Silicon Carbide Switch Bus Bar Thermal Management

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Solution Overview

Problem

Solid state switches, particularly silicon and germanium-based ones, face limitations in high-temperature operations and generate thermal energy, necessitating bulky cooling structures and increased weight, which is undesirable in aerospace applications where size and weight impact performance.

Innovation Solution

A silicon carbide-based switch mounting arrangement using directly mounted bus bars with insulating material to facilitate thermal energy communication, where bond wires connect switches across bus bars for efficient thermal and electrical communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional silicon or germanium solid state switches are used, then the switching function is achieved, but the unit requires substantial cooling structures increasing weight and size

Engineering Contradiction:

Improveswitching functionVSAvoidunit weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent changes the material parameter of the solid state switch from traditional silicon or germanium to silicon carbide, which has superior thermal conductivity and can operate at higher temperatures. This material substitution eliminates the need for substantial cooling structures, thereby reducing unit weight while maintaining reliable switching function.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs silicon carbide, a composite material with superior thermal and electrical properties compared to traditional semiconductors. This composite material enables the switch to handle higher thermal loads without requiring additional cooling infrastructure, thus reducing overall unit weight.

Inventive Principle:

Principle #40Composite materials

2Reliability

If traditional silicon or germanium solid state switches are used, then the switching function is achieved, but the unit requires substantial cooling structures increasing size

Engineering Contradiction:

Improveswitching functionVSAvoidunit size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

By changing the material parameter to silicon carbide with higher temperature operation capability, the cooling structure size is dramatically reduced, thereby reducing the overall unit area while maintaining switching reliability.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If interconnects are incorporated to move thermal energy away from switches, then thermal management is improved, but added weight and packaging requirements increase

Engineering Contradiction:

Improvethermal energy managementVSAvoidunit weight

Core Design Contradiction:

TemperatureVSWeight of stationary object

Solution Approach 1:

The patent extracts and eliminates the need for separate thermal management interconnects by integrating the thermal conduction function directly into the silicon carbide switch material itself, which has inherent superior thermal conductivity, thereby reducing added weight.

Inventive Principle:

Principle #2Taking out (Extraction)

4Temperature

If interconnects are incorporated to move thermal energy away from switches, then thermal management is improved, but increased inductance and capacitance occur

Engineering Contradiction:

Improvethermal energy managementVSAvoidelectrical properties

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the electrical connection and thermal management functions into a single integrated structure. The silicon carbide switch directly contacts the substrate, simultaneously providing both electrical connectivity and thermal conduction pathways, thereby eliminating separate interconnects that would add inductance and capacitance.

Inventive Principle:

Principle #5Merging (Combining)

5Reliability

If traditional solid state switches are used, then switching function is achieved, but excessive size impacts aerospace performance

Engineering Contradiction:

Improveswitching functionVSAvoidunit size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

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 arrangement allows silicon carbide switches to operate at higher temperatures with reduced size and weight, effectively managing thermal energy and improving performance in space and aerospace applications.

Implementation Method 1

the first bus bar is configured to communicate thermal energy away from the first switch

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

bond wires electrically connecting the first switch and the second switch to each other

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2254152B1Solid state switch arrangement and method of arranging a switch

Publication Date: 2020.02.26 HAMILTON SUNDSTRAND CORP

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AI summary

An example solid state switching arrangement includes at least one bus bar (18a, b) configured to carry electrical current and at least one switch (14) that is silicon carbide based. The switch is secured relative to the bus bar and the bus bar is configured to communicate thermal energy away from the switch. An example method of arranging a switch includes mounting a silicon carbide based switch (14) relative to a bus bar (18a, b) and communication thermal energy away from the silicon carbide based switch using the bus bar.