SOLAR CHARGER

Roya Sabri, Marcos López, Aniela Chertavian, Robert López, Octavio Viramontes, and Amanda Alvarado

PURPOSE

-To learn about solar cells -Develop a way to transfer solar energy to charge up a battery-Promote better understanding of alternative energy

SYSTEM ARCHITECTURE

Solar Cell

Inductor Diode

BatteryCapacitor

MOSFET

PWM

Triangle Wave

Generator

COMPONENT #5 SOLAR CELL

- Converts light energy into electricity- Power source for the charger

COMPONENT #1 BOOST CONVERTER-Steps up voltage from low to high value

INGREDIENTS!Capacitor: Two parallel plates storing electric charge Inductor: A coil of wire enclosing magnetic fluxSwitch: On/Off- can be implemented using a FETDiode: Allows the flow of current in only one direction

COMPONENT #3 INDUCTOR AND CAPACITOR

-Inductor- stores energy in a magnetic field created by the electric current passing through it.-Capacitor- pair of conductors separated by a dielectric

(insulator). -When there is a difference across the conductors,

energy is stored and a electrical force between the conductors is formed.

COMPONENT #2 MOSFET SWITCH-Transistor that is a three terminal device… SOURCE, GATE, DRAIN. -Supplies the circuit with power-Functions like a switch

COMPONENT #4 DIODE-Allows flow of current in only one direction - Faucet analogy

COMPONENT #6 OP AMP (OPERATION AMPLIFIER)

- DC-coupled voltage amplifier with a differential input and a single-ended

output.

COMPONENT #7 TRIANGLE WAVE GENERATOR

- Generates pulses of energy which are created by an amplification of the difference between positive and negative input values from the OP AMP.

COMPONENT #8 PULSE WIDTH MODULATOR (PWM)

- Provides intermediate amounts of electric power between off and on. A switch provides full power when it is on and zero output when it is off.

Volt

ag

e

Time

Curr

en

t

Voltage

Knee Point – 3.6 Volts

KNEE POINT

COMPONENT #9 (EXTRA)ZENER DIODE & INTEGRATOR

-Functions like a normal diode, but use is different.- Once current is passed in the opposite direction, the diode will fail, and keep the breakdown voltage constant.-The breakdown voltage can then be utilized in feedback control.

Zener Diode + Integrator

LET’S PUT IT ALL TOGETHER

ACKNOWLEDGEMENTS

Very, very special thank you to Shriram Shivaraman and

Alyosha Molnar. We couldn’t have completed our project

without you two!

REFERENCES

Brain, M. (n.d.). HowStuffWorks "How Inductors Work". HowStuffWorks - Learn How Everything Works!. Retrieved July 23, 2010, from http://www.howstuffworks.com/

“Simple MOSFET switch design”. Electronic Circuits Projects Diagrams Free. Retrieved July 23, 2010, from http://www.electro-tech-online.com/general-electronics-chat/12910-simple-mosfet-switch-design.html

Op Amp Triangle-Wave Generator. (n.d.). eCircuit Center. Retrieved July 24, 2010, from http://www.ecircuitcenter.com/Circuits/op_tri_gen/op_tri_gen.htm