Stator Cooling Channels for High-Density Motor Windings

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Solution Overview

Problem

Traditional cooling methods for high-density electric motors, such as external fins and liquid cooling jackets, often leave hot spots in the stator windings due to inadequate cooling at the axial centerline, failing to effectively manage thermal issues in compact motor designs.

Innovation Solution

A stator design with a stator hub, teeth, and windings that form a coolant channel between the stator slot base and the inner winding portion, utilizing insulating separators with cooling passages and fins to enhance thermal conductivity and coolant flow, connected to inlet and outlet headers for efficient fluid circulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional external fins or liquid cooling jackets are used, then the motor structure is simple and easy to manufacture, but cooling effectiveness is insufficient and hot spots occur at the axial centerline

Engineering Contradiction:

Improvecooling effectivenessVSAvoidcooling channel structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The cooling system is segmented into multiple independent cooling channels formed between individual windings and the stator slot base. Each cooling channel operates independently to remove heat from specific winding regions, allowing targeted cooling where needed rather than using a single complex cooling structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cooling channels are nested within the existing stator structure by utilizing the space between the windings and stator slot base. The cooling passages are formed within the stator teeth and slot base, nesting the cooling function inside the structural components rather than adding external cooling elements.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Temperature

If cooling channels are formed between windings and stator slot base, then cooling effectiveness improves, but manufacturing complexity increases

Engineering Contradiction:

Improveheat dissipationVSAvoidstator assembly

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The cooling channels are formed during the winding insertion process itself. The windings are positioned and secured to the stator slot base in advance, creating the cooling channels as part of the assembly process rather than requiring separate channel formation steps after assembly.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The winding structure itself serves dual purposes: it provides both the electrical function and creates the cooling channels. The positioning and securing of windings to the stator slot base automatically forms the cooling passages, allowing the assembly process to create the cooling function without additional manufacturing steps.

Inventive Principle:

Principle #25Self-service

3Power

If high-power-density windings are used, then motor power output increases, but heat generation increases requiring more complex cooling

Engineering Contradiction:

Improvepower densityVSAvoidthermal management

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

Different regions of the stator receive different cooling intensities based on their thermal requirements. The cooling channels are distributed throughout the stator structure, allowing localized cooling adjustment where high power density windings generate more heat, while maintaining simplicity in lower heat generation areas.

Inventive Principle:

Principle #3Local quality

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 design effectively dissipates heat generated by the windings into the coolant, improving thermal management and reducing weight by balancing cooling capacity with weight constraints, particularly beneficial for high-power-density applications like aviation-class electric motors.

Implementation Method 1

fluid can be passed between the stator slot base and the inner winding portion to cool the inner winding portion

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

This design effectively dissipates heat generated by the windings into the coolant, improving thermal management

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS11757335B2Cooling channels in a high-density motor

Publication Date: 2023.09.12 HAMILTON SUNDSTRAND CORP

AI summary

A stator includes a stator hub and a plurality of stator teeth extending from the stator hub that define a stator slot having a stator slot base. At least one winding is disposed in the stator slot and the stator also includes a back iron. The winding surrounds the back iron and is held apart from the stator slot base so that a fluid channel is defined between an inner winding portion of the at least one winding so fluid can be passed between the stator slot base and the inner winding portion to cool the inner winding portion.