POWER SUPPLY APPARATUS, INVERTER AND AIR CONDITIONER

摘要

PROBLEM TO BE SOLVED: To provide a power supply apparatus which can control an excessive input voltage inputted in an abnormal state of an AC power supply voltage and to provide an inverter and an air conditioner in which the apparatus is used. SOLUTION: A switching operation control means 11 controls operations of switching devices 4a and 3b so as to improve a power factor and set a DC voltage outputted to a load 7 to a predetermined target DC voltage. If a pulse width and a pulse interval of a pulse signal outputted from a voltage polarity detection means 20 in synchronism with an AC power supply 1 and corresponding to the voltage polarity of eh power supply 1 are out of predetermined ranges corresponding to the AC power supply frequency, the control means 11 controls the switching operations to stop. Further, after the operations are stopped, it controls the switching operations to r-start at the zero-cross timing of the AC power supply voltage. With this constitution, an excessive input current corresponding to the abnormal state of the AC power supply voltage can be controlled.