Dielectric Coating on Stator Windings for Thermal Management

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Solution Overview

Problem

Conventional stator assemblies in electric machines face inefficiencies due to limited thermal conductivity and electrical losses, particularly in the cooling of windings, which affects the overall performance and power density of the machines.

Innovation Solution

The implementation of a dielectric coating on stator windings using electrophoretic deposition (EPD) to enhance thermal conductivity and minimize electrical losses, where the windings are inserted into slots with a dielectric slot liner, allowing for optimized phase separation and reduced need for additional insulation layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional insulation methods are used in stator windings, then electrical insulation is provided, but thermal conductivity is limited and cooling efficiency is reduced

Engineering Contradiction:
Improvecooling efficiencyVSAvoidthermal conductivity
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent applies electrophoretic deposition (EPD) to create a dielectric coating with optimized thermal and electrical properties. This process transforms the insulation material from conventional low thermal conductivity materials to a coating that maintains electrical insulation while significantly improving thermal conductivity, thereby enhancing cooling efficiency without sacrificing insulation performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The dielectric coating formed through EPD creates a composite structure on the winding surface that combines electrical insulation properties with enhanced thermal conductivity. This composite approach allows the insulation layer to serve dual functions: maintaining electrical isolation while facilitating heat dissipation from the winding to the slot liner

Inventive Principle:
Principle #40Composite materials

2Reliability

If additional insulation layers are added to stator windings, then electrical insulation is improved, but the filling ratio of conductive material in slots decreases

Engineering Contradiction:
Improveelectrical insulationVSAvoidfilling ratio
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts the insulation function from separate additional layers and integrates it directly into the dielectric coating applied to the winding surface. By forming the insulation layer through EPD during the winding manufacturing process, the need for separate insulation layers is eliminated, maintaining both electrical insulation and maximizing the filling ratio of conductive material in the slots

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the insulation function with the winding surface treatment by applying a dielectric coating directly to the windings. This consolidation eliminates the need for separate insulation layers, as the coating provides both the insulation barrier and the thermal management interface, thereby maintaining high filling ratios while ensuring electrical reliability

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If conventional coating methods are used on windings, then insulation is provided, but manufacturing complexity and processing time increase

Engineering Contradiction:
Improveinsulation performanceVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces conventional mechanical coating methods with electrophoretic deposition (EPD), an electrochemical process that deposits dielectric material onto the winding surface. This substitution provides more uniform coating thickness, better adhesion, and controlled material application, thereby improving insulation performance while simplifying the manufacturing process and reducing processing time

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 improves thermal conductivity, reduces electrical losses, and increases power density by maximizing the filling ratio of conductive material within the slots, thereby enhancing the efficiency of the electric machine.

Implementation Method 1

a dielectric coating formed by way of electrophoretic deposition (EPD)

Methodology Applied
Scientific EffectElectrophoretic deposition: Electrophoretic Deposition

Data Source

PatentEP3913774A1Method and system for thermally insulating portions of a stator core
Publication Date: 2021.11.24 GE AVIATION SYSTEMS LLC
  • EP3913774A1 patent drawingFigure 1
  • EP3913774A1 patent drawingFigure 2
  • EP3913774A1 patent drawingFigure 3

AI summary

An electric machine stator assembly (54) comprising a stator core (102) including a set of circumferentially-spaced slots (106), and a set of windings (90, 120, 130, 150, 152, 154, 156, 158, 160) each including a first leg (122, 132) and a second leg (124, 134) with a dielectric coating (164, 166, 168, 170, 172, 174) applied onto at least a portion of the windings (90, 120, 130, 150, 152, 154, 156, 158, 160). The windings (90, 120, 130, 150, 152, 154, 156, 158, 160) are further received within at least a portion the set of the slots (106).