Universal Demodulation Circuit for Wireless Power Transfer
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Solution Overview
Problem
Existing wireless power transfer technologies face challenges in implementing a universal demodulation method that can effectively handle various load modulation methods and changing loading conditions, particularly due to the complexity introduced by different power requirements and relative positions of transmitter and receiver coils.
Innovation Solution
A demodulation circuit that utilizes a vector sum of electrical parameters to detect impedance modulation, allowing for the determination of both amplitude and phase changes, enabling universal demodulation without the need for complex additional components, and a modulation circuit that modulates impedance to ensure data communication across different loading conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If amplitude demodulation is used in RFID systems, then data transfer is achieved with simple circuits, but the method is not valid for wireless power transfer with wide range of loads
Solution Approach 1:
The patent implements a universal demodulation circuit that can handle multiple modulation types (AM, PM, and their combinations) through a single unified architecture. The circuit uses vector sum decomposition of electrical parameters to universally demodulate any impedance modulation regardless of whether it manifests as amplitude changes, phase changes, or both, thereby achieving multi-functionality without requiring separate circuits for different modulation schemes.
Solution Approach 2:
The patent changes the demodulation approach from simple amplitude detection to vector-based parameter analysis. By representing electrical parameters as vectors and computing their vector sums, the system can extract both amplitude and phase information from impedance modulations, adapting to different loading conditions through parameter transformation rather than circuit reconfiguration.
2Loss of information
If load modulation is used for data transfer from receiver to transmitter, then data communication is achieved, but the method becomes complex under different power requirements and relative positions
Solution Approach 1:
The patent introduces an intermediary mathematical framework (vector sum decomposition) between the load modulation signal and the demodulation process. Instead of directly detecting amplitude or phase changes which become ambiguous under varying coupling conditions, the system uses vector representation as an intermediary to unambiguously extract data from impedance modulations regardless of their specific manifestation form.
Solution Approach 2:
The patent segments the impedance modulation detection into two independent components: amplitude component and phase component. By treating these as separate vector elements that can be independently analyzed and then recombined, the system simplifies the demodulation process while maintaining the ability to handle complex loading conditions that would otherwise require a monolithic complex detection scheme.
3Loss of information
If extra coils are added for data transfer, then bidirectional communication is achieved, but component count and cost increase
Solution Approach 1:
The patent makes the existing power transfer coil serve dual functions: both power transfer and data communication. By demonstrating that impedance modulations on the same coil can be universally demodulated using the vector-based method, the invention eliminates the need for separate dedicated communication coils, achieving multi-functionality without requiring additional physical components for data transfer.
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 solution enables efficient and universal data communication in wireless power transfer systems, ensuring compatibility with diverse receivers and loading conditions, reducing component complexity and cost, while maintaining effective power transfer.
Implementation Method 1
a first power transfer coil (5) for inductive coupling with a second power transfer coil (6)
Implementation Method 2
modulation of the impedance of the demodulation circuit results in corresponding modulation of one or both of the amplitude and phase of the first electrical parameter, the corresponding modulation being determinable by detecting the amplitude of the first electrical parameter and the amplitude of the second electrical parameter
Data Source
AI summary
The present invention provides a universal demodulation circuit, a load modulation circuit and associated method, and an associated power transfer system, all suitable for use in wireless power transfer. A power receiver with signal strength detection is also provided. Modulation of the impedance of the demodulation circuit is determinable by detecting the amplitudes of a first and a second electrical parameter, thereby demodulating data communicated by modulation of the impedance of the demodulation circuit. The modulation circuit has a communication modulator to modulate the impedance of the modulation circuit, to a predetermined minimum modulation depth, thereby to communicate data.