Wireless Power Transmitter FOD Using Peak Frequency Q Calibration
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Solution Overview
Problem
Existing wireless power transmission systems face challenges in accurately detecting foreign objects in the charging area, leading to reduced efficiency and potential overheating due to increased ambient temperature, which can cause power waste and damage to the transmitter and receiver.
Innovation Solution
A method for detecting foreign objects by 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, and comparing it with predetermined thresholds to accurately identify the presence of foreign objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless power transmission is performed using electromagnetic induction or resonance, then power can be transferred wirelessly to mobile devices, but foreign objects in the charging area may be heated due to induced electromagnetic signals
Solution Approach 1:
The system performs foreign object detection before initiating full wireless power transmission by measuring quality factor at peak frequency. This preliminary detection identifies potential foreign objects that could be heated, allowing the system to prevent power transmission to areas with foreign objects present
Solution Approach 2:
The system continuously monitors the quality factor of the resonant circuit during wireless power transmission. When the measured quality factor deviates from expected values indicating foreign object presence, the system provides feedback to control the power transmission, reducing or stopping power delivery to prevent foreign object heating
2Reliability
If foreign object detection is performed using quality factor measurement at reference frequency, then foreign objects can be detected, but detection accuracy is reduced when peak frequency shifts occur
Solution Approach 1:
Instead of measuring quality factor at a fixed reference frequency, the system dynamically identifies the peak frequency of the resonant circuit by sweeping through a frequency range and detecting where maximum current or voltage occurs. The quality factor is then measured at this dynamically determined peak frequency, ensuring accurate measurements even when operating conditions cause frequency shifts
Solution Approach 2:
The system implements a feedback loop that continuously monitors the resonant circuit characteristics, identifies peak frequency shifts, and adjusts the measurement frequency accordingly. This adaptive feedback mechanism maintains measurement accuracy despite changes in loading conditions, temperature, or component variations
3Productivity
If foreign objects are not accurately detected, then wireless charging can proceed without interruption, but power waste and overheating occur reducing system efficiency
Solution Approach 1:
The system performs quality factor measurement and foreign object detection at the peak frequency before initiating or continuing wireless power transmission. This preliminary check ensures that power is only transmitted when no foreign objects are present, preventing energy waste while maintaining charging continuity when conditions are safe
Solution Approach 2:
The system continuously monitors quality factor during operation and compares it against threshold values. When foreign objects are detected through quality factor degradation, feedback control stops or reduces power transmission to prevent energy waste, while allowing uninterrupted charging when quality factor remains within acceptable ranges
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 method enhances the detection of foreign objects, minimizing power waste and overheating by accurately identifying and responding to foreign objects, thereby improving system safety and efficiency.
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
attempts have been made to radiate electromagnetic waves such as high frequencies, microwaves and lasers to transfer electric energy
Implementation Method 3
The electromagnetic resonance method uses an electric field or a magnetic field instead of using electromagnetic waves or current
Implementation Method 4
This technology is a RF wireless power transmission method using a rectenna. The rectenna is a combination of an antenna and a rectifier and means an element for directly converting RF power into DC power
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.