Hybrid Power Converter for Renewable Energy Power Plant

• US 20150295513A1
• Filed: 04/14/2014
• Published: 10/15/2015
• Est. Priority Date: 04/14/2014
• Status: Active Grant

• Current Assignee: TMEIC Corp. Americas
• Original Assignee: Tmeic Corporation (Toshiba Corporation)
• Inventors: BIXEL, Paul S.
• Granted Patent: US 9,923,487 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02P 90/50 Energy storage in industry with an added climate change mitigation effect

Abstract

A hybrid power converter system that comprises a first power bus connected to a DC power source, a second power bus connected to an AC load, and a third power bus connected to an energy storage device. One or more power converters are connected to the first power bus in parallel and are connected with the second and third power buses, each by a switch. The system includes a first switch for connecting or disconnecting a power converter to or from the second power bus and a second switch for connecting or disconnecting the power converter to or from the third power bus, to switch the source of power being provided to the AC load either from the DC power source or the energy storage device. With additional power converters connected into the system in a similar manner, several combinations of power supply are possible.

Claims

1. A hybrid power converter system comprising:

a DC power source;

a DC bus;

a three phase power converter configured for converting DC power to AC power;

wherein the power converter is operably connected with a first power bus comprising the DC power source and the DC bus;

wherein the power converter is operably connected by a first switch S1 with a second power bus comprising a transformer, and is operably connected by a second switch S2 with a third power bus comprising an energy storage device, provided that, during use, no more than one of switch S1 or S2 is open;

such that, during use, when switch S1 is open and switch S2 is closed, power is capable of being delivered from the DC power source to the transformer, and when switch S2 is open and switch S1 is closed, power is capable of being delivered from the DC power source to the energy storage device.

2. The system of claim 1, wherein the DC power source is a device for converting a renewable energy source into DC power.

3. The system of claim 2, wherein the device for converting a renewable energy source into DC power is one or more photovoltaic modules.

4. The system of claim 3, wherein the device for converting a renewable energy source into DC power is a photovoltaic (PV) array of photovoltaic modules.

5. The system of claim 4, wherein the PV array comprises photovoltaic modules connected in series and parallel relative to one another.

6. The system of claim 1, further comprising a controller operably configured for sequencing switches S1 and S2 during use according to an amount of power available from the DC power source.

14. The system of claim 1, wherein the DC power source comprises one or more photovoltaic modules at a solar energy site, one or more turbines at a wind energy site, or one or more turbines at a tidal energy site.

7. A hybrid power converter system comprising:

a first power bus comprising one or more photovoltaic modules operably connected with a DC bus;

a first and a second three phase power converter, each configured for converting DC power to AC power, and operably connected in parallel with the first power bus;

a second power bus comprising one or more transformer and operably connected to the first and second three phase power converters, each by a switch;

a third power bus comprising one or more energy storage device and operably connected to the first and second three phase power converters, each by a switch;

provided that, during use, no more than one switch between the first power converter and the second or third power bus is open, and no more than one switch between the second power converter and the second or third power bus is open;

such that, during use, when a switch between the second power bus and the first or second power converters is open, power is capable of being delivered from the photovoltaic modules through the second power bus to an AC load, and when a switch between the third power bus and the first or second power converters is open, power is capable of being delivered from the energy storage device through the third power bus to an AC load to supplement or replace power from the photovoltaic modules.

8. The system of claim 7, wherein the one or more photovoltaic modules comprises a photovoltaic (PV) array comprising a plurality of PV modules connected in series and in parallel relative to one another.

9. The system of claim 7, further comprising a controller operably configured for sequencing the switches during use according to an amount of power available from the photovoltaic modules.

10. The system of claim 7, further comprising:

one or more additional power converters operably connected to the first power bus in parallel with the first and second power converters;

wherein each of the one or more additional power converters is operably connected to the second power bus by a switch and to the third power bus by a switch;

provided that, during use, no more than one switch between the additional power converter and the second or third power bus is open, and no more than one switch between the additional power converter and the second or third power bus is open;

wherein during use, power is capable of being delivered to an AC load;

from the photovoltaic modules through the second power bus and any one or more of the first, second, or additional power converters when a switch between the first, second, or additional power converter and the transformer is open; and

/or

from the energy storage device through the third power bus and any one or more of the first, second, or additional power converters when a switch between the first, second, or additional power converter and the energy storage device is open.

11. The system of claim 10, further comprising a controller operably configured for sequencing the switches during use according to an amount of power available from the photovoltaic modules.

12. The system of claim 10 comprising:

a first and a second three phase power converter and two additional power converters for a total of four power converters;

wherein each of the four power converters is operably connected to the first power bus in parallel with one another;

wherein the four power converters each have an identical rated power (PU);

such that, during use, the system is capable of a minimum AC output, a maximum AC output, and an energy storage power as follows;

a) with the switch of each power converter open to the second power bus and no switch open between any of the power converters and the third power bus, the system is capable of a minimum AC output of 0 PU, a maximum AC output of 4 PU, and an energy storage power of 0 PU;

b) with the switch of three power converters open to the second power bus and the switch of one power converter open to the third power bus, the system is capable of a minimum AC output of 1 PU, a maximum AC output of 3 PU, and an energy storage power of +/−

1 PU;

c) with the switch of two power converters open to the second power bus and the switch of two power converters open to the third power bus, the system is capable of a minimum AC output of 2 PU, a maximum AC output of 2 PU, and an energy storage power of +/−

2 PU;

d) with the switch of one power converter open to the second power bus and the switch of three power converters open to the third power bus, the system is capable of a minimum AC output of 1 PU, a maximum AC output of 1 PU, and an energy storage power of −

3 PU to +1 PU;

e) with no switch open between any of the power converters and the second power bus and the switch of each power converter open to the third power bus, the system is capable of a minimum AC output of 0 PU, a maximum AC output of 0 PU, and an energy storage power of −

4 PU to 0 PU.

13. The system of claim 12, further comprising a controller operably configured for sequencing the switches during use according to an amount of power available from the photovoltaic modules.

15. A method of managing energy provided to an AC load comprising:

monitoring an amount of power available from a DC power source connected with a first power bus to identify a change or potential change in power output;

in response to identifying a reduced amount of power from the DC power source;

closing a switch between a power converter, which power converter is connected with the first power bus, and a second power bus comprising a transformer; and

opening a switch between that power converter and a third power bus comprising one or more energy storage devices; and

allowing power to flow to an AC load from the energy storage devices.

16. The method of claim 15, wherein the first power bus is part of a hybrid power converter system further comprising:

a DC power source;

a DC bus;

a three phase power converter configured for converting DC power to AC power;

wherein the power converter is operably connected with the first power bus which comprises the DC power source and the DC bus;

wherein the power converter is operably connected by a first switch S1 with a second power bus comprising a transformer, and is operably connected by a second switch S2 with a third power bus comprising an energy storage device, provided that, during use, no more than one of switch S1 or S2 is open;

such that, during use, when switch S1 is open and switch S2 is closed, power is capable of being delivered from the DC power source to the transformer, and when switch S2 is open and switch S1 is closed, power is capable of being delivered from the DC power source to the energy storage device.

17. The method of claim 15, wherein the first power bus comprises one or more photovoltaic modules operably connected with a DC bus, and wherein the first power bus is part of a hybrid power converter system further comprising:

a first and a second three phase power converter, each configured for converting DC power to AC power, and operably connected in parallel with the first power bus;

a second power bus comprising one or more transformer and operably connected to the first and second three phase power converters, each by a switch;

a third power bus comprising one or more energy storage device and operably connected to the first and second three phase power converters, each by a switch;

provided that, during use, no more than one switch between the first power converter and the second or third power bus is open, and no more than one switch between the second power converter and the second or third power bus is open;

such that, during use, when a switch between the second power bus and the first or second power converters is open, power is capable of being delivered from the photovoltaic modules through the second power bus to an AC load, and when a switch between the third power bus and the first or second power converters is open, power is capable of being delivered from the energy storage device through the third power bus to an AC load to supplement or replace power from the photovoltaic modules.

18. The method of claim 17, wherein the hybrid power converter system further comprises:

a first and a second three phase power converter and two additional power converters for a total of four power converters;

wherein each of the four power converters is operably connected to the first power bus in parallel with one another;

wherein the four power converters each have an identical rated power (PU);

such that, during use, the system is capable of a minimum AC output, a maximum AC output, and an energy storage power as follows;

a) with the switch of each power converter open to the second power bus and no switch open between any of the power converters and the third power bus, the system is capable of a minimum AC output of 0 PU, a maximum AC output of 4 PU, and an energy storage power of 0 PU;

b) with the switch of three power converters open to the second power bus and the switch of one power converter open to the third power bus, the system is capable of a minimum AC output of 1 PU, a maximum AC output of 3 PU, and an energy storage power of +/−

1 PU;

c) with the switch of two power converters open to the second power bus and the switch of two power converters open to the third power bus, the system is capable of a minimum AC output of 2 PU, a maximum AC output of 2 PU, and an energy storage power of +/−

2 PU;

d) with the switch of one power converter open to the second power bus and the switch of three power converters open to the third power bus, the system is capable of a minimum AC output of 1 PU, a maximum AC output of 1 PU, and an energy storage power of −

3 PU to +1 PU;

e) with no switch open between any of the power converters and the second power bus and the switch of each power converter open to the third power bus, the system is capable of a minimum AC output of 0 PU, a maximum AC output of 0 PU, and an energy storage power of −

4 PU to 0 PU.

19. The method of claim 15, wherein the method comprises opening or closing the switches using a computer processor.

20. The method of claim 15, wherein the monitoring comprises one or more of forecasting weather in a vicinity of the DC power source, measuring power output of the DC power source, or a combination of both.