Flux-Directed Magnet Assemblies Without Back Iron for High Torque Density
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Solution Overview
Problem
Existing electric machines face limitations in power and torque densities due to the weight and saturation of back iron, manufacturing complexity, and high costs of Halbach arrays, which hinder their widespread use in applications requiring high efficiency and compact designs.
Innovation Solution
The integration of discrete Flux-Directed Magnetic (FDM) assemblies, which eliminate back iron by using opposing flux-channeled magnetic segments, optimize flux density, and reduce manufacturing complexity, enabling higher power and torque densities through improved flux channeling designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If back iron is used in conventional electric machines, then magnetic flux can be contained and directed, but the weight increases and saturation limits the flux density to below 2 Tesla
Solution Approach 1:
The patent extracts and eliminates the back iron component from the electric machine design by using opposing flux-channeled magnetic segment arrays that contain and direct magnetic flux without requiring a back iron structure. This removal of unnecessary components directly reduces weight while maintaining flux containment through the magnetic segment arrangement.
Solution Approach 2:
The patent uses composite magnetic segment arrays with opposing flux channeling properties to replace the homogeneous back iron structure. The composite arrangement of magnetic segments with specific orientations creates equivalent flux containment functionality while avoiding the weight and saturation limitations of conventional back iron.
2Power
If Halbach arrays are used to achieve high flux density, then power density can be increased, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent divides the magnetic field generation into discrete, modular magnetic segments arranged in opposing arrays. Each segment is independently manufacturable with standardized geometry, eliminating the need for complex continuous Halbach array manufacturing while achieving similar flux concentration effects through the segmented structure.
Solution Approach 2:
The patent changes the manufacturing parameters from complex continuous magnetization patterns required for Halbach arrays to simpler discrete segment orientations. The opposing flux-channeled segments use straightforward magnetization directions that are easier to manufacture while maintaining the flux density enhancement needed for high power density.
3Power
If superconducting machines are used to achieve power densities of 25 kW/kg or higher, then AC losses can be accommodated at low RPMs, but the complexity of cryogenics and quench detection increases
Solution Approach 1:
The patent replaces the complex cryogenic and quench detection systems required for superconducting machines with a purely magnetic field-based solution using opposing flux-channeled segments. This substitution achieves high power density through magnetic flux optimization rather than superconducting physics, eliminating the need for cryogenics infrastructure.
4Loss of energy
If magnetic gear boxes are integrated with electric machines, then efficiency in energy conversion and transmission improves, but device complexity increases
Solution Approach 1:
The patent merges the magnetic gear box functionality directly into the electric machine structure by integrating opposing flux-channeled magnetic segment arrays that simultaneously provide both motor/generator operation and magnetic gearing. This consolidation eliminates separate magnetic gear box components while maintaining the efficiency benefits of direct magnetic coupling for energy conversion and transmission.
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 approach achieves unprecedented power and torque densities in synchronous machines, with reduced manufacturing costs and increased efficiency, making them suitable for applications like aircraft propulsion and wind power generation.
Implementation Method 1
John C. Mallinson, a British-American physicist, published a magnetic theory for a new class of magnetization patterns for planar structures in which the magnetization direction is a spatially rotating flux with constant amplitude. Such an ordered array of permanent magnet elements augments the magnetic field on one side of the array while canceling the field to near zero on the other side of the array.
Implementation Method 2
An application of flux channeling with assemblies of magnetic elements is exemplified in the Halbach Array, invented by Klaus Halbach in 1980 for charged particle beam optics in accelerators and corresponding beam lines.
Implementation Method 3
The integration of discrete Flux-Directed Magnetic (FDM) assemblies, which eliminate back iron by using opposing flux-channeled magnetic segments, optimize flux density, and reduce manufacturing complexity, enabling higher power and torque densities through improved flux channeling designs.
Data Source
AI summary
A magnetic array for use in a synchronous electrical machine or a magnetic gear box, comprising a plurality of discrete magnetic segments. When individual ones of the segments are spaced away from influence of ferromagnetic material, such as prior to placement in the array, each includes a pole having the same maximum field strength. Each segment is positioned in a sequence along a circumferential array with changes in field orientation by which the field of each segment is spatially rotated relative to the field of a next segment in the sequence. Each segment is positioned in sufficient proximity to the next segment in the sequence to enable the fields to interact with one another and effect flux channeling.