Multi-Shaft Power Transfer With Integrated Planetary Electrical Machines

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Solution Overview

Problem

Existing electrical power-transfer systems in gas turbine engines are bulky and heavy, reducing efficiency due to the need for components that operate efficiently across a wide range of shaft speeds.

Innovation Solution

A planetary gear system with integrated electrical machines, including a first electrical machine connected to a ring gear to generate power, a second electrical machine to drive a sun gear, and a third electrical machine to drive a second engine shaft, with a controller regulating the sun gear speed to maintain efficient power transfer across varying engine conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If electrical power-transfer systems use bulky components to operate efficiently across a wide range of shaft speeds, then efficiency is improved, but weight increases and space is occupied

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidsystem weight

Core Design Contradiction:

Loss of energyVSWeight of moving object

Solution Approach 1:

The patent integrates multiple electrical machines (generators and motors) within the planetary gear system structure, nesting them together to share common mounting space and reduce overall system volume. This allows the system to maintain multiple efficient operating points across different shaft speeds while reducing the bulky components issue.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The electrical machines are designed to perform multiple functions - serving as both generators and motors depending on operating conditions, and enabling power transfer in multiple directions between shafts. This multi-functionality reduces the need for separate dedicated components, thereby reducing weight while maintaining efficiency across a wide speed range.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Loss of energy

If electrical power-transfer systems use bulky components to operate efficiently across a wide range of shaft speeds, then efficiency is improved, but volume occupied increases

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidsystem volume

Core Design Contradiction:

Loss of energyVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent combines the power transfer function with electrical machine integration, merging what would traditionally be separate systems into a unified compact assembly. This reduces the total volume occupied while maintaining the ability to operate efficiently across a wide range of shaft speeds.

Inventive Principle:

Principle #5Merging (Combining)

3Loss of energy

If power is transferred between spools to influence rotational speeds, then engine efficiency is improved, but system complexity increases

Engineering Contradiction:

Improveengine efficiencyVSAvoidpower transfer system complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The planetary gear system serves as a mechanical intermediary that couples the electrical machines to the engine shafts, providing a structured interface for power transfer. This intermediary structure organizes the complexity into manageable components while enabling efficient power transfer between spools to optimize engine performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 achieves efficient power transfer across a wide range of engine speeds, reducing weight and increasing power density while maintaining engine efficiency.

Implementation Method 1

a first electrical machine connected to be driven by the ring gear to generate electrical power

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a second electrical machine connected to drive the sun gear

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

a third electrical machine configured to receive electrical power generated by the first electrical machine and operable as a motor to drive a second engine shaft

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP4628716A1Multi shaft power transfer system

Publication Date: 2025.10.08 HAMILTON SUNDSTRAND CORP

Figure 1
Figure 2
Figure 3A~3B

AI summary

There is provided an electrical power-transfer system (2) for an engine (4) having first and second engine shafts (6, 8), and a method of operating such a system. The system has a planetary gear system (10) comprising a sun gear (18), a ring gear (22), a plurality of planetary gears (20) enmeshed with the sun gear (18) and the ring gear (22), and a carrier (24) supporting the plurality of planetary gears (20), wherein the carrier (24) is configured for connection to be driven by a first engine shaft (6). The system has a first electrical machine (12) connected to be driven by the ring gear (22) to generate electrical power, a second electrical machine (14) connected to drive the sun gear (18), and a third electrical machine (16) configured to receive electrical power generated by the first electrical machine (12) and operable as a motor to drive a second engine shaft (8).