Selectively Controllable Electromagnetic Shield for Wireless Power

Solution Overview

Problem

Conventional wireless power transfer systems face challenges in providing positional freedom and controlling electromagnetic field broadcast, leading to inefficiencies and parasitic heating, especially in wide surface area charging systems that power multiple devices simultaneously.

Innovation Solution

A selectively controllable electromagnetic shield that can be saturated to create apertures, allowing magnetic fields to penetrate only where needed, while maintaining shielding properties elsewhere, using magnetic materials with high permeability and controlled saturation to manage magnetic flux.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a large primary coil is used to provide increased spatial freedom for device placement, then positional freedom is improved, but stray electromagnetic fields and parasitic losses increase

Engineering Contradiction:

Improvepositional freedomVSAvoidparasitic losses

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The magnetic shield is divided into multiple independently controllable segments or regions. Each segment can be selectively saturated to create localized apertures, allowing the system to provide spatial freedom only in regions where devices are actually placed, rather than across the entire large coil area. This segmentation enables precise control of magnetic flux paths to match actual device positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shield transitions from having uniform properties across its entire surface to having locally differentiated properties. By applying magnetic saturation selectively to specific regions of the shield, the system creates local apertures with different magnetic permeability characteristics compared to the surrounding unsaturated regions. This local quality change allows magnetic fields to penetrate only where needed while maintaining shielding elsewhere.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If a large primary coil is used to provide increased spatial freedom for device placement, then positional freedom is improved, but stray electromagnetic fields increase

Engineering Contradiction:

Improvepositional freedomVSAvoidstray electromagnetic fields

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The magnetic shield is divided into multiple independently controllable segments or regions. Each segment can be selectively saturated to create localized apertures, allowing the system to provide spatial freedom only in regions where devices are actually placed, rather than across the entire large coil area. This segmentation enables precise control of magnetic flux paths to match actual device positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shield utilizes magnetic saturation—a phenomenon that normally represents a loss of shielding effectiveness—as a beneficial mechanism to create controlled apertures. By deliberately saturating specific regions of the shield, the system converts what would normally be considered a degradation of shield performance into a useful feature that enables selective magnetic field penetration and spatial freedom.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If shielding materials are used to limit electromagnetic fields, then parasitic heating is reduced, but spatial freedom for device placement is restricted

Engineering Contradiction:

Improveparasitic heatingVSAvoidspatial freedom

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The magnetic shield transitions from a static, permanently shielding structure to a dynamic system where shielding properties can be changed in real-time. By applying magnetic fields to saturate specific regions of the shield, the system dynamically adjusts its permeability characteristics, creating temporary apertures that allow magnetic flux to pass through. This dynamic control enables the shield to adapt its properties based on device placement and power transfer requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The shield's magnetic permeability parameter is changed selectively across different regions by controlling the level of magnetic saturation. In unsaturated regions, the shield maintains high permeability to block magnetic fields and reduce parasitic heating. In saturated regions, the permeability decreases, creating apertures that allow magnetic flux to pass through. This parameter change enables the shield to provide both protection and spatial freedom as needed.

Inventive Principle:

Principle #35Parameter changes

4Productivity

If multiple coils are used to cover wide surface area for multi-device charging, then productivity is improved, but device complexity and parasitic losses increase

Engineering Contradiction:

Improvemulti-device charging capabilityVSAvoidcoil array complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The magnetic shield is divided into multiple independently controllable segments or regions. Each segment can be selectively saturated to create localized apertures, allowing the system to provide spatial freedom only in regions where devices are actually placed, rather than across the entire large coil area. This segmentation enables precise control of magnetic flux paths to match actual device positions.

Inventive Principle:

Principle #1Segmentation

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 enables efficient power transfer with increased spatial freedom for device placement and reduced parasitic losses by selectively directing magnetic fields, effectively addressing the challenges of field broadcast and heating in multi-device charging scenarios.

Implementation Method 1

In its un-saturated state, the magnetic shield has a high permeability so that it draws the electromagnetic field into itself and functions as a flux path for the magnetic field

Methodology Applied

Scientific EffectMagnetic permeability: Ferromagnetism

Implementation Method 2

a magnetic field source that generates a magnetic field of sufficient strength to substantially saturate all or a portion of the shield, thereby essentially temporarily removing its shielding properties

Methodology Applied

Scientific EffectMagnetic saturation: Magnetic Saturation

Implementation Method 3

Inductive wireless power transfer systems use electromagnetic fields to transfer power from the power supply to the remote device

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9161484B2Selectively controllable electromagnetic shielding

Publication Date: 2015.10.13 PHILIPS IP VENTURES BV

AI summary

A selectively controllable electromagnetic shield having an electromagnetic shielding material and a mechanism for selectively generating an aperture in the shield. The mechanism for selectively generating an aperture may be a magnetic field source that generates a magnetic field of sufficient strength to substantially saturate all or a portion of the shielding material. For example, a permanent magnet or DC electromagnet may be used to selectively saturate the shield. In its un-saturated state, the magnetic shield has a high permeability and functions as a flux path for the magnetic field. Once saturated, the permeability of the shield is substantially reduced so that the magnetic field lines are no longer drawn into the shield to the same degree. As a result, once saturated, a substantially greater amount of the electromagnetic field may flow through or around the shield in the saturated region.