CHAPTER 3 METHODOLOGY The development phase of this project are as follows: 2941320201295 Figure 6: The Development Process of this Project3.1. Black box 1478280270510Primary Function:- convert solar energy to electricity- convert wind energy to electricity400000Primary Function:- convert solar energy to electricity- convert wind energy to electricity4251960392430Charge Electric Car00Charge Electric CarINPUTS BLACK BOX OUTPUT378714087630008153403429100Wind Energy378714027559000428244062230Run household appliances: e.g.
Lightbulbs and oscillating fans00Run household appliances: e.g. Lightbulbs and oscillating fans8382003175000Solar Energy 4312920318135Charge electronic devices: e.g. Cellular Phones and tablets00Charge electronic devices: e.g.
Cellular Phones and tablets3810000163195004343400260985Losses: e.g. heat00Losses: e.g. heat3764280343535003.
2. CONCEPTUAL SELECTION Concept 1: Wind Powered Electric Vehicle Home Charging StationThis 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 StationThe 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 StationConcept 3: Hybrid Electric Vehicle Home Charging StationThis 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 StationConcept 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 DESIGNSThe design to be selected is based on the following attributes: CostEnergy ProductionAdditional FeaturesDurabilityEase of InstallationEase of ManufactureMultiple 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 MatrixATTRIBUTESEase of Manufacture Ease ofInstallation CostDurability AdditionalFeatures Energy Production x 2x +1 RelativeWeighting COST 1 1 – 1 1 0 4 9 0.236ENERGY PRODUCTION 1 1 1 1 1 – 5 11 0.289ADDITIONAL FEATURES 0 1 0 1 – 0 2 5 0.132DURABILITY 1 1 0 – 1 0 3 7 0.
184EASE OF MANUFACTURE – 0 0 0 1 0 1 3 0.079EASE OF INSTALLATION 1 – 0 0 0 0 1 3 0.079TOTAL – – 38 1RATING / WEIGHTING METHOD Table 2: Final Rating of Conceptual Designs using a Pairwise Comparison ChartATTRIBUTES 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.