Patent ID: 7964990

Claim:
A power supply unit comprising: a straightforward switch connected in series between a power source and a load, and that supplies or interrupts an electric power output from the power source to the load; a first single phase inverter or rectifier including alternating current (AC) side terminals and direct current (DC) side terminals, connected in parallel with the series connection of the power source and the straightforward switch, and with its AC side terminals connected to the load; a second single phase inverter or rectifier including alternating current (AC) side terminals and direct current (DC) side terminals, connected in series with the power source, and with its AC side terminals connected to the load; a battery connected to the DC side terminals of said first and second single phase inverters or rectifiers; and a DC-DC converter connected between the battery and at least one of said first and second single phase inverters or rectifiers, wherein the first and second single phase inverters or rectifiers generate output voltages different from each other and are connected so that each of their output voltages are applied to the load when the straightforward switch is open.