Bi-directional, transformerless voltage system

Patent metadata

Field	Value
Publication number	US-10270368-B2
Application number	US-201615368384-A
Country	US
Kind code	B2
Filing date	Dec 2, 2016
Priority date	Dec 2, 2016
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

A multi-stage electric voltage converter is disclosed. The converter comprises a voltage source and multiple stages. Each stage of the multiple stages comprises a first and a second and a third switch, and a capacitor, wherein the capacitor is coupled to the voltage source by the first and the second switches and each stage is coupled to a different stage or to an output of the multi-stage electric voltage converter by the third switch so as to allow the capacitor to be charged by the voltage source when the first and the second switches are closed and the third switch is open, and to allow the capacitor to be connected to the output of the multi-stage electric voltage converter when the first and the second switches are open and the third switch is closed.

First claim

What is claimed is:

1. A multi-stage electric voltage converter comprising:
a voltage source; and
multiple stages, wherein each stage of the multiple stages comprises:
a first and a second and a third switch, and
a capacitor, wherein the capacitor is coupled to the voltage source by the first and the second switches and each stage of the multiple stages is coupled to a different stage or to an output of the multi-stage electric voltage converter by the third switch so as to allow the capacitor to be charged by the voltage source when the first and the second switches are closed and the third switch is open, and to allow the capacitor to be disconnected from the voltage source and connected to the output of the multi-stage electric voltage converter to supply a voltage from the capacitor that is disconnected from the voltage source to the output when the first and the second switches are open and the third switch is closed.

2. The multi-stage electric voltage converter of claim 1 , wherein the first, second, and third switches are photoconductive switches.

3. The multi-stage electric voltage converter of claim 1 , further comprising a switch that allows neutral isolation during discharge.

4. The multi-stage electric voltage converter of claim 3 , comprising: a load; and
a second multi-stage electric voltage converter coupled to the load and the multi-stage electric voltage converter, wherein the second multi-stage electric voltage converter has a charge and discharge cycle 180° out of phase with the multi-stage electric voltage converter.

5. The multi-stage electric voltage converter of claim 4 , wherein the multi-stage electric voltage converter includes an input having a same polarity as the second multi-stage electric voltage converter.

6. The multi-stage electric voltage converter of claim 4 , wherein the multi-stage electric voltage converter uses an input having a different polarity from the second multi-stage electric voltage converter.

7. The multi-stage electric voltage converter of claim 6 , further comprising:
a fourth switch coupled with the load and the multi-stage electric voltage converter to provide a neutral reference; and
a fifth switch coupled with the load and the second multi-stage electric voltage converter to provide the neutral reference.

8. The multi-stage electric voltage converter of claim 6 , further comprising:
a first diode coupled with the load and the multi-stage electric voltage converter; and a second diode coupled with the load and the second multi-stage electric voltage converter.

9. The multi-stage electric voltage converter of claim 1 , wherein the output of the multi-stage electric voltage converter is connected to an electrical grid.

10. The multi-stage electric voltage converter of claim 1 , wherein the voltage source is coupled to, or is part of, a renewable energy generation system.

11. The multi-stage electric voltage converter of claim 10 , wherein the renewable energy generation system includes a solar power generation device.

12. The multi-stage electric voltage converter of claim 10 , wherein the renewable energy generation system includes a wind turbine.

13. The multi-stage electric voltage converter of claim 1 , wherein the multiple stages convert voltage from the voltage source to the output of the multi-stage electric voltage converter without using separate DC sources (SDCS).

14. The multi-stage electric voltage converter of claim 1 , wherein the multiple stages convert voltage from the voltage source to the output of the multi-stage electric voltage converter without using an electrical transformer.

15. A bidirectional electric converter, comprising:
an electrical power source;
an output load; and
a cascade configuration of a plurality of stages, wherein each stage of the plurality of stages comprises more than two switches and a capacitor coupled to the switches to transfer power from the electrical power source to the output load, wherein the capacitor of each stage is, in a charging cycle, configured to receive the power from the electrical power source and disconnect from the output load, and in a discharging cycle, configured to disconnect from the electrical power source and transfer the power from the capacitor that is disconnected from the electrical power source to the output load,
wherein positions of the electrical power source and the output load are interchangeable.

16. The bidirectional electric converter of claim 15 , wherein: the electrical power source provides a high voltage; and
a capacitor of one stage of the plurality of stages is connected in series with a capacitor of next stage of the plurality of stages through the switches in the charging cycle and is connected in parallel with the capacitor of the next stage of the plurality of stages through the switches in the discharging cycle such that the plurality of stages deliver a voltage lower than the high voltage to the output load.

17. The bidirectional electric converter of claim 15 , wherein: the electrical power source provides a low current; and
a capacitor of one stage of the plurality of stages is connected in series with a capacitor of next stage of the plurality of stages through the switches in the charging cycle and is connected in parallel with the capacitor of the next stage of the plurality of stages through the switches in the discharging cycle such that the plurality of stages deliver a current higher than the low current to the output load.

18. The bidirectional electric converter of claim 15 , wherein: the electrical power source provides a low voltage; and
a capacitor of one stage of the plurality of stages is connected in parallel with a capacitor of next stage of the plurality of stages through the switches in the charging cycle and is connected in series with the capacitor of the next stage of the plurality of stages through the switches in the discharging cycle such that the plurality of stages deliver a voltage higher than the low voltage to the output load.

19. The bidirectional electric voltage converter of claim 15 , wherein: the electrical power source provides a high current; and
a capacitor of one stage of the plurality of stages is connected in parallel with a capacitor of next stage of the plurality of stages through the switches in the charging cycle and is connected in series with the capacitor of the next stage of the plurality of stages through the switches in the discharging cycle such that the plurality of stages deliver a current lower than the high current to the output load.

20. The bidirectional electric converter of claim 15 , wherein the electric power source provides a direct current (DC) voltage and the output load consumes a direct current (DC) voltage.

21. The bidirectional electric voltage converter of claim 15 , wherein the electric power source provides an alternating current (AC) voltage and the output load consumes a direct current (DC) voltage.

22. The bidirectional electric voltage converter of claim 15 , wherein
the electric power source is at a voltage level of 13.6 kV, and is connected to a utility transmission line; and
the output load is at a voltage level below 240V, and is connected to an energy generation device.

23. A method of providing a voltage conversion by a multi-stage bidirectional electric voltage converter, comprising:
supplying a voltage from a voltage source to one or more stages of the multi-stage bidirectional electric voltage converter,

Assignees

• L Livermore Nat Security Llc

Inventors

• Sampayan Stephen E

Classifications

• H02J3/381

  Dispersed generators · CPC title

• H02M3/07

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H02J9/062

  for AC powered loads · CPC title

• H02M1/12

  Arrangements for reducing harmonics from AC input or output · CPC title

• H02J7/34

  Parallel operation in networks using both storage and other DC sources, e.g. providing buffering (H02J7/14 takes precedence) · CPC title