Capacitive power transfer to car through wheel - is it possible?
(2012) In CODEN:LUTEDX/TEIE EIE920 20121Industrial Electrical Engineering and Automation
- Abstract
- Introduction: This work aims to evaluate the possibility to transfer electrical
power from a metal plate to the steel-cord within a car tire. If the tire stands on the
plate, a connecting surface occurs which can be interpreted as a capacitor, where
the rubber compound acts as a dielectric.
Method: First the impedance of the tire is evaluated: An analytical model is
set-up to describe the system; a nite element simulation is made using the FEMM
software and nally measurements using a Hewlett Packard 4194A impedance analyzer
is made on a Dunlop SP Sport Maxx Tire.
Secondly, the possible power transfer is analyzed, both by creating an analytical
model including the wheel impedance and a load, and by doing experiments on
a real... (More) - Introduction: This work aims to evaluate the possibility to transfer electrical
power from a metal plate to the steel-cord within a car tire. If the tire stands on the
plate, a connecting surface occurs which can be interpreted as a capacitor, where
the rubber compound acts as a dielectric.
Method: First the impedance of the tire is evaluated: An analytical model is
set-up to describe the system; a nite element simulation is made using the FEMM
software and nally measurements using a Hewlett Packard 4194A impedance analyzer
is made on a Dunlop SP Sport Maxx Tire.
Secondly, the possible power transfer is analyzed, both by creating an analytical
model including the wheel impedance and a load, and by doing experiments on
a real tire. The experiments and simulations are conducted both with and without
a resonant inductor. LTspice models are made to support the practical results as
far as possible and to investigate the limits for the capacitive power transfer.
Finally, a discussion is held regarding which parameters that can be improved
to enhance the technique.
Results: The impedance measurements show that the impedance coupling has a
capacitance of around 200 pF, and an equivalent series resistance which is inversely
dependent on the frequency and has a value of 4400
at a frequency of 10 kHz.
The LTspice simulations show that the imperfections in the transformer and
the inductance that are used in the practical experiments give rise to a lot of losses.
This makes the results from the analytical model and the practical experiments
dier, especially when a resonant inductance is introduced.
For a square wave source voltage of 1600 V and 10 kHz, and a load of 50 k
,
the analytical model give a load power of 20.1 W with an efficiency of 89 %. The
practical experiments give a load power of 19.5 W with an efficiency of 81 % when a
DC-link voltage of 30 V which results in a voltage about 1600 V on the secondary
side of the transformer - is used. For the same source voltage and load conditions,
but with a resonant inductor introduced, the simulations give a load power of 34 W
with an efficiency of 89 %. The practical experiments give a load power of 25 W
with an efficiency of 76% (33 V out from the DC link).
Conclusion: This thesis shows that the impedance feature of the tire that is investigated
makes it inappropriate for a big electrical power transfer. The capacitive
element of the impedance can be compensated for with a resonant inductor, but the
resistive part of the tire impedance is much too big to pass a lot of electrical energy.
With a dierent rubber compound though, that would have a smaller dielectric loss
angle, the technique could be worth evaluating more. For example, a tire with silica
filler instead of carbon black filler - which is used in the tire of this project - could
be worth analyzing. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/3710545
- author
- Hall, Sebastian
- supervisor
-
- Avo Reinap LU
- Mats Alaküla LU
- organization
- course
- EIE920 20121
- year
- 2012
- type
- H3 - Professional qualifications (4 Years - )
- subject
- publication/series
- CODEN:LUTEDX/TEIE
- report number
- 5305
- language
- English
- id
- 3710545
- date added to LUP
- 2013-05-21 06:49:40
- date last changed
- 2014-09-04 08:29:55
@misc{3710545, abstract = {{Introduction: This work aims to evaluate the possibility to transfer electrical power from a metal plate to the steel-cord within a car tire. If the tire stands on the plate, a connecting surface occurs which can be interpreted as a capacitor, where the rubber compound acts as a dielectric. Method: First the impedance of the tire is evaluated: An analytical model is set-up to describe the system; a nite element simulation is made using the FEMM software and nally measurements using a Hewlett Packard 4194A impedance analyzer is made on a Dunlop SP Sport Maxx Tire. Secondly, the possible power transfer is analyzed, both by creating an analytical model including the wheel impedance and a load, and by doing experiments on a real tire. The experiments and simulations are conducted both with and without a resonant inductor. LTspice models are made to support the practical results as far as possible and to investigate the limits for the capacitive power transfer. Finally, a discussion is held regarding which parameters that can be improved to enhance the technique. Results: The impedance measurements show that the impedance coupling has a capacitance of around 200 pF, and an equivalent series resistance which is inversely dependent on the frequency and has a value of 4400 at a frequency of 10 kHz. The LTspice simulations show that the imperfections in the transformer and the inductance that are used in the practical experiments give rise to a lot of losses. This makes the results from the analytical model and the practical experiments dier, especially when a resonant inductance is introduced. For a square wave source voltage of 1600 V and 10 kHz, and a load of 50 k , the analytical model give a load power of 20.1 W with an efficiency of 89 %. The practical experiments give a load power of 19.5 W with an efficiency of 81 % when a DC-link voltage of 30 V which results in a voltage about 1600 V on the secondary side of the transformer - is used. For the same source voltage and load conditions, but with a resonant inductor introduced, the simulations give a load power of 34 W with an efficiency of 89 %. The practical experiments give a load power of 25 W with an efficiency of 76% (33 V out from the DC link). Conclusion: This thesis shows that the impedance feature of the tire that is investigated makes it inappropriate for a big electrical power transfer. The capacitive element of the impedance can be compensated for with a resonant inductor, but the resistive part of the tire impedance is much too big to pass a lot of electrical energy. With a dierent rubber compound though, that would have a smaller dielectric loss angle, the technique could be worth evaluating more. For example, a tire with silica filler instead of carbon black filler - which is used in the tire of this project - could be worth analyzing.}}, author = {{Hall, Sebastian}}, language = {{eng}}, note = {{Student Paper}}, series = {{CODEN:LUTEDX/TEIE}}, title = {{Capacitive power transfer to car through wheel - is it possible?}}, year = {{2012}}, }