Universal power conversion methods
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 method for operating a Buck-Boost Converter, comprising the actions of:
(a) operating a first bridge switch array, comprising bidirectional conducting and blocking switching devices, to operatively connect at least one terminal of an energy-transfer reactance to a power input, with polarity which reverses at different times, the energy-transfer reactance comprising paralleled capacitive and inductive components, which operate in a full cycle mode to output two power transfers for each cycle;
(b) operating a second bridge switch array, comprising bidirectional conducting and blocking switching devices, to operatively connect at least one terminal of said energy-transfer reactance to a power output, with polarity which reverses at different times, the energy-transfer reactance comprising paralleled capacitive and inductive components, which operate in a full cycle mode to output two power transfers for each cycle;
wherein said actions (a) and (b) are not performed simultaneously; and
wherein each bidirectional conducting and blocking switching device is operated to block voltage and conduct current in both directions at mutually exclusive conduction intervals.
2. The method of claim 1 , wherein said bridge arrays are symmetrically connected to said energy-transfer reactance.
3. The method of claim 1 , wherein said energy-transfer reactance comprises a transformer.
4. The method of claim 1 , further comprising the action of:
connecting a third bridge switch array to said energy-transfer reactance in parallel with the first and second switch arrays.
5. The method of claim 1 , wherein said reactance is driven at a base frequency which is less than its resonant frequency.
6. A method for operating a Buck-Boost Converter, comprising the actions of:
operating a first bridge switch array, comprising bidirectional conducting and blocking switching devices, which can block voltage and conduct current in both directions, operated by a controller to operatively connect at least one terminal of an energy-transfer reactance comprised of a substantially parallel inductor-capacitor combination to a power input, with polarity which reverses at different times;
wherein said first switch array is operatively connected to a power input, and is operated to drive power into said inductor-capacitor combination with a non-sinusoidal waveform;
operating a second one of said switch arrays to extract power from said inductor-capacitor combination to an output; and
controlling at least one of said switch arrays to drive said inductor-capacitor combination with alternating current in a full cycle mode to generate two power transfers each cycle.
7. The method of claim 6 , wherein said bridge arrays are symmetrically connected to said energy-transfer reactance.
8. The method of claim 6 , wherein said energy-transfer reactance comprises a transformer.
9. The method of claim 6 , further comprising the step of:
connecting a third bridge switch array to said energy-transfer reactance in parallel with the first and second switch arrays.
10. The method of claim 6 , wherein said energy-transfer reactance is driven at a base frequency which is less than its resonant frequency.
11. A method for operating a power converter, comprising the actions of:
driving an energy-transfer reactance with a full AC waveform, at a base frequency which is less than the resonant frequency of said reactance;
coupling power into said energy-transfer reactance, on each cycle thereof, with two different drive phases, respectively supplied from two different legs of a polyphase power source;
coupling power out of said energy-transfer reactance, on each cycle thereof, with two different connection phases, respectively driving two different legs of a polyphase power output;
controlling from a coupled controller a first and second full bridge switch array, each comprising at least four bidirectional conducting and blocking switching devices which can block voltage and conduct current in both directions, to produce mutually exclusive conduction intervals, said arrays respectively interposed between the energy-transfer reactance and the polyphase power source and the polyphase power output, and operated to couple the legs of the polyphase power source and the polyphase power output to the energy-transfer reactance; and
generating from the energy-transfer reactance in a full cycle mode a power output of two power transfers for each cycle.
12. The method of claim 11 , wherein said bridge switch arrays are symmetrically connected to said energy-transfer reactance.
13. The method of claim 11 , wherein said energy-transfer reactance comprises a transformer.
14. The method of claim 11 , wherein said energy-transfer reactance comprises a parallel combination of an inductor with a capacitor.
15. The method of claim 11 , further comprising the step of:
connecting a third bridge switch array to said energy-transfer reactance in parallel with the first and second switch arrays.