Variable-Speed Compressor Temperature Validation for Sensor Fault Detection

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Solution Overview

Problem

Existing refrigeration systems with variable speed compressors face challenges in accurately evaluating compressor and refrigeration system parameters, leading to potential malfunctions due to inaccurate temperature readings from sensors, which can result in inefficient operation and damage.

Innovation Solution

A system and method that utilize a control module to receive and analyze signals from condenser and evaporator sensors, calculate derived temperatures based on compressor power and speed data, and compare these with measured temperatures to detect inaccuracies, generating alarms for malfunctioning sensors and averaging temperatures for accurate parameter evaluation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple temperature calculation methods are used to cross-validate condenser temperature, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvecondenser temperature measurement accuracyVSAvoidtemperature evaluation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses feedback by comparing the first derived condenser temperature (from compressor parameters) with the second derived condenser temperature (from evaporator temperature and system parameters) to validate the accuracy of temperature measurements. This cross-validation feedback mechanism improves measurement precision without requiring additional sensors.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent creates multiple computational copies of temperature derivation methods - one based on compressor power and speed data, another based on evaporator temperature and system parameters. By comparing these computational copies, the system verifies measurement accuracy without physical duplication of sensors.

Inventive Principle:
Principle #26Copying

2Reliability

If derived temperature calculations are performed using multiple parameters, then reliability is improved, but loss of time increases

Engineering Contradiction:
Improveparameter evaluation reliabilityVSAvoidtemperature calculation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The control module continuously monitors and stores compressor power data, compressor speed data, and evaporator temperature data in real-time operation. This preliminary data collection ensures that when temperature validation is needed, all required parameters are already available, eliminating calculation delays while maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs continuous temperature derivation and validation operations using available real-time data from sensors and compressor measurements. This continuous operation ensures reliable temperature assessment without periodic interruptions or batch processing delays.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP2198160B1System and method for evaluating parameters for a refrigeration system with a variable speed compressor
Publication Date: 2018.09.19 EMERSON CLIMATE TECHNOLOGIES INC
  • EP2198160B1 patent drawingFigure 1
  • EP2198160B1 patent drawingFigure 2
  • EP2198160B1 patent drawingFigure 3

AI summary

A system and method for evaluating parameters for a refrigeration system having a variable speed compressor is provided. A compressor is connected to a condenser and an evaporator. A condenser sensor and an evaporator sensor are provided. An inverter drive modulates a frequency of electric power delivered to the compressor to modulate a speed of the compressor. A monitor module receives compressor power data and compressor speed data from the inverter drive, determines a measured condenser temperature based on the condenser signal, determines a measured evaporator temperature based on the evaporator signal, calculates a first derived condenser temperature based on the compressor power data and the compressor speed data, calculates a second derived condenser temperature based on the measured evaporator temperature, the compressor power data and the compressor speed data, and compares the measured condenser temperature with the first and second derived condenser temperatures to determine whether any of the measured condenser temperature and the first and second derived condenser temperatures are inaccurate.