Segmented Wireless Power Coil for Alignment Tolerance
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Solution Overview
Problem
Existing wireless power supply coils face challenges in aligning power-reception-side and power-transmission-side coils efficiently while minimizing weight increase, as larger magnetic bodies are required for increased tolerance, leading to increased weight and magnetic resistance.
Innovation Solution
The magnetic body is split along a coil-axis intersecting direction, with conductive wire wound around it, and a clearance is provided along the coil axis direction between split magnetic bodies, allowing for larger coil width and reduced weight while maintaining magnetic flux performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the width of the magnetic body is increased to increase tolerance for offset between coils, then alignment between power transmission and reception coils becomes easier, but the weight of the magnetic body increases
Solution Approach 1:
The magnetic body is divided into multiple segmented magnetic bodies arranged in parallel. Each segmented magnetic body has a smaller cross-sectional area than a single large magnetic body, reducing the amount of magnetic material required. The segments are spaced apart to form air gaps, which allows the overall structure to maintain a large effective width for alignment tolerance while using less material, thereby reducing weight.
2Ease of operation
If the width of the magnetic body is increased to increase tolerance for offset between coils, then alignment between power transmission and reception coils becomes easier, but the cost of the magnetic body increases
Solution Approach 1:
The magnetic body is divided into multiple segmented magnetic bodies arranged in parallel. Each segmented magnetic body has a smaller cross-sectional area than a single large magnetic body, reducing the amount of magnetic material required. The segments are spaced apart to form air gaps, which allows the overall structure to maintain a large effective width for alignment tolerance while using less material, thereby reducing cost.
3Weight of moving object
If a clearance is provided between split magnetic bodies, then the weight is reduced, but the magnetic resistance increases
Solution Approach 1:
The magnetic body is divided into multiple segmented magnetic bodies arranged in parallel. The segmentation reduces the total volume of magnetic material required, thereby reducing weight. The air gaps between segments do increase magnetic resistance locally, but the overall magnetic flux path is maintained through the parallel arrangement of segments, which compensates for the increased reluctance in the gaps.
Solution Approach 2:
Instead of increasing the width of a single solid magnetic body (one-dimensional approach), the invention uses multiple segmented bodies arranged in parallel with air gaps (multi-dimensional approach). This spatial reconfiguration allows the magnetic flux to distribute across multiple paths, maintaining effective magnetic coupling while reducing the total amount of magnetic material required, thereby reducing weight despite the presence of air gaps.
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 enables easier alignment between coils, reduces weight, and maintains self-inductance and coupling coefficient performance, despite the presence of clearances that act as magnetic resistance, thereby enhancing the efficiency of wireless power transfer.
Implementation Method 1
power is supplied from a power-transmission-side coil installed on the ground to a power-reception-side coil mounted on the lower surface of the vehicle body of an automobile by electromagnetic induction effect
Implementation Method 2
a magnetic flux that flows inside a magnetic body is directed in the coil axis direction
Data Source
AI summary
A magnetic core 47 to be housed in a coil bobbin 57 is split along a coil-axis intersecting direction Y into a plurality of split magnetic cores 47a, the coil-axis intersecting direction Y intersecting a coil axis direction X, and a clearance C extending along the coil axis direction X is provided between the plurality of split magnetic cores 47a. In each clearance C, a protrusion 51a protruding upward from a core base 51 is inserted and arranged to ensure sufficient rigidity. Providing the clearances C reduces the entire weight of the magnetic core 47 and also ensures a large coil width in the coil-axis intersecting direction Y. By ensuring a large coil width, alignment between a power-transmission-side coil 11 and a power-reception-side coil 13 becomes easier.