Investigations and system design for simultaneous energy and data transmission through inductively coupled resonances
Wireless Power Transfer (WPT) with simultaneous data transmission through coupled magnetic resonators is investigated in this paper. The development of this system is dedicated to serve as a basis for applications in the field of Ambient Assisted Living (AAL), for example tracking vital parameters r...
| Main Authors: | , , |
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| Format: | Article |
| Language: | deu |
| Published: |
Copernicus Publications
2015-11-01
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| Series: | Advances in Radio Science |
| Online Access: | http://www.adv-radio-sci.net/13/217/2015/ars-13-217-2015.pdf |
| Summary: | Wireless Power Transfer (WPT) with simultaneous data transmission through coupled magnetic resonators is investigated in this
paper. The development of this system is dedicated to serve as a basis for applications in the field of Ambient Assisted Living
(AAL), for example tracking vital parameters remotely, charge and control sensors and so on. Due to these different scenarios we
consider, it is important to have a system which is reliable under the circumstance of changing positioning of the receiving
device. State of the art radio systems would be able to handle this. Nevertheless, energy harvesting from far field sources is not
sufficient to power the devices additionally on mid-range distances. For this reason, coupled magnetic resonant circuits are
proposed as a promising alternative, although suffering from more complex positioning dependency.
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Based on measurements on a simple prototype system, an equivalent circuit description is used to model the transmission system
dependent on different transmission distances and impedance matching conditions. Additionally, the simulation model is used to
extract system parameters such as coupling coefficients, coil resistance and self-capacitance, which cannot be calculated in a
simple and reliable way.
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Furthermore, a mathematical channel model based on the schematic model has
been built in MATLAB<sup>©</sup>. It is used to point out the problems
occurring in a transmission system with variable transmission distance,
especially the change of the passband's centre frequency and its bandwidth.
Existing solutions dealing with this distance dependent behaviour, namely the
change of the transmission frequency dependent on distance and the addition
of losses to the resonators to increase the bandwidth, are considered as not
inventive. First, changing the transmission frequency increases the
complexity in the data transmission system and would use a disproportional
total bandwidth compared to the actually available bandwidth. Additionally,
adding losses causes a decrease in the energy transmission efficiency.
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Based on these facts, we consider a system that changes the channel itself
by tuning the resonant coils in a way that the passband
is always at a fixed frequency. This would overcome the previously described
issues, and additionally could allow for the
possibility to run several independent transmission systems in parallel without disturbing each other. |
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| ISSN: | 1684-9965 1684-9973 |