Cryogenic MOSFET Gate Interface for Aircraft Power Control

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Solution Overview

Problem

Conventional power electronic systems in aircraft are inefficient due to a suboptimal weight/electrical power ratio, and standard control circuits are not suitable for cryogenic environments, where power components exhibit varying characteristics.

Innovation Solution

An electronic circuit with a power transistor operating at cryogenic temperatures and a control circuit at ambient temperatures, connected via an interfacing circuit, which includes measurement means to monitor and control the power transistor based on determined operating conditions, optimizing efficiency while using standard components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If power components are used in a cryogenic temperature environment to reduce resistance and Joule losses, then efficiency increases, but control circuit compatibility deteriorates

Engineering Contradiction:

ImproveJoule lossesVSAvoidcontrol circuit compatibility

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The control system is divided into two separate parts: a control circuit operating at ambient temperature and a power transistor operating at cryogenic temperature. This segmentation allows each component to operate in its optimal temperature range, resolving the contradiction between energy efficiency and control circuit compatibility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An interfacing circuit is introduced as an intermediary between the ambient temperature control circuit and the cryogenic temperature power transistor. This interfacing circuit handles the temperature transition and signal adaptation, enabling standard control circuits to control cryogenic power components without direct thermal contact

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If power transistor characteristics are allowed to vary significantly in cryogenic environment, then efficiency improves, but control precision deteriorates

Engineering Contradiction:

Improveenergy efficiencyVSAvoidcontrol precision

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

Measurement means are implemented to monitor the power transistor's operating parameters in the cryogenic environment. This feedback information is sent to the control circuit, which adjusts control signals accordingly. The feedback loop compensates for characteristic variations, maintaining control precision while allowing the power transistor to operate efficiently at cryogenic temperatures

Inventive Principle:

Principle #23Feedback

3Device complexity

If standard control circuits are used for cryogenic power components, then device complexity is reduced, but operational reliability deteriorates

Engineering Contradiction:

Improvecircuit complexityVSAvoidoperational reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The interfacing circuit serves as a buffer that isolates the standard control circuit from the harsh cryogenic environment. It translates control signals appropriately and handles the thermal transition, allowing standard components to be used while maintaining reliable control of the cryogenic power transistor

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of designing specialized cryogenic-compatible control circuits, the solution substitutes a standard ambient temperature control circuit combined with an interfacing circuit. This replacement achieves reliable control without the complexity of designing entirely new cryogenic control components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enhances the power transistor's efficiency under cryogenic conditions while maintaining controlled operation and reducing complexity and cost, improving the weight/electrical power ratio in aircraft systems.

Implementation Method 1

power components operating in a cryogenic environment have characteristics that may vary significantly from one to another or as a function of the environment

Methodology Applied

Scientific EffectCryogenic temperature operation: Cryogenics

Implementation Method 2

use the power components in a cryogenic temperature environment, which greatly reduces resistance and thus Joule losses

Methodology Applied

Scientific EffectJoule losses reduction: Joule Heating

Data Source

PatentEP4279889A1Improved power component for electric or hybrid aircraft

Publication Date: 2023.11.22 AIRBUS (SAS)

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AI summary

The invention relates to an electronic circuit (100) comprising a power transistor (110) of the MOSFET type comprising a gate (112) connected to a control circuit (140) of said gate (112), the electronic circuit (100) being configured with: - said control circuit (140) of said gate (112) being configured to operate at a temperature called ambient temperature, non-cryogenic, and, - said power transistor (110) as well as an interfacing circuit (130) connected between said gate (112) and said control circuit (140) being configured to operate at a cryogenic temperature, each of the components of said interfacing circuit (130) being established at a maximum distance (L) from the power transistor, the electronic circuit (100) further comprising at least one measurement signal (150b) connected between the interfacing circuit (130) operating at a cryogenic temperature and the control circuit (140) operating at ambient temperature, to make it possible to enslave the operation of the power transistor (110) with respect to a supervised operating parameter.