Segmented Power Transfer Coils for Positional Displacement Tolerance
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Solution Overview
Problem
Existing power transfer systems experience a significant decrease in coupling coefficient and transmission efficiency when the power transmission coil and power receiving coil become positionally displaced, leading to variations in coupling efficiency between correctly positioned and displaced states.
Innovation Solution
The power transmission and receiving coils are wound such that the first power transmission winding portion and the first power receiving winding portion overlap when positionally displaced, while the second power transmission and receiving winding portions do not overlap, maintaining a high coupling coefficient by forming a magnetic circuit only between the first power transmission and receiving winding portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power transmission coil and power receiving coil are positioned to overlap completely, then the coupling coefficient is maximized in the correctly positioned state, but the coupling coefficient decreases significantly when positional displacement occurs
Solution Approach 1:
The power transmission coil is divided into a first power transmission winding portion and a second power transmission winding portion, and the power receiving coil is divided into a first power receiving winding portion and a second power receiving winding portion. This segmentation allows selective magnetic circuit formation between specific portions, improving positional displacement tolerance while maintaining coupling coefficient.
Solution Approach 2:
The patent applies different spatial arrangements to different portions of the coils. The first power transmission winding portion and first power receiving winding portion are arranged to form a magnetic circuit when displaced, while the second portions are arranged to avoid forming a magnetic circuit when displaced. This local differentiation resolves the contradiction between maximizing coupling and tolerating displacement.
2Reliability
If the coil sizes are increased to improve positional displacement performance, then the coupling coefficient is maintained better under displacement, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of increasing overall coil size, the patent segments the coils into portions with specific spatial arrangements. This achieves positional displacement performance improvement without proportionally increasing device complexity, as the segmentation uses existing coil structures in different configurations.
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 reduces variations in the coupling coefficient and maintains high transmission efficiency in both correctly positioned and displaced states, minimizing the impact of positional displacement on power transfer.
Implementation Method 1
a power transfer system including a power receiving device which contactlessly receives electric power from a power transmission device
Data Source
Figure 1
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AI summary
In this power transfer system, a power receiving coil (250) and a power transmission coil (450) are wound such that a first power transmission winding portion (450a) and a second power receiving winding portion (250b) do not overlap with each other when the first power transmission winding portion (450a) and the first power receiving winding portion (250a) overlap with each other at a position where a power transmission winding axis (CL1) and a power receiving winding axis (CL2) are positionally displaced when viewed in a plan view.