CN110971129A - Power generation converter and wind generating set - Google Patents

Power generation converter and wind generating set Download PDF

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Publication number
CN110971129A
CN110971129A CN201911365542.8A CN201911365542A CN110971129A CN 110971129 A CN110971129 A CN 110971129A CN 201911365542 A CN201911365542 A CN 201911365542A CN 110971129 A CN110971129 A CN 110971129A
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CN
China
Prior art keywords
side converter
converter
direct current
current end
grid
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Pending
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CN201911365542.8A
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Chinese (zh)
Inventor
周党生
王武华
王琰
吕一航
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Shenzhen Hopewind Electric Co Ltd
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Shenzhen Hopewind Electric Co Ltd
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Priority to CN201911365542.8A priority Critical patent/CN110971129A/en
Publication of CN110971129A publication Critical patent/CN110971129A/en
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    • 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
    • H02M5/40—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 with intermediate conversion into dc
    • H02M5/42—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 with intermediate conversion into dc by static converters
    • H02M5/44—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 with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
    • H02M5/453—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 with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M5/458—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 with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M5/4585—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 with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only having a rectifier with controlled elements
    • 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
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M7/219—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration
    • 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
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • 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
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H02M7/53875—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current with analogue control of three-phase output
    • 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 for a generator set and a wind generating set, wherein the converter comprises a machine side converter and a grid side converter group consisting of at least two grid side converters, the three-phase alternating current end of the machine side converter is connected to a matched generator, and the three-phase alternating current end of each grid side converter is respectively connected to three-phase alternating current power supplies which are isolated from each other; the positive and negative direct current ends of each network side converter are cascaded to form the total positive and negative direct current ends of the network side converter group and are respectively connected to the positive and negative direct current ends of the machine side converter, the machine side converter and each network side converter are all fully-controlled converters, and the line voltage of the three-phase alternating current end of the machine side converter is matched with the direct current voltage between the positive and negative direct current ends of the machine side converter; the converter and the wind generating set can obviously improve the voltage grade of the generator side on the basis that the voltage of the converter grid side is relatively low, so that the current grade of a connecting cable between the converter and the generator is reduced, the system cost of the wind generating set is reduced, and the system efficiency is improved.

Description

Power generation converter and wind generating set
Technical Field
The invention relates to the field of power generation, in particular to a converter and a wind generating set in the field of wind power generation.
Background
As shown in fig. 1, a typical full power wind turbine generator system includes a wind turbine 11, a generator 12, a converter 13 and a transformer 14 connected in sequence. The converter 13 includes a machine side converter 15 and a grid side converter 16, an ac terminal of the machine side converter 15 is connected to the generator 12, and an ac terminal of the grid side converter 16 is connected to the transformer 14. As shown in fig. 2, in a wind turbine generator system, a transformer is usually mounted on a ground platform or a tower base platform inside a tower, a converter is mounted on the tower base platform inside the tower, and a generator is mounted in a nacelle capable of deflecting along with a main shaft of the wind turbine. The distance between the converter and the generator is thus close to a hundred meters or even larger. In a megawatt wind generating set, a generator and a converter with a 690V voltage level are generally adopted at present, and the converter with the 690V voltage level generally has better economical efficiency.
The conventional converter 13 comprises a network side converter and a machine side converter, both using a conventional two-level topology. The rated voltage of the grid side alternating current end and the rated voltage of the machine side alternating current end of the traditional full-power wind power converter are both 690 VAC.
However, with the continuous development of wind power generation, the single machine capacity of the wind generating set tends to increase continuously, and at present, the single machine capacity of the onshore wind generating set reaches 3 to 5MW, and the single machine capacity of the offshore wind generating set reaches 6 to 12 MW. In a wind generating set with large capacity, if a generator and a converter with a voltage grade of 690V are continuously adopted, currents on the generator 12 and the converter 13 and currents on a power cable between the generator 12 and the converter 13 are both remarkably increased, the large current causes difficulty in twisting the cable and reduction in reliability of the wind generating set, the improvement of electric energy conversion efficiency in the wind generating set is hindered, and the large current power cable and the large current distribution switch are high in cost, so that the problems of difficulty in engineering design, rapid increase in manufacturing cost and the like are caused. Therefore, it is a possible option to increase the internal voltage level of the wind turbine generator system, and a 1140V/3300V medium voltage converter, a generator and a corresponding transformer are now available in the art. However, the raising of the grid-side voltage is restricted by the relevant electrical equipment standards and grid management specifications, which affects the popularization of such technical solutions. Patent CN201120077035.7 proposes to use a form of three single-phase power unit chains based on single-phase H-bridge cascade to boost the voltage of the generator and maintain the secondary voltage of the transformer at a low voltage level, as shown in fig. 3, this scheme can reduce the current on the generator and its connected power cable, but there is single-phase power ripple on the dc bus in its power unit, which affects the voltage utilization rate, power quality and control performance; in addition, the number of power units and the number of connecting cables between the power units and the transformer are large, and the system is complex.
Disclosure of Invention
The invention aims to solve the technical problems of providing a wind generating set adopting a multi-winding transformer and a combined converter, overcoming the defects of difficult set design, high cost and insufficient electric energy conversion efficiency in the prior art of a large-capacity wind generator and overcoming the defects of single-phase power pulsation, large number of connecting cables and the like in the technical scheme of related patents.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the converter comprises a machine side converter and a grid side converter group consisting of at least two grid side converters, wherein the three-phase alternating current end of the machine side converter is connected to a matched generator, and the three-phase alternating current end of each grid side converter is respectively connected to three-phase alternating current power supplies which are isolated from each other; the positive direct current end and the negative direct current end of each network side converter are mutually cascaded to form a total positive direct current end and a total negative direct current end of a network side converter group, the total positive direct current end and the total negative direct current end of the network side converter group are respectively connected to the positive direct current end and the negative direct current end of the machine side converter, the machine side converter and each network side converter are all fully-controlled converters, the line voltage of the three-phase alternating current end of the machine side converter is matched with the direct current voltage between the positive direct current end and the negative direct current end of the machine side converter, and the line voltage of the three-phase alternating current end of each network side converter is matched with the direct current voltage between the positive. The full-control converter is a power converter based on a full-control power semiconductor device, supports bidirectional flow of active power and regulation of reactive power, and is suitable for application occasions such as new energy power generation.
Preferably, the machine side converter further comprises one or more intermediate dc terminals having a potential between the positive and negative dc terminal potentials, the intermediate dc terminals being connected to respective intermediate dc terminals having a potential between the corresponding potentials of the total positive and negative dc terminal potentials of the grid side converter group.
Preferably, an intermediate dc terminal between the potentials of the total positive and negative dc terminals of the grid-side converter group is connected to ground.
Preferably, the grid-side converter adopts a two-level three-phase fully-controlled bridge or a three-level three-phase fully-controlled bridge.
Preferably, the machine side converter adopts a three-level three-phase fully-controlled bridge, a five-level three-phase fully-controlled bridge or a modular multi-level fully-controlled bridge.
Preferably, the grid-side converter adopts a two-level three-phase fully-controlled bridge, and the machine-side converter adopts a three-level three-phase fully-controlled bridge.
Based on a converter that provides, provide a wind generating set, including fan, generator, converter and the transformer that connects gradually, its characterized in that: the transformer is a multi-winding transformer and comprises at least two sets of secondary three-phase windings which are isolated from each other; the converter comprises a machine side converter and a network side converter group consisting of at least two network side converters, the number of the network side converters is matched with the number of sets of secondary three-phase windings of the multi-winding transformer, the three-phase alternating current end of the machine side converter is connected to a matched generator, and the three-phase alternating current end of each network side converter is respectively connected to the corresponding secondary three-phase winding of the multi-winding transformer; the positive direct current end and the negative direct current end of each network side converter are mutually cascaded to form a total positive direct current end and a total negative direct current end of a network side converter group, the total positive direct current end and the total negative direct current end of the network side converter group are respectively connected to the positive direct current end and the negative direct current end of the machine side converter, the machine side converter and each network side converter are all fully-controlled converters, the line voltage between the three-phase alternating current ends of the machine side converter is matched with the direct current voltage between the positive direct current end and the negative direct current end of the machine side converter, and the line voltage between the three-phase alternating current ends of each network side converter is matched with the direct current voltage between the positive direct current.
Preferably, the machine side converter of the converter used in the wind park further comprises one or more intermediate dc terminals with a potential between the positive and negative dc terminal potentials, which intermediate dc terminals are connected to each intermediate dc terminal with a potential between the corresponding potential of the total positive and negative dc terminal potentials of the grid side converter group.
Preferably, the potential of the converter used by the wind power generation unit is between the potentials of the total positive and negative dc terminals of the grid-side converter group, and an intermediate dc terminal is grounded.
Preferably, the output voltages of the sets of secondary windings of the transformer used by the wind turbine generator system are partially out of phase.
Preferably, the secondary windings of the transformer used by the wind generating set are connected in a delta connection mode or a star connection mode, or a part of the windings are connected in a delta connection mode, and the other windings are connected in a star connection mode.
Compared with the prior art, the wind generating set has the beneficial effects that:
1. the voltage grade of the generator side can be obviously improved through the multi-level machine side converter, for example, the voltage grade is more than 1000V, so that the current grade of a connecting cable between the converter and the generator is reduced, the design difficulty and the system cost of the wind turbine generator are reduced, and the system efficiency is improved.
2. Through a plurality of network side converters with isolated AC sides and cascaded DC sides, the requirement of the multi-level machine side converter on the voltage of the DC end can be met, and the network side voltage can be maintained at a relatively low voltage level, such as 690V, so that large impact is not formed on the original network design and management specifications.
3. The system has simple structure and convenient implementation.
Drawings
Fig. 1 is a schematic diagram of the basic components of a conventional wind turbine generator system.
Fig. 2 is a schematic diagram of a basic structural layout of a conventional wind turbine generator system.
Fig. 3 is a schematic view of a wind turbine generator set proposed in the prior art.
Fig. 4 is a schematic diagram of a general embodiment of the current transformer of the present invention.
Fig. 5 is a schematic view of an overall embodiment of a wind park of the present invention.
Fig. 6 is a structural connection diagram of an embodiment of a converter according to a first embodiment of the present invention.
Fig. 7 is a connection diagram of a configuration of an embodiment of a converter according to a second embodiment of the present invention.
Fig. 8 is a structural connection diagram of an embodiment of a converter and a wind turbine generator system according to a third embodiment of the present invention.
Fig. 9 is a structural connection diagram of an embodiment of a converter and a wind turbine generator system according to a fourth embodiment of the present invention.
Fig. 10 is a block diagram of 3 typical circuits of the side converter of the converter according to the fourth embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the general embodiments, examples and the accompanying drawings. It should be understood that the general description and specific examples, while indicating embodiments of the invention, are given by way of illustration only.
The implementation of the present invention is described in detail below with reference to general embodiments.
General description of the embodiments
As shown in the solid line diagram of fig. 4, in the present embodiment, a converter for a generator set (abbreviated as a converter) is provided, which includes 1 machine-side converter and a grid-side converter group composed of n (n is a natural number, and n >1) grid-side converters. The machine side converter comprises a three-phase current terminal MAC, a positive direct current terminal MDC-P and a negative direct current terminal MDC-N. The potential of the positive dc terminal MDC-P of the machine side converter is higher than the potential of the negative dc terminal MDC-N of the machine side converter. The n network side converters can be named as a network side converter 1, a network side converter 2, network side converters 3 and … and a network side converter n respectively and are connected with three-phase current-crossing ends of external mutually-isolated alternating current power supplies respectively. The grid-side converter j comprises at least one three-phase current-intersecting terminal GAC (j), a positive direct current terminal GDC (j) -P and a negative direct current terminal GDC (j) -N. The potential of the positive direct current terminal GDC (j) -P of the grid-side converter j is higher than the voltage of the negative direct current terminal GDC (j) -N thereof.
The positive and negative direct current ends of the N grid-side converters are connected in cascade, namely, the negative direct current end GDC (1) -N of the grid-side converter 1 is connected with the positive direct current end GDC (2) -P of the grid-side converter 2, the negative direct current end GDC (2) -N of the grid-side converter 2 is connected with the positive direct current end GDC (3) -P of the grid-side converter 3, …, until the negative direct current end GDC (N-2) -N of the grid-side converter (N-2) is connected with the positive direct current end GDC (N-1) -P of the converter (N-1), and the negative direct current end GDC (N-1) -N of the grid-side converter (N-1) is connected with the positive direct current end GDC (N) -P of the grid-side converter N. Thus, after the cascade connection, the positive DC terminals GDC (1) -P of the grid-side converter 1 form the total positive DC terminal DC-P of the grid-side converter group, and the negative DC terminals GDC (N) -N of the grid-side converter N form the total negative DC terminal DC-N of the grid-side converter group.
The positive direct current terminal MDC-P of the machine side converter is connected to the total positive direct current terminal DC-P of the network side converter group, and the direct current terminal MDC-N of the machine side converter is connected to the total negative direct current terminal DC-N of the network side converter group.
All the n network side converters and the machine side converters in the converter are all fully-controlled converters, the fully-controlled converters are power converters based on fully-controlled power semiconductor devices, bidirectional flow of active power and adjustment of reactive power are supported, and the converter is suitable for application occasions such as new energy power generation.
Preferably, as shown by the dotted line in fig. 4, the converter further comprises m intermediate DC terminals of the machine-side converter connected to the grid-side converter group and having a potential between the DC-P potential and the DC-N potential, and the intermediate DC terminals (machine-side intermediate DC terminals) connected to each other at the machine-side converter are named: MDC-O1, MDC-O2, …, MDC-O (m-2), MDC-O (m-1), MDC-O (m), and the potential satisfies: DC-P potential > MDC-O1 potential > MDC-O2 potential > … > MDC-O (m-2) potential > MDC-O (m-1) potential > MDC-O (m) potential > DC-N potential; the interconnected intermediate dc terminals located at the grid-side converter groups (grid-side intermediate dc terminals) are named: GDC-O1, GDC-O2, …, GDC-O (m-2), GDC-O (m-1), GDC-O (m), and the potentials satisfy: DC-P potential > GDC-O1 potential > GDC-O2 potential > … potential > GDC-O (m-2) potential > GDC-O (m-1) potential > GDC-O (m) potential > DC-N potential. It should be noted that, there are possibilities that the number of all the intermediate DC terminals of the machine side converter and the grid side converter group between the DC-P potential and the DC-N potential is greater than m, and there are also possibilities that the number of the intermediate DC terminals of the machine side converter and the number of the intermediate DC terminals of the grid side converter group are not equal, and according to actual requirements, m machine side intermediate DC terminals are selected to be correspondingly connected with m grid side intermediate DC terminals having equal potentials, and the remaining machine side intermediate DC terminals are not connected with the grid side intermediate DC terminals.
Preferably, the grid side converter group of the converter has a grid side intermediate direct current end with the potential between the DC-P potential and the DC-N potential, and the grounding has the effect of reducing the voltage of the system to the ground.
Preferably, each grid-side converter in the converter can adopt a two-level three-phase fully-controlled bridge or a three-level three-phase fully-controlled bridge.
Preferably, each machine side converter in the converter can adopt a scheme that the number of levels such as a three-level three-phase fully-controlled bridge, a five-level three-phase fully-controlled bridge or a modular multi-level fully-controlled bridge is higher than that of a grid side converter. It should be noted that a modular multilevel converter (abbreviated as MMC) is a solution different from the H-bridge cascaded converter (abbreviated as HBC) proposed in the background patent. The H-bridge cascade can only be applied to the ac side, and the dc sides of the network-side converters of the corresponding power units must be isolated from each other, so that the dc side cascade method provided by the present invention cannot be adopted.
As shown in fig. 5, the converter for a generator set of the present invention is applied to a wind turbine generator set, the wind turbine generator set includes a fan, a generator, the converter of the present invention and a transformer which are connected in sequence, the transformer is a multi-winding transformer and includes at least two sets of three-phase windings on the secondary side which are isolated from each other; the converter comprises a machine side converter and a network side converter group consisting of at least two network side converters, the number of the network side converters is matched with the number of sets of secondary three-phase windings of the multi-winding transformer, the three-phase alternating current end of the machine side converter is connected to a matched generator, and the three-phase alternating current end of each network side converter is respectively connected to the corresponding secondary three-phase windings of the multi-winding transformer.
Preferably, the machine side converter of the converter used by the wind turbine generator system further comprises one or more intermediate dc terminals with a potential between the potentials of the positive and negative dc terminals, and the intermediate dc terminals are connected to the intermediate dc terminals of the corresponding potential after the positive and negative dc terminals of each grid side converter are cascaded with each other.
Preferably, after the positive and negative dc ends of each grid-side converter of the converter used by the wind generating set are cascaded with each other, one intermediate dc end at the intermediate potential is grounded, and the grounding has the function of reducing the system grounding voltage.
Preferably, phase differences exist between output voltages of sets of secondary windings of the transformer, for example, half of the secondary windings are connected in a delta shape, and half of the secondary windings are connected in a star shape, so that current harmonics of the primary windings of the transformer can be reduced; for example, the transformer is provided with n secondary windings, and the phase shift angle between each set of secondary windings is 120 degrees/n, so that the current harmonic of the primary winding of the transformer can be further reduced.
Preferably, the connection mode of each set of secondary windings of the converter is selected from delta connection and star connection, and the connection mode can be completely delta connection, also can be completely star connection, or can be partially delta connection, and the connection mode of other windings is star connection, and the connection modes of the windings adopting the star connection and the delta connection are beneficial to reducing the overall cost of the transformer.
The following describes the implementation of the present invention in detail with reference to specific embodiments.
Embodiment 1
As shown in fig. 6, in the present embodiment, a converter for a generator set is provided, which includes a machine side converter, a grid side converter 1 and a grid side converter 2, where the machine side converter is a three-phase neutral point clamped three-level (NPC) fully-controlled bridge, and both the grid side converter 1 and the grid side converter 2 are two-level three-phase fully-controlled bridges.
The grid-side converter j comprises a group of three-phase current-intersecting ends GAC (j), a positive direct current end GDC (j) -P and a negative direct current end GDC (j) -N (j is a serial number of the grid-side converter); the machine side converter is provided with a group of three-phase current terminals MAC, a positive direct current terminal MDC-P and a negative direct current terminal MDC-N.
The three-phase alternating current terminal GAC (1) of the grid-side converter 1 and the three-phase alternating current terminal GAC (2) of the grid-side converter 2 are respectively connected to two groups of mutually isolated three-phase power supplies.
The negative direct current end GDC (1) -N of the grid-side converter 1 is connected with the positive direct current end GDC (2) -P of the grid-side converter 2, after the cascade connection, the positive direct current end GDC (1) -P of the grid-side converter 1 forms the total positive direct current end DC-P of the grid-side converter group, and the negative direct current end GDC (2) -N of the grid-side converter 2 forms the total negative direct current end DC-N of the grid-side converter group. The positive direct current terminal MDC-P of the machine side converter is connected to the total positive direct current terminal DC-P of the network side converter group, and the negative direct current terminal MDC-N of the machine side converter is connected to the total negative direct current terminal DC-N of the network side converter group.
As an example, the basic design parameters of the grid-side converter are as follows:
grid side converter semiconductor switch: withstand voltage value UGigbt-block1700V IGBT devices;
grid-side converter diode: withstand voltage value UGdiode-block1700V diode device;
three-phase ac line voltage rating of the grid-side converter: u shapeGAC＝690VAC；
The voltage difference between the positive direct current end and the negative direct current end of the grid-side converter is as follows: u shapeGDC＝1100VDC；
As an example, the basic design parameters of the machine side converter are as follows:
side converter semiconductor switch: withstand voltageValue UMigbt-block1700V IGBT devices;
machine side converter diode: withstand voltage value UMdiode-block1700V diode device;
three-phase ac line voltage rating of machine side converter: u shapeMAC＝1380VAC；
The voltage difference between the positive direct current end and the negative direct current end of the machine side converter is as follows: u shapeMDC＝2200VDC；
Checking basic design parameters:
the grid-side converter adopts a three-phase two-level fully-controlled bridge converter scheme, the direct-current voltage of the converter is required to be less than the withstand voltage of a power semiconductor device, and a certain design margin needs to be reserved for the peak voltage in the conversion process: here UGDC1100V is significantly less than UGigbt-block＝UGdiode-block1700V, so the design requirement is met; meanwhile, the direct-current voltage of the grid-side converter is still required to be larger than the peak value of the voltage of the three-phase alternating-current end line of the grid side, and a certain design allowance is reserved, wherein U isGDC1100V is significantly higher than
Figure BDA0002338325460000091
Thus meeting the design requirements.
The machine side converter uses a three-phase midpoint embedded three-level fully controlled bridge converter (NPC) scheme, the direct-current voltage of the machine side converter is required to be less than 2 times of the withstand voltage of a power semiconductor device, and a certain design margin needs to be reserved for the peak voltage in the current conversion process: here UMDC2200V significantly less than
Figure BDA0002338325460000092
Therefore, the design requirements are met; meanwhile, the direct current voltage of the machine side converter is still required to be larger than the peak value of the voltage of the machine side three-phase alternating current terminal line, and a certain design allowance is reserved, wherein U isMDC2200V significantly higher than
Figure BDA0002338325460000093
Thus meeting the design requirements.
In this embodiment, using 1700V withstand voltage semiconductor IGBTs and diode devices, the ac voltage of the converter side converter can be raised to 1380VAC twice the external ac power line voltage under the external ac power line voltage 690 VAC. Therefore, the current grade of a connecting cable between the converter and the generator is remarkably reduced, the design difficulty and the system cost of the unit are reduced, the system efficiency is improved, the requirement of the multi-level machine side converter on the direct current end voltage is met, meanwhile, the grid side voltage is maintained at a relatively low voltage grade, large impact is not formed on the original grid-related design and management specification, and the unit formed by using the converter has the advantages of simple structure, convenience in implementation and the like.
Example II
As shown in fig. 7, in the present embodiment, a converter for a generator set is provided, which includes a machine side converter, a grid side converter 1 and a grid side converter 2, where the grid side converter 1 and the grid side converter 2 are both three-phase neutral-point clamped three-level (NPC) fully-controlled bridges, and the machine side converter is a three-phase five-level fully-controlled bridge.
The grid-side converter j comprises a group of three-phase current-intersecting ends GAC (j), a positive direct current end GDC (j) -P and a negative direct current end GDC (j) -N (j is a serial number of the grid-side converter); the machine side converter is provided with a group of three-phase current terminals MAC, a positive direct current terminal MDC-P and a negative direct current terminal MDC-N.
The three-phase alternating current terminal GAC (1) of the grid-side converter 1 and the three-phase alternating current terminal GAC (2) of the grid-side converter 2 are respectively connected to two groups of mutually isolated three-phase power supplies.
The negative direct current end GDC (1) -N of the grid-side converter 1 is connected with the positive direct current end GDC (2) -P of the grid-side converter 2, after the cascade connection, the positive direct current end GDC (1) -P of the grid-side converter 1 forms the total positive direct current end DC-P of the grid-side converter group, and the negative direct current end GDC (2) -N of the grid-side converter 2 forms the total negative direct current end DC-N of the grid-side converter group. The positive direct current terminal MDC-P of the machine side converter is connected to the total positive direct current terminal DC-P of the network side converter group, and the negative direct current terminal MDC-N of the machine side converter is connected to the total negative direct current terminal DC-N of the network side converter group.
The machine side converter has 3 machine side intermediate dc terminals: MDC-O1, MDC-O2 and MDC-O3, and the potential satisfies: the MDC-P potential > MDC-O1 potential > MDC-O2 potential > MDC-O3 potential > MDC-N potential, and 3 grid side intermediate direct current ends are arranged between the total positive and negative direct current ends formed after the grid side converter 1 and the grid side converter 2 are cascaded: GDC-O1, GDC-O2, GDC-O3, and the potential satisfies: GDC (1) -P potential GDC-O1 potential > GDC-O2 potential ═ GDC (1) -N potential ═ GDC (2) -P potential > GDC-O3 potential > GDC (2) -N potential, and machine side intermediate direct current terminals MDC-O1, MDC-O2 and MDC-O3 are sequentially connected with grid side intermediate direct current terminals GDC-O1, GDC-O2 and GDC-O3.
And the middle direct current end GDC-O2 on the network side is grounded.
As an example, the basic design parameters of the grid-side converter are as follows:
the topology scheme of the network side converter is as follows: a three-phase neutral point clamped three-level (NPC) fully-controlled bridge;
grid side converter semiconductor switch: withstand voltage value UGigbt-block1200V IGBT device;
grid-side converter diode: withstand voltage value UGdiode-block1200V diode device;
three-phase ac line voltage rating of the grid-side converter: u shapeGAC＝900VAC；
Voltage difference between positive and negative dc terminals of the grid-side converter: u shapeGDC+＝1500VDC；
Voltage difference between the positive dc terminal of the grid-side converter 1 and the grid-side intermediate dc terminal GDC-O1: u shapeGDC+＝750VDC
The voltage difference between the grid side intermediate dc terminal GDC-O1 and the negative dc terminal of the grid side converter 1: u shapeGDC-＝750VDC
As an example, the basic design parameters of the machine side converter are as follows:
machine side converter topology: a three-phase five-level fully-controlled bridge;
side converter semiconductor switch: withstand voltage value UMigbt-block1200V IGBT device;
machine side converter diode: withstand voltage value UMdiode-block1200V diode device;
three-phase ac line voltage rating of machine side converter: u shapeMAC＝1800VAC；
Machine sideVoltage difference between positive and negative dc terminals of the converter: u shapeMDC＝3000VDC；
Voltage difference between positive dc terminal of machine side converter and machine side intermediate dc terminal 1: u shapeMDC1＝750VDC；
Voltage difference between the intermediate dc terminal 1 of the machine side converter and the intermediate dc terminal 2 of the machine side converter: u shapeMDC2＝750VDC；
Voltage difference between the intermediate dc terminal 2 of the machine side converter and the intermediate dc terminal 3 of the machine side converter: u shapeMDC3＝750VDC；
Voltage difference between the intermediate dc terminal 3 and the negative dc terminal of the machine side converter: u shapeMDC4＝750VDC；
Checking basic design parameters:
the grid-side converter uses a three-phase neutral point clamped three-level (NPC) converter scheme, the direct-current voltage of the converter is required to be less than 2 times of the withstand voltage of a power semiconductor device, and a certain design margin needs to be reserved for the peak voltage in the conversion process: here UGDC1500V is significantly less than
Figure BDA0002338325460000111
Therefore, the design requirements are met; meanwhile, the direct-current voltage of the grid-side converter is still required to be larger than the peak value of the voltage of the three-phase alternating-current end line of the grid side, and a certain design allowance is reserved, wherein U isGDC1500V is significantly higher than
Figure BDA0002338325460000112
Thus meeting the design requirements.
The machine side converter adopts a three-phase five-level fully-controlled bridge converter scheme, the direct-current voltage of the machine side converter is required to be less than 4 times of the withstand voltage of a power semiconductor device, and a certain design margin needs to be reserved for the peak voltage in the conversion process: here UMDC3000V is significantly less than
Figure BDA0002338325460000121
Therefore, the design requirements are met; meanwhile, the direct current voltage of the machine side converter is still required to be larger than the peak value of the voltage of the machine side three-phase alternating current terminal line, and a certain design allowance is reserved, wherein U isMDC3000V is significantly higher than
Figure BDA0002338325460000122
Thus meeting the design requirements.
In this embodiment, using the 1200V withstand voltage semiconductor IGBT and the diode device, the ac voltage of the converter side converter can be raised to 1800VAC twice the external power supply voltage under the 900VAC external power supply voltage condition. Therefore, the current grade of a connecting cable between the converter and the generator is remarkably reduced, the design difficulty and the system cost of the unit are reduced, the system efficiency is improved, the requirement of the multi-level machine side converter on the direct current end voltage is met, meanwhile, the grid side voltage is maintained at a relatively low voltage grade, large impact is not formed on the original grid-related design and management specification, and the unit formed by using the converter has the advantages of simple structure, convenience in implementation and the like.
Example three
As shown in fig. 8, in the present embodiment, a wind turbine generator set is provided, where the wind turbine generator set includes a wind turbine, a generator, a converter and a transformer, the generator includes a set of three-phase cross current terminals, the converter includes a machine side converter, a grid side converter 1 and a grid side converter 2, and the transformer includes a set of three-phase primary windings and two sets of three-phase secondary windings isolated from each other. In the adopted converter, a grid-side converter 1 and a grid-side converter 2 are both two-level three-phase fully-controlled bridges, and a machine-side converter is a three-phase neutral-point clamped three-level (NPC) fully-controlled bridge.
The grid-side converter j comprises a group of three-phase current-intersecting ends GAC (j), a positive direct current end GDC (j) -P and a negative direct current end GDC (j) -N (j is a serial number of the grid-side converter); the machine side converter is provided with a group of three-phase current terminals MAC, a positive direct current terminal MDC-P and a negative direct current terminal MDC-N.
The fan is connected with the generator, the three-phase alternating current end of the generator is connected with the three-phase alternating current end MAC of the machine side converter of the converter, the three-phase alternating current end GAC (1) of the grid side converter 1 of the converter is connected with the secondary winding 1 of the transformer, and the converter 2 of the converter is formed by connecting the three-phase alternating current end GAC (2) with the secondary winding 2 of the transformer.
The negative direct current end GDC (1) -N of the grid-side converter 1 is connected with the positive direct current end GDC (2) -P of the grid-side converter 2, after the cascade connection, the positive direct current end GDC (1) -P of the grid-side converter 1 forms the total positive direct current end DC-P of the grid-side converter group, and the negative direct current end GDC (2) -N of the grid-side converter 2 forms the total negative direct current end DC-N of the grid-side converter group. The positive direct current terminal MDC-P of the machine side converter is connected to the total positive direct current terminal DC-P of the network side converter group, and the direct current terminal MDC-N of the machine side converter is connected to the total negative direct current terminal DC-N of the network side converter group.
The machine side converter has 1 machine side intermediate dc terminals: MDC-O1, and the potential satisfies: the MDC-P potential is more than MDC-O1 potential and more than MDC-N potential, a negative direct current end of the grid-side converter 1 and a positive direct current end of the grid-side converter 2 are cascaded to form a grid-side intermediate direct current end GDC-O1, and the machine-side intermediate direct current end MDC-O1 is connected with the grid-side intermediate direct current end GDC-O1.
And the middle direct current end GDC-O1 on the network side is grounded.
The basic design parameters of the net-side converter and the machine-side converter are the same as those of embodiment one.
The basic design parameters of the generator are as follows:
ac rated line voltage of generator: u shapeMotor＝1380VAC
The basic design parameters of the transformer are as follows:
primary winding connection: a triangle shape;
and (3) connecting a secondary winding 1: a triangle shape;
secondary winding 1 ac rated line voltage: u shapeGtran1＝690VAC
And (3) connecting a secondary winding 2: a star shape;
secondary winding 2 ac rated line voltage: u shapeGtran2＝690VAC
The rated line voltage of the machine side of the converter is 1380VAC equal to the rated line voltage of the alternating current of the generator, the rated line voltage of the grid-side converter 1 of the converter is 690VAC equal to the rated line voltage of the secondary winding 1 of the transformer, the rated line voltage of the grid-side converter 2 of the converter is 690VAC equal to the rated line voltage of the secondary winding 2 of the transformer, and the rated parameters of the generator, the converter and the transformer are designed and matched.
In the embodiment, 1700V voltage-resistant semiconductor IGBT and diode devices are used, the alternating current voltage of the generator can be increased to 1380VAC which is twice the secondary voltage of the transformer under the condition that the secondary voltage of the transformer is 690VAC, so that the current level of a connecting cable between the converter and the generator is remarkably reduced, the design difficulty and the system cost of the wind turbine generator are reduced, the system efficiency is improved, the requirement of a multi-level machine side converter on the direct current end voltage is met, meanwhile, the network side voltage is maintained at a relatively low voltage level, and large impact is not formed on the original network-related design and management specifications.
Example four
As shown in fig. 9, in the present embodiment, a wind turbine generator set is provided, where the generator includes a set of three-phase cross current terminals, the converter includes a machine-side converter and 4 grid-side converters, and the transformer includes a set of three-phase primary windings and 4 sets of three-phase secondary windings isolated from each other. In the adopted converter, 4 network side converters are all two-level three-phase fully-controlled bridges, and the machine side converter is a Modular Multilevel (MMC) three-phase fully-controlled bridge. The side converter uses 24 MMC bridge modules in total, and a commonly used MMC module circuit is shown in FIG. 10. The MMC module used comprises two ac terminals HAC1 and HAC2, two dc terminals HDC1 and HDC 2.
The grid-side converter j comprises a group of three-phase current-intersecting ends GAC (j), a positive direct current end GDC (j) -P and a negative direct current end GDC (j) -N (j is a serial number of the grid-side converter); the machine side converter is provided with a group of three-phase current terminals MAC, a positive direct current terminal MDC-P and a negative direct current terminal MDC-N.
The fan is connected with the generator, the three-phase AC end of the generator is connected with the three-phase AC end MAC of the machine side converter of the converter, and the 4 sets of network side converters GAC (a) of the converter are respectively connected with the secondary windings corresponding to the transformer.
The negative direct current end GDC (1) -N of the grid-side converter 1 is connected with the positive direct current end GDC (2) -P of the grid-side converter 2, the negative direct current end GDC (2) -N of the grid-side converter 2 is connected with the positive direct current end GDC (3) -P of the grid-side converter 3, and the negative direct current end GDC (3) -N of the grid-side converter 3 is connected with the positive direct current end GDC (4) -P of the grid-side converter 4. After the cascade connection, the positive direct current terminals GDC (1) -P of the grid-side converter 1 form the total positive direct current terminal DC-P of the grid-side converter group, and the negative direct current terminals GDC (4) -N of the grid-side converter 4 form the total negative direct current terminal DC-N of the grid-side converter group. The positive direct current terminal MDC-P of the machine side converter is connected to the total positive direct current terminal DC-P of the network side converter group, and the negative direct current terminal MDC-N of the machine side converter is connected to the total negative direct current terminal DC-N of the network side converter group.
In order to reduce the voltage to ground of the system, the negative direct current end GDC (2) -N of the grid-side converter 2 is connected with the positive direct current end GDC (3) -P of the grid-side converter 3, and then grounding is carried out.
As an example, the basic design parameters of all grid-side converters are as follows:
the topology scheme of the network side converter is as follows: a three-phase two-level fully controlled bridge converter;
grid side converter semiconductor switch: withstand voltage value UGigbt-block1700V IGBT devices;
grid-side converter diode: withstand voltage value UGdiode-block1700V diode device;
three-phase ac line voltage rating of the grid-side converter: u shapeGAC＝690VAC；
The voltage difference between the positive direct current end and the negative direct current end of the grid-side converter is as follows: u shapeGDC＝1100VDC；
The basic design parameters of the machine side converter are as follows:
machine side converter topology: a three-phase Modular Multilevel Converter (MMC);
side converter semiconductor switch: withstand voltage value UMigbt-block1700V IGBT devices;
machine side converter diode: withstand voltage value UMdiode-block1700V diode device;
direct-current terminal voltage of MMC module of machine side converter: u shapeHDC＝1100VDC；
AC of MMC module of machine side converterTerminal voltage: u shapeHAC＝690VAC；
Three-phase ac line voltage rating of machine side converter: u shapeMAC＝2760VAC；
The voltage difference between the positive direct current end and the negative direct current end of the machine side converter is as follows: u shapeMDC＝4400VDC；
The basic design parameters of the generator are as follows:
ac rated line voltage of generator: u shapeMotor＝2760VAC
The basic design parameters of the transformer are as follows:
primary winding connection: a triangle shape;
the phase difference between the secondary winding 1 and the primary winding is as follows: 60 degrees;
secondary winding 1 ac rated line voltage: u shapeGtran1＝690VAC；
And (3) connecting a secondary winding 2: 30 degrees;
secondary winding 2 ac rated line voltage: u shapeGtran2＝690VAC；
And (3) connecting a secondary winding: 0 degree;
secondary winding 3 ac rated line voltage: u shapeGtran2＝690VAC；
And 4, connecting a secondary winding: -30 °;
secondary winding 4 ac rated line voltage: u shapeGtran2＝690VAC；
Checking basic design parameters:
the grid-side converter adopts a three-phase two-level fully-controlled bridge converter scheme, the direct-current voltage of the converter is required to be less than the withstand voltage of a power semiconductor device, and a certain design margin needs to be reserved for the peak voltage in the conversion process: here UGDC1100V is significantly less than UGigbt-block＝UGdiode-block1700V, so the design requirement is met; meanwhile, the direct-current voltage of the grid-side converter is still required to be larger than the peak value of the voltage of the three-phase alternating-current end line of the grid side, and a certain design allowance is reserved, wherein U isGDC1100V is significantly higher than
Figure BDA0002338325460000161
Thus meeting the design requirements.
The machine side converter adopts a three-phase Modular Multilevel Converter (MMC) scheme, the direct-current end voltage of the machine side MMC module is required to be smaller than the withstand voltage of a power semiconductor device, and a certain design allowance needs to be reserved for the peak voltage in the conversion process: here UHDC1100V is significantly less than UMigbt-block＝UMdiode-block1700V, so the design requirement is met; requiring the DC voltage of the MMC module at the machine side to be larger than the peak value of the line voltage at the AC end of the module and reserving a certain design allowance, wherein U isHDC1100V is significantly higher than
Figure BDA0002338325460000162
Therefore, the design requirements are met; simultaneously, the direct current voltage of the machine side converter is required to be larger than the peak value of the voltage of the machine side three-phase alternating current terminal line, and a certain design margin is reserved, wherein U isMDC4400V is significantly higher than
Figure BDA0002338325460000163
Thus meeting the design requirements.
The rated line voltage of the machine side of the converter is 2760VAC equal to the rated line voltage of the alternating current of the generator, the rated line voltage of the 4 sets of network side converters of the converter is 690VAC equal to the rated line voltage of the 4 sets of secondary windings of the transformer, and the rated parameters of the generator, the converter and the transformer are designed and matched. Meanwhile, 4 sets of secondary windings of the transformer sequentially move towards the same angle to perform low-order harmonic cancellation, so that current harmonics of the primary side of the transformer can be further reduced, and the power quality is improved.
In this example, the ac voltage of the generator was boosted to four times 2760VAC as the secondary voltage of the transformer using 1700V withstand voltage semiconductor IGBTs and diode devices under the condition that the secondary voltage of the transformer was 690 VAC. Therefore, the current grade of a connecting cable between the converter and the generator is remarkably reduced, the design difficulty and the system cost of the wind turbine generator are reduced, the system efficiency is improved, the requirement of a multi-level machine side converter on the voltage of a direct current end is met, and meanwhile, the voltage of a grid side is maintained at a relatively low voltage grade.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (12)

1. A converter for generating set which characterized in that: the system comprises a machine side converter and a network side converter group consisting of at least two network side converters, wherein the three-phase alternating current end of the machine side converter is connected to a matched generator, and the three-phase alternating current end of each network side converter is respectively connected to three-phase alternating current power supplies which are isolated from each other; the positive direct current end and the negative direct current end of each network side converter are mutually cascaded to form a total positive direct current end and a total negative direct current end of a network side converter group, the total positive direct current end and the total negative direct current end of the network side converter group are respectively connected to the positive direct current end and the negative direct current end of the machine side converter, the machine side converter and each network side converter are all fully-controlled converters, the line voltage of the three-phase alternating current end of the machine side converter is matched with the direct current voltage between the positive direct current end and the negative direct current end of the machine side converter, and the line voltage of the three-phase alternating current end of each network side converter is matched with the direct current voltage between the positive.
2. The converter for a generator set of claim 1, wherein said fully controlled converter is a power converter based on fully controlled power semiconductor devices and supporting bi-directional flow of active power and regulation of reactive power.
3. The converter for a generator set according to claim 1, characterized in that said machine side converter further comprises one or more intermediate dc terminals having a potential between the positive and negative dc terminal potentials, which intermediate dc terminals are connected to respective intermediate dc terminals having a potential between the corresponding potential of the total positive and negative dc terminal potentials of said grid side converter group.
4. The converter according to claim 1, wherein an intermediate dc terminal between the potentials of the total positive and negative dc terminals of said grid-side converter group is connected to ground.
5. The converter for a generator set of claim 1, wherein each grid-side converter employs a two-level three-phase fully controlled bridge or a three-level three-phase fully controlled bridge.
6. The converter for a generator set of claim 1, wherein said machine side converter is a three-level three-phase fully controlled bridge, a five-level three-phase fully controlled bridge, or a modular multi-level fully controlled bridge.
7. The converter for a generator set of claim 1, wherein each said grid-side converter employs a two-level three-phase fully controlled bridge and said machine-side converter employs a three-level three-phase fully controlled bridge.
8. The utility model provides a wind generating set, includes fan, generator, converter and the transformer that connects gradually, its characterized in that: the transformer is a multi-winding transformer and comprises at least two sets of secondary three-phase windings which are isolated from each other; the converter comprises a machine side converter and a network side converter group consisting of at least two network side converters, the number of the network side converters is matched with the number of sets of secondary three-phase windings of the multi-winding transformer, the three-phase alternating current end of the machine side converter is connected to a matched generator, and the three-phase alternating current end of each network side converter is respectively connected to the corresponding secondary three-phase winding of the multi-winding transformer; the positive direct current end and the negative direct current end of each network side converter are mutually cascaded to form a total positive direct current end and a total negative direct current end of a network side converter group, the total positive direct current end and the total negative direct current end of the network side converter group are respectively connected to the positive direct current end and the negative direct current end of the machine side converter, the machine side converter and each network side converter are all fully-controlled converters, the line voltage of the three-phase alternating current end of the machine side converter is matched with the direct current voltage between the positive direct current end and the negative direct current end of the machine side converter, and the line voltage of the three-phase alternating current end of each network side converter is matched with the direct current voltage between the positive.
9. Wind park according to claim 8, wherein the converter side converter of said converter further comprises one or more intermediate DC terminals having a potential between the positive and negative DC terminal potentials, which intermediate DC terminals are connected to respective intermediate DC terminals having a potential between the corresponding potential of the total positive and negative DC terminal potentials of said grid side converter group.
10. Wind park according to claim 8, wherein an intermediate dc terminal between the potentials of the total positive and negative dc terminals of said grid-side converter group is connected to ground.
11. The wind turbine of claim 8, wherein the transformer has a phase difference between the output voltages of the sets of secondary windings.
12. The wind generating set according to claim 8, wherein the sets of secondary windings of the transformer are connected in a delta connection or a star connection, or some of the windings are connected in a delta connection and others in a star connection.
CN201911365542.8A 2019-12-26 2019-12-26 Power generation converter and wind generating set Pending CN110971129A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112290811A (en) * 2020-10-19 2021-01-29 上海电气风电集团股份有限公司 Three-level converter, power conversion device and zero-sequence current suppression method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112290811A (en) * 2020-10-19 2021-01-29 上海电气风电集团股份有限公司 Three-level converter, power conversion device and zero-sequence current suppression method
CN112290811B (en) * 2020-10-19 2021-11-05 上海电气风电集团股份有限公司 Three-level converter, power conversion device and zero-sequence current suppression method

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