Research On The Response Characteristics And Conversion Efficiency Of Photovoltaic Cells In Laser Wireless Energy Transfer

Laser wireless power transmission means using laser as energy transmission carrier instead of using energy transmission line,to provide energy to a machine from a long distance.Compared with the traditional energy transmission method,the laser wireless power transmission has the advantages of long transmission distance and high transmission power density,so it can be used in the space solar power station,and can also be widely used to provide energy from a long distance to UAV,satellite,space vehicle,space base,robot working under extreme conditions and so on.At present,the main limit of the laser wireless power transmission system is the power conversion efficiency of the system is not high enough.In general,during the whole transmission process,the power passes through two conversion processes and long distance transmission as laser.So in order to improve its power conversion efficiency and make the system enter the practical application,this paper analyzes the energy conversion process at the receiving part of the whole system.The main device of the receiving part is the photovoltaic cell,and the current research on the photovoltaic cell is mainly focused on the radiation of the solar light.The research on the response characteristics and the power conversion efficiency of the photovoltaic cells under the laser irradiation is short.Therefore,in order to improve the power conversion efficiency of the photovoltaic cells irradiated by laser,so it can be applied to the laser wireless power transmission system,so that the system can enter the practical application,in this paper,the output characteristics and the power conversion efficiency of the photovoltaic cells under laser irradiation are studied through theoretical analysis and experiment.The main work is as follows:(1)Through the energy band theory and the knowledge of the p-n junction,the expression of the photo-generated current,the recombination current and the dark current of the photovoltaic cells irradiated by laser irradiation is derived,which lays the foundation for the theoretical calculation and the analysis of the experimental results;(2)A single exponential model of the photovoltaic cell under laser irradiation is established,and through the model,the voltage current characteristic function is obtained.The internal parameters of the photovoltaic cells can be extracted from the experimental data,and the internal parameters and the output characteristics of the photovoltaic cells irradiated by the laser can be quantitatively analyzed by combining the previous expression of the current of the photovoltaic cells;(3)The photoelectric model and thermal model of the photovoltaic cells irradiated by laser are established,and the output characteristics,power conversion efficiency and temperature change of different types of photovoltaic cells irradiated by different types of laser irradiation are simulated and calculated,which provides some reference for the experiment;(4)The experimental platform was built to study the effect of laser wavelength,power density,photovoltaic cell material,temperature and the angle of incident laser on the output characteristics and power conversion efficiency of the photovoltaic cells irradiated by laser.Through the analysis of the experimental results,we know that:with the increase of laser power density,the output power of photovoltaic cells increases at first and then tend to be stable,but the temperature rise caused by high power intensity laser will lead to the decrease of power conversion efficiency.So,the selection of laser power intensity and the temperature control of photovoltaic cells is the key to increase the power conversion efficiency of laser wireless power transmission system.