Application Of Near Space Aerostatics Power Source System Efficiency Optimization Control

Near Space’s strategic value has drawn the world’s attention during recent years. Asthe exploration and development platform for Near Space resources, Near Space Aerostattechnique has emerged as the times require. And its potential military and civilian use isalso becoming a research focus gradually. Now abundant money has been invested into theresearch of the Near Space Aerostat technique in many countries. As to the aerostat, powersupply system is just like a “heart” of it. Each subsystem can operate well in the conditionthat the power system works stably. Since the power supply ensures the aerostat a stableand efficient operation, it is significant to research the power system. Its research hasimportant theoretical and application values for optimal utilization of solar power andstorage battery systems which are nonlinear, difficult to model and strong coupled.Referring to some literatures, four main parts: energy acquisition, energy absorption,energy transformation and energy storage of aerostat power management system, aremainly discussed in this article.And also a set of optimal control algorithm for near spaceaerostats power source system is put forward and a practical hardware platform isdesigned. Software simulations of control algorithm and designed circuit are implementedusing Matlab/Simulink and PSpice respectively. The validity of the proposed scheme foreach subsystem and the effevtiveness of the whole platform are proved through simulationexprements. This article discusses a power management system for aerostats in thefollowing points.Firstly, according to operational characteristics of aerostat, the impacts ofenvironmental conditions and different load on the power system during flight areanalyzed. And detailed analysis and design about the key techniques of the aerostat’spower systems are made with considering the relationship of light conditions and the peakpower. Then based on the principle of conservation of energy, a design scheme for thepower matching system of aerostat is put forward. Additionally through analyzing thelow-altitude simulation test data, feasibility of the proposed scheme is demonstrated, andrelated key issues are analyzed in detail. Secondly, to solve the problem that the current MPPT approach can’t take dynamicperformance and steady-state performance into account together, a improved MPPTapproach based on conjugate gradient method is proposed, which is applied to control theBoost DC/DC transducer to adjust the output power of photovoltaic cells effectively. Agreat deal of simulations are conducted which shows that the proposed system can trackthe solar energy maximum power point and has good steady-state performance.Additionally, to overcome the defects of the existing storage battery system, whichare slow charging speed, trend to overcharge and low charging efficiency, a modifiedthree-stage fast charge method based on the fuzzy adaptive PID is presented. By a largequantity of simulations, it has been proved that the proposed method can effectivelyincrease the efficiency, prolong the battery service life, thus prolonging whole aerostatsystem service life and increasing the total energy efficient.Finally, a whole near space aerostat power management system platform is designed,which consists of the following three parts: the whole power management system’s energyacquisition and absorption part consisted of solar-tracking Fresnel lens line-focusedconcentrator; the whole power management system’s energy transformation part consistedof solar energy maximum power point tracking system based on conjugate gradientmethod; the whole power management system’s energy storage part consisted of modifiedthree-stage fast charge method based on the fuzzy adaptive PID. The stability andreliability of the proposed system is verified completely through software simulations andhardware platform tests.