Patent ID: 7072162

Claim:
A method by which on the output of a dc to ac inverter when used in producing a modified sine wave is clamped to a midpoint level between the voltages used within thereby providing an output waveform that remains consistent and independent of any given load comprising: (a) a dc to dc converter that produces high differential voltages from the input of the said dc to ac inverter; (b) a half bridge configured converter capable of supporting full power using three terminal semiconductor devices and using the said high differential voltages in (a); (c) a pulse width modulator function as used to generate the said high differential voltages outputted from the said dc to dc converter in (a) producing a clock frequency that is a multiple of the output said modified sine wave frequency; (d) a clock generator function that divides down the operating frequency of the said pulse width modulator in (c) to the said output said modified sine wave frequency; (e) a pulse wave shaper function that accepts a single input from the said clock generator in (d) and provides drives for the said three terminal semiconductor devices used within the said half bridge configured converter; (f) a snubber pulse generator function that accepts inputs from the said pulse wave shaper function in (e) and provides drives for two said three terminal semiconductor devices; (g) a transformer having three magnetically coupled windings whereby two of the three windings are driven by the said snubber pulse generator in (f); and (h) a filtering function that accepts its input from one winding of the said transformer in (g) and has its output connected to the input of the said dc to ac inverter.