Integrated Power Electronics Layout for Compact Polyphase Machines

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Solution Overview

Problem

Existing solutions for integrating power electronics with polyphase electric machines in aircraft and rotorcraft face challenges in compactness, thermal management, and compatibility, particularly due to radial surface integration issues and axial integration constraints.

Innovation Solution

A hybrid architecture is proposed where power electronics are both internal and external to the casing, with n power electronic modules distributed along the casing's internal circumference and a single annular DC bus capacitor, utilizing a cooling circuit with U-shaped tubes to enhance cooling and temperature resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If power electronics are integrated internally in the housing, then compactness is improved, but thermal constraints and volume of DC bus capacitors worsen

Engineering Contradiction:
ImprovecompactnessVSAvoidthermal constraints
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The power electronics are segmented into multiple modules distributed along the internal circumference of the housing extension, allowing thermal management to be distributed as well. The cooling circuit is segmented into multiple U-shaped tubes that can be strategically positioned to cool different modules, resolving the thermal constraints while maintaining compact integration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extends the housing in the longitudinal dimension to create space for power electronics modules and DC bus capacitors, moving them from a confined radial space to a distributed longitudinal arrangement. This dimensional change allows better thermal access while maintaining overall compactness.

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

2Power

If a large volume DC bus capacitor is used, then electrical performance is improved, but system volume and weight increase

Engineering Contradiction:
Improveelectrical performanceVSAvoidsystem volume
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The DC bus capacitors are nested within the housing extension, utilizing the extended longitudinal space rather than occupying additional external volume. The capacitors are positioned in the annular space between the housing wall and the power electronics modules, effectively nesting them within the existing structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of using large radial capacitors that would increase volume, the patent distributes multiple smaller capacitors along the longitudinal extension, changing from a single large component to multiple distributed components in the longitudinal dimension.

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

3Ease of manufacture

If power electronics are radially integrated on the housing surface, then integration is simplified, but compactness and semiconductor device distribution worsen

Engineering Contradiction:
Improveintegration simplicityVSAvoidcompactness
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The power electronics are segmented into multiple modules distributed along the internal circumference of the housing extension, improving both compactness and thermal management while maintaining integration simplicity through modular construction.

Inventive Principle:
Principle #1Segmentation

4Volume of moving object

If axial surface integration is used, then space requirements are reduced, but availability of end space worsens

Engineering Contradiction:
Improvespace utilizationVSAvoidend space availability
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent integrates power electronics along the internal circumference of a longitudinal extension rather than at the ends, utilizing the lateral surface area of the extended housing. This changes the integration from end-space-dependent to surface-area-dependent, improving adaptability while maintaining space efficiency.

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

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 significantly increases power density, improves heat extraction, and enhances temperature resistance, addressing the limitations of previous integration methods while minimizing volume and weight.

Implementation Method 1

a cooling circuit with U-shaped tubes to enhance cooling and temperature resistance

Methodology Applied
Scientific EffectHeat extraction: Heat Exchanger

Implementation Method 2

a cooling fluid is introduced at a first end of said U-shaped tubes through a radial inlet orifice disposed at a free end of said longitudinal casing extension and extracted at a second end of said U-shaped tubes

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3830934B1Polyphase electrical machine with integrated power electronics and an integrated coolant circuit
Publication Date: 2025.01.01 SAFRAN SA
  • EP3830934B1 patent drawingFigure 1
  • EP3830934B1 patent drawingFigure 2~5
  • EP3830934B1 patent drawingFigure 3

AI summary

The invention relates to a polyphased electrical machine with n phases, n>3, comprising a housing (24) defining a longitudinal axis, a stator (26), and a rotor (28) comprising a mechanical drive shaft (30), the electrical machine being provided with power electronics (32) and a coolant circuit, said power electronics (32) being formed from n power electronics modules (32A1-32A6) which are regularly distributed over an inner circumference of a longitudinal extension (24A) of said housing, an outer circumference of which is covered by a single annular DC bus decoupling capacitor (16) which is electrically connected to said n power electronics modules (32A1-32A6), said coolant circuit comprising a plurality of U-shaped tubes with a tubular outgoing part (38A) extending over an entire length of the housing (24), including said longitudinal extension (24A) of the housing, and a shorter tubular return part (38B) extending over a length of the housing (24), excluding said longitudinal extension (24A) of the housing .