Wireless Charging FOD Using Q-Factor Slope and Peak Frequency
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Solution Overview
Problem
Existing wireless charging technologies face challenges in accurately detecting foreign objects in the charging area, leading to reduced efficiency and potential overheating, which can result in power waste and damage to the transmitter and receiver.
Innovation Solution
A method and apparatus for detecting foreign objects using dynamic calibration of quality factor values based on shifts in peak frequencies, comparing measured quality factor slopes with predetermined thresholds, and adaptively applying detection methods to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wireless power transmission is performed in a charging area, then power transfer efficiency is improved, but foreign objects may be heated causing safety hazards and energy waste
Solution Approach 1:
The system performs foreign object detection by measuring quality factor changes before initiating full power transmission. This preliminary detection action identifies potential foreign objects in the charging area, allowing the system to prevent or adjust power transmission to avoid heating foreign objects while maintaining efficient charging when the area is clear.
Solution Approach 2:
The quality factor measurement serves as an intermediary indicator to indirectly detect the presence of foreign objects. Instead of directly detecting foreign objects or their heating, the system uses quality factor changes of the resonant circuit as a mediator to infer foreign object presence, enabling safe power transmission decisions.
2Measurement precision
If foreign object detection sensitivity is increased to prevent heating, then detection accuracy improves, but false detections increase causing charging interruptions
Solution Approach 1:
The system dynamically adjusts the quality factor threshold based on operating conditions such as transmission power level and frequency. By changing the threshold parameter adaptively rather than using a fixed value, the system maintains high detection sensitivity while reducing false positives that would interrupt normal charging operations.
Solution Approach 2:
The system uses feedback from quality factor measurements to continuously monitor charging conditions and adjust detection parameters. When quality factor changes indicate foreign object presence, the system responds by modifying power transmission or detection sensitivity, and can resume charging when the foreign object is removed, maintaining operational reliability.
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 detection of foreign objects, minimizing power waste and overheating, and ensuring safe and efficient wireless charging operations.
Implementation Method 1
wireless power transmission technology... uses 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
an electromagnetic signal received from a wireless power transmitter may be induced in the FO, thereby increasing in temperature
Data Source
AI summary
A wireless power transmitter that transmits power to a wireless power receiver, the wireless power transmitter including a wireless communication unit configured to communicate with the wireless power receiver; and a controller, wherein the wireless communication unit receives a foreign object detection (FOD) status packet from the wireless power receiver, wherein the controller determines whether a foreign object is present in a charging area of the wireless power transmitter on the basis of the FOD status packet, wherein the wireless communication unit transmits, to the wireless power receiver, a foreign object detection indicator indicating whether the foreign object is present in the charging area of the wireless power transmitter on the basis of a result of the determination, wherein the FOD status packet includes information on a reference quality factor or a reference peak frequency, wherein the FOD status packet has a length of two bytes, wherein one byte of the FOD status packet includes a 6-bit reservation field and a 2-bit mode field, and wherein all bits of the reservation field are recorded as zero.