APPARATUS AND METHOD FOR CONTROLLING TEMPERATURE OF SHOW CASE BY USING SUCTION PRESSURE OF COMPRESSOR

摘要

PURPOSE: An apparatus and method is provided to achieve a maximized cooling efficiency by minimizing frost formation at the cooling fin of the show case, and reduce power consumption by controlling the compressor in an optimized manner according to load. CONSTITUTION: An apparatus comprises a pressure sensor(10) for detecting pressure of the low pressure side pipeline of the compressor and converting the detected result into an analog signal; a key pad(20) for inputting operation pressure of the compressor and controlling operation state of the compressor; a sequence interface(30) for transmitting operation sequence of the compressor and operation state of an external device to a comparing/arithmetic unit(120); the comparing/arithmetic unit for calculating error pressure value based on the feedback value from the pressure sensor, control reference value as a basic rotational frequency of an induction motor(60), and value of command from the sequence interface; a variable voltage/frequency power unit(40) operating by the calculation result of the comparing/arithmetic unit; a power supply selection unit(100) for selecting power from the variable voltage/frequency power unit or commercial power in accordance with the calculation result of the comparing/arithmetic unit; and the induction motor driven by the power selected by the power supply selection unit.