Wireless Charging Coil Positioning for Misalignment and Foreign Object Loss
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Solution Overview
Problem
Existing charging devices struggle to distinguish between power losses caused by foreign objects and positional misalignment of the receiver coil, leading to premature cutoff of power transmission.
Innovation Solution
A charging device that includes a power transmitter coil, a processor, and a memory, which calculates the ratio of received power to transmitted power and limits power transmission if the ratio falls below a threshold, while also adjusting the position of the power transmitter coil to maximize efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charging device cuts off transmitted power when power loss exceeds a threshold, then safety is improved by preventing foreign object heating, but charging continuity deteriorates due to false detection of positional misalignment as foreign objects
Solution Approach 1:
The patent segments the power loss detection into two distinct components: foreign object detection based on impedance changes and positional misalignment detection based on communication status. This segmentation allows the system to differentiate between the two causes of power loss and apply appropriate responses, resolving the contradiction by preventing false cutoffs while maintaining safety.
Solution Approach 2:
The patent employs feedback mechanisms by monitoring both impedance changes and communication status between transmitter and receiver. The communication feedback indicates whether the receiver is properly positioned and receiving power, while impedance feedback indicates the presence of foreign objects. This dual feedback system enables accurate differentiation and maintains charging continuity when appropriate.
2Temperature
If the charging device limits transmitted power when power loss is detected, then heat generation is reduced, but charging efficiency deteriorates due to inability to distinguish between foreign objects and positional misalignment
Solution Approach 1:
The patent segments the power loss response into two pathways: when communication is interrupted, the system adjusts coil position to restore alignment; when communication continues but power loss exists, the system limits power to prevent foreign object heating. This segmentation maintains charging efficiency by avoiding unnecessary power limitation while controlling heat generation when required.
Solution Approach 2:
The patent changes operational parameters dynamically based on the detected condition: communication status and impedance measurements trigger different responses. When misalignment is detected, the system changes the position parameter of the coil; when foreign objects are detected, the system changes the power level parameter. This adaptive parameter adjustment optimizes both heat control and charging efficiency.
3Device complexity
If the charging device uses communication interruption to detect positional misalignment, then detection simplicity is improved, but detection capability deteriorates in regions where communication is not interrupted but misalignment exists
Solution Approach 1:
The patent merges two detection methods: communication-based misalignment detection and impedance-based foreign object detection. By combining these methods, the system overcomes the limitation of communication-only detection and achieves comprehensive monitoring that maintains both simplicity and precision in detecting both positional misalignment and foreign objects.
Solution Approach 2:
The patent makes the impedance detection mechanism serve multiple functions: it detects both positional misalignment and foreign objects. This multi-functionality allows the simple impedance measurement to provide comprehensive diagnostic information, improving detection accuracy without significantly increasing system complexity.
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
The device effectively continues charging even with positional misalignment or foreign objects present, by limiting power transmission to prevent heat generation and adjusting the coil position for optimal efficiency.
Implementation Method 1
an induced electromotive force by electromagnetic induction is generated by causing a magnetic flux generated by an alternating current fed to a power transmitter coil to pass through a power receiver coil
Implementation Method 2
an induced electromotive force by electromagnetic induction is generated by causing a magnetic flux generated by an alternating current fed to a power transmitter coil to pass through a power receiver coil incorporated in a terminal device
Data Source
AI summary
In a charging device, a terminal device including a power receiver coil that receives wirelessly transmitted power is placed on a charging stand to perform noncontact charging. The charging device includes a power transmitter coil, a memory, and a processor coupled to the memory. The power transmitter coil transmits electric power to the terminal device. The processor is configured to: cause the power transmitter coil to transmit electric power; acquire magnitude of transmitted power that the processor causes to be transmitted; acquire magnitude of received power received by the power receiver coil; calculate a ratio of the received power to the transmitted power; and limit the transmitted power in a case where the ratio is smaller than a threshold.