Permanent Magnet Rotor Segmentation for Eddy Current Reduction
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Solution Overview
Problem
High-speed or large-sized permanent magnet rotating electric machines face efficiency decreases due to eddy currents and thermal stress issues, with existing solutions like insulating materials between magnets causing additional problems such as breakage and increased manufacturing costs.
Innovation Solution
The solution involves arranging permanent magnets with different magnetic pole directions on a rotor iron core without insulating materials between magnet pieces, allowing for reduced eddy current loss and stress relaxation, using organic solvent-free insulators that maintain integrity at high temperatures and in vacuums, and employing magnet pieces that can be divided and fixed without interposing substances to reduce manufacturing complexity and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If insulating materials are interposed between permanent magnet pieces, then eddy current loss is reduced, but manufacturing complexity and cost increase due to uniform disposition requirements
Solution Approach 1:
The permanent magnet is divided into multiple magnet pieces arranged side by side in the circumferential direction. The segmentation itself creates magnetic pole differences between adjacent pieces, which reduces eddy current paths without requiring additional insulating materials between pieces.
Solution Approach 2:
The insulating material layer is completely removed from between magnet pieces. Instead of using insulating materials to reduce eddy current, the invention extracts this component entirely and achieves eddy current reduction solely through the magnetic pole direction differences created by segmentation.
2Loss of energy
If insulating materials are used between magnet pieces, then eddy current is decreased, but stress and breakage occur due to thermal expansion differences
Solution Approach 1:
The magnet is segmented into multiple pieces with alternating magnetic pole directions. This segmentation reduces eddy current paths inherently, eliminating the need for insulating materials that would cause thermal expansion stress and potential breakage.
Solution Approach 2:
The insulating material is extracted/removed from the structure. By eliminating this component, the source of thermal expansion stress and breakage is removed, while eddy current reduction is achieved through the magnetic pole differences of segmented pieces.
3Loss of energy
If insulating members are disposed between magnet pieces, then eddy current is reduced, but manufacturing time and cost increase
Solution Approach 1:
The permanent magnet is segmented into multiple pieces that are directly arranged side by side without insulating members. This segmentation reduces eddy current while simplifying manufacturing by eliminating the steps of selecting, positioning, and securing insulating materials between pieces.
Solution Approach 2:
The insulating members are completely removed from the manufacturing process. This extraction eliminates the time-consuming steps of uniformly disposing insulating members between magnet pieces, thereby improving manufacturing efficiency while maintaining eddy current reduction through magnetic pole differences.
4Loss of energy
If insulating members are placed between magnet pieces, then eddy current loss is decreased, but magnet properties are reduced
Solution Approach 1:
The magnet is segmented into pieces with alternating magnetic pole directions, which reduces eddy current paths. This segmentation approach decreases eddy current loss without introducing insulating members that would interfere with magnetic flux and reduce magnet properties.
Solution Approach 2:
Insulating members are extracted from the structure, eliminating their negative impact on magnetic properties. Eddy current reduction is achieved purely through the magnetic pole direction differences of segmented pieces, preserving full magnet performance.
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 loss, prevents heat damage, and decreases manufacturing time and costs, while maintaining magnetic performance across varying temperatures and environments.
Implementation Method 1
using permanent magnets to generate a field magnetic flux
Implementation Method 2
a decrease in efficiency is caused by an eddy current generated in magnets
Data Source
AI summary
The present invention provides a rotating electric machine in which damage to a magnet from heat is prevented, eddy current loss is reduced while decreasing an eddy current generated in a permanent magnet, and furthermore, time and cost for manufacturing can be reduced. The present invention provides a permanent magnet rotating electric machine comprising a stator having a plurality of salient stator poles wound with windings; and a rotor separated from the stator by a rotation air gap and held rotatably, wherein the rotor may comprise a rotor iron core having therein a plurality of permanent magnet insertion holes annularly arranged side by side at a distance from one another in a circumferential direction of the rotor; and permanent magnets inserted into the plurality of permanent magnet insertion holes such that the permanent magnets in the insertion holes adjacent to each other along the circumferential direction of the rotor have different magnetic pole directions from each other, and wherein the permanent magnets each may comprise a plurality of magnet pieces arranged side by side and may have a structure in which nothing is interposed between the magnet pieces.