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, 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 the shift of current peak frequencies from a reference peak frequency, and calculating quality factor slopes from output voltage levels within an operating frequency band, comparing these values with predetermined thresholds to determine the presence of foreign objects.
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 loss
Solution Approach 1:
The patent performs foreign object detection before initiating wireless power transmission by measuring the quality factor of the transmitter coil. This preliminary action identifies foreign objects in advance, preventing them from being heated during charging, thus resolving the contradiction between maintaining power transfer efficiency and preventing foreign object heating hazards
Solution Approach 2:
The system continuously monitors quality factor changes during charging and compares them against reference values. When foreign objects are detected through quality factor deviation, the system provides feedback to adjust or terminate power transmission, thereby preventing foreign object heating while maintaining efficient power transfer under normal conditions
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 patent dynamically adjusts detection thresholds and quality factor reference values based on the specific receiver device being charged. By adapting detection parameters to match the expected electrical characteristics of legitimate receivers, the system achieves high detection sensitivity for foreign objects while minimizing false detections that would interrupt normal charging, thus resolving the contradiction between detection accuracy and charging continuity
Solution Approach 2:
The system employs dynamic quality factor reference values that are established during the handshaking phase and updated based on the receiver's characteristics. This dynamic adaptation allows the detection system to distinguish between legitimate receivers and foreign objects with high accuracy while avoiding false alarms, maintaining both detection precision and charging reliability
3Reliability
If quality factor measurement is performed continuously to detect foreign objects, then detection reliability improves, but energy consumption increases
Solution Approach 1:
The patent implements periodic quality factor measurements at key stages such as before charging begins and at intervals during charging, rather than continuous monitoring. This periodic approach maintains reliable foreign object detection capability while significantly reducing the energy consumption associated with constant measurements, thus resolving the contradiction between detection reliability and energy efficiency
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, minimizes power waste, and prevents overheating by adaptively applying detection methods based on quality factors and peak frequencies, ensuring safe and efficient wireless charging operations.
Implementation Method 1
The magnetic induction method uses a phenomenon that, when two coils are located adjacent to each other and then current is applied to one coil, a magnetic flux is generated to cause an electromotive force in the other coil
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
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
Data Source
AI summary
A wireless power reception method including transmitting a first foreign object status packet and a second foreign object status packet to a wireless power transmitter; receiving, from the wireless power transmitter, a first foreign object detection indicator including a positive response signal or a negative response signal for the first foreign object status packet and a second foreign object detection indicator including a positive response signal or a negative response signal for the second foreign object status packet; power receiving of performing a first power transmission procedure when both the first foreign object detection indicator and the second foreign object detection indicator include the positive response signal, or performing to a second power transmission procedure of requesting termination of power transmission or performing to a third power transmission procedure different from the termination of the power transmission when at least one of the first foreign object detection indicator and the second foreign object detection indicator includes the negative response signal.