Wireless Power Receiver Foreign Object Detection via Load Feedback
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Solution Overview
Problem
Existing wireless power transmission systems face difficulties in accurately detecting foreign objects within the power transmission service area, especially when changes occur in the consumption power of loads, leading to potential incorrect determinations of foreign object presence.
Innovation Solution
A wireless power transmission system that includes a power transmission apparatus and a power reception apparatus, equipped with detection units and communication protocols, which analyze changes in current and voltage patterns to distinguish between foreign object presence and changes in load consumption power, using authentication and control processes to determine the presence of foreign objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If foreign object detection is performed by comparing current magnitude through transmission antenna with current magnitude through battery, then foreign object detection capability is improved, but detection accuracy deteriorates when load consumption power changes
Solution Approach 1:
The power reception apparatus transmits power reception information (consumption power data) to the power transmission apparatus, which then uses this feedback to correct the foreign object determination. The transmission apparatus adjusts the determination based on the actual power consumption of the load, allowing accurate foreign object detection even when consumption power changes occur.
Solution Approach 2:
The system changes the determination parameter from a fixed current ratio threshold to a dynamic threshold that is adjusted based on the power reception information. By varying the reference value according to actual consumption power, the system maintains accurate foreign object detection across different operating conditions.
2Device complexity
If simple current ratio comparison is used for foreign object detection, then device complexity is reduced, but detection accuracy deteriorates under varying load conditions
Solution Approach 1:
The system adds a feedback mechanism where the power reception apparatus communicates consumption power information to the transmission apparatus. This feedback enables accurate foreign object detection without requiring complex additional hardware, as the existing communication channel is utilized for transmitting power reception information.
Solution Approach 2:
The communication channel between transmission and reception apparatuses serves multiple functions: power reception information transmission and foreign object determination support. This multi-functionality avoids adding dedicated complex detection hardware while improving detection accuracy.
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 accurate detection of foreign objects even in situations where consumption power changes occur, preventing incorrect determinations and ensuring safe operation by stopping power transmission when foreign objects are detected.
Implementation Method 1
a power transmission apparatus configured to wirelessly transmit power and a power reception apparatus configured to receive the power supplied from the power transmission apparatus
Implementation Method 2
a detection unit configured to detect a change in a magnitude of a current flowing through the transmission antenna
Data Source
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AI summary
A power reception apparatus includes power reception means (209) for receiving power wirelessly supplied from a power transmission apparatus (101), voltage conversion means (203) arranged to convert the voltage of the power receive by the power reception means (201) to a voltage with a particular value, load means (200) arranged to operate with an output from the voltage conversion means (203), first detection means (206) arranged to detect a voltage or a current input to the voltage conversion means (203), and second detection means (207) arranged to detect consumption power of the load means (200), determination means (208) arranged to make a determination, based on a result of a detection performed by the first detection means (206) and a result of a detection performed by the second detection means (207), as to whether there exists a foreign object (401), which is not a target object to which power is to be transmitted, in a power transmission service area covered by the power transmission apparatus (101).