POWER CONVERSION SYSTEM AND METHOD

• US 20150035284A1
• Filed: 08/01/2014
• Published: 02/05/2015
• Est. Priority Date: 08/02/2013
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: YANG, Wenqiang, SHE, Hongwu, NAIK, Rajendra, IYER, Shivkumar Venkatraman
• Granted Patent: US 9,263,962 B2
• Time in Patent Office: Days
• US Class Current: 290/55
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/0074 Plural converter units whose inputs are connected in series
• CPC Class Codes: H02M 1/0077 Plural converter units whose outputs are connected in series
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 5/42 by static converters
• CPC Class Codes: H02M 7/5395 by pulse-width modulation
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin

Abstract

An exemplary power conversion system includes a first power conversion module, a second power conversion module, and a controller. The first power conversion module includes a first source side converter, a first load side converter, and a first DC link coupled between the first source side converter and the second load side converter. The second power conversion module includes a second source side converter, a second load side converter, and a second DC link coupled between the second source side converter and the second load side converter. The controller is configured to generate a number of switching signals according to a circuit structure of the power source module or a circuit structure of the load module. The switching signals are provided to the first power conversion module and the second power conversion module to balance a first DC link voltage and a second DC link voltage.

Claims

1. A power conversion system, comprising:

a first power conversion module coupled with a power source module via one or more first input terminals, wherein the first power conversion module is configured to convert a first input power at the one or more first input terminals to a first output power at one or more first output terminals for providing to a load module, the first power conversion module comprising a first source side converter, a first load side converter, and a first DC link coupled between the first source side converter and the first load side converter;

a second power conversion module coupled with the power source module via one or more second input terminals, wherein the second power conversion module is configured to convert a second input power at the one or more second input terminals to a second output power at one or more second output terminals for providing to the load module, the second power conversion module comprising a second source side converter, a second load side converter, and a second DC link coupled between the second source side converter and the second load side converter; and

a controller in electrical communication with the first power conversion module and the second power conversion module, wherein the controller is configured to generate a number of switching signals according to a circuit structure of the power source module or a circuit structure of the load module, wherein the switching signals are provided to the first power conversion module and the second power conversion module to balance a first DC link voltage at the first DC link and a second DC link voltage at the second DC link.

2. The power conversion system of claim 1, wherein:

the load module comprises an open-winding transformer configured to provide the first output power and the second output power to a power grid, wherein the open-winding transformer comprises an open-winding primary side and a secondary side, the open-winding primary side is coupled between the one or more first output terminals and the one or more second output terminals; and

the switching signals comprise a number of first and second load side switching signals for providing to the first load side converter and the second load side converter respectively, wherein the first and second load side switching signals are generated according to one or more first load side voltage references and one or more second load side voltage references respectively, wherein each first load side voltage reference and each corresponding second load side voltage reference have the same value with a reverse phase.

3. The power conversion system of claim 1, wherein:

the first and second input power are commonly supplied from a non-open-winding generator; and

the switching signals comprise a number of first and second source side switching signals for providing to the first source side converter and the second source side converter respectively, wherein the first and second source side switching signals are generated according to one or more first source side current references and one or more second source side current references respectively, for receiving the same amount of first input active power and second input active power to balance the first DC link voltage and the second DC link voltage.

4. The power conversion system of claim 1, wherein:

the first input power is supplied from a first power source of the power source module, the second input power is supplied from a second power source of the power source module, and the first power source and the second power source are separately arranged from each other; and

the switching signals comprise a number of first and second source side switching signals for providing to the first source side converter and the second source side converter respectively, wherein the first and second source side switching signals are generated according to a first source side power reference and a second source side power reference respectively, for receiving the same amount of first input power and second input power to balance the first DC link voltage and the second DC link voltage.

5. The power conversion system of claim 1, wherein:

the first input power and the second input power are commonly supplied from an open-winding generator; and

the switching signals comprise a number of first and second source side switching signals for providing to the first source side converter and the second source side converter respectively, wherein the first and second source side switching signals are generated according to one or more first source side voltage references and one or more second source side voltage references respectively, for receiving the same amount of first input active power and second input active power to balance the first DC link voltage and the second DC link voltage, wherein a source side dynamic coefficient is set between each of the one or more first source side voltage references and each of the corresponding one or more second source side voltage references.

6. The power conversion system of claim 5, wherein the source side dynamic coefficient is calculated based at least in part on a ratio or a difference between a first feedback DC link voltage at the first DC link and a second feedback DC link voltage at the second DC link.

7. The power conversion system of claim 1, wherein:

the power source module comprises an open-winding transformer configured to receive the first input power and the second input power from a power grid, the open-winding transformer comprises a primary side and an open-winding secondary side, wherein the open-winding secondary side is coupled between the one or more first input terminals and the one or more second input terminals; and

the switching signals comprise a number of first and second source side signals for providing to the first source side converter and the second source side converter respectively, wherein the first and second source side signals are generated according to one or more first source side voltage references and one or more second source side voltage references respectively, wherein each of the first source side voltage references and each of the corresponding second source side voltage references have the same value with a reverse phase.

8. The power conversion system of claim 1, wherein:

the first output power and the second output power are commonly provided to a DC load; and

the switching signals comprise a number of first and second load side switching signals for providing to the first load side converter and the second load side converter respectively, wherein the first and second load side switching signals are generated according to a first load side power reference and a second load side power reference to provide the same amount of first output power and second output power, to balance the first DC link voltage and the second DC link voltage.

9. The power conversion system of claim 1, wherein:

the first output power and the second output power are commonly provided to an open-winding motor; and

the switching signals comprise a number of first and second load side switching signals generated according to one or more first load side voltage references and one or more second load side voltage references respectively, for providing the same amount of first output active power and second output active power to the motor to balance the first DC voltage and the second DC voltage, wherein a load side dynamic coefficient is set between each of the one or more first source side voltage references and each of the corresponding one or more second source side voltage references.

10. The power conversion system of claim 9, wherein the load side dynamic coefficient is calculated based at least in part on a ratio or a difference between a first feedback DC link voltage at the first DC link and a second feedback DC link voltage at the second DC link.

11. The power conversion system of claim 1, wherein:

the load module comprises a transformer for providing an output power obtained from the first output power and the second output power to a power grid; and

the switching signals comprise a number of first load side switching signals generated by comparing one or more first load side voltage references with one or more first carrier waves and a number of second load side switching signals generated by comparing one or more second load side voltage references with one or more second carrier waves, wherein a phase shift is set between each first carrier wave and each corresponding second carrier wave.

12. A method for controlling a power conversion system, the method comprising:

generating a number of switching signals according to a circuit structure of a power source module or a circuit structure of a load module; and

providing the number of switching signals to a first power conversion module and a second power conversion module to balance a first DC link voltage at a first DC link and a second DC link voltage at a second DC link.

13. The method of claim 12, comprising generating a number of first and second load side switching signals according to one or more first load side voltage references and one or more second load side voltage references when the load module comprises an open-winding transformer, wherein each of the first load side voltage references and each of the corresponding second load side voltage references have the same value with a reverse phase.

14. The method of claim 12, comprising generating a number of source side switching signals according to one or more first source side current references and one or more second source side current references to receive the same amount of first input active power and second input active power when the power source module is a non-open-winding generator.

15. The method of claim 12, comprising generating a number of source side switching signals according to one or more first source side voltage references and one or more second source side voltage references to receive the same amount of first input power and second input power when the power source module is an open-winding generator, wherein a source side dynamic coefficient is set between each of the one or more first source side voltage references and each of the corresponding second source side voltage references.

16. The method of claim 15, comprising calculating the source side dynamic coefficient based at least in part on a ratio or a difference between a first feedback DC link voltage at the first DC link and a second feedback DC link voltage at the second DC link.

17. The method of claim 12, comprising generating a number of first and second source side switching signals according to one or more first source side voltage references and one or more second source side voltage references when the power source module comprises an open-winding transformer, wherein each of the first source side voltage references and each of the corresponding second source side voltage references have the same value with a reverse phase.

18. The method of claim 12, comprising generating a number of load side switching signals according to one or more first load side current references and one or more second load side current references to provide the same amount of first output active power and second output active power when the load module is a non-open-winding motor.

19. The method of claim 12, comprising generating a number of load side switching signals according to one or more first load side voltage references and one or more second load side voltage references to provide the same amount of first output active power and second output active power when the load module is an open-winding motor, wherein a load side dynamic coefficient is set between each of the one or more first load side voltage references and each of the corresponding second load side voltage references.

20. A wind power conversion system, comprising:

a wind generator for providing a first input power at one or more first input terminals and a second input power at one or more second input terminals;

a first power conversion module coupled with the wind generator via the one or more first input terminals, wherein the first power conversion module is configured to convert the first input power to a first output power at one or more first output terminals for providing to a power grid, the first power conversion module comprising a first rectifier, a first inverter, and a first DC link coupled between the first rectifier and the first inverter;

a second power conversion module coupled with the wind generator via the one or more second input terminals, wherein the second power conversion module is configured to convert the second input power to a second output power at one or more second output terminals for providing to a load module, the second power conversion module comprising a second rectifier, a second inverter, and a second DC link coupled between the second rectifier and the second inverter; and

a controller in electrical communication with the first power conversion module and the second power conversion module, wherein the controller is configured to generate a number of source side switching signals according to a winding-structure of the generator for providing to the first rectifier and the second rectifier, to reduce the voltage difference between a first DC link voltage at the first DC link and a second DC link voltage at the second DC link.