Power circuit, and computer-readable recording medium storing a control program for power circuits

Abstract

When an abnormality occurs in a refrigeration cycle, the inverter motor provided in the air conditioner is stopped reliably and contacts of the main relay are prevented from degradation and fusion. A power circuitof the air conditioner includes a rectifier circuit RC, a capacitor C (smoothing unit), a main relayprovided on a current path between the rectifier circuit RC and the capacitor C, an inverter circuit, a microcomputer, and a delay circuit. The microcomputerhas an inverter circuit control unit, a main relay opening/closing control unit, a waveform forced cut-off unit, and a cut-off signal output unit. Where a high-pressure switch(abnormality detection unit) detects a high-pressure abnormality and outputs a high-pressure abnormality signal to the waveform forced cut-off unitwhen the main relayis in a closed state, the waveform forced cut-off unitelectrically cuts off the inverter circuit control unit, and the cut-off signal output unitoutputs a cut-off signal, which sets the main relayto the open state, to the main relayvia the delay circuit