compressor, inverter, restart, refrigerator, suction, discharge, pressure, variable speed, control board, inverter software
When a short power cut or electricity failure occurs on an electric supply system, which the household refrigerator is connected to, the suction and discharge pressures of the system become unbalanced, and the compressor exposes to higher loads than rated conditions. If the power recovers very quickly before the pressures get balanced, the compressor may not overcome the load and fails to start up. If the inverter control of the compressor has Class B protection software instead of mechanical overload protector; the inverter software forms a fault signal, cuts the energy through the compressor and waits for a while that provides pressure balancing before the next compressor start up trial. Provided that the compressor starts up, or the inverter control cuts energy by a fault signal, the compressor periodically tries running in an infinite loop. This situation prevents compressor running and cooling of the refrigerator. In order to prevent this, the inverter board and the control software should be controlled at every load condition if it works properly or not. Generally, a standard restart test is done to refrigerators by cutting the electricity off and energizing after a few seconds in order to check if the compressor starts up or a fault signal occurs. This test only checks one load condition and every different suction-discharge pressure value after power cut cannot be simulated that can occur in the field. Simulation of all loads on the refrigerator is a hard situation because providing variable suction-discharge pressure values on the refrigerator system is impossible and waiting for pressure balancing takes a long time for every load condition. For this paper; a compressor restart test is studied without a refrigerator and an array of suction-discharge pressures that can occur against the compressor is determined in case of a short power off-on situation in order to check all load conditions of the refrigerator. The test is carried out by compressor-electronic control pairs on a cooling system simulator. The compressor test results are verified by testing the same compressors on the refrigerator.