This document analyzes the efficiency of wireless power transfer using high-temperature superconductor (HTS) coils. It discusses the history of wireless power transfer and describes resonance inductive coupling. The theoretical approach and experimental setup are explained, involving different test cases using HTS and copper coils. Major power losses are identified. HTS coils have advantages like higher transfer efficiency compared to copper, but also disadvantages like a limited operating frequency range. Future research opportunities are identified to improve the technology.

1. ANALYSIS ON EFFICIENCY OF WIRELESS
POWER TRANSFER USING HTS COIL

2. Overview
History of WPT
Resonance inductive coupling
Theortical approach
Experimental Setup
Different cases
Major losses
Advantages and disadvantages
Future research
Conclusion
References

3. Wireless electricity way
back in the 1800s……..
In the year 1891,Nikola Tesla
proposed the method of
wireless transmission of
electric power
One of the greatest
breakthroughs of science at
that time

4. Built the wardenclyffe tower
which could broadcast power
wirelessly,is called off as it
radiated power into
surroundings raising issues of
•Power theft
•Health concerns
The Wardenclyffe Tower
A dream crashes……

5. Resonance Inductive Coupling(RIC)
The capacitor and inductor forms the resonator.
Charge oscillates between inductor (as magnetic field)
and capacitor (as electric field.)
• This type of oscillation is called
resonance if the reactance's
of the inductor and capacitor
are equal.

6. CONVENTIONAL SYSTEM

7. HIGH TEMP SUPER CONDUCTOR
The electrical resistivity of a metallic conductor decreases gradually as
temperature is lowered and at the same time its conductivity becomes infinity.

8. • BSCCO needs to be hole-doped by an excess of oxygen atoms in order to
superconductor.
• By changing the oxygen content Tc can thus be altered at will.
• Even though BSCCO has a higher upper critical field than YBCO due to
some variations in chemical composition, YBCO are preferred to BSCCO
though they are much more difficult to fabricate.
• Experimental setup

9. Theoretical approach
Couple mode theory
The wireless power transfer can be presented as a set of first order linear
differential equations
Assumptions
• Internal loss of coils is comparatively small.
• Frequency range of operation is narrow enough to assume inductance
and internal capacitance of the coils be constant.

10. Circuit model

11. Assumption
• Transmitting and receiving coil should have same resistance
and inductance.
• The coupling capacitors,should be such that both capacitors
must have the same rating at resonant condition.

12. Experimental setup

13. • Superconductors preferred :BSCCO (Bismuth Strontium
Calcium Copper Oxide).YBCO (Yttrium Barium Copper
Oxide)
• Shape : corresponds to a ribbon which can be wound easily
can also be used.
• Treated with liquid nitrogen to enhance the thermal stability.
• Kapton tape is used as insulation between HTS tapes when
winding the coils.
• Then AC power is supplied.

14. • The capacitor used can be also made of superconducting
material .
• External capacitance provided to lower the operating
frequency and to attain high efficiency and large distance
transmission.
• Booster resonator coil can be positioned between the primary
and secondary coil for large transfer distance.
• Frequency range selection for eliminating radiative loss.

15. Different case for frequency 1.4KHz to 4.3KHz
• HTS coil (as transmitting coil) to HTS coil (as receiving coil)
at 77 K
• copper coil to copper coil at 77 K
• copper coil to copper coil at RT
• copper coil at RT to HTS coil at 77 K
• copper coil at 77 K to HTS coil at 77 K
• HTS coil at 77 K to copper coil at RT
• HTS coil to copper coil at 77K

16. • The resistances of the coils were measured by RLC testing
consist of 2 parts:
• ac losses in HTS coils device. The resistances of HTS coils
• AC losses in the HTS coils contain 3 parts.
 The Transport Loss
 The Hysteresis Loss Caused by Magnetic Field
 The Eddy-Current Loss
Main losses..

17. To reduce the losses…
• Use superconducting material
• Lower the operating frequency

18. Inference
Deviation in the graph
because the transport current
becomes
higher near the resonant
frequency, and ac losses of
HTS coils
cannot be neglected under
such condition.

19. At transfer distance of 6.5 cm
1) 92.78%
2) 53.47%
3) 27.07%,

20. At transfer distance of
11cm
1)68.73%
2) 62.28%
3) 34.05%
4) 24.58%

21. • The maximum power transfer efficiency at 11 cm of a WPT system with
HTS coil as transmitting coil is 2.5 times higher than that of a WPT system
with HTS coil as receiving coil. Hence, HTS coils are more suitable for being
as a transmitting coil than as a receiving one.

22. Advantage Disadvantage
• Transfer Efficiency Will Be More
Compared To Copper Coil
• HTS coil can be used as
transmitting coil for higher
efficiencies
• Booster resonator coil can be
placed between the transmitter
and receiver coil for long
distance transmission.
• Capacitance is added inorder to
reduce radiative losses and to
maintain the coil in resonance.
• Operating frequency can be
decreased within a specific
range.If not,it will affect the
power transfer efficiency.
• Frequency below 1MHz
preferably 200KHz is
applicable for power transfer
in the present system.

23. Conclusion
• Simulation results concludes that HTS coil can give high
efficiency and can be transmit power to larger distance by
placing a booster resonator.
• Transfer efficency will be high if the HTS coil is used as
transmitting coil.

24. Future research
Wireless power transmission can be done by
• employing different coil shapes.
• adding intermediate coils.
• Using low temperature capacitors or HTS capacitors.
• Situations where we have to sign in to a power zone to
charge the devices.

25. Reference
• GuoMin Zhang, Hui Yu, Liwei Jing, Jincheng Li, Qi Liu, and
XianghuaFeng ‘Wireless Power Transfer Using High Temperature
Superconducting Pancake Coils’IEEE TRANSACTIONS ON APPLIED
SUPERCONDUCTIVITY, VOL. 24, NO. 3, JUNE 2014
• Senthil Nathan.M1, Pandiarajan.K / International Journal of Engineering
Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol.
3, Issue 1, January -February 2013, pp.1125-1130 1125 |P a g e A
Review Of Wireless Power Transmission

26. • T. Nakamura *, K. Higashikawa, I. Muta, A. Fujio, K. Okude, T. Hoshino
‘Improvement of dissipative property in HTS coil i`mpregnated with solid nitrogen’
Department of Electrical Engineering, Graduate School of Engineering, Kyoto
University, Yoshida-Honmachi, Sakyo, Kyoto 606-8501, Japan
:www.sciencedirect.com
• Alexey Bodrov and Seung-Ki SulIEEEFellow,Republic of Korea “Analysis of Wireless
Power Transfer by Coupled Mode Theory (CMT) and Practical Considerations to
Increase Power Transfer Efficiency”
• RAYMOND J.SEDWICK UNIVERSITY ARK ,MD (US)”Methods and system for long
range wireless power transfer” United States Patent Applicationpublication.Pub:US
2012/001079 A1:Pub date:Jan 12,2012