Helicoidal Cooling Guide for Core-Coil Gap Heat Removal

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Solution Overview

Problem

Medium frequency transformers face challenges in efficient cooling due to their compact size, which leads to hot spots at the low-voltage coil and core, limiting power density and increasing costs.

Innovation Solution

A helicoidal guide is placed within the spatial gap between the core and the first coil to direct a coolant flow, optimizing air flow and heat transfer by circumventing the core yokes, thereby enhancing cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If the transformer size is reduced to achieve medium frequency operation, then weight and cost are reduced, but cooling efficiency deteriorates due to compact size and hot spots

Engineering Contradiction:
Improvetransformer weightVSAvoidcooling efficiency
Core Design Contradiction:
Weight of stationary objectVSTemperature

Solution Approach 1:

The cooling system is segmented into multiple independent channels: a first cooling channel for the low-voltage coil and a second cooling channel for the high-voltage coil. The helicoidal guide further segments the first cooling channel into multiple flow paths that wrap around the core, distributing coolant flow to prevent hot spots in the compact transformer structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The helicoidal guide introduces a three-dimensional spiral flow path within the limited spatial gap between the low-voltage coil and core. This transforms the coolant flow from a simple linear or radial path into a multi-turn helical path, increasing the effective cooling surface area and coolant-coil contact time without increasing the transformer's external dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If the low-voltage coil is positioned close to the core to reduce size, then power density increases, but cooling becomes more difficult due to limited spatial gap

Engineering Contradiction:
Improvepower densityVSAvoidcooling structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The helicoidal guide is nested within the spatial gap between the low-voltage coil and the core, utilizing the existing limited space. The guide's helical structure is contained within this annular region, creating multiple cooling passes without requiring additional external space or increasing the transformer's overall footprint.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The helicoidal guide employs a curved spiral geometry that conforms to the cylindrical spatial gap between the coil and core. This curved path maximizes the use of available space, creating an efficient cooling flow pattern that follows the natural geometry of the transformer's internal structure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Device complexity

If conventional cooling methods are used in compact MFT, then device simplicity is maintained, but hot spots develop at the low-voltage coil and core

Engineering Contradiction:
Improvecooling system simplicityVSAvoidhot spot temperature
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The helicoidal guide acts as an intermediary component that directs and optimizes coolant flow between the coolant source and the heat-generating components (low-voltage coil and core). This simple geometric feature transforms conventional cooling into targeted cooling by guiding the coolant through a spiral path that ensures uniform heat removal across the coil and core surfaces.

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 improves temperature distribution, increases power density, and reduces costs by ensuring effective cooling of medium frequency transformers and inductors.

Implementation Method 1

the helicoidal guide being placeable within the spatial gap and configured to guide a flow of coolant through the spatial gap

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

the coolant is in direct contact with the first coil and optionally with the core

Methodology Applied
Scientific EffectThermal Conduction: Conduction (thermal)

Implementation Method 3

guide a flow of coolant through the spatial gap, wherein the coolant is in direct contact with the first coil

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4099346B1Helicoidal guide for the cooling of a medium-frequency transformer
Publication Date: 2024.08.21 ABB (SCHWEIZ) AG
  • EP4099346B1 patent drawingFigure 1
  • EP4099346B1 patent drawingFigure 2
  • EP4099346B1 patent drawingFigure 3

AI summary

A helicoidal guide (140) configured and shaped for cooling an inductor and/or a transformer (100) with a core (120) and a first coil (110) having a spatial gap (130) between the core (120) and the first coil (110), the helicoidal guide (140) being placeable within the spatial gap (130) and configured to guide a flow of coolant through the spatial gap (130), wherein the coolant is in direct contact with the core (120) and/or the first coil (110).