Wound Rotor Cooling Circuit with Targeted Winding Fluid Outlets

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Solution Overview

Problem

Existing cooling methods for electric motors, such as spraying cooling fluid, do not effectively dissipate heat from stator and rotor windings, leading to increased fluid consumption and inefficiency.

Innovation Solution

A wound rotor design with internal channels for cooling fluid circulation and radial, intermediate, and axial fluid outlets that directly project cooling fluid onto stator windings, enhancing heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cooling fluid is sprayed inside the motor to cool windings, then heat dissipation is improved, but cooling fluid consumption increases

Engineering Contradiction:
Improveheat dissipationVSAvoidcooling fluid consumption
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The cooling system is segmented into multiple independent channels: a first cooling channel for rotor windings, a second cooling channel for stator windings, and a third cooling channel for the bearing assembly. This segmentation allows targeted cooling of each component, improving heat dissipation efficiency while reducing overall cooling fluid consumption by avoiding unnecessary cooling of already-cooled areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different cooling strategies are applied to different locations based on their specific thermal requirements. The rotor windings receive cooling through channels formed by laminations, the stator windings receive cooling through a dedicated second channel, and the bearing assembly receives cooling through a separate third channel. This localized approach ensures optimal cooling efficiency for each component while minimizing total fluid consumption.

Inventive Principle:
Principle #3Local quality

2Temperature

If cooling fluid is sprayed directly onto windings, then heat dissipation is improved, but device complexity increases

Engineering Contradiction:
Improveheat dissipationVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling system merges multiple cooling functions into an integrated structure. The first cooling channel is formed by the lamination package itself, combining the rotor structure with the cooling function. The second and third channels are integrated into the same cooling fluid circulation system, allowing a single pump and fluid supply to serve multiple cooling purposes, thereby reducing overall system complexity while achieving direct cooling of all windings.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooling fluid circulation system serves multiple functions simultaneously: it cools the rotor windings through the first channel, cools the stator windings through the second channel, and cools the bearing assembly through the third channel. This multi-functional approach eliminates the need for separate cooling systems for each component, reducing device complexity while maintaining effective heat dissipation across all critical areas.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Efficient heat dissipation from both rotor and stator windings is achieved, reducing cooling fluid consumption and improving motor performance.

Implementation Method 1

the currents flowing through the stator phase windings and rotor windings generate significant heat that must be dissipated

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a cooling fluid circulating inside the rotor shaft and then inside the front and/or rear winding flange

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4416829B1Wound rotor for an electric motor provided with a cooling circuit
Publication Date: 2025.11.05 NOVARES FRANCE
  • EP4416829B1 patent drawingFigure 1~2
  • EP4416829B1 patent drawingFigure 3~4
  • EP4416829B1 patent drawingFigure 5a~5b

AI summary

The invention relates to a wound rotor (10) for an electric motor (1), comprising: - a rotor shaft (12) rotatably mounted about an axis (X); - rotor laminations (14) mounted coaxially on the rotor shaft (12), said rotor laminations (14) having alternating poles and interpolar spaces; - a front winding flange (15) and a rear winding flange (15') mounted coaxially on the rotor shaft (12) and arranged axially on either side of the rotor laminations (14); - windings (16) partially surrounding the poles (141) of the rotor laminations (14) and the front and rear winding flanges (15, 15'); wherein a plurality of fluid flow channels pass through the front winding flange (15) and/or the rear winding flange (15'), through which flow channels a cooling fluid can flow.