.Temperature and light intensity affect the output characteristics of photovoltaic cells,and the charge controller and battery management controller are designed.The main contents include:(1)In order to study the power generation efficiency of photovoltaic cells under different illumination angles,a basic research on independent photovoltaic charging systems was carried out,and a test platform was built.The test platform is divided into hardware part and software part.The hardware part includes: STM32 single chip microcomputer,a 18V/5A photovoltaic panel,charging controller,12V/200 AH lead-acid battery;the software part uses Labview software to realize data conversion.Real-time data storage.The programming software of the MCU is Keil,the programming software is FlyMCU,and the language used is C language.The output characteristics of the photovoltaic cells under different illumination angles,different external ambient temperatures and different illumination intensities were designed to lay the foundation for the application of independent photovoltaic systems on electric vehicles.(2)Developed various functional modules of the controller to realize over-current protection,SOC state-of-charge monitoring,MPPT charging control,and data acquisition.The charging control mode selects the control charging mode of MPPT.The algorithm adopts variable step size perturbation observation method.The algorithm can flexibly and accurately track the maximum power point of photovoltaic cells,effectively reduce power oscillation and reduce the charging loss of photovoltaic cells.The SOC state of charge monitoring can monitor the capacity of the battery in real time.The algorithm is selected as the Anshi algorithm.The algorithm is simple and easy to implement.The remaining power of the battery can be monitored in real time through the program setting.(3)After the control system is completed,the validity of the MPPT algorithm is verified by simulation,and the duty adjustment of the PWM is tested.The trajectory is drawn for the MPPT maximum power point tracking.The independent photovoltaic system equipment was installed on the electric vehicle for charging test,and the independent photovoltaic system was used to charge the electric vehicle.