Control device, refrigeration system, control method, and control program
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Solution Overview
Problem
Existing air conditioner malfunction detection systems struggle to accurately identify compressor abnormalities due to complexities in setting threshold values for frequency component changes, which are influenced by sensor errors and environmental factors, leading to inaccurate detection.
Innovation Solution
A control device that estimates the state of a compressor by monitoring the magnitude of temporal changes in specific frequency components, allowing for precise identification of rapid changes indicative of compressor abnormalities such as seal failure or liquid compression, without requiring additional sensors or complex algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If frequency analysis is performed on motor current to detect compressor abnormalities, then detection capability is improved, but detection accuracy deteriorates due to threshold setting complexities influenced by sensor errors and environmental factors
Solution Approach 1:
The patent transforms the detection approach by changing from absolute threshold comparison to relative change rate analysis. Instead of comparing frequency component values against fixed thresholds that are sensitive to sensor errors and environmental factors, the system calculates the rate of change of frequency components over time. This parameter transformation makes the detection immune to absolute value variations caused by sensor drift or environmental conditions, while maintaining sensitivity to actual abnormality-induced changes.
Solution Approach 2:
The patent introduces dynamic analysis by continuously monitoring the temporal changes of frequency components rather than using static threshold values. The system calculates the change rate of frequency components in real-time, allowing the detection criterion to adapt to varying operating conditions. This dynamic approach enables accurate detection across different environmental conditions without requiring multiple static thresholds for each condition.
2Measurement precision
If comprehensive frequency analysis is performed to accurately detect compressor abnormalities, then detection accuracy is improved, but computational load and system complexity increase
Solution Approach 1:
The patent extracts only the essential information needed for detection by focusing specifically on the change rate of frequency components rather than analyzing the complete frequency spectrum in detail. By isolating the temporal derivative of frequency components as the key detection parameter, the system achieves accurate abnormality detection while minimizing computational requirements. This extraction approach eliminates the need for complex multi-parameter analysis while maintaining detection effectiveness.
Data Source
AI summary
In a system including a compressor including a motor and a compression mechanism, processing circuitry performs handling processing including at least one of output processing for outputting information indicating that the compressor is in a predetermined state and changing processing for changing an operating condition of the system in a case where an index value indicative of a magnitude of a temporal change of a specific frequency component included in a physical amount correlated with a state of the compressor and a predetermined threshold value satisfy a predetermined relationship.