Gas Turbine Control System Using Variable Geometry Feedback
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Solution Overview
Problem
In turbo-jet engines, significant differences between estimated and actual thermodynamic states during speed transitions can lead to compressor stallings, extinctions, or overspeeds, necessitating additional safety margins that increase mass and complexity.
Innovation Solution
A method and system for controlling a gas turbine that adjusts fuel flow thresholds in real-time based on the actual position of variable geometry components, optimizing thermodynamic state assessment by using detected position information to compute and correct threshold values for fuel flow and geometry positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional safety margins are introduced in the main control loop to prevent compressor stallings during speed transitions, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies feedback by using position sensors to detect the actual position of variable geometry portions and feeding this information back to the control system. This feedback loop enables real-time adjustment of threshold values based on actual engine state, improving reliability without requiring overly complex predetermined safety margins
Solution Approach 2:
The patent implements dynamic adjustment of threshold values in the main control loop based on detected position information from variable geometry portions. Instead of using fixed safety margins, the thresholds are dynamically modified according to actual engine operating conditions, maintaining reliability while reducing control system complexity
2Reliability
If additional safety margins are taken on computed thresholds during successive speed transitions, then reliability is improved, but loss of time increases due to slower acceleration
Solution Approach 1:
The patent dynamically adjusts threshold values based on detected position information from variable geometry portions during speed transitions. This allows the control system to optimize thresholds in real-time, enabling faster acceleration while maintaining compressor stalling prevention through adaptive rather than conservative fixed margins
Solution Approach 2:
The patent changes the parameter of threshold values from fixed predetermined values to dynamically adjusted values based on actual engine state. This parameter change allows the system to reduce unnecessary safety margins during acceleration, improving response time while maintaining reliability through real-time adaptation
3Ease of operation
If estimated thermodynamic state is used for computing thresholds, then ease of operation is improved, but measurement precision deteriorates due to significant differences from actual state
Solution Approach 1:
The patent uses feedback from position sensors on variable geometry portions to improve the accuracy of thermodynamic state estimation. The detected position information is fed back to refine threshold computations, maintaining ease of operation while significantly improving measurement precision compared to using estimated state alone
Solution Approach 2:
The patent introduces detected position information from variable geometry portions as an intermediary to bridge the gap between estimated and actual thermodynamic state. This intermediary data enables more accurate threshold computation without requiring direct measurement of all thermodynamic parameters, maintaining simplicity while improving precision
Data Source
AI summary
A method for controlling a gas turbine including a compressor assembly including at least one variable geometry portion, a combustion chamber, and a turbine assembly. The method generates a flow rate setpoint value for fuel to be fed to the combustion chamber as a function of a desired speed of the gas turbine, computes threshold values for maintaining the fuel flow setpoint value in a given range, the threshold values depending on a thermodynamic state of the gas turbine, and controls the position of the variable geometry portion by controlling an actuator as a function of the difference between position information representative of the instantaneous position and setpoint position information. The threshold values are automatically adjusted by computation in real time as a function of the instantaneous position information of the variable geometry portion or of the difference between this position information and the setpoint position information.