Multi-Phase Spool Power Transfer Circuit With Fault-Tolerant DC Linking

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Solution Overview

Problem

Aircraft electrical systems connecting rotary electric machines to gas turbine spools lack sufficient fault-tolerance, which is critical for safe operation, especially in the presence of multiple faults, as they are complex and prone to failures, posing risks to safe flight and operational reliability.

Innovation Solution

An electrical system comprising two rotary electric machines with identical phases, bidirectional converter circuits, and a switching arrangement that facilitates DC power transfer between gas turbine spools, ensuring fault-tolerant operation by connecting DC sides of converter circuits in both sets to maintain power transfer even in fault conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If electrical systems are used to connect rotary electric machines with gas turbine spools, then power transfer between spools is enabled and fuel consumption is reduced, but the system complexity increases and fault-tolerance requirements become more stringent

Engineering Contradiction:
Improvefuel consumptionVSAvoidsystem complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The electrical system is divided into multiple independent converter circuits, each handling a specific phase. Each converter circuit includes switching devices and control logic that can operate independently, allowing the system to segment power conversion tasks across multiple modular units rather than requiring a single complex converter.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system continuously monitors the operational status of each converter circuit and prepares backup pathways in advance. When a fault is detected in one converter circuit, the control system has already identified alternative routes for power transfer, enabling seamless switching without interrupting the overall power transfer function between spools.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If fault-tolerant design is implemented to ensure safe operation with single fault, then operational reliability is improved, but the device complexity and number of components increase

Engineering Contradiction:
Improveoperational reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple converter circuits are merged into a single integrated electrical system that shares common control logic and structural framework. The converter circuits share common mounting structures, control processors, and communication buses, reducing overall system complexity while maintaining the redundancy needed for fault tolerance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electrical system employs dynamic reconfiguration capabilities where the operational topology can change based on fault conditions. The control system dynamically switches between different operational modes: normal mode using all converter circuits, and degraded mode where faulty circuits are bypassed and power is transferred through alternative pathways, maintaining reliability without requiring static redundant components.

Inventive Principle:
Principle #15Dynamics

3Reliability

If redundant converter circuits are provided for fault tolerance, then the system can tolerate faults, but the quantity of components and system weight increase

Engineering Contradiction:
Improvefault-toleranceVSAvoidquantity of components
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

Each converter circuit is designed with universal functionality to handle multiple phases and operational scenarios. The converter circuits can operate in series or parallel configurations depending on system requirements, and each circuit is capable of handling the full power load independently if needed, reducing the need for dedicated backup components for each specific function.

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

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

The system provides reliable and fault-tolerant power transfer between gas turbine spools, enabling continued operation even with single faults, thus ensuring safe flight and reducing the risk of catastrophic events by maintaining power transfer and operational reliability.

Implementation Method 1

a first set of N bidirectional converter circuits for conversion of alternating current (ac) to and from direct current (dc)... a second set of N bidirectional converter circuits for conversion of ac to and from dc

Methodology Applied
Scientific EffectElectrical conversion (AC to DC):

Implementation Method 2

a switching arrangement having a number R of dc outputs for connection with the R-channel electrical network... wherein, for all n, the switching arrangement connects a dc side of the nth converter circuit in said first set is with a dc side of the nth converter circuit in said second set to facilitate dc power transfer

Methodology Applied
Scientific EffectElectrical power transfer: Conduction (electrical)

Data Source

PatentEP3796502B1Electrical systems
Publication Date: 2024.05.15 ROLLS ROYCE PLC
  • EP3796502B1 patent drawingFigure 1
  • EP3796502B1 patent drawingFigure 2
  • EP3796502B1 patent drawingFigure 3

AI summary

Electrical systems 201 for connecting rotary electric machines 111, 113 with gas turbine spools are provided. One such electrical system 201 comprises: a first rotary electric machine 111 mechanically coupled with a first gas turbine spool and a second rotary electric machine 113 mechanically coupled with a second gas turbine spool, each said electric machine 111, 113 having an identical even number N ≥ 4 of phases, each phase having a respective index n = (1,...,N), and each phase comprising an identical number P ≥ 1 of coils wound in a P-plex configuration in which adjacent phases are radially separated by 2π/NP mechanical radians; a first set 203 of N bidirectional converter circuits for conversion of alternating current (ac) to and from direct current (dc), each converter circuit having a respective index n and being connected with the P coils in the nth phase of the first rotary electric machine 111; and a second set 204 of N bidirectional converter circuits for conversion of ac to and from dc, each converter circuit having a respective index n and being connected with the P coils in the nth phase of the second rotary electric machine 113. For all n, a dc side of the nth converter circuit in said first set is connected with a dc side of the nth converter circuit in said second set to facilitate dc power transfer between the first gas turbine spool and the second gas turbine spool.