Variable-Speed Compressor Control for Floodback and Overheating
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Solution Overview
Problem
Variable speed compressors face issues with flood back and overheating conditions, which can damage internal components and reduce lubrication, leading to inefficient operation in refrigeration systems.
Innovation Solution
A control module connected to an inverter drive that monitors compressor power and speed data, calculates saturated condenser temperature, and adjusts compressor speed and expansion valve operation to maintain the compressor within predetermined operating envelopes, preventing flood back and overheating by using sensors for discharge and suction temperature signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor operates at variable speeds to match refrigeration system load, then energy efficiency and capacity control are improved, but the risk of flood back and overheating conditions increases
Solution Approach 1:
The control module continuously monitors compressor operating conditions including power data, speed data, and calculated saturated condenser temperature. This feedback mechanism allows the system to detect flood back and overheating conditions in real-time and adjust compressor speed accordingly, resolving the contradiction by enabling both variable speed operation and protective control.
Solution Approach 2:
The system uses the inverter drive's own power and speed data to calculate saturated condenser temperature and detect abnormal conditions, eliminating the need for additional expensive sensors. The compressor essentially monitors and protects itself using readily available operational parameters.
2Measurement precision
If traditional temperature sensors are used to monitor compressor conditions, then detection accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The patent replaces physical temperature sensors with a computational approach that calculates saturated condenser temperature using electrical power data and speed data from the inverter drive. This substitution eliminates mechanical sensing components while achieving the necessary monitoring function through mathematical relationships between power, speed, and temperature.
Solution Approach 2:
The control module acts as an intermediary that transforms readily available electrical parameters (power and speed data) into meaningful thermal information (saturated condenser temperature). This intermediary calculation approach provides temperature monitoring without direct thermal contact or additional sensing hardware.
Data Source
AI summary
A system and method for a compressor may include an inverter drive connected to the compressor that receives electric power and modulates a speed of the compressor by modulating a frequency of the electric power. A control module connected to the inverter drive monitors compressor power data and compressor speed data from the inverter drive, and calculates a saturated condenser temperature of a refrigeration system associated with the compressor based on the compressor power data and the compressor speed data.