Integrated Tuning Capacitors in Wireless Charging Coils
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Solution Overview
Problem
Existing wireless electric vehicle charging systems require alignment of transmit and receive couplers, which can be cumbersome and increase the size of the transmit coupler structure due to integrated tuning capacitors for impedance matching.
Innovation Solution
The integration of tuning capacitance directly over a ferrite element in a low flux region of the charging coil structure, minimizing the overall size and thickness while maintaining efficient impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tuning capacitors are integrated into the charging coil structure, then impedance matching efficiency is improved, but the thickness and overall size of the transmit coupler structure increases
Solution Approach 1:
The patent positions tuning capacitors in the horizontal plane rather than stacking them vertically, utilizing the low flux region laterally adjacent to the coil structure. This dimensional repositioning maintains impedance matching functionality while avoiding vertical space consumption, thus resolving the contradiction between matching efficiency and structural thickness.
Solution Approach 2:
The patent places tuning capacitors specifically in the low flux region next to the coil structure, where magnetic flux density is minimal. This localized positioning allows capacitors to perform impedance matching without being exposed to high flux conditions, enabling thin-profile design while maintaining electrical performance.
2Reliability
If tuning capacitors are integrated into the charging coil structure, then impedance matching is improved, but the overall size of the transmit coupler structure increases
Solution Approach 1:
The patent utilizes the horizontal space adjacent to the coil structure rather than expanding the vertical profile. By positioning capacitors in the low flux region laterally, the design achieves impedance matching without increasing the overall footprint or thickness of the transmit coupler assembly.
Solution Approach 2:
The patent employs planar capacitor structures that can be fabricated using standard PCB or ceramic capacitor technologies, allowing compact integration alongside the coil structure. This approach enables impedance matching functionality with minimal space occupation in the horizontal plane.
3Reliability
If tuning capacitors are placed in high flux regions, then impedance matching is achieved, but eddy current effects and heating increase
Solution Approach 1:
The patent specifically positions tuning capacitors in the low flux region adjacent to the coil structure, where magnetic flux density is minimal. This localized placement allows capacitors to provide impedance matching while avoiding exposure to high magnetic flux that would induce eddy currents and generate heat, thus eliminating the harmful effects.
Solution Approach 2:
The patent introduces a non-magnetic spacer or support structure as an intermediary between the coil structure and the tuning capacitors. This intermediary positions the capacitors in the low flux region while maintaining electrical connectivity, acting as a mediator that separates the capacitor from the high flux environment to prevent eddy current heating.
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 allows for efficient wireless power transfer with reduced size and thickness of the transmit coupler, minimizing eddy current effects and heating, while maintaining effective impedance matching and power transfer efficiency.
Implementation Method 1
a plurality of coil structures located over a ferrite element, the plurality of coil structures configured to generate a high flux region and a low flux region
Implementation Method 2
a plurality of coil structures located over a ferrite element
Implementation Method 3
a tuning capacitance located directly over the ferrite element in the low flux region
Data Source
AI summary
Systems, methods, and apparatus are disclosed for power transfer including a plurality of coil structures located over a ferrite element, the plurality of coil structures configured to generate a high flux region and a low flux region, the low flux region being located between the plurality of coil structures, and a tuning capacitance located directly over the ferrite element in the low flux region.