Power transfer devices, methods, and systems with crowbar switch shunting energy-transfer reactance
The present application discloses methods, circuits and systems for power conversion, using a universal multiport architecture. When a transient appears on the power input (which can be, for example, polyphase AC), the input and output switches are opened, and a crowbar switch shunts the inductance which is used for energy transfer. This prevents this inductance from creating an overvoltage when it is disconnected from outside lines.
1. A Buck-Boost Converter, comprising:
an energy-transfer reactance comprising a parallel combination of an inductor with a capacitor;
first and second power portals, each with two or more ports by which electrical power is input from or output to said portals;
first and second bridge switch arrays interposed between said reactance and respective ones of said portals, and each comprising one bidirectional switching device for each said port of each said power portal, wherein said bridge arrays are full bridge arrays and are symmetrically connected to said energy-transfer reactance; and
a link switch, connected across said reactance in a crowbar configuration which includes a resistor, to dissipate energy stored in said reactance when said link switch is on, and when said parallel combination of said inductor and said capacitor is isolated from said first and second power portals when all of said bidirectional switching devices in the first and second bridge switch arrays are turned off.
2. 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.
3. The converter of claim 1 , wherein each said portal is shunted by a capacitor which provides a low-impedance voltage source thereat.
4. The converter of claim 1 , wherein said reactance comprises a transformer.
5. The converter of claim 1 , wherein said reactance is driven at a base frequency which is less than half its resonant frequency.
6. A Buck-Boost Converter, comprising:
an energy-transfer reactance comprising a parallel combination of an inductor with a capacitor;
a first bridge switch array comprising at least two bidirectional switching devices which are jointly connected to operatively connect at least one terminal of said reactance to a power input, with reversible polarity of connection;
a second bridge switch array comprising at least two bidirectional switching devices which are jointly connected to operatively connect at least one terminal of said reactance to a power output, with reversible polarity of connection, wherein said first and second bridge switch arrays are full bridge arrays and are symmetrically connected to said energy-transfer reactance;
a link switch, connected across said reactance in a crowbar configuration which includes a resistor, to dissipate energy stored in said reactance when said link switch is on, and when said parallel combination of said inductor and said capacitor is isolated from said power input and said power output when all of said bidirectional switching devices in the first and second bridge switch arrays are turned off; and
wherein said first switch array drives said reactance with a nonsinusoidal voltage waveform.
7. The converter of claim 6 , further comprising a third switch array, which is connected to said reactance in parallel with said first and second switch arrays.
8. The converter of claim 6 , wherein said input is shunted by a capacitor which provides a low-impedance voltage source thereat.
9. The converter of claim 6 , wherein said input and output are both shunted by respective capacitors which provide low-impedance voltage sources thereat.
10. The converter of claim 6 , wherein said reactance comprises a transformer.
11. The converter of claim 6 , wherein said reactance is driven at a base frequency which is less than half its resonant frequency.
12. A Full-Bridge Buck-Boost Converter, comprising: first and second full bridge switch arrays, each comprising at least four bidirectional switching devices;
a substantially parallel inductor-capacitor combination symmetrically connected to be driven separately by either said switch array; and
a link switch, connected across said inductor-capacitor combination in a crowbar configuration which includes a resistor, to dissipate energy stored in said reactance when said link switch is on, and when said parallel combination of said inductor and said capacitor is isolated from a power input and a power output when all of said bidirectional switching devices in the first and second full bridge switch arrays are turned off;
one of said switch arrays being operatively connected to said power input, and the other thereof being operatively connected to supply said power output.
13. The converter of claim 12 , wherein said power input is shunted by a capacitor which provides a low-impedance voltage source thereat.