Compressor Capacity Stage Control Using Predicted Average Values
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control logic methods for refrigerant compressor systems in heat pumping circuits are not responsive enough to changes in capacity set values, leading to inefficiencies and potential wear on components.
Innovation Solution
A method that uses a calculated capacity average value, determined through exponential moving averages, to compare with a decision quantity, allowing for adaptive adjustment of compressor capacity stages and incorporating change rate limitation actions to prevent excessive switching, thereby enhancing responsiveness and system stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional control logic methods are used for compressor capacity adjustment, then the control system is simple to implement, but the system response speed to capacity changes is too slow
Solution Approach 1:
The patent applies preliminary action by calculating a predicted capacity average value based on historical capacity selection signals before the actual capacity change occurs. This prediction allows the control system to prepare for upcoming capacity adjustments, improving response speed without requiring complex real-time control mechanisms. The predicted value is computed in advance using a moving average algorithm, enabling proactive rather than reactive control.
Solution Approach 2:
The patent implements feedback by continuously comparing the predicted capacity average value with the current capacity selection signal and using this comparison to determine whether to adjust the compressor capacity. This closed-loop feedback mechanism ensures the system responds appropriately to actual capacity requirements while maintaining stability through systematic decision-making based on historical data patterns.
2Speed
If frequent capacity stage changes are made to respond quickly to capacity set value changes, then the system responsiveness improves, but component wear increases
Solution Approach 1:
The patent applies dynamics by implementing a dynamic threshold comparison mechanism where the predicted capacity average value is compared against the current capacity selection signal. This dynamic approach allows the system to adapt its response based on actual capacity requirements rather than following a fixed switching schedule, improving responsiveness while avoiding unnecessary adjustments that would increase component wear.
Solution Approach 2:
The patent implements periodic action through the moving average calculation that processes capacity selection signals over a defined time period. This periodic processing smooths out short-term fluctuations and prevents excessive switching by only triggering capacity changes when sustained trends indicate actual capacity requirements have changed, thereby extending component lifespan while maintaining adequate system responsiveness.
3Adaptability or versatility
If the compressor capacity stage is changed frequently to match capacity set value changes, then the system adapts quickly to load changes, but unnecessary adjustments increase system instability
Solution Approach 1:
The patent introduces an intermediary element - the predicted capacity average value - that mediates between the raw capacity selection signals and the actual capacity stage changes. This intermediary smooths out signal fluctuations and provides a more stable basis for decision-making, allowing the system to adapt to genuine load changes while filtering out noise that would cause unnecessary adjustments and instability.
Solution Approach 2:
The patent applies parameter changes by transforming the raw capacity selection signal into a predicted capacity average value through mathematical processing. This parameter transformation changes the nature of the input data from potentially fluctuating instantaneous values to a smoothed, trend-based metric, enabling more stable and reliable capacity stage decisions while maintaining adaptability to actual load requirements.
Data Source
AI summary
Method for controlling a compressor system, arranged in a heat pumping circuit, said compressor system being designed to be operated at at least two different compressor capacity stages, said compressor capacity stages being adjusted by a capacity adjustment system enabling switching from one compressor capacity stage to another compressor capacity stage, said capacity adjustment system being controlled by a capacity selection signal defining the compressor capacity stage to be selected, said method comprising determining a capacity set value, determining a decision quantity on the basis of said capacity set value, determining a calculated capacity average value on the basis of capacity selection signals generated before, comparing said calculated capacity average value with said decision quantity and changing said compressor capacity stage to the next higher stage if the calculated capacity average value is below the decision quantity or changing said compressor capacity stage to the next lower stage if the calculated capacity average value is above the decision quantity, or not changing said compressor capacity stage if the calculated capacity average value meets said decision quantity.