Patent ID: 8482154

Claim:
An uninterruptible power supply apparatus, comprising: a PWM converter that generates a DC voltage based on a first AC voltage and outputs the DC voltage between first and second nodes; a first capacitor connected between said first and second nodes; a PWM inverter that receives said DC voltage and generates a second AC voltage; a common mode reactor having first and second coils, one terminal of the first coil being connected to a positive electrode of a battery, and one terminal of the second coil being connected to a negative electrode of said battery; and a bidirectional chopper circuit, connected to said first and second nodes and connected to the other terminals of said first and second coils, that supplies DC power from said first capacitor to said battery through said common mode reactor when said first AC voltage is supplied, and supplies DC power from said battery to said first capacitor through said common mode reactor when a supply of said first AC voltage is stopped, said bidirectional chopper circuit including first and second switching elements connected in series between said first and second nodes, and a normal mode reactor having a third coil connected between a third node between said first and second switching elements and the other terminal of said first coil, and a fourth coil connected to said second switching element and the other terminal of said second coil.