CN219960136U - Wind generating set, wind power plant and wind power transmission system - Google Patents

Abstract

The utility model discloses a wind generating set, a wind power plant and a wind power transmission system, and belongs to the field of wind power generation. The wind generating set comprises a mechanical transmission structure, a generator, a machine side transformer, a modularized multi-level converter, an alternating current-direct current converter, a direct current-alternating current converter, a set load and an unloading circuit; the mechanical transmission structure is connected with the generator, the machine side transformer and the modularized multi-level converter are sequentially and electrically connected, the generator, the alternating current-direct current converter, the direct current-alternating current converter and the unit load are sequentially and electrically connected, the unloading circuit is electrically connected with the alternating current-direct current converter, and the unloading circuit is used for consuming part of electric energy output by the generator. According to the embodiment of the utility model, the safety of the wind generating set can be improved.

Description

Wind generating set, wind power plant and wind power transmission system

Technical Field

The utility model belongs to the field of wind power generation, and particularly relates to a wind generating set, a wind power plant and a wind power transmission system.

Background

The wind generating set is a device capable of converting wind energy into electric energy, and most of the wind generating set is arranged at a place with abundant wind resources for better capturing the wind energy, but the place with abundant wind resources is often remote and far away from a power grid, and the electric energy output by a plurality of wind generating sets is required to be collected and transmitted to the power grid for allocation by a power supply network.

In some cases, voltage drops or other problems may occur at grid connection points between the wind turbine and the power grid, so that electric energy on the wind turbine side is accumulated, and the safety of the wind turbine is reduced.

Disclosure of Invention

The embodiment of the utility model provides a wind generating set, a wind power plant and a wind power transmission system, which can improve the safety of the wind generating set.

In a first aspect, an embodiment of the present utility model provides a wind turbine generator set, including a mechanical transmission structure, a generator, a machine side transformer, a modular multilevel converter, an ac-dc converter, a dc-ac converter, a unit load and an unloading circuit; the mechanical transmission structure is connected with the generator, the machine side transformer and the modularized multi-level converter are sequentially and electrically connected, the generator, the alternating current-direct current converter, the direct current-alternating current converter and the unit load are sequentially and electrically connected, the unloading circuit is electrically connected with the alternating current-direct current converter, and the unloading circuit is used for consuming part of electric energy output by the generator.

In a second aspect, an embodiment of the present utility model provides a wind farm, including at least one group of wind turbine generator sets, where each group of wind turbine generator sets includes more than two wind turbine generator sets according to the first aspect, and power supply receiving ends of unit loads in the same group of wind turbine generator sets are connected in parallel.

In a third aspect, an embodiment of the present utility model provides a wind power transmission system, including the wind farm, the dc booster, the grid-side converter, the grid-side transformer, and the grid of the second aspect electrically connected in sequence.

The embodiment of the utility model provides a wind power generator set, a wind power plant and a wind power transmission system, wherein the wind power generator set comprises a mechanical transmission structure, a generator, a machine side transformer, a modularized multi-level converter, an alternating current-direct current converter, a direct current-alternating current converter, a unit load and an unloading circuit, the mechanical transmission structure is connected with the generator, the machine side transformer and the modularized multi-level converter are sequentially and electrically connected, the generator, the alternating current-direct current converter, the direct current-alternating current converter and the unit load are sequentially and electrically connected, and the unloading circuit is electrically connected with the alternating current-direct current converter. The unloading circuit can consume part of electric energy output by the generator under the condition that voltage drop occurs or other problems occur at grid connection points between the wind generating set and the power grid, so that risks caused by accumulation of electric energy on the side of the wind generating set are avoided, low voltage ride through capacity of the wind generating set is improved, and safety of the wind generating set is improved.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present utility model, the drawings that are needed to be used in the embodiments of the present utility model will be briefly described, and it is possible for a person skilled in the art to obtain other drawings according to these drawings without inventive effort.

FIG. 1 is a schematic diagram of a wind turbine generator system according to an embodiment of the present utility model;

FIG. 2 is a schematic view of a wind turbine generator system according to another embodiment of the present utility model;

FIG. 3 is a schematic diagram illustrating an exemplary configuration of the unloading circuit of FIG. 2 according to an embodiment of the present utility model;

FIG. 4 is a schematic diagram of an exemplary configuration of the unloading circuit of FIG. 1 according to an embodiment of the present utility model;

FIG. 5 is a schematic view of a wind turbine generator system according to another embodiment of the present utility model;

FIG. 6 is a schematic view of a wind turbine generator system according to another embodiment of the present utility model;

FIG. 7 is a schematic structural diagram of a wind farm according to an embodiment of the present utility model;

FIG. 8 is a schematic structural diagram of a wind farm according to another embodiment of the present utility model;

FIG. 9 is a schematic structural view of a wind farm according to a further embodiment of the present utility model;

fig. 10 is a schematic structural diagram of a wind power transmission system according to an embodiment of the present utility model.

Detailed Description

Features and exemplary embodiments of various aspects of the present utility model will be described in detail below, and in order to make the objects, technical solutions and advantages of the present utility model more apparent, the present utility model will be described in further detail below with reference to the accompanying drawings and the detailed embodiments. It should be understood that the particular embodiments described herein are meant to be illustrative of the utility model only and not limiting. It will be apparent to one skilled in the art that the present utility model may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the utility model by showing examples of the utility model.

The wind generating set is a device capable of converting wind energy into electric energy, and most of the wind generating set is arranged at a place with abundant wind resources for better capturing the wind energy, but the place with abundant wind resources is often remote and far away from a power grid, and the electric energy output by a plurality of wind generating sets is required to be collected and transmitted to the power grid for allocation by a power supply network. In some cases, voltage drops or other problems may occur at grid connection points between the wind turbine and the power grid, so that electric energy on the wind turbine side is accumulated, and the safety of the wind turbine is reduced.

The utility model provides a wind generating set, a wind farm and a wind power transmission system, wherein the wind generating set comprises a mechanical transmission structure, a generator, a machine side transformer, a modularized multi-level converter ((Modular Multilevel Converter, MMC), an alternating current-direct current converter (namely an AC/DC converter), a direct current-alternating current converter (namely a DC/AC converter), a set load and an unloading circuit, wherein the alternating current-direct current converter is electrically connected with the alternating current-direct current converter, the unloading circuit is electrically connected with the alternating current-direct current converter, and the unloading circuit can consume part of electric energy output by the generator under the condition that voltage drop occurs or other problems occur at a grid connection point between the wind generating set and a power grid, so that the risk caused by electric energy accumulation at the side of the wind generating set is avoided, the low voltage ride through capability of the wind generating set is improved, and the safety of the wind generating set and the stability at the side of the power grid of the system where the wind generating set is located are improved.

The wind generating set, the wind farm and the wind power transmission system provided by the utility model are respectively described below.

The first aspect of the utility model provides a wind power plant. Fig. 1 is a schematic structural diagram of a wind turbine generator system according to an embodiment of the present utility model, and fig. 2 is a schematic structural diagram of a wind turbine generator system according to another embodiment of the present utility model, where, as shown in fig. 1 and fig. 2, the wind turbine generator system may include a mechanical transmission structure 11, a generator 12, a machine side transformer 13, a modular multilevel converter 14, an ac-dc converter 15, a dc-ac converter 16, a unit load 17, and an unloading circuit 18.

The mechanical transmission 11 is connected to a generator 12. The mechanical transmission 11 may include blades 111 and a gearbox 112, where the blades 111 may convert wind energy into mechanical energy, which is converted into ac electrical energy by the generator 12 after being shifted through the gearbox 112.

The generator 12, the machine side transformer 13 and the modular multilevel converter 14 are electrically connected in sequence. The output end of the generator 12 is electrically connected with the input end of the machine side transformer 13, the output end of the machine side transformer 13 is electrically connected with the alternating current connection end of the modularized multi-level converter 14, and the direct current connection end of the modularized multi-level converter 14 can be regarded as the output end of the wind generating set. The ac power generated by the generator 12 may be transformed by a machine side transformer 13 and then input to a modular multilevel converter 14, which is converted to dc power output by the modular multilevel converter 14. In the embodiment of the utility model, the DC electric energy is output by the wind generating set, and the link of converting the DC electric energy into the AC electric energy in the wind generating set is omitted, so that the conversion efficiency and the transmission efficiency of the electric energy are improved. The wind generating set outputs direct-current electric energy, so that reactive charging current and overvoltage problems can be avoided in the electric energy collecting process of the wind generating set and the electric energy transmission process of the electric energy to the power grid, the loss of the electric energy output by the wind generating set in the electric energy transmission process is reduced, and the safety of the electric energy collecting process and the electric energy transmission process is improved.

Modular multilevel converter 14 may include three-phase leg units 21, each phase leg unit 21 may include two leg Sub-units connected in series, each leg Sub-unit may include more than one Sub-module (SM) 22 and one reactor L, the Sub-modules 22 in each leg Sub-unit, and the reactors L are connected in series. One of the bridge arm subunits in each phase bridge arm unit 21 is an upper bridge arm subunit 23, and the other bridge arm subunit in each phase bridge arm unit 21 is a lower bridge arm subunit 24. The reactor L of the upper arm subunit 23 is electrically connected to the reactor L of the lower arm subunit 24. In the case that the bridge arm sub-units comprise one sub-module 22, one end of the sub-module 22 of each upper bridge arm sub-unit 23 is electrically connected to the dc positive connection terminal of the modular multilevel converter 14, and one end of the sub-module 22 of each lower bridge arm sub-unit 24 is electrically connected to the dc negative connection terminal of the modular multilevel converter 14. In the case that the bridge arm sub-unit includes more than two sub-modules 22, one end of a first sub-module 22 of the sub-modules 22 connected in series in each upper bridge arm sub-unit 23 is electrically connected to the dc positive connection terminal of the modular multilevel converter 14, and one end of a last sub-module 22 of the sub-modules 22 connected in series in each lower bridge arm sub-unit 24 is electrically connected to the dc negative connection terminal of the modular multilevel converter 14. According to the embodiment of the utility model, the wind turbine generator set does not need to be expanded in parallel through the converters, the high-capacity requirement of the wind turbine generator set can be met through the combination of the plurality of sub-modules 22 in the modularized multi-level converter 14, the power density of the wind turbine generator set is improved, the structural complexity of the wind turbine generator set is reduced, and the volume of the wind turbine generator set is reduced.

The generator 12, the ac/dc converter 15, the dc/ac converter 16, and the unit load 17 are electrically connected in this order. The output end of the generator 12 is electrically connected to the ac connection end of the ac-dc converter 15, the dc connection end of the ac-dc converter 15 is electrically connected to the dc connection end of the dc-ac converter 16, and the ac connection end of the dc-ac converter 16 is electrically connected to the unit load 17. Part of the ac power generated by the generator 12 may be transmitted to the ac-dc converter 15, converted into dc power by the ac-dc converter 15, and converted into ac power by the dc-ac converter 16, and the ac power output by the dc-ac converter 16 may be transmitted to the unit load 17 to supply power to the unit load 17. In some examples, a transformer 19 may be disposed between the dc-ac converter 16 and the unit load 17, and the ac power output by the dc-ac converter 16 may be transformed by the transformer 19 and then transmitted to the unit load 17 to supply power to the unit load 17. Under the condition that the generator 12 of the wind generating set does not generate electric energy, the modularized multi-level converter 14 can be switched to an inversion mode, the direct current connection end of the modularized multi-level converter 14 obtains direct current electric energy from the outside, the direct current electric energy is converted into alternating current electric energy through the modularized multi-level converter 14, the alternating current electric energy is transmitted to the alternating current-direct current converter 15 through the machine side transformer 13, the alternating current electric energy is converted into direct current electric energy through the alternating current-direct current converter 15, the alternating current electric energy output by the direct current-alternating current converter 16 can be transmitted to the machine set load 17, and the machine set load 17 is supplied with power. Under the condition that the generator in the wind generating set does not generate electric energy, the wind generating set can also supply power to the set load 17, and the basic operation of the set load 17 is maintained.

The unloading circuit 18 is electrically connected with the ac-dc converter 15, and is used for consuming part of the electric energy output by the generator. In some examples, as shown in fig. 1, the unloading circuit 18 may be electrically connected to the output of the generator 12 and the ac connection of the ac-dc converter 15, and a portion of the electrical energy output by the generator 12 may be consumed by the unloading circuit 18, avoiding the risk of accumulating electrical energy on the wind turbine side. In other examples, the unloading circuit 18 may be electrically connected to the dc connection end of the ac-dc converter 15 and the dc connection end of the dc-ac converter 16, the electric energy output by the generator 12 may be converted by the ac-dc converter 15 and transmitted to the unloading circuit 18, and a part of the dc electric energy converted by the ac-dc converter 15 may be consumed by the unloading circuit 18, so as to avoid the risk caused by the accumulation of electric energy on the wind turbine generator set side.

In the embodiment of the utility model, the wind generating set comprises a mechanical transmission structure 11, a generator 12, a machine side transformer 13, a modularized multi-level converter 14, an alternating current-direct current converter 15, a direct current-alternating current converter 16, a set load 17 and an unloading circuit 18, wherein the mechanical transmission structure 11 is connected with the generator 12, the machine side transformer 13 and the modularized multi-level converter 14 are sequentially and electrically connected, the generator 12, the alternating current-direct current converter 15, the direct current-alternating current converter 16 and the set load 17 are sequentially and electrically connected, and the unloading circuit 18 is electrically connected with the alternating current-direct current converter 15. The unloading circuit 18 can consume part of the electric energy output by the generator under the condition that voltage drop occurs or other problems occur at the grid connection point between the wind generating set and the power grid, so that the risk caused by electric energy accumulation at the side of the wind generating set is avoided, the low voltage ride through capability of the wind generating set is improved, and the safety of the wind generating set and the power grid side stability of a system where the wind generating set is located are improved.

In some embodiments, the unloader circuit 18 may include a switching sub-circuit and an energy consuming sub-circuit in series. The switching sub-circuit is used to control the on and off of the unloader circuit 18, and may include a switching device by which the current through the energy consuming sub-circuit may be controlled to control the amount of electrical energy consumed by the unloader circuit 18. The power dissipating sub-circuit is configured to dissipate electrical power and may include a resistive device. The dc link of the ac-dc converter 15 in the above embodiment may include a first dc end and a second dc end, and the dc link of the dc-ac converter 16 may include a first dc end and a second dc end.

In some examples, a first end of the switching sub-circuit is electrically connected to a first dc end of ac-dc converter 15, a first dc end of dc-ac converter 16, a second end of the switching sub-circuit is electrically connected to a first end of the power dissipating sub-circuit, and a second end of the power dissipating sub-circuit is electrically connected to a second dc end of ac-dc converter 15, a second dc end of dc-ac converter 16. For ease of understanding, an embodiment of the unloading circuit is described herein, and fig. 3 is a schematic structural diagram of an example of the unloading circuit in fig. 2 provided by an embodiment of the present utility model, where, as shown in fig. 3, the switch sub-circuit may include a switch device K1, a first end of the switch device K1 is a first end of the switch sub-circuit, a second end of the switch device K1 is a second end of the switch sub-circuit, the energy dissipation sub-circuit may include a resistor device R1, a first end of the resistor device R1 is a first end of the energy dissipation sub-circuit, and a second end of the resistor device R1 is a second end of the energy dissipation sub-circuit; the first end of the switching device K1 is electrically connected to the first dc end of the ac-dc converter 15 and the first dc end of the dc-ac converter 16, the second end of the switching device K2 is electrically connected to the first end of the resistor device R1, and the second end of the resistor device R1 is electrically connected to the second dc end of the ac-dc converter 15 and the second dc end of the dc-ac converter 16.

In other examples, the unloading circuit may further include a rectifier sub-circuit. The rectifier sub-circuit is connected in parallel with the switching sub-circuit and the energy consuming sub-circuit connected in series. The commutator circuit has three-phase alternating current terminals and direct current terminals, the three-phase alternating current terminals may include a first-phase alternating current terminal, a second-phase alternating current terminal, and a third-phase alternating current terminal, and the direct current terminals may include a first direct current terminal and a second direct current terminal. The three-phase ac end of the rectifier circuit is electrically connected with the output end of the generator 12 and the three-phase ac end of the ac-dc converter 15, the first dc end of the rectifier circuit is electrically connected with the first end of the switch sub-circuit, the second end of the switch sub-circuit is electrically connected with the first end of the energy dissipation sub-circuit, and the second end of the energy dissipation sub-circuit is electrically connected with the second dc end of the rectifier sub-circuit. The rectifier sub-circuit comprises three-phase diode bridge arms, each phase diode bridge arm comprises a first upper bridge arm unit and a first lower bridge arm unit, the first upper bridge arm unit comprises at least one diode, and the first lower bridge arm unit comprises at least one diode. For ease of understanding, another specific example of the unloading circuit is described herein, and fig. 4 is a schematic structural diagram of an example of the unloading circuit in fig. 1 provided by an embodiment of the present utility model, where, as shown in fig. 4, the switch sub-circuit includes a switch device K2, a first end of the switch device K2 is a first end of the switch sub-circuit, and a second end of the switch device K2 is a second end of the switch sub-circuit; the energy consumption sub-circuit comprises a resistor device R2, wherein the first end of the resistor device R2 is the first end of the energy consumption sub-circuit, and the second end of the resistor device R2 is the second end of the energy consumption sub-circuit; the first upper bridge arm unit comprises a diode, the first lower bridge arm unit comprises a diode, the first upper bridge arm unit in the first phase diode bridge arm comprises a diode D1, the first lower bridge arm unit in the first phase diode bridge arm comprises a diode D4, the first upper bridge arm unit in the second phase diode bridge arm comprises a diode D2, the first lower bridge arm unit in the second phase diode bridge arm comprises a diode D5, the first upper bridge arm unit in the third phase diode bridge arm comprises a diode D3, the first lower bridge arm unit in the third phase diode bridge arm comprises a diode D6, the anode of the diode D1 and the cathode of the diode D4 are electrically connected with a first phase alternating current end in a three-phase alternating current end of a rectifier circuit, the anode of the diode D2 and the cathode of the diode D5 are electrically connected with a second phase alternating current end in a three-phase alternating current end of a rectifier circuit, the anode of the diode D3 and the cathode of the diode D6 are electrically connected with a third phase alternating current end in a three-phase end in a rectifier circuit, and the cathode of the diode D2 and the cathode of the diode D4 and the anode of the diode D4 are electrically connected with the second phase alternating current end in a direct current end in a rectifier circuit; the first end of the switching device K2 is electrically connected to the cathode of the diode D1, the cathode of the diode D2, and the cathode of the diode D3, the second end of the switching device K2 is electrically connected to the first end of the resistor device R2, and the second end of the resistor device R2 is electrically connected to the anode of the diode D4, the anode of the diode D5, and the anode of the diode D6.

In some embodiments, the wind generating set may further include an energy storage unit, where the energy storage unit is used to store electric energy and release electric energy, and the energy storage unit may include a storage battery, a flywheel, and other devices, which are not limited herein. Fig. 5 is a schematic structural diagram of a wind turbine generator according to another embodiment of the present utility model, and fig. 6 is a schematic structural diagram of a wind turbine generator according to another embodiment of the present utility model, as shown in fig. 5 and 6, the energy storage unit 25 may be electrically connected to the first dc end of the ac-dc converter 15, the first dc end of the dc-ac converter 16, the second dc end of the ac-dc converter 15, and the second dc end of the dc-ac converter 16.

In case that the generator 12 does not generate electric energy, for example, the wind power generator set is in a shutdown state, the energy storage unit 25 may release pre-stored electric energy, convert the electric energy released by the energy storage unit 25 into ac electric energy through the dc-ac converter 16, and transmit the ac electric energy to the set load 17 through the transformer 19 to supply power to the set load 17. Because the capacity of the energy storage unit 25 is limited, the requirement of the unit load 17 under the condition that the generator 12 does not generate electric energy for a long time can not be met, the modular multilevel converter 14 can be switched to a rectification mode, the electric energy is obtained from the outside through the direct current connecting end of the modular multilevel converter 14, the obtained direct current electric energy is converted into alternating current electric energy, the alternating current electric energy is transmitted to the alternating current-direct current converter 15 through the machine side transformer 13, and the alternating current-direct current electric energy is converted into direct current electric energy through the alternating current-direct current converter 15, so that the energy storage unit 25 is charged. After the energy storage unit 25 is fully charged, the dc power converted by the ac-dc converter 15 may only supply the unit load.

In the case where the generator 12 generates electric power, such as when the wind turbine is in operation, a portion of the electric power generated by the generator 12 is transmitted to the ac-dc converter 15, and is converted into dc electric power by the ac-dc converter 15, thereby charging the energy storage unit 25. After the energy storage unit 25 is fully charged, the dc power converted by the ac-dc converter 15 may only supply the unit load.

In some examples, the electrical energy capacity of ac-dc converter 15 is equal to or greater than the sum of the electrical energy capacity of energy storage unit 25 and the electrical energy demand of unit load 17.

The unit load in the above embodiment may include one or more of a unit control unit, a unit ring control unit, a control unit of the modular multilevel converter 14, and the like, but is not limited thereto.

A second aspect of the utility model provides a wind farm. Fig. 7 is a schematic structural diagram of a wind farm according to an embodiment of the present utility model, and fig. 8 is a schematic structural diagram of a wind farm according to another embodiment of the present utility model, where, as shown in fig. 7 and fig. 8, the wind farm includes at least one group of wind turbine generator sets, and each group of wind turbine generator sets includes more than two wind turbine generator sets in the above embodiments. Wherein, the power supply receiving ends of the unit loads 17 in the same group of wind generating units are connected in parallel. In each wind power generator set, the power supply receiving end of the set load 17 is electrically connected with the ac connection end of the dc-ac converter 16. The number of wind turbine generators in different groups may be the same or different, and is not limited herein. In some examples, to avoid overcomplicating wind farm 20 structures, each group may include 3 to 6 wind turbine generator sets.

The power supply ends of the unit loads 17 are connected in parallel, so that other wind power generator sets can supply power to the unit loads 17 under the condition that one or a plurality of wind power generator sets cannot supply power to the unit loads 17. That is, the wind power generator sets with the power supply ends of the set loads 17 connected in parallel can supply power to each other set load 17 when needed, so as to further improve the stability of the set load power supply of the wind power generator set.

In some examples, the dc connections of the modular multilevel converters in at least part of the wind power plants are connected in series. For example, fig. 9 is a schematic structural diagram of a wind farm according to another embodiment of the present utility model, where, as shown in fig. 9, the wind farm includes N wind generating sets with dc connection ends of the modular multilevel converters 14 connected in series, N is an integer greater than or equal to 2, and in the wind generating sets with the dc connection ends of the N modular multilevel converters 14 connected in series, a first dc connection end of the modular multilevel converter 14 of a first wind generating set may be used as a first output end of the wind farm, a second dc connection end of the modular multilevel converter 14 of an nth wind generating set may be used as a second output end of the wind farm, and a second dc connection end of the modular multilevel converter 14 of an ith wind generating set is electrically connected with a first dc connection end of the modular multilevel converter 14 of the i+1th wind generating set, where i is an integer and 1 is less than or equal to N.

A third aspect of the utility model provides a wind power transmission system. Fig. 10 is a schematic structural diagram of a wind power transmission system according to an embodiment of the present utility model, and as shown in fig. 10, the wind power transmission system may include a wind farm 31, a dc booster 32, a grid-side converter 33, a grid-side transformer 34, and a grid 35 electrically connected in sequence.

The output of the wind farm 31 is electrically connected to the input of the dc booster 32, the output of the dc booster 32 is electrically connected to the input of the grid-side converter 33, the output of the grid-side converter 33 is electrically connected to the input of the grid-side transformer 34, and the output of the grid-side transformer 34 is electrically connected to the grid 35. In the case that the wind farm 31 includes more than two wind generating sets 311, the output ends of the wind generating sets 311 in the wind farm 31 may be connected in series, and details of the connection of the output ends of the wind generating sets 311 in the wind farm 31 in series may be referred to the above description of the wind farm 31, which is not repeated herein.

The dc power output by the wind generating set of the wind farm 31 may be collected and transmitted to the dc booster 32, the dc booster 32 may boost the dc power, the dc booster 32 may be electrically connected to the grid-side converter 33 through a dc power transmission line, the dc power boosted by the dc booster 32 may be transmitted to the grid-side converter 33 through the dc power transmission line, the grid-side converter 33 converts the boosted dc power into ac power and transmits the ac power to the grid-side transformer 34, and the grid-side transformer 34 transforms the ac power into ac power meeting the grid requirements and transmits the ac power to the grid 35.

The wind power generation and transmission system in the above embodiment is applicable to offshore wind power generation and also applicable to onshore wind power generation, and is not limited thereto. If the wind power generation and transmission system in the above embodiment is applied to offshore wind power generation, the wind farm 31 may be an offshore wind farm, the dc booster 32 may be implemented as an offshore dc booster station, the grid-side converter 33 may be implemented as an onshore converter station, and the grid-side transformer 34 may be implemented as an onshore transformer station.

In some examples, dc boost 32 may comprise a dc chopper type converter, grid-side converter 33 may comprise a modular multilevel converter, and grid-side transformer 34 may comprise an ac transformer, but is not limited thereto and is not listed herein.

It should be understood that, in the present specification, each embodiment is described in an incremental manner, and the same or similar parts between the embodiments are all referred to each other, and each embodiment is mainly described in a different point from other embodiments. For wind farm embodiments, wind power transmission system embodiments, the relevant points may be found in the description of wind turbine generator set embodiments. The utility model is not limited to the specific constructions described above and shown in the drawings. Various changes, modifications and additions may be made by those skilled in the art after appreciating the spirit of the present utility model. Also, a detailed description of known techniques is omitted herein for the sake of brevity.

Those skilled in the art will appreciate that the above-described embodiments are exemplary and not limiting. The different technical features presented in the different embodiments may be combined to advantage. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in view of the drawings, the description, and the claims. In the claims, the term "comprising" does not exclude other means or steps; the word "a" does not exclude a plurality; the terms "first," "second," and the like, are used for designating a name and not for indicating any particular order. Any reference signs in the claims shall not be construed as limiting the scope. The functions of the various elements presented in the claims may be implemented by means of a single hardware or software module. The presence of certain features in different dependent claims does not imply that these features cannot be combined to advantage.

Claims (10)

1. The wind generating set is characterized by comprising a mechanical transmission structure, a generator, a machine side transformer, a modularized multi-level converter, an alternating current-direct current converter, a direct current-alternating current converter, a set load and an unloading circuit;

wherein the mechanical transmission structure is connected with the generator, the machine side transformer and the modularized multi-level converter are sequentially and electrically connected, the generator, the AC-DC converter, the DC-AC converter and the unit load are sequentially and electrically connected, the unloading circuit is electrically connected with the AC-DC converter,

the unloading circuit is used for consuming part of the electric energy output by the generator.

2. The wind power generator set of claim 1, wherein the unloading circuit comprises a switching sub-circuit and an energy consuming sub-circuit in series,

wherein the switching sub-circuit comprises a switching device and the energy consuming sub-circuit comprises a resistive device.

3. A wind turbine generator set according to claim 2, wherein the wind turbine generator set comprises,

the first end of the switch sub-circuit is electrically connected with the first direct current end of the alternating current-direct current converter and the first direct current end of the direct current-alternating current converter, the second end of the switch sub-circuit is electrically connected with the first end of the energy dissipation sub-circuit, and the second end of the energy dissipation sub-circuit is electrically connected with the second direct current end of the alternating current-direct current converter and the second direct current end of the direct current-alternating current converter.

4. A wind turbine generator set according to claim 2, wherein the wind turbine generator set comprises,

the unloading circuit further comprises a rectifier sub-circuit,

the rectifier sub-circuit is connected with the switch sub-circuit and the energy dissipation sub-circuit which are connected in series in parallel, the three-phase alternating-current end of the rectifier sub-circuit is electrically connected with the output end of the generator and the three-phase alternating-current end of the alternating-current direct-current converter, the first direct-current end of the rectifier sub-circuit is electrically connected with the first end of the switch sub-circuit, the second end of the switch sub-circuit is electrically connected with the first end of the energy dissipation sub-circuit, and the second end of the energy dissipation sub-circuit is electrically connected with the second direct-current end of the rectifier sub-circuit.

5. A wind turbine generator set according to claim 4, wherein the wind turbine generator set comprises,

the rectifier sub-circuit comprises three-phase diode bridge arms, each phase diode bridge arm comprises a first upper bridge arm unit and a first lower bridge arm unit, the first upper bridge arm unit comprises at least one diode, and the first lower bridge arm unit comprises at least one diode.

6. The wind power generator set of claim 1, further comprising an energy storage unit electrically connected to the first dc end of the ac-dc converter, the first dc end of the dc-ac converter, the second dc end of the ac-dc converter, and the second dc end of the dc-ac converter, the energy storage unit configured to store electrical energy and release electrical energy.

7. The wind power generator set of claim 1, wherein the set load comprises one or more of:

the control unit comprises a unit control unit, a unit ring control unit and a control unit of the modularized multi-level converter.

8. A wind farm comprising at least one group of wind power plants, each group comprising more than two wind power plants according to any of claims 1 to 7,

and the power supply receiving ends of the unit loads in the same group of wind generating units are connected in parallel.

9. A wind farm according to claim 8, wherein,

the direct current connection ends of the modular multilevel converters in at least part of the wind generating sets in the wind power plant are connected in series.

10. A wind power transmission system comprising a wind farm, a dc booster, a grid-side converter, a grid-side transformer and a grid according to claim 8 or 9 electrically connected in sequence.