Anti-Surge Valve Dead Time Compensation
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Solution Overview
Problem
Conventional anti-surge control systems in compressors suffer from dead time delays, leading to instability and reduced dynamic performance due to the non-linearity of the anti-surge valve actuator and fluid transport delays, resulting in potential catastrophic failures.
Innovation Solution
A model-based anti-surge dead time compensation method that uses a deterministic model to predict the anti-surge parameter, accounting for the impact of the anti-surge valve position, and adjusts the valve position to prevent over-correction or under-correction by calculating a corrected value of the anti-surge parameter, which is then used to determine a new position for the anti-surge valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional anti-surge control is used without dead time compensation, then the control system is simpler, but the system stability deteriorates and oscillations occur
Solution Approach 1:
The patent applies preliminary action by calculating and applying dead time compensation in advance. The controller computes the compensated setpoint using the deterministic model before the actual valve action occurs, effectively preparing the control signal ahead of time to account for the known dead time delay. This prevents oscillations and improves stability without requiring complex hardware modifications.
2Reliability
If dead time compensation is applied using deterministic model, then system stability improves, but computational complexity increases
Solution Approach 1:
The patent applies parameter changes by using a deterministic model that relates anti-surge parameter to valve position and system state. The controller dynamically adjusts the setpoint parameter based on current operating conditions (flow rates, pressures, valve position) to compensate for dead time effects. This model-based approach provides stable control with moderate computational requirements compared to more complex adaptive or neural network approaches.
3Measurement precision
If anti-surge valve actuator non-linearity is present, then valve response is simpler mechanically, but control precision deteriorates due to dead time effects
Solution Approach 1:
The patent applies feedback by continuously monitoring the actual anti-surge parameter (based on measured flow rates and pressures) and comparing it with the predicted value from the deterministic model. The controller uses this feedback to adjust the compensated setpoint, ensuring precise control despite the non-linear actuator characteristics and dead time delays. The feedback loop maintains accuracy without requiring complex mechanical actuator design.
Data Source
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AI summary
Methods (400) and devices (140, 150) for performing a model based anti-surge dead time compensation in systems (100) including a compressor (110) and an anti-surge loop (120) are provided. A new position of an anti-surge valve (130) on the anti-surge loop (120) is determined by correcting for dead time a value of the anti-surge parameter calculated from field measurements, based on a predicted anti-surge parameter estimated using a deterministic model which has as variables the field measurements and a current position of the anti-surge valve (130).