Modular Rail Power Module Cooling for Easier IGBT Maintenance

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Solution Overview

Problem

Current traction boxes on railway vehicles require frequent maintenance and replacement of semiconductor elements, which are heavy and require multiple operators due to their weight, and cooling systems using fluid-based thermal interfaces complicate disassembly and maintenance.

Innovation Solution

The traction box features a lightweight electric current conversion device with insulated gate bipolar transistors and a solid thermal interface for efficient heat transfer, along with a closed heat transfer fluid circuit and a second heat exchanger that utilizes air flow for cooling, allowing for easy maintenance by a single operator without the need for fluid-based interfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If semiconductor elements and cooling systems are integrated in conventional power modules, then cooling efficiency is improved, but maintenance complexity and operator requirements increase due to heavy weight and fluid-based thermal interfaces

Engineering Contradiction:
Improvecooling efficiencyVSAvoidmaintenance complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The power module is divided into modular conversion units, each with its own support structure that can be independently removed. This segmentation allows maintenance of individual units without dismantling the entire cooling system, reducing maintenance complexity while preserving cooling efficiency through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The semiconductor elements are extracted from their conventional fixed mounting and placed on removable supports that can be easily detached from the conversion units. This extraction enables simple removal of semiconductor elements for maintenance without affecting the cooling system integration, thereby reducing maintenance complexity while maintaining cooling performance.

Inventive Principle:
Principle #2Taking out (Extraction)

2Temperature

If fluid-based thermal interfaces are used for cooling semiconductor elements, then heat transfer efficiency is improved, but disassembly and maintenance become more complex

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoiddisassembly ease
Core Design Contradiction:
TemperatureVSEase of repair

Solution Approach 1:

The fluid-based thermal interface is extracted from the maintenance process by pre-applying it to the support structure before mounting the semiconductor elements. This extraction allows the thermal interface to remain effective for heat transfer while eliminating the need to handle fluids during disassembly and maintenance, thereby improving ease of repair while maintaining heat transfer efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The thermal interface material is applied in advance to the support structure before the semiconductor elements are mounted. This preliminary action ensures optimal thermal contact is established before assembly, maintaining heat transfer efficiency while eliminating the need to manipulate thermal interfaces during maintenance operations, thus improving ease of repair.

Inventive Principle:
Principle #10Preliminary action

3Power

If conversion units are designed with high power capacity, then electrical performance is improved, but weight increases requiring multiple operators for maintenance

Engineering Contradiction:
Improveelectrical performanceVSAvoidcomponent weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The power module is segmented into multiple conversion units, each with optimized power capacity. This segmentation distributes the total power capacity across lighter individual units, maintaining overall electrical performance while reducing the weight of each maintenanceable component to levels that can be handled by single operators.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conversion units are designed with dynamic removability through removable supports, allowing lightweight individual units to be easily installed and removed. This dynamic design maintains high power capacity through modular aggregation of units while ensuring each unit remains lightweight enough for single-operator maintenance.

Inventive Principle:
Principle #15Dynamics

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 configuration simplifies maintenance by reducing the weight of components and eliminating the need for fluid-based thermal interfaces, enabling quick and efficient replacement of semiconductor elements and reducing maintenance constraints.

Implementation Method 1

said thermal interface ensures a heat transfer between the plurality of semiconductor elements of said conversion unit and said first heat exchanger

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a closed circuit of heat transfer fluid; and a second heat exchanger capable of transferring heat from said heat transfer fluid to an air flow

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

a second heat exchanger capable of transferring heat from said heat transfer fluid to an air flow generated by movement of the railway vehicle

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP4028272B1Electric power module
Publication Date: 2024.11.13 ALSTOM HOLDINGS SA
  • EP4028272B1 patent drawingFigure 1
  • EP4028272B1 patent drawingFigure 2

AI summary

The present invention relates to an electric power module (12) for a rail vehicle (10), comprising an electric current conversion device (20) and a device (22) for cooling said conversion device; said conversion device comprising a plurality of conversion units (24), each conversion unit comprising a plurality of semiconductor elements (28); said cooling device comprising a plurality of heat exchangers (30) such that, in an assembled position, the plurality of semiconductor elements (28) is in thermal contact with said exchanger; the module comprising means for removably assembling each conversion unit together with the corresponding exchanger, said support being capable of being separated from said exchanger and from the rest of the electric power module.