This invention improves the performance and lowers the cost of DC to AC
inverters and the systems where these inverters are used. The performance
enhancements are most valuable in renewable and distributed energy
applications where high power conversion efficiencies are critical. The
invention allows a variety of DC sources to provide power thru the
inverter to the utility grid without a transformer and at very high power
conversion efficiencies. The enabling technology is a novel inverter
circuit topology where the DC source is connected directly to the
positive bus of the DC to AC converter and where a negative bus is
generated from the positive bus with a flyback converter. The inverter
power topology does include or require a transformer. The AC inverter
output configuration can be either single-phase or three-phase. The AC
inverter output can be either utility interactive or directly supply
loads.