Contactless Charger Foreign Body Detection via Optical Scanning
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Solution Overview
Problem
Existing contactless charging systems face safety issues due to the inability to accurately detect metallic foreign bodies above the power transmission coil without sensors near the coil, which can lead to overheating and potential fires.
Innovation Solution
A contactless charging device with a power transmission part featuring a plurality of projections and a beam emission system that uses light to detect foreign bodies, allowing for accurate detection without sensors near the power transmission coil, and controls power supply accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermistor is disposed near the power transmission coil to detect foreign bodies, then foreign body detection capability is improved, but the thermistor may be damaged by magnetic flux or heated by induced heat
Solution Approach 1:
The patent extracts the temperature sensor from the high-temperature, high-magnetic flux environment near the power transmission coil and places it in a safe location. Instead of measuring temperature directly near the coil, the system uses a camera to detect foreign bodies from a distance, eliminating the risk of sensor damage while maintaining detection capability.
Solution Approach 2:
The patent introduces a camera as an intermediary detection device that bridges the gap between the need for foreign body detection and the need to avoid sensor damage. The camera captures images of the charging surface, and image processing algorithms identify foreign bodies without requiring physical contact with the high-temperature, high-magnetic flux environment.
2Device complexity
If a thermistor is used to detect foreign bodies by temperature difference, then detection method is simple, but detection accuracy is insufficient and detection is delayed until threshold is reached
Solution Approach 1:
The patent replaces the thermal detection mechanism with an optical detection system. Instead of using a thermistor to measure temperature differences, the system uses a camera to capture visual information and identify foreign bodies through image processing, enabling earlier and more accurate detection.
Solution Approach 2:
The patent performs foreign body detection before power transmission begins by capturing images of the charging surface. This preliminary detection allows the system to identify foreign bodies in advance and prevent power transmission that could cause overheating, rather than waiting for temperature thresholds to be reached during operation.
3Reliability
If no sensor is disposed near the power transmission coil, then sensor safety is improved, but foreign body detection capability deteriorates
Solution Approach 1:
The patent introduces a camera as an intermediary detection device that enables foreign body detection without placing sensors near the power transmission coil. The camera captures images of the charging surface, and image processing algorithms identify foreign bodies, providing detection capability while maintaining sensor safety.
Solution Approach 2:
The patent creates an optical copy (image) of the charging surface using a camera. This visual copy allows the system to analyze the presence of foreign bodies without requiring physical sensors in the hazardous environment. The image data serves as a safe representation that enables detection while keeping sensors at a safe distance.
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 accurate detection of foreign bodies above the power transmission coil, preventing overheating and potential fires by controlling power supply based on light detection, thus ensuring safe wireless power transmission.
Implementation Method 1
a beam emission part emitting light that progresses over the upper surface of the power transmission part
Implementation Method 2
One example of such a device for wirelessly supplying electrical power according to this type of contactless method employs electromagnetic induction
Data Source
AI summary
A plurality of projections is arranged in a matrix on the upper surface of the housing of a contactless charging unit (110). When supplying power wirelessly to an onboard power reception device, a beam emission unit in a beam reception and emission unit (120) emits a laser beam progressing along the upper surface of a power transmission unit (170) to scan the upper part of the entire upper surface of the power transmission unit (170). When receiving a reflected beam, the beam reception unit in the beam reception and emission unit (120) sends the results of beam reception to a determination unit. The determination unit determines the presence or absence of a foreign substance supported on at least one projection existing on the upper surface of the contactless charging unit (110) on the basis of the results of beam reception. Subsequently, when a foreign substance is present on the upper surface of the contactless charging unit (110), the control unit generates a supply control command indicating that no power is to be supplied to the onboard power reception device and sends the command to a supply unit. This will enable wireless power supply using the contactless system without any problem in terms of safety.