Universal power converter
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.
1. A Buck-Boost Converter, comprising:
an inductive energy-transfer reactance, comprising paralleled capacitive and inductive components connected across a pair of busses, which operates in a full cycle mode with two rower transfers for each cycle;
first and second voltage source power portals, each with two or more ports by which electrical power is input from or output to said portals; and
first and second full-bridge switch arrays,
both connected across said pair of busses,
each connected to a respective ones of said portals, and
each comprising at least one bidirectional conducting and blocking switching device, which can block voltage and conduct current in both directions, for each said port of each said power portal; and
a controller which is connected to operate said bridge switch arrays, with mutually exclusive conduction intervals, to drive current from both of said busses through said reactance in both directions during each cycle.
2. The converter of claim 1 , wherein said bridge arrays are symmetrically connected to said energy-transfer reactance.
3. The converter of claim 1 , further comprising a third switch array, which is connected to said reactance in parallel with said first and second switch arrays.
4. The converter of claim 1 , wherein each said portal is shunted by a capacitor which provides a low-impedance voltage source thereat.
5. The converter of claim 1 , wherein said reactance comprises a transformer.
6. The converter of claim 1 , wherein said reactance is driven at a base frequency which is less than half its resonant frequency.