Wireless Power Foreign Object Detection via Spatial Magnetic Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless power transfer systems face challenges in accurately detecting foreign objects due to uncertainties in current operating conditions, such as unknown magnetic and electrical properties of device metals and spatial alignment issues, leading to suboptimal detection performance, especially at higher power levels and with larger coils, which can result in false or missed detections.
Innovation Solution
A power transmitter system with spatially distributed detection coils and a test signal coil generates a magnetic test signal, producing measurement values that are compared to a reference spatial distribution to detect foreign objects, allowing for geometric alignment and improved detection accuracy by differentiating between friendly and foreign metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power transmission is increased to higher power levels, then power transfer capability is improved, but foreign object detection accuracy deteriorates due to uncertainties in magnetic and electrical properties
Solution Approach 1:
The detection system is divided into multiple spatially distributed detection coils that independently measure magnetic field characteristics at different locations. This segmentation allows the system to create a detailed spatial map of the magnetic field, improving detection accuracy even at higher power levels where traditional single-point detection fails.
Solution Approach 2:
The patent transitions from traditional single-point or simple power-based detection to a three-dimensional spatial distribution measurement approach. By measuring magnetic field characteristics across multiple spatial dimensions with distributed coils, the system can accurately detect foreign objects regardless of power level variations or uncertainties in magnetic properties.
2Power
If larger coils are used to increase power transfer, then power transmission is improved, but detection performance deteriorates due to spatial alignment uncertainties
Solution Approach 1:
Instead of using a single large coil that creates spatial alignment uncertainties, the system segments the detection function into multiple smaller distributed coils. Each coil provides localized measurement, eliminating the need for precise spatial alignment while maintaining high power transmission capability through the larger overall coil structure.
Solution Approach 2:
The system changes the detection parameter from simple power measurement or single-point field measurement to spatial distribution measurement. By analyzing the spatial pattern of magnetic field measurements across multiple coils rather than relying on absolute alignment, the system achieves robust detection performance independent of spatial positioning uncertainties.
3Device complexity
If traditional foreign object detection methods are used, then system complexity is reduced, but detection reliability deteriorates leading to false or missed detections
Solution Approach 1:
The detection function is segmented into multiple independent measurement channels, each using a separate detection coil. This segmentation provides redundant measurement paths that cross-validate each other, significantly improving detection reliability and reducing false positives while the modular architecture keeps system complexity manageable.
Solution Approach 2:
The system implements feedback by comparing measured spatial distribution patterns against expected patterns. The processor analyzes deviations from expected magnetic field distributions and uses this feedback to reliably detect foreign objects, reducing false detections while maintaining a relatively simple overall system architecture through intelligent signal processing.
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 foreign object detection accuracy, reduces false and missed detections, and provides flexibility in power receiver placement, ensuring reliable power transfer operations even at higher power levels.
Implementation Method 1
A power transmitter system with spatially distributed detection coils and a test signal coil generates a magnetic test signal, producing measurement values
Implementation Method 2
a power output circuit comprising a transmit power coil for generating the wireless inductive power transfer signal
Implementation Method 3
the magnetic flux generated by the transmitter coil will introduce eddy currents in the metal objects which will cause the objects to heat up
Data Source
AI summary
A wireless power transfer system includes a power receiver (105) receiving a power transfer from a power transmitter (101) via a wireless inductive power transfer signal. The power transmitter (101) comprises a transmit power coil (103) generating the power transfer signal. A test signal coil (209) coupled to a test signal generator (211) generates a magnetic test signal. A plurality of spatially distributed detection coils (213) is coupled to measurement unit (215) generating a set of measurement values reflecting signals induced in the detection coils (213) by the magnetic test signal. A processor (217) determines a measurement spatial distribution of the measurement value where the spatial distribution reflects positions of the detection coils (213). A foreign object detector (219) detects a presence of a foreign object in response to a comparison of the measurement spatial distribution to a reference spatial distribution. The foreign object detector (219) is arranged to determine the reference spatial distribution in response to data received from the power receiving device (105).