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Fall 2006 ECE 445 Senior Design Project. Kinetic Power Mobile Energy Charger. About Us. Group 13 Professor : John Makela TA : Alex Spektor Group Members: Kai Yeen, Wong Leon Yeow, Ting Ming Hoong, Chong. Introduction. To meet the need of today’s mobile technology
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Fall 2006ECE 445 Senior Design Project Kinetic Power Mobile Energy Charger
About Us Group 13 Professor : John Makela TA : Alex Spektor Group Members: Kai Yeen, Wong Leon Yeow, Ting Ming Hoong, Chong
Introduction • To meet the need of today’s mobile technology • Mainly for military or rural uses where dedicated power supply is not available • Encompasses all members’ electrical and electronic skills with a mechanical component challenge
Objectives • Mobility • Energy Harvesting • No need external power supply • Environmental friendly
Revisions • Step Up Transformer removed • to increase current outflow • adequate generator voltage output • size of transformer • Voltage Regulator Circuit removed • Zener diode removed because of clamping • increase power efficiency to output
Revisions (continued..) • Triple generator configuration introduced • increase signal generation frequency • Filter capacitor removed • Reduces charging efficiency • Clamping effects • Current regulator introduced • To prevent backflow of current from Li-ion battery to any other generators
Device Part for battery Rectifier & Diode Main Generators Wrist Generators
Physics • Electromagnetic Induction by magnet moving in coil • Faraday’s Law: emf = -NdΦ/dt where N = number of coils Φ = magnetic flux t = time • Ohm’s law: V = IR where V = emf I = current R = resistance of coils • So a compromise must be reached for optimal device performance
Generator Design and Evolution First Generation Generator Second Generation & Dual-core Generator
Generator Cross-section… Coils Rod Magnet Flat magnets
Parameters of the Generators Note: All the generators are constructed using 28 AWG Copper Wire
Testing 4 main tests: • Generator Output • Circuit performance • Device performance • Field test
Generator Output • Generator is heart of device • Need output of 5V and 0.1A to accommodate lost throughout circuit and maintain higher voltage than battery • Range of output measured for open circuit and closed circuit voltage
Testing of Generator 1st Generation 2nd Generation (Dualcore) V = 23.0V spike V = 3.531V spike
Before Final Testing of Generator Output Final Design Output = 5.94V Output = 10.5V
Current Output 20 Ohms 2 ohms I = 0.391/ 2= 0.1955A I = 0.1095A
Open Circuit Voltage Frequency: 4.167 Hz
Circuit Performance • Mainly rectifier circuit tested Half Wave rectification Full Wave Rectification Device Rectification is confirmed 1 is output and 2 is input
Device Performance • Power output of generator tested P = V2/R • Power lost across circuit tested P = VI • Power collected at battery P = VIh
Calculations Generator Power • V = 5.11V • R = 25 Ohm • P = 1.044W Power Loss • V = 1V • I = 0.1A • P = 0.1W Efficiency Efficiency = 90.9%
Tests in improving efficiency • Switch to thicker wires. X • Add capacitor to reduce reactance. X • Add capacitor to reduce ripple. X • Find Schottky diode with smaller Vf. X
Field Test Summary • Low Battery Voltage to make a call: ~3.4 V • Critical Voltage (dead): ~3.0 V • Shorter time to charge when Li-ion battery at lower voltage level. • Longer time to charge when battery exceed ~3.3V
Ethical Concerns • Voltage Spike - Through rigorous testing, managed to limit the output of generator. -physical limitations do not allow the voltage to exceed acceptable voltage range • Current Spikes - With limitation of voltage current is also limited - Choice of coil material and gauge also limits current output • Uses - Peaceful use for generating power - Does not use fossil fuels
Cost Analysis • Labor: ($35/hr)*120hrs*3Engineers*2.5 = $ 31500 • Parts:
Extra Features • Silencer - For military purposes, generator silenced • Size - compact design, 6in x 5in • Weight - Lightweight (2.3lbs)
Special Thanks to… • Prof. P Krein • Prof. P Sauer • Prof. J Kimball • Prof. Makela • Alex Spektor … for their advice • Everyone in the Part Shop • Scott McDonald from the Machine Shop
Conclusion • Project conformed to all that we expected to achieve in the Design Review • Project was a success
Q & A • Any Questions?