Patent ID: 8310102

Claim:
A multilevel inverter comprising; a plurality of bridges, each bridge configured to receive a respective portion of an input DC power and convert the respective portion of the input DC power to a respective portion of converted AC power; at least one bridge controller for operating at least one of the plurality of bridges in a square waveform mode; a plurality of transformers, each transformer coupled to one of the respective bridge and configured to increase a voltage level of the respective portion of converted AC power of the respective bridge, wherein each of the plurality of transformers comprises a primary winding coupled to the respective bridge and a secondary winding paired with the primary winding and coupled in series with the other secondary windings to combine the respective increased voltage level portions of the converted AC power; a grid converter electrically coupled to the series connected secondary windings of the plurality of transformers and configured to provide output power for a power grid; and a grid controller configured to control operation of the grid converter, wherein the grid converter comprises an AC to AC converter and the grid controller is configured for providing control signals to control the frequency of the output power.