Sequence amplitude modulated inverters

This Static Inverter produces a true stepped waveform from a direct current source, which is symmetrical from one half cycle to the next half cycle. Because of its low output impedance and OC half-wave circulating path for current, the Inverter will deliver rectified, non-linear loads and still operate normally (low distortion) and under extremely poor power factor loads. The method used to obtain this type of stepped waveform was originally developed in 1965. With the advent of integrated circuits, the complexity and cost of the design was considerably reduced. Production of the eight steps of the waveform previously required eight separate volt?? age generating sources. Today, through the use of integrated circuits, two or three voltage sources can perform the necessary function of producing eight to twenty-six (or more) steps if desired in a half wave cycle period. Only a fraction of the power (7%) is switched at a high frequency rate as compared with a Pulse Width Modulated technique. The bulk of the power (70%) is generated at the output frequency. The method of inversion discussed here can generate a high quality, high power sine wave voltage that meets most of the desirable character?? istics of a high-quality inverter including low output impedance.