Compressor Surge Control Using ASD Electrical Parameter Detection
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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, which necessitate a more efficient and reliable solution.
Innovation Solution
An adjustable speed drive (ASD) system with a microprocessor, powered by a three-phase electric power supply, generates a two-dimensional surge map to detect surges and control the bypass valve, reducing the need for multiple sensors and providing redundant control by modifying motor speed and power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional surge control systems use multiple sensors and complex control mechanisms, then surge detection capability is improved, but system complexity and cost increase
Solution Approach 1:
The patent combines surge detection and control functions into the existing ASD microprocessor, merging multiple functions (motor control, surge detection, surge control) into a single integrated system. This eliminates the need for separate surge controllers and multiple sensors, reducing system complexity while maintaining surge detection capability through analysis of electrical parameters already being monitored by the ASD.
Solution Approach 2:
The ASD microprocessor is made multi-functional by enabling it to perform not only motor speed control but also surge detection and surge control functions. The system uses the ASD's existing electrical parameter measurements (current, power, torque) for both motor control and surge detection purposes, making the device universal and eliminating the need for dedicated surge control hardware.
2Measurement precision
If traditional surge control systems use multiple sensors and complex mechanisms, then surge control accuracy is improved, but cost increases
Solution Approach 1:
The system uses the ASD's own electrical parameter measurements (current, power, torque) to detect and control surge conditions. The ASD essentially monitors itself and uses its existing operational data for surge detection, eliminating the need for external sensors and reducing system cost while maintaining control accuracy through the relationship between electrical parameters and compressor operating conditions.
Solution Approach 2:
The patent replaces mechanical/sensor-based surge detection systems with an electrical parameter-based detection system using the ASD's microprocessor. Instead of using physical sensors to measure pressure and flow, the system uses electrical measurements (current, power, torque) already available from the motor drive to infer surge conditions, substituting a simpler electrical system for a more complex mechanical sensing system.
3Reliability
If bypass valve is used to relieve discharge pressure during surge, then surge damage is prevented, but system complexity and cost increase
Solution Approach 1:
The bypass valve control function is merged with the ASD's existing control capabilities. The ASD microprocessor directly controls the bypass valve based on surge detection, combining motor control and valve control into a single integrated system. This eliminates the need for separate surge controllers and reduces control system complexity while maintaining compressor protection through coordinated speed and valve control.
4Speed
If ASD controls motor speed and torque directly, then response time to surge is reduced, but system complexity increases
Solution Approach 1:
The ASD integrates motor speed control and surge control functions into a single microprocessor-based system. By merging these functions, the system achieves fast response to surge conditions through direct electronic control of motor speed and torque, while the integration actually reduces overall system complexity compared to having separate control systems for motor and bypass valve.
Data Source
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Figure 2
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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.