Inductive Power Transmission Through Saturated Magnetic Steel Barrier
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Solution Overview
Problem
Inductive power and data transfer becomes inefficient when a barrier layer includes electrically conductive materials like magnetic steels, as these materials absorb or reflect electromagnetic energy, reducing power transfer efficiency and data signal levels, making it impractical for applications such as powering sensors through steel in automotive, aerospace, and other industries.
Innovation Solution
A wireless power transmission system is implemented using a DC bias field to saturate the magnetization of a permeable conductive barrier layer, increasing the skin depth and enhancing power transfer efficiency and data signal levels by employing a primary coil on one side of the barrier to transmit power and data, and a secondary coil on the other side to receive, with the option to send data back using load modulation or other communication schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If inductive power transfer is used through a conductive barrier layer, then power can be transmitted wirelessly, but the conductive material absorbs or reflects electromagnetic energy, reducing power transfer efficiency
Solution Approach 1:
The patent applies a DC bias field to saturate the magnetic steel barrier layer, fundamentally changing its magnetic properties. By driving the material into magnetic saturation, the effective permeability is reduced, which decreases the skin depth effect and allows electromagnetic energy to penetrate more effectively through the conductive barrier, thereby improving power transfer efficiency
Solution Approach 2:
A DC bias field is introduced as an intermediary element that modifies the properties of the barrier layer. This bias field acts as a mediator that changes the magnetic steel's characteristics to be more permeable to the AC power transfer field, enabling efficient energy transmission through what would otherwise be a blocking barrier
2Strength
If a conductive barrier layer is present, then mechanical protection and structural integrity are provided, but the barrier absorbs or reflects electromagnetic energy, reducing data signal levels
Solution Approach 1:
By applying a DC bias field to saturate the magnetic steel barrier, the patent changes the magnetic parameters of the material. This saturation reduces the effective permeability seen by the AC data signals, allowing them to penetrate the barrier more effectively and maintain sufficient signal levels for reliable data communication
3Ease of manufacture
If magnetic steel is used as the barrier material, then excellent mechanical properties and low cost are achieved, but the combination of conductivity and permeability substantially reduces the skin depth
Solution Approach 1:
The patent changes the operational state of the magnetic steel by applying a DC bias field that drives it into saturation. This parameter change effectively increases the skin depth for AC signals by reducing the material's effective permeability at the operating frequency, allowing electromagnetic energy to penetrate deeper through the steel barrier
Solution Approach 2:
The DC bias field is applied in advance to pre-saturate the magnetic steel barrier before AC power and data signals are transmitted. This preliminary action modifies the barrier's properties to be more favorable for AC signal penetration, effectively increasing the skin depth before the actual power transfer occurs
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 system significantly improves power transfer efficiency and data rate through permeable conductive materials like magnetic steel by increasing the skin depth, allowing for effective power and data transmission across conductive barriers, suitable for various industrial applications including sensor powering and RFID tagging.
Implementation Method 1
a DC bias field is added to an AC inductive power and/or data transfer field in order substantially to saturate the barrier material and reduce its effective permeability
Implementation Method 2
the combination of conductivity and permeability substantially reduces the thickness through which electromagnetic energy of a given frequency will penetrate (which thickness is conventionally referred to as the 'skin depth' of the material at that frequency)
Implementation Method 3
An alternating current is passed through a primary coil on the one side of the barrier. The mutual inductance between the coils means that an emf is induced in the secondary coil on the other side of the gap
Data Source
AI summary
A wireless power transmission system is designed to transmit power through a permeable conductive barrier layer. The system comprises a power transmitting circuit including a first inductive coil. A power receiving circuit includes a second inductive coil located on the opposite side of the barrier layer to the first inductive coil. A biasing magnet or electromagnet is provided and characterised by its ability to substantially saturate the magnetisation of the barrier layer in a region adjacent to the first and second inductive coils.