SOLAR POWERED UNMANNED AERIAL

VEHICLE
Hima M1, K.C Sindhu Thampatty 2
1,2
Department of Electrical and Electronics Engineering, Amrita School of Engineering, Coimbatore,
Amrita Vishwa Vidyapeetham, India
Email:cb.en.p2ret20008@cb.students.amrita.edu, t sindhu@cb.amrita.edu

Abstract—Drones, or unmanned aerial vehicles, are gaining One of the cost-effective solutions for extending the
popularity around the world due to their ease of use and vast range flight endurance is incorporating the renewable sources of
of applications. The biggest issue with UAVs is their battery energy. The growth of Renewable energy over the past few
endurance. Drones on the market nowadays use serially connected decades is commendable and it is still in its growing stage.
lipo batteries to generate power. In continuous motion, these There has been a major switching from conventional source
serially connected lipo batteries can offer continual power for up
of energyto non-conventional source of energy. Earth receives
to one hour. The lack of power for continuous use limits the use of
drones in several fields. The paper aims to develop a system model almost 174 petawatts of solar energy per day which is 10000
that can use the abundant form of sunlight to poweran unmanned times more than the total energy required by the world in
aerial vehicle. This paper describes a theoretical model that total. Ifthe total solar energy reaching the earth per day can be
switches between battery and solar panel based on the available tapped, it is sufficient enough to meet the total energy
power. The former part of the paper describes a basic model for requirement of whole world for one year.
the switching circuitry and the latter part describesa switching Solar energy can be coupled with the battery to improve
Circuit that switches between the solar panel and battery based on the flight timing. The concept of UAV in association with solar
the power requirement during various levels of flight. The power has been on experimentation ground since 1980. In 1970
system is developed using MATLAB/SIMULINK model.
NASA learned on the scope of developing a nuclear- powered
Index Terms—Unmanned Aerial vehicle (UAV), Quadcopter,
Solar power, DARPA, MPPT, drone. UAV which is followed by Defense Advanced Re- search
Projects Agency (DARPA). DARPA developed battery that can
I. INTRODUCTION produce enormous amount of electrical energy for meeting the
requirement of electrically propelled UAV. Later Air force
Unmanned aerial vehicle became popular during the
invested on developing a solar powered UAV. The lack of
period of World War 1. They found a major application in
availability of sufficient technology and the exorbitant price of
military purpose during the early period. With the advent of
solar made it difficult to be implemented. Over the years with
better technology and reduction in the fuel cost the application
the growth in science the first solar powered UAV was made in
of Unmanned Aerial Vehicle (UAV) has extended to non-
to reality in the year of 1980 by US named Solar challenger.
militaryapplications also. Now there are around 11000 of
Solar powered UAV has many advantages com- pared to
UAV thatis used for various applications. These applications
traditional UAV such as capability, longer endurance,stability,
include surveillance, agriculture monitoring, e- commerce,
perks etc.
deliveryservices etc. Major MNC’s like amazon, ola are
Morton [1] proposes a study that discusses the many
investing a greater capital in drone with the vision to expand
compo- nets of an autonomous aerial vehicle and how it
their service through air. A significant progress has also been
must beable to fly for longer periods of time. The report
made in the field of autonomizing aerial vehicle, such a system
assessesthe many elements that influence the flying time. The
will navigate itself without requiring a remote control. Though
many ways for improving these factors are investigated.
there have been multiple breakthroughs in the field of un-
Payloadis the most important factor in quadcopter efficiency
manned aerial vehicle, the drawbacks in terms of battery life
out of all the parameters. Other important elements that
and efficiency limit the use of quadcopter in application that
influence system performance are battery size, construction,
require an extended time of flight. To ensure a successful
and weight.Using the proposed mathematical design approach,
completion of task either a complementary UAV must be
the power consumption-to-take-off time can be reduced.
assigned or the vehicle must be landed for refueling. Both of
Parvathy Rajendran provided three new design considerations
the solutions require a lot of time and include technical
for sizing consideration to optimize UAV designs [2]. A design
difficulty.
on how to build and design a UAV using ANSYS was
discussed by karthika et.al [3].
979-8-3503-0500-5/23/$31.00 ©2023 IEEE
S. Karthik [4] discusses the design and construction of an the study system and Section III discusses on the system model
unmanned solar aircraft prototype. This project is about followed by Result and Discussion in section IV. Section V give
unmanned aerial vehicles (UAVs) that fly for more than 24 the conclusion o f t h e p r o p o s e d wo r k .
hours on solar energy alone. This review paper gives an
II. STUDY SYSTEM
overview of solar aircraft’s history, applications, and uses, with
a focus on the design and fabrication of an unmanned prototype This section discusses on the basic block diagram of proposed
solar aircraft. Kitt C. Reinhardt [5] discusses a study that was solar powered unmanned aerial vehicle. Various parts of
carried out to see how the size of solar powered aerialvehicle quadcopter are also explained in this section. The primary
are affected by the size of components while using the system concept is to use solar cells to convert infinite sun energy into
in high altitude application. The findings says that the size of power. When sunlight strikes a solar cell, it produces charge
the battery has the biggest impact and the PV efficiencyhas the carriers such as electrons and holes, and when a circuit is
least impact. An efficient propulsion system reducesthe established, the freely moving electrons move through a
dependence of power from the battery. This was explained in specified load to combine with holes, generating current. Cells
[6]. are connected in series on the quadcopter’s top to create the
Xinhua L [7] explains the overall design technique for voltage required to safely power up the motor. The power
a quadcopter drone that is powered by solar irradiation, with required by the motor varies depending on the time of flight.
a focus on propulsion system planning. The impact of blade The motor’s power requirements are analyzed, and depending
area and aspect ratio on optimal design outcomes is explored on power availability, power is either fully supplied to the
and differentiated with the conventional design method. motor or divided between the motor and the battery which are
B Karthik Reddy. S [8] To confirm the design’s discussed in the latter part of the paper. In the context,the
practicality, conducted a rigorous Energy and Power study. R. flight was deemed to be a quadcopter, which indicatesit
Vijayanandh [9] Using CATIA V5 and theoretical design improves energy efficiency in the battery while gliding. This
parameters, made a novel work on the total 3D solar UAV. enables the plane to be flown entirely on solar energy while
MATLAB was used to finish the detection of intruders in also saving the power in the battery to extend the flight
boundaries via image processing. W W Zhang [10] duration.
demonstrates that solar aircraft’s dynamic arrangement and
Fig. 1. Basic Block diagram for solar powered Unmanned aerial vehicle
construction design have a massive effect on aircraft
performance and quality. Multiple studies to measure solar
power system and airframe performance, were recommended
by N. Papanikolopoulos [11]. The plane is built for a payload
of 2 kg and is examined in many ways. Furthermore, Sri K.R.B,
Aneesh P [12] presented adesign that is optimized from the air
foil to the entire structure for improved performance. A study
on the use of a multilevel inverter and a quadratic buck-boost
converter (QBBC) to harvest electrical energy from solar cells
and link it to the single phase grid (MLI) is
discussed[13].Simulink software is used to build and simulate
a controller unit that calculates system operation and output
power under changing irradiance andPSC.[14].With the use of Figure 1 represent the overall block diagram of the
MPPT, IOFL, PLL, and power anglecontrol, a straightforward, proposed system. The system consists of a solar panel of
practical technique of solar power control to the grid was 50W. A lipo battery is used as complementary power source.
explored in[15].[16] gives insight on various wireless charging The controller gathers the input from the solar panel, main
methodologies for unmanned aerial vehicle. battery and motor. Multiple switches are used in the proposed
There are multiple researches in the field of solar system. A Switch is connected between solar panel and battery.
powered unmanned aerial vehicle. The foremost issue is the Whenever the voltage of the solar panel is high enough to
battery endurance capability of the unmanned aerial vehicle supply to the motor, the corresponding switch will switch to
which restricts the usage of drone in multiple applications for a solar panel and during the non-sunshine hours the switch will
longerperiod. toggle to battery. In the next stage, the microcontroller gathers
This paper aim on developing a solar powered drone the data from battery and motor and based on the power
that can make use of solar energy and battery in requirement of the motor the power is shared between the
complementary for a longer flight duration The proposed battery and motor. At this instance both switches to motor and
system includes the simulation of solar powered UAV which main battery will be turned ON. During the period of take off
makes use ofboth battery and solar panel to meet the power the power requirement is less, so the power from the solar
requirement.In the initial stage of the model, a Model that panel is split between battery and motor. When the motor is
can switchthe power between solar panel and battery based hovering the power requirement is highso the full power from
on the voltage is designed and later the same system is solar panel is supplied to motor. At this instance only switch
redesigned to switch the power based on the power requirement to motor is switched ON. When the output of solar panel is
at various stages of flight. low the battery will continue to supply power through the
The following sections summarize the work on corresponding switch.
development of a model for solar powered. Section II describes
 B. Selection of Components selection of motor is dependent on the relationship between
thrust and weight of the system. The total weight of the system
1) Selection of Motor: The selection of Motor rating is including solar panel and quadcopter structure is 2kg
the foremost criteria for a stable operation of a drone. The
A. Main Components of Solar Powered Unmanned Aerial
Vehicle T
Ratio = (1)
1) Quadcopter: A quadcopter, sometimes known as a W
quadrotor, is a helicopter with four rotors. Drones’ tiny size and
low inertia enable for the adoption of a very simple flight (2)
control system, considerably increasing the usefulness of the W ∗2
small quadrotor in this application. Quadcopters typically have T =
two clockwise (CW) and two counterclockwise (CCW) rotors 4
(CCW). The net center of thrust is used to regulatepitch and Where T= Total Thrust of the Motor
roll, whereas the net torque is used to control yaw.
W= Overall weight of the system
The Thrust on each of the motor is obtained as 1Kg
2) Motor: A 2212 BLDC Motor is a popular brushless DC
T =4*1 = 4 kg
motor with three phases that is extensively used in drones

and other multirotor applications. The motor has a 1000KV Ratio between the Thrust and Weight must be greater than
rated voltage and an efficiency of 80 percentage. An ESC 1 for a stable drone.
(Electronic speed controller) is required to control the speedof
the A2212 motor. With our 30A ESC, the motor can easily be 2) Selection of Battery system: The maximum current that
regulated, and when combined with our 1045 Propeller Blades, can be supplied by a battery can be given by the following
it can deliver thrust up to 800gm. Four A2212 Motors may be formula:
simply placed on the F450 Quadcopter Frame to deliver a total
thrust of 3.2kgs, allowing you to build powerfuldrones. Maximum current = capacity ∗ C − rating (3)
Maximum continuous Amp Draw= Battery Capacity X
3) Electronic Speed Controller: Tasks handled by the ESC Discharge Rate
(Electronic Speed Controller), comprises of a power The voltage requirement of the motor must meet the output
distribution stage, a current sensing circuit, a micro controller, voltage of battery
and a wired network with the remote control
3) Selection of Solar panel: The solar panel for the
4) Solar Panel: The proposed system consists of a solar proposed system is designed based on the power requirement
panel that can generate a power of 50Watts and 12 V in ideal Basically there are 3 states of motion in a quadcopter
condition. Due to various losses and instability in solar output 1. Climbing
a Boost converter is used to stabilize and step up the voltage. 2.Hovering
• Power Rating – 50 W 3. Descending
• Voltage – 24 V, Current – 2.63 A The power requirement for Hovering is given by the formulae:
• Number of Solar panels – 1 Panel
• Series – 1, Parallel – 1
5) Battery: Lithium polymer batteries are widely used for
unmanned aerial vehicle. Durability and low cost of the (4)
battery.
• Capacity: 2200 mAh
Where m= 2 kg, overall weight of the quadcopter
• Total supply voltage: 11.1V
g= 9.8 m/s2, which is acceleration due to gravity
ρ = 1.22 m/s2, which is air density
• Size: 24 x 34 x 108mm
A= 0.045 m, which is radius of the propeller
• Burst Rate: 50C
• Discharge Rate: 25 C
• Weight: 183g
• Battery type: Lithium Polymer 2200mAh 3S 25C
6) Micro Controller: A Micro controller circuitry is used
to control the system
 The power requirement for Climbing and descending is On the other side, the switch will switch to battery mode during
calculated using the formulae: off-peak hours, and output will come from the battery. So, the
quadcopter can be powered continuously for a long time by
E = m ∗g ∗h (5) balancing the power from the solar panel and batteries.
The initial model is modified in to a more sophisticated model
P = E/t (6) which forms the second section of the project. The power
where, E is the energy requirement of the motor requirement of the quadcopter varies with the application. The
P =power requirement of the motor system basically has three states of motion
m= 2 kg, o verall weight of the quadcopter • Hovering
• Climbing

g= 9.8 m/s2, which is acceleration due to gravity • Descending

h = 15 meters The important criteria for successful operation of a drone are
The power required for climbing and descending is itsstability. For a stable operation of a drone the thrust to weight
obtained 20 Watts assuming the time taken for that is ratio must be greater than or equal to 1. The thrust produced by
15 seconds. each of the BLDC motor is found to be 1 kg thus the 4 motors
will sum up to 4kg. The weight of the quadcopter drone
III. SYSTEM MODEL including the solar panel is 2kg. Thus, the thrust generated to
The paper is divided in to two parts. The initial model of the weight ratio is greater than 1.
system consists of a system that switches the power between
the solar panel and the battery based on the power available Hovering: To hover, the net thrust of the drone’s four rotors
in the solar panel as shown in Fig.2. The circuit uses a solar must equal the gravitational force dragging it down. On the
panel which gives an output of 20-30 Watts. At an irradiance of basis of equation from a paper in literature review the power
1000 watts/m2 the Boost regulator can create an output of 12 V. required by the motor for hovering is found to be 40 Watts.
To obtain a more realistic data a dataset from NASA website Climbing: The thrust force must be increased for an upward
data is taken. Figure 2 depicts the block diagram for motion. The power required for the climbing motion is derived
to be 20 Watts
Descending: The thrust force must be reduced for descending
motion and the power requirement for climbing and descending
are equal and is thus taken as 20 W.
A MATLAB model meeting the above requirement is designed
in the second section. Figure 3 represent the system model

Fig. 2. Block diagram of initial system model

the system’s initial model. The system consists of a switch,

battery, and solar panel. A signal generator transmits the data
to the solar panel. The NASA website’s data collection is used. Fig. 3. Block diagram of Final system model
The information is retrieved over 24 hours from a Tamil Nadu
site. Losses occur in the circuit; to counteract their effects and for the final proposed system. The system model includes a
stabilize the output, a boost converter is intended to supply battery, motor circuit, and solar panel. A switching circuitry
the circuit with the power it needs. A switch is attached to switches between the solar panel and the battery in the first
the solar panel’s output. In the circuitry, a 12 V, 2.2 Ah Lipo arrangement which is explained as in previous session. When
battery is utilized. The solar panel and battery work in tandem the system is switched on the data from the solar panel, battery
to deliver a steady stream of power. The circuit’s algorithm is and motor is sent to the Micro controller. Initially the micro
set up so that the switch will toggle to the solar panel and the controller compares the voltage input and compare the
solar panel will be the source of power whenever the voltage of voltage between the solar panel and the battery.
the solar panel exceeds 12 V.
 When the voltage of the solar panel is greater than 12 V, the from the solar panel is channeled between the main battery and
switch SW1 will toggle to solar output and when solar panel motor. It is seen that after 40 percent of the simulation the
output is less than 12 V the switch SW4 will be toggled to high switching was completed. When the power requirement of the
and the main battery of the system will continue to supply the motor is obtained as 40 W, the switching control was successfully
powerto motor. able to transfer the full power to the motor and when the power
requirement is only 20 W the control circuitry simulated a result
TABLE.III.A SWITCHING SCHEME OF THE PROPOSED SYSTEM by sharing the available solar power between the battery and
solar panel.
Control Vs < 12 V Vs >12 V Fig 4 represents the switching between the solar panel
Solar Panel OFF ON andthe battery. It can be inferred from the graph that when the
solar output is less than 12 V, the battery output will be used
Battery ON OFF for supplying the power for the system. At this instance the solar
power will be linearly increasing. After nearly 40 percentage of
Table III.A represents the initial switching of the system where the simulation the solar output goes high and a sudden switching
Vs represents the voltage of the Solar panel. can be seen from battery to solar panel and it continues until
When the switch SW1 is ON, the micro controller will fetch the there is constant supply of 12 V from the panel. After 70
data from motor and main battery. The power requirement by the percentage of the simulation the system again successfully
motor is evaluated by the micro controller. If the motor is in switched to battery
hovering the power requirement by the motor is 40 W. At this In the second model, multiple scenarios are taken in to
instance the switch SW3 is switched ON, channeling the full consideration based on the power requirement by the motor. The
power from the solar panel to motor. The switches SW4 and first scenario is considered when the quadcopter is hovering
SW2 is switched OFF. When the quadcopter is climbing or when the power requirement is 40 W. Fig 5 represent the
descending the power requirement is less, during this period the switching control when the quadcopter is hovering.
micro controller will initially measure the power requirement by
the motor. If the motor power requirement is less than 40 W, the
micro controller will check for the SOC ofthe main battery.
TABLE III. B. SWITCHING OF THE PROPOSED SYSTEM DURING
THE VARIOUS FLIGHTS OF MOTION
Voltage

Motor Motion SW1 SW2 SW3 SW4

Hovering ON OFF ON OFF
Climbing ON ON ON OFF
Bsoc < 80%
Climbing ON ON OFF OFF Time
Bsoc > 80%
Fig. 4. Switching between the solar panel and battery based on available voltage
Descending ON ON ON OFF with voltage on y axis and time on x axis
Bsoc < 80% .
Descending ON ON OFF OFF Fig 5.a, 5.b, 5.c charging of main battery, discharging from
Bsoc > 80% mainbattery, switching of motor respectively.

The threshold for SOC of battery is set as 80 percentage. If the

SOC of the battery is less than 80 percentagethe power from the
solar panel is shared between motor and main battery. Switches
Switching

SW2 and SW3 are switched ON at this period. When the SOC
of the battery is greater than 80 percentage, only switch SW2
is turned ON. Table III.B represents the switching of the
proposed system during the various stages of flight i.e.,
Hovering, climbing, and descending. The solar power is
completely utilized in the proposed system model. Time
Fig. 5. System switching when motor power requirement is 40 W (a)charging
IV. RESULTS AND DISCUSSION of main battery, (b) discharging from main battery, (c)powering supply to
motor
The simulation results were obtained satisfactory for varying
operating conditions with a maximum peak at 1000W/m2 and It can be found out that during the initial hours the power
at a temperature of 45 degree Celsius. The results were analyzed requirement is met by the battery. It is represented as high output
for a day from 12 AM to 12 PM. It can be found out that the in Fig 5.b. When the solar panel output is high the switch to motor
controlling system was able to successfully switch between the is turned on and it is represented as high in 5.c. After the sunshine
solar panel and battery based on the power requirement with a hours the switch will again toggle to off represented as low in the
set threshold power requirement of 40 W During the sunshine graph. At this scenario the switch to main battery is disengaged
hours which is typically around from9 AM to 5 PM the power which is represented as low in the graph 5.a. After the sunshine
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