CN114374222A - Converter system of direct current wind turbine generator - Google Patents

Converter system of direct current wind turbine generator Download PDF

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Publication number
CN114374222A
CN114374222A CN202111500529.6A CN202111500529A CN114374222A CN 114374222 A CN114374222 A CN 114374222A CN 202111500529 A CN202111500529 A CN 202111500529A CN 114374222 A CN114374222 A CN 114374222A
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CN
China
Prior art keywords
grid
converter
transformer
side converter
electric energy
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
CN202111500529.6A
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Chinese (zh)
Inventor
赵瑞斌
申旭辉
李春华
孙栩
秦猛
李铮
奚嘉雯
汤海雁
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Huaneng Clean Energy Research Institute
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Huaneng Clean Energy Research Institute
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Publication date
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Priority to CN202111500529.6A priority Critical patent/CN114374222A/en
Publication of CN114374222A publication Critical patent/CN114374222A/en
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/02—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc
    • H02M5/04—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters
    • H02M5/10—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Eletrric Generators (AREA)

Abstract

The invention discloses a converter system of a direct current wind turbine generator. The direct current wind turbine generator set comprises a generator and a converter system, wherein the generator is used for converting wind energy into first alternating current electric energy; the converter system comprises: a unit transformer and a grid-side converter; the output end of the generator is connected with the input end of the unit transformer, and the output end of the unit transformer is connected with the input end of the grid-side converter; the unit transformer is used for converting the first alternating current electric energy into second alternating current electric energy, and the grid-side converter is used for converting the second alternating current electric energy into direct current electric energy. Therefore, the transformer is arranged on the side of the wind turbine generator set, the circuit structure of the converter system of the direct-current wind turbine generator set is simplified, the switching frequency of the grid-side converter is low, the control difficulty and the running loss of the converter system are reduced, and the cost is saved.

Description

Converter system of direct current wind turbine generator
Technical Field
The invention relates to the technical field of energy, in particular to a converter system of a direct current wind turbine generator.
Background
At present, with the aggravation of the problem of energy shortage, people are urgently required to develop new energy to meet the energy demand of people. The wind power generation has the advantages of being renewable, environment-friendly and the like, and is widely applied, and particularly, offshore wind power is an important field of wind power generation. The wind power generation collection system is a power connection system which collects the electric energy of the wind generating set and transmits the electric energy to a wind power field boosting transformer substation or an electric load. However, the converter system of the dc wind turbine in the related art has the problems of complex circuit structure, difficult control, high cost, and the like.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the art described above.
Therefore, a first objective of the present invention is to provide a converter system of a dc wind turbine, which includes a turbine transformer and a grid-side converter, wherein the turbine transformer can convert a first ac power output by a generator into a second ac power, and the grid-side converter can convert the second ac power output by the turbine transformer into a dc power. Therefore, compared with the prior art that the converter system is mostly realized by adopting a machine side converter and a grid side isolation type converter, the converter system has the advantages that the transformer is arranged on the machine set side, the circuit structure of the converter system is simplified, the switching frequency of the grid side converter is low, the control difficulty and the operation loss of the converter system are reduced, and the cost is saved.
The embodiment of the first aspect of the invention provides a converter system of a direct current wind turbine generator, wherein the direct current wind turbine generator comprises a generator and the converter system, and the generator is used for converting wind energy into first alternating current electric energy;
the converter system comprises: a unit transformer and a grid-side converter; the output end of the generator is connected with the input end of the unit transformer, and the output end of the unit transformer is connected with the input end of the grid-side converter; the unit transformer is used for converting the first alternating current electric energy into second alternating current electric energy, and the grid-side converter is used for converting the second alternating current electric energy into direct current electric energy.
The converter system of the direct current wind turbine generator comprises a generator transformer and a grid-side converter, wherein the generator transformer can convert first alternating current electric energy output by a generator into second alternating current electric energy, and the grid-side converter can convert the second alternating current electric energy output by the generator transformer into direct current electric energy. Therefore, compared with the prior art that the converter system is mostly realized by adopting a machine side converter and a grid side isolation type converter, the converter system has the advantages that the transformer is arranged on the machine set side, the circuit structure of the converter system is simplified, the switching frequency of the grid side converter is low, the control difficulty and the operation loss of the converter system are reduced, and the cost is saved.
In addition, the converter system of the direct current wind turbine set proposed according to the above embodiment of the present invention may further have the following additional technical features:
in one embodiment of the invention the voltage level of the second alternating current electric energy is higher than the voltage level of the first alternating current electric energy.
In an embodiment of the present invention, the grid-side converter outputs the dc power, output ends of the grid-side converters of the plurality of dc wind turbines are connected in series, the plurality of dc wind turbines connected in series form a fan string, and an output end of the fan string is connected to a dc submarine cable.
In one embodiment of the invention, the wind power generation collecting system is composed of a plurality of direct current wind power generation sets and the direct current submarine cables, and the output end of the wind power generation collecting system is connected with the input end of the land power conversion station.
In one embodiment of the invention, the set transformer is a three-phase transformer.
In one embodiment of the invention, the set transformer is an isolation transformer.
In one embodiment of the invention, the grid-side converter is a three-phase AC-DC converter.
In one embodiment of the invention, the output voltage of the grid-side converter is a direct voltage.
In one embodiment of the invention, the topology of the grid-side converter is a three-phase multilevel structure.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic diagram of a DC wind turbine according to one embodiment of the present invention;
fig. 2 is a schematic connection diagram of a grid-side converter of a dc wind power plant according to an embodiment of the present invention;
FIG. 3 is a schematic view of a wind power generation collection system according to one embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The following describes a converter system of a dc wind turbine according to an embodiment of the present invention with reference to the drawings.
Fig. 1 is a schematic diagram of a dc wind turbine according to an embodiment of the present invention.
As shown in fig. 1, a direct current wind turbine 10 according to an embodiment of the present invention includes a generator 1 and a converter system 2. The converter system 2 includes a set transformer 21 and a grid-side converter 22.
In the embodiment of the present invention, the output terminal of the generator 1 is connected to the input terminal of the unit transformer 21, and the output terminal of the unit transformer 21 is connected to the input terminal of the grid-side converter 22.
In the embodiment of the present invention, the generator 1 is configured to convert wind energy into first ac power, the unit transformer 21 is configured to convert the first ac power into second ac power, and the grid-side converter 22 is configured to convert the second ac power into dc power.
In one embodiment, the voltage level of the dc power is higher than the voltage level of the first ac power, and the converter system 2 may boost the first ac power output by the generator 1 to the dc power. It should be noted that, the voltage level of the first ac power and the voltage level of the dc power can be set according to actual situations, and is not limited to this.
In one embodiment, the voltage level of the second ac power is higher than the voltage level of the first ac power, and the unit transformer 21 is a step-up transformer for stepping up the first ac power output by the generator 1 to the second ac power. It should be noted that, the voltage level of the first ac power and the voltage level of the second ac power can be set according to actual situations, and are not limited herein.
In the embodiment of the present invention, the topological structures of the unit transformer 21 and the grid-side converter 22 can be set according to actual situations, which is not limited herein.
In one embodiment, the unit transformer 21 is a three-phase transformer, and the unit transformer 21 may convert the first ac power output by the generator 1 into a three-phase second ac power.
In one embodiment, the unit transformer 21 is an isolation transformer, and in this case, the unit transformer 21 can achieve electrical isolation between the generator 1 and the grid-side converter 22, which helps to improve the stability and reliability of the wind power generation collection system. For example, the unit transformer 21 may include a three-phase isolation transformer and a single-phase isolation transformer.
In one embodiment, the grid-side converter 22 is a three-phase AC-DC converter, and the grid-side converter 22 can convert the second AC power output by the set transformer 21 into three-phase DC power.
In one embodiment, the output voltage of the grid-side converter 22 is a dc voltage.
In one embodiment, the topology of the grid-side converter 22 is a three-phase multilevel structure. The three-phase multilevel structure includes, but is not limited to, a three-phase half-bridge two-level structure, a single-phase three-level structure, a single-phase five-level structure, and the like, which are not limited herein. For example, the grid-side Converter 22 may be an MMC (Modular-Multilevel-Converter).
In one embodiment, the output frequency of at least one of the generator 1, the unit transformer 21, the grid-side converter 22 is less than the mains frequency. It should be noted that the output frequencies of the generator 1, the unit transformer 21, and the grid-side converter 22 may be set according to actual conditions, and are not limited herein. For example, the output frequency may be 50/3Hz (Hertz). Therefore, the output frequency of at least one of the generator 1, the unit transformer 21 and the grid-side converter 22 is smaller than the power frequency, the power transmission capacity and the power transmission distance of a power transmission line in the wind power generation collecting system are increased, and the stability and the reliability of the wind power generation collecting system are improved.
To sum up, the converter system of the dc wind turbine according to the embodiment of the present invention includes a turbine transformer and a grid-side converter, wherein the turbine transformer can convert the first ac power output by the generator into a second ac power, and the grid-side converter can convert the second ac power output by the turbine transformer into a dc power. Therefore, compared with the prior art that the converter system is mostly realized by adopting a machine side converter and a grid side isolation type converter, the converter system has the advantages that the transformer is arranged on the machine set side, the circuit structure of the converter system is simplified, the switching frequency of the grid side converter is low, the control difficulty and the operation loss of the converter system are reduced, and the cost is saved.
On the basis of any of the above embodiments, as shown in fig. 2, the grid-side converter 22 outputs dc power, the output ends of the grid-side converters 22 of the plurality of dc wind turbines 10 are connected in series, the plurality of dc wind turbines connected in series form one fan string 3, and the output end of the fan string 3 is connected with the dc submarine cable 4. It can be understood that the dc power output by the fan string 3 is the sum of the dc power output by the plurality of dc wind turbines 10 connected in series.
In one embodiment, as shown in fig. 2, the output of the wind turbine string 3 is connected to a dc sea cable 4, and the dc sea cable 4 is further connected to an onshore power conversion station 200. Therefore, the direct current electric energy output by the fan string can be directly transmitted to the onshore power conversion station through the direct current submarine cable.
Therefore, the output ends of the grid-side converters in the scheme can be connected in series to form direct current electric energy, the direct current electric energy output by the direct current wind turbine generator set can be boosted in a series connection mode, and an offshore booster station is not required to be arranged.
It should be noted that the connection modes of the multiple dc wind turbines 10 may also include other connection modes other than fig. 2, which is not limited herein.
On the basis of any of the above embodiments, as shown in fig. 3, the wind power generation collecting system 100 is composed of a plurality of direct current wind power generation sets 10 and a direct current submarine cable 4, and the output end of the wind power generation collecting system 100 is connected with the input end of the onshore power conversion station 200. Therefore, the wind power generation collecting system can directly send offshore wind power into the onshore power conversion station without arranging an offshore booster station, and the number of power transmission lines and the cost of the offshore wind power can be greatly reduced.
On the basis of any of the above embodiments, the wind power collection system 100 is arranged on an offshore load carrying device. It should be noted that the type of the offshore loading device is not limited too much, and for example, steel pipes, steel columns, and the like may be included.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (9)

1. The converter system of the direct current wind turbine generator is characterized in that the direct current wind turbine generator comprises a generator and a converter system, wherein the generator is used for converting wind energy into first alternating current electric energy;
the converter system comprises: a unit transformer and a grid-side converter;
the output end of the generator is connected with the input end of the unit transformer, and the output end of the unit transformer is connected with the input end of the grid-side converter;
the unit transformer is used for converting the first alternating current electric energy into second alternating current electric energy, and the grid-side converter is used for converting the second alternating current electric energy into direct current electric energy.
2. The system of claim 1, wherein the voltage level of the second AC power is higher than the voltage level of the first AC power.
3. The system of claim 1, wherein said grid-side converter outputs said dc power, and wherein said grid-side converter outputs of a plurality of said dc wind turbines are connected in series, and wherein said plurality of said dc wind turbines connected in series form a fan string, and wherein said fan string output is connected to a dc sea cable.
4. The system of claim 3, wherein the wind power collection system is composed of a plurality of said DC wind turbines and said DC sea cable, and an output end of said wind power collection system is connected to an input end of the onshore power conversion station.
5. The system according to any one of claims 1-4, wherein the unit transformer is a three-phase transformer.
6. The system according to any one of claims 1-4, wherein the unit transformer is an isolation transformer.
7. A system according to any of claims 1-4, characterized in that the grid-side converter is a three-phase AC-DC converter.
8. The system according to any of claims 1-4, characterized in that the output voltage of the grid-side converter is a direct voltage.
9. The system of claim 7, wherein the topology of the grid-side converter is a three-phase multilevel structure.
CN202111500529.6A 2021-12-09 2021-12-09 Converter system of direct current wind turbine generator Withdrawn CN114374222A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111500529.6A CN114374222A (en) 2021-12-09 2021-12-09 Converter system of direct current wind turbine generator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111500529.6A CN114374222A (en) 2021-12-09 2021-12-09 Converter system of direct current wind turbine generator

Publications (1)

Publication Number Publication Date
CN114374222A true CN114374222A (en) 2022-04-19

Family

ID=81139566

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111500529.6A Withdrawn CN114374222A (en) 2021-12-09 2021-12-09 Converter system of direct current wind turbine generator

Country Status (1)

Country Link
CN (1) CN114374222A (en)

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