Wireless Power Transfer Backchannel Using Correlated Chip Sequences
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Solution Overview
Problem
Existing wireless power transfer systems face challenges such as increased electromagnetic interference, acoustic noise, and reduced backwards compatibility due to load modulation, especially at higher power levels.
Innovation Solution
The system employs a power transmitter with a first communicator that receives symbols by load modulation of the power transfer signal, using chip sequences synchronized with the power transfer signal to improve communication and reduce noise, while also allowing for backwards compatibility through a second communicator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If load modulation is used for communication in wireless power transfer, then communication functionality is enabled, but electromagnetic interference and acoustic noise increase
Solution Approach 1:
The communication signal is segmented into chip sequences that are spread over multiple cycles of the power transfer signal. This segmentation allows the communication information to be distributed across time, reducing the peak electromagnetic interference and acoustic noise generated by load modulation while maintaining communication reliability through correlation processing.
2Reliability
If chip sequences synchronized with power transfer signal are used, then communication reliability is improved and noise is reduced, but system complexity increases
Solution Approach 1:
The chip sequences are pre-synchronized with the power transfer signal frequency and phase. This preliminary synchronization eliminates the need for complex real-time frequency and phase detection during communication processing. The receiver can directly correlate the received signal with the known synchronized chip sequences, significantly reducing processing complexity while maintaining high communication reliability.
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 enhances communication reliability, reduces electromagnetic and acoustic noise, and improves power transfer efficiency, while maintaining backwards compatibility and allowing for easy modification of existing systems.
Implementation Method 1
wireless power transfer at higher power levels... power is inductively transferred from a transmitter coil in a power transmitter device to a receiver coil
Implementation Method 2
a receiver coil in the individual devices... power is inductively transferred from a transmitter coil to a receiver coil
Data Source
AI summary
A power transfer system comprises a power transmitter (101) wirelessly providing power to a power receiver (105) via an inductive power transfer signal. Communication from power receiver (105) to the power transmitter (101) is by load modulation using the power transfer signal. The communication uses load modulation where each symbol is represented by a chip sequence being a sequence of modulation load values. The power transmitter (101) comprises a first communicator (207) which correlates a chip sequence received from the power receiver with a set of reference chip sequences being linked to data symbol values and determines the data symbol as the data symbol linked to a reference chip sequence for which the highest correlation with the first chip sequence is determined.