Planar Receiver Coil Switching for Stable Wireless Power Coupling
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Solution Overview
Problem
Current wireless power transfer systems face challenges in maintaining efficient power transfer due to large coupling-factor variations, which can result in improper charging or damage to receivers depending on their proximity to the transmitter.
Innovation Solution
The implementation of a wireless power receiver arrangement featuring a planar inductor arrangement with a reconfigurable switching network allows for adaptive adjustment of the inductance and coupling factor, ensuring efficient power transfer across varying distances and preventing damage from high coupling factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the transmitter operates at high current to provide power to distant receivers, then power delivery capability is improved, but receivers located close to the transmitter may be damaged due to excessive coupling
Solution Approach 1:
The receiver inductance is made dynamically adjustable through a reconfigurable switching network that can change the number of active coil segments. This allows the receiver to adapt its inductance value based on its distance from the transmitter, enabling safe operation both near and far from the transmitter while maintaining efficient power transfer at all ranges.
Solution Approach 2:
The system changes the inductance parameter of the receiver based on operating conditions. By detecting the coupling factor or distance, the receiver adjusts its inductance value to maintain optimal power transfer efficiency while preventing damage from excessive coupling, thus resolving the contradiction between power delivery and safety.
2Device complexity
If the receiver uses a fixed inductance value, then device complexity is reduced, but power transfer efficiency varies significantly with distance from the transmitter
Solution Approach 1:
The receiver inductor is divided into multiple segments that can be independently switched. This segmentation allows the inductance to be adjusted in discrete steps by activating different combinations of segments, providing a balance between complexity and performance. The segmented structure enables efficient power transfer at various distances without requiring a completely complex continuous adjustment mechanism.
Solution Approach 2:
The switching network dynamically reconfigures the inductor segments based on the operating distance from the transmitter. This dynamic adjustment optimizes power transfer efficiency for both near and far receivers while maintaining a relatively simple overall device structure, as the same physical inductor serves multiple inductance values through switching.
3Power
If the receiver inductance is increased to improve coupling with distant transmitters, then power transfer to far receivers is improved, but the coupling factor becomes too high for receivers located close to the transmitter
Solution Approach 1:
The receiver inductance parameter is changed based on the distance from the transmitter. When the receiver is far from the transmitter, a higher inductance value is selected to improve coupling. When the receiver is close to the transmitter, a lower inductance value is selected to prevent excessive coupling. This parameter adaptation resolves the contradiction between power transfer to distant receivers and safety for close receivers.
Solution Approach 2:
The inductance value is made dynamic rather than fixed, allowing the system to respond to changing operating conditions. The switching network enables real-time adjustment of inductance based on detected coupling conditions, ensuring optimal performance and safety across the full range of possible distances from the transmitter.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables wireless power transfer systems to efficiently support multiple receivers simultaneously, regardless of their location or power demands, while maintaining safe operational conditions by dynamically adjusting the coupling factor.
Implementation Method 1
a wireless power receiver arrangement for receiving an electromagnetic field from a wireless power transmitter
Implementation Method 2
whose number of turns and consequently the inductance is selectively changed by means of a switching network
Data Source
AI summary
The disclosure relates to wireless a power receiver arrangement including a load, a planar inductor arrangement comprising a plurality of coil segments, and a reconfigurable switching network electrically coupled between coil segments of the plurality of coil segments. The coil segments span across respective areas of a plurality of areas and the load. The reconfigurable switching network includes a plurality of switches configured to interconnect at least a coil segment from the plurality of coil segments which spans across a smallest area of the plurality of areas according to a switching configuration to obtain a closed electrical circuit for powering the load with electrical energy from the electromagnetic field. The arrangement further includes a controller configured to determine the switching configuration in order to reduce a variation of an electromagnetic coupling of the planar inductor arrangement to the wireless power transmitter.