Ferrite Wing Secondary Coil for Misalignment-Tolerant Wireless Charging
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Solution Overview
Problem
Dynamic wireless power transfer systems face challenges with very low or no coupling when the secondary coil is misaligned from the primary coil, particularly during motion, leading to discontinuous power transfer.
Innovation Solution
The addition of ferrite wings to the secondary coil enhances the coil geometry, increasing the surface area and improving alignment with the primary coil, thereby enhancing mutual inductance and ensuring continuous power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the secondary coil is misaligned from the primary coil during motion, then the coupling coefficient decreases to very low or zero, but adding ferrite wings increases device complexity and material usage
Solution Approach 1:
The patent extends the secondary coil structure from a planar geometry to a three-dimensional configuration by adding ferrite wings that protrude laterally. This dimensional extension increases the effective coupling area and allows the secondary coil to maintain magnetic flux linkage with the primary coil even when misaligned during motion, thereby ensuring continuous power transfer despite position variations.
Solution Approach 2:
The patent combines traditional coil windings with ferrite magnetic material to create a composite structure. The ferrite wings serve as magnetic flux conduits that guide and concentrate magnetic fields, enhancing the coupling between primary and secondary coils. This composite approach improves power transfer reliability while managing the added complexity through efficient material utilization.
2Power
If ferrite wings are added to increase coupling, then mutual inductance improves, but the amount of ferrite material required increases
Solution Approach 1:
Instead of uniformly increasing ferrite material throughout the entire coil structure, the patent applies ferrite wings only at specific strategic locations where magnetic flux concentration provides maximum benefit. The wings are positioned to extend laterally from the secondary coil in regions where they most effectively intercept and guide magnetic flux from the primary coil, optimizing power transfer efficiency while minimizing material consumption.
Solution Approach 2:
The patent implements ferrite wings with dimensions that are sufficient to achieve the required coupling improvement but not excessively large. The wing size and extension are optimized to provide just enough additional magnetic flux pathway to maintain continuous power transfer during motion, avoiding unnecessary material usage while ensuring adequate coupling enhancement.
3Ease of manufacture
If the transmitter coil size is standardized for industrialization, then manufacturing ease improves, but coupling efficiency decreases with varying ground clearances
Solution Approach 1:
The patent creates a dynamic compensation mechanism where the ferrite wings on the secondary coil adapt to varying ground clearances. As the distance between primary and secondary coils changes, the ferrite wings extend laterally to increase the effective coupling area, dynamically maintaining optimal magnetic flux linkage. This dynamic geometry allows standardized transmitter coils to maintain efficient coupling across different vehicle types and ground clearance variations.
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 ferrite wings improve coupling efficiency, allowing for continuous power transfer across varying alignments and distances, maintaining efficient energy transfer even when the secondary coil moves relative to the primary coil.
Implementation Method 1
Inductive wireless power transfer happens when a primary coil (transmitter) is excited with an alternating electric current at a given frequency. This generates a magnetic flux in the primary coil. A secondary coil (receiver) in close proximity to the primary coil is influenced by this magnetic flux and a current can be induced in the secondary coil due to the presence of the magnetic flux emanating from the primary coil.
Implementation Method 2
The invention includes ferrite wings that provide an additional coil geometry to improve coupling between a primary coil and a secondary coil. The invention adds additional pieces of ferrite on top of the secondary coil to improve inductive wireless power transfer
Data Source
AI summary
Systems and devices for wireless power transmission is provided. A system includes a ground assembly and a vehicle assembly. The ground assembly includes a primary coil and a magnetic permeable core. The vehicle assembly includes a secondary coil capable of being inductively coupled to the primary coil and one or more magnetic permeable wings disposed on top of the secondary coil. Each of the one or more magnetic permeable wings overlap the secondary coil such that each of the one or more magnetic permeable wings extend within and beyond a periphery of the secondary coil for generating additional coupling between the primary coil and the secondary coil.