Method of improved control for variable volume ratio valve
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Solution Overview
Problem
Variable volume ratio compressors experience excessive wear due to high-frequency switching of volume ratios, which can lead to inconsistent operation and reduced efficiency, especially under partial load conditions.
Innovation Solution
A system and method for controlling the volume ratio of a variable volume ratio compressor based on suction density and compressor speed, using a controller to determine a switching parameter and implement changes with incorporated delay periods to reduce frequent switching, thereby improving operational consistency and reducing wear on system components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automated switching of volume ratios is implemented to improve compressor efficiency under partial load conditions, then compressor efficiency is improved, but high-frequency switching occurs causing excessive wear on variable volume ratio system components
Solution Approach 1:
The patent implements periodic action by introducing delay periods between volume ratio switching decisions. The controller waits for a specified delay period after detecting a switching condition before actually executing the volume ratio change. This periodic action filters out high-frequency switching signals and ensures that only sustained operating conditions trigger volume ratio changes, thereby reducing excessive wear on components while maintaining compressor efficiency benefits.
2Productivity
If volume ratio switching is implemented to match compressor discharge conditions to condenser pressure conditions, then efficiency under partial load conditions is improved, but high-frequency switching occurs leading to inconsistent operation
Solution Approach 1:
The patent applies periodic action by implementing delay periods that filter out transient switching signals. The controller does not immediately respond to every detected switching condition but rather waits for the delay period to elapse, ensuring that only stable, sustained operating conditions trigger volume ratio changes. This stabilizes operational composition by preventing erratic switching while preserving the ability to adapt to genuine load changes.
3Adaptability or versatility
If frequent volume ratio changes are made to optimize compressor performance, then adaptability to varying load conditions is improved, but excessive wear on system components occurs
Solution Approach 1:
The patent resolves this contradiction by implementing periodic action through delay periods. The controller maintains adaptability to varying load conditions by still responding to genuine changes in operating parameters, but the delay period filters out transient or erroneous switching signals. This ensures that volume ratio changes occur only when necessary and sustained, preserving component lifespan while maintaining system adaptability to real load variations.
Data Source
AI summary
Variable volume ratio compressors may be controlled using a switching parameter based on compressor speed and suction density to improve the matching of compressor volume ratio to desired discharge conditions. Delay periods may be implemented in the determination of when to change volume ratio to control the frequency of changes to the volume ratio. The switching parameter may be a product of the compressor speed and suction density. The volume ratio of the compressor may be controlled by switching valves directing pressure to a piston of a variable volume ratio system of the compressor.