Compressor Rack Capacity Control with One Active Variable Compressor
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Solution Overview
Problem
Existing refrigeration systems with multiple compressors face challenges in optimally controlling compressor racks with variable capacity components, leading to unpredictable operation and inefficient capacity modulation due to concurrent operation of multiple pulse width modulated devices.
Innovation Solution
A control algorithm utilizing a neural network to select and manage a single variable capacity component as the active component, prioritizing the component with the largest capacity range to minimize switching and maintain flexibility, while deactivating other components to prevent pump-down conditions and ensure efficient capacity modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple variable capacity components operate concurrently in a compressor rack, then the system can provide greater total capacity and flexibility, but the operation becomes unpredictable and control precision deteriorates
Solution Approach 1:
The patent segments the compressor rack control by designating one specific variable capacity component as the 'active' component while keeping other variable capacity components in fixed capacity mode. This segmentation isolates the pulse width modulation control to a single device, eliminating the unpredictable interactions that occur when multiple variable capacity components operate concurrently, thereby maintaining control precision while preserving overall system flexibility through the active component's variable capacity range.
2Productivity
If multiple variable capacity components are used in the compressor rack, then the system can modulate capacity more effectively, but device complexity and control difficulty increase
Solution Approach 1:
The patent applies local quality by giving different operational modes to different components within the compressor rack. Specifically, one variable capacity component is designated as 'active' with pulse width modulation capability for fine-grained capacity control, while other variable capacity components operate in a simpler fixed capacity mode. This differentiated approach maintains effective capacity modulation through the active component while reducing overall control complexity by limiting sophisticated control to a single device.
3Loss of energy
If variable capacity components are frequently switched to maintain optimal operation, then system efficiency improves, but reliability decreases due to increased wear and pump-down risks
Solution Approach 1:
The patent implements preliminary action by establishing a designation system that identifies which variable capacity component will serve as the active component before operational needs arise. This pre-designation prevents frequent switching between multiple variable capacity components, thereby reducing mechanical wear and the risk of pump-down conditions while maintaining system efficiency through the continuous availability of variable capacity control via the pre-selected active component.
4Reliability
If a single variable capacity component is designated as active, then control stability and reliability improve, but the system loses some capacity flexibility compared to using all variable capacity components
Solution Approach 1:
The patent applies universality by ensuring that the active variable capacity component has a sufficiently large variable capacity range that can accommodate the majority of system load variations. Additionally, the system can switch the active designation between different variable capacity components based on operational conditions, effectively providing multi-functionality across the compressor rack. This approach maintains control stability through single-component pulse width modulation while preserving overall capacity flexibility through the combined range of all variable capacity components.
Data Source
AI summary
A system and method of controlling a compressor rack having a plurality of variable capacity components is provided. A variable capacity component is selected from the plurality of variable capacity components as a designated variable capacity component. The designated variable capacity component is operated by varying a capacity of the designated variable capacity component. Each variable capacity component of the plurality of variable capacity components, except for the designated variable capacity component, is operated at a fixed capacity corresponding to one of a maximum and a minimum capacity of the variable capacity component.