Fault-Tolerant Electric Drive Segmentation for Aircraft Fuel Pumps

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Solution Overview

Problem

Conventional electric drive systems for aircraft fuel pumps are prone to significant performance loss and potential engine flameout due to electrical failures, as they lack adequate redundancy and fault tolerance, leading to rapid fuel flow reduction and increased system weight and complexity.

Innovation Solution

A fault-tolerant electric drive system with at least four independent electric drive phases, powered by a multiphase alternator and motor controller, utilizing a common multiplexed serial bus and power bridges with AC-DC links and inverters, allowing seamless operation even after loss of a single phase, with each phase being self-sufficient and isolated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electric drive systems are used for aircraft fuel pumps, then the system structure is simple, but the system lacks fault tolerance and results in significant performance loss or engine flameout upon electrical failure

Engineering Contradiction:
Improvefault toleranceVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electric drive system is segmented into multiple independent phases (at least four phases). Each phase includes its own power bridge, phase controller, and motor windings, allowing the system to operate with any single phase failed. This segmentation provides inherent fault tolerance without requiring complex external redundancy systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system combines multiple drive phases and power bridges into a single integrated motor controller unit. The common DC power supply, control bus, and housing merge these components into one compact assembly, reducing overall system complexity while maintaining the benefits of multiple independent phases.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If fully redundant systems are implemented to ensure continuous fuel supply, then reliability improves, but system weight and complexity increase significantly

Engineering Contradiction:
Improvefuel supply continuityVSAvoidsystem weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

Instead of implementing separate redundant pump systems, the invention segments the electrical drive into multiple phases within a single pump system. This allows fault tolerance without duplicating the entire pump assembly, significantly reducing weight compared to mechanical redundancy approaches.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The common DC power supply acts as an intermediary that feeds all phase controllers, eliminating the need for separate power supplies for each redundant system. This single power source supports multiple phases, reducing overall system weight while maintaining reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If additional protection and isolation components are added to prevent short circuits in redundant systems, then system safety improves, but device complexity and size increase rapidly

Engineering Contradiction:
Improveelectrical protectionVSAvoidprotection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each phase is electrically isolated with its own power bridge and current monitoring, creating natural protection barriers. The segmented architecture prevents short circuits from propagating across phases without requiring additional complex isolation components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Current monitoring loops in each power bridge provide real-time feedback to detect abnormal conditions. This feedback mechanism enables proactive fault detection and protection without requiring complex external protection circuits.

Inventive Principle:
Principle #23Feedback

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

Enables continuous operation with minimal performance loss in case of single-phase failure, reducing the risk of engine flameout and system complexity, while eliminating the need for external power sources and bulky filtering components.

Implementation Method 1

an alternator arranged to supply electrical power via the motor controller to the electric motor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an electric motor mechanically coupled to the main fuel pump

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP2617998B1Fault tolerant electric drive system
Publication Date: 2019.07.03 ROLLS ROYCE PLC
  • EP2617998B1 patent drawingFigure 1
  • EP2617998B1 patent drawingFigure 2
  • EP2617998B1 patent drawingFigure 3

AI summary

A fault tolerant electric drive system comprises an alternator (10), a motor controller (12) and an electric motor (14), wherein the alternator (10) and motor (14) each have a plurality of corresponding independent phase windings, the motor controller (12) having a plurality of independent phase drives (16) corresponding to the phase windings, and a plurality of independent electric drive phases is defined by connecting each corresponding phase winding of the alternator (10) and motor (14) to a corresponding phase drive (16) of the motor controller (12).