PV System Design and Flight Efficiency Considerations for Fixed-Wing Radio-Controlled Aircraft—A Case Study

Abstract

The list of photovoltaic (PV) applications grows longer every day with high consideration for system efficiency. For instance, in spite of many recent PV aircraft designs, aircraft propulsion was mainly reserved for nonelectric motors. Lately, the Solar Impulse flight across the world shows the possibilities of larger PV powered electric aircraft. In order to obtain this goal efficiency of flight, PV conversion, power converters and electric drives have to be maximized. These demands led to a 63.4 m wingspan. The purpose of this paper is to present that PV power could be used for improving the performance of fixed-wing radio-controlled aircrafts with smaller wingspans (1 m). In order to improve the performance of battery powered electric unmanned aerial vehicles (UAV), a model without PV cells (commercial Li-ion battery powered UAV) was compared with UAV powered both from battery and PV modules. This work shows details about Boost DC/DC converter and PV system design for small size fixed-wing electric UAVs, investigating the possibility of the application of PV powered drones, as well. Theoretical findings involving efficiency improvements have been confirmed by measurements combining the improvements in electrical engineering, microcontroller application and aerodynamics.Energies 2018, 11, 2648 2 of 12 from an energetic point of view. For example, conventional airplanes consume large quantities of kerosene, so there are efforts to reduce that consumption in order to achieve both economic and ecological impact on modern life [11].In this paper, an improvement of radio-controlled aircraft with a PV system addition has been investigated. The Solar Impulse project has shown that PV powered airplanes can fly across great distances [5,12,13], but what about smaller planes at lower altitudes? Is it possible for them to stay in the air for a few days? In this paper, a radio-controlled unmanned aerial vehicle (UAV) with a fixed-wingspan of less than 1 m has been tested without a PV supply. Different flight data like flight speed, range and time have been measured. Mass increase of the UAV (PV modules are no exception) results in shorter flight time. On the other hand, additional PV energy could compensate for battery discharging and increase flight time. Compared to the same problem in road vehicles, airplanes and their models are more exposed to periodic wind blows, sun radiation fluctuation and nonlinear phenomena of thermal air flows. In the literature, different approaches could be found, including the axiomatic approach [14] or more conventional approaches [15][16][17][18][19][20]. After the calculations, an additional PV source has been added to the wings including a Boost DC/DC power converter with a maximum power tracking (MPPT) function [21,22]. Special care has been added to the DC/DC power converter in order to reduce its mass, so different approaches were tested and compared. Finally, a new fixed-wing radio-controlled UAV based on [23] was designed at this time with a flying stability problem. After solving t...

Energy Management of Solar-Powered Aircraft-Based High Altitude Platform for Wireless Communications

“…While numerous studies [9][10][11][12] discuss the design and performance of solar-powered aircraft, most focus on aeronautics. A few studies [13,14] consider solar cell energy harvesting in relation to solar-powered aircraft. However, while the emphasis of [13] is on aerodynamic structural design of solar powered HAP, the authors in [14] focus on the solar energy performance of smaller aircraft of 1 m wingspan.…”

“…A few studies [13,14] consider solar cell energy harvesting in relation to solar-powered aircraft. However, while the emphasis of [13] is on aerodynamic structural design of solar powered HAP, the authors in [14] focus on the solar energy performance of smaller aircraft of 1 m wingspan. Understanding energy harvesting requires a realistic energy model for HAPs.…”

“…The current state-of-the-art in solar cell is an ultra-thin GaAs solar cell with power conversion efficiency of 37.5% and specific power of 3 kW/kg [40]. Using the proposed energy collection model given in (14) and assuming a solar cell efficiency of 37.5%, we evaluate the total energy collected per wingspan on the 21st of December at Enugu and York in Table 3 following the result plotted in Figure 8. The total solar irradiance per unit area for York and Enugu used in the evaluations are 1.5 kWh/m 2 and 10 kWh/m 2 respectively based on Figure 8.…”

“…Typically, this conforms to the expectation of lesser solar irradiance towards the North Pole. Combining (14), (20) and (30), an inequality that must be satisfied in order to overcome the energy constraint and close the energy budget for a platform with a particular wingspan is expressed as follows:…”

Aerial Surveillance with Low-Altitude Long-Endurance Tethered Multirotor UAVs Using Photovoltaic Power Management System

“…In addition, load C-rates used in two test cases were less than 1 C, and this is not adequate for the multirotor UAV application which uses dozens of C-rates. Kranjec and et al developed a PMS to control power flows between PV modules, a battery pack, and a brushless direct current (DC) machine, but they only passively controlled by managing the duty cycle of a transistor attached near the PV modules rather than controlling all power sources [10].…”