Segmented Wireless Charging Coil for Foreign Object Detection
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Solution Overview
Problem
Existing wireless charging devices for electric vehicles interrupt the charging process when a foreign object, such as an animal or metallic item, is detected within the coupling zone, leading to incomplete battery charging due to the termination of power transfer.
Innovation Solution
A wireless charging device with a coil arrangement comprising multiple electromagnetic coils, each generating magnetic flux in different regions of the coupling zone, and an electronic power control unit that can independently switch off power to specific coils to avoid heating foreign objects while maintaining power transfer to other coils, allowing charging to continue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single large electromagnetic coil is used to fill the whole coupling zone, then the charging area is covered, but foreign objects in the coupling zone are heated up due to induction
Solution Approach 1:
The single large electromagnetic coil is divided into multiple smaller electromagnetic coils (first electromagnetic coil and second electromagnetic coil), each responsible for a specific region of the coupling zone. This segmentation allows independent control of each coil, enabling the system to disable only the coil corresponding to the foreign object's location while keeping other coils active, thus preventing foreign object heating while maintaining overall charging coverage.
2Object-affected harmful factors
If power transfer is completely terminated when a foreign object is detected, then foreign object heating is prevented, but the charging process is interrupted
Solution Approach 1:
The coil arrangement is segmented into multiple independently controllable electromagnetic coils. When a foreign object is detected in a specific region, only the corresponding coil is disabled while other coils continue to operate. This selective disabling prevents foreign object heating in the affected region while maintaining power transfer and charging continuity in regions without foreign objects.
3Object-affected harmful factors
If multiple electromagnetic coils are used with independent power control, then foreign objects can be selectively targeted, but the device complexity increases
Solution Approach 1:
The coupling zone is divided into multiple regions, each covered by a dedicated electromagnetic coil with independent power control. This segmentation enables precise targeting of foreign objects by disabling only the specific coil in the region where a foreign object is detected, rather than disabling all coils. The increased complexity is justified by the significant improvement in charging continuity and safety.
Solution Approach 2:
Each electromagnetic coil is designed to provide magnetic flux in a specific local region of the coupling zone. This local quality assignment allows the system to apply different power states (on/off) to different local regions based on foreign object detection, enabling selective prevention of foreign object heating while maintaining charging in safe regions.
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
Enables continuous inductive power transfer to electric vehicles even when foreign objects are present by selectively switching off magnetic flux in affected regions, preventing overheating and ensuring efficient battery charging.
Implementation Method 1
An electromagnetic coil arrangement 10 is provided for generating the magnetic flux 19
Implementation Method 2
the receiving unit may transform the magnetic flux into an electric voltage
Implementation Method 3
Such a coil arrangement may comprise one large electromagnetic coil that fills the whole coupling zone with the needed magnetic flux
Data Source
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AI summary
The invention is concerned with a Wireless charging device (14) for generating a time-varying magnetic flux (19) within a predefined coupling zone (20) which is provided for positioning a wireless power receiving unit (15) for an inductive power transfer, wherein an electromagnetic coil arrangement (10) is provided for generating the magnetic flux (19) and an electronic power control unit (16) is designed to control an electric power that is provided to the coil arrangement (10). The invention is characterized in that the coil arrangement (10) comprises several electromagnetic coils (11), each of which is designed to provide a part of the magnetic flux (19) in a different region (28) of the coupling zone (20), wherein the power control unit (16) is designed to switch the electric power for each of the coils (11) independently of the remaining coils (11).