Wireless Power Coil Metal Detection via Periodic Switching
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Solution Overview
Problem
Existing wireless power transmission systems cannot effectively detect foreign bodies, particularly metal objects, and fail to quickly respond by stopping power transmission, which can lead to heating issues due to the magnetic field caused by power transmission.
Innovation Solution
A wireless power transmission system that includes a power transmission coil, a metal detecting device, and a controlling device to alternate between power transmission and metal detection periods, reducing power supply during metal detection to prevent heating and ensure safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power transmission is performed continuously to maintain high productivity, then power transmission efficiency is improved, but the ability to detect metal foreign bodies quickly deteriorates
Solution Approach 1:
The system alternates between power transmission periods and metal detection periods in a cyclic manner. During power transmission periods, full power is supplied to the transmission coil to maintain high efficiency. During metal detection periods, power supply is reduced or stopped to enable accurate detection of metal foreign bodies using the coil's magnetic field. This periodic switching resolves the contradiction by allowing both high productivity during transmission and reliable detection during dedicated detection intervals.
2Measurement precision
If power supply is reduced during metal detection to improve detection accuracy, then detection precision is improved, but power transmission efficiency deteriorates
Solution Approach 1:
The system implements periodic switching between full-power transmission mode and low-power detection mode. During detection periods, power supply to the transmission coil is reduced or stopped, creating optimal conditions for metal detection while accepting temporary reduction in transmission efficiency. During transmission periods, full power is restored to maintain high efficiency. This temporal separation allows both detection accuracy and transmission efficiency to be optimized in their respective phases.
3Reliability
If metal detection is performed frequently to improve safety, then detection reliability is improved, but the response time to stop power transmission deteriorates
Solution Approach 1:
The system performs metal detection during dedicated detection periods that occur regularly in the cyclic operation. By establishing a predetermined detection schedule, the system ensures that metal foreign bodies are detected reliably at regular intervals. The controlling device is pre-configured to immediately stop power transmission upon detection of metal, eliminating any delay in response. This preliminary structuring of detection intervals ensures both high detection reliability and rapid response capability.
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 accurate detection of metal foreign bodies and quick response to prevent heating, ensuring safe and efficient power transmission by controlling power supply based on metal detection.
Implementation Method 1
a wireless power transmission system configured to perform power transmission in a wireless manner by a method using an electromagnetic field
Implementation Method 2
a metal detecting device configured to perform metal detection for detecting whether or not there is metal in surroundings of the power transmission coil
Data Source
AI summary
A wireless power transmission system (10) can perform power transmission in a wireless manner. The wireless power transmission system is provided with: a power transmission coil (11); a power supplying device (14) configured to supply electric power to the power transmission coil; a metal detecting device (13) configured to perform metal detection for detecting whether or not there is metal in surroundings of the power transmission coil; and a controlling device (12) configured to provide a power transmission period which is a period for the power transmission and a metal detection period which is a period for the metal detection, and to control the power supplying device to supply electric power, which is lower than electric power supplied to the power transmission coil in the power transmission period, or not to supply electric power, to the power transmission coil in the metal detection period.