Government College of Technology: COIMBATORE - 641 013 Project Work
Government College of Technology: COIMBATORE - 641 013 Project Work
Government College of Technology: COIMBATORE - 641 013 Project Work
PROJECT WORK
November 2021
ASWIN P
1813106
NANTHINI K
1813L07
THAMIZH MALAR MATHI T
1813154
VIKRAMAN R
1813154
of B.E. Electrical and Electronics Engineering during the year 2021 - 2022
The satisfaction and euphoria that company the successful completion of any
task would be incomplete without mentioning of the people whose constant guidance
and encouragement made it possible.
We take sincere effort to acknowledge the guidance and the advice of all the
people who have helped us in completing this project successfully.
We are greatly indebted to our Principal Dr. P. THAMARAI, Ph.D., for having
provided us with all the facilities for doing this project.
We would like to thank our loving parents for their constant support and
encouragement.
Finally, we express our gratitude to all other members who are involved either
directly or indirectly for the completion of this project.
PROBLEM DESCRIPTION
PROBLEM DESCRIPTION
The project spans over the abstract of wireless power transfer, applied to the
charging of mobile phones and other hand-held electronic devices, in improving the
transmission efficiency with magnetic field synchronous coupling and the operative
use of solar energy as the power source.
The objectives charted for the project encompasses present and future interests of
the prototype. The design and testing were formulated based on these objectives.
d) Scaling the receiver circuit as a mobilizable dongle for universal use of the
wireless charger.
e) To expend the prospects of power source from solar to dual source, i.e., Solar
and Conventional.
ABSTRACT
ABSTRACT
The usage of battery-operated electronic devices has been largely limited by their
battery capacity and the power outlets in remote locations. This project addresses
the issue of unavailability of proper power supply in remote areas and the event of
incompatibility with the available ports, with the alternative of solar charging, while
enabling the charging of a few devices by real-time conversion of solar power to
power the transmitter-receiver set up. The initial plan for the project is to develop a
wireless charging system powered by solar power to charge mobile phones. But the
system can be upscaled to charge other electronic devices such as laptops, tablets,
etc.,
The architecture of the system is broken down to PV system with MPPT for
improved efficiency, Transmission and receiver system that administers the use of
magnetic field synchronous coupling to tackle the power loss with increase in the
coupling distance, where the receiver coil that is loosely coupled with the transmitter
resonates.
The transmitter coil is driven at the same frequency i.e., the resonant frequency of
the receiver coil. For those reasons, the LC tuned circuit has been built to maintain
the same frequency. With the help of resonance phenomena, the distance between
the transmitter and receiver can be increased more than can be in the conventional
inductive-coupling Wireless Power Transfer. While improving the efficiency, this
method could be extrapolated to having universal charging systems for any kind
device, regardless of ports.
Resonance, once used on primary and secondary, power can be transferred with
very little radiated loss and 40-50% of the source power delivered to the load.
Multiple receivers could be fed from the single transmitter by using multiple resonant
peaks by resonance frequency splitting. During load shedding and travelling,
electronic devices can be easily charged without any wire and charger. One of the
main advantages include the non-radiating type of power transfer and the negligible
possibility of unintended magnetic coupling with nearby objects, with the
wavelengths on the scale of the transmitting coil. The system, not only solves the
charging issues in remote locations but also saves a considerable portion of
generated power and prevents tones of e-waste, thus being energy as well as
environmentally efficient.
TABLE OF CONTENTS
CONTENTS
CHAPTER NO TITLE PAGE NO
LIST OF FIGURES
LIST OF TABLES
LIST OF ABBREVIATIONS
1 INTRODUCTION
2 SYSTEM OVERVIEW
2.1.1 OVERALL
3 HARDWARE CONFIGURATION
3.1 MICROCONTROLLER
3.2 PV ARRAY
3.3 INDUCTOR
3.4 CAPACITOR
3.6 MOSFET
3.7 OP-AMP
3.10 RESISTOR
4 SIMULATION AND RESULTS
4.2 RESULTS
5 CIRCUIT CONFIGURATION
6 HARDWARE ASSEMBLY
6.1 OPERATION
7 FUTURE RECOMMENDATIONS
8 CONCLUSION
9 REFERENCES
LIST OF FIGURES
FIGURE NO NAME PAGE NO
2.1 Overall block diagram
2.2 MPPT Charge Controller
2.3 Power Transmission
3.1 Arduino uno
3.2 PV Panel
3.3 Inductor
3.4 Capacitor
3.5 Schottky Diode
3.6 Power MOSFET
3.7 Op-Amp
3.8 Current sensor
3.9 Voltage Sensor
3.10 Power Resistor
4.1 Simulink Model
4.2 Power Transmission
4.3 Panel Output Voltage
4.4 Panel Output Current
4.5 Battery Current
4.6 Battery Voltage
5.1 Circuit Configuration
6.1 Hardware Assembly
LIST OF ABBREVATION
ABBREVATION
INTRODUCTION
The growth in power sector, although not at sustainability, have rendered brilliant
results in the lookout for renewable energy harvesting and could be the future power
source for the entire humanity. The main attraction of the past few years, solar
energy could be the energy of tomorrow, with lesser pollution and no risk of running
out, at least in the near future.
Increase in need for electronics also increases their availability and constant
usability, i.e., infinite charging. The above ideal charging setup is being realized via
wireless charging which now can be used to charge very large loads like Electric
vehicles. Wireless charging that could offer mobility to the devices is the state of art
technology that would power the world, ideally, with no need to shut it down.
With the above considerations in mind the utilization of renewable power sources,
especially solar energy to power the wireless charging circuit, which when extended
to the charging of all hand-held devices would be a critical contributor in improving
the mobility and remove the limitations that come with cords and charging ports. The
magnetic field synchronous coupling employed in tapping the power for the load
enables the system to operate at maximum efficiency, directly following the MPPT
algorithm employed. The method also keeps open the future enhancements in
universalizing the operating frequency of the transmitter-receiver pair, thus creating
a universal charger for all kinds of handheld devices.
SYSTEM OVERVIEW
CHAPTER 2
SYSTEM OVERVIEW
2.1. BLOCK DIAGRAM
2.1.1. OVERALL
Figure 2.1 depicts the block diagram of the proposed project. This block
diagram mainly consists of seven parts. This includes
PV Panel
MPPT Charge Controller (Arduino Uno)
Battery
Transmitter and Receiver circuit
Voltage Regulator
Rectifier
Figure 2.2 depicts the block diagram of the MPPT Charge Controller. This
block diagram mainly consists of seven parts. This includes
Current Sensor
Voltage Sensor
Buck Converter
Arduino UNO
Battery
Through dc-dc optimizers, localized control of panel voltage and current can be
achieved, and each panel can operate at its independent maximum power point
(MPP), thus improving the energy extraction of the overall system. The series
connection of the outputs provides an inherent voltage stacking that enables each
dc-dc converter to operate at a relatively low voltage conversion ratio (enabling high
conversion efficiency), while still achieving high overall output voltage, which is
desirable as it enables the use of a central, high-voltage, high-efficiency inverter.
Figure 2.3 depicts the block diagram of the Transmission Circuit. This block
diagram mainly consists of seven parts. This includes
555 Timer
Switching Circuit
Transmitter and Receiver Coil
Rectifier
HARDWARE CONFIGURATION
3.1. MICROCONTROLLER
Our project required a device that can control the duty cycle (modify the pulse
width of a square wave) based on the Panel Output power. This square wave signal
is sent to the MOSFET which acts as an electronic switch, which affects the buck
converter output voltage. A microcontroller is used to partially serve these purposes.
It calculates the power from the samples of the voltage and the current at every
instant from the panel. By comparing a previous power to a new power, an
appropriate modification of duty cycle would occur and so a change in PWM would
happen. A microcontroller was chosen rather than a microprocessor because it
required less external hardware, reducing the final product size. Being compact
makes it very efficient.
3.1.1 Arduino
3.2. PV ARRAY
The most widely used types of crystalline silicon used in solar panels are
mono-crystalline and Polycrystalline. Mono-crystalline not the most commonly used
but this technology is one of the oldest and most proven in comparison to the rest.
As the name implies this type of solar cells are made from the same silicon crystal,
which is very pure and has less irregularities and imperfections than polycrystalline
solar cells. Polycrystalline solar panels are the most common type of solar today,
due to their low cost and average power efficiency.
Efficiency is the main disadvantage of polycrystalline solar panels. They convert only
10%-14% of the solar energy that hits their surface. Efficiency for these solar panels
drops in comparison to their mono-crystalline counterpart because of the energy loss
at the separation or fusion points between two adjacent crystals. Thus, the choice of
selection, Panel with 20V open circuit voltage and short circuit current 1.44A capable
of producing 20 W at maximum power point (MPP).
3.3. INDUCTOR:
Ld i L
V=
dt
D
∆ I L =( V G−V O ) T
L SW
From the steady state inductor current waveform, it can be easily deduced the
change in inductor current is its slope times the length of subinterval. The ripple
requirement in inductor current sets the inductor value. Typically, ∆IL lies in the range
of 10-20% of the full load or maximum value of the DC component of I O. The peak
inductor current which is equal to the DC component plus the peak to average ripple
∆IL/2, flows
3.4. CAPACITOR:
The only steady state component of output capacitor current is that arising
from the inductor current ripple. Here inductor current cannot be neglected when
calculating the Output voltage ripple. The inductor current contains both a DC and
ripple current component. The DC component must flow entirely through the load
resistance R. While the AC switching ripple divides between the load resistance R
and the filter capacitor C.
1
ZR ,C =RC +
C
jωC
|Z R , C|=
c
√ Rc +
2
1
ω C2
2
To ensure minimum ripple at rated output load, the equivalent condition states that
the series R-C branch impedance appear resistive over the frequency band of
switching component. This is the condition of minimum ripple and is a reason for
requiring low ESR.
1
Rc + 2 2
≪R
ω C
2
C ≫ ω(R 2−Rc ) 2
The output voltage ripple requirement puts an upper bound on capacitor ESR. Thus,
the voltage ripple peak magnitude is estimated by
∆ IL
∆ V =∆ I L R c +
8 C f sw
∆ V =∆ I L R c
With the ESR requirement met, the capacitance value can be selected to achieve
adequate filtering. Capacitors are typically paralleled to meet the ESR requirement.
An alternate approach to reduce ΔV is to reduce ΔI but this requires a larger value of
the inductor.
Schottky Diode completes the loop of current when MOSFET is switched off and
thus ensuring smooth supply of current to load. Apart from this, Schottky diode
dissipates very low heat, has low forward voltage and work fine at higher frequency
than regular diodes.
Figure 3.5. Schottky diode
3.6. MOSFET
The IRFZ44N is a N-channel MOSFET with a high drain current of 49A and low R ds
value of 17.5 mΩ. It also has a low threshold voltage of 4V at which the MOSFET
will start conducting. Hence it is commonly used with microcontrollers to drive with
5V. However, a driver circuit is needed if the MOSFET has to be switched in
completely.
Figure 3.6. Power Mosfet
3.7. OPAMP
It can be considered as one half of LM324 Quad Op-Amp which contains four Op-
Amps with common power supply. The differential input voltage range can be equal
to that of power supply voltage. The default input offset voltage is very low which is
of magnitude 2mV. The typical supply current is 500μA independent of the supply
voltage range and a maximum current of 700μA. The operating temperature ranges
from 0˚C to 70˚C at ambient whereas the maximum junction temperature can be up
to 150˚C.
Figure 3.7. Op-Amp
The field then causes the electrons to "push" to one side of the plate and produce a
voltage difference between the two sides. The difference in voltage from the side of
the plate is the output of the sensor. ACS712 sensor have been used in our case,
which can operate on both AC and DC. This sensor operates at 5V and produces an
analog voltage output proportional to the measured current and capable of
measuring up to 5A.
3.10. RESISTOR
The Resistor that’s been used in the circuit is power resistor of value 10 Ω
having power rating of 20W. Power resistors are resistors that are designed to
withstand and dissipate large amounts of power. The common trait of all power
resistors is that they are built to dissipate as much power as possible, while keeping
their size as small as possible. There are several types of Power resistors, Wire
wound resistor are ones we used. Wire wound resistors are made by winding a
metal wire around a solid form, often made of ceramic, fiberglass, or plastic. Metal
caps are attached to the end of the winding and metallic leads are attached to the
ends. The end product is often coated with a non-conductive paint or enamel to offer
some protection from the environment. Wire wound resistors can be built to
withstand high temperatures, sometimes up to 450 °C. These resistors are often
built to tight tolerances thanks to the material used, an alloy of nickel and chrome
called Nichrome. The body of the device is then coated with a non-conductive paint,
enamel, or plastic.
The primary half of the circuitry is the DC-DC converter design to draw maximum
output from the PV array. The buck-boost converter adopted for executing the MPPT
algorithm retains the operating point near the Maximum Power Point in conditions
where the PV panel output falls above or below the required output voltage with the
help of MPPT algorithm block, which functions in place of a microcontroller in real
time. The algorithm enables both buck and boost mode, consistently tracking the
operating point and adjusting it by altering the duty cycle.
To imitate real time, the PV panel takes both irradiance and temperature as input.
The depicted circuit takes a constant irradiance input but can be modeled to accept
variable irradiance to mimic an available dataset. The converter circuit charges the
battery, which is essentially an ideal, lossless load in the simulation and the system
achieved
The power transmission unit for the wireless transmission using resonance coupling
is realized with the help of MATLAB – Simscape to replicate the real-world
conditions. Simscape is a physical modelling environment that provides the user with
the option to create non-ideal version of the components used and a wide range of
customization parameters.
The blocks imitate the physical characteristics of the elements including their lossy
behavior. The 555-timer block works in the place of a 555 timer IC to drive the
MOSFET and has a variable input characteristic to be able to model it with respect
to the design of voltage regulator circuit. The transmitter – receiver unit is a mutually
coupled inductor with multitude of variable parameters including impedance,
inherent capacitance, resistance and coupling factor. The function of the block
parameter traces promptly by the real-world operation and does suffer a loss on the
receiver side, owing to the internal resistance loss in the battery.
After the losses and rectification, the resonant circuit delivers a power in the order of
milliwatts, which is one of the scopes of our future research on reducing internal
resistance drop.
4.2. RESULTS
Solar battery charger with MPPT tracking has been implemented in real time
with the help of a DC-DC converter. The converter adopted for the realization is a
DC-DC buck converter, whose maximum power point has been achieved with the
help of a solar emulator under lossy condition.
The Solar PV panel is of polycrystalline variety and is suitable for use in rugged
conditions with life as long as its monocrystalline counterpart. It also pulls close to its
maximum operating capability even under low light conditions.
The MOSFET IRFZ44n was chosen for its high-power withstanding capability. It is
worth mentioning that since this model is an N-channel MOSFET it has
comparatively lower loss characteristics and optimizes the circuit operation. The high
input impedance of the MOSFET prevents the loading of op-amp and thus the need
for resistance grounding in the op-amp output.
FUTURE RECOMMENDATIONS
CHAPTER 7
FUTURE RECOMMENDATIONS
The project was adopted with aim of exploring the current extent of technological
limits in realizing a wireless power transmission unit and in zeroing in on the future
prospects in wireless power transmission.
CONCLUSION
Magnetic resonant coupling can be used to deliver power from a large source
coil to one or many small load coils, with lumped capacitors at the coil terminals
providing a simple means to match resonant frequencies for the coils. This
mechanism is a potentially robust means for delivering wireless power to multiple
receivers from a single large-source coil.
A relatively simple circuit model describes the essential features of the resonant
coupling interaction, with parameters that can be either derived from first principal
descriptions, from direct measurement or from curve fitting techniques.
Wireless transmission by this mode could become the base of wireless transmission
across longer distances since the demonstrated method of power transfer requires
not coaxial arrangement, but line of sight, a feature that could be exploited across
kilometers. Although the kilometer range could be in the far future, this method’s
immediate successor could be the powering of small electrical and electronic
devices around the residential area.
This project is but a simple demonstration of wireless power transfer aiming at near
field non-radiative transfer with improved efficiency since the coupling factor plays a
major role in the transmission distance and the coil arrangement. The ability of this
system to work on and off grid enables it to be available round the clock as a reliable
source of charging that facilitates mobility and energy conservation. The non-
radiative method of power transfer is environmentally friendly and free of health
hazards, thus poses no threats to the lifeforms interacting with the field.
REFERENCES
CHAPTER 9
REFERENCES
2) Fei Zhang and Mingui Sun, "Wireless Power Transfer with Strongly Coupled
Magnetic Resonance", Departments of Neurosurgery and Electrical
Engineering, University of Pittsburgh, USA, ISSN: 3002-0522
5) Jiang, Chaoqiang et al. "An Overview of Resonant Circuits for Wireless Power
Transfer." Energies, ISSN: en10070894
6) Phinney, J., and D.J. Perreault. “Filters with Active Tuning for Power
Applications.” IEEE Trans. Power Electron. 18, no. 2 (March 2003):636–647
APPENDIX
CHAPTER 10
APPENDIX
10.1 ARDUINO PROGRAM
void setup() {
Serial.begin(9600);
pinMode(9, OUTPUT);
pinMode(A2, INPUT);
pinMode(A1, INPUT);
pinMode(A0, INPUT);
TCCR0B = TCCR0B & B11111000 | B00000010;
}
void loop() {
TCCR0B = TCCR0B & B11111000 | B00000010;
//Current
int pwmnew=0;
unsigned int x = 0;
float AcsValue = 0.0, Samples = 0.0, AvgAcs = 0.0, AcsValueF = 0.0, valu=0;
for (int x = 0; x < 150; x++) { //Get 150 samples
AcsValue = analogRead(A1); //Read current sensor values
Samples = Samples + AcsValue; //Add samples together
delay (3); // let ADC settle before next sample 3ms
}
AvgAcs = Samples / 150.0;
AcsValueF = (((2.5 - (AvgAcs * (5.0 / 1024.0)) )/0.066));
Serial.print("current");
Serial.print(AcsValueF); //Print the read current on Serial monitor
delay (50);
//Voltage
adc_value = analogRead(A0);
adc_voltage = (adc_value * ref_voltage) / 1024.0;
in_voltage = adc_voltage / (R2 / (R1 + R2));
Serial.println("Input Voltage = ");
Serial.print(in_voltage, 2);
delay(500);
voltageValue=in_voltage;
currentValue=AcsValueF;
Power_now = abs(voltageValue * currentValue);
//Power and duty
if (Power_now > Power_anc)
{
if (voltageValue > voltage_anc)
pwm = pwm + delta;
else
pwm = pwm - delta;
}
else
{
if (voltageValue > voltage_anc)
pwm = pwm - delta;
else
pwm = pwm + delta;
}
Power_anc = Power_now;
voltage_anc = voltageValue;
if (pwm < 40)
pwm = 40;
if (pwm > 250)
pwm = 250;
pwmnew = 255 - pwm;
analogWrite (9, pwmnew);
Serial.println ("PWM: ");
Serial.print (pwmnew);
Serial.println (" ");
}