Halbach Array Magnet Configuration for Wireless Power Transfer
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Solution Overview
Problem
Wireless power transfer systems face inefficiencies due to stray magnetic fields, which induce heat in nearby metallic objects and reduce power transfer efficiency, and existing technologies struggle to concentrate magnetic fields effectively between the transmitter and receiver.
Innovation Solution
A magnetically coupled wireless power transfer system utilizing rotating magnets with Halbach arrays and stationary coils, where the magnets' magnetization directions are angularly offset to concentrate magnetic fields within the air gap, reducing stray fields and enhancing power transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional coils or simple magnet arrangements are used in wireless power transfer systems, then the system structure is simple, but the magnetic field is not concentrated and stray fields cause energy loss and safety concerns
Solution Approach 1:
The magnetic field generating system is divided into multiple discrete magnetic field generating units, each with specifically oriented magnets. This segmentation allows independent optimization of each unit's magnetic field contribution, enabling concentrated fields in the air gap while canceling stray fields in surrounding areas, thus improving power transfer efficiency without requiring overly complex integrated structures
Solution Approach 2:
Different regions of the magnetic field generating units have different magnet orientations and configurations. The magnets are arranged with specific polarities facing the air gap to concentrate flux where needed, while opposite polarities are positioned to cancel stray fields. This local differentiation of magnetic properties optimizes energy transfer while minimizing losses
2Power
If strong magnetic fields are generated for effective power transfer, then power transfer efficiency improves, but stray magnetic fields increase causing safety concerns and energy loss
Solution Approach 1:
The magnetic field generating units employ asymmetric magnet arrangements where the polarity distribution is not uniform in all directions. Stronger magnetic fields are deliberately concentrated toward the air gap for effective power transfer, while weaker or canceling fields are directed away from surrounding areas. This asymmetric configuration achieves high power transfer without proportionally increasing harmful stray fields
Solution Approach 2:
The system converts what would normally be wasted stray magnetic fields into beneficial concentrated fields. By strategically positioning magnets with alternating polarities, the fields that would otherwise radiate outward and cause losses are redirected and concentrated into the air gap, transforming potential harm into useful energy transfer
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 effectively increases the magnetic field strength between the transmitter and receiver, improving power transfer efficiency while minimizing stray magnetic fields, thus enhancing safety and reducing energy loss.
Implementation Method 1
A time-varying current flows in the transmitter coil, which produces a time-varying magnetic field. This time-varying magnetic field induces current in the nearby receiver coil (Faraday's law)
Implementation Method 2
the magnets' magnetization directions are angularly offset to concentrate magnetic fields within the air gap, reducing stray fields and enhancing power transfer efficiency
Implementation Method 3
The technology may make use of a strong magnetic coupling whereby a rotating magnet in a wireless power transmitter couples onto another nearby magnet in the wireless power receiver. The transfer of energy is via rotational magnetic coupling rather than direct magnetic induction mechanism
Data Source
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AI summary
Wireless power transfer systems comprising of special arrangements of magnetic field generating materials within the wireless power transmitter and the wireless power receiver. The arrangement enables a greater amount of the magnetic field to be contained within the air gap between the wireless power transmitter and the wireless power receiver than outside of the air gap.