An Uninterruptible Power Supply system, the UPS system comprising: an input configured to be coupled to an AC source and to receive input AC power from the AC source; an output configured to provide output AC power to a load; a converter coupled to the input and configured to convert the input power into DC power having a positive DC voltage level and a negative DC voltage level; a plurality of DC busses (106, 108, 110) coupled to the converter and configured to receive the DC power from the converter, the plurality of DC busses (106, 108, 110) including a positive DC bus configured to maintain the positive DC voltage level, a mid-point DC bus, and a negative DC bus configured to maintain the negative DC voltage level; a 3-level inverter coupled to the plurality of DC busses (106, 108, 110) and configured to convert the DC power from the plurality of DC busses (106, 108, 110) into the output AC power and provide the output AC power to the output; and a controller configured to monitor the positive DC voltage level and the negative DC voltage level, identify an imbalance between the positive DC voltage level and the negative DC voltage level, and selectively control, based on the imbalance, the 3-level inverter to operate in a 2-level mode of operation and a 3-level mode of operation to transfer energy between the positive DC bus and the negative DC bus, wherein in operating the 3-level inverter in the 2-level mode of operation, the controller is further configured to operate the 3-level inverter to alternately couple the output to the positive DC bus and the negative DC bus to alternately provide a positive DC pulse and a negative DC pulse, respectively, to the output, wherein in operating the 3-level inverter in the 3-level mode of operation, the controller is further configured to operate the 3-level inverter to alternately couple the output to the mid-point DC bus and one of the positive DC bus and the negative DC bus, and wherein in selectively controlling the 3-level inverter to operate in the 2-level mode of operation and the 3-level mode of operation, the controller is further configured to operate the 3-level inverter, during a half-period of a line cycle, in the 2-level mode of operation to transfer energy between the positive DC bus and the negative DC bus. an input configured to be coupled to an AC source and to receive input AC power from the AC source; an output configured to provide output AC power to a load; a converter coupled to the input and configured to convert the input power into DC power having a positive DC voltage level and a negative DC voltage level; a plurality of DC busses (106, 108, 110) coupled to the converter and configured to receive the DC power from the converter, the plurality of DC busses (106, 108, 110) including a positive DC bus configured to maintain the positive DC voltage level, a mid-point DC bus, and a negative DC bus configured to maintain the negative DC voltage level; a 3-level inverter coupled to the plurality of DC busses (106, 108, 110) and configured to convert the DC power from the plurality of DC busses (106, 108, 110) into the output AC power and provide the output AC power to the output; and a controller configured to monitor the positive DC voltage level and the negative DC voltage level, identify an imbalance between the positive DC voltage level and the negative DC voltage level, and selectively control, based on the imbalance, the 3-level inverter to operate in a 2-level mode of operation and a 3-level mode of operation to transfer energy between the positive DC bus and the negative DC bus, wherein in operating the 3-level inverter in the 2-level mode of operation, the controller is further configured to operate the 3-level inverter to alternately couple the output to the positive DC bus and the negative DC bus to alternately provide a positive DC pulse and a negative DC pulse, respectively, to the output, wherein in operating the 3-level inverter in the 3-level mode of operation, the controller is further configured to operate the 3-level inverter to alternately couple the output to the mid-point DC bus and one of the positive DC bus and the negative DC bus, and wherein in selectively controlling the 3-level inverter to operate in the 2-level mode of operation and the 3-level mode of operation, the controller is further configured to operate the 3-level inverter, during a half-period of a line cycle, in the 2-level mode of operation to transfer energy between the positive DC bus and the negative DC bus. wherein in operating the 3-level inverter in the 2-level mode of operation, the controller is further configured to operate the 3-level inverter to alternately couple the output to the positive DC bus and the negative DC bus to alternately provide a positive DC pulse and a negative DC pulse, respectively, to the output, wherein in operating the 3-level inverter in the 3-level mode of operation, the controller is further configured to operate the 3-level inverter to alternately couple the output to the mid-point DC bus and one of the positive DC bus and the negative DC bus, and wherein in selectively controlling the 3-level inverter to operate in the 2-level mode of operation and the 3-level mode of operation, the controller is further configured to operate the 3-level inverter, during a half-period of a line cycle, in the 2-level mode of operation to transfer energy between the positive DC bus and the negative DC bus.