Halbach Array Electric Motor for Large Air Gaps
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Solution Overview
Problem
Conventional electric motors face challenges in maintaining sufficient magnetic field strength over larger distances due to the weakness of magnetic fields from conventional electromagnets and permanent magnets, which limits their design flexibility and increases weight, especially in harsh environments where weight savings are crucial.
Innovation Solution
The use of Halbach arrays for both magnets and electromagnets, allowing for a high flux density in gaps between them, enabling larger gaps while maintaining efficiency through matching flux densities and armature power, and a controller to selectively direct current through coils to induce interacting magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional electromagnets or permanent magnets are used, then magnetic field strength is sufficient at very small distances, but the distance between magnets must be kept very small which negatively impacts design flexibility and reliability in harsh environments
Solution Approach 1:
The patent applies asymmetry by using Halbach arrays where magnets are arranged with specific asymmetric orientations (e.g., alternating polarities at 45-degree angles) to concentrate magnetic flux in one direction while canceling it in another. This asymmetric configuration allows the magnetic field to maintain strength over larger distances compared to conventional symmetric arrangements.
Solution Approach 2:
The patent changes the spatial arrangement parameter of magnets from conventional patterns to Halbach array configurations, where the orientation angle and position of each magnet are specifically optimized to enhance flux concentration. This parameter optimization enables larger air gaps while maintaining sufficient magnetic coupling.
2Length of stationary object
If iron-cored electromagnets are used to increase magnetic field strength and allow greater distances between magnets, then the distance between magnets can be increased, but the weight of the electric motor significantly increases
Solution Approach 1:
The patent extracts the iron core from the electromagnet design, using only the coil windings to generate magnetic fields. By removing the heavy iron core and relying on Halbach arrays of permanent magnets to provide the magnetic field concentration, the system achieves the same functional effect with significantly reduced weight.
Solution Approach 2:
The patent replaces the mechanical/physical structure of iron cores with an electromagnetic field-based solution using Halbach arrays. The magnetic flux concentration is achieved through the geometric arrangement and magnetization orientation of permanent magnets rather than through ferromagnetic materials, substituting a field-based mechanism for a material-based one.
3Reliability
If tight tolerances are maintained between magnets to ensure sufficient magnetic field strength, then magnetic field strength is adequate, but the motor becomes unsuitable for harsh environments where dust or sand may become lodged
Solution Approach 1:
The patent segments the magnetic system into two distinct components: permanent magnets arranged in Halbach arrays that provide the magnetic field, and coil windings that selectively interact with this field. This segmentation allows for larger gaps between components, making the system tolerant to environmental contaminants while maintaining functional performance.
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 configuration allows for larger gaps between magnetic components without significantly increasing the motor's weight, enhancing efficiency and suitability for harsh environments by maintaining high magnetic field strength and torque, particularly beneficial in space-bound and dusty conditions.
Implementation Method 1
a first plurality of magnets arranged in a first Halbach array, wherein the first plurality of magnets is configured to provide a first magnetic field that substantially exhibits a first Halbach flux distribution
Implementation Method 2
the first plurality of magnets is configured to provide a first magnetic field
Implementation Method 3
a controller adapted to selectively direct current through the first plurality of coils to induce a second magnetic field to interact with the first magnetic field
Implementation Method 4
a first plurality of electromagnets comprising a first plurality of coils arranged in a second Halbach array; and a controller adapted to selectively direct current through the first plurality of coils to induce a second magnetic field to interact with the first magnetic field
Implementation Method 5
the second magnetic field to interact with the first magnetic field
Data Source
AI summary
Electric motor configurations are provided with Halbach arrays. In one example, an electric motor includes a first plurality of magnets arranged in a first Halbach array. The first plurality of magnets is configured to provide a first magnetic field that substantially exhibits a first Halbach flux distribution. A first plurality of electromagnets comprising a first plurality of coils are arranged in a second Halbach array. A controller is adapted to selectively direct current through the first plurality of coils to induce a second magnetic field to interact with the first magnetic field. The second magnetic field substantially exhibits a second Halbach flux distribution.