Wireless Power Transfer Load Modulation With DSSS Chip Sequences
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Solution Overview
Problem
Existing wireless power transfer systems face challenges such as electromagnetic interference, acoustic noise, and reduced compatibility due to load modulation, especially at higher power levels, which complicates communication and increases complexity.
Innovation Solution
A wireless power transfer system using chip sequences for load modulation, where each data symbol is represented by a series of load changes, allowing for improved communication reliability and reduced electromagnetic interference through Direct Sequence Spread Spectrum (DSSS) communication.
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 achieved, but electromagnetic interference and acoustic noise increase
Solution Approach 1:
The communication signal is segmented into multiple chips that collectively represent each data symbol. This segmentation into chip sequences allows the communication to be embedded within the power transfer signal without requiring separate communication channels, thereby reducing electromagnetic interference while maintaining communication reliability
Solution Approach 2:
The communication function is merged with the power transfer function by modulating the load on the power receiver during power transfer. The load modulation creates variations in the power transfer signal that encode communication data, combining both functions into a single signal path and reducing the need for separate communication circuits that would increase interference
2Adaptability or versatility
If load modulation is used for communication, then bidirectional communication is achieved, but device complexity increases
Solution Approach 1:
The power transfer signal serves multiple functions simultaneously: it transfers power and carries communication data in both directions. The load modulation technique allows the power receiver to communicate status and control information back to the power transmitter using the same signal path, making the system multi-functional without requiring separate dedicated communication hardware
Solution Approach 2:
The power transfer signal itself is used to carry communication information. The load variations on the power receiver naturally modulate the reflected power signal, which the power transmitter can detect and decode. This self-service approach uses the existing power transfer infrastructure for communication without requiring additional complex communication circuitry
3Power
If higher power levels are used for wireless power transfer, then power delivery capability is improved, but communication reliability and system stability deteriorate
Solution Approach 1:
The communication is implemented through periodic load modulation on the power receiver, creating regular patterns of load variations that encode data symbols. These periodic modulations are superimposed on the high-power transfer signal, allowing reliable detection through correlation techniques even at higher power levels where noise and interference are more significant
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
The system achieves reduced electromagnetic and acoustic noise, improved compatibility, and enhanced communication reliability with lower computational complexity, facilitating efficient power transfer at higher power levels.
Implementation Method 1
a transmitter coil arranged to generate an inductive power transfer signal
Implementation Method 2
a receiver coil arranged to extract power from the power transfer signal
Data Source
AI summary
A power transmitter (101) provides power to a power receiver (105) via an inductive power transfer signal which is also used by the power receiver (105) for communication by load modulation. The power transmitter (101) comprises a load detector (209) detecting load variations for the power transfer signal and a preamble presence detector (213) correlates a second chip sequence with load variations and generates a preamble detection if the correlation exceeds a threshold. A load modulation receiver (207) determines load modulation data symbols based on a correlation of the first chip sequence and load variations of the power transfer signal. A synchronizer (215) synchronizes data symbol time intervals for the load modulation receiver (207) in response to a timing of the preamble detection, and the load modulation receiver (207) aligns the correlation of the first chip sequence and load variations to the data symbol time intervals. The power receiver (105) transmits the preamble and data symbols using the corresponding chip sequences.