MENSCHEN FÜR MENSCHEN FOUNDATION

AGRO-TECHNICAL AND TECHNOLOGY COLLEGE

EL ECTRICAL AND ELECTRONICS TECHNOLOGY
DEPARTMENT
POWER AND CONTRPOL STREAM
COURSE TITLE: ENERGY CONVERSION AND RULAR

ELECTRIFICATION
COURSE CODE: EET 4324
GROUP 2
PROJECT TITLE: MODEL AND SIMULATION OF SOLAR SYSTEM
FOR MFM ATTC PRINTING HOUSE

PREPARED BY:
NAME ID.NO.

1. BEYENE DUGUMA………….……………ATTC/047/21

2. FARAHAN ABDULKADIR…..…………...ATTC/094/21

3. GUTA CHALA………………………….....ATTC/121/21

4. HABTAMU BEGNA…..…….……………ATTC/1 23/21

5. SAMIYA ABDUSAMAD……………..…..ATTC/174/21

6.TARIKU BERHANU..……………….…….ATTC/188/21

PROJECT SUBMITTED TO: SEMIRET MINDA (MSc.)

SUBMISSION DATE: JUNE 7 2024

HARAR ETHIOPIA

JUNE,2024 GC

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 Acknowledgement
Firstly and our most profound gratitude goes to the almighty God for the gift of life and good
health in the actualization of this work. Without him at our side we would not have been able to
complete this project. It was amazing to sharing each moment along side all of you. A special
thanks to our Teacher Mrs. Simeret Minda and Mr. Hamdi Mohamed (our advisor) to give for
this opportunity, the valuable comments and suggestions. We have grateful for Menschen Fur
Menschen, Electrical and Electronics Technology Department and ATTC photocopy Center
stuffs for letting us all information of the center. Finally, we acknowledge all other who have
helped us and whose names could not be accommodated in this brief acknowledgment.

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 Contents

ACKNOWLEDGEMENT............................................................................................................................................. I

CONTENTS……………………………………………………………………………………………………………………..II

LIST OF FIGURE........................................................................................................................................................ IV

LIST OF TABLES......................................................................................................................................................... V

ABSTRACT................................................................................................................................................................... VI

CHAPTER 1: INTRODUCTION.............................................................................................................................. 1

1.1 Background.............................................................................................................................. 1

1.2 Problem statement..................................................................................................................2

1.3 Objective..................................................................................................................................2
1.3.1 General objective.............................................................................................................. 2
1.3.2 Specific objectives............................................................................................................. 2

1.4 Scope of the study.................................................................................................................. 3

1.5 Significance of the study......................................................................................................... 3

CHAPTER 2: THEORETICAL BACKGROUND..................................................................................................4

2.1 Literature review..................................................................................................................... 4

2.2 Basic theories of solar power system.......................................................................................5

2.3 System components.................................................................................................................5

2.3.1 Solar panels (PV Modules).................................................................................................5
2.3.2 Boost converter.................................................................................................................9
2.3.3 Power inverter................................................................................................................ 11
2.3.4 Batteries.......................................................................................................................... 11

2.4 Maximum power point tracking (MPPT)...............................................................................12

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 2.4.1 Incremental conductance................................................................................................13

CHAPTER 3: MATERIAL AND METHOD........................................................................................................16

3.1 Load Estimation and power consumption.............................................................................16

3.1.1 Calculating Power Consumption.....................................................................................16

3.2 Cost estimation...................................................................................................................... 21

CHAPTER 4: SIMULATION OF PV POWER SYSTEMS..............................................................................22

4.1 MATLAB Modelling of PV system...........................................................................................22

4.2 Simulation result....................................................................................................................24

CHAPTER 5: CONCLUSION AND RECOMMENDATION..........................................................................26

5.1 Conclusion............................................................................................................................. 26

5.2 Recommendation...................................................................................................................26

REFERENCES............................................................................................................................................................ 27

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 List of Figure
Fig.1. Basic diagram of Photovoltaic current generation................................................................6
Fig.2.Design of PV array from PV cell...........................................................................................6
Fig.3. Equivalent circuit of a PV Cell..............................................................................................7
Figure 4. I-V Curve and P-V curve of PV panel.............................................................................8
Figure 5- Elementary circuit of Boost Converter............................................................................9
Figure 6. DC to DC Boost Converter Continuous Conduction Mode Circuit.................................9
Figure 7. DC to DC Boost Converter Discontinuous Conduction Mode Circuit..........................10
Figure 8. Wave form representation..............................................................................................10
Figure 9. Solar battery...................................................................................................................12
Figure 10. Block of solar panel with MPPT..................................................................................13
Figure 11. Graph of solar output with MPPT................................................................................14
Figure 12: Flow chart of incremental conductance algorithm.......................................................14

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 List of Tables
Table 1: Load estimation...............................................................................................................16
Table 2: Inverter power.................................................................................................................17
Table 3: Inverter energy.................................................................................................................17
Table 4: Controller power rating...................................................................................................17
Table 5: Battery size......................................................................................................................18
Table 6: Depth of Discharge..........................................................................................................19
Table 7: Energy of SPV.................................................................................................................19

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 ABSTRACT
This paper presents the design and simulation of a photovoltaic system using incremental
conductance Maximum Power Point Tracking (MPPT) algorithm to generate electrical power
from the Photo-Voltaic System (PVS) solar panels for ATTC photocopy house. In order to get
maximum power from the solar panels the Maximum Power Point Tracking (MPPT) controllers
can play an important role in photovoltaic systems, they have to operate at their maximum power
point (MPP) despite the changes in the environment conditions. Maximum Power Point Tracking
(MPPT) which significantly increases the efficiency of the solar photovoltaic System. There are
different MPPT control methods used for solar PV systems, Incremental conductance(IC),
Perturb and observe(P&O), Constant Current method, Constant Voltage method, Fuzzy Control,
and Neural Network Control. This paper presents the modeling and simulation of incremental
conductance MPPT algorithm for PV array using boost converter. The simulation has been
accomplished using MATLAB.

Keywords - Photovoltaic (PV) System, Maximum Power Point Tracking (MPPT),

Maximum Power Point(MPP), Incremental Conductance method(IC).

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 Chapter 1

Introduction
1.1 Background

Energy is essential to economic and social development and improves quality of life. It is very
important for the developing society. it plays a role in the development of society, impacting
economic growth, infrastructure development, quality of life, environmental sustainability, social
equity, and technological innovation.

Nowadays demand of electric power is very increase day to day. To fulfill the demand traditional
generating system is not enough because the input fuel cost is very high and these fuels are
limited in nature. Due to these reasons is necessary to shift from using these traditional
generators to the use of renewable energy technologies. The major advantage with renewable
power resources is that it is free and unlimited in nature. Solar energy is one of the renewable
energy which is widely used for power generation.

The Solar Photovoltaic (SPV) systems convert sunlight into electricity using photovoltaic cells
with no pollution, no maintenance and no depletion of natural resources;. These systems consist
of solar panels, inverters, mounting structures, and other components that work together to
generate electricity from sunlight. The solar panels contain photovoltaic cells made of
semiconductor materials, such as silicon, that absorb sunlight and convert it into direct current
(DC) electricity.

Generally a PV Cell generates a voltage around 0.5 to 0.8 Volts depending upon on material and
it’s built up technology. This voltage is not enough to use in practice. So, to get benefit from this
technology, tens of PV cells (involving 36 to 72 cells) are connected in series to form a PV
module. These modules can be interconnected in series and/or parallel to form a PV panel. With
the rapid increment in Solar Power generation in grid connections and also in standalone
conditions, it should require a technique to solar power conversion to track the maximum power
from the solar radiation. This paper mainly focuses on the design and simulation of PV System
with Incremental Conductance method to achieve the maximum power in MATLAB.
1.2 Problem statement

Electrical power can be converted to into different forms. So it is reliable energy form. Since in
our compound electric power is provided in hybrid system (i.e. from grid and Diesel Generator).
Being source of clean energy, produce electrical energy anywhere sunlight exist and low
maintenance cost, make solar energy reliable. There are some disadvantages of PV panels,
conversion of energy is low (9-16%) and the electrical characteristic of PV panels change under
variable weather conditions.

Diesel Generator requires diesel fuel to continuously. However the cost of diesel is increasing
time to time. In order to minimize this time varying cost renewable energy source can be taken to
account. One of the renewable energy source and can be found in abundant is sunlight .so using
it will minimize this cost considerably.

1.3 Objective

1.3.1 General objective

The objective of this design and simulate a solar photovoltaic (SPV) system for MMF ATTC
photocopy house using incremental conductance MPPT method.

1.3.2 Specific objectives

The specific objectives of this study are:

 To collect load data from the site including their types, power rate and their number.
 To estimate the load total energy.
 To size, design and select each components.

 To design battery required to use as a storing part of the system

 To model and estimate the cost required to design and run the system
 To design an SPV system with appropriate capacity to meet a significant requirement
energy.
 To implement the incremental conductance MPPT algorithm to ensure maximum power
extraction from the solar panels under varying environmental condition.
 To conclude and recommend the result obtained from the simulation.

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1.4 Scope of the study

This solar power source makes it possible to provide a clean reliable supply of alternative
electricity free of sags or surges which could be found in the line voltage frequency. The solar
power system (SPS) system achieved this by direct current from solar panel and by rectifying the
standard main supply, using the direct current to charge the batteries and to provide clean
alternative power by passing the energy a filter system. It has zero change over time and LEDs
which indicates mains fail and battery discharge level and it provides 100% protection against
line noise, spikes surges and audio frequency interference.

1.5 Significance of the study

The significance of this study is increasing the demand for renewable energy source and need for
efficient SPV system. to examine the feasibility of implementing PV systems for ATTC
photocopy house. As well as to implement the PV-system to reduce the discontinuous of electric
power and to get maximum power.

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 Chapter 2

Theoretical Background
2.1 Literature review

The Harar ATTC College in Ethiopia has been exploring the use of solar photovoltaic (SPV)
systems to meet its energy needs and reduce its carbon footprint. Ethiopia has significant
potential for solar energy development, with an average daily solar radiation of 5-7 kWh/m2
across the country. The use of SPV systems has been gaining traction in the country, particularly
in off-grid and rural electrification projects.

One of the key challenges in optimizing the performance of SPV systems is the implementation
of effective maximum power point tracking (MPPT) algorithms. The incremental conductance
MPPT method has been widely studied and applied in the context of SPV systems in Ethiopia.
This method is based on the principle that the derivative of the power with respect to the voltage
(dP/dV) is equal to zero at the maximum power point (MPP). By continuously monitoring the
voltage and current of the SPV array, the algorithm can adjust the duty cycle of the DC-DC
converter to track the MPP and maximize the power output.

Several researchers have investigated the performance of the incremental conductance MPPT
method in SPV systems under the specific environmental conditions and challenges faced in
Ethiopia. For example, Bekele and Palm developed a simulation model of a SPV system with an
incremental conductance MPPT algorithm and evaluated its performance under varying solar
irradiance and temperature conditions typical of the Ethiopian climate. They found that the
incremental conductance algorithm was able to effectively track the MPP and maximize the
power output under these conditions.

Similarly, Asfaw and Alemayehu conducted a comparative study of different MPPT algorithms,
including the incremental conductance method, for a SPV system in Ethiopia. They found that
the incremental conductance algorithm outperformed other methods in terms of tracking
efficiency and power output, particularly under rapidly changing environmental conditions.

In the context of the Harar ATTC College, the design and simulation of the SPV system
components, such as the DC-DC converter, the inverter, and the load, have also been studied.
Researchers have focused on optimizing the system's performance and efficiency to meet the
specific energy demands and grid integration requirements of the college.

For instance, Gebremedhin and Kebede designed and simulated a SPV system with a boost
converter and a three-phase inverter for a rural electrification project in Ethiopia. They analyzed
the system's performance under different load conditions and grid integration scenarios, which
could be applicable to the Harar ATTC College's energy needs.

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Overall, the literature review highlights the importance of the incremental conductance MPPT
method in maximizing the power output of SPV systems in the Ethiopian context, particularly
for institutions like the Harar ATTC College. The review also emphasizes the need for
comprehensive design and simulation studies to optimize the system's performance and address
the specific challenges faced in the region.

2.2 Basic theories of solar power system

The development of new energy sources are continuously enhanced because of the critical
situation of the chemical industrial fuels such as oil, gas and others. Thus, the renewable energy
sources, like solar, wind ,hydro, biomass etc... have become a more important contributor to the
total energy consumed in the world.

Solar energy is primarily transmitted to the Earth by electromagnetic waves, which can also be
represented by particles (photons). Sunlight is by far the largest carbon-free energy source on the
planet. Electricity can be produced from sunlight through a process called the photo voltaic (PV)
effect, where” photo” refers to light and “voltaic” to voltage. The term describes a process that
produces direct electrical current from the radiant energy of the Sun. The PV effect can take
place in solid, liquid, or gaseous material; however, it is in solids, especially semiconductor
materials, that acceptable conversion efficiency have been found. Solar cells are made from a
variety of semiconductor materials and coated with special additives. The most widely used
material for the various types of fabrication is crystalline silicon, representing over 90% of
global commercial PV module production in its various forms. A typical silicon cell, with a
diameter of 10 cm., can produce more than 1 W of direct current (DC) electrical power in full
sun. Individual solar cells can be connected in series and parallel to obtain desired voltages and
currents. These groups of cells are packaged into standard modules that protect the cells from the
environment while providing useful voltages and currents.

A typical solar power supply device is comprised of solar panel, a charge controller, a power
inverter having a meter or monitoring system which is capable of monitoring voltages and
system condition and the electrical distribution system.

2.3 System components

2.3.1 Solar panels (PV Modules)

A solar panel is a device that is able to absorb sun rays and convert it into electrical energy
precisely DC. The photovoltaic panel comprised of silicon crystals, which reacts with sun ray
and under this process, converts the sun rays into electricity. They supply the electricity for
charging the batteries and for use by the appliances either directly or through an inverter.
Multiple modules where used to produce more electricity and then any excess energy that was
produced was stored in the batteries for use during the cloudy/ rainy weather. The panels are

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available in different sizes, voltages and amperage. They can be wired in series or in parallel
depending on how the system is designed.

Fig.1. Basic diagram of Photovoltaic current generation

Generally a PV Cell generates a voltage around 0.5 to 0.8 Volts depending upon on material and
it’s built up technology. This voltage is not enough to use in practice. So, to get benefit from this
technology, tens of PV cells (involving 36 to 72 cells) are connected in series to form a PV
module. These modules can be interconnected in series and/or parallel to form a PV panel.

I. Modelling of PV array
Solar cell being a semiconductor device made of silicon, gallium arsenide etc produces direct
current and power. It converts sunlight directly into electricity. The PV modules connected in
series and parallel to generate the desired power. The voltage produced depends on solar
irradiance and temperature. The equivalent circuit of a solar cell consists of a diode (Fig. 2) and a
current source which are connected in parallel along with series and shunt connected resistances.
Here the current source represents the generated photo current when sun light hits the PV cell.
Fig.3. Shows the simulink model of a PV cell. The losses due to the body of the PN
semiconductor and contacts are modeled as shunt and series resistances respectively. The voltage
and current relationship in the simplified solar cell model can be derived from KCL and KVL.

PV array model designed from the simple PV cells. In this way PV array has been assumed to
comprise a combination of Ns cells in series and N p cells in parallel in order to achieve the
required output. The Fig.2 gives an idea of designed PV array from a PV cell.

Fig.2.Design of PV array from PV cell

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A simple solar PV panel consists of several p-n junction that on interaction with the solar
radiation release electrons which is called as photovoltaic effect. For the perfect study of method
to improve efficiency of PV panel it should be modeled as the equivalent circuit for calculation
purpose shown in fig 3. It can be ideally modeled as the current source in parallel with forward
biased diode. But practically the panel also produce losses, so the representation is added with a
series resistance Rs which is very small indicates the ohmic contact between the metal and
semiconductor internal resistance. Also paralleled resistor Rp is added indicating the surface
quality along the module’s periphery. It also represents impact of shading and is generally very
high. Commercially, value of Rp is much greater than forward resistance of diode.

Fig.3. Equivalent circuit of a PV Cell

The mathematical model of a PV cell is described by following equation:

Observations from the above two equations are

ID= Diode Current (A)

IO =Diode saturation current (A)

q= Electron charge (Jouls)

IL = Generated light current (A) International

K= Boltzman constant (J/K)

T= Temperature of cell (K)

V= Output voltage of cell (V)

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The output current I can be determined by combining the above equations in I. It take into
account different properties of solar cell as: The power dissipation across internal resistances
affects efficiency as well as maximum output power of solar cells. The maximum power as well
as the cell efficiency reduced with increasing value of series resistance for both models. Rs is
introduced as to consider the voltage drop across and internal losses due to the current flow, Rp
is taken into account of the leakage current to the ground when diode is reverse biased. The
characteristics equation of the solar module depends on the number of cells arranged in parallel
and in series. It is observed that the variation of current is less dependent on the shunt resistance
and more dependent on the series resistance.

The power-voltage curve and current-voltage curves of a solar cell mainly depends on the solar
irradiation value and a negative impact on the power generation capability is observed when
temperature around the solar cell increases. The solar irradiation as a result of environmental
conditions keeps on varying, but various control mechanisms are available that can track this
change and can alter the further processing of the solar cell to meet the required demand of loads.
Higher is the solar irradiation higher is the solar input and hence power magnitude would
increase for the same voltage value. On the other side the band gap of the material is more when
the temperature is increased and a decrease in open circuit voltage value is observed. As band
gap increases more energy is required to cross the barrier and hence the efficiency of the solar
cell is decreased.

Figure 4. I-V Curve and P-V curve of PV panel

The I-V characteristic of a PV array under constant irradiance has a unique point, called
maximum power point (MPP) at which the array reaches the maximum power for given
conditions. The quality of the cell is indicated by the term fill factor (FF), which is the ratio of
maximum power that the solar cell can provide under normal operating conditions to the product
of the open circuit voltage and short circuit current. An ideal solar cell will have a fill factor of
unity, i.e. give maximum power. The normal percent efficiency is determined by taking the ratio
of maximum power the solar cell can produce to the amount of solar irradiance hits in the solar

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cell. The cell conversion efficiency is determined by taking the ratio of electrical power output to
incident solar power. Various loss mechanisms limit the conversion efficiency of the solar cell
and the major cause of the losses are due to:

1. Inherent nature

2. Energy distribution of incident photons.

2.3.2 Boost converter

Boost Converters sometimes, also known as step-up choppers are the type of chopper circuits
that provides such an output voltage that is more than the supplied input voltage. In the case of
boost converters, the dc to dc conversion takes place in a way that the circuit provides a high
magnitude of output voltage than the magnitude of the supply input. It is given the name ‘boost’
because the obtained output voltage is higher than the input voltage.

Operating Principle of Boost Converter

The low input DC voltage is converted into high output DC voltage using DC to DC boost
converter. As the input voltage is stepped up compared to output voltage, hence, it is also called
as a step up converter. Generally, DC to DC converters can be designed using power
semiconductor switching devices and discrete electrical and electronics components.

Figure 5- Elementary circuit of Boost Converter

In DC to DC converter, the converter operates in two modes:

 Continuous Conduction Mode

 Discontinuous Conduction Mode

Figure 6. DC to DC Boost Converter Continuous Conduction Mode Circuit

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The continuous conduction mode circuit of the DC to DC boost converter is shown in the figure
that consists of an inductor, capacitor, switching device, diode, and input voltage source. This
boost converter circuit switch is controlled using a pulse width modulator (PWM). If this switch
is in ON state, then energy will be developed in the inductor and thus more energy will be
delivered to the output.

Figure 7. DC to DC Boost Converter Discontinuous Conduction Mode Circuit

The discontinuous conduction mode circuit of the DC to DC boost converter is shown in the
figure that consists of elements such as capacitor, inductor, voltage source, diode, and switching
device. In this discontinuous conduction mode, if the switch is in ON state, then energy will be
delivered to the power storage element, inductor. If the switch is in OFF state for some period,
then the inductor current will reach zero until the next switching cycle is on. Thus, the capacitor
gets charged and discharged with respect to the input voltage. But, here the output voltage in
discontinuous conduction mode is less than the output voltage in continuous conduction mode.

Similarly, buck converters are used for converting high input DC voltage into low output DC
voltage. Buck-boost converters are used for maintaining output DC voltage high or low based on
the input DC voltage source. If the input DC voltage is high, then the output will be low and
vice-versa. Thus, we can maintain regulated DC voltage using buck-boost converters.

Figure 8. Wave form representation

In the above output waveforms we have got two time periods Ton and T off. Ton is the time period
at which the transistor is turned ON and T off is at which the transistor is turned OFF. We can see

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that during the Ton period the transistor output voltage Vo will be zero I L will start to increase
from Imin to Imax and the diode current will be zero.

2.3.3 Power inverter

The inverter convert the DC voltage produced by the solar panels (and from the energy stored in
the batteries) into AC voltage. The inverter could also charge the batteries by using an alternative
source such as the mains or generator connected to the inverter when they are available.
Choosing the right inverter for the load demand and power requirements of the system was
critical for the components to function properly.

2.3.3.1 Inverter Sizing

An inverter uses the (DC) direct current power supply and creates an alternating current (AC)
supply usually at the voltage similar to that of a normal mains power supply. In other words, it
enabled the running household appliances from a low voltage DC supply such as a solar battery
as the heart of the system. Inverter sizing was considered before purchasing the inverter, while
sizing the inverter, two figures were looked at

1. The continuous wattage output

2. The surge capacity. The inverter was selected observing the largest load to be operated at one
time.

2.3.4 Batteries
Battery capacity is defined as the total amount of electricity generated due to electro-chemical
reactions in the battery and is expressed in ampere hours. The capacity of a battery, whether
rechargeable or non-rechargeable is most commonly measured in amp hours or milliamp hours.

Typically amp hours are used for much larger items such as car batteries or many other electrical
items where the current is measured in amps, the units will be amp-hours. For smaller items like
batteries used for powering electronic equipment, the capacity is typically measured in milliamp-
hours - although sometimes these figures may exceed 1000 milliamp hours, but it is less
confusing to do that than have some batteries of a certain type measured in milliamp hours and
others in amp hours.

The runtime of an inverter powered by batteries is dependent on the battery power and the
amount of power being drawn from the inverter at a given time. As the amount of equipment
using the inverter increases, the runtime will decrease. In order to prolong the runtime of a
inverter, additional batteries can be added to the inverter.

Formula to calculate inverter battery capacity

Total Load (¿ watts)∗usage Time(¿ hours)

Battery capacity (Ah)=
Input voltage (V )

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 Figure 9. Solar battery
When attempting to add more batteries to an inverter, there are two basic options for installation.

i. Series configuration
If the goal is to increase the overall input voltage to the inverter, one can daisy chain batteries in
a series configuration. In a series configuration, if a single battery dies, the other batteries will
not be able to power the load.

ii. Parallel configuration

If the goal is to increase capacity and prolong the runtime of the inverter, batteries can be
connected in parallel. This increases the overall ampere hour (Ah) rating of the battery set. If a
single battery is discharged though, the other batteries will then discharge through it. This can
lead to rapid discharge of the entire pack, or even an over-current and possible fire. To avoid
this, large paralleled batteries may be connected via diodes or intelligent monitoring with
automatic switching to isolate an under-voltage battery from the others.

The lead–acid battery is a type of rechargeable battery first invented in 1859 by French
physicist Gaston Plante. It is the first type of rechargeable battery ever created. Compared to
modern rechargeable batteries, lead–acid batteries have relatively low energy density. Despite
this, their ability to supply high surge currents means that the cells have a relatively large power-
to-weight ratio. These features, along with their low cost, make them attractive for use in motor
vehicles to provide the high current required by starter motors.

2.4 Maximum power point tracking (MPPT)

MPPT or maximum power point tracking is the technique commonly used in solar systems to
extract maximum power under all weather conditions. In this tracking no mechanical equipment
is included. It is totally electronic based system. In this system various electronic components are
used to track the MPP by varying the electrical parameters of the module. MPPT system mainly
includes the charge controller which observes the output of the solar panel and compares it to the
battery voltage and selects the best power that can be match the requirement of the battery or the
utility grid. The proposed block diagram of MPPT is shown in fig 10.

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 Figure 10. Block of solar panel with MPPT
There are various MPPT methods developed till now such as the perturbation and observation
(P&O) technique, the incremental conductance (Inc Cond.) technique, ripple correlation
technique, short circuit current (SCC) technique, and open circuit voltage (OCV) technique.
Earlier the perturb and observe method was most commonly preferred but it has various
drawbacks. In this method due to rapid change in the environmental conditions the misjudgment
phenomenon occurs due to which exact MPP is not achieved. This drawback can be overcome
using the incremental conductance which is mainly discussed in this paper.

2.4.1 Incremental conductance

Overcoming the drawbacks of P & O, this technique works at the maximum power point of the
solar panel. The disturbance given to the parameter such as voltage and current is small enough
to avoid the misjudgment phenomenon. It follows the algorithm to achieve the point of MPP by
calculating the slope of P-V characteristics. In this method the maximum power point is tracked
by the MPPT and once it is tracked it stops perturbing and starts working at maximum MPP.
This can be possible by calculating the relationships between dI/dV and – I/V. This relationship
can be derived by calculating the slope of PV characteristics as follows:-

dP d ( VI ) dI
= =I + V
dV dV dV

dP dI −I
At the MMP: dV =0 So dV = V ......(1)

so to achieve the MPP above condition of eq. (1) has to be satisfied. This is shown in the
algorithm of incremental conductance. The above relation can be shown in the below graph:-

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 Figure 11. Graph of solar output with MPPT
From the above graph it is observed that at dI/dV=-I/V the slope of graph is zero which is the
maximum power point (MPP) whereas it is increasing at the left of MPP and decreasing at the
right of MPP. Using this relationship between dI/dV and -I/V the algorithm is generated as
follows in figure 12.

Figure 12: Flow chart of incremental conductance algorithm

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In this algorithm first step is to set a reference value for the voltage and current at which the
MPP occurs. Now the output of solar or the load voltage and current are compared with the
reference to take action for the increase or decrease in duty cycle. Increase or decrease in the
voltage is achieved by the buck-boost dc-dc converter [5]. Comparison of the voltage is done by
voltage divider circuit and current by hall-effect sensor [7]. Through this the MPP point is
achieved and can be easily understood by the flowchart in fig 4 and fig 5 showing the I-V and P-
V characteristics.

The advantages of incremental conductance are:

 It has High steady state accuracy.

 Good tracking efficiency.
 Response is high.
 Adaptable to frequent changes in the environmental conditions.
 Increased time period of energy conversion in a day.
 Able to locate exact MPP.

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 CHAPTER 3

MATERIAL AND METHOD

3.1 Load Estimation and power consumption

3.1.1 Calculating Power Consumption

There was need to determine the size of the load that were powered. The unit of measurement
used was watt-Hour because it was applicable to both AC and DC circuits. The table below
shows the average daily watt hours, the highest AC load in watts, the total AC connected wattage
at a time and the total watt-hour per day. These had allowed for easy determination of how many
modules that were needed to produce the power required and how many batteries that were also
needed to store the power. The table below was an analysis of energy usage for a representative
of ATTC Photocopy house. The loads were itemized for its individual run time per day is
summed the watt hour of all the units for a total daily watt hour figure. The chart below helps for
clear understanding of where the power had gone to and it also gave an idea of how to reduce the
loads in the most effective manner when required.

To design the Solar PV system the following steps are taken into account. The steps are:

Step 1: Load estimation

Table 1: Load estimation

S.No Appliance Wattage No.# Total wattage No. of Energy=Total

. (W) =W*No.# (W) hours wattage * no. .
(hr) of hours (Whr)
1 Photocopy machine 1400 3 1400*3=4,200 8hr 4,200*8=33,600
2 Desktop Dell 250 1 250*1=250 8hr 250*8=2,000
3 Monitor 60 1 60*1=60 8hr 60*8=480
4 Florescent lamp 36 2 36*2=72 8hr 96*8=768
5 Florescent lamp pair 48 2 48*2=96 8hr 72*8=576
(twice)
6 Duplicating machine 1,000 1 1,000*1 8hr 1,000*8=8,000
Total wattage Total Energy=
=5,678 45,424

16
Step 2: Determining the size and choice of electronics components

The Electronic components include an Inverter (DC-AC converter ), DC-DC converter (for
higher or lower DC voltages) and MPPT/charge controllers (for optimal generation of
electricity). The determination of capacity of these components depends on the total voltage and
current of the loads. In the case of inverter, the capacity of inverter is given in terms of voltage *
current or VA. The capacity of the inverter depends on the total wattage of the load and inverter
efficiency. Inverter efficiency is output power capacity (watt) divided by input power capacity
(watt).

In house hold socket outlet has single phase AC supply with 220 V. Since AC with 220V is the
only electrical power we have though out the Ethiopia as a standard, electronic devices use 220V
AC. All our loads are 220V AC rated devices.

1) Inverter Selection
The inverter should be selected in such a way that it should supply the desired power to the load.
The total connected power of the load is equal to the desired output power of the inverter. In
practice, it is good to choose an inverter having a power capacity higher than the total connected
load. Estimation of required Input power to Inverter for a given connected load
Table 2: Inverter power

Load Inverter
Total wattage of the load(w) Efficiency Output(w) Input VA = Output*100÷efficiency
5,678 93 5,678 (5,678*100÷93) = 6,105VA

Estimation of required Input Energy to Inverter for a given Energy consumption of all loads
Table 3: Inverter energy

Total Energy (Whr) Efficiency Total energy(whr)

45,424 93 45,424 * 100 ÷ 93 = 48,843 whr

2) Solar charge controller selection

To prevent overcharging of a battery, a charge controller is used to sense when the batteries are
fully charged and to stop or reduce the amount of energy flowing from the energy source to the
batteries. The solar charge controller or MPPT should be chosen as per the required input and
output voltage and current of load and battery.

Table 4: Controller power rating

Energy(Whr) Wattage(w) Voltage(V) Max current(A)

48,843 6,105 48 127A

17
 3) Determining the battery size
In Selection of battery type, usually lead acid type batteries are chosen. In general lead acid
batteries are more-cost effective, because lead acid battery will not lose its performance when
periodic discharge are omitted crystals are not formed on the cell plates. Selection of battery
voltage depends on inverter and generation controller equipment generally available. They come
in specific voltages from 12, 24, 48 up to 120 and 240V DC and thus batteries must be selected
and combined in series to meet this voltage requirement. The number of battery strings that can
be connected in parallel is limited to about five without rigorous monitoring and higher
maintenance costs. This means that once the general battery bank capacity has been selected the
size of the individual battery type must be chosen accordingly. Batteries may be connected in
series to increase the battery bank voltage and in parallel to increase the capacity.

Battery sizing consists in calculating the number of batteries needed for a renewable energy
system. This mainly depends on the days of autonomy desired. Days of autonomy are the
number of days a battery system will supply a given load without being recharged by a PV array.
If the load being supplied is not critical then 2 to 3 autonomy days are commonly used. For
critical loads 5 days of autonomy are recommended. A critical load is a load that must be used all
the time. The battery’s capacity will decrease at lower temperatures and increase at higher
temperature. The battery’s life increases at lower temperature and decreases at higher. It is
recommended to keep the battery’s storage system at 25 ºC.

So we have the total load energy which is equal to 48,843 Wh and the system 48V. Ampere-hour
capacity of to be supplied is given by:

energy∈watt 48,843
Ah= = =1,018 Ah
system voltage∈ volt 48

Table 5: Battery size

Energy(Whr) System voltage(V) Ah capacity to be supplied

48,843 48 48,843÷48=1,018 Ah
Total ampere-hour capacity of battery is given by:

Ah of battery =input energy ¿ the inverter∗number days of autonomy ¿

DOD X system voltage

Where DOD is depth of discharge given 50%, number days of autonomy is 2

48,843 wh X 2
Ah of battery = =4,070 Ah
0.5 X 48

18
Table 6: Depth of Discharge

Actual Ah capacity after DOD No of days of autonomy Final required battery

(Ah) capacity (Ah)
2,035 2 2,035*2=4,070Ah
Total number of battery is obtained by dividing total ampere-hour capacity of battery by ampere-
hour capacity of one battery. In this study we took the ampere-hour of one battery as 250Ah.

4,070 Ah
Total number of battery = =16.28 ᴝ 17 pieces of battery
250 Ah
4) Determining the Solar PV Module size

The SPV module must supply enough energy to the battery, so that battery can supply enough
energy to the inverter, in order to supply enough energy to the load as per the need. The input
energy to be supplied at the input of inverter is 48,843 Wh. This energy is supplied by the
Battery bank.

A) Energy calculation

Table 7: Energy of SPV

Total Energy (wh) Battery Efficiency Energy from SPV (wh)

48,843 93% 48,843 ÷0.93=52,519 whr
B) Solar PV Module wattage estimation

Energy from SPV module NO. of sunshine hours (hr) Solar PV wattage(w)
(wh)
52,519 8.3 52,519÷8.3=6328 watts
Table 8 Power of SPV

6328 watts
No of solar PV array = =26
250 watts

The connection of all PV arrays will be in series ,since the voltage of the array is 30.3V at
optimal point of operation.

19
 5) Determine the size of wires (in mm), fuse (A), Junction box (V, A) sizing.
Fuses, wires, and junction boxes should be chosen for the maximum possible currents and
voltages that are likely to occur in the system. Mainly, the parameter used for choosing these
products is current. Normally, a standalone system will have DC side as well as AC side.
Therefore, we need to look at the maximum voltage and current for DC and AC sides.

Wire Sizing: The wire size is determined by the maximum expected current in the system and the
voltage drop. The current-carrying capacity of the wire should be at least 125% of the maximum
expected current to account for potential overloads. The voltage drop should be kept within the
acceptable limits, typically less than 3% for the entire system. The National Electrical Code
(NEC) provides tables that specify the minimum wire size based on the current and voltage.

Fuse Sizing: The fuse size should be selected to protect the wires from over-current conditions.
The fuse rating should be higher than the maximum expected current in the circuit, but not more
than 125% of the circuit’s continuous current. Fuses should be placed at the beginning of each
circuit to protect the entire circuit.

Junction Box Sizing: The junction box should be sized to accommodate the number and size of
the incoming and outgoing wires. The box should have enough space to allow for proper wire
bending and termination. The NEC provides guidelines for the minimum size of junction boxes
based on the number and size of the wires.

It’s important to note that these are just general guidelines, and the actual wire, fuse, and junction
box sizes may vary depending on the specific details of SPV system, such as the total system
capacity, the number and type of solar panels, the length of the wiring runs, and the local
electrical code requirements.

The equation below can be used to determine the cross section of copper wire.
pxLxIx 2
A=
Vd
Where:
• p=resistivity of wire ----- [For copper p=1.724 x 10-8 Ω ⋅m]
• L = length of wire (in m)
• A = cross sectional area of cable in mm2
• I =the rated current of regulator, amps
• Vd =Voltage drop, volts
In both AC and DC wiring, the voltage drop is taken not to exceed 4 % value.
4
Vd= V
100
The voltage V is typically,
a. Cable between PV modules and Batteries = 12V, 24 V or 48V
b. Cable between the Battery Bank and the Inverter = 12V, 24V or 48V.

20
 6) Mounting and Tilting the Solar Panel
After designing the solar system, buy all the components with appropriate rating as per the
previous steps. Now it is time to mount the solar panel. First choose a suitable location on the
roof top, or on the ground, where there is no obstruction of sunlight. Prepare the mounting stand:
You can make it by your own or buy one. Tilting: To get the most from solar panels, you need
to point them in the direction that captures the maximum. The optimal tilt and orientation will
depend on your location, energy needs, and other factors. Proper mounting and tilting will
maximize the solar panel's energy production.

3.2 Cost estimation

A summary of the costs of the individual system components and the total net present cost . It
can be seen that the PV plate , inverter and battery have the highest capital cost . But it has very
low running cost . Because it does not require maintenance regularly .total net present cost has a
birr equivalent of 798,500 birr.

Item Pcs. Power or Energy price Current total cost

PV module 26 6328 watts 1watt = 50 325,000 birr
(Mono-Crystalline 250W Solar birr
Panel)

Inverter 1 6,000 watts 48,500 birr 48,500 birr

(standard)
Battery 17 250Ahr /48 V 25,000 425,000 birr
Total 798,500 birr
table 9 cost estimation

21
 CHAPTER 4

SIMULATION OF PV POWER SYSTEMS

In this Section, renewable energy technology for generating electricity that suitable to MFM
ATTC printing house will be discussed. The load demand and the potential renewable energy
resource have been already known. The suitable renewable energy technologies that can be
applied to photovoltaic with storage Batteries. The schematic of the system can be seen in Figure

Figure 1 schematic diagram PV system with AC Load

4.1 MATLAB Modelling of PV system

The name MATLAB stands for MATrix LABoratory. MATLAB was written originally to
provide easy access to matrix software developed by the LINPACK (linear system package) and
EISPACK (Eigen system package) projects. MATLAB is a high-performance language for
technical computing. It integrates computation, visualization, and programming environment.
Furthermore, MATLAB is a modern programming language environment: it has sophisticated
data structures, contains built-in editing and debugging tools, and supports object-oriented
programming. These factors make MATLAB an excellent tool for teaching and research.
Simulink is a graphical extension to MATLAB for modeling and simulation of systems. In
Simulink, systems are drawn on screen as block diagrams. Many elements of block diagrams are
available, such as transfer functions, summing junctions, etc., as well as virtual input and output
devices such as function generators and oscilloscopes.

22
23
4.2 Simulation result

Figure 2: PV Array before Battery is connected

Figure 3: Out put form boost converter before load is connected

Figure 4: Out put of PV array after load is connected

24
Figure 5: Image form boost converter after load is connected

Figure 6: While battery is charging

Figure 7: output form inverter to load

25
 CHAPTER 5

CONCLUSION AND RECOMMENDATION

5.1 Conclusion

This paper presents the simulation of the PV system with Incremental conductance MPPT
algorithm has been successfully implemented in the Matlab/Simulink. This method computes the
maximum power and controls directly the extracted power from the PV cell. So that it forces the
PV module to operate at close to maximum power operation point to draw maximum available
power. The project was intended to supply 52,519 Whr of energy to the ATTC photocopy house.
From the above simulations we can see that using the incremental conductance technique the
MPP can be easily determined without much perturbations. Also the efficiency of overall system
is increased with reduction in cost. With this method the system responds quickly to any changes
in weather conditions. It continuously maintains the maximum power point and gives the
maximum power output. It has successfully increased the tracking hours of the solar panel. The
results of the output converter power shows that it is achieving the maximum extracting power
and it is constantly working near the maximum operating point of the PV Module. It is found that
a maximum power of 6328 watts is achieved.

5.2 Recommendation

In the system we have power electronics devices , which will produce harmonics and noise in the
system . In order to eliminate the harmonics it is better to use well designed filter .

Also we were using inverters to deliver power to the AC load . It is better to use DC load to in
order to use the power produced by the system minimizing the loss (i.e. a noise and harmonics.)

26
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[2] D. R. william christorper, “Comparative study of P&O and InC MPPT Algorithms,”
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[11] Liang-Rui Chen, Chih-Hui Tsai, Yuan-Li Lin, And Yen-Shin Lai, "A Biological Swarm
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