Research On Out Characteristics Of PV Array In UAV LPT System And GMPPT Method

Laser Power Transfer(LPT)is a technology for transmitting electrical energy using a laser as the energy carrier.This technology uses the photovoltaic effect to transfer electrical energy from the power source to the load without direct electrical contact.This technology has the advantages of good directionality,high energy density and long transmission distance,which can effectively solve the problem of short endurance of small UAVs.However,the uneven Gaussian distribution of laser energy makes the photoelectric conversion efficiency of the photovoltaic array in the UAV LPT system unsatisfactory,which seriously hinders the practical use of laser-powered UAVs.In order to solve the low photoelectric conversion efficiency of photovoltaic array in UAV LPT system,this paper investigates the output characteristics of photovoltaic array in UAV LPT system and the maximum power tracking method based on the distribution law of laser energy.The specific work of this paper is as follows.The laser wireless energy transfer technology is introduced,focusing on the optimization of the photo-electric conversion efficiency of PV arrays at the receiver side of the UAV LPT system,the current status of research on several PV array efficiency optimization methods under uneven irradiation is introduced,and the main research work of the paper is outlined.The output characteristics of PV cells are briefly described,and the output characteristics of PV arrays under laser irradiation are summarized from the simplified model of PV array electrical connection structure and laser energy distribution,and the global maximum power point(GMPP)distribution law is simulated and verified,which paves the way for the subsequent introduction of the global maximum power tracking control method at the receiver side of the UAV LPT system.Under laser irradiation conditions,two global maximum power point tracking(GMPPT)methods are proposed in this paper.Method 1 is a new GMPPT control algorithm based on the law of PV array output characteristics under laser irradiation,which contains two parts: the calculation of the theoretical value of GMPP voltage and the constant voltage method;Method 2 is an improved intelligent algorithm applied to the field of maximum power point tracking control of PV arrays,which combines the cuckoo search algorithm with the perturbation observation method,and this composite algorithm is firstly used by the cuckoo search algorithm This composite algorithm first determines the global maximum power point of the PV array by the powerful global search ability of the cuckoo search algorithm,and then switches to the perturbation observation method to precisely track and continuously and steadily output the maximum power.The UAV LPT receiver end model is built in Matlab/Simulink.The simulation results show that for laser irradiation,the proposed two GMPPT control algorithms do not fall into local optimum,both can effectively find the global maximum power point,and can effectively prevent the PV array output power from oscillating at the GMPP and improve the PV array output efficiency at the UAV LPT receiver.