Power Supply Architectures for Drones - A Review

Abstract

Drones are recently receiving a growing attention in both civil and military sectors. Despite their good features such as high maneuverability, wide variety of usage, and low cost; battery-powered drones are still limited in terms of endurance. They cannot perform long flights and persistent missions. This paper proposes then a review-based discussion of the solutions addressing this issue, including swapping laser-beam inflight recharging and tethering. Hybrid power supply system is also a solution of choice. Combining battery with different sources such as fuel cell, solar cells, and supercapacitor allows the system to benefit from sources advantages and cover their limitations. In this context, this paper provides a comparative and critical study of different power supply architectures, thus facilitating the trade-off in the choice of the suitable drone power supply system. Insights and recommendations for future research are also provided.

Full text

Power Supply Architectures for Drones - A Review
Mohamed Nadir Boukoberine1, Zhibin Zhou2, Mohamed Benbouzid1,3
1University of Brest, UMR CNRS 6027 IRDL, 29238 Brest, France
2ISEN Yncr´
ea Ouest, UMR CNRS 6027 IRDL, 29200 Brest, France
3Shanghai Maritime University, 201306 Shanghai, China
Email: mohamednadir.boukoberine@univ-brest.fr, zhibin.zhou@isen-ouest.yncrea.fr,
mohamed.benbouzid@univ-brest.fr
Abstract—Drones are recently receiving a growing attention in
both civil and military sectors. Despite their good features such
as high maneuverability, wide variety of usage, and low cost;
battery-powered drones are still limited in terms of endurance.
They cannot perform long flights and persistent missions. This
paper proposes then a review-based discussion of the solutions
addressing this issue, including swapping laser-beam inflight
recharging and tethering.
Hybrid power supply system is also a solution of choice.
Combining battery with different sources such as fuel cell, solar
cells, and supercapacitor allows the system to benefit from sources
advantages and cover their limitations. In this context, this
paper provides a comparative and critical study of different
power supply architectures, thus facilitating the trade-off in the
choice of the suitable drone power supply system. Insights and
recommendations for future research are also provided.
Index Terms—Drone, power supply, swapping, laser-beam
inflight recharging, tethered drone.
I. INTRODUCTION
In recent years, drones have received great interest by
the scientific community as flying robots with high mobility
and low cost [1]. Advancements in drone technology make
them smart tools used in several applications [2]: delivery,
monitoring, border control, wireless covering, and precision
agriculture. In 2020, the drone market value is estimated to be
over US$127 billions [3].
Electric propulsion is favored for drones due to many advan-
tages such as efficiency, reliability, reduced noise and thermal
signatures and precise control [4]. The internal combustion
engine (ICE) unfortunately misses these key features, and that
prevents it from being the solution of choice despite its very
high power and energy densities. Hybridization of an ICE
with an electric motor enables the drone to benefit from both
engines advantages [5], [6]. However, decreasing pollutants
and greenhouse gases emissions in the aviation field becomes
a high-priority criteria.
Many commercial drones are powered by batteries, their
flight time reaches up to two hours. However, despite all
advancements in batteries technologies, they are still unable
to ensure long and persistent drones missions when used as
unique energy source. It is mainly due to their relatively low
energy density [7]. Multiplying batteries is unfortunately not a
practical solution, their number is limited by weight and space
constraints. Thus, drones have to carry an additional energy
source which can cover batteries limitations and extend the
endurance. In this context, a fuel cell is typically integrated
due its features such as high energy density and fast refueling.
In majority of hybrid electrical drones, the fuel cell is selected
as main power source, when the other sources are auxiliaries
supplying in special flight conditions [8]–[10]. Solar energy
is also a good option for fixed-wing drones since they are
able to carry solar cells. Therefore, the flight time can be
extremely extended to reach many days, and hydrogen can
be saved [11]–[15]. During the flight, drones are supposed to
perform different maneuvers such as take-off and climbing,
then peak power has to be supplied instantaneously. In this
context, a supercapacitor can take part in the power supply
system thanks to its very high specific power [16], [17].
Consequently, hybridization is a key option for drones to have
good performances when ensuring a large operating time. The
choice of power supply system components is then important,
both of power sources characteristics and mission type have
to be considered. In addition, implementation of an energy
management system (EMS) is necessary to keep all sources
operating with efficiency and to preserve their lifetimes.
Other approaches are available for battery-based drones
allowing them to operate continuously: swapping, laser-beam
inflight recharging, and tethering [18]–[24]. Swapping offers
the possibility to recharge the drone’s depleted batteries during
its mission using docking stations. Light energy can be trans-
ferred to drones in-flight using laser beam, batteries can then
be charged after converting light power to electricity. Tethered
drones are continuously supplied through power lines, thereby
they can have unlimited endurance.
In this paper, the attention is focused on the drone power
supply. We propose a comprehensive and critical evaluation of
drones available power supply structures and techniques pro-
viding insights about the choice of the power supply system.
At the end of the paper, some useful guiding recommendations
and prospects will be proposed.
Section 2 discusses battery-based drones supplying tech-
niques. Section 3 investigates the fuel cell as main power
source. Section 4 presents and evaluates different possible
hybrid structures used in drones power supply systems.
II. BATTERY-PO WE RE D DRON ES
Batteries constitute the pillar of battery-powerd drones.
They supply most small drones offering flexibility and sim-
plicity for the propulsion system. However, LiPo batteries

for example, can ensure drone operation for a maximum of
90 min [8]. Such limitation restricts these drones usage to
commercial purposes. Donateo et al. [4] proposed different
battery technologies evaluation considering the state of charge
(SOC) for a given mission. In [25], battery-powered drones
performances were investigated and mathematical formulation
for range and endurance estimation was proposed.
One of the most important battery-powered drones chal-
lenges is their reduced autonomy. Even with current advance-
ments in batteries technologies, flight endurance and range are
still limited by the battery specific energy. This section will
address promising techniques used to allow the battery-based
drones to recharge or replace their depleted batteries during
the flight, and then extremely increase endurance.
A. Battery-based Supplying Techniques
1) Swapping: Drones can recharge or replace their depleted
batteries during their mission using swapping technique. This
task can be autonomously conducted or human-operated. By
using drone swarm and by managing their cooperation, the
swapping-based multi-agent system can operate continuously
performing persistent missions. A typical swapping operation
need a ground recharge station for batteries charging/replacing.
It can be deployed on cell towers, rooftops, power poles, or
standalone pylons [26], [27]. This docking platform can be
fed by big batteries, power lines, or solar cells for remote
operation. Figure 1 illustrates the swapping and hotswapping
approaches and Fig. 2 shows some commercially available
ground stations (GSs).
Fig. 1. Swapping and hotswapping algorithms.
Fig. 2. Drones docking stations [28], [29].
2) Laser-beam inflight recharging: Beside the swapping
approach, wireless recharging is also proposed as solution.
Drones can be charged while flying, without the need of
landing maneuvers, thus increasing the operation safety and
efficiency [22], [30]. A prime power source should be installed
in the GS to supply the laser generator which transmits the
laser-beam to the drone’s optical receiver. When the battery
becomes discharged, an aerial power link will be established
between drone and the nearest laser source (Fig. 3). To avoid
laser-beam obstruction, GSs are deployed on rooftops of high
buildings or on mobile stations. LaserMotive developed a
working prototype of hundreds of watts [20]. In addition, more
than 12 h flight was conducted by a quadcopter in [21] proving
the feasibility of the proposed approach. This study considered
size, payload, and specific drone application. The flight control
system and the mechanical design were also presented.
Using this technique, the drone has to operate in a limited
area in order to keep the radiative link with the laser generator.
It is worth noting that the drone’s operating height is legally
limited by 120 m according to Federal Aviation Administration
(FAA) [31]. Thus, the operating range will be also limited by
this constraint. Moreover, each drone need its dedicated laser
source, therefore it is necessary to decrease drones number to
have a reasonable operational cost [22].
Fig. 3. Laser-beam powered drones [32].
3) Tethered drones: Drones can be attached to a ground
power source using connection lines to have unlimited auton-
omy. This option ensures an uninterrupted electricity supply
and prevents the drone operation to be disturbed by repetitive
recharging and extremely reducing batteries weight. It enables
also real time data transfer with safety and rapidity, especially
when using fiber technology. Fiber optic cables allow a power
transfer of many kilowatts using high-intensity light and
decreasing the detectability. Figure 4 provides an illustrative
example of tethered drone system for communication and
surveillance missions.
In [23], a tethered drone is used on the ship to detect
maritime pollution caused by the oil spilled on the sea.
Gu et al. [34] demonstrated prototypes destined to nuclear
power plants long missions attaining duration of few months.
However, a tethered drone can operate only in a limited area
since it has to be attached to the ground station. A moving
prime power source can be a solution to this issue allowing
the drone to cover a larger area.
Table I proposes a critical comparison of the battery-based
power supplying techniques.

TABLE I
COMPARISON BETWEEN DRONES BATTERY-BASED S UP PLYI NG TE CH NIQ UES .
Power supplying
technique
Advantages Limitations and drawbacks Related papers
Swapping Continuous operation, appropriate to long-range
flights, battery is the unique power source ⇒
Weight can be greatly reduced and power manage-
ment system is not needed.
The ground station (GS) is mandatory, operational
efficiency is affected by the necessity of landing
during mission, multiplying drones and batteries ⇒
High operational cost, complexity of cooperation
between drones and the GS.
[18], [19], [35]
Inflight laser
charging
Continuous operation, wireless refueling, landing
during flight is avoided, unique power source,
suitable to persistent missions.
Necessity of GS, reduced operating range and height,
concerns of laser-beam obstruction.
[20]–[22], [30]
Tethered drones Continuous operation, docking is not required, one
energy source, real-time data transfer with safety
and efficiency, persistent operation.
The GS is required, operating area is limited, risk of
drone damage when tethering is lost.
[23], [24]
Fig. 4. Tethered drone for communication and surveillance [33].
III. FUE L CEL L POWE RE D DRONES
Fuel cells when supplying drones, as illustrated by Fig.
5, can extend the endurance to hours thanks to their higher
specific energy [36]. In addition, they are refueled almost
instantly, while batteries recharging process takes a longer
time. Using Protonex 550 W PEM fuel cell, the developed
drone in [37] showed in a flight test 6 times endurance increase
than Li-Ion battery system. Indeed, fuel cells are characterized
by a lower energy density, since the fuel tank volume has to
be considered.
Fig. 5. Fuel cell based drone from Intelligent Energy [38].
A. Fuel Cells Efficiency Issue
Elements on the process of electricity production in fuel
cells can be found in [36], [39]. Fuel cells can reach a
maximum efficiency level of 60% [35]. It is still lower than
that of lithium batteries (over 90%). That is mainly due to the
auxiliary subsystems needed for fuel cell stack operation as
illustrated by Fig. 6 [36].
Fig. 6. Fuel cell system subsystems illustration [40].
B. Fuel Storage
Hydrogen has a density of only 0.089 kg/m3at standard
temperature and pressure [7], and it is not possible to store
hydrogen under extremely high pressure and low temperature
[41]. Three techniques are mainly used to overcome this
constraint: compressed hydrogen gas, liquid hydrogen, and
chemical hydrogen generation.
In [37], Swider-Lyons et al. proposed a comparative study
of hydrogen storage methods in the Ion Tiger drone when
conducting a 24 hours flight. According to several research
teams, for example, Naval Research Laboratory [42], liquid H2
can’t be the best choice since it requires specific infrastructures
[7]. In Colorado State University [10], compressed H2based
drone succeed to complete 24 hours flight-test. As regards
chemical hydrogen generation, extra equipment are required
to extract hydrogen, which make the power system heavy and
complex. In addition, hydrogen extraction process makes time,
therefore increasing drone response-time to load changes.
IV. HYBRID POWER SOURCES
1) Fuel cell and battery: Drones when powered by fuel
cells as a unique power source present some limitations.

The process of electricity generation which need air supply
using compressors, pumps, and valves increases the time-
constant (in the order of seconds) relatively to batteries. Thus,
hybridization of fuel cell and battery can lead to a power
system with effective performances combining the advantages
of both sources and balancing their drawbacks [4], [44].
Indeed, battery will supply the peak power needed in take-
off and climbing since it has higher power density and faster
response. In cruise or descend periods, fuel cell will supply
the main demand power, and it can also charge the battery to
keep the SOC in a favorable range.
In [45], authors proposed a hardware-in-the-loop (HIL)
simulations of a hybrid drone fed by a 200 W fuel cell and
a battery. This study provides an analysis of the behavior of
each source using several tests and considering endurance and
hydrogen use. In a similar study in [46], load fluctuations
were considered in HIL simulations based on real flight data.
In their experimental investigation, Gong et al. [47] assessed
the battery contribution degree under several solicitations.
However, the energy management was not considered in this
studies, power was supplied with the passive method.
2) Solar cells as extra power source: Application of solar
power in drones becomes fundamental for high altitude long
endurance (HALE) missions as illustrated by Fig. 7. Photo-
voltaic (PV) power allows drones when outfitted by battery
storage system to achieve multi-day flights carrying a variety
of sensors.
In [48], Harvey et al. investigated the effect of adding a
PV system to a power supply system based on battery and
fuel cell using HIL simulations. It was concluded that using
PVs might allow performances improvement and up to 59%
of energy saving. As shown by Fig. 7, it is clear that large
wings are needed for solar powered-drones to exploit the
maximum of available solar energy. In addition, a maximum
power point tracking (MPPT) algorithm has to be implemented
[49]. In [12], Shiau et al. have experimentally designed a solar
power management system (SPMS) for their drone powered
by solar cells and batteries. However, this study considers
only on-board electronic circuitries as load, the propulsion
power was neglected. In [49], Pen et al. have investigated
the effect of solar irradiation fluctuations on drones operation.
An interesting MPPT algorithm based on perturb and observe
(P&O) method was proposed to improve the system efficiency
and overcome this climatic constraint.
Fig. 7. Solar-powered drones [50], [51].
3) Supercapacitor as an extra power source: Supercapac-
itors are recently receiving attention in drones power supply
system since they present some advantages that can balance
batteries limitations [52]. Batteries suffer from lifetime de-
crease at high temperatures, sluggish charge/discharge, and
self-discharging.
A supercapacitor when compared to a battery, has a much
higher specific power. In addition, the supercapacitor technol-
ogy is characterized by a fast charging/discharching speed,
overcharge tolerance, and the ability to extremely reduce the
DC bus voltage fluctuations [53]. In this context, a superca-
pacitor will reinforce the hybrid power supply system offering
higher power density and allowing rapid power response (Fig.
8). In this case an energy management system (EMS) is
necessary to enable optimal operation for each power source.
In [16], Gong et al. evaluated the supercapacitor behavior
in a drone with hybrid power supply system including battery
and fuel cell. Using HIL simulations, the authors provided
a comparison with a fuel cell/battery system considering a
flight profile. This study has proved supercapacitor inducing
good performances in terms of dynamic response and load
smoothing. In another research [17], the authors developed a
real drone prototype keeping the same drone configuration. In
this study, two dynamic flight tests were conducted to show
the supercapacitor significant role in supplying peak power,
reducing power fluctuations, and DC bus voltage stabilization.
The power splitting method has unfortunately not been dis-
cussed.
A critical comparative analysis on drone hybrid power
supply configurations is proposed in Table II.
Fig. 8. A hybrid fuel cell-battery-supercapacitor drone system [54].
V. CONCLUSIONS AND FUTURE TRENDS
Drones are receiving big interest from researchers in several
domains. As the power supply system is a fundamental unit
in a drone platform, this paper has therefore dealt with
comparative and critical study on drones supplying sources and
architectures. This review-based study aims providing basis
and insights about the choice of the appropriate power supply
devices considering sources features and flight requirements.
It has also discussed supplying solution for specific mis-
sions when battery-based drones have to operate continuously,
namely swapping, laser-beam inflight recharging, and tethered
technologies.

TABLE II
COMPARISON OF HYBRID POWER SUPPLY CONFIGURATIONS.
Sources Advantages Limitations Related
papers
Thermal en-
ergy (ICE)
Very high specific
power and energy,
large autonomy and
payload range.
Thermal and acous-
tic signatures, low ef-
ficiency, GHG emis-
sion, fuel high cost.
[5], [6],
[55]
Battery High specific energy,
energy is stored (not
generated) ⇒short
response time.
Low specific power
, reduced flight time,
slow recharging, to
extend autonomy ⇒
multiply batteries ⇒
increase in both of
weight and cost.
[25],
[56]
Fuel cell High specific power,
rapid refueling with-
out ‘’memory effect”
, to extend endurance
⇒add more fuel to
the same stack ⇒
weight saved.
Energy is generated
⇒long response
time relatively,
auxiliary systems are
needed (compressors,
regulator, etc), safety
and hydrogen storage
concerns, limited
infrastructures for
hydrogen supply,
costly hydrogen
production process.
[9],
[10],
[37]
Fuel cell and
Battery
Energy and power
densities are
increased ⇒
improvements in
the endurance and the
response time, rapid
refueling and energy
storage.
Weight and volume
increase, EMS is re-
quired ⇒additional
complexity in control.
[46],
[47],
[57]–
[59]
Fuel cell,
Battery, and
solar cells
Supplementary
energy source
⇒flight time is
increased, clean,
available, and free
power ⇒low energy
cost, fuel saving.
Limited to fixed-wing
drones, large wings
constraint, necessity
of an energy storage
system, EMS with
MPPT algorithm is
needed.
[11]–
[15]
Fuel cell,
Battery, and
supercapaci-
tor
Very high power den-
sity, fast charging, re-
duced weight, and re-
duced dc bus fluctua-
tions; very long life-
time, minimum heat
loss due to the re-
duced internal resis-
tance.
EMS is needed,
supercapacitor high
cost, supercapacitor
voltage regulation is
necessary.
[16],
[17]
It can be concluded that the choice of power supply
components may not be sufficient to have optimal operation
with extended endurance. A power management system is
then required to optimally split power using optimization
strategies while respecting drone specifications. In this context,
off-line optimization methods could be proposed as a trend.
Some research works are focusing on the energy consumption
prediction using a priori flight data [60], [61].
REFERENCES
[1] M. A. Latif, “An agricultural perspective on flying sensors: State of the
art, challenges, and future directions,” IEEE Geoscience and Remote
Sensing Magazine, vol. 6, no. 4, pp. 10–22, 2018.
[2] C. Kyrkou, S. Timotheou, P. Kolios, T. Theocharides, and C. Panayiotou,
“Drones: Augmenting our quality of life,” IEEE Potentials, vol. 38, no. 1,
pp. 30–36, Jan 2019.
[3] M. Mazur, A. Wisniewski, and J. McMillan, “Clarity from above: PwC
global report on the commercial applications of drone technology,”
Warsaw: Drone Powered Solutions, PriceWater house Coopers, May
2016.
[4] T. Donateo, A. Ficarella, L. Spedicato, A. Arista, and M. Ferraro, “A
new approach to calculating endurance in electric flight and comparing
fuel cells and batteries,” Applied energy, vol. 187, pp. 807–819, 2017.
[5] E. Bongermino, F. Mastrorocco, M. Tomaselli, V. G. Monopoli, and
D. Naso, “Model and energy management system for a parallel hybrid
electric unmanned aerial vehicle,” in 2017 IEEE 26th International Sym-
posium on Industrial Electronics (ISIE). Edinburgh, United Kingdom:
IEEE, Jun. 2017, pp. 1868–1873.
[6] Y. Xie, A. Savvaris, and A. Tsourdos, “Fuzzy logic based equivalent
consumption optimization of a hybrid electric propulsion system for
unmanned aerial vehicles,” Aerospace Science and Technology, vol. 85,
pp. 13–23, 2019.
[7] A. Gong and D. Verstraete, “Fuel cell propulsion in small fixed-
wing unmanned aerial vehicles: Current status and research needs,”
International Journal of Hydrogen Energy, vol. 42, no. 33, pp. 21 311–
21 333, Aug. 2017.
[8] D. Verstraete, K. Lehmkuehler, and K. C. Wong, “Design of a Fuel
Cell Powered Blended Wing Body UAV,” in Volume 1: Advances in
Aerospace Technology. Houston, Texas, USA: ASME, Nov. 2012, p.
621.
[9] T. Kim and S. Kwon, “Design and development of a fuel cell-powered
small unmanned aircraft,” International Journal of Hydrogen Energy,
vol. 37, no. 1, pp. 615–622, Jan. 2012.
[10] G. Rhoads, T. Bradley, N. Wagner, B. Taylor, and D. Keen, “Design and
Flight Test Results for a 24 Hour Fuel Cell Unmanned Aerial Vehicle,”
in 8th Annual International Energy Conversion Engineering Conference.
Nashville, TN: American Institute of Aeronautics and Astronautics, Jul.
2010.
[11] B. Lee, P. Park, C. Kim, S. Yang, and S. Ahn, “Power managements of
a hybrid electric propulsion system for UAVs,” Journal of Mechanical
Science and Technology, vol. 26, no. 8, pp. 2291–2299, Aug. 2012.
[12] Jaw-Kuen Shiau, Der-Ming Ma, Pin-Ying Yang, Geng-Feng Wang, and
Jhij Hua Gong, “Design of a Solar Power Management System for an
Experimental UAV,” IEEE Transactions on Aerospace and Electronic
Systems, vol. 45, no. 4, pp. 1350–1360, Oct. 2009.
[13] B. Lee, S. Kwon, P. Park, and K. Kim, “Active power management
system for an unmanned aerial vehicle powered by solar cells, a fuel
cell, and batteries,” IEEE Transactions on Aerospace and Electronic
Systems, vol. 50, no. 4, pp. 3167–3177, Oct. 2014.
[14] B. G. Gang and S. Kwon, “Design of an energy management technique
for high endurance unmanned aerial vehicles powered by fuel and solar
cell systems,” International Journal of Hydrogen Energy, vol. 43, no. 20,
pp. 9787–9796, May 2018.
[15] X. Zhang, L. Liu, and Y. Dai, “Fuzzy State Machine Energy Man-
agement Strategy for Hybrid Electric UAVs with PV/Fuel Cell/Battery
Power System,” International Journal of Aerospace Engineering, vol.
2018, pp. 1–16, Jul. 2018.
[16] A. Gong, R. MacNeill, D. Verstraete, and J. L. Palmer, “Analysis of a
Fuel-Cell/Battery/Supercapacitor Hybrid Propulsion System for a UAV
using a Hardware-in-the-Loop Flight Simulator,” in 2018 AIAA/IEEE
Electric Aircraft Technologies Symposium. Cincinnati, Ohio: American
Institute of Aeronautics and Astronautics, Jul. 2018.
[17] A. Gong, J. L. Palmer, and D. Verstraete, “Flight test of a fuel-
cell/battery/supercapacitor triple hybrid uav propulsion system,” in 31st
Congress of the International Council of the Aeronautical Sciences
(ICAS 2018), p. 11.
[18] K. A. Swieringa, C. B. Hanson, J. R. Richardson, J. D. White, Z. Hasan,
E. Qian, and A. Girard, “Autonomous battery swapping system for small-
scale helicopters,” in 2010 IEEE International Conference on Robotics
and Automation. Anchorage, AK: IEEE, May 2010, pp. 3335–3340.
[19] N. Lape˜
na-Rey, J. Blanco, E. Ferreyra, J. Lemus, S. Pereira, and
E. Serrot, “A fuel cell powered unmanned aerial vehicle for low alti-
tude surveillance missions,” International Journal of Hydrogen Energy,
vol. 42, no. 10, pp. 6926–6940, Mar. 2017.
[20] J. Ouyang, Y. Che, J. Xu, and K. Wu, “Throughput Maximiza-
tion for Laser-Powered UAV Wireless Communication Systems,”
arXiv:1803.00690 [cs, math], Mar. 2018.

[21] M. C. Achtelik, J. Stumpf, D. Gurdan, and K.-M. Doth, “Design of
a flexible high performance quadcopter platform breaking the mav
endurance record with laser power beaming,” in 2011 IEEE/RSJ Inter-
national Conference on Intelligent Robots and Systems. IEEE, 2011,
pp. 5166–5172.
[22] B. Galkin and L. A. DaSilva, “UAVs as Mobile Infrastructure: Address-
ing Battery Lifetime,” arXiv:1807.00996 [cs], Jul. 2018.
[23] F. Muttin, “Umbilical deployment modeling for tethered UAV detecting
oil pollution from ship,” Applied Ocean Research, vol. 33, no. 4, pp.
332–343, 2011.
[24] A. Woodworth and J. Peverill, Tethered Aerial System for Data Gather-
ing. Google Patents, 2013.
[25] L. W. Traub, “Range and Endurance Estimates for Battery-Powered
Aircraft,” Journal of Aircraft, vol. 48, no. 2, pp. 703–707, Mar. 2011.
[26] E. W. Saad, J. L. Vian, M. A. Vavrina, J. A. Nisbett, and D. C. Wunsch,
Vehicle Base Station. Google Patents, 2014.
[27] N. K. Gentry, R. Hsieh, and L. K. Nguyen, Multi-Use UAV Docking
Station Systems and Methods. Google Patents, 2016.
[28] P. C. Miller, “Skysense releases new drone charging stations,”
http://uasmagazine.com/articles/1787/skysense-releases-new-drone-
charging-stations, Dec 6 2017, ( Accessed on 10-05-2019).
[29] “Yacob - drone docking station,” https://www.thomasmore.be/en/node/19-
82, ( Accessed on 10-05-2019).
[30] M. Lu, M. Bagheri, A. P. James, and T. Phung, “Wireless charging
techniques for uavs: A review, reconceptualization, and extension,” IEEE
Access, vol. 6, pp. 29 865–29 884, 2018.
[31] J. Flynt, “How high can you fly a drone?” https://3dinsider.com/drone-
altitude, Nov 29 2017, ( Accessed on 17-05-2019).
[32] P. E. Ross, “UAV flies on laser light,” https://spectrum.ieee.org/tech-
talk/aerospace/military/uav-flies-on-laser-light, Aug 8 2012, ( Accessed
on 10-05-2019).
[33] “AirMast – Sky Mast for Communication and Surveillance,”
https://www.uasvision.com/2016/12/12/airmast-sky-mast-for-
communication-and-surveillance/, Dec 12 2016, ( Accessed on
10-05-2019).
[34] B. W. Gu, S. Y. Choi, Y. S. Choi, G. Cai, L. Seneviratne, and C. T.
Rim, “Novel roaming and stationary tethered aerial robots for continuous
mobile missions in nuclear power plants,” Nuclear Engineering and
Technology, vol. 48, no. 4, pp. 982–996, 2016.
[35] Y. Wang, K. S. Chen, J. Mishler, S. C. Cho, and X. C. Adroher,
“A review of polymer electrolyte membrane fuel cells: Technology,
applications, and needs on fundamental research,” Applied Energy,
vol. 88, no. 4, pp. 981–1007, Apr. 2011.
[36] Z. Pan, L. An, and C. Wen, “Recent advances in fuel cells based
propulsion systems for unmanned aerial vehicles,” Applied Energy, vol.
240, pp. 473–485, 2019.
[37] K. Swider-Lyons, R. Stroman, G. Page, M. Schuette, J. Mackrell, and
J. Rodgers, “Hydrogen Fule Cell Propulsion for Long Endurance Small
UVAs,” in AIAA Centennial of Naval Aviation Forum” 100 Years of
Achievement and Progress”, 2011, p. 6975.
[38] B. Lillian, “Intelligent energy develops hydrogen fuel cell range
extender for drones,” https://unmanned-aerial.com/intelligent-energy-
develops-hydrogen-fuel-cell-range-extender-for-drones, Dec 16 2015, (
Accessed on 10-05-2019).
[39] J. Larminie, A. Dicks, and M. S. McDonald, Fuel Cell Systems Ex-
plained. J. Wiley Chichester, UK, 2003, vol. 2.
[40] W. R. W. Daud, R. Rosli, E. Majlan, S. Hamid, R. Mohamed, and
T. Husaini, “Pem fuel cell system control: A review,” Renewable Energy,
vol. 113, pp. 620–638, 2017.
[41] K. Kendall and B. G. Pollet, “Hydrogen and Fuel Cells in Transport,”
Comprehensive Renewable Energy, vol. 4, p. 301, 2012.
[42] R. O. Stroman, M. W. Schuette, K. Swider-Lyons, J. A. Rodgers, and
D. J. Edwards, “Liquid hydrogen fuel system design and demonstration
in a small long endurance air vehicle,” International Journal of Hydrogen
Energy, vol. 39, no. 21, pp. 11279–11 290, 2014.
[43] J. J. Cooley, P. Lindahl, C. L. Zimmerman, M. Cornachione, G. Jordan,
S. R. Shaw, and S. B. Leeb, “Multiconverter system design for fuel cell
buffering and diagnostics under uav load profiles,” IEEE Transactions
on Power Electronics, vol. 29, no. 6, pp. 3232–3244, 2014.
[44] N. Belmonte, S. Staulo, S. Fiorot, C. Luetto, P. Rizzi, and M. Baricco,
“Fuel cell powered octocopter for inspection of mobile cranes: Design,
cost analysis and environmental impacts,” Applied energy, vol. 215, pp.
556–565, 2018.
[45] D. Verstraete, J. R. Harvey, and J. L. Palmer, “Hardware-in-the-loop
simulation of fuel-cell-based hybrid-electrical UAV propulsion,” in Pro-
ceedings of the 28th Congress of the International Council of the
Aeronautical Sciences, September, 2012, pp. 23–28.
[46] A. Gong, J. L. Palmer, G. Brian, J. R. Harvey, and D. Verstraete,
“Hardware-in-the-loop simulation of a fuel-cell-based UAV propulsion
system using real-world flight data,” in Proceedings of the Fourth
Australasian Unmanned Systems Conference, Australian Association for
Unmanned Systems, 2014, p. 7.
[47] A. Gong and D. Verstraete, “Role of battery in a hybrid electrical fuel
cell uav propulsion system,” in 52nd AIAA Aerospace Sciences Meeting,
2014.
[48] J. R. Harvey, R. A. Jarvis, D. Verstraete, R. L. Bagg, D. Honnery, and
J. L. Palmer, “Development of a hybrid-electric power-system model
for a small surveillance aircraft,” in 28th International Congress of the
Aeronautical Sciences, 2012.
[49] L. Peng, S. Zheng, X. Chai, and L. Li, “A novel tangent error maximum
power point tracking algorithm for photovoltaic system under fast multi-
changing solar irradiances,” Applied energy, vol. 210, pp. 303–316,
2018.
[50] Dricus, “Top 8 solar powered drone (UAV) developing companies,”
https://sinovoltaics.com/technology/top8-leading-companies-
developing-solar-powered-drone-uav-technology, Jul 9 2015, ( Accessed
on 10-05-2019).
[51] “The future of solar-powered drones,”
https://www.droneblog.com/2018/11/20/the-future-of-solar-powered-
drones, Nov 20 2018, ( Accessed on 10-05-2019).
[52] M. Aneke and M. Wang, “Energy storage technologies and real life
applications–a state of the art review,” Applied Energy, vol. 179, pp.
350–377, 2016.
[53] J. Ruan, P. D. Walker, N. Zhang, and J. Wu, “An investigation of hybrid
energy storage system in multi-speed electric vehicle,” Energy, vol. 140,
pp. 291–306, 2017.
[54] S. Mukhopadhyay, S. Fernandes, M. Shihab, and D. Waleed, “Using
small capacity fuel cells onboard drones for battery cooling: An exper-
imental study,” Applied Sciences, vol. 8, no. 6, p. 942, 2018.
[55] E. Bongermino, M. Tomaselli, V. G. Monopoli, G. Rizzello, F. Cuper-
tino, and D. Naso, “Hybrid Aeronautical Propulsion: Control and Energy
Management,” IFAC-PapersOnLine, vol. 50, no. 2, pp. 169–174, Dec.
2017.
[56] R. Mike, “Whitepaper: Fuel Cell-Based Energy Systems for Commercial
UAVs,” Unmanned Systems Technology, Jul. 2018.
[57] X. Zhang, L. Liu, Y. Dai, and T. Lu, “Experimental investigation on
the online fuzzy energy management of hybrid fuel cell/battery power
system for UAVs,” International Journal of Hydrogen Energy, vol. 43,
no. 21, pp. 10 094–10 103, May 2018.
[58] L. Karunarathne, J. T. Economou, and K. Knowles, “Fuzzy Logic
control strategy for Fuel Cell/Battery aerospace propulsion system,” in
2008 IEEE Vehicle Power and Propulsion Conference. Harbin, Hei
Longjiang, China: IEEE, Sep. 2008, pp. 1–5.
[59] Z. Yang, T. Lei, Z. Lin, H. Fu, and X. Zhang, “The Testing Platform
of Hybrid Electric Power System for a Fuel Cell Unmanned Aerial
Vehicle,” in 2018 IEEE International Conference on Electrical Systems
for Aircraft, Railway, Ship Propulsion and Road Vehicles & International
Transportation Electrification Conference (ESARS-ITEC). Nottingham:
IEEE, Nov. 2018, pp. 1–8.
[60] H. V. Abeywickrama, B. A. Jayawickrama, Y. He, and E. Dutkiewicz,
“Comprehensive energy consumption model for unmanned aerial vehi-
cles, based on empirical studies of battery performance,” IEEE Access,
vol. 6, pp. 58 383–58 394, 2018.
[61] A. S. Prasetia, R.-J. Wai, Y.-L. Wen, and Y.-K. Wang, “Mission-based
energy consumption prediction of multirotor uav,” IEEE Access, vol. 7,
pp. 33 055–33 063, 2019.