Wireless Power Charging Foreign Object Detection via Relay Coupling
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Solution Overview
Problem
Commercially available wireless power charging systems are limited to a maximum charging distance of 10 millimeters and require complex and costly installation, which is not aesthetically pleasing and poses hazards, while also being insufficient for charging handheld devices requiring more than 15 watts.
Innovation Solution
A method for foreign object detection in a system with a relay and transmitter separated by a medium, using a controller to determine power consumption, power loss, and coupling factor to detect foreign objects and adjust operational frequency for efficient charging, allowing for increased charging distance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If wireless power charging systems are deployed in public facilities with decorative appearance requirements, then aesthetic appearance is improved, but installation complexity and cost increase due to wiring requirements and surface drilling
Solution Approach 1:
The system divides the power transfer function into two separate components: a transmitter unit that can be installed in the furniture surface and a receiver unit that attaches to the device. This segmentation allows the transmitter to be hidden within the furniture (maintaining aesthetics) while the receiver handles the power reception externally, eliminating the need for complex wiring and surface drilling.
Solution Approach 2:
The patent introduces an intermediary magnetic coupling mechanism that enables wireless power transfer through the furniture surface without requiring physical wiring or holes. The transmitter and receiver units communicate and transfer power through magnetic fields that penetrate the furniture material, serving as an intermediary that eliminates direct electrical connections while maintaining aesthetic appearance.
2Ease of operation
If the charging distance between transmitter and receiver is increased beyond 10 millimeters, then ease of operation is improved, but power transfer efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts the operating frequency of the transmitter and receiver units to optimize power transfer efficiency at varying distances. The controller monitors the coupling factor between units and automatically tunes the resonant frequency to maintain maximum efficiency even when the distance between transmitter and receiver exceeds the traditional 10mm limit.
Solution Approach 2:
The patent changes the operating parameters of the wireless power system by using adjustable frequency ranges and adaptive power levels. By varying the frequency and power output based on detected distance and coupling conditions, the system maintains efficient power transfer over extended distances while adapting to different operational scenarios.
3Productivity
If power is increased to charge devices requiring more than 15 watts, then productivity is improved, but safety risks increase due to foreign object heating
Solution Approach 1:
The system implements continuous feedback monitoring through the controller that tracks power transfer efficiency, coupling factor, and temperature conditions. When a foreign object is detected or abnormal heating is identified, the controller automatically adjusts or terminates power delivery to prevent harmful effects, enabling safe operation at higher power levels up to 15 watts and beyond.
Solution Approach 2:
The patent applies partial power delivery strategies where the transmitter provides only the necessary power level based on real-time conditions. Instead of always operating at maximum capacity, the system delivers optimized power levels that prevent foreign object heating while still meeting the charging requirements of high-power devices, using adaptive control to balance safety and productivity.
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 wireless power charging beyond the traditional 10 millimeter limit, ensuring safety by detecting foreign objects and adjusting power transfer, thus enhancing user experience and reducing installation complexity and costs.
Implementation Method 1
a transmitter having a controller configured to inductively transmit to the relay the power for charging the device
Implementation Method 2
a relay adapted to inductively transfer power for charging a device
Data Source
AI summary
According to a first aspect of the present disclosed subject matter, a method for foreign object detection in a system having a relay adapted to inductively transfer power for charging a device and a transmitter having a controller configured to inductively transmit to the relay the power for charging the device, wherein the transmitter and the relay are separated by a medium, wherein the controller is capable of communicating with the device, the method comprising operations by the controller: determining power consumed by the transmitter; determining power loss on the transmitter according to continuous measurements of AC output current; obtaining coupling factor between the transmitter and the relay; determining power loss on the relay based on continuous measurements of AC output current and coupling factor; subtracting from the power consumed by the transmitter the power loss on the transmitter and power loss on the relay; obtaining from the device consumed power of the device; comparing a result of the subtracting to the consumed power of the device; determining foreign object presence.