Wireless Power Transfer Load Modulation With Chip Sequence Decoding
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Solution Overview
Problem
Existing wireless power transfer systems face challenges such as electromagnetic interference, acoustic noise, and communication errors due to load modulation, particularly in high power applications, which affect compatibility and reliability.
Innovation Solution
Implementing a communication method that uses chip sequences with varying load modulation patterns for each data symbol, allowing the power transmitter to detect data by correlating measured load values with stored sequences, reducing modulation depth and noise.
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 patent segments each data symbol into multiple chips (e.g., 3-15 chips per symbol), where each chip is transmitted with a specific load modulation pattern. This segmentation allows the communication signal to be distributed across multiple time intervals, reducing the peak modulation depth required for each individual chip and thereby reducing electromagnetic interference and acoustic noise while maintaining communication reliability through correlation decoding.
2Reliability
If load modulation depth is increased to improve signal detection, then communication reliability improves, but acoustic noise and electromagnetic interference worsen
Solution Approach 1:
The patent applies preliminary encoding of data symbols into chip sequences before transmission. Each data symbol is pre-encoded into a sequence of chips with specific load modulation patterns. This preliminary action allows the receiver to use correlation decoding to detect the transmitted symbol by matching the received chip sequence against a codebook of possible sequences, enabling reliable communication at lower modulation depths and reducing acoustic noise and electromagnetic interference.
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, improves compatibility, and maintains backwards compatibility with existing systems, while allowing efficient power transfer.
Implementation Method 1
power is inductively transferred from a transmitter coil in a power transmitter device to a receiver coil in the individual devices
Implementation Method 2
power is inductively transferred from a transmitter coil in a power transmitter device to a receiver coil in the individual devices
Data Source
AI summary
A power receiver (105) communicates to a power transmitter (101) using load modulation data symbols modulated by a chip sequence with a chip sequence being divided into load time intervals with different modulation loads. The power transmitter (101) comprises a receiver (207) which includes a load measurer (209) determining measured load values of the power transfer signal for load time intervals. A chip determiner circuit (211) determines a received chip sequence from the measured load values where the received chip sequence comprises a sequence of chip values. Each chip value is determined in response to a difference between measured load values for at least two modulation load time intervals of the chip. A store (215) stores a set of chip sequences with each chip sequence linked to a data symbol. A detector (213) detects a received data symbol value in response to a correlation between the received chip sequence and chip sequences of the set of chip sequences.