Gas Turbine Starter Control Across Torque, Acceleration, And Speed
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Solution Overview
Problem
Gas turbine engines face challenges in efficiently managing the transition from startup to light-off, particularly in controlling the torque and speed of the spool to ensure consistent and reliable engine operation.
Innovation Solution
A starter assembly with a controller that modulates an electric motor in multiple control modes, including torque, acceleration, and speed control, to manage the spool's rotation and ensure it reaches target conditions before and after light-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the starter provides maximum torque during engine start-up, then the spool can be accelerated reliably, but the transition to light-off becomes difficult to control precisely
Solution Approach 1:
The control system dynamically transitions between torque control mode and acceleration control mode based on real-time engine operating conditions. This allows the starter to provide maximum torque when needed for reliable start-up while seamlessly transitioning to precise acceleration control as the engine approaches light-off, resolving the contradiction between reliability and control precision.
Solution Approach 2:
The system changes the control parameter from torque to acceleration as the engine progresses through the start-up sequence. This parameter transition enables the starter to deliver high torque initially while maintaining precise control capability during the critical transition to light-off, addressing both reliability and ease of operation requirements.
2Device complexity
If the controller uses a single control mode throughout startup, then the control system remains simple, but it cannot optimize performance across different operating phases
Solution Approach 1:
The startup process is segmented into distinct phases, each governed by a specific control mode. The controller divides the startup sequence into torque control phase (for initial acceleration) and acceleration control phase (for precise light-off achievement). This segmentation optimizes performance for each phase while maintaining overall system manageability.
Solution Approach 2:
The control system dynamically adapts its operating mode based on real-time conditions, transitioning from torque control to acceleration control as the engine progresses through startup. This dynamic adaptation enhances startup efficiency without requiring overly complex control architecture, as the mode transitions are based on clearly defined operating parameters.
3Loss of time
If the spool accelerates too quickly, then startup time is reduced, but the risk of exceeding target speed or causing mechanical stress increases
Solution Approach 1:
The control system continuously monitors spool speed and acceleration, using this feedback to adjust the starter torque in real-time. This feedback mechanism ensures the spool accelerates as quickly as possible while preventing excessive speed or mechanical stress, thereby reducing startup time without compromising reliability.
Solution Approach 2:
The acceleration control mode dynamically adjusts the spool acceleration rate based on real-time conditions, maintaining optimal acceleration throughout the startup sequence. This dynamic control prevents both overly conservative acceleration (which would increase startup time) and excessive acceleration (which would risk mechanical integrity), achieving the best balance between speed and reliability.
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 solution enables precise control of the spool's acceleration and speed, enhancing the likelihood of successful engine light-off and reducing the risk of engine failure during startup.
Implementation Method 1
at least one electric motor coupled to a respective spool
Data Source
AI summary
A starter assembly for a gas turbine engine may include, among other things, at least one electric motor coupled to a respective spool. A controller may be operable to modulate the at least one electric motor in a plurality of control modes. The control modes may include a torque control mode, an acceleration control mode and/or a speed control mode. A method for starting a gas turbine engine is also disclosed.