Wireless Power Transfer Foreign Object Detection With Dynamic Thresholds
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Solution Overview
Problem
Existing wireless power transmission systems face issues with false detection of foreign objects due to the reliance on power loss differences, leading to incorrect determination of object presence or absence.
Innovation Solution
A power transmitting apparatus that sets multiple thresholds for determining foreign object presence, including a first threshold for definite detection, a second threshold for no object detection, and a third threshold for indicating possible object presence, based on transmission power settings and uncertainty margins, to reduce false detection occurrences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single threshold is used for foreign object detection based on power loss, then the detection process is simple, but false detection occurs frequently
Solution Approach 1:
The single threshold detection method is segmented into three distinct thresholds: a first threshold for determining foreign object presence, a second threshold for determining no foreign object, and a third threshold for indicating possible foreign object presence. This segmentation divides the detection range into multiple zones, reducing false detections while maintaining operational simplicity.
Solution Approach 2:
The invention changes the parameter of threshold values from a single value to multiple values with different meanings. By setting different thresholds (first, second, and third thresholds) with specific relationships, the system achieves more reliable detection without significantly increasing complexity.
2Difficulty of detecting and measuring
If power loss detection is used to determine foreign object presence, then detection is straightforward, but false positives and false negatives occur
Solution Approach 1:
The detection result is segmented into three distinct outcomes: foreign object exists (power loss > first threshold), no foreign object (power loss < second threshold), and possible foreign object (power loss between thresholds). This segmentation improves measurement precision while keeping the detection method based on simple power loss measurement.
Solution Approach 2:
The invention introduces an intermediary state (possible foreign object presence) between definite presence and definite absence. This intermediary category, represented by the third threshold, acts as a buffer zone that reduces both false positives and false negatives by acknowledging uncertainty in the measurement.
3Power
If transmission power is increased to improve power reception, then received power increases, but power loss detection becomes less reliable
Solution Approach 1:
The invention makes the threshold values dynamic by setting them in relationship to each other rather than as fixed values. The first, second, and third thresholds are configured with specific relationships that adapt to different transmission power levels, maintaining detection reliability even when transmission power varies to improve received power.
Data Source
AI summary
A power transmitting apparatus sets, on the basis of transmission power set with the power receiving apparatus, a first threshold for determining whether or not a foreign object exist, and a second threshold lower than the first threshold. The first and second threshold are set so that the difference between the first and second threshold values becomes larger as the set transmission power becomes larger. The power transmitting apparatus determines: that a foreign object exists in a case where the power loss is greater than the first threshold; that a foreign object does not exist in a case where the power loss is less than the second threshold; and that there is a possibility of a foreign object existing in a case where the power loss is between the first threshold and the second threshold.