Patent ID: 8036004

Claim:
An uninterruptible power supply comprising: an isolation transformer having dual primary windings and a secondary winding to supply an output voltage; a first winding of the dual primary windings coupled to an inverter circuit that receives an alternating current input voltage; and a second winding of the dual primary windings coupled to a bypass circuit that receives a bypass voltage, wherein voltage is applied to the second winding upon failure of the inverter circuit to generate the output voltage without interruption, wherein the inverter circuit includes a compensation circuit to provide a compensation voltage that maintains the output voltage at an approximately constant level by using feedback from a load current into the first winding of the duel primary windings of the isolation transformer, wherein the compensation circuit includes a voltage compensator to generate the compensation voltage based on the load current into the first winding of the duel primary windings of the isolation transformer, wherein said compensation circuit includes a current transformer, wherein said current transformer is directly connected to the output input of the first winding and is also directly connected to the voltage compensator, wherein the voltage compensator is connected to an inverter located within the inverter circuit.