Wireless Power Receiver Foreign Object Detection via Peak Shift
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Solution Overview
Problem
Existing wireless charging technologies face challenges in accurately detecting foreign objects in the charging area, which can lead to reduced efficiency and potential damage due to overheating.
Innovation Solution
A wireless power receiver that dynamically calibrates the measured quality factor value based on the shift of the current peak frequency from a reference peak frequency, using a foreign object detection method that calculates a quality factor slope and compares it with a predetermined threshold value to accurately detect foreign objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If magnetic induction method is used for wireless power transfer, then power transfer efficiency is high and large power can be transferred, but transmission distance is limited to 1 cm or less requiring the device to be located adjacent to the charger
Solution Approach 1:
The patent combines magnetic induction method and electromagnetic resonance method in a single wireless power transfer system. The system includes both a magnetic induction coil and an electromagnetic resonance coil, allowing it to operate in either mode or both modes simultaneously depending on the charging requirements and distance, thus resolving the contradiction between high power transfer capability and limited transmission distance
Solution Approach 2:
The patent implements dynamic switching between magnetic induction mode and electromagnetic resonance mode based on real-time detection of device position, power requirements, and charging status. The controller selectively activates the appropriate coil type or combination, enabling the system to adaptively optimize both power transfer capability and transmission distance under different operating conditions
2Device complexity
If simple quality factor measurement is used for foreign object detection, then detection process is simple, but detection accuracy is insufficient leading to power waste and heating issues
Solution Approach 1:
The patent implements a feedback-based foreign object detection system that continuously monitors multiple parameters including quality factor, impedance, temperature, and power consumption. The system compares real-time measurements with reference values and adjusts power transmission accordingly, providing accurate foreign object detection while preventing power waste and overheating through continuous feedback control
Solution Approach 2:
The patent uses the existing wireless power transfer coils and circuitry to perform multiple functions: power transmission, quality factor measurement, impedance detection, and foreign object detection. By utilizing the same hardware components for multiple detection purposes, the system achieves high detection accuracy without significantly increasing device 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 method enhances the accuracy of foreign object detection, minimizing power waste and heating issues by adaptively applying detection methods based on quality factor and peak frequency shifts.
Implementation Method 1
Wireless power transmission or wireless energy transfer refers to technology for wirelessly transmitting electric energy from a transmitter to a receiver using the magnetic induction principle
Implementation Method 2
The electromagnetic resonance method uses an electric field or a magnetic field instead of using electromagnetic waves or current
Implementation Method 3
A secondary sensing coil is configured to generate a signal responsive to a magnetic flux field generated during the wireless power transfer
Data Source
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AI summary
The present invention relates to a method for detecting foreign material, and an apparatus and a system therefor, and a method for detecting foreign material in a wireless power transmitter, according to one embodiment of the present invention, comprises the steps of: measuring a quality factor value, which corresponds to a reference operation frequency, when an object is sensed; searching for a current peak frequency having a maximum quality factor value within an operation frequency band; receiving, form a wireless power receiver, a foreign material detection state packet including information on a reference peak frequency; correcting the measured quality factor value by using a difference value between the current peak frequency and the reference peak frequency; and determining whether the foreign material exists by comparing the corrected quality factor value with a predetermined quality factor threshold value. Therefore, the present invention has an advantage of enabling foreign material to be more effectively and accurately detected.