Electric Machine Assembly With Clutched Shaft Starting and Generation
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Solution Overview
Problem
Conventional gas turbine engines require complex and heavy starter systems, including transfer gearboxes and accessory gearboxes, which increase weight, complexity, and alter aerodynamics, and lack efficient integration for starting and generating electrical power.
Innovation Solution
An electric machine assembly that operates in both starting and generating modes, permanently coupled to a low speed shaft, selectively couples to a high speed shaft via a clutch assembly, eliminating the need for additional gearboxes and providing a direct rotational input for power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional starter systems with transfer gearboxes and accessory gearboxes are used, then the turbine engine can be started, but the weight and device complexity increase significantly
Solution Approach 1:
The patent combines the starter motor and generator into a single integrated electric machine assembly that is permanently coupled to the low-speed shaft. This merging eliminates the need for separate transfer gearboxes and accessory gearboxes, directly reducing device complexity while maintaining both starting and power generation functions.
Solution Approach 2:
The electric machine assembly serves multiple functions: it acts as a starter motor during engine startup by receiving electrical power to rotate the low-speed shaft, and later functions as a generator during operation by converting mechanical energy from the low-speed shaft into electrical power. This multi-functionality replaces multiple dedicated components with a single versatile unit.
2Reliability
If transfer gearboxes and accessory gearboxes are included in the starter system, then the turbine engine can be started, but the weight increases
Solution Approach 1:
The patent extracts and eliminates the transfer gearbox and accessory gearbox from the starter system by directly coupling the electric machine assembly to the low-speed shaft. This removal of unnecessary intermediate components significantly reduces the overall weight of the starting system while preserving the essential starting function.
3Reliability
If additional gearboxes are added to the starter system, then the turbine engine can be started, but the aerodynamics are altered and device complexity increases
Solution Approach 1:
The patent merges the starting function directly with the low-speed shaft rotation, eliminating the need for transfer gearboxes and accessory gearboxes. This consolidation simplifies the mechanical transmission path and reduces the number of moving parts, thereby reducing device complexity and minimizing aerodynamic interference.
4Productivity
If the electric machine is permanently coupled to the low speed shaft and selectively coupled to the high speed shaft, then power generation efficiency improves, but the clutch assembly complexity increases
Solution Approach 1:
The patent employs a clutch assembly that dynamically engages and disengages the connection between the electric machine assembly and the high-speed shaft based on operational requirements. During startup, the clutch engages to transmit motor power to the high-speed shaft; during power generation, the clutch disengages to allow the electric machine to freely convert low-speed shaft rotation into electrical power, optimizing productivity while managing complexity through controlled engagement.
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 solution simplifies the turbine engine design, reduces weight and complexity, improves stability, and allows for efficient power generation, while also reducing thermal effects during rapid shutdowns by maintaining low speed shaft rotation.
Implementation Method 1
an electrical machine connected via a permanent coupling mechanism to the low speed shaft and driven by the low speed shaft
Implementation Method 2
the electrical machine selectively operably coupled to the high speed shaft via a first clutch assembly
Data Source
AI summary
A turbine engine with a turbine core that includes a compressor section having a compressor coupled to a high speed shaft, a combustion section, a turbine section having a high pressure turbine coupled to the high speed shaft and a low pressure turbine coupled to a low speed shaft, and a nozzle section. The turbine engine also includes an electric machine that can operate in a first starting mode and a second generating mode.