Asymmetric Magnet Segmentation in PM Rotors for Lower Eddy Loss
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Solution Overview
Problem
Existing permanent-magnet rotors face challenges in reducing eddy-current losses while minimizing production costs and magnetic waste, as conventional segmentation methods are inefficient and increase production complexity.
Innovation Solution
The implementation of an asymmetrically segmented permanent-magnet rotor design, where segmentation occurs only in the end region facing away from the axis of rotation, along with the use of a poka yoke safeguard for accurate assembly, reduces eddy-current losses and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If permanent magnets are segmented to reduce eddy-current losses, then energy losses are reduced, but production outlay and magnetic waste increase
Solution Approach 1:
The permanent magnet is divided into multiple segments (first and second segments) with different magnetic properties. This segmentation reduces eddy-current losses by disrupting current paths while maintaining the overall magnetic field required for motor operation.
Solution Approach 2:
Different segments of the permanent magnet have different magnetic properties (e.g., different remanence values). The first segment has higher magnetic strength than the second segment. This local variation in magnetic quality allows optimization of both performance and loss reduction in specific regions without compromising overall motor function.
2Loss of energy
If permanent magnets are segmented to reduce eddy-current losses, then energy losses are reduced, but magnetic waste increases
Solution Approach 1:
The permanent magnet is divided into multiple segments (first and second segments) with different magnetic properties. This segmentation reduces eddy-current losses by disrupting current paths while maintaining the overall magnetic field required for motor operation.
Solution Approach 2:
Different segments of the permanent magnet have different magnetic properties (e.g., different remanence values). The first segment has higher magnetic strength than the second segment. This local variation in magnetic quality allows optimization of both performance and loss reduction in specific regions without compromising overall motor function.
3Loss of energy
If symmetric segmentation is used to reduce eddy-current losses, then energy losses are reduced, but production complexity increases
Solution Approach 1:
The permanent magnet features asymmetric segmentation where the first and second segments have different magnetic properties, specifically different remanence values. This asymmetric design allows for simplified manufacturing compared to symmetric segmentation, as it requires fewer precise cutting operations while still effectively reducing eddy-current losses through the disruption of current paths.
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 effectively reduces eddy-current losses with minimal impact on production costs and magnetic waste, offering a cost-optimized magnet segmentation method for permanent-magnet rotors.
Implementation Method 1
The rotor can have permanent magnets or electromagnets for constant magnetization
Implementation Method 2
The energy provided by the magnetic interaction between the stator and the rotor
Implementation Method 3
The permanent magnets are often segmented in order to reduce the eddy-current losses
Data Source
AI summary
A permanent-magnet rotor for a permanent-magnet motor includes a laminated core, receiving pockets which are formed in the laminated core, and permanent magnets which are each accommodated in segmented form in one of the receiving pockets. The permanent magnets have at least one asymmetrically segmented permanent magnet, which is segmented only in an end region which is arranged facing away from an axis of rotation of the permanent-magnet rotor.