Rotor Winding Structure for Permanent Magnet Heat Isolation

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Solution Overview

Problem

The heat generated in rotor windings of rotating electric machines transfers to permanent magnets, reducing their magnetic force and resulting in decreased output.

Innovation Solution

Incorporating non-magnet portions made of magnetic or non-magnetic members within the rotor windings, which are fixed to the rotor core, allowing the windings to be separate from the permanent magnets, thereby reducing heat transfer and maintaining magnetic force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If rotor windings are closely integrated with permanent magnets in the rotor core, then the device complexity is reduced and manufacturing is simplified, but heat generated in the rotor windings transfers to the permanent magnets causing temperature rise and magnetic force degradation

Engineering Contradiction:
Improvestructural complexityVSAvoidtemperature of permanent magnets
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The rotor structure is segmented into distinct functional zones: a non-magnetic portion that houses the rotor windings and a magnetic portion that contains the permanent magnets. This spatial segmentation physically separates the heat-generating windings from the temperature-sensitive permanent magnets, preventing thermal degradation while maintaining structural organization and simplifying manufacturing processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A non-magnetic portion acts as an intermediary barrier between the rotor windings and permanent magnets. This intermediary structure provides thermal isolation, blocking heat transfer from the windings to the permanent magnets, while still allowing the rotor to function as an integrated electromagnetic device.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If rotor windings are supplied with high current to increase output, then the power output increases, but heat generation in the rotor windings increases causing temperature rise and magnetic force reduction of permanent magnets

Engineering Contradiction:
Improveoutput powerVSAvoidmagnetic force stability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

By segmenting the rotor into non-magnetic and magnetic portions, the patent enables high current operation in the windings without compromising permanent magnet performance. The spatial separation allows the windings to handle high currents for increased power output while the permanent magnets remain thermally protected, maintaining magnetic force stability even under high-load conditions.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If rotor windings are fixed directly to the rotor core, then the ease of manufacture is improved, but the heat transfer path from windings to permanent magnets is shortened causing temperature rise

Engineering Contradiction:
Improvemanufacturing easeVSAvoidheat transfer to permanent magnets
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The rotor is manufactured as a segmented structure with distinct non-magnetic and magnetic portions. The non-magnetic portion is designed to house the windings and is positioned between the windings and permanent magnets, providing thermal isolation. This segmentation maintains manufacturing simplicity while effectively blocking harmful heat transfer to the permanent magnets.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The non-magnetic portion serves as an intermediary structure that simplifies manufacturing by providing a dedicated housing for the windings, while simultaneously functioning as a thermal barrier that prevents heat from reaching the permanent magnets, thus eliminating the trade-off between manufacturing ease and thermal protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration suppresses the reduction in output by maintaining the thermal demagnetization resistance of the permanent magnets and improving the productivity and efficiency of the rotating electric machine.

Implementation Method 1

each of the rotor winding portions includes a non-magnet portion formed of a magnetic member other than a permanent magnet or a non-magnetic member... the rotor windings are fixed to the rotor core through intermediation of the non-magnet portions

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3910768B1Rotating electric machine rotor
Publication Date: 2024.06.05 MITSUBISHI ELECTRIC CORP
  • EP3910768B1 patent drawingFigure 1~2
  • EP3910768B1 patent drawingFigure 3~4
  • EP3910768B1 patent drawingFigure 5~6

AI summary

Provided is a rotor for a rotating electric machine, which enables suppression of a reduction in output of a rotating electric machine. The rotor for a rotating electric machine includes: a rotor core (34) having winding-portion insertion holes (341) and magnet insertion holes (342); rotor winding portions (35) inserted into the winding-portion insertion holes (341); and rotor permanent magnets (36) inserted into the magnet insertion holes (342), wherein each of the rotor winding portions (35) includes: a non-magnet portion (351); and a rotor winding (352) provided to the non-magnet portion (351), wherein each of the non-magnet portions (351) is fixed to the rotor core (34), and wherein the rotor windings (352) are fixed to the rotor core (34) through intermediation of the non-magnet portions (351).