Tunable Wireless Power Device with Metallic Detuning Structure
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Solution Overview
Problem
Existing wireless power transfer technologies face challenges in efficiently transferring power over reasonable distances due to rapid power coupling fall-off and are susceptible to detuning by external metal structures, which reduces efficiency and can cause interference with other systems.
Innovation Solution
The implementation of a wireless power system using a loop antenna with a metallic structure and a magnetic material to induce eddy currents, which helps in retuning the transmit antenna and enhancing immunity to detuning, thereby maintaining efficient power transfer even in the presence of external metallic structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a transmit antenna is used for wireless power transfer, then power can be transmitted wirelessly, but external metal structures cause detuning that reduces transfer efficiency
Solution Approach 1:
A metallic detuning structure is integrated into the transmit antenna assembly and pre-configured to counteract the detuning effect of external metal structures. When an external metal object approaches the antenna, the detuning structure adjusts its electrical characteristics to produce an opposing effect that cancels out the detuning, thereby maintaining resonant frequency and power transfer efficiency.
Solution Approach 2:
The detuning structure's electrical parameters (inductance, capacitance, or resistance) are made variable to dynamically adjust and compensate for changes in the electromagnetic environment. By changing these parameters in response to detected detuning conditions, the system maintains optimal resonance and efficiency despite the presence of external metal structures.
2Ease of operation
If plane wave radiation coupling is used for wireless power transfer, then power can be transmitted over the air, but unintentional radiation interferes with other systems
Solution Approach 1:
The antenna system is designed to concentrate electromagnetic energy in a localized near-field region rather than radiating plane waves in all directions. By creating a confined evanescent field between the transmit and receive antennas, the system achieves wireless power transfer while minimizing far-field radiation that could interfere with other electronic systems.
Solution Approach 2:
The system converts what would normally be lost radiative energy into useful localized power transfer by operating in the near-field regime. The evanescent fields that would normally decay rapidly are instead harnessed for efficient short-range power transfer, while the reduced far-field radiation naturally minimizes interference with other systems.
3Productivity
If inductive coupling between transmit and receive antennas is used, then multiple devices can be charged simultaneously, but the spacing between antennas must be very close
Solution Approach 1:
The antenna system employs dynamic tuning capabilities that allow the resonant frequency and coupling characteristics to be adjusted in real-time. This dynamic adjustment enables the system to maintain efficient power transfer over varying distances and with multiple devices simultaneously, overcoming the fixed spacing limitation of traditional inductive coupling.
Solution Approach 2:
The transmit antenna system is designed to simultaneously support multiple receive antennas at different positions and orientations. By creating a distributed near-field coupling zone rather than a single-point coupling, the system can charge multiple devices at once while maintaining reasonable spacing, combining the benefits of inductive coupling with enhanced flexibility.
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 approach significantly improves the efficiency of wireless power transfer by reducing the impact of external metallic structures, allowing for effective power transfer over larger distances and minimizing interference, with transfer efficiencies maintained at approximately 68-71% even when positioned proximate to external metallic objects.
Implementation Method 1
a metallic structure spaced from the transmit antenna... The metallic structure may induce eddy currents to detune the transmit antenna
Implementation Method 2
One is based on the coupling of plane wave radiation (also called far-field radiation) between a transmit antenna and receive antenna
Data Source
AI summary
Exemplary embodiments are directed to wireless power devices. A device may include a transmit antenna and a metallic structure spaced from and configured for detuning the transmit antenna. The device may further include a circuit for tuning the transmit antenna.