Wireless charging uses electromagnetic induction to transfer power from a transmitting source to a receiving device for battery charging without physical connection. It was first proposed in 1890 by Nikola Tesla and has since seen developments that enabled wireless powering of lightbulbs in 2007 and laptops in 2014. A survey of HKBU year 1 students found that most knew about wireless charging but not its working principles, and they accept the technology as convenient while noting slower speeds than wired charging. Applications include phones, watches, vehicles, and public infrastructure like electronically charged highways. While advantageous for its protected connections and convenience, disadvantages include slower charging rates and increased device complexity and cost. Wireless charging is seen as a promising technology that continues to develop for use

1. Wireless Charging
WANG Boxuan & ZHA Bohao & LIU Xinye
27 October 2017

2. Introduction
of
wireless
charging
Working
principle
Survey
Results
Applications
and
evaluations
Conclusion

3. What is wireless charging?
Wireless charging (also known as inductive charging) uses electromagnetic
fields to safely transfer power from a transmitting source to a receiving device
for the purposes of charging or recharging a battery wirelessly.
As the name suggests, it does so without the use of a physical connection.

4. Development of wireless charging
1890
Nikola·Tesla put
forward a
hypothesis
2007
MIT successfully
supplied power for
a bulb 2.7 meters
away
2014
DELL declared that
they can apply
wireless charging
to laptop

5. How does it work?
● Physical principle
Induction chargers use an induction coil to create an alternating
electromagnetic field from within a charging base, and a second induction coil
in the portable device takes power from the electromagnetic field and
converts it back into electric current to charge the battery. The two induction
coils in proximity combine to form an electrical transformer.

6. How does it work? (5 key steps)
Mains voltage is converted into high
frequency alternating current (AC).
The alternating current (AC) is sent to the
transmitter coil by the transmitter
circuit. The AC then induces a time varying
magnetic field in the transmitter coil.
AC flowing within the transmitter coil
induces a magnetic field which extends to
the receiver coil (when within a specified
distance).
The magnetic field generates current within
the receiver coil of the device.
Current flowing within the receiver coil is
converted into direct current (DC) by the
receiver circuit, which can then be used to
wirelessly charge the battery.

7. Online Survey
Target: Year 1 Students in HKBU
Information: understanding of wireless charging
Website:
https://docs.google.com/forms/d/e/1FAIpQLSe75yXQWXsPITEEbdOa2eEEqnG18
4c9c6OJauDr1GdUSvGlCA/viewform?usp=sf_link

8. Survey Result Comment:
The chart shows that most of HKBU
year 1 students know about wireless
charging and do not know its working
principles. And most of them accept
wireless charging and they would like
to try mobile phone that can be
charged wirelessly as almost 60% of
them think that wireless charging is
convenient. But charging speed are
thought to be slower than
conventional ways.
0
10
20
30
40
50
60
70
Do you know
wireless
charging?
Do you know
the principle of
wireless
charging?
Will you use
the new mobile
phone with
wireless
charging?
Do you think
wireless
charging can
be accepted by
most of
people?
Do you think
wireless
charging is
convenient?
Do you think
wireless
charging is
faster than
tranditional
ways to
charge?
HKBU Year 1 students' understanding about
wireless charging
YES NO

9. Survey Result
3%
44%
27%
26%
The first time that HKBU year1 students know about
wireless charging
One month ago One year ago Haven't known it yet When the iPhone 8 came out
Comment:
A majority of HKBU year 1 students
have known about wireless charging
for more than one year, but quite a few
of them have not learned about
wireless charging until the new iPhone
came out.

10. Survey Result
Comment:
It is thought that wireless charging can
be applied to five other fields which
are watches, public facilities, TV and
other appliances, cars and robots.
Applying wireless charging technology
in transportations is supported by
most of the HKBU year 1 students. Few
of them think that robots can be
charged wirelessly.
16%
40%
11%
25%
8%
The field that HKBU year 1 students think wireless
charging technology can be appied
TV or other electrical appliances Vehicles
Watches Public facilities
Artificial intelligence

11. Applications (low power)
Cellphones
• Safe
• Convenient
• Reliable

12. Applications (high power)
Vehicles & parking
spots
• Convenient
• Charge the car while
shopping or catching
a movie

13. Applications [Electronically charged highways]
Korea paved a 12-kilometer-
long highway with wireless
charging in 2014.
Induction charging is already
powering buses in
Utah and in Germany.

14. Evaluation [Advantages]
• Protected connections — Prevent
corrosion due to elements such as
oxygen and water as the
electronics are all enclosed.
• Increased convenience and
aesthetic quality — No need for
cables.

15. Evaluation [Advantages]
• Eliminate sparks and debris
associated with wired contacts
• Reduced cost associated with
maintaining mechanical
connectors

16. Evaluation [Disadvantages]
(applicable for low power charging)
• Slower charging rate – Due to the lower efficiency, devices take longer to
charge when supplied power is the same amount.
• Inductive charging also requires drive electronics and coils in both device and
charger, increasing the complexity and cost of manufacturing.
• heat generation

17. Conclusion
Wireless charging technology is developing in an impressive way, and it begins to
appear in different fields, especially the sophisticated ones.
Because of its safety, convenience and the ease to operate, it is accepted by the
general publics. Meanwhile, the concern also exists for various reasons.
In conclusion, wireless charging technology is worthy to be trusted and looked
forward to its further developments.

18. References
https://www.wired.com/2013/08/induction-charged-buses/
https://powerbyproxi.com/wireless-charging/#how-does-wireless-charging-work
https://en.wikipedia.org/wiki/Inductive_charging

19. Thank you for listening!