Contactless Power Supply Coil Winding and Resonance Configuration
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Solution Overview
Problem
Existing contactless power supply systems face inefficiencies in electric power transmission due to heat generation and loss in primary, secondary, and resonance coils, particularly when supplying large amounts of power, leading to increased resistance and eddy-current losses.
Innovation Solution
A contactless power supply system utilizing a primary coil connected to a high-frequency power source, a secondary coil, and a resonance coil with specific winding configurations and geometries, including planar and spirally wound litz wires, tandem double-layer winding for the resonance coil, and strategically placed rod-like ferrite cores and aluminum plates to minimize leakage magnetic flux and enhance cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a resonance coil is added to improve power transmission efficiency, then power supply efficiency is improved, but heat generation and loss in the resonance coil increases
Solution Approach 1:
The patent optimizes the resonance frequency of the resonance coil to match the operating frequency of the primary coil, maximizing power transfer efficiency while minimizing energy loss. By carefully selecting the capacitance value and coil parameters, the system achieves resonant coupling that reduces the current required in the resonance coil for a given power transfer level.
Solution Approach 2:
The resonance coil acts as an intermediary element that facilitates power transfer from the primary coil to the secondary coil. By introducing this intermediate resonant circuit, the system achieves better coupling and efficiency compared to direct inductive coupling, while the resonant conditions minimize the energy dissipation in the intermediary itself.
2Productivity
If the area of secondary coil and resonance coil is increased to improve power transfer, then power supply efficiency is improved, but the system becomes less compact and more complex
Solution Approach 1:
The patent places the resonance coil inside or adjacent to the secondary coil, creating a nested configuration. This allows both coils to occupy the same or overlapping spatial footprint, achieving effective power transfer with larger equivalent areas without proportionally increasing the physical envelope of the device.
Solution Approach 2:
The patent utilizes three-dimensional spatial arrangement by stacking coils in different layers or positions. The resonance coil and secondary coil are arranged in a configuration that exploits the third dimension (depth/height) rather than simply expanding in the planar area, maintaining compactness while achieving the necessary effective areas for efficient power 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 system achieves efficient power transmission by reducing power loss and heat generation, improving efficiency through the use of litz wires and optimized coil geometries, while maintaining a compact design suitable for service vehicles and cars.
Implementation Method 1
a primary coil to be connected to a high-frequency power source, a secondary coil to receive electric power generated from the primary coil
Implementation Method 2
a resonance coil arranged in direct contact with the secondary coil in between the primary coil and the secondary coil
Data Source
AI summary
In a contactless power supply system 10 having a secondary coil 13 receiving electric power generated from a primary coil 12 to be connected to a high-frequency power source 11, and a resonance coil 14 arranged in direct contact with the secondary coil 13 in between the primary coil 12 and the secondary coil 13, respective planarly-viewed areas of the secondary and the resonance coils 13, 14 are equal to or smaller than a planarly-viewed area of the primary coil 12, the primary coil 12 is formed by planarly and spirally winding a first litz wire 25, the resonance coil 14 is formed by tandemly winding coils 27, 28 in a double layer, the coils 27, 28 being formed by planarly and spirally winding a second litz wire 26, and the secondary coil 13 is formed by parallelly arranging and planarly and spirally winding third litz wires 29, 29a.