Turbomachine Torque Control for Transient Response
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Solution Overview
Problem
Current turbomachines face challenges in optimizing response time and operability during transient phases due to design constraints, with existing control strategies lacking a clear and reproducible method for effectively controlling electric machines integrated into these systems.
Innovation Solution
A method involving a torque control loop that adjusts torque setpoints for electric machines based on fuel flow differences, allowing for improved operability and reduced power consumption, while supporting fuel control loops to manage surging and shutdown phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the operating line is placed as high as possible to optimize compressor performance, then the performance of compressors is improved, but the margin from operability limits is reduced
Solution Approach 1:
An electric machine acts as an intermediary device between the fuel control system and the spool dynamics. During transient phases, the electric machine provides additional torque to the spool, enabling the fuel flow to be increased more aggressively without exceeding operability limits, thus allowing the operating line to be placed higher while maintaining safety margins
Solution Approach 2:
The control method dynamically changes the torque parameter of the electric machine during transient phases. By adjusting the electric machine torque in real-time based on detected transient conditions, the system can rapidly change spool speed parameters, enabling faster response while maintaining operability margins
2Reliability
If the margin from operability limits is increased to allow safe accelerations and decelerations, then the operability and safety are improved, but the acceleration and deceleration time of the engine increases
Solution Approach 1:
The electric machine serves as a mediator that compensates for the reduced fuel flow margin. When operating closer to operability limits for faster response, the electric machine provides the necessary torque support to prevent exceeding safety thresholds, enabling rapid acceleration/deceleration while maintaining safety
Solution Approach 2:
The control method detects transient phases in advance and preliminarily activates the electric machine torque support. By detecting the onset of transient conditions and pre-positioning the electric machine to provide torque, the system prepares for rapid response before the transient phase fully develops, reducing overall response time
3Loss of time
If a torque control loop is implemented to regulate electric machine torque during transient phases, then the response time is improved, but the device complexity increases
Solution Approach 1:
The torque control loop is integrated into the existing fuel control loop architecture, making the control system multi-functional. The same control device that manages fuel flow also manages electric machine torque, eliminating the need for a completely separate control system and reducing overall complexity
Solution Approach 2:
The torque control loop uses feedback from the fuel control loop, specifically the flow difference signal, to regulate electric machine torque. This feedback mechanism allows the system to automatically adjust torque based on actual transient conditions without requiring complex external control systems
Data Source
AI summary
The invention relates to a method for controlling a turbomachine comprising a gas generator, the turbomachine comprising an electric machine forming a device for injecting torque into/removing torque from one of the low pressure/high pressure rotation shafts of said gas generator. Said method comprises a step of implementing a fuel control loop in order to determine a fuel flow setpoint into the combustion chamber, and comprising, in the event that at least one operability limit is reached, determining a corrected fuel flow setpoint, said corrected fuel flow setpoint exhibiting a difference in relation to the setpoint. Said method also comprises a step of implementing a torque control loop in order to determine a torque setpoint for the electric machine, and comprising determining a torque correction quantity as a function of said difference, said torque setpoint being determined as a function of said torque correction quantity.