Laminated Permanent Magnet Rotor Body for Lower Eddy Current Loss
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Solution Overview
Problem
The manufacturing process of large wind turbine generators with steel rotor bodies is becoming expensive and inefficient due to welding challenges, eddy current losses, heat generation, and increased rare earth metal content, leading to reduced flux density and performance.
Innovation Solution
A laminated rotor structure composed of stacked lamination sheets with integrated permanent magnets and tensioning bolts, eliminating machining and baseplate requirements, and incorporating insulation layers to reduce eddy current losses and cooling features to manage temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a steel rotor body is used, then structural strength is improved, but eddy current losses and heat generation increase
Solution Approach 1:
The rotor body is segmented into multiple thin lamination sheets stacked together, which interrupts the path for eddy currents while maintaining structural integrity. This segmentation reduces eddy current losses without compromising the overall strength of the rotor body.
Solution Approach 2:
The rotor body uses a composite structure combining laminated steel sheets with non-conductive insulation layers between them. This composite approach maintains mechanical strength while minimizing electrical conductivity paths that cause eddy current losses.
2Stability of the object's composition
If welding is used to manufacture the rotor body, then structural integrity is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The rotor body is manufactured by stacking pre-formed lamination sheets together, eliminating the need for complex welding operations. The segmentation into discrete sheets simplifies manufacturing while maintaining structural integrity through the stacking and compression process.
Solution Approach 2:
Multiple lamination sheets are combined into a single rotor body structure through stacking and compression, achieving structural integrity without welding. The insulation layers between sheets are integrated into the stacking process, merging multiple functions into a single manufacturing operation.
3Power
If the rotor size is increased, then power output is improved, but manufacturing difficulty and cost increase
Solution Approach 1:
The rotor body is constructed from multiple standard-sized lamination sheets that can be stacked to achieve any desired rotor size. This segmentation allows scalable manufacturing where larger rotors are simply formed by adding more sheets rather than requiring custom large-scale welding operations.
Solution Approach 2:
The lamination sheets are prepared and insulated beforehand before stacking, allowing parallel manufacturing of components. This preliminary preparation simplifies the final assembly process and enables standardized manufacturing procedures that can be scaled to produce rotors of various sizes.
4Reliability
If permanent magnets are placed in machined pockets, then magnet retention is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The rotor body is segmented into lamination sheets with pre-formed slots that accommodate permanent magnets. This segmentation eliminates the need for complex machining operations on the finished rotor, as the magnet-receiving features are created during the lamination sheet fabrication process.
Solution Approach 2:
The slots for permanent magnets are prepared in advance during the lamination sheet manufacturing process, before the rotor is fully assembled. This preliminary action eliminates the need for post-assembly machining and simplifies the magnet installation process.
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
Reduces production costs, minimizes eddy current losses, lowers permanent magnet operating temperatures, and enhances flux density while reducing the need for heavy rare earth metals.
Implementation Method 1
the rotor body is made of steel, and this leads to eddy current losses and heat generation during operation
Implementation Method 2
The laminations structure of the rotor body according to embodiments of the invention allow eliminating expensive machining processes
Data Source
AI summary
A rotor for an electrical machine extends along a longitudinal axis between a drive end and an axially opposite non-drive end, the drive end being attachable to a torque input. The rotor includes: a rotor body extending axially between the drive end and the non-drive and extending in a radial direction orthogonal to the longitudinal axis between an inner side and an outer side, plurality of permanent magnets attached to the inner side a circumferentially distributed about the longitudinal axis, wherein the rotor body includes a plurality of lamination sheets stacked along the longitudinal axis.