Gas Turbine Fuel Metering Valve Control via Dynamic Gain Scheduling
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Solution Overview
Problem
Gas turbine engines experience long startup times and fluctuations in null current values due to existing proportional and integral control loop configurations, which affect the precision and responsiveness of fuel metering valve positioning.
Innovation Solution
A method that determines an error value between a demand and actual position of a fuel metering valve, using scheduling parameters to update integral and proportional gains through scalers, and calculates a null current value by summing these gains along with an offset, enhancing real-time control and consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a proportional and integral control loop is used to control the fuel metering valve position, then the valve position can be controlled, but long startup times and fluctuations in null current value occur
Solution Approach 1:
The control system dynamically adjusts the proportional and integral gains based on the operating state of the gas turbine engine. The controller determines whether the engine is in a transient state (during startup/transient operation) or steady state, and switches between different gain values accordingly. This dynamic adaptation resolves the contradiction by using higher integral gains during transient states to reduce startup time, while using lower gains during steady state to maintain null current consistency.
Solution Approach 2:
The invention changes the control parameters (proportional and integral gains) based on the engine's operating conditions. During transient operation, the controller uses a first proportional gain and a first integral gain that are optimized for rapid response. During steady state, it switches to a second proportional gain and a second integral gain that are optimized for stability and consistency. This parameter switching resolves the contradiction between fast startup and stable operation.
2Productivity
If fixed proportional and integral gains are used in the control loop, then the control system is simple, but the response is slow and null current values fluctuate
Solution Approach 1:
The control system transitions from fixed gains to dynamic gains that adapt to operating conditions. The controller monitors engine state and automatically selects appropriate gain values, achieving fast response during transient states without requiring complex manual tuning or overly sophisticated control algorithms. This resolves the contradiction by implementing a moderately complex dynamic system that delivers high productivity.
Data Source
AI summary
A method for controlling a position actuation system component in a gas turbine engine based on a modified proportional and integral control loop is provided. The method includes determining an error value between a demand signal for the position actuation system component and a position signal for the position actuation system component. The method also includes determining an integral gain scaler as a function of a scheduling parameter value and determining an integral gain based on the determined error value and the determined integral gain scaler. Additionally the method includes determining a proportional gain scaler as a function of the scheduling parameter value and determining a proportional gain based on the determined error value and the determined proportional portion gain scaler. The method adds the determined integral gain with the determined proportional gain to determine a null current value for the position actuation system component.