Vertical Wireless Charger Foreign Object Detection via Thermal Sensing
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Solution Overview
Problem
Vertical type wireless chargers face challenges in detecting metal foreign objects, which can generate heat and cause instability during charging due to the dead angle design, leading to potential overheating and increased complexity and cost with existing detection methods.
Innovation Solution
A wireless charging device with a cup-shaped holder, a power transmission coil, a thermal sensor at the bottom, a controller to monitor temperature and alert the user, and an optional cooler to manage heat, allowing for detection and prevention of foreign object heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a vertical type holder structure is used to reduce installation space, then the installation space is reduced, but the user cannot easily detect metal foreign objects due to dead angles
Solution Approach 1:
The patent replaces complex mechanical detection systems (multiple Hall elements, IC tags) with a simple thermal sensing system. The thermal sensor detects heat generation from metal foreign objects through conduction, providing effective detection without requiring complex mechanical or electromagnetic detection mechanisms in the holder structure.
Solution Approach 2:
The patent introduces thermal conduction as an intermediary mechanism to detect foreign objects. Instead of directly detecting the presence of metal objects, the system detects the heat they generate through thermal conduction, using heat as a mediator signal that can be sensed by the thermal sensor positioned at the holder bottom.
2Reliability
If multiple Hall elements and IC tags are used to detect foreign objects, then detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the detection function from complex electromagnetic sensing components (Hall elements, IC tags) and implements it through a simple thermal sensing approach. By taking out only the essential detection capability and implementing it through thermal conduction sensing, the system achieves reliable foreign object detection with minimal complexity.
Solution Approach 2:
The patent changes the detection parameter from electromagnetic field characteristics (used in Hall element and IC tag systems) to thermal characteristics. By monitoring temperature changes and heat generation patterns, the system achieves foreign object detection using a different physical parameter that can be measured with simple, low-cost thermal sensors.
3Difficulty of detecting and measuring
If thermal sensor at bottom part is used to detect foreign objects, then detection capability is improved, but false detection of power receiving device heat generation may occur
Solution Approach 1:
The patent implements feedback control where the controller continuously monitors thermal sensor data and adjusts power supply accordingly. When abnormal heat generation is detected, the system provides feedback by stopping power supply, preventing false detection issues and ensuring reliable operation. This closed-loop control distinguishes between normal device heating and abnormal foreign object heating.
Solution Approach 2:
The patent performs preliminary thermal sensing before charging issues arise and implements preventive power supply control. By continuously monitoring temperature trends and detecting abnormal heat generation patterns early, the system can stop power supply before false detection becomes a problem, preventing both overheating and detection errors.
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 and alerts users to metal foreign objects, preventing overheating and ensuring safe charging by controlling power supply and potentially cooling the object, thus enhancing safety and simplifying the device structure.
Implementation Method 1
a thermal sensor disposed at the bottom part of the holder for sensing heat in the holder
Implementation Method 2
a power transmission coil disposed at the side part of the holder for performing wireless charging for the power receiving device
Data Source
AI summary
To realize a vertical type wireless charging device capable of detecting a metal foreign object. The wireless charging device comprises a holder, a power transmission coil, a thermal sensor, a controller, and a warning device. The power transmission coil is disposed outside the side part of the holder. The thermal sensor is disposed at the bottom part of the holder. When the temperature rising rate is not less than 20° C. per five minutes, the controller judges that a metal foreign object exists between the power transmission coil and the electronic device, and the foreign object generates unusual heat. The controller stops wireless charging from the power transmission coil to the electronic device. The controller starts the warning device to alert the user that a foreign object is mixed in the holder and generates unusual heat.