Screw Compressor Torque Profile Control for Pressure Stability
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Solution Overview
Problem
Existing refrigeration systems with screw compressors face inefficiencies in energy consumption and operational control, particularly in maintaining optimal pressure differences and managing torque to reduce non-productive radial and axial forces, leading to suboptimal performance.
Innovation Solution
A method for controlling screw compressors in refrigeration systems involves receiving status signals to determine the operating point and selecting a torque profile, which is then used to drive the compressor, utilizing a controller and sensors to adjust the electric motor's torque output, thereby optimizing energy use and reducing non-productive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compressor motor speed is controlled through a frequency converter to maintain optimal pressure difference, then energy consumption is optimized, but the system complexity increases due to additional control devices
Solution Approach 1:
The control system continuously monitors operating conditions (pressure difference, temperature, power consumption) and adjusts the torque profile accordingly. This closed-loop feedback mechanism enables the system to maintain optimal energy efficiency by adapting to changing operating conditions, resolving the contradiction between energy optimization and system complexity through intelligent control.
Solution Approach 2:
The system dynamically adjusts the torque profile based on real-time operating conditions rather than using fixed control parameters. This dynamic adaptation allows the compressor to operate efficiently across varying loads and conditions, achieving energy optimization without requiring overly complex static control structures.
2Reliability
If torque control is implemented to reduce non-productive radial and axial forces, then compressor performance and reliability improve, but the control apparatus complexity increases
Solution Approach 1:
The system changes the torque parameter dynamically based on operating conditions to minimize non-productive forces. By adjusting torque as a variable parameter rather than maintaining a constant value, the system reduces radial and axial forces that do not contribute to compression, thereby improving reliability without requiring fundamentally new control hardware.
Solution Approach 2:
The patent replaces complex mechanical force management with electrical torque control through the frequency converter. Instead of using mechanical mechanisms to manage radial and axial forces, the system uses electrical control to adjust motor torque, simplifying the physical apparatus while achieving the same reliability improvement.
3Measurement precision
If multiple status signals are monitored to determine operating point and select torque profile, then operational control precision improves, but the measurement and control complexity increases
Solution Approach 1:
The control system is designed to handle multiple status signals (pressure, temperature, power consumption, operating point) through a single integrated control apparatus. This multi-functional approach allows precise operating point determination without requiring separate dedicated systems for each measurement, reducing overall complexity while maintaining high measurement precision.
Data Source
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AI summary
Method and control system for controlling an electric motor and a compressor system of a refrigeration system, comprising a memory with a plurality of stored torque profiles for the compressor; and a controller. The controller is configured to (a) receive status signals regarding a pulsing torque generated by the compressor system, (b) determine an operating point of the compressor system based upon the received status signals, (c) determine a torque profile for the compressor system based upon the operating point and the plurality of stored torque profiles, and (d) generate one or more control signals, per the determined torque profile, that adjust torque applied by an electric motor to the compressor per the determined torque profile.