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SOUTH AFRICA POWER GENERATION

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GROUP MEMBERS Genesh Chen-Shue EE Aldo Puente EE & CpE Steven Bularca CS & CpE Armel Nidjeu EE

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Great need of electricity in the small South African community of the Pomolong Township, which is occupied by the less fortunate people of South Africa due to the aftereffects of apartheid. They are cut off from the rest of the world because they do not have electricity that will enable them to use electronic devices such computers, cell phones, and TVs. Even if they could afford the cost of power, the township is not close to the power grid. MOTIVATION

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Some of the sources that were considered were wind, hydro, solar, and mechanical/kinetic energy. The absolute most important objective is safety, because ensuring that the system is safe protects lives and mitigates damages. A major objective of this project is for the power generating system to be extremely efficient, because the resources are scarce and utilizing every bit of energy gives the townspeople more time to enjoy the electricity. Keeping in mind the technology aptitude of the users, ease of use became an unavoidable objective. One of the objectives is to successfully capture as much sunlight energy as possible. This will be done through a MPPT charge controller system. Deep cycle batteries are what are planned to be implemented for the project, because deep cycle batteries are made to be completely drained. The inverter will take the power from the charged batteries in the form of a DC input. desired. A robust, weather resistant, and safe enclosure to keep the entire system secure is a crucial part of the project. GOALS AND OBJECTIVES

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Spec. #Specification 1Ability to capture 6 hour of solar energy by our 500 W solar panel system. Solar panels will be two 300 W solar panel each which will be mounted on the roof of the community center of township. 2Must be able to power up to 500 W electronics for a period of 4 hours daily. 3Must be robust, weatherproof, safe, long lasting, and easy to maintain. 4There must be a gauge to measure battery charge. 5Inverter must able to support an input of 12V and output 220V at ~50 Hz 6Batteries must last at least 4 years. They will be placed in parallel making a 12V unit. Each battery will be 12V. 7Charge controller must implement MPPT for the solar energy capture. PROJECT SPECIFICATIONS

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BLOCK DIAGRAM

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We chose to use renewable energy over fossil or nuclear energy because the latter resources were not obtainable The renewable energy we chose to use was solar because it was scalable and could produce the most power given the limitation of funding. Power for solar panels cost around 1-2 dollars per Watt. For example, 2 305W Helios PV panels cost $752, making the cost per watt for that particular panel $1.23 per Watt. South Africa Irradiation levels are high The other renewable energy source that was considered was wind, but based on research, the cost for a wind turbine that would generate enough power was out of our budget range ENERGY

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Semiconductor MaterialPower Conversion Efficiency [%]Technology Mono-crystalline silicon20-24Crystalline Poly-crystalline silicon13-18Thick and Thin-film Gallium-arsenide20-29Crystalline Amorphous silicon8-13Thin-film Cadmium telluride10-17Thin-film Cadmium indium selenide 10-19Thin-film TYPES OF SOLAR PANELS

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BrandModelWattsCostHeightLengthCost PPCost PW Helios6T-250250$697.651,680 mm990 mm$348.25 $1.39 ReneSolaVirtus250$431.921,640 mm992 mm$215.96 $0.86 SunivaOPT250-60-4-1B0250$775.751,653 mm982 mm$387.88$1.16 MONOCRYSTALLINE PANEL CHOSEN

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CHOSEN SOLAR PANEL AND FRAME

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CHARGE CONTROLLER

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CHARGE CONTROLLER CONSIDERED CIRCUITS 555 TimerTI- BQ24650 TI- SM72442 NXP MPT612 Input Volt. Range 2-15 V5-28 V4.75-5.25 V1.8 V Max. Operating Temp. 70 C125 C105 C150 C Price$0.75$5.18$8.89$7.98

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SOLAR PANEL VOLTAGE SENSOR CIRCUIT

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SOLAR PANEL CURRENT SENSOR CIRCUIT

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MPT612

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BUCK-BOOST CONVERTER

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POWER SUPPLY

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JTAG/UART ADD ON BOARD

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THE DC/AC INVERTER

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INVERTER CONSIDERED CIRCUITS 555 TimerMSP430F2013QRSATEP Input Volt. Range 2-15 V1.8-3.6 Max. Operating Temp. 70 C125C Price$0.75$2.93

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SIGNAL GENERATION

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P-channel devices have a higher on resistance so there is greater power loss N-channel device will require a driver with a bootstrap capacitor to generate the higher voltage above the switching voltage of 230V to turn on the device P-ChannelN-Channel H-BRIDGE We decided to use IRFP260N-Channel MOSFETs, because efficiency was a stronger factor than convenience.

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OUTPUT FILTER System is filtered by an RC Low Pass Filter with: A 200V 1800uf electrolytic capacitor A Metalized Polypropylene Film Capacitor.

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INVERTER OUTPUT

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INVERTER PCB We used Eagle for the PCB Design and Ordered the PCB from Hackvana.com

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FloodedGelAGM ModelHRL12280WFRUB-24UB-GC2, 6V 225 Ah Cost$240$325$232 Performance88% charge/discharge efficiency 90% charge/discharge efficiency 98% charge/discharge efficiency SafetyHazardous Non-hazardous Size6V, 12V,24V AvailabilityEasy to find Internationally Hard to Find Internationally MaintenanceAdd waterNo Maintenance needed TYPES OF DEEP CYCLE BATTERIES

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BATTERY CONSIDERATIONS We had to calculate the amount of charge capacity the batteries should hold so we use Peukerts Law: t=H(C/IH)^k Peukert's Law expresses the capacity of a battery in terms of discharge rate, where t is the total time to discharge the battery, k is the Peukert constant, I is the discharge current, C is the rated capacity at the discharge rate, and H is the rated discharge time. We Calculated the proper Ah parameter to be around 75Ah. Considering the different battery types, we decided on flooded batteries because of the vast amounts available in the world. If the batteries needed to be replaced, we wanted the option that is the easiest to replace while maintaining a low cost.

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BATTERIES

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ENCASING

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CABLE WIRE USE 2 WIREPV wire RHH or RHWUL 4703 Used for grounded system Used for both undergrounded and grounded system Rated at 600 vRated at up to 2000 v Maximum operating temperature is 90C Maximum operating temperature150C Conductor: copper, aluminum, copper glad- aluminum Conductor: copper Stranded or solid conductor Stranded copper or tinned copper Price.50/ft.58/ft

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LOAD

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NameCharge Controller Solar PanelsInverterBatteriesOther StevenXXXXXXXXXX GeneshXXXXXXXXXX AldoXXXXXXXXXXXX ArmelXXXXXXXXXXXX WORK DISTRIBUTION

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PartVendorQuantityPrice ($) 250 Watt Solar Panel 72 Mono Crystalline Cells 36 Volt 76T250 Helios2700.00 12V 75Ah 280W BatteriesCSB3400.00 Charge Controller based on MPT612N/A (Designed)1300.00 Modified Sine Wave InverterN/A (Designed)1100.00 Chassis and WeatherproofingN/A (Designed)1200.00 Miscellaneous Electronic Components and WiresN/A 295.00 Total1995.00 BUDGET

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Charge Controller Finding an Inductor that can handle the current Buck-Boost converter Inverter Boost Converter Isolation of power lines from control line Other Issues Ventilation of Batteries Sponsors ISSUES

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Questions?