Compressor Surge Control Using ASD Speed and Power Mapping
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Solution Overview
Problem
Traditional surge control systems for electric motor driven compressors require multiple sensors and are costly, complex, and prone to equipment damage due to gas flow surges, necessitating a more reliable and cost-effective solution.
Innovation Solution
An adjustable speed drive (ASD) system powered by a three-phase electric power supply, connected between the electric motor and bypass valve, generates a two-dimensional surge map to detect surges and control the motor speed and power, eliminating the need for multiple sensors and providing redundant control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional surge control systems with multiple sensors are used, then surge detection capability is improved, but system complexity and cost increase
Solution Approach 1:
The ASD uses its own built-in sensors and control algorithms to detect surge conditions and adjust motor operation, eliminating the need for external surge detection sensors and controllers. The system serves itself by utilizing existing components for dual purposes.
Solution Approach 2:
The ASD performs multiple functions: it controls motor speed for compression requirements and simultaneously detects surge conditions and adjusts operation to prevent surge. This multi-functionality eliminates dedicated surge control hardware.
2Reliability
If traditional surge control systems with multiple sensors are used, then surge detection capability is improved, but system cost increases
Solution Approach 1:
The ASD uses its own built-in sensors and control algorithms to detect surge conditions and adjust motor operation, eliminating the need for external surge detection sensors and controllers. The system serves itself by utilizing existing components for dual purposes.
3Reliability
If bypass valve is used to relieve discharge pressure, then surge is controlled, but response time is delayed
Solution Approach 1:
The ASD detects surge conditions and preemptively adjusts motor speed to prevent surge from developing, rather than waiting for pressure buildup and then opening bypass valves. This preliminary action occurs before surge conditions fully develop.
Solution Approach 2:
The system dynamically adjusts motor speed in real-time based on continuous monitoring of operating conditions, enabling rapid response to changing surge risks without the mechanical delay of bypass valve operation.
4Reliability
If motor speed is adjusted to prevent surge, then surge control is improved, but compression output may be affected
Solution Approach 1:
The system dynamically adjusts motor speed in real-time based on continuous monitoring of operating conditions, enabling rapid response to changing surge risks without the mechanical delay of bypass valve operation.
Solution Approach 2:
The ASD continuously monitors operating conditions and uses feedback control to adjust motor speed, maintaining optimal compression output while preventing surge by making real-time adjustments based on actual system state.
Data Source
AI summary
A system and method for controlling gas surges in compressors powered by electric motors. An adjustable speed drive (ASD) incorporating a microprocessor powered by a three-phase source of electricity controls the electric motor which drives the compressor. A bypass valve is inserted between the gas input of the compressor and the gas discharge. The bypass valve opens in response to signals from the ASD which detects gas surges by analyzing a stored surge map which plots a surge line and a related discretionary control line based on the power and speed of the motor. When the operating point of the motor crosses the control line, the ASD causes the bypass valve to open.