Compressor Surge Prevention via Power Converter Torque Control
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Solution Overview
Problem
Conventional methods for detecting and preventing surge states in compressors are slow and often result in damage to compressor blades due to delayed detection, as they only identify flow separation after it has begun, leading to frequent overhauls and pressure fluctuations.
Innovation Solution
A method using a power converter to monitor the compressor's actual rotational speed and active current component, generating a control signal based on stored torque characteristic curves to quickly determine and exit an impermissible operating state, reducing the duration and intensity of surge states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional detection methods using pressure difference and volumetric flow are used, then surge states can be detected, but detection occurs only after flow separation has already started causing blade damage
Solution Approach 1:
The patent applies preliminary action by detecting surge states before flow separation causes blade damage. This is achieved by using a power converter to monitor the compressor's actual rotational speed and active current component, generating a control signal based on stored torque characteristic curves to quickly determine and exit impermissible operating states, reducing the duration and intensity of surge states before physical damage occurs
2Reliability
If mechanical actuators at compressor inlet are used to reduce differential pressure, then surge can be prevented, but the actuator's slow response time in seconds delays the prevention
Solution Approach 1:
The patent replaces the mechanical actuator system with an electrical control system. Instead of using mechanical actuators that respond in seconds, the invention uses a power converter with direct torque control that monitors rotational speed and current components, generating control signals based on torque characteristic curves. This substitution enables response times in milliseconds rather than seconds, dramatically improving the speed of surge prevention
3Measurement precision
If additional measuring devices are installed to improve detection accuracy, then surge detection may be improved, but device complexity and cost increase
Solution Approach 1:
The patent applies self-service by utilizing existing drive variables (rotational speed and active current component from the power converter) that are already available in the system. Instead of adding new measuring devices, the invention uses the power converter's existing sensors and control capabilities to detect surge states by comparing actual operating parameters against stored torque characteristic curves, thereby improving detection accuracy without increasing device complexity
Data Source
AI summary
A method for operation of a compressor supplied by a power converter having an operating condition (BV) for the compressor (12) supplied by a power converter, generated from a measured actual rotational speed (n) of the compressor and a given effective current component (iW) of a measured power converter output current (I) using a stored speed-dependent pump characteristic curve (SG) monitored for validity such that on determining invalidity, as per a stored speed-dependent instantaneous curve, a control signal (SSG) for reducing a torque (M) is generated. A method for operation of a compressor supplied by a power converter is then achieved with which the duration and the intensity of surge conditions is significantly reduced.