A power supply apparatus includes a control circuit, and first and second power storage connected to a DC link circuit between an inverter and a converter. The control circuit, while the AC power supply is in a normal condition, controls the first power storage to discharge when the control circuit detects that electric power consumption exceeds a threshold, and controls at least one of the first and second power storage to charge when the control circuit detects that the electric power consumption does not exceed the threshold, and while the AC power supply is in an abnormal condition, controls the second power storage to discharge, and controls the first power to discharge when it is detected that the electric power consumption exceeds the threshold.