1. Miniscale Energy Generation Peter C. Gravelle, Borce Gorevski, Nick Ieva Sponsor/Advisor: Dr. S. Lyshevski, Electrical Engineering Department

2. The Team Left to Right: Nick Ieva, Peter C. Gravelle , Borce Gorevski Advisor/Sponsor: Dr. S Lyshevski

3. Objective • To design and prototype a self-sufficient mini-scale generator.

4. Rectifier (AC-DC) Store in supercapacitor Velocityof Water No Angular velocity of turbine Is voltage too high? DC-DC conversion (increase voltage) Velocity of magnets over windings Yes Zener diode burns excess energy Load Current in windings (AC) Block Diagram/Roadmap

5. Goals • Sub-20 cm3 volume • At least 0.1 W/cm3 • We want to exceed these • Turbine (Runner) with permanent magnets • Salt-water resistant (nautical/sharks) • Output voltage greater than 7V

6. Design Choices • Generator • Turbine • Magnets • Windings • Electronics • Energy storage • Energy harvesting circuitry • Housing

7. Turbine Pelton Turbine Francis Turbine

8. We Picked a Pelton-like wheel

9. Technical Details: Turbine • Diameter of turbine: <2.5cm • Material: plastic • Nylon (reinforced or not?) • Magnets mounted on wheel using water-proof epoxy.

10. Magnets • SmCo • Corrosion resistant • More expensive • Weaker • NdFeB • Very highly magnetic • Low cost • Very corrodible

11. Feasibility Chart: Magnets T1 3 2 1 E1 T2 NdFeB 0 SmCo T4 T3 Magnet Feasibility Graph

12. We’re using NdFeB • Dr. Lyshevski recommended it • Cheaper • Stronger • More easily machined into small parts • Small arcs required for our design • Corrosion can be dealt with by plastic coating • Right now looking at ring magnets with OD = 0.625”, ID = 0.250”, and thickness of either 0.250” or 0.375”

13. Field Simulation for N35 grade NdFeB (3mm dia, 1mm thick disc)

14. Windings • Winding wire will be supplied by Dr. Lyshevski • Axial motor winding pattern • Pattern will be made of plastic (see below)

15. Energy Storage • Batteries • High energy density • Limited charge cycles • Lower voltage • Temperature sensitivity • Supercapacitors • High (but lower than batteries) energy density • Unlimited charge cycles • Higher voltage • Temperature insensitive ( -40C to 70C)

16. Batteries vs. Supercapacitors

17. We picked Supercapacitors • Smaller size • Greater cycle life • Will not ignite in water • Greater power density • High voltage density

18. Feasibility for Supercapacitors

19. Feasibility for Super Capacitors

20. Energy Harvesting: AC-DC • Standard bridge rectifier • Takes AC input and turns it into DC output • We will be using a capacitor for additional smoothing

21. Harvesting Circuitry: Voltage Regulation • Switched-capacitor DC-DC voltage converter • Efficiency: 88-96% • Doubles input voltage • Max output current: 200mA • Step-up (boost) converter • Has an efficiency of 60-90% • But needs more parts (volume, cost) • Adjustable output voltage/current • More robust • Voltage/thermal/current protections • Max output current: 1A

23. Housing Design

24. House Design • This cylindrical casing was designed so we can save on volume

25. Housing Design Our final design has the codename: Windmill -please note the extended shaft The idea came from a meeting with Dr. Lyshevski

26. Questions and Comments