Study On The Power Regulation Strategy For The Energy Subsystem Of The Stratospheric Aircraft

The altitude of the stratospheric airship can reach tens of thousands of meters,covering hundreds of kilometers,and can perform many tasks.It has the irreplaceable superiority of conventional aircraft.The energy system is an important part of the stratospheric airship.Its function is to convert the solar radiation energy into electric energy and provide long-term power for the aircraft.The stratospheric airship energy system designed in this paper consists of solar energy and lithium-ion batteries,enabling the airship to remain in space for several years.First,this paper analyzes the design index and the realization of the energy subsystem,and determines the function that the system needs to realize,and discusses the design of each part of the energy subsystem,including the photovoltaic module,the DC-DC module,the battery and so on.Secondly,on the basis of understanding the features of each functional unit in the energy subsystem,the principle of energy management is introduced,and a centralized energy management strategy based on the power balance equation is proposed.Finally,on the basis of the design of the traditional energy management system,this paper optimizes the design of the MPPT controller to track the maximum power point using an improved variable step size disturbance observation method,and puts forward a variable power tracking control strategy based on the perturbation observation method.When the battery is full of electricity and the power of the photovoltaic cell is too high under the maximum power point tracking mode,the energy subsystem will generate energy accumulation.Through the variable power tracking method,the photovoltaic cells find the power points matched with the load and realize the dynamic balance adjustment of the load power.The variable power tracking method is to change the maximum power point tracking process by adding an additional amount related to the DC bus voltage in the maximum power point tracking process,and then change the end voltage of the photovoltaic cell and reduce the output power of the photovoltaic cell.This method can quickly and effectively solve the power balance problem of energy system without changing the original configuration of the energy system and adding additional equipment.The feasibility of the proposed strategy is verified by the simulation experiment of the strategy described in this paper by MATLAB.