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THE UNIVERSITY OF THE WEST INDIES
FACULTY OF ENGINEERING
DEPARTMENT OF MECHANICAL AND MANUFACTURING ENGINEERING

NAME: Che’ Hudlin
ID #: 815117450
PROJECT TITLE: The Design, Model and Simulation of a Home Charging Station for an Electric Car in Trinidad and Tobago
FIRST EXAMINER: Dr. Anthony Adeyanju
SECOND EXAMINER: Mr. Sennen Matabadal
MODERATOR: Dr. Krishpersad Manohar
CHAPTER 1
INTRODUCTION
1.1. Rationale
In this Modern day and age, the most frequent use of land transportation worldwide is the use of vehicles that mainly utilize the combustion of Gasoline and Diesel (cite). These are both made up of fossil fuels which is widely known as a non-renewable source that takes a very long time to be formed. With the growing demand for fossil fuel, it is estimated that the world reserves may run out within the next century. In addition to fossil fuels being a rapidly depleting limited resource, it also causes major harm to the environment in the form of air pollution and carbon dioxide (CO2) emissions (cite).

Over the past few years, the residents of Trinidad and Tobago have sustained a significant increase in cost of living locally due to the reducing subsidy on oil and gas which has been attributed to the current state of the economy. Before, where it would have taken approximately 165 TTD to have a full tank of gas whereas the current amount is somewhere close to 300 TTD using super unleaded gas (cite). As such, people are beginning to seek ulterior motives of land transportation to reduce the dependency on oil and gas. In recent years, there has been an increase of hybrid vehicles on the road and as of recently, Hyundai IONIQ released its 2018 Fully Electric Car which has been on sale locally. With fully electric cars ruling the roads on the horizon a new market may soon come about, and this is Charging stations for these Electric Vehicles (cite).
Moving forward in the technological era has brought about the need to look into the adaptation of electric vehicles in our society of Trinidad and Tobago. This project will provide valuable information to any individual who is interested in attaining an electric car and also wishes to invest in a Renewable Home Charging Station for said vehicle. Acquiring this system may possess many benefits in terms of being healthier for the environment, being able to be sustained by a renewal resource such as solar energy, as well as the future cost benefits of never having to spend on gas again.
1.2. Problem Statement
1.3. Aim and Objectives
The purpose of this project is to Design, Model and Simulate a Solar Powered Electric Car Home Charging Station in Trinidad and Tobago. The following are the specific objectives of this project:
To Design and Simulate a Renewable Energy Home Charging Station for Electric Cars using MATLAB – Simulink.

To estimate the amount of Electrical Energy needed from solar panel(s) throughout a typically ‘normal’ One – Year Period in Trinidad and Tobago.

To determine how the Solar Charging station would perform if it was used as a part-time Home Energy Management System.
To generate a price of this Home Charging Station, as well as determine its feasibility and how much an average person should plan to save per annum by switching to an electric car and home charging system.

1.4. Scope of Project
This projects focuses on the following:
The Development of a renewable home charging station for electric cars by the conversion of sunlight to electricity via solar panels.

The amount of electrical energy gained from the system and its ability to not only conduct its primary objective (charging EV), but also other features such as charging devices and being used to operate home appliances.

The feasibility of the project with respect to the cost of building the system and how much this system saves its customers in years to come.
CHAPTER 2
LITERATURE REVIEW
2.1. The Electric Car Charging Station
Electric Vehicle (EV) charging stations are considered to be an essential component of owning an EV. Every (fully) Electric Vehicle does not possess a gas tank and a combustion engine but instead functions by using one or multiple electric motors (cite). These motors utilize electricity coming from the battery of the car– as opposed to replenishing one’s vehicle with gallons of gas, you just simply need to plug the EV into a charging station to energize your battery. There are multiple types of EV charging stations that have different characteristics, for example some installations may just require plugging it into a standard wall outlet while others would require professionals to install it successfully. Also, some EV charging stations may take longer to charge your vehicle depending on the type of charger you use. (According to )The EV Charging stations are usually separated in three (3) different categories which are described below:
Level 1 EV charging stations as shown in Figure 1 charge the battery using a 120 volt(V), alternating-current(AC) plug which is usually found in a standard household outlet. Level 1 charging usually requires between 8 to 12 hours to fully charge a battery depending on the battery technology used in the EV. This type of charging which usually occurs in the owner’s home is most commonly done overnight. Some well-known manufacturers of EV Level 1 chargers are Leviton, AeroVironment, Duosida and Orion.

Figure 1: A level 1 EV charger
Level 2 EV charging stations as shown in Figure 2 use a 240 volt(V), alternating-current(AC). Unlike the Level 1 chargers they require an experienced electrician to install because they cannot simply use a standard wall outlet. Level 2 EV charging usually takes between 4 to 6 hours to fully charge the battery depending on the battery technology used in the vehicle. This type of charging can be used in residential homes, places of employment as well as public areas (cite). Some well-known manufacturers of EV Level 2 chargers are Chargepoint and Siemens.

Figure 2: A level 2 EV charger
Level 3 EV charging stations as shown in Figure 3 are well-known around the world as being called DC fast charging stations. This is the fastest category of EV charging with it being able to recharge an EV battery between 20-35minutes using a 480 volt (V), direct-current (DC) plug (cite). This Level 3 EV charging station is mostly utilized in commercial and industrial applications due to the amount of electric energy that is needed by the specialized, high-powered equipment within the system. Even though this is the fastest way to recharge your EV Battery, not all fully electric vehicles can be charged using this method.

Figure 3: The characteristics of the different types EV chargers
For this project, the scope of focus will be on Level 2 charging stations since the aim is to design a Completely Renewable Solar Home charging station for electrical cars that would satisfy the needs of EV owners within Trinidad by having an output of between 200 – 240 volts (V).

2.1. Brief History on Electric Vehicle Charging Stations
The focus of this section is to discuss the evolution of EV charging stations over the past decades from the original set of electric vehicles being charged to modern day society. Obvious differences will be seen as to how EVs were charged back then compared to now. However, the question may be asked “How were electric vehicles able to function properly decades ago?” If one were to own an electric car in the 20th century, there were only really two (2) ways to charge it. The first option was to leave it with the dealer from whom the EV was purchased and he/she would keep it for the customer (fully charged) at their personal charging spot where the vehicle can be requested when needed (as displayed in Figure 4 below). The second (and most frequent) option (as displayed in Figure 5 below), would be to charge the car battery while it is intact or remove the battery and carry it to be charged in a “battery room”.

Figure 4: Charging of the 1st generation of electric cars

Figure 5: A Battery Room that was used an ulterior EV charging option
As time went on, advancements in technology revolutionized electric vehicles and how they were charged. During the late 1950s, interest in space travel assisted in developing superior batteries for electric vehicles making them faster and more capable of covering longer distances (cite). Forty years later, electric vehicles would make a promising return to the market due to the high demand as a result of the rise in oil prices and the effect exhaust emissions were having on the environment (cite). Within the late 1990s to early 2000s, GM MagneCharge introduced a home inductive charging station which was known as J1773 and this ruled the market of electric car charging until 2003 (cite). It was mainly used to charge the Toyota RAV4. The new charging station that made the J1773 obsolete after this phase is the SAE-J1772 (Revision 1) which were produced by the California Air Resources Board (CARB) (cite). This electric vehicle charging station delivered 6.6 kilowatts (kW) of electrical power and was then succeeded by the SAE-J1772 (Revision 2) in 2009. This upgraded version delivered 19.2 kilowatts (kW), 120-240 volts (V) alternating-current (AC) which was developed by Yazaki (cite). It did not take long before a new company called CHAdeMO released their DC fast charging station infrastructure in 2011, which delivered up to a staggering 65 kilowatts (kW) of electrical power with a 500 volts (V),125 ampere (A) direct-current (DC) (cite). Since then EV charging stations have evolved in ways such as using renewable energy EV charging stations from companies such as Envision Solar, an organization best known for their 2013 launch of the world’s first fully renewable car charger. Since then, advancements on improving charging stations and meeting modern day consumer demands has been a top priority for many companies. Some of these advancements include energy storage where new ways to store energy are produced by solar photovoltaic systems. Another notable improvement is Solar Cell technology, where the aim is to improve the efficiency of solar cells which are located in solar panels.
There is no doubt that EV charging stations have come a long way since the 20th century and will continue to rise as the need for an eco- friendly future becomes more pertinent. As the Republic of Trinidad and Tobago which is globally known for its oil and natural gases moves forward in its transition to a greener future, projects and studies based on renewable energy such as this one will help pave the way for a major change in transportation nationwide.
2.3. Photovoltaic (PV) Systems
A photovoltaic (PV) system can be simply described as a system that utilizes solar energy, that is, radiant energy that is emitted from the Sun to generate electric power. Despite the difference in equipment used in PV systems, they are similar to other electrical systems with respect to the interfacing as well as principles of operation (cite). The PV system process begins with the solar cells that are located on solar panel modules. As light shines on the cells an electric field is created over separate layers that causes direct current (DC) electricity to flow (cite). This DC current can either be used to directly charge batteries and devices such as cellphones or it could be directed through an inverter that will convert the direct current (DC) to alternating current (AC). This current is used for household appliances such as refrigerators and light bulbs. This project utilizes the same principles as a PV system to charge an electric car battery instead of home appliances.

Figure 6: A Photovoltaic System
2.4. Home Energy Management Systems
CHAPTER 3
METHODOLOGY
The development phase of this project are as follows:
294132020129500
Figure 6: The Development Process of this Project
3.1. Black box
1478280270510Primary Function:
– convert solar energy to electricity
– convert wind energy to electricity
400000Primary Function:
– convert solar energy to electricity
– convert wind energy to electricity
4251960392430Charge Electric Car
00Charge Electric Car
INPUTS BLACK BOX OUTPUT
378714087630008153403429000Wind Energy
378714027559000428244062230Run household appliances: e.g. Lightbulbs and oscillating fans
00Run household appliances: e.g. Lightbulbs and oscillating fans
8382003175000Solar Energy
4312920318135Charge electronic devices: e.g. Cellular Phones and tablets
00Charge electronic devices: e.g. Cellular Phones and tablets

381000016319500
4343400260985Losses: e.g. heat
00Losses: e.g. heat
376428034353500
3.2. CONCEPTUAL SELECTION
Concept 1: Wind Powered Electric Vehicle Home Charging Station
This design utilizes wind energy to turn the blades of the turbine. The rotational energy of the spinning blades must first past through a gear box to achieve a high speed ratio and is then sent to the generator to produce an electrical current. The alternating current (AC) then passes through a single phase step-up transformer. As the alternating current (AC) leaves the wind turbine, it passes through a full wave rectifier to convert the alternating current (DC) to direct current (DC). The current then flows through a DC to DC converter before it is carried to the Lead acid Battery to charge. As the current leaves the battery it passes through a power inverter which converts it DC back to AC and amplifies the current before it is plugged in to the electric car. Although the wind turbine can produce energy anytime of the day, production will be too expensive and would not produce enough energy if the house is in an undesirable location such as the bottom of a hill.

Figure 7: Design of a Wind Electric Vehicle Charging Station
Concept 2: Solar Powered Electric Vehicle Home Charging Station
The second design shown is a solar EV charging station. Solar panels are used to convert light energy gained from the sun to electrical DC current. The current is then carried through a Buck-Boost converter that could step-up or step-down DC voltage in a fluent manner to achieve the required voltage. Before the DC charges the battery it must first pass through a Maximum Power Point Tracking (MPPT) controller. This is done to regulate and control the power coming from the solar panels to the batteries which helps prolong the health of the batteries. The output of the battery is then sent into two (2) directions:
To a buck converter where the voltage can be stepped down to allow devices such as tablets and cellular phones to be charged via a USB port.

Towards a power inverter where the DC from the battery is converted back to AC and Amplified.

The AC leaving the power inverter is then used to either charge the Electric Vehicle (primary objective) or can flow through a step-down transformer so household appliances (e.g. microwave and toaster) can be used (secondary objective).

Figure 8: Design of a Solar Powered Electric Vehicle Home Charging Station
Concept 3: Hybrid Electric Vehicle Home Charging Station
This design is a combination of the previous two (2) concepts which utilizes both solar and wind energy to create an electrical current. The current coming from the wind turbine (after it has been converted to DC) is added to the DC coming from the solar panel, the resultant current is then used to charge the battery. The output of the battery then passes through a power inverter, here it is converted back to AC and is amplified before going to charge the Electric Car. Although this charging station would produce the most electrical energy out of all the concepts (depending on ideal location and size of wind turbine), the cost and installation will be too complicated and expensive to be used for a home charging station.

Figure 8: Design of a Hybrid Electric Vehicle Home Charging Station
Concept 2: Solar Powered Electric Vehicle Home Charging Station will be selected for this project. With Trinidad and Tobago being located tropical twin island that is located in the Caribbean, solar energy would be the best choice of renewable energy for this home charging station. This concept also allows for the electrical energy produced by this home charging station to be utilized for charging electronic devices and usage of some household appliances at least for a portion of the day.

3.3. EVALUATION OF CONCEPTUAL DESIGNS
The design to be selected is based on the following attributes:
Cost
Energy Production
Additional Features
Durability
Ease of Installation
Ease of Manufacture
Multiple design alternatives were analyzed using the Pairwise Comparison Chart and Selection matrix before the final design concept was chosen. Table 1 and Table 2 below shows how the different designs were weighed based on their attributes, this helped to identify the most suitable Renewable Home Charging Station design.

RATING / WEIGHTING METHOD
Table 1: Relative Weighting of Conceptual Designs using Selection Matrix
ATTRIBUTES
Ease of Manufacture Ease of
Installation Cost
Durability
AdditionalFeatures Energy
Production x 2x +1 Relative
Weighting
COST 1 1 – 1 1 0 4 9 0.236
ENERGY PRODUCTION 1 1 1 1 1 – 5 11 0.289
ADDITIONAL FEATURES 0 1 0 1 – 0 2 5 0.132
DURABILITY 1 1 0 – 1 0 3 7 0.184
EASE OF MANUFACTURE – 0 0 0 1 0 1 3 0.079
EASE OF INSTALLATION 1 – 0 0 0 0 1 3 0.079
TOTAL – – 38 1
RATING / WEIGHTING METHOD
Table 2: Final Rating of Conceptual Designs using a Pairwise Comparison Chart
ATTRIBUTES RELATIVE RATING Weight factor x Relative weighting
WEIGHTING ALT #1 ALT #2 ALT #3 ALT #1 ALT #2 ALT #3
COST 0.236 4 5 3 0.944 1.18 0.708
ENERGYPRODUCTION 0.289 4 3 5 1.156 0.867 1.445
ADDITIONAL FEATURES 0.132 2 5 3 0.264 0.66 0.396
DURABILITY 0.184 5 5 5 0.92 0.92 0.92
EASE OF MANUFACTURE 0.079 4 3 3 0.316 0.237 0.237
EASE OF INSTALLATION 0.079 5 3 4 0.395 0.237 0.316
TOTAL 3.995 4.101 4.022
This rating is based on a scale of 1-5 where one indicates the least important attribute and five represents the most important attribute. From the rating table above, it shows that Alternative Design # 2 is the best design option for the development of the Renewable Home Charging Station.

3.4. MATLAB – SIMULINK
Simulink, an additional item to MALAB, gives an intuitive, graphical setting for modeling, simulating and examining dynamic systems such as a solar powered EV home charging station. This programme gives a Graphical User Interface (GUI), giving it the capability of developing a virtual model of the project design and making it possible to investigate the concepts of the Solar Powered Electric Vehicle Home Charging Station in detail.

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