Patent ID: 7064969

Claim:
A DC-to-AC power converter apparatus for converting power from a mono-polar DC source to an AC load where one side of said DC source is connected to the grounded, zero-voltage or neutral point of said AC load voltage, a point that is typically but not necessarily grounded with respect to earth and where said mono-polar DC source is connected directly across one of two DC buses and where a second DC bus of opposite polarity with respect to the first DC bus is created by an inverting DC-to-DC power converter where the mono-polar DC source is connected to the DC-to-DC converter input and the output of the DC-to-DC converter is connected to the second DC bus and where two semiconductor switching devices are connected in series across the two DC buses with the common point of the two semiconductor switching devices connecting through a filter inductor to an AC load, in a circuit arrangement typically know as a half-bridge, and where the DC-to-AC power conversion of one polarity of the AC waveform is accomplished with one power conversion stage and where the DC-to-AC power conversion of the opposite polarity of the AC waveform is accomplished with two power conversion stages.