Segmented Coil Asymmetry Reduces Leakage Magnetic Field
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-contact power transmission systems for electric vehicles face inefficiencies due to significant leakage magnetic fields, which cause radiation noise and induction heating in surrounding metal components, leading to reduced power transmission efficiency and component degradation.
Innovation Solution
A coil design with a core formed by ferrite elements and an insulating resin bobbin, featuring a single wire wound around the center and ends of the core in a swirl pattern, with different winding axes for the first and second coils, effectively orienting the magnetic field towards the receiving coil and reducing leakage magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional double-side winding coil is used, then the system is tolerant of horizontal misalignment and vertical gap variation, but significant leakage magnetic field is generated causing radiation noise and induction heating
Solution Approach 1:
The coil structure is segmented into a center coil and two end coils, each serving distinct functions. The center coil provides primary power transmission, while the end coils specifically target leakage magnetic field reduction. This segmentation allows independent optimization of each coil's characteristics to achieve both alignment tolerance and reduced leakage.
Solution Approach 2:
Different regions of the coil structure are assigned different winding densities and configurations. The center portion has a specific winding density for optimal power transfer, while the end portions have modified winding patterns specifically designed to contain magnetic flux. This local differentiation optimizes each region's contribution to overall system performance.
2Object-generated harmful factors
If a metal shield is provided to reduce leakage magnetic field, then radiation noise is reduced, but induction heating of the metal shield occurs causing power transmission efficiency deterioration and component degradation
Solution Approach 1:
Ferrite elements are introduced as an intermediary material between the coil and the external environment. These ferrite elements guide and contain the magnetic flux within the non-contact power transmission system, preventing leakage without requiring metal shields that would cause induction heating. The ferrite acts as a magnetic flux mediator that directs field lines appropriately.
3Power
If the magnetic field is radiated mostly from the core, then power transmission is achieved, but significant leakage magnetic field increases magnetic flux density around the system exposing human body and generating radiation noise
Solution Approach 1:
The coil structure employs asymmetric winding patterns where the end coils have different characteristics from the center coil. The end coils are specifically configured with winding directions and densities that create opposing magnetic fields to cancel leakage, while the center coil maintains optimal power transmission characteristics. This asymmetric design allows differential optimization of power transfer versus leakage reduction.
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 design minimizes radiation noise and induction heating, enhancing power transmission efficiency by focusing the magnetic field towards the intended coil and reducing heat generation in metal components, thus improving the overall performance and reliability of the non-contact power transmission system.
Implementation Method 1
an RF current is supplied to a wire to transmit electric power, and the magnetic field is radiated mostly from a core
Implementation Method 2
the leakage magnetic field inductively heats the metal shield itself and makes the metal shield generates some heat
Data Source
Figure 1A~2
Figure 3A~4C
Figure 5A~6C
AI summary
A coil for a non-contact power transmission system according to the present invention is used in a non-contact power transmission system to transmit electric power via a non-contact method. The coil includes a first coil 4 in which a wire 3 is wound around at a center of a core 1; and a second coil 5 placed at an end of the core 1, and wound with the wire 3. Winding axes of the first and second coils 4 and 5 are oriented in different directions.