System and method for calibrating parameters for a refrigeration system with a variable speed compressor
View Patent ↗A system and method for calibrating 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 outputs a condenser signal corresponding to at least one of a sensed condenser pressure and a sensed condenser temperature. An inverter drive modulates a frequency of electric power delivered to the compressor to modulate a speed of the compressor. A control module is connected to the inverter drive and determines a measured condenser temperature based on the condenser signal, monitors electric power data and compressor speed data from the inverter drive, calculates a derived condenser temperature based on the electric power data, the compressor speed data, and compressor map data for the compressor, compares the measured condenser temperature with the derived condenser temperature, and updates the compressor map data based on the comparison.
1. A system comprising:
a compressor connected to a condenser and an evaporator;
a condenser sensor that outputs a condenser signal corresponding to at least one of a sensed condenser pressure and a sensed condenser temperature;
an inverter drive that modulates a frequency of electric power delivered to said compressor to modulate a speed of said compressor;
a control module connected to said inverter drive that determines a measured condenser temperature based on said condenser signal, that monitors electric power data and compressor speed data from said inverter drive, that calculates a derived condenser temperature based on said monitored electric power data, said monitored compressor speed data, and compressor map data for said compressor, said compressor map data functionally correlating electric power data and compressor speed data with condenser temperature data for said compressor, and that compares said measured condenser temperature with said derived condenser temperature, and selectively updates said compressor map data based on said comparison.
2. The system of claim 1 wherein said control module calculates a difference between said derived condenser temperature and said calculated condenser temperature, compares said difference with a predetermined threshold, and selects one of said derived condenser temperature and said calculated condenser temperature as being more accurate when said difference is greater than said predetermined threshold.
3. The system of claim 2 wherein said control module generates an alarm when said difference is greater than said predetermined threshold.
4. A method comprising:
receiving a condenser signal corresponding to at least one of a condenser pressure and a condenser temperature of a condenser connected to a compressor and an evaporator;
modulating a speed of said compressor with an inverter drive configured to modulate a frequency of electric power delivered to said compressor;
receiving electric power data and compressor speed data from said inverter drive;
calculating a derived condenser temperature based on said received electric power data, said received compressor speed data, and compressor map data associated with said compressor, said compressor map data functionally correlating electric power data and compressor speed data with condenser temperature data for said compressor;
determining a measured condenser temperature based on said condenser signal;
comparing said derived condenser temperature with said measured condenser temperature; and
selectively updating said compressor map data based on said comparing.
5. The method of claim 4 further comprising calculating a difference between said derived condenser temperature and said calculated condenser temperature, comparing said difference with a predetermined threshold, and selecting one of said derived condenser temperature and said calculated condenser temperature as being more accurate when said difference is greater than said predetermined threshold.
6. The method of claim 4 further comprising generating an alarm when said difference is greater than said predetermined threshold.
7. A system comprising:
a compressor connected to a condenser and an evaporator;
an evaporator sensor that outputs an evaporator signal corresponding to at least one of a sensed evaporator pressure and a sensed evaporator temperature;
a discharge temperature sensor that outputs a discharge temperature signal corresponding to a temperature of refrigerant exiting said compressor;
an inverter drive that modulates a frequency of electric power delivered to said compressor to modulate a speed of said compressor;
a control module connected to said inverter drive that determines a measured evaporator temperature based on said evaporator signal, that monitors electric power data and compressor speed data from said inverter drive, that calculates a derived evaporator temperature based on said monitored electric power data, said monitored compressor speed data, said discharge temperature signal, and compressor map data for said compressor, said compressor map data functionally correlating electric power data, compressor speed data, and discharge temperature data with evaporator temperature data for said compressor, that compares said measured condenser temperature with said derived condenser temperature, and that selectively updates said compressor map data based on said comparison.
8. The system of claim 7 wherein said control module calculates a difference between said derived evaporator temperature and said calculated evaporator temperature, compares said difference with a predetermined threshold, and selects one of said derived evaporator temperature and said calculated evaporator temperature as being more accurate when said difference is greater than said predetermined threshold.
9. The system of claim 8 wherein said control module generates an alarm when said difference is greater than said predetermined threshold.