Research On Energy System Structure And Optimal Scheduling Strategy Of Solar-powered UAV Near Space

Near-space solar-powered UAVs have become the focus of current UAV research due to their long flight time,wide coverage,and poor weather-resistant operations.In order to achieve long-duration flight across day and night,it is necessary to capture solar energy during the day to maintain normal flight,and at the same time store part of the energy through energy storage batteries or gravitational potential energy to achieve night cruise.The light receiving conditions of the photovoltaic array are very different with the limitation of the wing shape of the UAV,resulting in the problem that the capacity of photovoltaic and energy storage batteries cannot be fully utilized.To solve this problem,this paper conducts research from the perspective of UAV energy system structure and energy scheduling strategy to effectively improve the efficiency of energy conversion and utilization,so as to achieve full utilization of UAV airborne capacity.Firstly,this thesis establishes the photovoltaic power generation model,load model and energy storage battery charging and discharging model,analyzes the influence of factors such as different flight stages and flight attitudes,and,meanwhile,according to the characteristics of the energy system,studies the topology,working principle and energy transmission relationship of the solar UAV energy system,which lays the foundation for the subsequent study of the optimal energy dispatching strategy.Furthermore,the energy scheduling strategy suitable for photovoltaic energy storage strings composed of multiple photovoltaic energy storage modules is studied.With the goal to maximize the sum of the energy of all energy storage batteries in the string at the end of the dispatch period and to balance the energy of all energy storage batteries at the end of the dispatch period,and with the constraints of energy balance,energy storage battery charge and discharge power,energy storage battery voltage,etc.,the realization method of the corresponding scheduling strategy is studied.On the basis of strings,the thesis studies the energy dispatching strategy between strings of photovoltaic energy storage system composed of multiple strings.According to the current state of energy storage batteries and the flight path of the next day,with the goal to maximize the sum of the energy of all energy storage batteries at the end of the dispatch period,and to balance the energy of all energy storage batteries at the end of the dispatch period,and with power balance and output power constraints as constraints,a multi-objective energy scheduling optimization model is established.This model problem is solved by The Lagrangian algorithm and the energy forward algorithm.Finally,the proposed energy control strategy within a string and between strings is simulated and verified with the help of Python combined with classical flight conditions.The results verify that the energy control strategy has the effect of greatly improving the utilization rate of photovoltaic and system equipment capacity.