Patent ID: 7432617

Claim:
An uninterruptible power system for inputting an AC power, converting the AC power into a desired power using a multi-coil transformer, supplying the desired power to a load, and upon occurrence of an AC failure, converting a DC power from an energy accumulator into the desired power and supplying the desired power to the load, wherein the DC power from the energy accumulator is passed through two serially connected boosters, and thereafter the power is converted into the desired power to be supplied to the load, wherein a first booster of the two serially connected boosters, which is nearer to the energy accumulator, is coupled, in a power normal state, to receive charging energy from a secondary winding side of the multi-coil transformer and to charge the energy accumulator using the same; and wherein the first booster is coupled, in a power failure state, to supply backup energy from the energy accumulator to a primary winding side of the multi-coil transformer.