Power conversion system and method of operating the same

Patent metadata

Field	Value
Publication number	US-10256732-B2
Application number	US-201514885675-A
Country	US
Kind code	B2
Filing date	Oct 16, 2015
Priority date	Oct 16, 2015
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

Abstract

A medium voltage direct current (MVDC) collector system for renewable power generation facilities includes at least one renewable energy generation device. The MVDC collector system also includes at least one direct current (DC)-to-DC (DC/DC) power converter coupled to the at least one renewable energy generation device. The at least one DC/DC power converter is configured to shift a switching operation of the DC/DC power converter between full-wave conversion and half-wave conversion. The MVDC collector system further includes at least one controller coupled to the at least one DC/DC power converter. The at least one controller is configured to regulate shifting the switching operation of the at least one DC/DC power converter between full-wave conversion and half-wave conversion.

First claim

What is claimed is:

1. A medium voltage direct current (MVDC) collector system for renewable power generation facilities, said MVDC collector system comprising:
at least one renewable energy generation device;
at least one direct current (DC)-to-DC (DC/DC) power converter coupled to said at least one renewable energy generation device, said at least one DC/DC power converter configured to shift a switching operation of said DC/DC power converter between full-wave conversion and half-wave conversion;
at least one controller coupled to said at least one DC/DC power converter, said at least one controller configured to regulate shifting the switching operation of said at least one DC/DC power converter between full-wave conversion and half-wave conversion;
wherein said at least one DC/DC power converter comprises a full-bridge converter comprising an input DC link;
wherein the full-bridge converter comprises a plurality of switching devices, each switching device of said plurality of switching devices is directly connected to either a positive terminal or a negative terminal of the same input DC link; and
wherein the MVDC collector system further comprises a distributed energy storage system having a plurality of distributed energy storage devices, each distributed energy storage device includes storage batteries and momentum devices and is coupled to the said at least one DC/DC power converter through a distributed DC/DC power converter.

2. The MVDC collector system in accordance with claim 1 , wherein each switching device of said plurality of switching devices is coupled to said at least one controller, said at least one controller further configured to maintain at least a first portion of said plurality of switching devices in an OFF status and a second portion of said plurality of switching devices in an ON status to facilitate shifting the switching operation of said at least one DC/DC power converter from full-wave conversion to half-wave conversion.

3. The MVDC collector system in accordance with claim 1 , wherein said at least one DC/DC power converter comprises a plurality of DC/DC conversion modules, each DC/DC conversion module of said plurality of DC/DC conversion modules comprising an input section coupled to said at least one renewable energy generation device and an output section.

4. The MVDC collector system in accordance with claim 3 , said each DC/DC conversion module of said plurality of DC/DC conversion modules coupled to said at least one controller, said at least one controller configured to regulate switching said plurality of DC/DC conversion modules between an ON status and an OFF status to facilitate shifting the switching operation of said at least one DC/DC power converter from full-wave conversion to half-wave conversion.

5. The MVDC collector system in accordance with claim 1 , wherein said full bridge converter comprises a single resonant converter further comprising a high-frequency (HF) transformer and at least one resonant capacitor coupled in series with said HF transformer, said HF transformer comprising at least one inductive device, said at least one inductive device and said at least one resonant capacitor define a resonant tank circuit.

6. The MVDC collector system in accordance with claim 1 , wherein said at least one controller is further configured to use maximum power point tracking (MPPT) to regulate power conversion through said at least one DC/DC power converter.

7. The MVDC collector system in accordance with claim 6 , wherein said at least one DC/DC power converter comprises a plurality of switching devices, each switching device of said plurality of switching devices coupled to said at least one controller, said at least one controller further configured to maintain at least a first portion of said plurality of switching devices in an OFF status and a second portion of said plurality of switching devices in an ON status to facilitate shifting the switching operation of said at least one DC/DC power converter from full-wave conversion to half-wave conversion, said at least one controller further configured to regulate the switching frequency of said plurality of switching devices.

8. The MVDC collector system in accordance with claim 7 , wherein said plurality of switching devices is configured to switch within a range of frequencies between approximately 5 kiloHertz (kHz) and approximately 100 kHz.

9. The MVDC collector system in accordance with claim 7 wherein said at least one controller is further configured to regulate a voltage gain of said at least one DC/DC power converter through regulation of the switching frequency of said plurality of switching devices.

10. The MVDC collector system in accordance with claim 9 , wherein said at least one controller is further configured to:
receive real-time values of electric power transmitted through said at least one DC/DC power converter;
regulate the switching frequency of said plurality of switching devices to regulate the voltage gain of said at least one DC/DC power converter as a function of the real-time values of electric power transmitted through said at least one DC/DC power converter;
shift the switching operation of said at least one DC/DC power converter between full-wave conversion and half-wave conversion as a function of the real-time values of electric power transmitted through said at least one DC/DC power converter; and
decrease the switching frequency of said plurality of switching devices to decrease the voltage gain of said at least one DC/DC power converter under fault condition, thereby facilitating isolation of said at least one DC/DC power converter.

11. The MVDC collector system in accordance with claim 6 , wherein said at least one controller is further configured to regulate a voltage gain of said at least one DC/DC power converter as a function of load on said at least one DC/DC power converter.

12. The MVDC collector system in accordance with claim 1 , wherein said at least one DC/DC power converter comprises a plurality of DC/DC power converters and said at least one renewable energy generation device comprises a plurality of renewable energy generation devices, each DC/DC power converter of said plurality of DC/DC power converters and each renewable energy generation device of said plurality of renewable energy generation devices define a string of a plurality of strings, said MVDC collector system further comprising a MVDC bus, wherein said plurality of strings are coupled to said MVDC bus, each string of said plurality of strings further comprising at least one diode positioned between and coupled to said each DC/DC power converter and said MVDC bus.

13. The MVDC collector system in accordance with claim 12 , wherein said plurality of strings are devoid of DC-to-alternating current (AC) (DC/AC) converters, step-up transformers, and circuit breakers.

14. The MVDC collector system in accordance with claim 1 further comprising at least one electric power storage device coupled to said at least one DC/DC power converter.

15. A renewable energy generation facility comprising:
a direct current (DC) bus;
a plurality of renewable energy generation devices;
a plurality of direct current (DC)-to-DC (DC/DC) power converters, each DC/DC power converter of said plurality of DC/DC power converters coupled to at least one renewable energy generation device of said plurality of renewable energy generation devices, said each DC/DC power converter configured to shift a switching operation between full-wave conversion and half-wave conversion, each DC/DC power converter of said plurality of DC/DC power conver

Assignees

• Gen Electric

Inventors

• Zhou Rui
• Garces Luis Jose
• Raju Ravisekhar Nadimpalli
• Atalla Ashraf Said

Classifications

• H02J2101/25

  involving maximum power point tracking control for photovoltaic sources · CPC title

• H02J2101/24

  Photovoltaics · CPC title

• H02J2101/20

  Dispersed power generation using renewable energy sources · CPC title

• H02M3/33507 Primary

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title

• H02M3/33569

  having several active switching elements (H02M3/3353 takes precedence) · CPC title