Wireless Power Transmitter RFID NFC Card Detection
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Solution Overview
Problem
Current wireless power transmission systems fail to detect RFID/NFC cards, leading to potential damage due to continuous exposure to strong magnetic fields and heat generation, as they lack the ability to differentiate these cards from foreign objects using existing detection methods.
Innovation Solution
Incorporating a communication/control unit in both wireless power transmitters and receivers to exchange packets for RFID/NFC detection, allowing the system to determine if the transmitter or receiver has the capability to detect these cards and temporarily halt power transfer to prevent damage during detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless power transmission is performed without RFID/NFC card detection, then power transfer efficiency is maintained, but RFID/NFC cards may be damaged due to continuous exposure to strong magnetic fields and heat generation
Solution Approach 1:
The system performs RFID/NFC card detection during the negotiation phase, which occurs before the power transfer phase begins. By detecting the presence of RFID/NFC cards in advance and preventing power transfer initiation, the system avoids exposing these cards to strong magnetic fields and heat generation, thereby ensuring their safety without requiring complex modifications to the power transmission mechanism
Solution Approach 2:
The patent introduces a communication/control unit that acts as an intermediary between the power transmission and detection functions. This unit exchanges packets with the power receiver to detect RFID/NFC cards, separating the detection function from the power transmission function. The communication unit mediates the interaction, allowing the system to detect RFID/NFC cards without requiring complex integration into the existing power transmission pathway
2Measurement precision
If FOD method is used for foreign object detection, then power loss detection is enabled, but RFID/NFC cards cannot be detected because they do not cause power loss and operate at different frequencies
Solution Approach 1:
The patent segments the detection process into distinct phases: the negotiation phase for RFID/NFC card detection and the power transfer phase for normal operation. During the negotiation phase, the system specifically detects RFID/NFC cards by exchanging detection packets, while during the power transfer phase, it monitors for foreign objects using power loss detection. This segmentation allows each detection method to operate optimally for its specific target without interference
Solution Approach 2:
The system dynamically adjusts its detection strategy based on the operational phase. During the negotiation phase, it uses RFID/NFC-specific detection protocols to identify cards operating at 13.56 MHz. During the power transfer phase, it switches to FOD methods for detecting foreign objects. This dynamic adaptation allows the system to maintain high detection accuracy across different scenarios and frequency ranges
3Productivity
If power transfer continues without detecting RFID/NFC cards, then continuous power transmission is maintained, but RFID/NFC cards are damaged due to heat generation and strong magnetic fields
Solution Approach 1:
The system performs RFID/NFC card detection during the negotiation phase, which occurs before the power transfer phase begins. By detecting the presence of RFID/NFC cards in advance and preventing power transfer initiation, the system avoids exposing these cards to strong magnetic fields and heat generation, thereby ensuring their safety without requiring complex modifications to the power transmission mechanism
Solution Approach 2:
The communication/control unit continuously exchanges packets with the power receiver, providing feedback about the presence of RFID/NFC cards. This feedback mechanism allows the system to monitor the charging area throughout the power transfer process and immediately halt power transmission if an RFID/NFC card is detected, preventing heat generation and magnetic field damage while maintaining overall power transmission 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 safe detection of RFID/NFC cards, preventing damage and ensuring stable wireless power transmission by allowing the system to recognize and respond to their presence, thereby avoiding overheating and financial losses.
Implementation Method 1
In the electromagnetic induction method, a power transmission unit generates a magnetic field through a power transmission coil (i.e., a primary coil), and a power reception coil (i.e., a secondary coil) is placed at the location where an electric current may be induced so that power is transferred.
Implementation Method 2
a power reception coil (i.e., a secondary coil) is placed at the location where an electric current may be induced so that power is transferred
Implementation Method 3
In the resonant method, energy is transmitted using a resonant phenomenon between the transmission coil and the reception coil. In this case, a system is configured so that the primary coil and the secondary coil have the same resonant frequency, and resonant mode energy coupling between the transmission and reception coils is used.
Data Source
AI summary
The present invention relates to a wireless power transmitter and method for detecting a RFID/NFC card. Disclosed in the present application is a wireless power receiver comprising: a power pickup unit configured to receive, in a power transfer phase, wireless power generated by magnetic coupling from a wireless power transmitter; and a communications/control unit configured to transfer, in a negotiation phase, a first end-of-power-transfer (EPT) packet to the wireless power transmitter for detecting an RFID/NFC card, and to detect the RFID/NFC card during a re-ping time secured on the basis of the first EPT packet, wherein the first EPT packet instructs requesting the removal of a power signal for a predetermined time. As the process for detecting communication cards, such as RFID or NFC, between the wireless power transmitter and receiver is clearly defined, such RFID/NFC cards can be protected against getting destroyed by the wireless power, and a stable wireless power transfer can be achieved.