Gas Turbine Spool Motor-Generator for Multi-Voltage DC Power Transfer
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Solution Overview
Problem
Current gas turbine engines face challenges in efficiently transferring power between electrical networks operating at different voltages, which affects fuel efficiency and increases the risk of arcing and corona at altitude due to the need for medium voltage systems.
Innovation Solution
A gas turbine engine design that includes a first and second rotary electric machine mechanically coupled to the same spool, with connected power converters to interface with DC networks at different voltages, allowing the machines to operate as a motor-generator set for power transfer between the networks, and optionally includes a third electric machine for additional power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If medium voltage electrical systems are used to maintain acceptable current ratings, then current rating is improved, but the risk of arcing and corona at altitude increases
Solution Approach 1:
The electrical system is segmented into multiple voltage levels with dedicated DC networks operating at different voltages (e.g., 28V, 115V, 230V, or higher). Power converters interface between these networks, allowing current to be distributed across multiple voltage levels rather than using a single high-voltage system, thereby reducing arcing and corona risks while maintaining acceptable current ratings.
Solution Approach 2:
Power converters act as intermediary devices between DC networks operating at different voltages. These converters enable efficient power transfer between voltage levels without requiring direct high-voltage connections throughout the entire system, isolating high-voltage sections and reducing the overall risk of arcing and corona discharge.
2Use of energy by moving object
If power is transferred from low-pressure spool to high-pressure spool, then fuel efficiency is improved, but system complexity increases
Solution Approach 1:
The electrical machines are designed with multi-functionality, capable of operating in multiple modes (motor, generator, or idle) depending on the operational requirements. This allows the same hardware to enable power transfer between spools for fuel efficiency while also serving as starters or generators, thereby reducing overall system complexity despite the added functional capability.
Solution Approach 2:
The system dynamically adjusts the operational mode of electrical machines based on real-time conditions. Controllers monitor engine state and automatically switch between power generation, power consumption, and power transfer modes, enabling fuel efficiency improvements during certain phases while maintaining simplicity during others.
3Ease of operation
If electrical machines are coupled to high-pressure spool, then starting capability is improved, but fuel consumption increases
Solution Approach 1:
The starting function is segmented from the main power generation function. Electrical machines coupled to the low-pressure spool are dedicated primarily to starting and ground power functions, while high-pressure spool machines handle main power generation. This segmentation allows starting capability to be maintained without requiring high-pressure spool machines to operate in high-consumption starting modes during flight.
Solution Approach 2:
The low-pressure spool electrical machines serve themselves by generating their own operating power during flight conditions, reducing the need for high-pressure spool assistance. During starting operations, they work together in a coordinated manner where each machine contributes according to its optimal operating range, minimizing overall fuel consumption.
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 efficient power transfer between networks, reducing fuel consumption, minimizing voltage-related issues, and enhancing the engine's operational efficiency by allowing power to be supplied to accessories and energy storage devices, while also providing harmonic cancellation and resistance to electrostatic discharge.
Implementation Method 1
first and second rotary electric machines mechanically coupled to a spool of a gas turbine engine... operable as a motor-generator set for transfer of electrical power
Data Source
Figure 1
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AI summary
A gas turbine engine 101 having first and second rotary electric machines 111, 113 mechanically coupled with a spool is provided. The first rotary electric machine 111 is mechanically coupled with the spool and has connected therewith a first power converter 201 to interface the electric machine 111 with a first dc network 203 operating at a first voltage. The second rotary electric machine 113 is mechanically coupled with the spool and has connected therewith a second power converter 204 to interface the electric machine 113 with a second dc network 204 operating at a second voltage greater than said first voltage. The first electric machine 111 and the second electric machine 113 are operable as a motor-generator set for transfer of electrical power to the first dc network 203 from the second dc network 204.