Magnetic Coupling Structure for Inductive Power Transfer Misalignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inductive power transfer (IPT) systems for electric vehicles face challenges in achieving efficient and cost-effective power transfer over a wide range of air gaps and misalignment tolerances, particularly with circular pad designs that suffer from reduced power transfer and increased stress on the power supply due to varying self and mutual inductance with distance.
Innovation Solution
The use of a magnetic coupling structure with a circular transmitter coil and a receiver core featuring an E-shaped or lattice structure with multiple coils, allowing for orthogonal and quadrature flux components to be extracted, providing greater coupling tolerance and power transfer over a wider range of movements and misalignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circular pad design is used for inductive power transfer, then the system is simple and easy to manufacture, but power transfer efficiency decreases and stress on power supply increases when air gap or misalignment varies
Solution Approach 1:
The receiver pad is segmented into multiple independent coils (typically three coils arranged at 120 degrees) instead of a single circular coil. Each coil is independently connected to the power supply, allowing the system to maintain efficient power transfer across a wider range of misalignments and air gaps by having multiple active coupling paths
Solution Approach 2:
Multiple coils are merged into a single receiver pad structure with a common magnetic core and shared control circuitry. The coils work together to provide redundant and complementary magnetic coupling paths, combining their individual contributions to achieve improved overall power transfer efficiency and reduced stress on the power supply
2Ease of operation
If the air gap between couplers is increased to allow greater tolerance, then ease of operation improves, but coupling coefficient decreases significantly
Solution Approach 1:
The system dynamically adapts to varying air gaps through independent control of multiple coils. The power supply can adjust the excitation current distribution among the three coils based on the actual coupling conditions, maintaining optimal power transfer efficiency across a range of air gap distances rather than being fixed for a single gap value
3Device complexity
If a single coil receiver is used, then device complexity is low, but coupling tolerance to misalignment is poor
Solution Approach 1:
The receiver is segmented into three spatially distributed coils arranged at 120 degrees around the magnetic core. This segmentation provides multiple independent magnetic coupling paths to the transmitter, significantly improving tolerance to lateral misalignment while keeping each individual coil simple in structure
Solution Approach 2:
The multi-coil receiver structure serves multiple functions: it provides redundant coupling paths for misalignment tolerance, enables dynamic power distribution among coils based on coupling conditions, and maintains compatibility with standard circular transmitter pads. The same structure can operate effectively across various air gaps and alignment conditions
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 enhances the IPT system's ability to maintain efficient power transfer and stability across a broader range of air gaps and misalignments, improving the reliability and cost-effectiveness of electric vehicle charging systems.
Implementation Method 1
the structures being adapted to generate and/or receive magnetic flux to thereby transfer power inductively
Implementation Method 2
an arrangement of at least two coils associated with a magnetically permeable core
Data Source
AI summary
Inductive power transfer apparatus has a first magnetic coupling structure and a second magnetic coupling structure, the structures being adapted to generate and/or receive magnetic flux to thereby transfer power inductively, the first structure comprising a substantially circular coil, and the second magnetic structure comprising an arrangement of at least two coils associated with a magnetically permeable core.