Foreign Object Detection for Wireless Energy Transfer Resonators
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Solution Overview
Problem
Wireless energy transfer systems face inefficiencies and safety concerns due to foreign objects, such as metallic items and animals, in the vicinity of the source resonator, which can reduce energy transfer efficiency and cause localized heating.
Innovation Solution
A system combining a visible light camera and a multiple zone temperature sensor to detect foreign objects by creating intensity, hue, and saturation maps, which intersect with thermal maps to identify and control the electric current provided to the source resonator, preventing or modifying system operation when a foreign object is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single detection method (e.g., temperature sensor only) is used to detect foreign objects, then the device complexity is reduced, but the measurement precision and reliability of foreign object detection deteriorates
Solution Approach 1:
The patent combines multiple detection methods (visible light camera, infrared camera, and temperature sensor) into a single integrated detection system. The controller fuses data from all three sensors to detect foreign objects, leveraging the strengths of each sensor type to achieve high detection precision while maintaining a unified system architecture.
Solution Approach 2:
The controller acts as an intermediary that receives and processes data from multiple independent sensors (camera, infrared sensor, temperature sensor). It integrates these separate detection streams and makes the final determination of foreign object presence, coordinating the information from different sensing modalities.
2Reliability
If multiple detection methods are combined to improve foreign object detection accuracy, then the measurement precision and reliability improve, but the device complexity increases
Solution Approach 1:
The patent merges multiple detection methods (visible light camera, infrared camera, and temperature sensor) into a single integrated detection system. The controller fuses data from all three sensors to detect foreign objects, leveraging the strengths of each sensor type to achieve high detection precision while maintaining a unified system architecture.
Solution Approach 2:
The detection system is designed with multi-functionality, where the controller can process data from different sensor types (optical, thermal, temperature) and perform multiple detection tasks. This universal approach allows the system to reliably detect various types of foreign objects using a single integrated platform.
3Adaptability or versatility
If the ground clearance space between source resonator and capture resonator is made large to accommodate vehicle clearance, then the adaptability to different vehicles is improved, but the harmful factors from foreign objects (energy loss and heating) worsen
Solution Approach 1:
The system performs preliminary detection of foreign objects in the space between the source and capture resonators before initiating energy transfer. By detecting metallic foreign objects, animals, or other objects in advance, the system can prevent or modify operation to avoid energy loss and heating issues that would occur with a large ground clearance space.
Solution Approach 2:
The detection system provides feedback about the presence of foreign objects in the resonator space. Based on this feedback, the wireless energy transfer system can adjust its operation - reducing power or shutting down when foreign objects are detected - thereby maintaining adaptability to different vehicles while preventing the harmful effects of foreign object heating and energy loss.
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
Effectively detects foreign objects before and during energy transfer, preventing inefficiencies and safety hazards by inhibiting or reducing energy transfer when foreign objects are present, and distinguishing between biologic and metallic objects based on thermal characteristics.
Implementation Method 1
a visible light camera mounted so as to have a camera field of view that includes the source resonator. The camera is configured to output image data indicative of visible light intensity detected by pixels in the camera
Implementation Method 2
a multiple zone temperature sensor mounted so as to have a sensor field of view that includes the source resonator and is similar to the camera field of view. The sensor is configured to output thermal data indicative of a zone temperature for each of the multiple zones
Implementation Method 3
a first resonator structure (source resonator) that includes a coil configured for transferring magnetic energy and a spaced apart second resonator structure (capture resonator) that also includes a coil configured for receiving the wirelessly transmitted magnetic energy
Implementation Method 4
Metallic foreign objects such as these in the vicinity of the source resonator may reduce the energy transfer efficiency of the resonators and may cause undesirable localized heating due to inductive heating of the foreign object
Data Source
AI summary
A system and method to detect a foreign object proximate to a source resonator that is part of a wireless energy transfer system. The wireless energy transfer system may be one used to wirelessly charge the batteries of an electric vehicle. Data from a visible light camera and a multiple zone temperature sensor are combined or fused to determine whether a foreign object, such a metallic object or an animal, is in the vicinity of, or in close proximity to, a source resonator. The system controls an electric current provided to the source resonator based on whether a foreign object is detected to reduce or inhibit energy emitted by the source resonator. The visible light camera may be a monochrome or color camera and the temperature sensor may be an infrared camera or a thermopile array.