Segmented Magnetic Shielding for Wireless Charging Heat Reduction
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Solution Overview
Problem
Low-frequency wireless charging technologies face challenges in increasing coupling voltage while maintaining efficient energy transfer, as higher coupling inductance limits transmission distance and results in increased magnetic field intensity, leading to heat generation in metal foreign matter and charging devices.
Innovation Solution
An electromagnetic shielding device using a magnetic sheet with a hollow portion, positioned between the power transmitting and receiving coils, reduces the magnetic field on metal materials and increases the coupling coefficient without altering the required voltage, thereby minimizing heat and loss during wireless charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the current in the power transmitting coil is increased to increase the intensity of the magnetic field, then the induced voltage in the power receiving coil is improved, but the magnetic field intensity increases causing metal materials to generate heat and increase power consumption
Solution Approach 1:
The magnetic sheet is divided into multiple segments with different magnetic permeability values. The first magnetic sheet has a first magnetic permeability value, while the second magnetic sheet has a second magnetic permeability value different from the first. This segmentation allows different regions to provide different levels of magnetic field shielding, reducing heat generation in metal materials while maintaining sufficient induced voltage for wireless charging.
Solution Approach 2:
Different regions of the magnetic shielding structure are assigned different magnetic permeability properties. The first magnetic sheet covers a first area with a specific magnetic permeability, while the second magnetic sheet covers a second area with a different magnetic permeability. This local quality differentiation enables optimized magnetic field distribution, reducing harmful heating effects in specific metal regions while preserving charging functionality.
2Power
If the coupling inductance is increased to increase the induced voltage, then the wireless charging efficiency is improved, but the transmission distance is limited
Solution Approach 1:
The patent utilizes changes in magnetic permeability parameters of the magnetic sheets to optimize the magnetic coupling between transmitting and receiving coils. By selecting magnetic sheets with appropriate permeability values, the system achieves enhanced coupling inductance without requiring excessive current, thereby improving induced voltage while maintaining feasible transmission distances.
3Power
If the magnetic field intensity is increased to satisfy the requirement of sufficient coupling voltage, then the wireless charging performance is improved, but the power consumption increases due to heat generation
Solution Approach 1:
The magnetic shielding structure is segmented into multiple zones with different magnetic permeability characteristics. This segmentation enables precise control over magnetic field distribution, allowing the system to achieve sufficient coupling voltage at the receiving coil while minimizing excessive magnetic field intensity in regions where it would cause harmful heating and energy loss.
Solution Approach 2:
The patent converts the potentially harmful effect of strong magnetic fields (which cause heating in metal materials) into a beneficial shielding effect. By strategically placing magnetic sheets with appropriate permeability values, the system directs and contains the magnetic field where it is needed for charging while shielding areas where it would cause harmful heating, thus reducing overall energy loss.
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 solution effectively reduces the magnetic field intensity on metal materials and enhances coupling efficiency, improving the overall performance and efficiency of wireless charging systems by shielding metal components from excessive magnetic fields.
Implementation Method 1
the magnetic sheet has a first magnetic permeability value, and the second magnetic sheet has a second magnetic permeability value different from the first magnetic permeability value
Implementation Method 2
The transmitting terminal converts a direct current voltage into an alternating current that generates an alternating magnetic field through the coil in the transmitting terminal
Implementation Method 3
The receiving terminal couples to the alternating magnetic field to induce a corresponding alternating voltage that is then converted into a direct current voltage by a rectifying circuit to charge an electronic device
Data Source
AI summary
Provided are an electromagnetic shield device, a wireless charging transmitting terminal, a wireless charging receiving terminal and a system. By providing an electromagnetic shielding device between a power transmitting coil and a power receiving coil and making a magnetic sheet comprised in the electromagnetic shielding device not cover the power receiving coil, the magnetic field acting on the metal material is reduced on one hand and the coupling coefficient between the power transmitting coil and the power receiving coil is increased on the other hand, which reduces the intensity of the emitted magnetic field without changing the required voltage. This reduces an amount of heat and loss during wireless charging and improves charging efficiency.