Interleaved Coil Segments for Wireless Power Transfer
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Solution Overview
Problem
Existing wireless power transfer technologies using single coils have limited transmitting area due to magnetic flux distribution, and multiple coil arrangements introduce unwanted electromagnetic interference (EMI) through parasitic inductance.
Innovation Solution
The implementation of a multiple interleaved coil structure, where each coil is formed from non-contiguous segments and interconnected in a way that the interconnects do not produce a magnetic field, allowing for a larger transmitting area without emitting EMI, using a configuration that can be applied in both transmitters and receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single coil is used for wireless power transfer, then the device structure is simple, but the transmitting area is limited due to magnetic flux distribution
Solution Approach 1:
The transmitter coil is divided into multiple interleaved coil segments (e.g., three segments labeled 322, 324, 326) that are spatially separated and interconnected. Each segment generates magnetic flux that contributes to the overall transmitting area, allowing the system to cover a larger area than a single coil of equivalent total length could achieve.
2Area of stationary object
If multiple coils are used to increase transmitting area, then the area coverage is improved, but unwanted electromagnetic interference is introduced through parasitic inductance
Solution Approach 1:
The harmful parasitic inductance loops are eliminated by removing the continuous conductive paths that would form such loops. The interconnect structure uses multiple separate conductors (e.g., four conductors labeled 336, 338, 340, 342) arranged to carry currents that cancel each other's magnetic field effects, thereby extracting the harmful EMI-generating aspect while retaining the useful area-expansion benefit.
Solution Approach 2:
The coil segments are arranged in an asymmetric interleaved pattern rather than a symmetric configuration. This asymmetric arrangement, combined with the specific interconnect topology, ensures that parasitic loops are broken and magnetic fields from adjacent segments cancel each other, reducing EMI while maintaining large transmitting area coverage.
3Area of stationary object
If the area of a single spiral coil is enlarged to increase transmitting area, then the coverage is improved, but the magnetic flux generated becomes weaker particularly in the middle of the coil
Solution Approach 1:
Instead of using one large coil, the system employs multiple smaller coil segments (322, 324, 326) distributed across the transmitting area. Each segment generates strong localized magnetic flux, and their combined effect provides both large area coverage and sufficient flux strength throughout the entire transmitting region, avoiding the flux weakness problem of large single coils.
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 enhances the area coverage for wireless power transfer while minimizing EMI, enabling more efficient power transmission without the drawbacks of parasitic inductance and interference.
Implementation Method 1
each of the plurality of incomplete coils configured such that an alternating current flowing in the incomplete coil produces a magnetic field
Implementation Method 2
the at least one interconnect including a plurality of conductors arranged in such a way that the alternating current flowing in the plurality of conductors does not produce a magnetic field
Data Source
AI summary
In one embodiment, a multiple interleaved coil structure for wireless power transfer includes a plurality of incomplete coils, each of the plurality of incomplete coils configured such that an alternating current flowing in the incomplete coil produces a magnetic field, and at least one interconnect between the plurality of incomplete coils, the at least one interconnect including a plurality of conductors arranged in such a way that the alternating current flowing in the plurality of conductors does not produce a magnetic field. Each of the plurality of incomplete coils includes a plurality of non-contiguous segments arranged in such a way that the incomplete coil will emit magnetic flux in response to an applied alternating current. The multiple interleaved coil structure can be implemented in a wireless power transmitter or a wireless power receiver.