Wireless Power Coil Foreign Object Detection Using Camera and Impedance
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Solution Overview
Problem
Existing wireless power transfer systems face challenges in detecting and preventing foreign objects from interfering with the charging process, which can lead to inefficiencies and safety issues.
Innovation Solution
A two-stage foreign object detection system that uses cameras to observe the charging area and an impedance measurement circuit to identify foreign objects, triggering a failsafe operation when objects are detected, ensuring safe and efficient charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-stage foreign object detection system is implemented, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The detection system is divided into two distinct stages: a first stage using visual imaging to detect potential foreign objects, and a second stage using impedance measurement to confirm their presence. This segmentation allows each stage to specialize in specific detection tasks, improving overall reliability while managing system complexity through functional decomposition
Solution Approach 2:
The imaging system serves as an intermediary between environmental monitoring and impedance measurement. It processes visual information to identify potential foreign objects and triggers impedance measurement only when necessary, acting as a mediator that reduces unnecessary impedance measurements while maintaining detection reliability
2Measurement precision
If impedance measurement is continuously performed, then detection precision is improved, but energy consumption increases
Solution Approach 1:
Impedance measurement is performed periodically but only when triggered by the imaging system detecting a potential foreign object. This periodic action replaces continuous impedance measurement, maintaining detection precision for actual foreign objects while significantly reducing energy consumption during normal operation without foreign objects present
Solution Approach 2:
The imaging system performs preliminary detection of potential foreign objects before triggering impedance measurement. This preliminary action filters out false positives and ensures impedance measurement is only activated when there is visual evidence of a foreign object, optimizing energy usage while maintaining detection precision
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
The system effectively detects foreign objects and initiates failsafe operations, ensuring the reliability and safety of the wireless power transfer process by preventing interference and maintaining efficient energy transfer.
Implementation Method 1
an impedance measurement circuit measures an impedance of a wireless power transfer coil of the GTA
Implementation Method 2
at least one camera is positioned to observe a charging position with at least one ground transceiver assembly and an area surrounding the charging position
Data Source
AI summary
Foreign objects impinging on a ground transceiver assembly (GTA) of a wireless power transfer (WPT) station are detected using a two-stage foreign object detection system. In a first stage, at least one camera is positioned to observe a charging position of the GTA and an area surrounding the charging position. In a second stage, an impedance measurement circuit measures an impedance of a wireless power transfer coil of the GTA. An imaging processor analyzes images from the at least one camera to identify changes or features indicative of introduction of a foreign object onto an exposed surface of the GTA or in the area surrounding the charging position. A foreign object detection (FOD) controller triggers an impedance inspection of the GTA by the impedance measurement circuit and initiates a failsafe operation when movement of an object crossing into or over the charging position is detected.