Crossover Coil Winding Layout for Lower Wireless Charging Loss
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Solution Overview
Problem
Wireless charging efficiency is compromised due to significant eddy current and circulating current losses in coil windings caused by strong magnetic fields and cutting openings, which split the coil into smaller windings, leading to induced currents with different directions.
Innovation Solution
A coil winding design featuring an insulation layer with two segments of conducting wire, each divided into multiple sub-wires by cutting openings, where these sub-wires are electrically connected in pairs to form crossover structures, allowing induced currents to cancel each other out and reduce circulating current losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the coil winding is made wider to improve charging performance, then wireless charging efficiency improves, but eddy current loss increases
Solution Approach 1:
The wider coil winding is segmented into multiple narrower sub-windings through cutting openings. This maintains the overall larger area for better magnetic coupling and charging performance while each individual sub-winding remains narrow enough to minimize eddy current loss.
Solution Approach 2:
Multiple segmented sub-windings are electrically connected in series or parallel to form a combined coil structure that achieves the desired equivalent width for effective wireless charging while maintaining low eddy current losses through the segmented architecture.
2Loss of energy
If cutting openings are added to reduce eddy current loss, then the coil structure becomes more complex
Solution Approach 1:
The coil is segmented using cutting openings that can be implemented through standard PCB fabrication techniques or laser cutting, adding minimal structural complexity while achieving significant eddy current loss reduction.
Solution Approach 2:
The cutting opening pattern is replicated across the coil winding at regular intervals, creating a standardized modular structure that simplifies manufacturing and reduces design complexity through repetition rather than custom features.
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 effectively minimizes circulating current losses and enhances wireless charging efficiency by ensuring that induced currents generated by magnetic fields in the coil winding are opposite in direction and equal in size, thereby improving overall charging performance.
Implementation Method 1
an alternating current carried by the transmitting coil in the wireless charger generates a magnetic field, and the receiving coil in the electronic device generates a voltage through magnetic coupling
Implementation Method 2
a relatively large eddy current loss is generated in the coil winding when the magnetic field passes through the coil winding
Implementation Method 3
induced currents IE that are in different directions are generated in the two small windings on two sides of the cutting opening due to electromagnetic induction
Data Source
AI summary
A coil winding includes a first part of coils and a second part of coils located on opposite sides of an insulation layer, where the first part of coils comprises a first segment of conducting wire, and the second part of coils comprises a second segment of conducting wire. The first segment of conducting wire and the second segment of conducting wire each includes N cutting openings. Both the first segment of conducting wire and the second segment of conducting wire are divided into N+1 sub conducting wires by the N cutting openings. The N+1 sub conducting wires in the first segment of conducting wire and the N+1 sub conducting wires in the second segment of conducting wire are electrically coupled in a one-to-one manner to form N+1 pairs of sub conducting wires including a crossover structure.