Wireless Power Coil Slot Q-Factor for Foreign Object Detection
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Solution Overview
Problem
Existing wireless power transfer systems face challenges in determining the presence of foreign objects during power transmission, which can lead to inefficiencies and potential damage to devices.
Innovation Solution
A method and apparatus for calculating the slot quality factor during wireless power transfer, allowing for rapid detection of foreign object insertion by identifying the point where coil voltage is maximum and current is zero, enabling quick determination of foreign object presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If foreign object detection is performed during wireless power transfer, then device safety is improved, but detection speed and accuracy deteriorate due to ongoing power transmission interference
Solution Approach 1:
The patent segments the power transfer cycle into distinct phases: a power transfer phase and a measurement phase. During the measurement phase, power transmission is temporarily suspended to allow accurate quality factor measurement for foreign object detection. This temporal segmentation eliminates interference between power transmission and detection operations, enabling both safety and detection accuracy to be achieved.
Solution Approach 2:
The patent implements periodic quality factor measurements at predetermined intervals during the power transfer process. By periodically pausing power transmission to perform measurements, the system maintains continuous monitoring capability while minimizing interference. This periodic approach allows the system to balance ongoing power delivery with accurate foreign object detection.
2Reliability
If quality factor measurement is performed during power transfer, then foreign object detection capability is improved, but power transfer efficiency deteriorates due to measurement interruptions
Solution Approach 1:
The patent applies partial action by performing quality factor measurements at selective intervals rather than continuously. Measurements are conducted at predetermined times when power transfer is temporarily paused, rather than attempting constant monitoring. This partial measurement approach minimizes the impact on power transfer efficiency while maintaining sufficient detection capability to ensure safety.
3Speed
If continuous monitoring is implemented during wireless power transfer, then detection speed is improved, but energy consumption and system complexity increase
Solution Approach 1:
The patent implements periodic monitoring at predetermined intervals during the power transfer process. Rather than continuous monitoring, the system pauses power transfer at specific intervals to perform quality factor measurements. This periodic approach maintains detection speed by ensuring regular monitoring while significantly reducing energy consumption compared to continuous operation.
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 rapid detection of foreign objects during wireless power transfer, ensuring efficient and safe power transmission by preventing damage to devices.
Implementation Method 1
The magnetic induction method corresponds to a method transmitting power by using electric currents that are induced to the coil of the receiver by a magnetic field, which is generated from a coil battery cell of the transmitter, in accordance with an electromagnetic coupling between a transmitting coil and a receiving coil.
Implementation Method 2
in accordance with an electromagnetic coupling between a transmitting coil and a receiving coil
Implementation Method 3
The magnetic resonance method is similar to the magnetic induction method in that is uses a magnetic field. However, the magnetic resonance method is different from the magnetic induction method in that energy is transmitted due to a concentration of magnetic fields on both a transmitting end and a receiving end, which is caused by the generated resonance.
Data Source
AI summary
The present disclosure provides a method for transmitting wireless power performed by a wireless power transmitter in a wireless power transmission system, and an apparatus using same, the method comprising: receiving information for detecting whether a foreign object (FO) exists from a wireless power receiver; detecting whether the FO exists before transmission of wireless power on the basis of the information; transmitting the wireless power to the wireless power receiver on the basis of detecting that the FO does not exist; and calculating a slot quality factor on a slot while transmitting the wireless power, wherein the slot quality factor is a quality factor used to determine whether an FO has been inserted while transmitting the wireless power, and a starting point of the slot is a point at which a voltage value of a coil in a wireless power transmitter is the maximum value and a current value of the coil is 0.