Methods and systems for transforming
electric power between two or more portals. Any or all portals can be DC,
single phase AC, or multi-phase AC. Conversion is accomplished by a plurality of bi-directional conducting and blocking
semiconductor switches which alternately connect an
inductor and parallel
capacitor between said portals, such that energy is transferred into the
inductor from one or more input portals and / or phases, then the energy is transferred out of the
inductor to one or more output portals and / or phases, with said parallel
capacitor facilitating “soft” turn-off, and with any excess inductor energy being returned back to the input. Soft turn-on and
reverse recovery is also facilitated. Said bi-directional switches allow for two power transfers per inductor /
capacitor cycle, thereby maximizing inductor / capacitor utilization as well as providing for optimum converter operation with
high input / output
voltage ratios. Control means coordinate the switches to accomplish the desired power transfers.