Hybrid Propeller Gearbox With Planetary Electric Machine Coupling
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Solution Overview
Problem
The integration of an electric machine with a gas turbine engine is not consistently effective across all operation modes, necessitating improved assemblies for enhanced performance.
Innovation Solution
A gearbox assembly incorporating a planetary gear set with a sun gear, planet gear, and ring gear, along with an electric machine assembly that includes a rotor and stator, is designed for connection to the engine's drive shafts, allowing for efficient power transmission and operation in various modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an electric machine is coupled to the engine shaft, then hybrid functions are added to the gas turbine engine, but the electric machine may not operate as desired across all operation modes
Solution Approach 1:
The patent applies dynamics by making the electric machine's rotational speed independent of the engine shaft's rotational speed through the decoupling mechanism. The electric machine can rotate at variable speeds determined by electrical power frequency rather than being constrained to match engine shaft speed, enabling reliable operation across all engine operation modes including shutdown, idle, and various power levels.
Solution Approach 2:
The patent uses a decoupling mechanism as an intermediary between the engine shaft and the electric machine. This intermediary includes a first decoupling mechanism with a first gear set and a second decoupling mechanism with a second gear set, allowing the electric machine to be mechanically connected to the engine shaft while operating at independent speeds, thus resolving the contradiction between adaptability and reliability.
2Power
If the electric machine is mechanically connected to the engine shaft, then power can be added or extracted, but the electric machine speed must match engine shaft speed
Solution Approach 1:
The patent replaces the direct mechanical speed coupling system with an electrical system. Instead of requiring mechanical synchronization between engine shaft and electric machine speeds, the invention uses electrical power frequency to determine electric machine rotational speed. This substitution allows power addition or extraction while eliminating the speed matching constraint through the use of electrical rather than purely mechanical control.
3Adaptability or versatility
If the electric machine operates at variable speeds, then it can function across all operation modes, but it requires a decoupling mechanism from the engine shaft
Solution Approach 1:
The patent applies segmentation by dividing the coupling system into separate functional segments: the engine shaft connection segment and the electric machine connection segment. The first decoupling mechanism segments the connection to allow independent rotation of the electric machine from the engine shaft, while the second decoupling mechanism provides additional decoupling capability. This segmentation enables variable speed operation while managing the complexity through modular functional separation.
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 enables improved power extraction and addition to the gas turbine engine, facilitating efficient operation across different modes and reducing the likelihood of engine damage during shutdown.
Implementation Method 1
a planetary gear set comprising a sun gear, a planet gear, and a ring gear, the sun gear configured for connection to a first drive shaft of the gas turbine engine and the ring gear configured for connection to a second drive shaft of the gas turbine engine
Implementation Method 2
an electric machine assembly comprising an input and an electric machine, the electric machine comprising a rotor coupled to the input and a stator fixedly positioned within the gearbox assembly
Implementation Method 3
In certain operations, the electric machine may be operated in a generator mode whereby the electric machine produces electric energy to be stored in battery
Data Source
AI summary
A gearbox assembly for a gas turbine engine includes a planetary gear set comprising a sun gear, a planet gear, and a ring gear, the sun gear configured for connection to a first drive shaft of the gas turbine engine and the ring gear configured for connection to a second drive shaft of the gas turbine engine, and an electric machine assembly comprising an input and an electric machine. The electric machine comprising a rotor coupled to the input and a stator fixedly positioned within the gearbox assembly, the input of the electric machine assembly coupled to one of the sun gear, the ring gear, or the planet gear of the planetary gear set.