Wireless Power Transfer Coil Array with Phase-Shifted Driver Control
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Solution Overview
Problem
Existing wireless power transfer systems face challenges in adjusting the magnetic field to provide varying power levels to different devices and efficiently detecting device locations on a transmitter pad, leading to wasted power and unwanted magnetic field emissions.
Innovation Solution
The system employs phase-shifted currents in multiple transmit coils, using a controller to identify and selectively energize specific coils based on impedance changes, allowing for precise power transfer and reduced emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If all couplers are continuously energized to provide even magnetic field coverage, then power delivery coverage is improved, but power waste and unwanted magnetic field emissions increase
Solution Approach 1:
The system applies different operational states to different couplers based on local conditions. Specifically, the controller selectively energizes only those couplers that are in magnetic coupling with a chargeable device, while leaving other couplers de-energized. This local differentiation allows the system to provide targeted power delivery where needed while avoiding waste in areas without devices.
Solution Approach 2:
The system dynamically adjusts the energization state of couplers based on real-time detection of device presence and coupling conditions. The controller continuously monitors impedance changes and magnetic coupling status, then adapts which couplers are energized accordingly. This dynamic adjustment enables the system to transition from a static all-on approach to an adaptive selective energization strategy.
2Adaptability or versatility
If all couplers are continuously energized to ensure power availability, then adaptability is improved, but unwanted magnetic field emissions increase
Solution Approach 1:
The system creates different magnetic field conditions in different spatial locations by selectively energizing only the couplers that are actively coupled with chargeable devices. This local differentiation ensures that magnetic field emissions are concentrated only where power transfer is needed, rather than being distributed across the entire charging surface.
Solution Approach 2:
The system converts what would otherwise be harmful magnetic field emissions into beneficial targeted power delivery. By detecting which couplers are in magnetic coupling with devices and selectively energizing only those, the system ensures that magnetic fields are generated only where they serve a useful purpose, transforming potential harm into benefit.
3Loss of time
If impedance detection is performed on all couplers simultaneously, then device location detection speed is improved, but system complexity increases
Solution Approach 1:
The system divides the coupler array into multiple independent groups or individuals, with each coupler being detected and controlled separately. The controller performs impedance detection on couplers in a sequential or grouped manner rather than attempting to detect all couplers as a single unit. This segmentation allows for manageable detection complexity while maintaining comprehensive coverage.
Solution Approach 2:
The system performs impedance detection periodically across different couplers rather than continuously monitoring all couplers simultaneously. The controller cycles through detecting impedance changes on individual couplers or groups of couplers in sequence, which reduces the instantaneous computational and control complexity while still achieving fast overall detection through efficient time-multiplexed operation.
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 enables efficient power delivery to specific devices while minimizing waste and emissions by dynamically adjusting the magnetic field and coil energization, optimizing power handling and transfer efficiency.
Implementation Method 1
a first driver circuit having a first output impedance while driving a plurality of couplers with a first current having a first phase to generate the wireless field
Implementation Method 2
a plurality of couplers each configured to wirelessly couple the charging power to one or more receiver couplers
Data Source
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AI summary
An apparatus comprises a first driver circuit having a first output impedance while driving a plurality of couplers with a first current having a first phase to generate a wireless field. A second driver circuit drives the plurality of couplers with a second current having a second phase. A controller causes the second driver circuit to sequentially drive each of the plurality of couplers with the second current while causing the first driver circuit to simultaneously drive the other couplers with the first current. The controller identifies a subset of the plurality of couplers based on detecting a change from the first output impedance in response to each of the plurality of couplers being sequentially driven with the second current. The controller selectively energizes the subset of the plurality of couplers via one or both of the first and second driver circuits to wirelessly transfer the charging power.