Wireless Inductive Power Transfer Synchronization
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Solution Overview
Problem
The Qi wireless power transfer system lacks bidirectional communication support, leading to interference and reliability issues due to the use of the power transfer signal for both power transmission and communication, especially in scenarios with varying loads and multiple devices.
Innovation Solution
A wireless power transfer system that employs a separate short-range communication channel using NFC, synchronized with the power transfer signal's time frame, allowing communication during reduced power intervals to avoid interference and ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the power transfer signal is used for both power transmission and communication, then the system complexity is reduced, but communication reliability deteriorates due to interference
Solution Approach 1:
The patent segments the power transfer signal into distinct time intervals: power transfer time intervals for power transmission and reduced power time intervals for communication. This temporal segmentation allows separate optimization of power transfer efficiency and communication reliability without mutual interference, resolving the contradiction between system simplicity and communication reliability.
Solution Approach 2:
The system implements periodic alternation between power transfer phases and communication phases within a structured time frame. This periodic action ensures that communication occurs during reduced power intervals when interference is minimized, thereby maintaining communication reliability while preserving overall system functionality.
2Productivity
If power transfer and communication occur simultaneously, then data transmission speed is improved, but interference increases leading to operation errors
Solution Approach 1:
The patent implements periodic time-division multiplexing where communication is restricted to reduced power time intervals within each power transfer time frame. This periodic structure enables bidirectional communication with sufficient data rates while eliminating continuous interference, as the power transfer signal is reduced or absent during communication phases.
Solution Approach 2:
The patent introduces a synchronizer as an intermediary component that coordinates between the power transfer unit and communication unit. The synchronizer ensures communication operations are timed to occur during reduced power intervals, acting as a mediator that prevents interference while maintaining efficient data transmission.
3Productivity
If communication is performed during high power intervals, then communication efficiency is improved, but safety deteriorates due to risk of unintended heating
Solution Approach 1:
The system periodically switches between power transfer intervals and reduced power intervals, restricting communication to the reduced power phases. This periodic action ensures communication efficiency is maintained during low-interference windows while eliminating the safety hazard of unintended heating that would occur if communication happened during high power intervals.
4Reliability
If a separate communication channel is introduced, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the existing power transfer system into distinct functional phases (power transfer phases and communication phases) using time-division multiplexing. This segmentation creates a separate communication channel without adding physically separate hardware channels, thereby improving communication reliability while minimizing increases in device complexity.
Solution Approach 2:
The power transfer signal serves dual purposes: power transmission during power transfer intervals and communication carrier during reduced power intervals. This multi-functionality allows a single hardware infrastructure to support both power transfer and reliable communication, avoiding the need for entirely separate communication hardware and thus limiting complexity increases.
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 improved communication reliability, reduced interference, and safer operation by separating power transfer and communication functions, supporting bidirectional communication and higher data rates while maintaining efficient power transfer.
Implementation Method 1
a power transfer inductor configured to transfer of the power transfer signal
Implementation Method 2
a communication antenna arranged for short range communication
Data Source
Figure 1
Figure 2
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AI summary
A wireless power transfer system includes a power transmitter (101) arranged to provide a power transfer to a power receiver (105) via a wireless inductive power transfer signal where the power transfer signal is provided in a power time interval of a repeating power transfer signal time frame. The time frame furthermore comprises a reduced power time interval. An apparatus (typically being the power receiver (105) or the power transmitter (101)) comprises a short range communication unit (305, 405) arranged to communicate data messages with a second entity (which is the complementary unit, i.e. either the power transmitter (101)) or the power receiver (105)) using short range communication. The short range communication has a range not exceeding 20 cm. The apparatus further comprises a synchronization unit (309, 409) arranged to synchronize the short range communication to the power transfer signal time frame such that short range communication is restricted to the reduced power time intervals. The communication may specifically be NFC communication.