Rotor Magnet Layer Layout for Sinusoidal Flux and Torque Density
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Solution Overview
Problem
Existing electric machines face challenges in improving torque density and efficiency, which affects vehicle range and performance.
Innovation Solution
A rotor assembly design featuring a specific arrangement of magnets with overlapping layers and acute angles to control magnetic flux, creating a sinusoidal magnetic flux distribution in the air gap, enhancing the operating characteristics of the electric machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional magnet arrangements are used, then the structure is simple, but torque density and efficiency are limited
Solution Approach 1:
The rotor pole is segmented into multiple magnet layers (first magnet layer with central first magnet, second magnet layer with inclined second magnets, and optionally third magnet layer with inclined third magnets). Each layer contains magnets with specific orientations and positions, dividing the magnetic flux control function across multiple segments to achieve sinusoidal distribution and improved torque density
Solution Approach 2:
The patent introduces a radial dimension by arranging magnets in multiple layers at different radial positions (radially outermost, radially innermost, and intermediate positions). This multi-layer radial arrangement allows control of magnetic flux in three-dimensional space, creating the desired sinusoidal distribution pattern that improves torque density
2Loss of energy
If magnets are arranged to improve magnetic flux control, then efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The magnetic flux control function is segmented across multiple layers, with each layer performing a specific function (central first magnet for primary flux, inclined second magnets for flux shaping, inclined third magnets for fine-tuning). This segmentation allows optimized efficiency while organizing manufacturing into discrete, manageable assembly steps
Solution Approach 2:
The magnet layers are arranged in a nested configuration where the second magnet layer is radially inset from the first magnet layer, and the third magnet layer is disposed between them. This nesting allows compact assembly and systematic manufacturing procedures, reducing overall complexity despite the multi-layer structure
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 proposed magnet arrangement improves magnetic flux continuity and efficiency, leading to enhanced torque density and overall performance of the electric machine.
Implementation Method 1
control the magnetic flux in the air gap between the rotor assembly and the stator assembly
Implementation Method 2
a plurality of magnets, the magnets being configured to form a plurality of rotor poles
Data Source
AI summary
A rotor assembly for an electric machine has a rotor and magnets configured to form rotor poles that each have a central pole axis extending in a radial direction from a longitudinal axis. The rotor poles each have a first magnet layer having one or more first magnet including a central first magnet having a first transverse axis disposed perpendicular to the central pole axis. The rotor poles each have a second magnet layer radially inset from the first magnet layer and having two or more second magnets that include a pair of inclined second magnets each having a first transverse axis extending at an acute angle to the central pole axis. In relation to the central pole axis, a portion of each inclined second magnet is disposed inboard of an end of the central first magnet.