Wireless Power Feeding Foreign Substance Detection via Dynamic Threshold
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Solution Overview
Problem
Existing wireless power feeding systems, such as electromagnetic induction and magnetic field resonance systems, face challenges in accurately detecting foreign substances in magnetic fields due to fluctuations in electric characteristic values like the Q factor, which are influenced by the quantity of conductors in the power receiving apparatus, making it difficult to set appropriate thresholds for detection across various types of apparatuses.
Innovation Solution
A power feeding apparatus and method that includes a power feeding unit, a measuring unit, and a foreign substance detection unit, which sets and compares a threshold value based on the quantity of conductors in the power receiving apparatus, using a statistic of electric characteristic values measured with AC signals of different frequencies to accurately detect foreign substances in the magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed threshold is used for foreign substance detection based on electric characteristic values, then the detection method is simple and low cost, but the detection accuracy deteriorates when applied to different types of power receiving apparatuses with varying quantities of conductors
Solution Approach 1:
The patent implements dynamic threshold adjustment by having the power receiving apparatus transmit its specific electric characteristic values (Q factor, impedance, power consumption) to the power feeding apparatus. The system then dynamically sets the detection threshold based on these apparatus-specific parameters, allowing accurate foreign substance detection across different device types without requiring fixed universal thresholds
Solution Approach 2:
The patent changes the detection parameter from a fixed threshold to a variable threshold that adapts to different power receiving apparatuses. By using apparatus-specific electric characteristic values as the basis for threshold determination, the system maintains detection simplicity while achieving accurate foreign substance detection across diverse device configurations
2Ease of operation
If the power feeding apparatus uses a generic detection threshold, then the system is easy to operate, but it cannot accurately detect foreign substances across various power receiving apparatuses
Solution Approach 1:
The power receiving apparatus automatically provides its own electric characteristic values (Q factor, impedance, power consumption) to the power feeding apparatus. This self-service mechanism eliminates the need for manual threshold configuration or complex calibration procedures, maintaining ease of operation while enabling accurate detection through apparatus-specific parameters
3Measurement precision
If the system accounts for different quantities of conductors in various power receiving apparatuses, then detection accuracy improves, but the system complexity increases
Solution Approach 1:
The patent creates a universal detection framework where the power receiving apparatus serves multiple functions: it is both the power receiver and the source of its own detection parameters. By transmitting its electric characteristic values, the apparatus enables accurate detection without requiring separate calibration devices or complex configuration systems, achieving universality across different device types
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 substances in magnetic fields, preventing heat generation and ensuring safe power feeding by setting appropriate thresholds tailored to the specific power receiving apparatus, thereby improving the reliability of wireless power transmission systems.
Implementation Method 1
a power feeding unit (110, 410) supplying electric power through a magnetic field
Implementation Method 2
when a foreign substance of a conductor (such as metal) enters into the magnetic field, an eddy current may flow through the foreign substance and the foreign substance may generate heat
Data Source
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AI summary
A power feeding apparatus is provided. The power feeding apparatus includes a power feeding unit configured to supply electric power to a power receiving apparatus through a magnetic field; a measuring unit configured to measure an electric characteristic value and to generate a measurement value; a power receiving unit configured to provide a set value; and a foreign substance detection unit configured to detect a foreign substance in the magnetic field based on the set value and the measurement value. A power receiving apparatus, a power feeding system, and a method of controlling power feeding are also provided.