Dual-Coil Demodulation for Uniform Wireless Power Transfer
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Solution Overview
Problem
Existing wireless power transmission systems face challenges in achieving uniform power transmission over large areas, particularly when the receiver is in motion, due to variations in the strength of the emitted field, and often require more conductive materials that increase costs and environmental concerns.
Innovation Solution
The design incorporates a transmitter antenna with a source coil and an internal repeater coil, featuring alternating current directions and inter-turn capacitors, which enhances uniformity and metal resilience while minimizing the use of conductive materials and reducing electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If more conductive materials (coils, turns, resonant bodies) are used to maximize uniformity ratio, then uniformity of power transmission is improved, but cost and environmental impact increase
Solution Approach 1:
The transmitter antenna is divided into a source coil and an internal repeater coil, where the repeater coil is positioned within the source coil. This segmentation allows the system to achieve enhanced uniformity without proportionally increasing total conductive material, as the repeater coil reinforces the magnetic field in specific regions rather than requiring uniform distribution of additional materials throughout the entire antenna structure.
Solution Approach 2:
The internal repeater coil acts as an intermediary element that modifies the magnetic field distribution within the charge area. By positioning the repeater coil inside the source coil and configuring it with alternating current directions, the system achieves field uniformity enhancement without directly adding equivalent amounts of conductive material across the entire antenna, thus resolving the contradiction between uniformity and material quantity.
2Reliability
If internal repeater coil is added to enhance uniformity, then power transmission uniformity is improved, but device complexity increases
Solution Approach 1:
The internal repeater coil is nested within the source coil structure, with the repeater coil positioned inside the larger source coil. This nesting approach allows the system to achieve enhanced uniformity while minimizing structural complexity, as the repeater coil utilizes the existing spatial framework of the source coil rather than requiring separate, additional structural support systems.
Solution Approach 2:
The internal repeater coil serves multiple functions: it enhances magnetic field uniformity, contributes to metal resiliency, and participates in both power transmission and communications demodulation. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in overall device complexity despite the addition of the repeater coil.
3Productivity
If source coil and repeater coil are tightly coupled, then power transmission efficiency is improved, but electromagnetic interference increases
Solution Approach 1:
The source coil and repeater coil are configured with alternating current directions, creating localized magnetic field patterns that reinforce each other in the charge area while canceling interference in other regions. This local quality differentiation allows tight coupling for efficiency while mitigating electromagnetic interference through directional field cancellation.
Solution Approach 2:
The potential electromagnetic interference generated by the interaction between source coil and repeater coil is converted into a beneficial effect through the alternating current configuration. The interference patterns that would normally be harmful are redirected to create constructive interference in the charge area, enhancing field uniformity while maintaining efficiency.
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 configuration ensures consistent and efficient wireless power transmission over a large area with improved uniformity and reduced environmental impact, allowing for effective operation in diverse orientations and coupling conditions.
Implementation Method 1
inductive and/or resonant inductive wireless power transfer, which occurs when magnetic fields created by a transmitting element induce an electric field and, hence, an electric current, in a receiving element
Implementation Method 2
The source coil and the internal repeater coil may be configured with alternating current directions, which may improve uniformity and metal resiliency
Implementation Method 3
resonant inductive wireless power transfer... self-resonant frequency restraints... repeater tuning system may be disposed within or in close proximity to the internal repeater coil
Data Source
AI summary
A wireless power transmission system includes a transmission antenna that has a source antenna coil and an internal repeater coil. The system further includes two demodulation circuits, for demodulating incoming communications from a power receiver. One demodulation circuit receives sensed signals at the source coil and the other receives sensed signals at the internal repeater coil. The pair of sensed signals are then summed at a summing amplifier to generate a communications signal for input to a controller of the wireless power transmission system.