Wireless Power Receiver Foreign Object Detection via Dual Q-Factor Reference
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Solution Overview
Problem
Current wireless power transfer systems face challenges in accurately detecting foreign objects between the transmitter and receiver, particularly when the wireless power receiver has a low quality factor, which can lead to false negatives in foreign object detection.
Innovation Solution
The implementation of a method where the wireless power receiver transmits information about first and second reference quality factors measured at specific frequencies to the transmitter, allowing the system to detect foreign objects by comparing these values, thereby enhancing the accuracy of foreign object detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wireless power receiver has a low quality factor, then power transfer efficiency is reduced, but foreign object detection accuracy deteriorates leading to false negatives
Solution Approach 1:
The patent segments the quality factor measurement into multiple discrete frequency points (first frequency f1(ref) and second frequency f2(ref)) rather than using a single measurement. By dividing the measurement into multiple segments at different frequencies, the system can detect foreign objects more accurately even when the overall quality factor is low, as each frequency segment provides independent detection data that reduces false negatives.
Solution Approach 2:
The patent adds a frequency dimension to the quality factor measurement by performing measurements at multiple distinct frequencies (f1(ref) and f2(ref))). This dimensional expansion transforms a single scalar quality factor measurement into a multi-dimensional measurement space, enabling more robust foreign object detection that is not dependent on a single frequency point and works effectively even when the receiver has low quality factor.
2Reliability
If multiple reference quality factor measurements are performed at different frequencies, then foreign object detection accuracy is improved, but communication data requirements increase
Solution Approach 1:
The patent extracts only the essential measurement data (quality factor values at first frequency f1(ref) and second frequency f2(ref)), and resonance frequency information) needed for foreign object detection, transmitting these specific extracted parameters to the wireless power transmitter. This selective extraction avoids transmitting redundant or unnecessary data, thereby improving detection accuracy while minimizing communication data requirements and preventing information loss.
3Measurement precision
If quality factor measurements are performed at multiple frequencies, then differentiation between foreign object presence and absence is improved, but measurement time increases
Solution Approach 1:
The patent performs quality factor measurements at multiple frequency points (f1(ref) and f2(ref)) during the negotiation phase before the actual power transfer begins. This preliminary action allows the system to complete all necessary measurements and detect foreign objects in advance, so that when power transfer starts, the detection is already complete. This approach improves detection precision while minimizing time loss during the critical power transfer phase.
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
This approach enables more accurate detection of foreign objects, even in scenarios where the wireless power receiver has a low quality factor, by using multiple reference quality and resonance frequency measurements to differentiate between the presence and absence of foreign objects.
Implementation Method 1
a power pickup circuit for receiving a wireless power from a wireless power transmitter by magnetic coupling with the wireless power transmitter
Implementation Method 2
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
A wireless power reception apparatus according to an embodiment of the present specification comprises: a power pickup circuit for receiving, by magnetic coupling to a wireless power transmission apparatus, wireless power from the wireless power transmission apparatus; and a communication/control circuit for communicating with the wireless power transmission apparatus and controlling the received wireless power, wherein the communication/control circuit transmits, before entering a power transmission phase, to the wireless power transmission apparatus, information regarding a first reference quality factor Qt1′(ref) measured at a first frequency f1(ref) and information regarding a second reference quality factor Qt2′(ref) measured at a second frequency f2(ref).