Wireless Power Transmitter Entity Detection via NFC Link
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Solution Overview
Problem
Current wireless power transfer systems, particularly those adhering to the Qi standard, face challenges in bidirectional communication, reliability, and foreign object detection, especially at high power levels, leading to potential interference and safety issues due to the reliance on a single inductive power signal for both power transfer and communication, and inaccurate estimation of power loss which can result in unintended heating of foreign objects.
Innovation Solution
Implementing a separate short-range communication link, such as NFC, independent of the power transfer signal to enhance communication reliability and safety by detecting potential entities through entity detection processes, ensuring accurate power transfer and preventing overheating of foreign objects by synchronizing communication with reduced power transfer intervals and using reference values to verify signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single inductive power signal is used for both power transfer and communication, then device complexity is reduced, but communication reliability deteriorates due to interference between power transfer operations
Solution Approach 1:
The patent divides the communication function into two separate channels: a bidirectional communication channel for reliable data exchange and a unidirectional power transfer channel for energy transmission. This segmentation allows each channel to be optimized independently, with the communication channel operating at frequencies and modulation schemes suitable for data integrity while the power channel handles energy transfer, thereby resolving the interference problem without excessive complexity.
Solution Approach 2:
The patent introduces a communication manager as an intermediary component that coordinates between the bidirectional communication channel and the power transfer operations. This manager processes communication signals, manages entity detection, and synchronizes operations to prevent interference, acting as a mediator that enables reliable communication while maintaining efficient power transfer.
2Ease of operation
If power transfer signal is used for communication, then ease of operation is improved, but measurement precision deteriorates due to inaccurate power loss estimation
Solution Approach 1:
The patent separates power loss measurement from communication functions by implementing a dedicated power loss manager that operates independently through the power transfer channel. This manager specifically monitors power transfer characteristics and calculates losses without being interfered with by communication signals, providing accurate measurements while maintaining operational simplicity through automated management.
Solution Approach 2:
The patent implements feedback mechanisms where the bidirectional communication channel continuously exchanges information about power transfer status, and the power loss manager uses this feedback to accurately calculate and adjust for power losses. This feedback loop ensures precise measurement by constantly monitoring and correcting for variations in the power transfer signal.
3Device complexity
If unidirectional communication from power receiver to power transmitter is implemented, then device complexity is reduced, but adaptability deteriorates due to lack of bidirectional communication
Solution Approach 1:
The patent implements a segmented communication architecture with a bidirectional communication channel for adaptive data exchange and a unidirectional power transfer channel for energy delivery. The bidirectional channel enables the power transmitter to receive device information and the power receiver to receive control signals, providing full adaptability while keeping the power transfer channel simple and dedicated.
Solution Approach 2:
The bidirectional communication channel serves multiple functions: exchanging device information, negotiating power transfer parameters, providing foreign object detection capabilities, and enabling entity detection. This multi-functional communication channel provides comprehensive adaptability without requiring separate dedicated systems for each function.
4Measurement precision
If foreign object detection is performed using power transfer signal, then measurement precision is improved, but reliability deteriorates due to interference and safety issues at high power levels
Solution Approach 1:
The patent separates foreign object detection into two independent mechanisms: entity detection through the bidirectional communication channel that identifies communicating devices, and foreign object detection through the power loss manager that monitors power transfer characteristics. This segmentation allows FOD to operate independently from communication interference while maintaining high detection accuracy through dedicated monitoring.
Solution Approach 2:
The power loss manager acts as an intermediary that specifically monitors power transfer characteristics to detect foreign objects. By focusing solely on power loss analysis through the power transfer channel, it provides accurate FOD without being interfered with by communication signals, while the communication manager handles entity identification separately.
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 improves communication reliability, reduces interference between power transfer operations, and enhances safety by accurately detecting foreign objects and preventing overheating, thereby ensuring a more robust and efficient wireless power transfer system.
Implementation Method 1
a power transmitter which includes a transmitter coil which is arranged to generate a power transfer signal which is propagated as a magnetic flux to a receiver coil
Implementation Method 2
a communication antenna which is arranged to transmit and/or receive an electromagnetic communication signal
Implementation Method 3
a monitor which is arranged to repeatedly determine a measured value for a characteristic of the communication signal when the power transmitter is in the power transfer phase
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A wireless power transfer system includes a power receiver (105) and a power transmitter (101) generating a wireless inductive power transfer signal for powering the power receiver (105) during a power transfer phase. An apparatus, often the power transmitter (101) comprises a first communication unit (305) communicating with a second communication unit of an entity using an electromagnetic communication signal. The entity may typically be the power receiver (105). The apparatus comprises a reference processor (307) for measuring and storing a reference value of a characteristic of the communication signal and a measurement unit (309) which repeatedly during the power transfer phase determines a measured value of the characteristic. A comparator (311) compares the measured values to the reference value and an initiator (313) triggers an entity detection process if the comparison indicates that a measured value and the reference value do not meet a similarity criterion. The entity detection process detect a presence of another entity.