Stator Winding Cooling via Interlocking Insulators

Solution Overview

Problem

Existing electric machines face inefficiencies in heat management due to indirect cooling methods, which can lead to reduced operational efficiency and potential coolant intrusion into the air gap, impeding machine operation.

Innovation Solution

The design incorporates interlocking insulators and end covers to create a coolant passage and barrier around the air gap, allowing for direct cooling of stator windings while preventing coolant intrusion, utilizing a liquid coolant system that circulates through the stator windings to efficiently remove heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If coolant is passed through passages formed in the stator core, then cooling of stator windings is achieved, but cooling efficiency is reduced due to indirect cooling

Engineering Contradiction:

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The stator core is segmented into multiple cooling passages formed between adjacent stator teeth, allowing coolant to flow through discrete channels that directly contact stator windings. This segmentation enables efficient heat removal from specific winding regions without requiring a monolithic cooling structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Coolant serves as an intermediary medium that transfers heat from stator windings to the cooling passages and then to the external cooling system. The coolant directly contacts the stator windings in the cooling passages, enabling direct cooling rather than indirect cooling through the stator core material.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If coolant flows over stator windings in the stator core, then direct cooling is achieved, but coolant may intrude into the air gap and impede machine operation

Engineering Contradiction:

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

An end cover extends over the stator windings to form a flexible barrier that contains the coolant within the cooling passages. This end cover acts as a shell that prevents coolant from escaping into the air gap while allowing the cooling system to maintain direct contact with the windings.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The harmful effect of coolant intrusion is extracted and eliminated by separating the cooling function from the air gap region. The cooling passages are confined to specific regions of the stator core, and the end cover extracts and contains the coolant, preventing it from entering the air gap where it would impede machine operation.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If indirect cooling is used through stator core passages, then coolant intrusion is prevented, but cooling efficiency is reduced

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The cooling passages are merged with the stator core structure, forming an integrated system where the passages are formed between adjacent stator teeth. This merging allows direct cooling of stator windings while maintaining the structural integrity of the stator core and preventing coolant intrusion into the air gap.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cooling passages serve as an intermediary structure that enables direct contact between coolant and stator windings while preventing coolant from reaching the air gap. The passages act as a controlled interface that provides efficient heat transfer without compromising the reliability of the air gap region.

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 solution enables direct cooling of stator windings, maintaining the air gap free of coolant and enhancing operational efficiency by effectively managing heat, thus improving the performance of electric machines.

Implementation Method 1

utilizing a liquid coolant system that circulates through the stator windings to efficiently remove heat

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS11469647B2Oil cooling system for a stator of an electric machine

Publication Date: 2022.10.11

AI summary

An electric machine including a rotor and a stator positioned about the rotor. The stator includes a stator core having a plurality of stator teeth and a plurality of stator windings supported by the stator core about the plurality of stator teeth. The plurality of stator windings include a first end turn and a second end turn. The stator includes a plurality of interlocking insulators extending about corresponding ones of the plurality of stator teeth. Each of the plurality of interlocking insulators includes a first base portion extending circumferentially outwardly in a first direction and a second base portion extending circumferentially outwardly in a second direction. The first base portion being configured to inter-engage with a second base portion on an adjacent interlocking insulator to form a coolant passage and a coolant barrier about the air gap.