Analysis of the Hybrid Power System for High-Altitude Unmanned Aircraft

Shan

Mathematical Problems in Engineering

et al. 2020

Making use of solar energy to fly is an up-and-coming technology in the human aviation field since solar energy is renewable and inexhaustible, and more and more attention and efforts have been directed to the development of high-altitude solar aircraft (HSA). Due to the technical constraints of the rechargeable battery, the HSA must carry sufficient batteries to meet the flight power consumption at night, which seriously limits the flight endurance of HSA. To solve this contradiction, the paper has proposed a new energy management strategy (EMS) of multiple flight phases for HSA based on the gravitational energy storage and mission altitude, which aims to achieve the goal of long-endurance flight for HSA. The integrated model of this new EMS includes the aerodynamic model, the kinematic model, the solar irradiation model, the battery model, and the energy management model. Compared with the current EMS of level flight, the flight path of HSA in the new EMS has been divided into five phases: the lower altitude level flight at night, the maximum power ascending for mission altitude, the level flight at mission altitude, the maximum power ascending for higher altitude, and the longest gliding endurance. At last, the calculation of the new EMS for Zephyr 7 is studied by MATLAB/Simulink, and the calculation results indicate that about 22.9% of energy surplus can be stored in battery with the new EMS for Zephyr 7 compared with the current EMS, which is equal to reducing the rechargeable battery weight from 16.0 kg to 12.3 kg. Besides, the results of simulation in the four seasons also show that the new EMS is a very promising way to achieve the long-endurance goal for high-altitude HSA when the flight conditions satisfy some constraints like the deficiency of solar flux and the limit of battery mass.

Section: Problem Implementation Frame and Solving Processmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Energy Management Strategy for High-Altitude Solar Aircraft Based on Multiple Flight Phases

Shan

Mathematical Problems in Engineering

et al. 2020

J.Aerosp. Technol. Manag.

“…Nowadays, photovoltaic cells have been the largest source of alternative energy studied and applied. Therefore, there are references about 40 manned and unmanned experimental aircraft that take advantage of its features, performing missions in civil and military scenarios as: the Sky Sailor, the Helios and the Solar Impulse, that have successfully used photovoltaic solar energy as a source of power for their operation (Nickol et al 2007;Sun et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Design and Manufacture of a Solar-Powered Unmanned Aerial Vehicle for Civilian Surveillance Missions

Betancourth

Villamarín

Ríos

et al. 2016

In order to promote the development of renewable energy and take advantage of the new technologies for the benefit of sustainability, both the design and the manufacture methodologies of an experimental solarpowered unmanned aerial vehicle for civilian surveillance applications are presented. Throughout the document, it is provided the historical process around the development of the aircraft. Therefore, in the first part, it is shown the aerodynamic design, which includes the 2-D and 3-D analyses of the wing platform using numerical and experimental methods, the analytical design of the empennage configuration, and the main characteristics of the performance analysis. In addition, major systems and components that characterize the aircraft are described, such as the photovoltaic solar cells configuration as well as the electronics and control system into the unmanned aerial vehicle. Lastly, the modeling for the weights distribution of the components was carried out in a preliminary test using CAD tools. Thus, it was obtained a suitable process for the manufacture of the unmanned aerial vehicle, considering that the purpose of the aircraft is to be as light and aerodynamic as possible to accomplish the mission for which it was created.

“…Conventional solar modules exhibit 0.4% decrease in output power per 1 °C rise in temperature beyond the threshold operating temperature 16 . The temperature on the back-side of module in UAV’s can rise up to 70 °C 17 . Similarly, there is increasing emphasis on development of the heat management system for data centers.…”

mentioning

confidence: 99%

Thermo-Magneto-Electric Generator Arrays for Active Heat Recovery System

Chun

Song

Kang

et al. 2017

Sci Rep

Continued emphasis on development of thermal cooling systems is being placed that can cycle low grade heat. Examples include solar powered unmanned aerial vehicles (UAVs) and data storage servers. The power efficiency of solar module degrades at elevated temperature, thereby, necessitating the need for heat extraction system. Similarly, data centres in wireless computing system are facing increasing efficiency challenges due to high power consumption associated with managing the waste heat. We provide breakthrough in addressing these problems by developing thermo-magneto-electric generator (TMEG) arrays, composed of soft magnet and piezoelectric polyvinylidene difluoride (PVDF) cantilever. TMEG can serve dual role of extracting the waste heat and converting it into useable electricity. Near room temperature second-order magnetic phase transition in soft magnetic material, gadolinium, was employed to obtain mechanical vibrations on the PVDF cantilever under small thermal gradient. TMEGs were shown to achieve high vibration frequency at small temperature gradients, thereby, demonstrating effective heat transfer.