Compressor Control System IGV ASV Surge Prevention
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Solution Overview
Problem
Compressor systems face instability due to the coupling phenomenon between inlet guide vane (IGV) and anti-surge valve (ASV) control operations, leading to pressure hunting and fluctuating flow, which can result in mechanical vibration and damage, and are challenging to control effectively.
Innovation Solution
A compressor control system that includes an IGV and an ASV, with a controller generating supplementary surge control signals and performance control signals to minimize mutual influence between IGV and ASV operations, allowing for stable compressor operation by setting a supplementary surge control range between the surge control range and the surge range, and operating the IGV in an anti-surge mode to prevent surge occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both IGV and ASV operate together to control compressor, then pressure control is achieved, but coupling phenomenon occurs causing pressure hunting and flow fluctuation
Solution Approach 1:
The control system is segmented into distinct operational modes: surge control mode (when operating point enters surge control range) and performance control mode (normal operation). This segmentation prevents the coupling phenomenon by ensuring only one control mechanism operates at a time, eliminating pressure hunting and flow fluctuation while maintaining both pressure control stability and operational stability.
Solution Approach 2:
The control system dynamically switches between surge control mode and performance control mode based on the operating point's position relative to the surge control range. This dynamic adaptation allows the system to provide surge prevention when needed while maintaining optimal performance during normal operation, resolving the contradiction between pressure control and operational stability.
2Stress or pressure
If IGV is closed to increase pressure, then outlet pressure increases, but operating point moves toward surge range increasing surge risk
Solution Approach 1:
The ASV acts as an intermediary control element that can increase outlet pressure by reducing resistance in the bypass line without moving the operating point toward the surge range. This resolves the contradiction by providing an alternative mechanism to increase pressure that does not have the adverse effect of triggering surge conditions.
Solution Approach 2:
The control system changes the operational parameters by switching between different control modes based on the operating point position. When in surge control mode, the system prioritizes surge prevention by controlling the ASV to adjust pressure without compromising reliability, thus resolving the contradiction between pressure increase and surge prevention.
3Reliability
If ASV opens to prevent surge, then flow increases and pressure decreases, but this may conflict with IGV pressure control direction
Solution Approach 1:
The control system segments operational priorities by mode: in surge control mode, surge prevention is the primary objective and IGV control is suspended; in performance control mode, pressure control is prioritized. This segmentation eliminates conflicts between ASV and IGV control directions while ensuring both surge prevention and pressure control are achieved in their respective operational contexts.
Solution Approach 2:
The control system continuously monitors the operating point's position relative to the surge control range and provides feedback to determine the appropriate control mode. This feedback mechanism ensures that the system responds appropriately to changing conditions, preventing surge when the operating point approaches the surge range while maintaining pressure control during normal operation.
Data Source
AI summary
A compressor control system includes: a compressor; an inlet guide vane (IGV) arranged at an inlet of the compressor, and configured to adjust opening of the inlet based on a supplementary surge control signal or a performance control signal; an anti-surge valve (ASV) connected to an outlet of the compressor, and configured to prevent a surge based on a surge control signal; and a controller configured to generate the surge control signal for controlling the ASV when an operating point enters a surge control range, generate the supplementary surge control signal for controlling the IGV in an anti-surge mode when the operating point enters a supplementary surge control range set between the surge control range and a surge range, and generate the performance control signal for controlling the IGV in a performance mode until the operating point enters the surge control range.