Wireless Power Coil Foreign Object Detection Beyond Coil Center
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Solution Overview
Problem
Existing electronic devices using wireless power transfer technology struggle to detect foreign objects accurately, particularly when they are positioned outside the center of the power transmission and reception coils, leading to reduced power transmission efficiency or heat generation.
Innovation Solution
The method involves transmitting a first ping signal through a wireless power transfer coil, analyzing the waveform of current or voltage, calculating the Q factor, and controlling power transmission based on the Q factor to detect foreign objects at the coil's center, followed by a second ping signal and inductance measurement to identify foreign objects in the surrounding area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If foreign object detection is performed using conventional methods, then detection is possible at the center position, but detection fails in outer areas of the coil
Solution Approach 1:
The patent transitions from single-point center detection to multi-point distributed detection by placing sensors at multiple positions including outer areas of the coil. This spatial dimensionality change enables comprehensive coverage of the entire power transmission area, not just the center region.
Solution Approach 2:
The detection system is divided into multiple independent detection points distributed across different locations of the coil. Each sensor segment independently monitors its local area, and the results are combined to achieve complete coverage of the power transmission zone.
2Productivity
If power transmission continues without accurate foreign object detection, then power transmission efficiency is maintained, but safety hazards occur
Solution Approach 1:
The system performs foreign object detection before initiating power transmission and continuously monitors during transmission. By detecting foreign objects in advance and in real-time, the system prevents unsafe power transmission while maintaining efficient operation when conditions are safe.
Solution Approach 2:
The system continuously monitors power transmission parameters and foreign object presence, providing real-time feedback to control whether power transmission should continue or be interrupted. This closed-loop control ensures both safety and efficiency by adapting transmission based on current conditions.
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 enables effective detection of foreign objects regardless of their position, reducing safety-related accidents and maintaining power transmission efficiency.
Implementation Method 1
The wireless power transfer technology may include a magnetic induction method
Implementation Method 2
The wireless power transfer technology may include a magnetic resonance method
Implementation Method 3
obtain a Q factor, based on the identified waveform
Implementation Method 4
identifying inductance measured at both ends of the WPT coil, based on the identified waveform
Data Source
AI summary
An electronic device capable of transmitting and receiving wireless power may include a wireless power transfer (WPT) coil and a processor configured to be operatively connected to the WPT coil, wherein the processor may perform control to transmit a first ping signal to an external object through the WPT coil, may identify a waveform of a current or voltage measured while or after transmitting the first ping signal, may obtain a Q factor, based on the identified waveform, may control a power transmission operation by determining that the external object is a foreign object or includes the foreign object and is positioned on a center of the WPT coil when the obtained Q factor is less than a predetermined Q factor, may transmit a second ping signal to the external object through the WPT coil when the obtained Q factor is equal to or greater than the predetermined Q factor, may identify a waveform of a current or voltage while or after transmitting the second ping signal, may identify inductance measured at both ends of the WPT coil, based on the identified waveform, and may control the power transmission operation by determining that the external object is the foreign object or includes the foreign object and is positioned in a surrounding area of the WPT coil, based on the measured inductance.