Infrared Foreign Object Detection for Wireless EV Charging
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Solution Overview
Problem
Wireless charging systems for electric vehicles face challenges in safely and efficiently transferring power due to the risk of foreign objects heating up or causing hazards when exposed to electromagnetic fields, necessitating a method to detect such objects effectively.
Innovation Solution
An apparatus and method utilizing infrared sensors to generate thermal signals, time-differentiate them, and correlate these signals with varying magnetic fields to determine the presence of objects, thereby preventing potential hazards during power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless charging systems use electromagnetic fields to transfer power, then charging convenience is improved, but foreign objects may heat up causing safety hazards
Solution Approach 1:
The system performs preliminary detection of foreign objects before initiating full power transfer. The infrared sensor detects objects in the charging area, and the time-differentiated correlation analysis identifies foreign objects before they can heat up to hazardous temperatures, preventing safety hazards while maintaining charging convenience
Solution Approach 2:
The system continuously monitors thermal signals during wireless charging operation. By correlating time-differentiated thermal signals with magnetic field variations, the system provides real-time feedback on foreign object presence and heating status, allowing dynamic adjustment of power transfer to prevent hazardous temperature rise
2Reliability
If infrared sensors continuously monitor temperature to detect foreign objects, then safety is improved, but energy consumption increases
Solution Approach 1:
Instead of continuous monitoring, the system uses periodic thermal signal sampling synchronized with the wireless charging cycle. The time-differentiated correlation analysis processes thermal signals at specific intervals corresponding to magnetic field variations, achieving reliable foreign object detection while minimizing energy consumption by keeping the infrared sensor inactive during non-critical periods
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
Enables safe and efficient wireless charging by accurately detecting foreign objects before they reach hazardous temperatures, ensuring reliable and secure power transfer to electric vehicles.
Implementation Method 1
at least one infrared (IR) sensor configured to output a thermal signal indicative of a temperature of an area
Implementation Method 2
using electromagnetic fields may induce eddy currents in a well conducting (e.g., metallic or non-metallic) object located within the field, potentially causing the object to heat up
Implementation Method 3
using electromagnetic fields may induce eddy currents in a well conducting (e.g., metallic or non-metallic) object located within the field
Data Source
AI summary
Certain aspects of the present disclosure provide methods and apparatuses for detecting foreign objects via infrared sensing. One example apparatus generally includes at least one infrared (IR) sensor configured to output a thermal signal indicative of a temperature of an area. The apparatus further includes at least one time differentiator coupled to the at least one IR sensor, the at least one time-differentiator being configured to generate a time-differentiated thermal signal based on the thermal signal. The apparatus further includes at least one correlation unit configured to correlate the time-differentiated thermal signal to a varying exposure level magnetic field. The apparatus further includes a determining unit configured to determine whether an object is present in the area based on the correlation of the time-differentiated thermal signal to the varying exposure level magnetic field.