AMB Substrate Power Module Thermal Dissipation

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Solution Overview

Problem

Existing electrical power modules for aeronautical applications face challenges in achieving high reliability, compactness, and reduced mass due to issues with heat dissipation and mechanical stress from differential expansions, which can lead to solder cracking and reliability failures.

Innovation Solution

The module integrates power transistors on a single AMB/Si3N4 substrate acting as a thermal dissipation sole, with control components on a ceramic substrate, and features flexible power connection pads and a laminated copper-kapton power bus to enhance thermal conductivity and mechanical flexibility, eliminating the need for additional heat dissipation bases and reducing component count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If power transistors are mounted on separate power substrates with additional copper base for heat dissipation, then thermal dissipation is improved, but device complexity and mass increase

Engineering Contradiction:
Improveheat dissipationVSAvoidmodule structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the substrate and heat dissipation base into a single integrated AMB/Si3N4 substrate. The substrate simultaneously serves as the mounting platform for power transistors and as the thermal dissipation path, eliminating the need for separate copper base plates and reducing structural complexity while maintaining effective heat removal from power devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The AMB/Si3N4 substrate performs multiple functions: it provides mechanical support for power transistors, conducts heat away from the devices, and serves as the foundational structure for the entire module. This multi-functional design reduces the number of components needed while achieving both structural and thermal management objectives.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If additional copper base and separate substrates are used for heat dissipation, then thermal management is improved, but mass and volume increase

Engineering Contradiction:
Improvethermal dissipationVSAvoidmodule mass
Core Design Contradiction:
TemperatureVSWeight of stationary object

Solution Approach 1:

The patent combines the heat dissipation function with the substrate structure itself, eliminating redundant copper base plates and separate heat sinks. The AMB/Si3N4 substrate's inherent thermal conductivity is sufficient for heat dissipation, reducing material usage and overall module mass while maintaining effective thermal management.

Inventive Principle:
Principle #5Merging (Combining)

3Length of stationary object

If control substrate is spaced away from power assembly, then connection lengths are reduced, but device complexity increases

Engineering Contradiction:
Improveconnection lengthVSAvoidsubstrate arrangement
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent integrates the control substrate directly onto the AMB/Si3N4 substrate, eliminating the need for spacing and complex inter-substrate connections. Power and control components are mounted on the same substrate plane, minimizing connection lengths while simplifying the overall structural arrangement through unified mounting.

Inventive Principle:
Principle #5Merging (Combining)

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 increases reliability, reduces mass and size, and improves functional behavior by directly integrating heat dissipation and control components, while the flexible connection pads and Faraday cage design mitigate mechanical stress and electromagnetic interference.

Implementation Method 1

a main substrate of the AMB/Si3N4 type carrying the power transistors, this main substrate constituting in itself a thermal dissipation base for the heat generated by the power transistors by being arranged in the module to be in direct contact with a carrier structure ensuring cooling by conduction

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

each consisting of a conductive sheet cut and folded around a central region to enclose a clamping nut arranged under the central region of the sheet including a central orifice, each pad being fixed to the main substrate by welding one or more ends of the folded sheet constituting it to a track of this substrate, each nut being arranged to receive a screw for fixing a power supply element to the pad; the sheet metal having initial tabs folded in the same direction so as to define, with the rest of the sheet metal, a cage immobilizing the nut

Methodology Applied
Scientific EffectGeometric constraint: Geometry

Data Source

PatentEP2850658B1Electric power module arrangement
Publication Date: 2022.11.30 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP2850658B1 patent drawingFigure 1~3
  • EP2850658B1 patent drawingFigure 4~6
  • EP2850658B1 patent drawingFigure 7~9

AI summary

The invention relates to an electronic power module (14) comprising power transistors (15) in addition to control components (17) for controlling said power transistors (15), said module (14) being cooled especially by heat conduction. The module according to the invention comprises: a main AMB/Si3N4-type substrate (16) carrying the power transistors (15), said main substrate (16) forming per se a heat dissipation base for the dissipation of the heat generated by the power transistors (15) by being arranged in the module (14) in such a way as to be directly in contact with a carrier structure (21) providing conductive cooling when the module is assembled; and a ceramic substrate (18) carrying the control components (17), said ceramic substrate (18) being carried itself by the main substrate (16).