CN116316859A

CN116316859A - Wind generating set, control method and device thereof, and computer readable storage medium

Info

Publication number: CN116316859A
Application number: CN202310552920.3A
Authority: CN
Inventors: 李昂; 艾斯卡尔
Original assignee: Beijing Goldwind Science and Creation Windpower Equipment Co Ltd
Current assignee: Beijing Goldwind Science and Creation Windpower Equipment Co Ltd
Priority date: 2023-05-17
Filing date: 2023-05-17
Publication date: 2023-06-23

Abstract

The present disclosure provides a wind turbine generator system, a control method, a control device, and a computer-readable storage medium thereof, the wind turbine generator system including: a generator; the rotor loop is connected between the rotor of the generator and the grid-connected point; a short-circuit switch connected between the rotor of the generator and the short-circuit point; and the stator loop is connected between the stator of the generator and the grid connection point and comprises a full-power converter, a stator switch and a bypass switch, wherein the full-power converter and the stator switch are connected in series and then connected with the bypass switch in parallel. The rotor loop can be withdrawn from grid connection by closing the short circuit switch, the stator switch and the bypass switch at low wind speed, and the stator loop with the full-power converter is independently connected. At the moment, as the rotor loop exits, the full-power converter is not affected by slip, so that the rotating speed of the impeller can be reduced to reduce the tip speed ratio, and the optimal tip speed ratio is realized, thereby improving wind power capture and improving the power generation efficiency of the doubly-fed machine set in light load.

Description

Wind generating set, control method and device thereof, and computer readable storage medium

Technical Field

The present disclosure relates to the field of wind power generation, and more particularly, to a wind turbine generator set, a control method, a control device, and a computer-readable storage medium thereof.

Background

At present, two main technical routes exist for the grid-connected wind generating set, one is a direct-driven wind generating set, a permanent magnet synchronous generator is adopted to convert electric energy, the other is a doubly-fed wind generating set, an asynchronous generator is adopted to convert electric energy, and a stator loop and a rotor loop of the asynchronous generator are directly or indirectly connected to a power grid to realize double-end feeding, namely the asynchronous generator is specifically a doubly-fed asynchronous generator. As shown in FIG. 1, a traditional doubly-fed wind turbine generator set is characterized in that an impeller 1 'drives a gear box 2', so that the conversion of wind energy to mechanical energy is realized; the gear box 2 'drives the asynchronous generator 3' and realizes the conversion of mechanical energy to electric energy; the stator side of the asynchronous generator 3 'is boosted by a booster transformer 4' and is integrated on the internal feed line of the wind power plant; the rotor-side electric energy of the asynchronous generator 3 'is converted and boosted by the machine-side converter 5', the grid-side converter 6 'and the booster transformer 4', respectively, and finally is converged on the internal feed line of the wind power plant. In fig. 1, the operating frequency is 50Hz, both on the high-voltage side and on the low-voltage side of the converter; the high-voltage side of the step-up transformer 4' is generally 35kV, and the low-voltage side voltage level varies according to the model, and 690V is generally selected to be the most. In view of this, the doubly-fed wind turbine generator set shown in fig. 1 may also be referred to as a low-voltage power-frequency doubly-fed asynchronous wind turbine generator set. The double-fed wind generating set has the advantages that constant-frequency power generation can be realized at different rotating speeds, and the requirements of power load and grid connection are met.

The tip speed ratio is an important performance index of the wind generating set, and refers to the ratio of the tip linear speed to the wind speed of a wind wheel blade, and the longer the blade or the faster the wind wheel rotating speed, the larger the tip speed ratio at the same wind speed. In order to increase the generating capacity of the unit, the blade tip speed ratio needs to be reduced. For a doubly-fed wind turbine generator set, in order to operate the wind turbine at the optimal tip speed ratio at low wind speeds, the wind turbine rotational speed needs to be reduced along with the reduction of wind speed, so that slip (the difference between the rotational speed of a stator rotating magnetic field and the rotational speed of a rotor of an asynchronous generator) is too large, and the excessive slip can cause the excessive rotor voltage to exceed the safe working range of a machine side converter because the rotor voltage is in direct proportion to the slip. Therefore, in order to ensure the safety of the machine side converter, the optimal tip speed ratio of the wind wheel must be abandoned, namely, the optimal wind power capture is abandoned, so that the power generation efficiency of the doubly-fed machine set is far lower than that of the direct-drive machine set in light load.

Disclosure of Invention

Therefore, how to improve the power generation efficiency of the doubly-fed wind turbine generator system in light load is of great importance.

In one general aspect, there is provided a wind power generation set including: a generator; a rotor loop connected between the rotor of the generator and a grid connection point; a short circuit switch connected between the rotor of the generator and a short circuit point; and the stator loop is connected between the stator of the generator and the grid connection point and comprises a full-power converter, a stator switch and a bypass switch, wherein the full-power converter and the stator switch are connected in series and then connected with the bypass switch in parallel.

Optionally, the stator output voltage of the generator is matched with the voltage of the power grid into which the wind generating set is incorporated; the wind power generator set further comprises a step-up transformer arranged in the rotor loop.

Optionally, the capacity of the step-up transformer ranges from 20% to 35% of the capacity of the wind generating set.

Optionally, the full power converter includes at least one of: modularized multi-level converter and modularized multi-level matrix converter.

Optionally, the submodule of the full-power converter includes at least one of: half-bridge submodule, full-bridge submodule, clamp double submodule, five-switch submodule and half-bridge submodule combined by four capacitors.

Optionally, the rotor loop includes a rotor side switch, a rotor converter and a rotor net side switch connected in series in order, one end of the rotor side switch is connected between the rotor of the generator and the short-circuit switch, and the other end of the rotor side switch is connected with the rotor converter.

Optionally, the wind generating set further comprises a grid-connected switch, one end of the grid-connected switch is connected to the grid-side end of the rotor loop and the grid-side end of the stator loop at the same time, and the other end of the grid-connected switch is connected to the grid-connected point.

In another general aspect, there is provided a control method of a wind turbine generator set, where the wind turbine generator set is any one of the wind turbine generator sets described above, the control method including: obtaining the output power of the wind generating set; in response to determining that the output power is less than or equal to a preset power, controlling the short-circuit switch and the stator switch to be closed and controlling the bypass switch to be opened; and in response to determining that the output power is greater than the preset power, controlling the short-circuit switch and the stator switch to be opened and controlling the bypass switch to be closed.

Optionally, the preset power is equal to the product of the rated power of the wind generating set and a preset duty ratio, and the value range of the preset duty ratio is 15% to 30%.

In another general aspect, there is provided a control device for a wind turbine generator set, the wind turbine generator set being any one of the wind turbine generator sets described above, the control device comprising: an acquisition unit configured to acquire output power of the wind generating set; a control unit configured to control the short-circuit switch and the stator switch to be closed and the bypass switch to be opened in response to determining that the output power is less than or equal to a preset power; the control unit is further configured to control the short-circuit switch and the stator switch to open and the bypass switch to close in response to determining that the output power is greater than the preset power.

In another general aspect, there is provided a computer-readable storage medium, which when executed by at least one processor, causes the at least one processor to perform a method of controlling a wind turbine generator set as described above.

In another general aspect, there is provided a computer device comprising: at least one processor; at least one memory storing computer-executable instructions, wherein the computer-executable instructions, when executed by the at least one processor, cause the at least one processor to perform a method of controlling a wind turbine generator set as described above.

The present disclosure provides a wind generating set, a control method, an apparatus, and a computer readable storage medium thereof, where by setting a short circuit switch, a bypass switch, and a full power converter, the bypass switch is turned on (in practice, the switch on the rotor loop is also turned off) by closing the short circuit switch and the stator switch at low wind speed, so that the rotor loop exits from grid connection, and the stator loop with the full power converter is individually connected to a power grid through a grid connection point, so that the generator does not operate as a doubly-fed asynchronous generator, but is converted into a normal asynchronous generator operation (i.e. only stator side single-ended feeding), and the full power converter is used to realize the current conversion of the stator side circuit (the rotor current on the rotor loop can be regulated by the rotor converter when the rotor loop is connected, thereby realizing the current conversion of the stator side circuit). At the moment, the rotor loop exits, and the full-power converter is not affected by slip, so that the rotating speed of the impeller can be reduced to realize the optimal tip speed ratio, thereby improving wind power capture and improving the power generation efficiency of the doubly-fed machine set in light load. The scheme can reduce the cut-in rotating speed of the wind generating set and improve the speed change range of the double-fed generator set, thereby comprehensively improving the generated energy.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The above and other objects and features of the present disclosure will become more apparent from the following description of the embodiments taken in conjunction with the accompanying drawings in which:

FIG. 1 is a topology diagram showing a doubly-fed asynchronous wind turbine generator set in the related art;

FIG. 2 is a topology diagram illustrating a wind turbine generator set according to one embodiment of the present disclosure;

FIG. 3 is a topology diagram illustrating a wind turbine generator system according to another embodiment of the present disclosure;

fig. 4 to 8 are sub-module topologies showing a full power converter according to an embodiment of the present disclosure;

FIG. 9 is a flowchart illustrating a method of controlling a wind turbine generator set according to an embodiment of the present disclosure;

FIG. 10 is a block diagram illustrating a control device of a wind turbine according to an embodiment of the present disclosure;

fig. 11 is a block diagram illustrating a computer device according to an embodiment of the present disclosure.

Figure 1 reference numerals illustrate:

1': an impeller; 2': a gear box; 3': an asynchronous generator; 4': a step-up transformer; 5': a machine side converter; 6': a grid-side converter;

Fig. 2 and 3 reference numerals illustrate:

10: a generator;

20: a rotor circuit; 21: a rotor side switch; 22: a rotor converter; 221: a rotor-side converter; 222: a rotor mesh side converter; 23: a rotor mesh side switch;

30: a short-circuit switch;

40: a stator circuit; 41: a full power converter; 411: a machine side converter; 412: a grid-side converter; 413: an energy consumption circuit; 4131: an energy consumption resistor; 4132: an energy consumption switch; 42: a stator switch; 43: a bypass switch; 44: a charging circuit; 441: a charging resistor; 442: a charging switch;

50: a gear box;

60: an impeller;

70: a step-up transformer;

80: a grid-connected switch;

a: a grid-connected point;

b: short circuit point.

Detailed Description

The following detailed description is provided to assist the reader in obtaining a thorough understanding of the methods, apparatus, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent after an understanding of the disclosure of the present application. For example, the order of operations described herein is merely an example and is not limited to those set forth herein, but may be altered as will be apparent after an understanding of the disclosure of the present application, except for operations that must occur in a particular order. Furthermore, descriptions of features known in the art may be omitted for clarity and conciseness.

The features described herein may be embodied in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein have been provided to illustrate only some of the many possible ways to implement the methods, devices, and/or systems described herein, which will be apparent after an understanding of the present disclosure.

As used herein, the term "and/or" includes any one of the listed items associated as well as any combination of any two or more.

Although terms such as "first," "second," and "third" may be used herein to describe various elements, components, regions, layers or sections, these elements, components, regions, layers or sections should not be limited by these terms. Rather, these terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first member, first component, first region, first layer, or first portion referred to in the examples described herein may also be referred to as a second member, second component, second region, second layer, or second portion without departing from the teachings of the examples.

In the description, when an element (such as a layer, region or substrate) is referred to as being "on" another element, "connected to" or "coupled to" the other element, it can be directly "on" the other element, be directly "connected to" or be "coupled to" the other element, or one or more other elements intervening elements may be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" or "directly coupled to" another element, there may be no other element intervening elements present.

The terminology used herein is for the purpose of describing various examples only and is not intended to be limiting of the disclosure. Singular forms also are intended to include plural forms unless the context clearly indicates otherwise. The terms "comprises," "comprising," and "having" specify the presence of stated features, amounts, operations, components, elements, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, amounts, operations, components, elements, and/or combinations thereof.

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs after understanding this disclosure. Unless explicitly so defined herein, terms (such as those defined in a general dictionary) should be construed to have meanings consistent with their meanings in the context of the relevant art and the present disclosure, and should not be interpreted idealized or overly formal.

In addition, in the description of the examples, when it is considered that detailed descriptions of well-known related structures or functions will cause a ambiguous explanation of the present disclosure, such detailed descriptions will be omitted.

The wind power generation set provided by the embodiment of the present disclosure will be described below with reference to fig. 2 to 4.

As shown in fig. 2, an embodiment of an aspect of the present disclosure provides a wind power generator set including a generator 10, a rotor circuit 20, a shorting switch 30, and a stator circuit 40.

The generator 10 is in particular an asynchronous generator. As with the prior art units, the generator 10 is also preceded by a gearbox 50 and impeller 60.

The rotor loop 20 is connected between the rotor of the generator 10 and a grid connection point a, which can be directly connected to the grid or can be connected to a feeder inside the wind farm. The rotor circuit 20 includes a rotor-side switch 21, a rotor converter 22, and a rotor net-side switch 23 connected in series in this order, and the rotor converter 22 is capable of converting current of the rotor-side circuit, compensating for a difference between a mechanical frequency and an electrical frequency, and effectively managing an operation state of the generator 10. As shown in fig. 3, the rotor converter 22 may be a conventional doubly-fed converter, specifically including a rotor-side converter 221 and a rotor grid-side converter 222, which are controlled independently of each other, the rotor-side converter 221 may control active power and reactive power by controlling a rotor current component, and the rotor grid-side converter 222 may control a dc bus voltage and ensure that the rotor converter 22 operates at a uniform power factor. By providing the rotor-side switch 21 between the rotor-side current transformer 221 and the rotor of the generator 10 and providing the rotor-net-side switch 23 on the side of the rotor-net-side current transformer 222 remote from the rotor-side current transformer 221, independent switching control of the rotor-side current transformer 221 and the rotor-net-side current transformer 222 can be achieved, and reliable operation of the rotor current transformer 22 is ensured.

The short-circuit switch 30 is connected between the rotor of the generator 10 and the short-circuit point B, and one end of the short-circuit switch 30 connected to the rotor of the generator 10 is specifically connected between the rotor of the generator 10 and the rotor-side switch 21 of the rotor circuit 20, so that one end of the rotor-side switch 21 is connected between the rotor of the generator 10 and the short-circuit switch 30, and the other end is connected to the rotor converter 22. When the shorting switch 30 is closed, the rotor circuit 20 may be taken out of grid connection due to shorting.

The stator circuit 40 is connected between the stator of the generator 10 and the grid connection point a, and the stator circuit 40 includes a full power converter 41, a stator switch 42 and a bypass switch 43, wherein the full power converter 41 and the stator switch 42 are connected in series and then connected in parallel with the bypass switch 43. By adding the bypass switch 43 and the full-power converter 41 on the basis of the existing stator loop, the generator 10 can be converted into a common asynchronous generator operation (namely, only stator side single-ended feed) without being operated as a doubly-fed asynchronous generator by adding the bypass switch 43 and the full-power converter 41 to the existing stator loop, and converting the stator side circuit into a current by closing the short-circuit switch 30 and the stator switch 42 and opening the bypass switch 43 (in practice, opening the rotor side switch 21 and the rotor net side switch 23 on the rotor loop 20) when the wind speed is low, so that the rotor loop 20 is out of grid connection, and the rotor side circuit is converted into a current by independently connecting the stator loop 40 with the full-power converter 41 to the grid through the grid connection point A. At this time, the rotor loop 20 exits, and the full-power converter 41 is not affected by slip, so that the rotation speed of the impeller 60 can be reduced to realize an optimal tip speed ratio, thereby improving wind power capture and improving the power generation efficiency of the doubly-fed machine set in light load. The scheme can reduce the cut-in rotating speed of the wind generating set and improve the speed change range of the double-fed generator set, thereby comprehensively improving the generated energy.

Optionally, unlike the stator output voltage of the existing doubly-fed machine set, which is usually 690V or 1140V, the stator output voltage of the generator 10 of the present disclosure is matched with the voltage of the power grid in which the wind power generator set is incorporated, for example, when the power grid voltage is 35kV, the stator output voltage is also 35kV, and when the power grid voltage is 10kV, the stator output voltage is also 10kV, so that the stator of the generator 10 directly outputs medium voltage, and at this time, the stator loop 40 does not need to be connected with the step-up transformer 70, which can reduce a primary power conversion link and help to further improve the power generation efficiency. Meanwhile, the step-up transformer 70 of the wind generating set is arranged in the rotor loop 20, and can step up the voltage levels of 690V, 1140V and the like to 35kV or 10kV medium voltage, and the step-up transformer 70 is only used for step-up on the rotor side, so that the capacity and the volume of the step-up transformer 70 can be greatly reduced, the installation space is saved, the bearing cost of the layout position of the step-up transformer 70 can be reduced, the corresponding cost is further reduced, and the economy of the whole wind generating set is improved. As an example, the nacelle load-bearing costs may be reduced for the case of laying up the step-up transformer 70 in the nacelle of the unit, and the tower load-bearing costs may be reduced for the case of laying up the step-up transformer 70 in the tower bottom.

Further, in the case where the stator of the generator 10 directly outputs medium voltage and the step-up transformer 70 is provided in the rotor circuit 20, the capacity of the step-up transformer 70 is valued in the range of 20% to 35% of the capacity of the wind turbine generator set. Since the rotor output power is typically about 20% to 25% of the total power, the capacity of the step-up transformer 70 may be reduced by at least 70% relative to existing structures. In addition, to ensure use safety, the capacity of the existing step-up transformer often remains partially redundant based on the capacity of the wind generating set, for example, for a wind generating set with a capacity of 6MW, a step-up transformer with a capacity of 7MW is often adopted, and thus, the capacity of the step-up transformer 70 may be slightly higher than 20% to 25% of the capacity of the wind generating set. The capacity of the step-up transformer 70 is specifically configured to be 20-35% of the capacity of the wind generating set, so that the step-up requirement of a rotor side can be met, the reliable operation of the set is ensured, the capacity and the volume of the step-up transformer 70 can be greatly reduced, and the economy of the whole machine is improved. Specifically, the capacity value of step-up transformer 70 may be configured according to the actual duty cycle of the rotor output power in the capacity of the wind turbine.

Optionally, the full power converter 41 comprises at least one of: a modularized multi-level converter (Modular Multilevel Converter, abbreviated as MMC) and a modularized multi-level matrix converter (Modular Multilevel Matrix Converter, abbreviated as M3C). Through selecting the multi-level converter of modularization or the multi-level matrix converter of modularization, can make stator side direct output middling pressure, satisfy stator output voltage's value demand to voltage is high, the current stress is little, the loss is little this moment, helps fully promoting generating efficiency. It should be appreciated that for embodiments where the stator of the generator 10 outputs a low voltage, the full power converter 41 may be a conventional low voltage output converter, in which case the boost transformer 70 may be positioned with reference to the existing structure, i.e., with reference to fig. 1, while connecting the grid-side end of the stator circuit 40 and the grid-side end of the rotor circuit 20.

Further, as shown in fig. 3, the full-power converter 41 includes a machine side converter 411 and a grid side converter 412 connected in series, the machine side converter 411 is used for converting ac power into dc power, and the grid side converter 412 is used for transmitting the power generated by the generator 10 to the grid connection point a after converting the dc power into the ac power. As an example, as shown in fig. 3, the side converter 411 and the network side converter 412 are both modularized multi-level converters, and each phase has an upper and a lower two bridge arms, and each bridge arm is formed by connecting N Sub Modules (SM) and a bridge arm reactor Larm in series.

Optionally, the submodules of the full power converter 41 include at least one of: half-bridge submodules (see fig. 4), full-bridge submodules (see fig. 5), clamp double submodules (see fig. 6), five-switch submodules (see fig. 7), and four-capacitor combined half-bridge submodules (see fig. 8). By configuring various topologies for the submodules of the full-power converter 41, proper submodule topologies can be selected according to the requirements of specific application scenes by comprehensively considering the economy, the volume and the control complexity of the device, so that the design flexibility is improved, and the generating efficiency of a unit is improved. Besides the half-bridge submodules, other submodules can realize fault self-clearing.

Further, the full power converter 41 further comprises a power dissipation circuit 413 coupled between the machine side converter 411 and the grid side converter 412, the power dissipation circuit 413 comprising a power dissipation resistor 4131 and a power dissipation switch 4132 connected in series. By providing the energy consumption circuit 413, it is possible to consume electric energy by heat generation of the energy consumption resistor 4131 when electric energy generated by the generator 10 cannot be transmitted to the grid-connected point a, so as not to damage the side converter 411 and the grid-side converter 412. Specifically, if the grid-side converter 412 fails, the electric energy may be transferred to the energy dissipation resistor 4131 through the grid-side converter 411; if the machine side converter 411 fails, the freewheeling diode within the machine side converter 411 may transfer energy to the dissipation resistor 4131 to dissipate. Therefore, it should be understood that the energy dissipation resistor 4131 has a large capacity or current to meet the power consumption requirement, and no requirement is imposed on the resistor.

Optionally, the stator loop 40 further comprises a charging circuit 44, the charging circuit 44 is connected in parallel with the stator switch 42, i.e. after the full power converter 41 is connected in series with the parallel connected stator switch 42 and the charging circuit 44, is connected in parallel with the bypass switch 43, and the charging circuit 44 comprises a charging resistor 441 and a charging switch 442 connected in series. The charging circuit 44 is connected in parallel to the stator switch 42, so that the charging circuit and the stator switch 42 can be matched, and the charging resistor 441 is connected into the stator loop 40 by closing the charging switch 442 and opening the stator switch 42 in a starting state, so that the current on the stator loop 40 is reduced when the unit is started, the initial voltage is softly provided for the full-power converter 41, and the risks of generating impact current and damaging internal components of the full-power converter 41 when the full-power converter 41 is directly connected with the grid-connected point A are reduced. After the charging is completed, the charging switch 442 is opened, the stator switch 42 is closed, and the charging resistor 441 is withdrawn from the stator loop 40, so that the full-power converter 41 enters a normal working state. In addition, by connecting the charging switch 442 and the charging resistor 441 in parallel with the stator switch 42, instead of connecting the charging resistor 441 in parallel with the stator switch 42 and then connecting the charging switch 442 in series, the charging switch 442 can be only used for controlling the on-off of the charging circuit 44, the current passing through the charging switch 442 in the charging process is smaller, and the charging switch 442 is disconnected after the charging is completed, and the large current on the stator loop 40 cannot pass through the charging switch 442, so that the charging switch 442 can be a small-capacity switch, thereby contributing to reducing the hardware cost. The stator switch 42 needs to be a high-capacity switch to ensure reliable implementation of the switching function of the stator circuit 40. In practice, determining whether charging is completed may be accomplished by detecting whether the voltage charged by the full power converter 41 is sufficient, and after determining that charging is completed, the charging switch 442 may be opened, the charging process is completed so far, and the stator switch 42 may be closed in response to the charging process being completed, so that the control process is simple and efficient. It should be appreciated that the charging resistor 441 needs to have a high resistance to meet the buffering requirement, and no requirement is made for capacity. As an example, as the rotor converter 22 is provided with the rotor side switch 21 and the rotor net side switch 23, the full power converter 41 may also be provided with a stator side switch and a stator net side switch, the stator side switch is disposed between the side converter 411 of the full power converter 41 and the stator of the generator 10, the stator net side switch is disposed on a side of the net side converter 412 of the full power converter 41 away from the side converter 411, and the stator switch 42 described in the foregoing disclosure may be a stator side switch or a stator net side switch (as shown in fig. 3).

Optionally, the wind generating set further includes a grid-connected switch 80, one end of the grid-connected switch 80 is connected to the grid-side end of the rotor loop 20 and the grid-side end of the stator loop 40 at the same time, and the other end of the grid-connected switch 80 is connected to the grid-connected point a. By arranging the grid-connected switch 80 at the front end of the grid-connected point A, a main switch connected with the grid-connected point A can be provided for the unit, the comprehensive control of the unit is fully ensured, and the use safety is ensured.

Fig. 9 is a flowchart illustrating a control method of a wind turbine generator set according to an embodiment of the present disclosure. It should be appreciated that the controlled wind power plant is a wind power plant of any of the embodiments described above. The control method of the wind generating set according to the embodiment of the disclosure can be executed by a single controller of the wind generating set or by a farm-level controller of a wind farm, and the actual operation condition of each wind generating set needs to be controlled independently when the control method is executed by the farm-level controller.

Referring to fig. 9, in step S901, the output power of a wind turbine generator is acquired. It should be noted that, the control method of the wind generating set according to the embodiment of the disclosure may be continuously executed, for example, real-time output power may be periodically obtained according to a certain frequency, and then subsequent steps are executed based on the obtained output power, so as to implement dynamic continuous control of the wind generating set.

In step S902, in response to determining that the output power is less than or equal to the preset power, the shorting switch and the stator switch are controlled to be closed, and the bypass switch is controlled to be opened. In practice, the rotor side switch 21 and the rotor net side switch 23 on the rotor circuit 20 are also controlled to be opened, so that the rotor circuit 20 is withdrawn from the grid connection, and the grid connection switch 80 is controlled to be closed. The generator 10 now operates as a normal asynchronous generator (i.e. stator side single-ended feed) and the full power converter 41 on the stator loop 40 participates in the grid connection, the full power converter 41 delivering the electrical energy generated by the stator to the grid connection point a. Since the converter involved in the grid connection is the full power converter 41, the current operation mode of the unit may be referred to as a full power mode.

In step S903, in response to determining that the output power is greater than the preset power, the shorting switch and the stator switch are controlled to be opened, and the bypass switch is controlled to be closed. In practice, the rotor side switch 21 and the rotor net side switch 23 on the rotor circuit 20 are controlled to be closed, so that the rotor circuit 20 participates in the grid connection, and the grid connection switch 80 is kept in a closed state. At this time, the generator 10 operates as a doubly-fed asynchronous generator (i.e., the stator side and rotor side double-ended feeds), and the full-power converter 41 on the stator loop 40 is taken out of operation, the electric energy generated by the stator is directly delivered to the grid-connection point a, the rotor converter 22 (using a conventional doubly-fed converter) on the rotor loop 20 participates in grid-connection, and the electric energy generated by the rotor is delivered to the grid-connection point a through the rotor converter 22 and the step-up transformer 70. Since the converters involved in the grid connection are doubly fed converters (i.e. rotor converters 22), the current mode of operation of the unit is a conventional doubly fed mode. It should be understood that, at this time, the electric energy generated by the stator is directly delivered to the grid-connected point a without passing through the step-up transformer 70, and in practice, the rotor-side converter 221 may be used to adjust the rotor voltage, and further adjust the stator output voltage to a medium voltage (for example, 35kV or 10kV as described above), so that the stator loop 40 does not need to be connected to the step-up transformer 70, and for the rotor side, since the rotor-side converter 221 only affects the side voltage of the rotor, the grid-side voltage of the rotor is still low (for example, 690V or 1140V as described above) and the operation of the step-up transformer 70 is not affected.

According to the control method of the wind generating set, the control method of the wind generating set is capable of providing accurate basis for switching of different operation modes and guaranteeing control reliability by configuring preset power and controlling the set to switch between a full power mode and a double-fed mode according to the magnitude relation between output power and the preset power. In addition, the present disclosure addresses the problem of insufficient power generation efficiency of a doubly-fed machine set at light loads (i.e., at low wind speeds), starting from a full power mode at low wind speeds and a conventional doubly-fed mode at high wind speeds, but with different machine sets having different degrees of sensitivity to wind speeds, the same wind speed being of low wind speeds for one machine set and possibly of high wind speeds for another machine set. In this regard, the present disclosure can effectively distinguish whether the unit is in a light load state or a heavy load state by taking the power as the basis parameter for distinguishing the high wind speed from the low wind speed, and further improves the accuracy of control. It should be appreciated that when the wind turbine is in the start-up state, no power output is yet provided, the generator 10 will be a normal asynchronous generator, but for the embodiment of the stator loop 40 further comprising the charging circuit 44 described above, the stator switch 42 is controlled to be opened, the charging switch 442 is controlled to be closed, so that the full power converter 41 can be connected for charging, and the charging circuit 44 operates in a different manner from the operation of the stator switch 42 in the full power operation, but the principle is consistent, all for connecting to the full power converter 41. After entering the normal operation state, it is determined whether to operate the full power mode or the doubly fed mode according to the real-time output power, and the sub-switch 42 is controlled to be closed when the full power mode is determined.

Optionally, the preset power is equal to the product of the rated power of the wind generating set and the preset duty ratio, and the value range of the preset duty ratio is 15% to 30%. The rated power of the wind generating set is the maximum continuous output electric power which is designed to be reached by the wind generating set under the working condition, and reflects the generating capacity of the wind generating set. The product of the rated power and the preset duty ratio is used as the preset power, so that unified rules can be provided for units with different capacities to determine the preset power, and the universality of the rules is improved. As an example, the preset duty cycle is 20%.

Next, a control flow of the wind turbine generator set according to one embodiment of the present disclosure will be described in conjunction with the wind turbine generator set shown in fig. 3.

When the wind turbine shown in fig. 3 is in a start-up state, the rotor converter 22 is cut out, and the rotor of the generator 10 is shorted, so that the doubly-fed asynchronous generator is switched to a common asynchronous generator. The electric energy flows in from the power grid through the grid connection point A, and the direct-current voltage is built by charging the sub-module capacitors of the grid-side converter 412 and the machine-side converter 411 of the full-power converter 41, so that the starting is completed. At this time, the bypass switch 43, the rotor net side switch 23, the rotor side switch 21, and the stator switch 42 are opened, the short circuit switch 30 and the grid-connected switch 80 are closed, the charging switch 442 in the charging circuit 44 is closed, the energy dissipation switch 4132 in the energy dissipation circuit 413 is opened, and the switching devices (for example, controllable devices such as IGBTs and IGCTs) in the side converter 411 and the net side converter 412 of the full power converter 41 are blocked.

When the wind turbine shown in fig. 3 is in a normal operation state, the impeller 60 converts wind energy into mechanical energy, which is converted into ac energy by the generator 10 after being changed in speed through the gear box 50. When the output power is lower than 20% of the rated power (i.e. the preset power), the full-power converter 41 is operated in the full-power mode, the machine side converter 411 converts the ac power into the dc power, and then the grid side converter 412 converts the dc power into the ac power to deliver the power generated by the generator 10 to the grid connection point a. At this time, the bypass switch 43, the rotor mesh side switch 23, the rotor mesh side switch 21, the short circuit switch 30, and the grid-connected switch 80 are all kept in the on-state, the charging switch 442 in the charging circuit 44 is opened, the stator switch 42 is closed, the energy dissipation switch 4132 in the energy dissipation circuit 413 is opened, the switching devices in the mesh side converter 412 and the machine side converter 411 are normally turned on and off, and all the generated power is transmitted to the grid-connected point a. When the output power is greater than 20% of the rated power, the full-power converter 41 is cut out, the rotor converter 22 is put into operation, the system operates in a traditional double-fed mode, most of the alternating current power generated by the generator 10 is transmitted to the grid-connected point A through the stator loop 40, and the small part of the alternating current power is transmitted to the grid-connected point A through the step-up transformer 70 after being converted by the rotor-side converter 221 and the rotor-grid-side converter 222 of the rotor converter 22. At this time, the bypass switch 43, the rotor net side switch 23, the rotor machine side switch 21, and the grid-connected switch 80 are closed, the stator switch 42 and the short-circuit switch 30 are opened, the charging switch 442 in the charging circuit 44 is opened, the energy-consuming switch 4132 in the energy-consuming circuit 413 is opened, and the switching devices in the rotor machine side converter 221 and the rotor net side converter 222 are normally turned on and off, so that the generated partial power is transmitted to the grid-connected point a.

Fig. 10 is a block diagram illustrating a control apparatus of a wind turbine according to an embodiment of the present disclosure.

Referring to fig. 10, a control device 1000 of a wind turbine generator system includes an acquisition unit 1001 and a control unit 1002, and the wind turbine generator system is the wind turbine generator system of any of the above embodiments.

The obtaining unit 1001 may obtain the output power of the wind turbine generator set.

The control unit 1002 may control the short-circuit switch and the stator switch to be closed and the bypass switch to be opened in response to determining that the output power is less than or equal to the preset power.

The control unit 1002 may also control the shorting switch and the stator switch to be opened and the bypass switch to be closed in response to determining that the output power is greater than the preset power.

Optionally, the preset power is equal to the product of the rated power of the wind generating set and the preset duty ratio, and the value range of the preset duty ratio is 15% to 30%.

The specific manner in which the individual units perform the operations in relation to the apparatus of the above embodiments has been described in detail in relation to the embodiments of the method and will not be described in detail here.

The control method of the wind power generation set according to the embodiment of the present disclosure may be written as a computer program and stored on a computer-readable storage medium. When the instructions corresponding to the computer program are executed by the processor, the control method of the wind generating set can be realized. Examples of the computer readable storage medium include: read-only memory (ROM), random-access programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), random-access memory (RAM), dynamic random-access memory (DRAM), static random-access memory (SRAM), flash memory, nonvolatile memory, CD-ROM, CD-R, CD + R, CD-RW, CD+RW, DVD-ROM, DVD-R, DVD + R, DVD-RW, DVD+RW, DVD-RAM, BD-ROM, BD-R, BD-R LTH, BD-RE, blu-ray or optical disk storage, hard Disk Drives (HDD), solid State Disks (SSD), card memory (such as multimedia cards, secure Digital (SD) cards or ultra-fast digital (XD) cards), magnetic tape, floppy disks, magneto-optical data storage, hard disks, solid state disks, and any other means configured to store computer programs and any associated data, data files and data structures in a non-transitory manner and to provide the computer programs and any associated data, data files and data structures to a processor or computer to enable the processor or computer to execute the programs. In one example, the computer program and any associated data, data files, and data structures are distributed across networked computer systems such that the computer program and any associated data, data files, and data structures are stored, accessed, and executed in a distributed manner by one or more processors or computers.

Referring to fig. 11, a computer device 1100 comprises at least one memory 1101 and at least one processor 1102, the at least one memory 1101 having stored therein a set of computer executable instructions that, when executed by the at least one processor 1102, perform a method of controlling a wind turbine generator according to an exemplary embodiment of the present disclosure.

By way of example, the computer device 1100 may be a PC computer, tablet device, personal digital assistant, smart phone, or other device capable of executing the above-described set of instructions. Here, the computer device 1100 need not be a single electronic device, but may be any means or collection of circuits capable of executing the above-described instructions (or instruction set) alone or in combination. The computer device 1100 may also be part of an integrated control system or system manager, or may be configured as a portable electronic device that interfaces with either locally or remotely (e.g., via wireless transmission).

In the computer apparatus 1100, the processor 1102 may include a Central Processing Unit (CPU), a Graphics Processor (GPU), a programmable logic device, a special purpose processor system, a microcontroller, or a microprocessor. By way of example, and not limitation, processors may also include analog processors, digital processors, microprocessors, multi-core processors, processor arrays, network processors, and the like.

The processor 1102 may execute instructions or code stored in the memory 1101, wherein the memory 1101 may also store data. The instructions and data may also be transmitted and received over a network via a network interface device, which may employ any known transmission protocol.

The memory 1101 may be integrated with the processor 1102, for example, RAM or flash memory disposed within an integrated circuit microprocessor or the like. In addition, the memory 1101 may include a stand-alone device, such as an external disk drive, a storage array, or other storage device usable by any database system. The memory 1101 and the processor 1102 may be operatively coupled or may communicate with each other, for example, through an I/O port, a network connection, etc., such that the processor 1102 is able to read files stored in the memory.

In addition, the computer device 1100 may also include a video display (such as a liquid crystal display) and a user interaction interface (such as a keyboard, mouse, touch input device, etc.). All components of computer device 1100 may be connected to each other via buses and/or networks.

The present disclosure provides a wind generating set, a control method, a device and a computer readable storage medium thereof, by setting a short-circuit switch 30, a bypass switch 43 and a full-power converter 41, the short-circuit switch 30 and the stator switch 42 can be closed, the bypass switch 43 is opened (in practice, the switch on the rotor loop 20 can be opened) to enable the rotor loop 20 to exit grid connection, the stator loop 40 with the full-power converter 41 is singly connected to a power grid through a grid connection point a, the generator 10 can be converted into a common asynchronous generator operation (namely, only stator side single-end feed) without being operated, and the full-power converter 41 is utilized to realize the current conversion of a stator side circuit (the rotor current can be regulated by the rotor converter 22 on the rotor loop 20 when the rotor loop 20 is connected, and further the current conversion of the stator side circuit is realized). At this time, the rotor loop 20 exits, and the full-power converter 41 is not affected by slip, so that the rotation speed of the impeller 60 can be reduced to realize an optimal tip speed ratio, thereby improving wind power capture and improving the power generation efficiency of the doubly-fed machine set in light load. The scheme can reduce the cut-in rotating speed of the wind generating set and improve the speed change range of the double-fed generator set, thereby comprehensively improving the generated energy.

While certain embodiments have been shown and described, it would be appreciated by those skilled in the art that changes and modifications may be made to these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.

Claims

1. A wind power generation set, the wind power generation set comprising:

a generator (10);

a rotor circuit (20) connected between the rotor of the generator (10) and a grid connection point;

a short-circuit switch (30) connected between the rotor of the generator (10) and a short-circuit point;

-a stator loop (40) connected between a stator of the generator (10) and the grid connection point, the stator loop (40) comprising a full power converter (41), a stator switch (42) and a bypass switch (43), wherein the full power converter (41) and the stator switch (42) are connected in series and then connected in parallel with the bypass switch (43).

2. A wind turbine as claimed in claim 1, wherein,

The stator output voltage of the generator (10) is matched with the voltage of the power grid into which the wind generating set is integrated;

the wind power plant further comprises a step-up transformer (70) arranged in the rotor circuit (20).

3. A wind turbine as claimed in claim 2, wherein,

the capacity of the step-up transformer (70) is within the range of 20% to 35% of the capacity of the wind power generator set.

4. A wind turbine as claimed in claim 1, wherein,

the full power converter (41) comprises at least one of: modularized multi-level converter and modularized multi-level matrix converter.

5. A wind turbine as claimed in claim 4, wherein,

the submodule of the full-power converter (41) comprises at least one of the following: half-bridge submodule, full-bridge submodule, clamp double submodule, five-switch submodule and half-bridge submodule combined by four capacitors.

6. A wind turbine as claimed in claim 1, wherein,

the rotor loop (20) comprises a rotor side switch (21), a rotor converter (22) and a rotor net side switch (23) which are sequentially connected in series, one end of the rotor side switch (21) is connected between a rotor of the generator (10) and the short-circuit switch (30), and the other end of the rotor side switch (21) is connected with the rotor converter (22).

7. A wind turbine as claimed in claim 1, wherein,

the wind generating set further comprises a grid-connected switch (80), one end of the grid-connected switch (80) is simultaneously connected to the grid-side end of the rotor loop (20) and the grid-side end of the stator loop (40), and the other end of the grid-connected switch (80) is connected to the grid-connected point.

8. A control method of a wind power generation set, characterized in that the wind power generation set is a wind power generation set according to any one of claims 1 to 7, the control method comprising:

obtaining the output power of the wind generating set;

in response to determining that the output power is less than or equal to a preset power, controlling the short-circuit switch and the stator switch to be closed and controlling the bypass switch to be opened;

and in response to determining that the output power is greater than the preset power, controlling the short-circuit switch and the stator switch to be opened and controlling the bypass switch to be closed.

9. The control method according to claim 8, wherein,

the preset power is equal to the product of the rated power of the wind generating set and the preset duty ratio, and the value range of the preset duty ratio is 15-30%.

10. A control device of a wind power plant, characterized in that the wind power plant is a wind power plant according to any one of claims 1 to 7, the control device comprising:

an acquisition unit configured to acquire output power of the wind generating set;

a control unit configured to control the short-circuit switch and the stator switch to be closed and the bypass switch to be opened in response to determining that the output power is less than or equal to a preset power;

the control unit is further configured to control the short-circuit switch and the stator switch to open and the bypass switch to close in response to determining that the output power is greater than the preset power.

11. A computer readable storage medium, characterized in that instructions in the computer readable storage medium, when executed by at least one processor, cause the at least one processor to perform the control method of a wind park according to claim 8 or 9.

12. A computer device, comprising:

at least one processor;

at least one memory storing computer-executable instructions,

wherein the computer executable instructions, when executed by the at least one processor, cause the at least one processor to perform the control method of a wind turbine generator set according to claim 8 or 9.