Screw Compressor Drive Control Using Operating-Point Torque Profiles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Screw compressors in refrigeration systems face challenges in efficiently managing torque profiles to reduce non-productive radial and axial forces, leading to pulsating torque and dynamic transmission of forces, which affects stability and efficiency.
Innovation Solution
A method is implemented to control screw compressors by receiving status signals, determining operating points, and selecting torque profiles based on these signals to drive the compressor, using a controller with sensors and an electric motor system to adjust torque delivery, thereby reducing non-productive forces and maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional constant torque drive is used, then the compressor operates continuously, but pulsating torque and non-productive radial/axial forces increase
Solution Approach 1:
The patent applies dynamics by transitioning from constant torque drive to variable torque profiling. The drive system dynamically adjusts torque delivery based on the compressor's instantaneous operating conditions, using measured suction and discharge pressures to calculate optimal torque profiles that reduce pulsating forces while maintaining continuous operation.
Solution Approach 2:
The patent implements parameter changes by modifying the torque parameter as a function of operating conditions. The controller changes torque delivery parameters based on real-time pressure measurements, calculating torque profiles that optimize performance and minimize harmful pulsating forces across different operating points.
2Object-generated harmful factors
If torque profiling is implemented to reduce pulsating torque, then harmful forces decrease, but control system complexity increases
Solution Approach 1:
The patent applies feedback by using pressure sensors to continuously monitor suction and discharge pressures, then feeding this information back to the controller. The controller calculates optimal torque profiles based on these feedback signals, creating a closed-loop system that reduces harmful forces without requiring overly complex control architecture.
Solution Approach 2:
The patent replaces complex mechanical torque management mechanisms with an electronic control system. Instead of using mechanical devices to physically adjust torque delivery, the system uses electronic controllers and sensors to calculate and deliver optimized torque profiles, simplifying the overall system while achieving the desired force reduction.
3Loss of energy
If operating point determination is used to select torque profiles, then efficiency improves, but measurement and detection difficulty increases
Solution Approach 1:
The patent applies universality by using a single pressure sensing system to serve multiple functions. The same suction and discharge pressure measurements used for basic compressor control also determine operating points for torque profile selection, eliminating the need for separate measurement systems and reducing overall complexity while improving energy efficiency.
Data Source
AI summary
An embodiment of method used to control operation of a screw compressor of a refrigeration system may include receiving status signals regarding operation of the screw compressor of the refrigeration system. The method may further include determining an operating point of the screw compressor based upon the received status signals, and selecting a torque profile for the screw compressor based upon the operating point. The method may also include driving the screw compressor per the selected torque profile. Refrigeration systems and compressor systems suitable for implementing the method are also presented.