Coil Unit Magnetic Body Design for Wireless Power Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless power transmission efficiency is reduced due to positional shifts between transmission and power receiving coils, leading to increased leakage magnetic fields that can interfere with peripheral electronic devices.
Innovation Solution
A coil unit design with a magnetic body having distinct portions positioned outside the conductive plate, forming a magnetic path with low magnetoresistance, and a non-magnetic conductive plate to prevent excessive magnetic coupling and leakage fields, ensuring efficient power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a coil with helical winding is used to increase power transmission efficiency, then power transmission efficiency is improved, but leakage magnetic field strength increases causing electromagnetic interference
Solution Approach 1:
A magnetic body is introduced as an intermediary component between the coil and the surrounding environment. This magnetic body provides a dedicated magnetic flux path that confines the magnetic field within a controlled region, preventing excessive leakage into the surrounding space while maintaining efficient power transmission through the coil.
Solution Approach 2:
The invention changes the magnetic properties of the surrounding environment by introducing a magnetic body with specific permeability characteristics. This alters the magnetic flux distribution, directing it through the magnetic body rather than allowing it to disperse freely, thereby reducing leakage magnetic field strength while preserving power transmission efficiency.
2Adaptability or versatility
If multiple cores are disposed at predetermined intervals to resist positional shifts, then adaptability to positional shifts is improved, but device complexity increases
Solution Approach 1:
The magnetic body serves multiple functions simultaneously: it provides a magnetic flux path for efficient power transmission, acts as a positional reference structure, and reduces leakage magnetic field. This multi-functionality achieves adaptability to positional shifts without proportionally increasing device complexity.
3Object-generated harmful factors
If magnetic body extends beyond conductive plate to reduce leakage field, then leakage magnetic field is reduced, but magnetic coupling may excessively increase
Solution Approach 1:
The magnetic body is strategically positioned to extend beyond the conductive plate only in regions where leakage field reduction is needed, while maintaining appropriate coupling in the central region. This localized extension achieves leakage field reduction without causing excessive magnetic coupling that would destabilize power transmission.
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 solution effectively suppresses power transmission efficiency decreases and reduces unnecessary leakage magnetic fields, maintaining efficient power transfer even with coil position shifts.
Implementation Method 1
a magnetic path with a low magnetoresistance is formed. That is, a magnetoresistance of a magnetic path which passes through the magnetic body is smaller than a magnetoresistance of a magnetic path which is widely circulated up to a place separated from the coil unit. Thus, the magnetic flux easily forms the magnetic path which passes through the magnetic body
Implementation Method 2
a magnetoresistance of a magnetic path which passes through the magnetic body is smaller than a magnetoresistance of a magnetic path which is widely circulated up to a place separated from the coil unit
Implementation Method 3
since magnetic coupling of the coil and the magnetic body is prevented from excessively increasing by the non-magnetic conductive plate which is disposed in the axis direction of the coil, magnetic coupling of a transmission side and a power receiving side in the wireless power transmission can be prevented from significantly decreasing
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A coil unit includes a non-magnetic conductive plate which is disposed along an axis of a coil, and a magnetic body. The magnetic body includes a first portion which is positioned in an outer side than an outline of one side of the conductive plate in the axis direction of the coil, and a second portion which is positioned in an outer side than an outline of the other side of the conductive plate in the axis direction of the coil. When viewing from the axis direction of the coil, the first and second portions are positioned on a side of the conductive plate where is opposite to a side which faces the coil.