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In view of solar arrays applied in large-scale stratospheric airship, modular thinking was proposed by reasonable decomposition of solar array to design composite maximum power point tracking (MPPT) controller where the input and output are both in parallel, which ensures maximized solar energy output on a limited area. And each solar array sub-model was equipped with independent MPPT controller to control power tracking separately. Then, the solar array composed of three sub-models was used for simulation and its result indicates that MPPT controller of each sub-model can track the power quickly, and the output power can reach 93% of maximum input power when the efficiency loss of converter in reality is not considered . So, the model constructed in this paper can be used to optimize the design and analyze output characteristics quantitatively for the large-scale stratospheric airship's solar array.

Using only photovoltaic battery on solar-powered aircraft will waste energy because of its low conversion efficiency. For reusing the energy that converted into heat by photovoltaic cells, a hybrid power system is presented in this paper for solar-powered aircraft. Its a new electricity-generating method that spreading photovoltaic cells on the wing surface and arranging photothermal cells in the wing box section. Due to temperature of the back of photovoltaic battery is high, it can be used as high temperature heat source. And the lower wing surface can be a low temperature cooling source. A lightweight solar-powered UAV was used to analyze the relevant performances of pure photovoltaic powered aircraft and hybrid powered aircraft. The result shows that using hybrid system can reduce the area of wing by 4.6%, and solar-powered aircraft with a 6m or below-6m wingspan can raise the utilization rate of solar energy per unit area by adopting hybrid power system.

As one of the key technic of achieving high-altitude and long-time flight, the stratospheric airship energy system in stratosphere is always the important point but also very difficult. In this paper, the stratospheric airship geometry analysis as a starting point, through a series analysis as follow: the stratospheric airship surface mesh model, the sun vector, the relationship between the sun vector and the body coordinate system, and the solar radiation model, we have accomplished the characteristics analysis of the radiation receiving on stratospheric airship. The analysis result show that: Although different flight direction corresponding to different distribution of light intensity, the light changes from sunrise to sunset is symmetrical when the stratospheric airship on the condition of level flight. Airship for east heading of region resides, the maximum energy can be obtained when the solar array laying in the installation of 0 β π / 4. With the changing of heading angle and pitch angle, the radiation receiving of the solar array can also transform, but the influence of pitch angle greater than heading angle.

Cell temperature can reach as high as 70 oC while working, using only photovoltaic battery in the solar plane will result in a waste of energy. Combined with the wing configuration, a hybrid energy design method with higher efficiency is presented: photovoltaic cells will be distributed on the wing surface and photothermal cells will be arranged in the wing box section. The back of photovoltaic battery can be used as high temperature heat source and the lower wing surface can be a low temperature cooling source. Through the research of photovoltaic cells maximum power output, the envelope method ensures the output power, improves the power tracking reliability, and reduces difficulty in the design. The structure design of thermoelectric battery P-N junction is optimized by using the maximum power and maximum power to-mass ratio as objective function. The optimal solution of P-N junction structure of a certain type thermoelectric battery is given for acquiring maximum power-to-mass ratio.

The simulation model of PV module, which is based on Simulink software, the mathematical model and the equivalent circuit of PV module, is established in this paper. This PV module model can be used to show the output characteristics of PV module under different irradiations and temperatures. Moreover, this model can be extended to various parameters of PV modules and used to study parallel and serial characteristics of PV module. The output characteristics of PV module, which is affected greatly by light irradiation and ambient temperature, has obvious non-linear features. Therefore, a maximum power point tracker (MPPT) is needed. Compared with perturbation and observation (P&Q) control method and other MPPT control methods, incremental conductance (IncCond) method may be unease to be adopted because it needs a high-performance controller which is costliness. However, as IncCond method is suitable for the irradiation situation of both rapid and slow changes, it has important research meanings. Meanwhile, aiming at the disadvantage of a fixed tracking step size, a improved control method is put forward and simulated in this paper. Finally the simuliation results verify the accuracy and superiority of the improved IncCond method.