WO2024066712A1

WO2024066712A1 - Control method and apparatus, and medium, controller and wind generating set

Info

Publication number: WO2024066712A1
Application number: PCT/CN2023/109861
Authority: WO
Inventors: 于笑; 高保峰; 郭锐
Original assignee: 北京金风科创风电设备有限公司
Priority date: 2022-09-29
Filing date: 2023-07-28
Publication date: 2024-04-04
Also published as: CN115313432A; CN115313432B

Abstract

Provided in the present disclosure are a control method and apparatus, and a medium, a controller and a wind generating set. A control method for a voltage-source-type wind generating set comprises: obtaining a phase of a grid-connected-point power-grid voltage of a wind generating set and a grid-connected-point current of same; determining a phase of a virtual internal potential of the wind generating set according to the phase of the grid-connected-point power-grid voltage; obtaining an amplitude of the virtual internal potential of the wind generating set; generating a first modulation signal on the basis of the amplitude and phase of the virtual internal potential; in response to the grid-connected-point current being greater than a first preset threshold value, superposing, to the first modulation signal, a voltage deviation corresponding to a virtual impedance, so as to obtain a second modulation signal; generating a first drive signal on the basis of the second modulation signal; and during short circuiting of a power grid, using the first drive signal to control a grid-side converter of the wind generating set to run.

Description

Control method, device, medium, controller and wind turbine generator set

This application claims priority to the Chinese patent application with application number 202211194971.5 filed on September 29, 2022 and invention name “Control method, device, medium, controller and wind turbine generator set”.

Technical Field

The present disclosure generally relates to the technical field of wind power generation, and more specifically, to a control method, device, medium, controller and wind power generator set of a voltage source type wind power generator set.

Background technique

Generally, a wind power converter adopts a grid-following type or current source control strategy. For example, patent document with publication number CN110572057A discloses a specific harmonic suppression method of a current source converter at an extremely low switching frequency.

However, as the penetration rate of renewable energy generation in the power system gradually increases, the power system shows characteristics such as weakened grid strength and reduced inertia level, increasing the risk of system safety and stability, which restricts the construction and development of new power systems. In order to enhance the supporting role of wind power generation technology to the power system, the development and application of grid-type (voltage source) wind turbines have received extensive attention.

Grid-connected wind turbines still rely on power electronic devices for energy conversion and grid-connected control. Due to the poor overcurrent capability of current power electronic devices, a current limiting control strategy needs to be applied under grid short-circuit faults to prevent the overcurrent protection of the unit from being triggered and causing shutdown and disconnection from the grid.

The current limiting strategy of the grid-connected control technology is a virtual impedance control algorithm, that is, after a short-circuit fault is detected, an equivalent virtual impedance is connected in series between the potential in the grid and the grid connection point to ensure that the grid-connected short-circuit current is within the allowable range of the equipment's safe operating capacity.

Although the virtual impedance control strategy can ensure the safe and reliable operation of networking equipment during short-circuit faults, the low short-circuit current capacity of the equipment itself limits the support ability of the networking equipment to the power grid. In particular, during short-circuit faults, it is unable to provide a large amount of short-circuit reactive current support to the power grid. The voltage fluctuation range of the system nodes is large, which is not conducive to the voltage stability and post-fault recovery of the power system.

The above information may include technical content that is not prior art.

Summary of the invention

The embodiments of the present disclosure provide a control method and a control device for a voltage source type wind turbine generator set, which can enhance the support capability of the voltage source type wind turbine generator set for grid voltage stability.

According to one aspect of the present disclosure, a control method for a voltage source wind turbine generator set includes: obtaining the phase of the grid voltage and the grid current of the wind turbine generator set at the grid connection point; determining the phase of the virtual internal potential of the wind turbine generator set according to the phase of the grid voltage at the grid connection point; obtaining the amplitude of the virtual internal potential of the wind turbine generator set; generating a first modulation signal based on the amplitude and phase of the virtual internal potential; in response to the grid current being greater than a first preset threshold, superimposing a voltage deviation corresponding to the virtual impedance on the first modulation signal to obtain a second modulation signal; generating a first drive signal based on the second modulation signal; and during a grid short circuit, controlling the operation of a grid-side converter of the wind turbine generator set using the first drive signal.

According to a second aspect of the present disclosure, a control device of a voltage source wind turbine generator set includes: a grid voltage phase detection unit, which obtains the phase of the grid voltage at the grid connection point of the wind turbine generator set; a synchronization unit, which determines the phase of the virtual internal potential of the wind turbine generator set according to the phase of the grid voltage at the grid connection point; an internal potential amplitude determination unit, which obtains the amplitude of the virtual internal potential of the wind turbine generator set; a modulation unit, which generates a first modulation signal based on the amplitude and phase of the virtual internal potential and superimposes a voltage deviation corresponding to the virtual impedance on the first modulation signal in response to a grid connection point current being greater than a first preset threshold to obtain a second modulation signal and generates a first drive signal based on the second modulation signal; a grid-side converter control unit, which uses the first drive signal to control the operation of the grid-side converter of the wind turbine generator set during a grid short circuit.

According to a third aspect of the present disclosure, a computer-readable storage medium storing a computer program is provided, which implements the above control method when the computer program is executed by a processor.

According to a fourth aspect of the present disclosure, a controller is provided, the controller comprising: a processor; a memory storing a computer program, and when the computer program is executed by the processor, the control method of the voltage source wind turbine generator set described above is implemented.

According to a fifth aspect of the present disclosure, a wind turbine generator set is provided, the wind turbine generator set comprising the control device of the voltage source type wind turbine generator set.

According to the control method and control device of the voltage source wind turbine generator set of the embodiment of the present disclosure, it is possible to increase the short-circuit current level to above 1.5pu (rated current) during a short-circuit fault while maintaining the thermal balance of the power semiconductor and the safety constraints of shutting down overvoltage.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG1 is a block diagram showing a control system of a voltage source type wind turbine generator set;

2 is a flow chart showing a control method of a voltage source type wind turbine generator set according to an embodiment of the present disclosure;

3 is a flow chart showing a control method of a voltage source type wind turbine generator set according to an embodiment of the present disclosure;

4 is a flow chart showing a control method of a voltage source wind turbine generator set according to an embodiment of the present disclosure;

5 is a flow chart showing a control method of a voltage source wind turbine generator set according to an embodiment of the present disclosure;

6 is a flow chart showing a control method of a voltage source wind turbine generator set according to an embodiment of the present disclosure;

7 is a flow chart showing a control method of a voltage source wind turbine generator set according to an embodiment of the present disclosure;

8 is a block diagram showing a control device of a voltage source type wind turbine generator set according to an embodiment of the present disclosure;

FIG. 9 is a block diagram showing a control device of a voltage source type wind turbine generator system according to an embodiment of the present disclosure.

Detailed ways

The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and/or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and/or systems described herein will be clear. For example, the order of operations described herein is only an example and is not limited to those orders set forth herein, but can be changed as will be clear after understanding the disclosure of the present application, except for operations that must occur in a specific order. In addition, for greater clarity and simplicity, the description of features known in the art may be omitted.

The features described herein may be implemented in different forms and should not be construed as being 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, many of which are contemplated in the present application. Please make it clear after disclosure.

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

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

The terms used herein are only used to describe various examples and are not intended to limit the disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "comprise", "include" and "have" indicate the presence of the described features, quantities, operations, components, elements and/or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements and/or combinations thereof.

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

Furthermore, in the description of examples, when it is considered that a detailed description of a well-known related structure or function will cause vague interpretation of the present disclosure, such a detailed description will be omitted.

The control method of the voltage source wind turbine generator set according to the embodiment of the present disclosure can be applied to the case where a short circuit occurs in the power system. By virtual impedance control, switching frequency reduction control, lowering the opening threshold of the brake unit, maintaining the DC bus voltage, etc., the short-circuit current level of the voltage source wind turbine generator set can be significantly increased to more than 1.5 pu. The specific implementation method according to the embodiment of the present disclosure is described in detail below with reference to Figures 1 to 9.

FIG. 1 is a block diagram showing a control system of a voltage source type wind turbine generator system.

The control system of the voltage source wind turbine generator set according to the embodiment of the present disclosure may include a main controller 160 , a pitch controller 170 , a machine-side converter controller 180 , and a grid-side converter controller 150 .

The generator-side converter controller 180 is mainly used to control the DC bus voltage to be constant, measure and calculate the power generation The electromagnetic torque of the machine 110 is fed back to the main controller 160 to control the switch tube of the machine-side converter 120. The main controller 160 sends a pitch angle instruction to the pitch controller 170 to adjust the mechanical torque input to the impeller, and sends a torque or power instruction to the grid-side converter controller 150 to indirectly control the electromagnetic torque of the generator. The grid-side converter controller 150 can be used to control the grid-side converter 130 and can execute the core algorithm of grid-type control and virtual impedance control technology.

Although not shown, the control system of the voltage source wind turbine generator set according to the embodiment of the present disclosure may also include a controller for controlling a braking unit, where the braking unit refers to a braking module that discharges a high voltage on the DC bus when, for example, high voltage ride-through occurs. The internal potential or virtual internal potential according to the embodiment of the present disclosure refers to the potential at a node (e.g., node E) between the output end of the grid-side converter 130 and the LC filter 140. In addition, the control method described below may be executed by a main controller, a grid-side converter controller, and/or a machine-side converter controller, etc.

2 to 7 are flow charts illustrating a control method of a voltage source wind turbine generator system according to an embodiment of the present disclosure.

As shown in FIG. 2 , the control method of the voltage source wind turbine generator set according to the embodiment of the present disclosure may include step S110 , step S120 , step S130 , step S140 , step S150 , step S160 , and step S170 .

In step S110, the phase of the grid voltage V1 and the grid current I1 of the wind turbine generator set can be obtained. The grid voltage V1 is the grid voltage at the grid point of the entire wind turbine generator set.

As an example, the grid voltage and grid current at the grid connection point can be obtained through corresponding sensors, and the phase of the grid voltage at the grid connection point can be obtained by performing phase locking using a phase-locked loop (PLL). Different from the prior art, the control method according to the embodiment of the present disclosure can execute PLL once before executing the grid-connected control algorithm to obtain the phase of the grid voltage at the grid connection point, without the need to always execute PLL during the execution of the algorithm.

In step S120, the phase of the virtual internal potential of the wind turbine generator set may be determined according to the phase of the grid voltage at the grid connection point.

As an example, the step of determining the phase of the virtual internal potential of the wind turbine generator set based on the phase of the grid voltage at the grid connection point may include: determining the phase of the virtual internal potential of the wind turbine generator set based on the phase of the grid voltage at the grid connection point, the torque/power command value received from the main controller, and the active power measurement value of the wind turbine generator set.

Optionally, according to the phase of the grid voltage at the grid connection point, the torque/power command received from the main controller The step of determining the phase of the virtual internal potential of the wind turbine generator set may include: performing PI regulation on the difference between the torque/power command value received from the main controller and the active power measurement value of the wind turbine generator set to obtain the angular frequency, calculating the integral value of the angular frequency with the phase of the grid voltage at the grid connection point as the initial value, thereby determining the phase of the virtual internal potential of the wind turbine generator set.

For example, the difference between the torque power command value and the measured active power value (i.e., the output active power measured at the grid connection point or the outlet of the entire wind turbine generator set) can be subjected to PI regulation to obtain the angular frequency, and then the angular frequency is calculated with the phase of the grid voltage at the grid connection point as the integral value of the initial value, thereby determining the phase of the virtual internal potential of the wind turbine generator set. The torque power command value can be converted into a power command value (power is the product of torque and speed), and then the difference between the converted power command value and the measured active power value is subjected to PI regulation to obtain the angular frequency, and then the angular frequency is calculated with the phase of the grid voltage at the grid connection point as the integral value of the initial value, thereby determining the phase of the virtual internal potential of the wind turbine generator set.

The phase of the virtual internal potential can also be obtained through the inertia link. For example, the phase of the grid voltage at the grid connection point can be obtained through first-order and/or second-order low-pass filtering, or the phase of the grid voltage at the grid connection point can be obtained through a combination of the inertia link and a PI controller (or PI algorithm).

Optionally, when the phase of the internal potential is obtained based on PI regulation, the appropriate response speed can be obtained by adjusting the proportional coefficient and integral coefficient of the PI link. When the phase of the internal potential is obtained by low-pass filtering, the appropriate response speed can be obtained by adjusting the filter parameters (e.g., cutoff frequency).

In step S130, the magnitude of the virtual internal potential of the wind turbine generator system is obtained.

As an example, a PI adjustment may be performed on the difference between the reactive power/voltage command value received from the main controller and the voltage feedback value of the converter of the wind turbine generator system to obtain the magnitude of the virtual internal potential.

Specifically, the difference between the reactive power/voltage command value received from the main controller and the voltage feedback value of the converter of the wind turbine generator set may be PI regulated to obtain the amplitude of the virtual internal potential.

In step S140, a first modulation signal is generated based on the amplitude and phase of the virtual internal potential.

The first modulation signal may be a sine wave signal, and the first modulation signal may be directly obtained according to the amplitude and phase of the obtained virtual internal potential.

In step S1501 , the magnitude relationship between the grid-connected point current I1 and the first preset threshold Th1 may be determined.

In step S150 , in response to the grid-connected point current I1 being greater than the first preset threshold Th1 , a voltage deviation corresponding to the virtual impedance is superimposed on the first modulation signal to obtain a second modulation signal.

The virtual impedance here can be predetermined. For example, the feedback grid-connected current can be compared with the predetermined The virtual impedance of the first modulation signal is multiplied by the virtual impedance to obtain a voltage deviation, and the voltage deviation is superimposed on the first modulation signal to obtain a second modulation signal. The virtual impedance control scheme here can reduce the output current of the grid-side converter.

In step S160, a first driving signal is generated based on the second modulation signal. For example, the second modulation signal may be loaded into a pulse width modulation (PWM) unit, and the pulse width modulation unit generates the first driving signal based on the second modulation signal.

In step S170, during a grid short circuit, the grid-side converter of the wind turbine generator set is controlled to operate using a first drive signal.

Whether the power grid is short-circuited can be determined by the magnitude relationship between the grid connection point current I1 and the first preset threshold Th1.

According to an embodiment of the present disclosure, meshing control may be performed based on the magnitude and phase of the internal potential and virtual impedance control.

3 , the control method according to an embodiment of the present disclosure further includes: in response to the grid connection point current being greater than a first preset threshold and the grid voltage at the grid connection point being lower than a second preset threshold, maintaining the phase and amplitude of the virtual internal potential at the phase and amplitude before the grid short circuit during a grid short circuit.

During the control process of the grid-connected wind turbine generator set, the amplitude and phase of the internal potential can be locked to keep both at the steady-state value before the fault, enabling virtual impedance control and limiting the amplitude of the grid-connected short-circuit current within a certain range, which can be at least greater than 1.5pu (rated current).

In step S1502, the magnitude relationship between the grid voltage V1 at the grid connection point and the second preset threshold Th2 can be determined. Step S1501 and step S1502 can both be part of the control method disclosed in the present invention.

4 , the control method according to the embodiment of the present disclosure may further include step S180 .

In step S180, in response to the current at the grid connection point I1 being greater than the first preset threshold value Th1 and the grid voltage V1 at the grid connection point being lower than the second preset threshold value Th2, during a grid short circuit, the machine-side converter of the wind turbine generator set is controlled to operate so as to keep the DC bus voltage of the wind turbine generator set stable.

Specifically, referring to FIG. 7 , step S180 of controlling the DC bus voltage to remain stable may include step S1801 , step S1802 , step S1803 , step S1804 and step S1805 .

In step S1801, a vector phase of a terminal voltage of a generator of a wind turbine generator set may be obtained.

As an example, the generator side voltage may be determined by detecting the three-phase current on the generator side and the resistance impedance on the generator side, and then the vector phase of the machine terminal voltage may be determined based on the generator side voltage.

In step S1802, a q-axis current value may be obtained based on the DC bus voltage.

As an example, obtaining the q-axis current value based on the DC bus voltage may include: obtaining the q-axis current value by performing PI regulation on the DC bus voltage, and a reference value or a given value of the DC bus voltage may be preset.

In step S1803, the d-axis current value may be obtained based on the machine terminal voltage.

As an example, the step of obtaining the d-axis current value based on the machine-end voltage may include: performing PI regulation on a difference between the machine-end voltage and a reference value of the machine-end voltage to obtain the d-axis current value.

In step S1804 , a modulation signal is determined according to the vector phase, the q-axis current value, and the d-axis current value, and a second drive signal is generated based on the modulation signal.

As an example, the step of determining the modulation signal according to the vector phase, the q-axis current value, and the d-axis current value may include: performing PI regulation using the vector phase, the q-axis current value, and the d-axis current value to obtain the modulation signal.

Specifically, PI regulation can be performed on the difference between the q-axis current value and the q-axis current reference value to obtain the angular frequency, and then an integration with the vector phase as the initial value can be performed to obtain the phase. PI regulation can be performed on the difference between the d-axis current value and the d-axis current reference value to obtain the amplitude, and the modulation signal can be directly obtained according to the obtained amplitude and phase. As an example, PI regulation can also be performed on the difference between the d-axis current value and the d-axis current reference value to obtain the amplitude, and PI regulation can be performed on the difference between the q-axis current value and the q-axis current reference value to obtain the phase.

In step S1805, the second driving signal is used to control the operation of the machine-side converter of the wind turbine generator set so as to keep the DC bus voltage of the wind turbine generator set stable.

The DC bus voltage stabilization control method described above is only an example, and the DC bus voltage stabilization can also be controlled in other ways.

When the DC bus voltage rises abnormally, the brake unit can be controlled to start action to dissipate the overflow power on the DC side.

5 , the control method according to the embodiment of the present disclosure may further include step S190 .

In step S190, in response to the current at the grid connection point I1 being greater than the first preset threshold Th1 and the grid voltage V1 at the grid connection point being lower than the second preset threshold Th2, during a grid short circuit, the start-up voltage of the brake unit of the converter of the wind turbine generator set is reduced.

6 , the control method according to the embodiment of the present disclosure may further include step S200 .

In step S200, in response to the grid connection point I1 current being greater than the first preset threshold Th1 and the grid connection point current being When the grid voltage V1 is lower than the second preset threshold value Th2, the frequency of the first driving signal is reduced. For example, the frequency of the carrier signal may be changed to change the frequency of the first driving signal.

Similarly, the magnitude relationship between the grid voltage V1 at the grid connection point and the second preset threshold Th2 may be determined in step S1502. Step S1501 and step S1502 may both be part of the control method disclosed herein.

It should be noted that at least two of the step of maintaining the phase and amplitude before the grid short circuit, step S180, step S190 and step S200 may be executed in parallel or sequentially, and the execution order is not specifically limited.

Descriptions of the steps in FIGS. 3 to 6 that are the same as those in FIG. 2 are omitted here.

8 and 9 are block diagrams illustrating a control device of a voltage source type wind turbine generator system according to an embodiment of the present disclosure.

As shown in FIG. 8 , the control device 500 of the voltage source wind turbine generator set according to an embodiment of the present disclosure may include a grid voltage phase detection unit 510 , a synchronization unit 520 , an internal potential amplitude determination unit 530 , a modulation unit 540 and a grid-side converter control unit 550 .

The grid voltage phase detection unit 510 can obtain the phase of the grid voltage at the grid connection point of the wind turbine generator set. The grid voltage phase detection unit can be used to detect the phase of the grid voltage before the converter is started.

The synchronization unit 520 may determine the phase of the virtual internal potential of the wind turbine generator set according to the phase of the grid voltage at the grid connection point.

The synchronization unit 520 can be implemented by an inertia link. For example, the synchronization unit 520 can obtain the phase of the virtual internal potential of the wind turbine generator set by first-order and/or second-order low-pass filtering, or can obtain the phase of the virtual internal potential of the wind turbine generator set by a combination of an inertia link and PI. The synchronization unit 520 can determine the phase of the virtual internal potential of the wind turbine generator set according to the phase of the grid voltage at the grid connection point, the torque/power command value received from the main controller, and the active power measurement value of the wind turbine generator set.

The internal potential amplitude determination unit 530 may obtain the amplitude of the virtual internal potential of the wind turbine generator set.

The internal potential amplitude determination unit 530 may perform PI regulation on the difference between the reactive power/voltage command value received from the main controller and the voltage feedback value of the converter of the wind turbine generator set to obtain the amplitude of the virtual internal potential.

The internal potential amplitude determination unit 530 may perform PI regulation on the difference between the torque power command value and the active power measurement value (i.e., the output active power measured at the grid connection point or the outlet of the entire wind turbine generator set) to obtain the angular frequency, and then calculate the integral value of the angular frequency with the phase of the grid voltage at the grid connection point as the initial value, thereby determining the phase of the virtual internal potential of the wind turbine generator set. The internal potential amplitude determination unit 530 may also convert the torque power command value into a power command value (power is the product of torque and speed), and then The difference between the converted power command value and the active power measurement value is subjected to PI regulation to obtain the angular frequency, and then the angular frequency is calculated with the phase of the grid voltage at the grid connection point as the integral value of the initial value to determine the phase of the virtual internal potential of the wind turbine generator set.

The modulation unit 540 can generate a first modulation signal based on the amplitude and phase of the virtual internal potential and superimpose a voltage deviation corresponding to the virtual impedance on the first modulation signal in response to the grid-connected point current being greater than a first preset threshold to obtain a second modulation signal and generate a first drive signal based on the second modulation signal.

The grid-side converter control unit 550 may use the first drive signal to control the operation of the grid-side converter of the wind turbine generator set during a grid short circuit.

As an example, whether the grid voltage at the grid connection point is short-circuited may be determined by the grid-side converter control unit 550, which may be a part of the grid-side converter controller, a part of the machine-side converter controller, or a part of the main controller. For example, when the grid connection point current exceeds a predetermined threshold, it may be determined that a grid short circuit occurs.

According to the embodiment of the present disclosure, the control device 500 of the voltage source wind turbine generator set may further include a machine-side converter controller, which may control the operation of the machine-side converter of the wind turbine generator set in response to the grid-connected point current being greater than a first preset threshold and the grid voltage at the grid-connected point being lower than a second preset threshold during a grid short circuit to keep the DC bus voltage of the wind turbine generator set stable.

The machine-side converter controller can be configured to: obtain the vector phase of the machine-side voltage of the generator of the wind turbine generator set; obtain the q-axis current value based on the DC bus voltage; obtain the d-axis current value based on the machine-side voltage; determine the modulation signal according to the vector phase, the q-axis current value, and the d-axis current value and generate a second drive signal based on the modulation signal; use the second drive signal to control the operation of the machine-side converter of the wind turbine generator set under the grid voltage disturbance at the grid connection point, so as to keep the DC bus voltage of the wind turbine generator set stable.

As an example, the machine-side converter controller may be further configured to perform PI regulation using the vector phase, the q-axis current value, and the d-axis current value to obtain a modulation signal. The machine-side converter controller may obtain the q-axis current value by performing PI regulation on the DC bus voltage, and the machine-side converter controller may be further configured to perform PI regulation on the machine-end voltage and the difference between the reference value of the machine-end voltage to obtain the d-axis current value.

Specifically, the machine-side converter controller can perform PI regulation on the difference between the q-axis current value and the q-axis current reference value to obtain the angular frequency, and then calculate the integral value of the angular frequency with the vector phase as the initial value to obtain the phase. The machine-side converter controller can perform PI regulation on the difference between the d-axis current value and the d-axis current reference value to obtain the amplitude, and the modulation signal can be directly obtained according to the obtained amplitude and phase. As an example, the machine-side converter controller can also perform PI regulation on the difference between the d-axis current value and the d-axis current reference value to obtain the amplitude, The phase is obtained by performing PI adjustment on the difference between the q-axis current value and the q-axis current reference value.

The modulation unit 540 may be configured to maintain the phase and amplitude of the virtual internal potential at the phase and amplitude before the grid short circuit during a grid short circuit in response to the grid current being greater than a first preset threshold and the grid voltage being lower than a second preset threshold.

According to an embodiment of the present disclosure, the control device may further include a braking control unit, which may be configured to reduce the start-up voltage of the braking unit of the converter of the wind turbine generator set in response to the grid current being greater than a first preset threshold and the grid voltage being lower than a second preset threshold.

The modulation unit 540 may be configured to reduce the frequency of the first drive signal in response to the grid-connected point current being greater than a first preset threshold and the grid voltage at the grid-connected point being lower than a second preset threshold. As described above, the modulation unit may change the frequency of the first drive signal using a carrier signal. For example, the switching frequency of the modulation link (i.e., the switching frequency of the PWM drive signal) may be reduced to below 1.7 kHz to reduce the excessive increase in junction temperature caused by power semiconductor switching losses and maintain thermal balance of the power module.

The control method according to the embodiment of the present disclosure can be written as a computer program and stored in a computer-readable storage medium. When the computer program is executed by a processor, the control method of the voltage source wind turbine generator set as described above can be implemented.

Examples of computer-readable storage media 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 drive (HDD), solid state drive (SSD), card storage (such as, MultiMediaCard, Secure Digital (SD) card or Extreme Digital (XD) card), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid state disk and any other device, the any other device is configured to store the computer program and any associated data, data files and data structures in a non-transitory manner and provide the computer program and any associated data, data files and data structures to a processor or computer so that the processor or computer can execute the computer program.

In one example, a computer program and any associated data, data files, and data structures are distributed across networked computer systems so that the computer program and any associated data, data files, and data structures are stored, accessed, and executed in a distributed fashion by one or more processors or computers.

As shown in Figure 9, the controller 600 (for example, a machine-side converter controller, a grid-side converter controller and/or a main controller) may include a processor 610 and a memory 620, and the memory stores a computer program. When the computer program is executed by the processor, the control method of the voltage source wind turbine generator set as described above is implemented.

The control device of the voltage source type wind turbine generator set as described above may be a part of a wind turbine generator set (eg, a voltage source type wind turbine generator set).

The control method and control device according to the embodiments of the present disclosure can enhance the supporting capability of the voltage source type wind turbine generator set for grid voltage stability.

Although some embodiments of the present disclosure have been shown and described, those skilled in the art should understand that these embodiments may be modified without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents. For example, technical features in different embodiments may be combined to form new technical solutions.

Claims

A control method for a voltage source wind turbine generator set, characterized in that the control method comprises:

Obtaining the phase of the grid voltage and the grid current of the wind turbine generator set at the grid connection point;

Determining the phase of the virtual internal potential of the wind turbine generator set according to the phase of the grid voltage at the grid connection point;

Obtaining the amplitude of the virtual internal potential of the wind turbine generator set;

generating a first modulation signal based on the amplitude and phase of the virtual internal potential;

In response to the grid-connected point current being greater than a first preset threshold, superimposing a voltage deviation corresponding to the virtual impedance on the first modulation signal to obtain a second modulation signal;

generating a first drive signal based on the second modulation signal;

During a grid short circuit, the first drive signal is used to control the operation of the grid-side converter of the wind generator set.
The control method of the voltage source wind turbine generator set according to claim 1 is characterized in that the control method also includes: in response to the grid connection point current being greater than a first preset threshold and the grid voltage at the grid connection point being lower than a second preset threshold, maintaining the phase and amplitude of the virtual internal potential at the phase and amplitude before the grid short circuit during the grid short circuit.
The control method of a voltage source wind turbine generator set according to claim 1 is characterized in that the control method further comprises: in response to the grid connection point current being greater than a first preset threshold value and the grid voltage at the grid connection point being lower than a second preset threshold value, during a grid short circuit, controlling the operation of the machine-side converter of the wind turbine generator set to keep the DC bus voltage of the wind turbine generator set stable.
The control method of a voltage source wind turbine generator set according to claim 1 is characterized in that the control method further comprises: in response to the grid-connected point current being greater than a first preset threshold and the grid voltage at the grid-connected point being lower than a second preset threshold, reducing the start-up voltage of a braking unit of the converter of the wind turbine generator set.
The control method of a voltage source wind turbine generator set according to any one of claims 1 to 4 is characterized in that the control method further comprises: in response to the grid connection point current being greater than a first preset threshold and the grid voltage at the grid connection point being lower than a second preset threshold, reducing the frequency of the first drive signal.
The control method of a voltage source wind turbine generator set according to claim 1 is characterized in that The step of determining the phase of the virtual internal potential of the wind turbine generator set according to the phase of the grid voltage at the grid connection point includes: determining the phase of the virtual internal potential of the wind turbine generator set according to the phase of the grid voltage at the grid connection point, the torque/power command value received from the main controller and the active power measurement value of the wind turbine generator set.
The control method of a voltage source wind turbine generator set according to claim 6 is characterized in that the step of determining the phase of the virtual internal potential of the wind turbine generator set according to the phase of the grid voltage at the grid connection point, the torque/power command value received from the main controller and the active power measurement value of the wind turbine generator set comprises:

performing PI regulation on the difference between the torque/power command value and the measured active power value of the wind turbine generator set to obtain an angular frequency,

The angular frequency is calculated by taking the phase of the grid voltage at the grid connection point as an integral value of an initial value, thereby determining the phase of the virtual internal potential of the wind turbine generator set.
The control method of a voltage source wind turbine generator set according to claim 1, characterized in that the step of obtaining the amplitude of the virtual internal potential of the wind turbine generator set comprises:

The difference between the reactive power/voltage command value received from the main controller and the voltage feedback value of the converter of the wind turbine generator set is PI regulated to obtain the amplitude of the virtual internal potential.
A control device for a voltage source type wind turbine generator set, characterized in that the control device comprises:

A grid voltage phase detection unit, which obtains the phase of the grid voltage at the grid connection point of the wind turbine generator set;

A synchronization unit, which determines the phase of the virtual internal potential of the wind turbine generator set according to the phase of the grid voltage at the grid connection point;

An internal potential amplitude determination unit, for obtaining the amplitude of a virtual internal potential of the wind turbine generator set;

a modulation unit, generating a first modulation signal based on the amplitude and phase of the virtual internal potential and, in response to the grid-connected point current being greater than a first preset threshold, superimposing a voltage deviation corresponding to the virtual impedance on the first modulation signal to obtain a second modulation signal and generating a first drive signal based on the second modulation signal;

The grid-side converter control unit uses the first drive signal to control the operation of the grid-side converter of the wind turbine generator set during the grid short circuit.
The control device of the voltage source type wind turbine generator set according to claim 9 is characterized in that the control device further comprises: a machine-side current converter controller configured to respond to the grid connection point current being greater than a first preset threshold value and the grid voltage at the grid connection point being lower than a second preset threshold value, in the event of a grid short circuit. During the period of power failure, the machine-side converter of the wind turbine generator set is controlled to operate so that the DC bus voltage of the wind turbine generator set remains stable.
The control device of the voltage source wind turbine generator set according to claim 9 or 10 is characterized in that the modulation unit is configured to: in response to the grid connection point current being greater than a first preset threshold and the grid voltage at the grid connection point being lower than a second preset threshold, maintain the phase and amplitude of the virtual internal potential at the phase and amplitude before the grid short circuit during the grid short circuit.
The control device of the voltage source wind turbine generator set according to claim 9 is characterized in that the control device also includes: a braking control unit configured to reduce the start-up voltage of the braking unit of the converter of the wind turbine generator set in response to the grid current being greater than a first preset threshold and the grid voltage at the grid connection point being lower than a second preset threshold.
The control device of the voltage source wind turbine generator set according to claim 9 is characterized in that the modulation unit is configured to: reduce the frequency of the first drive signal in response to the grid connection point current being greater than a first preset threshold and the grid voltage at the grid connection point being lower than a second preset threshold.
A computer-readable storage medium storing a computer program, characterized in that when the computer program is executed by a processor, the control method according to any one of claims 1 to 8 is implemented.
A controller, characterized in that the controller comprises:

processor;

A memory storing a computer program, which, when executed by a processor, implements the control method of a voltage source wind turbine generator set according to any one of claims 1 to 8.
A wind turbine generator set, characterized by comprising the control device for a voltage source wind turbine generator set according to any one of claims 9 to 13.