Static inverter with controlled core saturation

A static inverter comprising:

• a. input terminals for connection to a source of d.c. potentials,
• b. a pair of semiconductor power switching devices, each semiconductor device having a pair of input electrodes and an output electrode,
• c. a transformer having
• 1. a core of substantially linear magnetic material having a closed magnetic path of approximately uniform cross-section with a pair of apertures in the core, each aperture partitioning the magnetic cross-sections in a localized region into two branches between which the flux may be steered with a magnetomotive force,
• 2. a pair of primary power windings encircling the full core cross-section, each coupled between an output electrode of one of said semiconductor devices and said source terminals for generating an alternating flux in said core as said devices are switched,
• 3. a secondary power winding encircling the full core cross-section to derive an alternating voltage output,
• d. means for causing said power switching devices to conduct in alternation comprising:
• 1. a first pair of regenerative feedback windings, one winding (R.sub.1) passing through the first aperture, the other winding (R.sub.2) passing through the second aperture, and each winding (R.sub.1 and R.sub.2) encircling a first branch,
• 2. a second pair of degenerative feedback windings, one winding (D.sub.1) passing through the first aperture, and the other winding (D.sub.2) passing through the second aperture and each winding (D.sub.1 and D.sub.2) encircling a second branch,
• the first regenerative (R.sub.1) and the first degenerative (D.sub.1) winding connected in series opposition between the input electrodes of the first semiconductor device and the second regenerative winding (R.sub.2) and the second degenerative winding (D.sub.2) being connected in series opposition between the input electrodes of the second semiconductor device, and
• 3. means to cause a differential magnetization rate higher in each first branch than in the local second branch to cause said first branch to saturate first, said saturation removing the regenerative feedback and applying unopposed degenerative feedback to said input electrodes to cause a reverse input bias in advance of full core saturation thus avoiding stresses on said switching device.