Expandable Magnetic Shield Cover for Wireless Power Transfer
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Solution Overview
Problem
Conventional wireless power supply systems fail to effectively shield leakage magnetic flux between the power-receiving and power-supplying coils, particularly when the power-receiving coil is positioned at the bottom of an electric vehicle and the power-supplying coil is buried in the ground, leading to environmental emission of magnetic flux.
Innovation Solution
An expandable and sealed cover with a gas supply and exhaust mechanism is used to inflate and deflate, covering the periphery of both coils and the space between them, incorporating materials with higher magnetic permeability for shielding, and utilizing magnetic flux transmitting and shielding portions to manage magnetic flux efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the cover is always inflated to cover the space between coils, then leakage magnetic flux is reduced, but the system complexity and cost increase
Solution Approach 1:
The expandable cover is inflated periodically only during wireless power transmission operations and deflated during normal vehicle operation. This periodic activation reduces the time the complex gas supply and exhaust mechanism is active, minimizing system complexity and operational costs while maintaining shielding effectiveness when needed.
Solution Approach 2:
The gas supply and exhaust mechanism is integrated with the wireless power transmission control system, automatically inflating the cover when power transmission is initiated and deflating it when transmission stops. This self-service approach eliminates the need for separate manual control systems, reducing overall system complexity.
2Object-affected harmful factors
If a rigid shield structure is used to cover the coil space, then leakage magnetic flux is blocked, but the positioning flexibility between coils is reduced
Solution Approach 1:
The expandable cover is constructed from flexible materials that can adapt to varying distances and relative positions between the power-receiving coil and power-supplying coil. This flexibility maintains effective shielding while accommodating positioning variations, unlike rigid structures that would require precise alignment and fixed geometries.
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 solution significantly reduces leakage magnetic flux emission to the environment, improves power transmission efficiency, and prevents foreign objects from entering the coil space, while allowing for precise positioning flexibility and cost-effective long-distance power transmission.
Implementation Method 1
a cover that is provided at least at one of the power-supplying device and the power-receiving device and that shields leakage magnetic flux by covering the periphery of the power-supplying coil and the power-receiving coil and a periphery of the space between the coils
Implementation Method 2
The gas supply and exhaust mechanism, when electric power is supplied, inflates the cover by supplying gas inside of the cover and establishes a shielding state from outside the cover where the inflated cover covers the periphery
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
A wireless power supply system (A) that wirelessly supplies electric power from a power-supplying coil (4) to a power-receiving coil (11) is provided with a ground power-supplying device (S) having a power-supplying coil (4), a vehicle (M) having a power-receiving coil (11), and a power-supplying and a power-receiving covers (5, 15) that shield leakage magnetic flux by covering the periphery of the power-supplying coil (4) and the power-receiving coil (11) and the periphery of space between the coils.