Wireless Power Foreign Object Detection Using Noise Segmentation
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Solution Overview
Problem
The magnetic field used in wireless power transmission systems interferes with the detection of metallic foreign objects, particularly when high-frequency components from switching elements are present, leading to reduced detection accuracy.
Innovation Solution
A wireless power transmission system that includes a noise detection part to identify high-frequency noise and a foreign object detection part that adjusts voltage application timing based on noise detection results, improving the accuracy of metallic foreign object detection between the feeding and receiving coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a resonance circuit is used to detect metallic foreign objects during wireless power transmission, then foreign object detection capability is provided, but detection accuracy deteriorates due to high-frequency noise from switching elements
Solution Approach 1:
The patent divides the detection process into two separate functional modules: a noise detection part that specifically detects high-frequency noise components, and a foreign object detection part that detects foreign objects. This segmentation allows each module to specialize in its respective detection task, preventing noise from interfering with foreign object detection accuracy.
Solution Approach 2:
The noise detection part acts as an intermediary that identifies high-frequency noise generated by switching elements. By detecting this noise separately first, the system can then use this information to adjust or filter the foreign object detection process, thereby improving detection accuracy despite the presence of noise.
2Reliability
If voltage is applied continuously to the resonance circuit for foreign object detection, then detection coverage is maintained, but noise interference increases reducing detection reliability
Solution Approach 1:
The patent implements periodic action by having the noise detection part operate at specific intervals to detect high-frequency noise, and then using these detection results to guide the foreign object detection timing. This periodic noise detection approach allows the system to maintain reliable foreign object detection while minimizing the impact of continuous noise interference.
Solution Approach 2:
The noise detection part performs preliminary detection of high-frequency noise before the foreign object detection process. By identifying noise conditions in advance, the system can adjust its foreign object detection strategy accordingly, thereby improving detection reliability by avoiding periods of high noise interference.
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
Enhances the accuracy of detecting metallic foreign objects during wireless power transmission by isolating noise interference, ensuring reliable operation and preventing heat generation in foreign objects.
Implementation Method 1
a resonance circuit constituted of a coil and a capacitor... when a metallic foreign object enters between the magnetically coupled feeding coil and receiving coil, an eddy current flows in the metallic foreign object by magnetic flux
Implementation Method 2
an eddy current flows in the metallic foreign object by magnetic flux, resulting in heat generation in the metallic foreign object
Data Source
AI summary
An object of the present invention is to improve detection accuracy of a metallic foreign object between a feeding coil and a receiving coil during wireless power feeding. A wireless power transmitting device is a device that performs power transmission by wireless using an alternating magnetic field vibrating at a predetermined power transmission frequency and includes a feeding coil, an antenna coil, a capacitor that constitutes a resonance circuit RC together with the antenna coil, a noise detection part that detects noise vibrating at a frequency higher than the power transmission frequency, and a foreign object detection part 140 that detects the presence/absence of a metallic foreign object based on a change in voltage or current generated in the resonance circuit RC and a noise detection result from the noise detection part.