Compressor Control Device Detecting Frequency Change Rate

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Solution Overview

Problem

Existing methods for detecting compressor malfunctions based on specific frequency components struggle to accurately handle rapid changes in these components, making it difficult to appropriately manage compressor states.

Innovation Solution

A control device that performs handling processing when an index value indicative of the magnitude of a temporal change in specific frequency components exceeds a predetermined threshold, allowing for appropriate management of compressor states, particularly in cases where sealability of the compression chamber fails or liquid compression occurs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the magnitude of the specific frequency component is compared with a threshold value, then the detection method is simple, but it is difficult to appropriately handle cases where the compressor is in a predetermined state with rapid changes in the specific frequency component

Engineering Contradiction:
Improvedetection method simplicityVSAvoidcompressor state detection accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the detection parameter from the absolute magnitude of the specific frequency component to the magnitude of its temporal change (derivative). This allows the system to detect rapid changes in compressor state that simple threshold comparison of static values would miss, while maintaining computational simplicity through basic differentiation and comparison operations.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the threshold value is set to detect rapid changes in specific frequency component, then the detection accuracy for predetermined states improves, but false detection may increase due to normal fluctuations

Engineering Contradiction:
Improvecompressor state detection accuracyVSAvoidfalse detection
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces dynamic threshold adjustment based on the operating conditions of the compressor. The threshold is not fixed but adapts to normal fluctuations in different operating states, allowing accurate detection of abnormal rapid changes while accommodating legitimate variations in compressor performance under different loads and conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the compressor's operating conditions to adjust detection parameters. By continuously monitoring operating state and adjusting the threshold accordingly, the system distinguishes between normal fluctuations and actual abnormalities, reducing false detections while maintaining high detection accuracy for genuine issues.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4693886A1Control device, refrigeration system, control method, and control program
Publication Date: 2026.02.11 DAIKIN INDUSTRIES LTD
  • EP4693886A1 patent drawingFigure 1
  • EP4693886A1 patent drawingFigure 2
  • EP4693886A1 patent drawingFigure 3~4

AI summary

In a system including a compressor (50) including a motor (60) and a compression mechanism (65), a control unit (31) performs handling processing including at least one of output processing for outputting information indicating that the compressor (50) 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 (50) and a predetermined threshold value satisfy a predetermined relationship.