CONTROLLER AND CONTROL METHOD FOR COMPRESSOR IN REFRIGERATOR

摘要

PROBLEM TO BE SOLVED: To protect an inverter and a compressor by detecting each phase voltage of three-phase power supply lines between the inverter and the compressor and stopping driving of the compressor when a decision is made based on the detection results that a defective connection has occurred where at least one phase is opened. SOLUTION: A control section 50 applies a switching signal to an inverter 20 through an inverter drive section 60 and drives a compressor 30 for a predetermined time. A position sensing section 40 senses the counter electromotive force in each phase of the compressor 30 and determines the rotor position and the r.p.m. A phase voltage sensing section 90 senses the counter electromotive force in each phase and delivers a phase voltage detection signal. When at least one phase is opened, the phase voltage does not appear in that phase and the transistor at the phase voltage sensing section 90 is sustained in off state. When a low signal delivered continuously from the phase voltage sensing section 90, the control section 50 makes a decision that the connection between the inverter 20 and the compressor 30 is opened and stops the compressor 30.