Wireless Charging Foreign Object Detection via Peak Frequency Shift
Find Innovative SolutionsGenerate Solutions
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 overheating due to increased temperatures, resulting in power waste and damage to the wireless power transmitter and receiver.
Innovation Solution
A method for detecting foreign objects involves dynamically calibrating a measured quality factor value based on the shift of a current peak frequency from a reference peak frequency, calculating a quality factor slope using output voltage levels, and comparing it with predetermined thresholds to accurately identify foreign objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If quality factor measurement is performed at a fixed reference frequency, then the detection method is simple, but detection accuracy deteriorates when peak frequency shifts occur
Solution Approach 1:
The patent dynamically adjusts the measurement frequency to track the peak frequency of the resonant circuit. Instead of using a fixed reference frequency, the system identifies the actual peak frequency through scanning or feedback and performs quality factor measurements at this dynamically determined frequency, thereby maintaining measurement accuracy despite frequency shifts caused by foreign objects or environmental changes
Solution Approach 2:
The system implements a feedback mechanism where the measured peak frequency is used to adjust subsequent measurement operations. By continuously monitoring the resonant frequency and adapting the measurement frequency accordingly, the system ensures that quality factor measurements are always performed at the optimal frequency point, resolving the contradiction between simple fixed-frequency measurement and accurate variable-frequency detection
2Productivity
If foreign object detection is not performed, then the charging process is continuous and efficient, but temperature increases causing power waste and potential damage
Solution Approach 1:
The patent performs foreign object detection before initiating the power transmission process. By measuring the quality factor of the resonant circuit in advance and comparing it against reference values or thresholds, the system identifies the presence of foreign objects beforehand. This preliminary detection prevents power transmission that would otherwise cause dangerous heating, thereby eliminating the contradiction between continuous charging and safety
Solution Approach 2:
The system uses the detrimental effect of foreign objects (which alter the resonant frequency and quality factor) as a detection mechanism. By monitoring these changes, the system converts the harmful presence of foreign objects into a useful detection signal, enabling early warning and prevention of overheating while maintaining efficient charging when no foreign objects are present
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
This approach enhances the accuracy of foreign object detection, minimizing power waste and heating issues by adaptively applying the detection method based on quality factor and peak frequency shifts, thereby ensuring safe and efficient wireless charging.
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
If a conductor which is not a wireless power receiver, that is, a foreign object (FO), is present in a wireless charging area, an electromagnetic signal received from a wireless power transmitter may be induced in the FO, thereby increasing in temperature
Implementation Method 3
an electromagnetic signal received from a wireless power transmitter may be induced in the FO, thereby increasing in temperature
Implementation Method 4
The electromagnetic resonance method uses an electric field or a magnetic field instead of using electromagnetic waves or current
Data Source
Figure 1
Figure 2
Figure 3
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.