1. Conceptual Design Presentation
Electric Bike: ECE Group 6

2. Presentation Overview
Introduction
Charging Method 1: Wireless Charging System
Wireless Charging System Proof of Concept Test
Charging Method 2: Physical Connection Charging System
Locking Methods
Conclusion

3. Introduction
Justin Hatcher

4. Sponsor Overview Project Sponsor – Efficient Systems LLC.
About Efficient Systems, LLC:
Tallahassee start-up company
Developing an electric bike sharing program
Focused on reducing carbon footprint
Focused on reducing traffic congestion

5. Electric Bike Overview
Electric bicycles are bicycles with an integrated electric motor
The motor can be engaged manually through use of a throttle controller
This allows the rider to travel quickly and comfortably
E-Bikes sharing programs are gaining popularity around the world
As of 2010:
120 million E-Bikes were reported in China
700,000 new E-bikes were sold in Europe

6. Problem Statement
To create a docking station capable of charging and securing E-Bike’s that requires minimal user interaction
Major Challenges:
How to charge the E-Bike’s?
How to securely lock the E-Bike’s?
How to minimize user interaction with the docking station?

7. Project Overview Project Current State: Major Project Goals:
Inconvenient docking method
Inconvenient charging method
Major Project Goals:
Develop a charging method that requires minimal user interface
Develop a locking method that requires minimal user interface
Incorporate the developed methods created into the docking station

8. Needs Analysis The E-Bike docking station should:
Be able to efficiently charge an E-Bike within 4 hours
Be able to securely lock an E-Bike using a mechanical lock
Utilize a front facing docking method
Require minimal user interaction
Be able to operate in adverse weather
Be modular and aesthetically pleasing
Be cost-effective

9. Project Design Approach

10. Charging Method 1
Hassan Aftab

11. Charging Method 1: Resonant Inductive Coupling
Midrange wireless transmission of electrical energy
Uses two self-resonant coils with internal capacitance
The magnetically coupled coils are set to resonate at same frequency
Allows for further transfer of power versus standard inductive coupling
Distances of up to 10 times the diameter of inductive coils
Study done by MIT allowed for self-resonant coils to transfer 60 W at 10 MHz over 2 meters at 40% efficiency

12. Charging Method 1: Resonant Inductive Coupling

13. Charging Method 1: Design Flow Chart

14. Charging Method 1
AC power drawn in from main electrical line ( V, Hz, 140 W) rectified to DC
Voltage-controlled oscillator used as an electronic oscillator to produce a periodic, oscillating signal
Frequency amplifier to adjust signal frequency so that it matches the resonant frequency of the sender and receiver inductive coils
Sender coil directly connected to the circuit within the station, receiver coil mounted on electric bike

15. Charging Method 1
Both coils are magnetically coupled and tuned to resonate at the same frequency
Power transfer will occur between the two coils within a near field
AC power taken from receiver coil will be rectified to DC
DC power will be used to charge lithium-ion battery mounted on the E-Bike
Directly connected to lithium-ion battery via a male 3 pin XLR connector

16. Charging Method 1 Advantages: Disadvantages:
Requires no user interaction
Weather resistant
Minimal risk to damage power transfer connections
Disadvantages:
More complex design
More expensive design
Lower power transfer efficiency compared to Charging Method 2
Potentially could causes higher energy costs and slower charging

17. Charging Method 1: Proof of Concept Test
Xiaorui Liu

18. Charging Method 1: Proof of Concept Test Diagram

19. Charging Method 1: Proof of Concept Test Results
Resonant plates fundamental frequency: 135 MHz – 145 MHz
When resonant plates were ideally coupled a Port 1-2 transfer of dB was achieved
Conversion Formula: 𝑑𝐵=10 log⁡( 𝑃 𝑟𝑒𝑐𝑖𝑒𝑣𝑒𝑑 𝑃 𝑡𝑟𝑎𝑛𝑠𝑓𝑒𝑟𝑒𝑑 )
Power received over power transferred is equivalent to the percentage of power that was transferred from Port 1 to Port 2
-2.91 dB is equivalent to a 51.17% power transfer

20. Charging Method 1: Proof of Concept Test Improvements
Areas to be improved:
Increase the efficiency and effectiveness of the induction coils
Increase the efficiency and effectiveness of the resonant plates
Reduce the fundamental frequency of the resonant plates
Expected results when improvements are made:
Increase in power transfer efficiency well above 50%
Significantly increase the distance between the resonant plates at which power can be efficiently transferred

21. Charging Method 1: Research
There is a push to have an international standard for wireless power transfer applications that transfer over 5 W of power
This comes in part from the automotive industry
The push is for the frequency of wireless power transfer to be 85 kHz
Evatran LLC has created an induction based wireless power transfer application for the Nissan Leaf and Chevy Volt
The system is capable of charging the Nissan Leaf in 8 hours and the Chevy Volt in 3 hours
The system supplies 7.68 kW of power at 240 V and 32 A

22. Charging Method 2
Gabriel Sejas

23. Charging Method 2: Physical Connection Flow Chart

24. Charging Method 2: Design Plans

25. Charging Method 2 Advantages: Disadvantages: Efficient charging system
Requires no user interaction
Simple and effective design
Potentially more reliable than Charging Method 1
Cost effective
Disadvantages:
Potentially easier to damage plug connections
Potentially less weather resistant than Charging Method 1
Potentially more difficult to design a mechanical locking system with charging functionality included
Mechanical locking system will need to position the E-Bike precisely in order to achieve ideal coupling

26. Locking Method Overview
Elijah Goodson, Hunter Harrison

27. Locking Mechanism Needs
Front end loaded locking mechanism
Autonomous
Weather and corrosion resistant
Relatively inexpensive
Relatively lightweight
Modular design

28. Bracket Design
With proper material selection the current designs will be cost effective
The design easily modifiable to be placed on future iterations of the bicycle
Can incorporate either charging method inductance or charging cord, however different bracket shape will be necessary

29. Bracket Design: Option 1

30. Bracket Design: Option 2

31. Station Design

32. Material Selection: Aluminum 2024-T3
Strength
High strength to weight ratio
Machinability
Ductile metal
Does not require special machinery to fabricate
Element
Content Wt. %
Aluminum, Al %
Chromium, Cr
0.1 % Max
Copper, Cu
3.8 – 4.9 %
Iron, Fe
0.5 % Max
Magnesium, Mg
1.2 – 1.8 %
Manganese, Mn
0.3 – 0.9 %
Silicon, Si
Titanium, Ti
0.15 % Max
Zinc, Zn
0.25 % Max

33. Material Selection: Aluminum 2024-T3
Cost
Low cost ($0.71 per pound as of October 14)
Life
Relatively corrosion resistant
Can be made virtually corrosion free
Priming and painting
Anodizing

34. Conclusion
Justin Hatcher

35. Decision Matrix Categories Transfer Efficiency Design Simplicity
Cost Efficiency
Tolerance Level
Totals
Values 10 6 8 7 #
Charging Method 1 50 24 87
Charging Method 2 90 48 64
209
Wireless Bracket 70 30 72 14
186
Plug Bracket 35
219
Clamp Claw 80 42 40
204
Deadbolt 56
244

36. Docking Station Design Research Docking Station Prototype Construction
Project Timeline
Today
Week 1 2 3 4 5 6 7
Finalize Docking Station Design
10/30/2015
Midterm Report
Complete Research and Development on Docking Station
11/13/2015
Purchase Materials for Docking Station
11/20/2015
Final Webpage Design
11/24/2015
Final Report
12/1/2015
Begin Prototype Construction
Midterm Presentation 2
11/19/2015
Poster Presentation
10/22/2015
Docking Station Design Research
Docking Station Materials Research
Docking Station Prototype Construction

37. Questions?