Axial Flux Pole Piece Structure for Better Flux Use and Manufacturability
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Solution Overview
Problem
Existing axial flux electric machines underutilize the flux carrying capacity of electrical steel and magnetic flux of permanent magnets, and manufacturing trapezoidal shaped pole pieces is challenging due to limitations in standard electrical steel punching and joining methods, while soft magnetic composites achieve lower saturation levels.
Innovation Solution
The use of conductive ribbons, including soft magnetic and insulative materials, coiled in an interleaved composite material coil to form pole pieces, which are free-standing and distributed over the entire surface area, eliminating the need for complex manufacturing processes and enhancing magnetic flux utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard electrical steel punching and joining methods are used to manufacture trapezoidal shaped pole pieces, then manufacturing complexity is reduced, but manufacturing precision and structural integrity deteriorate
Solution Approach 1:
The patent employs composite construction by winding conductive ribbons around a pole piece core, creating a hybrid structure that combines the magnetic properties of electrical steel with the conductive properties of ribbon windings. This composite approach eliminates the need for complex punching and joining operations while achieving superior structural integrity and electrical connectivity.
Solution Approach 2:
The invention transitions from solid block pole pieces to ribbon-based wound structures, fundamentally changing the geometric and structural parameters. This parameter transformation allows for simplified manufacturing through winding operations while maintaining or enhancing structural integrity through the distributed nature of the ribbon construction.
2Ease of manufacture
If soft magnetic composites are used to form pole pieces, then manufacturing ease is improved, but magnetic flux carrying capacity deteriorates due to lower saturation levels
Solution Approach 1:
The patent creates a composite structure where traditional electrical steel provides the high saturation magnetic flux capacity, while conductive ribbons provide simplified manufacturing and enhanced electrical connectivity. This composite approach allows the system to achieve both ease of manufacture and high magnetic flux capacity by leveraging the strengths of different materials.
Solution Approach 2:
The pole piece is segmented into distinct functional components: the electrical steel core that carries magnetic flux and the conductive ribbons that provide electrical connectivity. This segmentation allows each component to be optimized for its specific function, with the steel core maintaining high flux capacity and the ribbons enabling simplified manufacturing.
3Ease of manufacture
If conductive ribbons are coiled in an interleaved composite material coil to form free-standing pole pieces, then manufacturing cost and weight are reduced, but structural complexity increases
Solution Approach 1:
The conductive ribbons are configured to be self-supporting and self-aligning within the pole piece structure. The interleaved winding pattern allows the ribbons to automatically position themselves during the winding process, eliminating the need for complex assembly operations and reducing manufacturing costs despite the apparent structural complexity.
Solution Approach 2:
The patent employs curved and rounded geometries in the ribbon windings, allowing for continuous winding operations that are simpler and more cost-effective than straight-line constructions. The curved paths of the ribbons naturally distribute stresses and simplify the winding process, reducing manufacturing complexity despite the three-dimensional nature of the structure.
4Reliability
If conventional coil windings are used around trapezoidal pole pieces, then electrical connectivity is maintained, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the functions of structural support and electrical connectivity into a single integrated ribbon winding structure. The conductive ribbons simultaneously provide mechanical support for the pole piece and establish electrical connections, eliminating the need for separate winding operations and reducing manufacturing complexity while maintaining reliable electrical connectivity.
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 reduces electrical machine losses, increases efficiency, and allows for a low-cost manufacturing process by utilizing the full magnetic flux capacity of the materials, while providing flexibility in design and reducing weight and manufacturing costs.
Implementation Method 1
The coiled ribbon of conductive material forms at least part of a pole piece in the plurality of pole pieces
Implementation Method 2
The soft magnetic material is what allows the device to be configurably magnetized under the influence of current applied to the coiled wire
Data Source
AI summary
Axial flux electric machines and associated methods are disclosed herein. One disclosed axial flux electric machine includes a stator having a plurality of pole pieces, a rotor spaced apart from the stator in an axial direction of the axial flux electric machine, and a coiled ribbon of conductive material forming at least part of a pole piece in the plurality of pole pieces. An axial direction of the coiled ribbon of conductive material is substantially parallel to the axial direction of the axial flux electric machine. In some embodiments of the disclosed axial flux electric machine a coiled ribbon of soft magnetic material is coiled with a coiled ribbon of conductive material into an interleaved composite material coil which forms at least part of a pole piece for an axial flux electric machine.