ANALYSIS ON EFFICIENCY OF WIRELESS POWER TRANSFER USING HTS COIL
OverviewHistory of WPT
Resonance inductive coupling
Theortical approach
Experimental Setup
Different cases
Major losses
Advantages and disadvantages
Future research
Conclusion
References
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
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……
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.
CONVENTIONAL SYSTEM
HIGH TEMP SUPER CONDUCTORThe electrical resistivity of a metallic conductor decreases
gradually as temperature is lowered and at the same time its
conductivity becomes infinity.
• 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
Theoretical approach
Couple mode theory The wireless power transfer can be presented as a set of
first order linear differential equationsAssumptions
• 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.
Circuit model
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.
Experimental setup
• 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.
• 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.
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
• 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..
To reduce the losses…
• Use superconducting material
• Lower the operating frequency
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.
At transfer distance of 6.5
cm
1) 92.78%
2) 53.47%
3) 27.07%,
At transfer distance
of 11cm
1)68.73%
2) 62.28%
3) 34.05%
4) 24.58%
• 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.
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.
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.
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.
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
• 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
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