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

Abstract

The present disclosure provides a control method, device, controller, and storage medium for a wind turbine generator set. The control method for the wind turbine generator set includes: monitoring whether a grid power failure occurs, disconnecting the grid-connected terminal of the wind turbine generator set from the grid; in response to monitoring the occurrence of a grid power failure, switching a protection mode to a grid power failure protection mode; in response to entering the grid power failure protection mode, controlling the wind turbine generator set to remain in a continuous operating state; and in response to entering the grid power failure protection mode for a first preset duration, controlling the wind turbine generator set to shut down.

Description

Technical Field

[0001] The present disclosure generally relates to the field of wind power generation technology, and more specifically, to a control method, device, controller, and storage medium for a wind turbine generator set. Background Art

[0002] During the operation of a wind turbine (hereinafter referred to as a wind turbine), especially during high-power operation, when a power outage occurs, the energy produced by the wind turbine cannot be fed into the grid. Energy circulation will cause the voltage and frequency at the wind turbine's grid-connected end to increase rapidly. When the wind turbine detects overfrequency or overvoltage, it will usually stop and disconnect from the grid. Summary of the Invention

[0003] An exemplary embodiment of the present disclosure provides a control method, device, controller, and storage medium for a wind turbine generator set, which can effectively protect the wind turbine safety when a power grid power failure occurs.

[0004] According to a first aspect of an embodiment of the present disclosure, a control method for a wind turbine generator set is provided, comprising: monitoring whether a grid power failure occurs in which the grid-connected end of the wind turbine generator set is disconnected from the grid; in response to monitoring the occurrence of a grid power failure, switching a protection mode to a grid power failure protection mode; in response to entering the grid power failure protection mode, controlling the wind turbine generator set to remain in operation; in response to entering the grid power failure protection mode for a first preset duration, controlling the wind turbine generator set to shut down.

[0005] Optionally, it also includes: in response to entering the grid power-off fault protection mode, monitoring whether the DC bus voltage is overvoltage and whether the converter current is overcurrent; in response to the DC bus voltage being higher than a first voltage threshold or the converter current being higher than a first current threshold, controlling the wind turbine generator set to shut down; in response to the DC bus voltage being higher than a second voltage threshold but not higher than the first voltage threshold for a continuous period reaching a second preset period, or the converter current being higher than a second current threshold but not higher than the first current threshold for a continuous period reaching a second preset period, controlling the wind turbine generator set to shut down; wherein, the first preset period is longer than the second preset period.

[0006] Optionally, the step of controlling the wind turbine generator set to be continuously in operation includes: controlling the grid-connected terminal voltage to be continuously at a target voltage value; and controlling the output torque of the generator to be continuously at a target torque value.

[0007] Optionally, the target voltage value is set based on the upper voltage limit that the hardware of the wind turbine generator set can withstand and the voltage control requirement for grid power failure; and / or, the target torque value is set based on the upper current limit that the hardware of the wind turbine generator set can withstand and the load reduction requirement for grid power failure.

[0008] Optionally, the converter of the wind turbine generator set includes: a machine-side converter and a grid-side converter; wherein, the step of controlling the grid-connected terminal voltage to be continuously at the target voltage value includes: controlling the output voltage of the grid-side converter and the reactive current output by the machine-side converter, so that the grid-connected terminal voltage is continuously at the target voltage value; or, controlling the output voltage of the grid-side converter and the reactive current output by the grid-side converter, so that the grid-connected terminal voltage is continuously at the target voltage value; or, controlling the output voltage of the generator stator and the reactive current output by the machine-side converter, so that the grid-connected terminal voltage is continuously at the target voltage value; or, controlling the output voltage of the generator stator and the reactive current output by the grid-side converter, so that the grid-connected terminal voltage is continuously at the target voltage value.

[0009] Optionally, the converter of the wind turbine generator set includes: a machine-side converter and a grid-side converter; wherein, the step of controlling the output torque of the generator to be continuously at the target torque value includes: controlling the active current output by the machine-side converter and starting the braking resistor so that the output torque of the generator is continuously at the target torque value.

[0010] Optionally, the step of controlling the wind turbine generator set to remain in operation also includes: in response to the output torque of the generator being maintained at the target torque value for a duration reaching a third preset duration, controlling the generator to stop outputting the torque; wherein the first preset duration is longer than or equal to the third preset duration, and the third preset duration is set based on the load reduction requirement for a power grid power failure.

[0011] Optionally, the step of controlling the output torque of the generator to continuously be at the target torque value includes: controlling the output torque of the generator to continuously be at the target torque value through a current converter controller.

[0012] Optionally, the step of monitoring whether a grid power failure occurs in which the grid-connected end of the wind turbine generator set is disconnected from the grid includes: determining that a grid power failure occurs in response to power being higher than a power threshold, grid-connected end current being lower than a current threshold, and grid-connected end voltage being higher than a voltage threshold.

[0013] According to a second aspect of an embodiment of the present disclosure, a control device for a wind turbine generator set is provided, including: a fault monitoring unit, configured to monitor whether a grid power failure occurs in which the grid-connected end of the wind turbine generator set is disconnected from the grid; a mode switching unit, configured to switch the protection mode to a grid power failure protection mode in response to detecting the occurrence of a grid power failure; an operation control unit, configured to control the wind turbine generator set to remain in an operating state in response to entering the grid power failure protection mode; and a shutdown control unit, configured to control the wind turbine generator set to shut down in response to entering the grid power failure protection mode for a first preset time period.

[0014] According to a third aspect of an embodiment of the present disclosure, a computer-readable storage medium storing a computer program is provided. When the computer program is executed by a processor, the processor is prompted to execute the control method of the wind turbine generator set as described above.

[0015] According to a fourth aspect of an embodiment of the present disclosure, a controller of a wind turbine generator set is provided, the controller comprising: a processor; and a memory storing a computer program, which, when executed by the processor, prompts the processor to execute the control method of the wind turbine generator set as described above.

[0016] According to a fifth aspect of an embodiment of the present disclosure, there is provided a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the control method of the wind turbine generator set as described above is implemented.

[0017] The control method, device, controller and storage medium of the wind turbine generator set according to the exemplary embodiment of the present disclosure can effectively reduce the risk of wind turbine hardware failure and effectively reduce the extreme load impact of components such as blades and towers when a power outage occurs.

[0018] In the following description, some aspects and / or advantages of the general inventive concept of the present disclosure will be set forth, and some aspects and / or advantages will be known through the following description or implementation of the general inventive concept of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] These and / or other aspects and advantages of the present application will become more clear and easier to understand from the following detailed description of the embodiments of the present application in conjunction with the accompanying drawings, in which:

[0020] Figure 1 The voltage waveform diagram when the grid loses power is shown;

[0021] Figure 2 A flow chart showing a method for controlling a wind turbine generator system according to an exemplary embodiment of the present disclosure;

[0022] Figure 3 A schematic structural diagram of a wind turbine generator set according to an exemplary embodiment of the present disclosure is shown;

[0023] Figure 4 A flowchart illustrating a method for monitoring whether a power grid power failure occurs according to an exemplary embodiment of the present disclosure;

[0024] Figure 5 A flow chart showing a method for controlling a wind turbine generator system according to another exemplary embodiment of the present disclosure;

[0025] Figure 6 A structural block diagram of a control device for a wind turbine generator system according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0026] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like parts throughout. The embodiments are described below with reference to the drawings so as to explain the present disclosure.

[0027] It should be noted that the terms "first," "second," and the like in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the numbers used in this manner are interchangeable where appropriate so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure as detailed in the appended claims.

[0028] It should be noted that the phrase "at least one of the items" in this disclosure includes three types of parallel situations: "any one of the items", "a combination of any multiple items of the items", and "all of the items". For example, "including at least one of A and B" includes the following three parallel situations: (1) including A; (2) including B; (3) including A and B. For another example, "performing at least one of step 1 and step 2" includes the following three parallel situations: (1) performing step 1; (2) performing step 2; and (3) performing steps 1 and 2.

[0029] On the one hand, the present disclosure takes into account that as the power of the wind turbine continues to increase, the diameter of the wind turbine impeller also gradually increases, and the electrical torque of the wind turbine also increases. When running under load, especially running under high-power load, an emergency stop and disconnection control method is usually adopted for power outage conditions. However, this control method will cause a large extreme load impact on the mechanical components of the wind turbine, such as the blades and tower. The large blade root impact load or tower bottom bending moment load will pose a major safety hazard to the wind turbine, and in severe cases will lead to risks such as blade breakage. In order to deal with this risk, the above risks are usually avoided by increasing the strength of the blades and tower. However, adopting these methods will increase the cost of the wind turbine.

[0030] On the other hand, the present disclosure takes into account that during the operation of wind turbines with load, especially high power load, in order to avoid overlap with the high voltage ride-through function (i.e., high voltage ride-through function), the threshold value for detecting power failure of the power grid is usually set higher than the required range of the high voltage ride-through curve. Therefore, after the power grid fails, an overvoltage shock at the grid-connected end is inevitable. In severe cases, it will cause failure of hardware such as pitch control equipment and lightning protection. The voltage waveform at the time of power failure is as follows: Figure 1 shown.

[0031] In order to solve the problems of load shock caused by emergency shutdown and grid-connected end overvoltage shock caused by power outage during wind turbine operation, this paper proposes a wind turbine control method, which controls the wind turbine grid-connected end voltage within the design target range during the power outage, thereby ensuring hardware safety. At the same time, it controls the wind turbine to maintain torque output for a period of time after the power outage to provide load support and reduce the extreme load shock of components such as blades and towers, thereby reducing the design cost of the wind turbine. Figures 2 to 6 Provide detailed explanation.

[0032] Figure 2 A flow chart illustrating a method for controlling a wind turbine generator system according to an exemplary embodiment of the present disclosure is shown.

[0033] As an exemplary embodiment, the control method of the wind turbine generator set according to the exemplary embodiment of the present disclosure can be applied to a doubly-fed wind turbine generator set. Figure 3 As shown, the generator stator of a doubly-fed wind turbine generator set is connected to the grid-connected terminal of the wind turbine generator set; the generator rotor is connected to the grid-connected terminal via a converter (specifically, including a machine-side converter and a grid-side converter). Specifically, the generator rotor is connected to the AC terminal of the machine-side converter, the DC terminal of the machine-side converter is connected to the DC terminal of the grid-side converter, and the AC terminal of the grid-side converter is connected to the grid-connected terminal. The grid-connected terminal is connected to the power grid via a single-chassis transformer (hereinafter referred to as a single-chassis transformer), a switchgear (e.g., a dropout switch), and other equipment.

[0034] Reference Figure 2 In step S101, it is monitored whether a grid power failure occurs in which the grid-connected end of the wind turbine generator set is disconnected from the grid.

[0035] It should be understood that a power outage can also be described as a power grid open circuit, a power grid disconnection, a power grid voltage loss, a power grid voltage drop to zero, etc. The power grid power outage fault in the present disclosure includes a situation where the wind turbine loses the power grid voltage (i.e., loses the power supply voltage of the power grid voltage source) due to any fault or condition at the near end or the far end. For example, a power grid power outage fault may include: a remote tripping (or line open circuit) of a wind farm connected to the wind turbine, or a tripping of the high-voltage side of a proximal single-chassis transformer connected to the wind turbine or a disconnection of the drop switch (or line open circuit), or a tripping of the low-voltage side of a single-chassis transformer (or line open circuit), resulting in a power grid voltage outage.

[0036] As an exemplary embodiment, step S101 may include monitoring whether a grid power failure has occurred based on at least one of the following operating parameters of the wind turbine generator set: wind turbine grid power, grid-connected terminal current, grid-connected terminal voltage, grid-side converter current (i.e., rotor grid-side current), and DC bus voltage. It should be understood that other signals may also be used to identify whether a grid power failure has occurred. For example, additional detection equipment may be added to detect grid open circuit faults and transmit the detection signal to the wind turbine to identify the wind turbine's grid power failure.

[0037] As an exemplary embodiment, step S101 may include: in response to the power being higher than a power threshold X, the grid-connected terminal current being lower than a current threshold Y, and the grid-connected terminal voltage being higher than a voltage threshold Z, determining that a grid power failure has occurred. As an example, step S101 may include: Figure 4 As an example, the power threshold X, current threshold Y, and voltage threshold Z may be set according to actual conditions and specific requirements.

[0038] For example, based on the characteristics of a doubly-fed wind turbine, the greater the wind turbine power at the moment of a grid power outage, the higher the wind turbine port voltage (i.e., grid-connected voltage) after the grid power outage. The design value of the power threshold X can be determined based on the converter hardware's performance limitations; for example, its value can be set to x% Pn. Regarding the current threshold Y, due to the grid power outage, the wind turbine's output power cannot be fed into the grid. Therefore, after the grid power outage, the wind turbine's grid-connected current (i.e., grid-connected current) is close to 0A. Taking into account sampling deviation (e.g., sampling deviation of e%), the value of current threshold Y can be set to e% In. Regarding the voltage threshold Z, due to the grid power outage, the wind turbine's power cannot be delivered, which increases the wind turbine's grid-connected voltage. Therefore, after the grid power outage, the wind turbine's power cannot be delivered, and the accumulated energy increases the wind turbine's DC bus voltage, causing the grid-connected voltage generated by the wind turbine to rise. Considering that the voltage threshold Z needs to be decoupled from the high voltage ride-through threshold, the voltage threshold Z can be set higher than the upper limit of the high voltage ride-through threshold and lower than the wind turbine's hardware tolerance limit. Among them, Pn represents the rated power of the fan, In represents the rated current of the fan, and Un represents the rated voltage of the fan.

[0039] According to exemplary embodiments of the present disclosure, a method for rapidly identifying grid power outages in a doubly-fed wind turbine has been designed. By simultaneously determining power, grid voltage, and grid current, this method can quickly and accurately identify grid power outages in doubly-fed wind turbines. Rapid grid power outage identification facilitates rapid control of the wind turbine, improving operational reliability.

[0040] In step S102 , in response to detecting a grid power failure, the protection mode is switched to a grid power failure protection mode.

[0041] As an example, in response to detecting a power grid blackout fault, the protection mode is switched from the normal power generation operation protection mode to the power grid blackout fault protection mode.

[0042] In step S103 , in response to entering the grid power failure protection mode, the wind turbine generator set is controlled to remain in operation.

[0043] In step S104 , in response to entering the grid power failure protection mode for a first preset time period, the wind turbine generator set is controlled to shut down.

[0044] Compared to the prior art methods for handling emergency stops after a power outage, the present disclosure proposes controlling the wind turbine to remain in operation for a first preset duration after a power outage. Regarding the specific operation of the wind turbine after a power outage, as an exemplary embodiment, the step of controlling the wind turbine to remain in operation may include: controlling the grid-connected voltage to remain at a target voltage value, and controlling the generator output torque to remain at a target torque value. Specifically, the wind turbine is controlled with the grid-connected voltage and the generator output torque maintained at the target voltage value and the target torque value as control targets.

[0045] In addition, as an exemplary embodiment, the step of controlling the wind turbine generator set to be continuously in operation may also include: in response to the output torque of the generator being maintained at the target torque value for a duration reaching a third preset duration, controlling the generator to stop outputting the torque. As an example, the first preset duration t1 is longer than or equal to the third preset duration t3, that is, t1 ≥ t3. As an example, the third preset duration can be set based on the load reduction requirement for a power outage of the power grid. The load reduction requirement for a power outage of the power grid may refer to: blades, bearings and other mechanical components, how long the torque support needs to be maintained after the power outage to ensure load safety. It should be understood that the first preset duration and the third preset duration can be set according to actual conditions and specific needs.

[0046] As an exemplary embodiment, the target voltage value can be set based on the upper voltage limit that the hardware of the wind turbine can withstand and the voltage control requirements for power outages of the power grid. Specifically, the setting of the target voltage value needs to consider two aspects: 1. Hardware safety: such as the safety of equipment such as pitch devices and converters, that is, after the power grid is powered off, the voltage generated by the operation of the wind turbine cannot exceed the upper voltage limit that the hardware equipment of the wind turbine can withstand; 2. Control requirements: that is, the maximum voltage allowed to be output by the converter from a control perspective, which is limited by the DC bus voltage. Specifically, after the power grid is powered off, the DC bus voltage is generally maintained at U dc_grid_openAccording to the principle of space vector modulation of the converter, the line voltage peak of the AC voltage output on the machine side and the grid side of the converter cannot be higher than the DC bus voltage value, so that the converter can be in the linear control range. Therefore, the target voltage value cannot be higher than the DC bus voltage. When the DC bus voltage range is determined, the target voltage value can be calculated based on the DC bus voltage value U dc_grid_open Calculate the upper limit of the target voltage value. For example, the upper limit of the target voltage value can be U dc_grid_open / √3. Furthermore, considering that the target voltage value needs to be decoupled from the high voltage ride-through threshold, the target voltage value can be higher than the upper limit of the high voltage ride-through threshold. For example, the target voltage value can be set as a%Un, where Un represents the rated voltage of the wind turbine.

[0047] As an exemplary embodiment, the target torque value is set based on the upper limit of the current that the hardware of the wind turbine generator can withstand and the load reduction requirement for the power grid power failure. X It can be set to b%Tn, where Tn represents the rated torque of the fan.

[0048] On the one hand, the present disclosure proposes to control the grid-connected terminal voltage of the wind turbine at a target voltage value after the power grid is cut off, so as to avoid the risk of overvoltage failure of the wind turbine hardware; on the other hand, the present disclosure proposes to control the generator to continuously output a torque of controllable amplitude within a set time after the power grid is cut off. The electromagnetic torque output by the generator can balance the aerodynamic torque of the impeller, thereby quickly reducing the wind turbine speed and reducing the wind turbine load. If the emergency stop process is performed according to the existing technology, the generator torque will immediately drop to 0 after the power grid is cut off, that is, the generator has no electromagnetic torque and cannot balance the aerodynamic torque of the impeller. The impeller speed will accelerate, causing the blades to bear excessive load, and in severe cases, the blades will break.

[0049] With respect to the first aspect, as an exemplary embodiment, the step of controlling the grid-connected voltage to be continuously at a target voltage value may include: controlling the output voltage of the grid-side converter (i.e., the rotor grid-side voltage) and the reactive current output by the machine-side converter so that the grid-connected voltage is continuously at the target voltage value; or, controlling the output voltage of the grid-side converter and the reactive current output by the grid-side converter (requiring a larger power module capacity of the grid-side converter) so that the grid-connected voltage is continuously at the target voltage value; or, controlling the output voltage of the generator stator (the stator is connected to the grid-side converter, so they are the same voltage) and the reactive current output by the machine-side converter so that the grid-connected voltage is continuously at the target voltage value; or, controlling the output voltage of the generator stator and the reactive current output by the grid-side converter so that the grid-connected voltage is continuously at the target voltage value.

[0050] Regarding controlling the output voltage of the grid-side converter, it can be specifically controlled by controlling the modulation voltage of the grid-side converter (i.e., the operating voltage applied to the IGBT). As an example, the modulation voltage of the grid-side converter can be set to a constant value (i.e., always set to the target voltage value). As another example, the modulation voltage can be determined by tracking the target voltage value based on the real-time value of the grid-connected voltage using a PI controller. Regarding controlling the output voltage of the generator stator, it can be specifically controlled by controlling the modulation voltage of the machine-side converter. Regarding controlling the reactive current output by the machine-side converter, it refers to controlling the reactive current applied by the machine-side converter to the doubly fed generator. Because the grid-side converter is directly connected to the generator stator, the reactive current is emitted by the machine-side converter to achieve the modulation voltage target of the grid-side converter. As an example, the machine-side converter can be controlled by the reactive current target value. The reactive current target value is derived from the output of the grid-side modulation voltage controller. The machine-side converter can track the reactive current target value using a PI controller to emit reactive current. According to exemplary embodiments of the present disclosure, considering that the circuit portion formed by the generator rotor and its connected converter is physically connected in parallel with the generator stator, grid-connected voltage control can be achieved by controlling the voltage on either the grid-side converter or the generator stator side, and grid-connected voltage control can also be achieved by controlling the reactive power generation of either the grid-side converter or the generator-side converter. Specifically, by controlling the output voltage of the grid-side converter (or stator) and controlling the reactive current generation of the generator-side converter (or grid-side converter), the output voltage is stabilized, thereby maintaining the grid-connected voltage at a target voltage value.

[0051] Regarding the second aspect, as an exemplary embodiment, the step of controlling the output torque of the generator to be continuously at the target torque value may include: controlling the active current output by the machine-side converter and starting the braking resistor so that the output torque of the generator is continuously at the target torque value.

[0052] As an exemplary embodiment, the step of controlling the output torque of the generator to continuously maintain a target torque value may include: controlling the output torque of the generator to continuously maintain a target torque value via a converter controller. For example, in response to entering a power grid power failure protection mode, the converter controller may take over torque control of the wind turbine. This is primarily due to the significant delay associated with master control of the wind turbine (i.e., communication delay between the master control and the converter controller). The converter controller may directly set the torque setpoint at the target torque value while simultaneously controlling the braking resistor to consume a corresponding amount of power, thereby achieving energy consumption, i.e., implementing a constant torque control mode. For example, the braking resistor's startup voltage and stop voltage may be controlled to control the braking resistor's startup voltage. Furthermore, in addition to achieving a constant torque control mode after a power grid power failure by the converter alone and autonomously controlling the torque, constant torque control may also be achieved through a joint master control and converter. Specifically, in response to entering a power grid power failure protection mode, the master control transmits a constant torque setpoint (i.e., a target torque value) to the converter controller, and the converter maintains operation and executes the target torque value transmitted by the master control for a first predetermined period of time.

[0053] Compared to the prior art control method of using an emergency shutdown and disconnection method for power outage conditions, the present disclosure proposes that after detecting a power outage, the wind turbine remains in operation for a first preset time period. In order to ensure the safe operation of the wind turbine during this continuous operation period, the present disclosure designs a protection logic suitable for the continuous operation period after the power outage, which not only protects the hardware safety of the wind turbine during the continuous operation period, but also considers the load reduction requirements. As an exemplary embodiment, the control method of the wind turbine generator set according to the exemplary embodiment of the present disclosure may also include: in response to entering the power outage fault protection mode, monitoring whether the DC bus voltage is overvoltage and whether the converter current is overcurrent; in response to the DC bus voltage overvoltage or the converter current overcurrent, controlling the wind turbine generator set to shut down immediately or after a second preset time period, that is, in response to the DC bus voltage overvoltage or the converter current overcurrent, it will shut down in advance, rather than waiting for the first preset time period after entering the power outage fault protection mode.

[0054] As an example, the wind turbine generator set can be controlled to shut down in response to the DC bus voltage being higher than a first voltage threshold or the converter current being higher than a first current threshold. The wind turbine generator set can be controlled to shut down in response to the DC bus voltage being higher than a second voltage threshold but lower than the first voltage threshold for a second preset duration or the converter current being higher than a second current threshold but lower than the first current threshold for a second preset duration. As an example, the first preset duration t1 is longer than the second preset duration t2, i.e., t1>t2.

[0055] As an example, the current of the converter may specifically include the current of the machine-side converter and the current of the grid-side converter. Accordingly, monitoring whether the current of the converter is overcurrent may include: monitoring whether the current of the machine-side converter is overcurrent, and monitoring whether the current of the grid-side converter is overcurrent. The first current threshold may specifically include: a first machine-side current threshold and a first grid-side current threshold. The second current threshold may specifically include: a second machine-side current threshold and a second grid-side current threshold. As an example, the wind turbine generator set may be controlled to shut down in response to the DC bus voltage being higher than the first voltage threshold, or the current of the machine-side converter being higher than the first machine-side current threshold, or the current of the grid-side converter being higher than the first grid-side current threshold. As an example, in response to the DC bus voltage being higher than the second voltage threshold but not higher than the first voltage threshold for a second preset time period, or the current of the machine-side converter being higher than the second machine-side current threshold but not higher than the first machine-side current threshold for a second preset time period, or the current of the grid-side converter being higher than the second grid-side current threshold but not higher than the first grid-side current threshold for a second preset time period, the wind turbine generator set is controlled to shut down.

[0056] It should be understood that the second preset time and the above threshold can be set according to the safety and load reduction requirements of the wind turbine hardware (eg, power devices of the converter). As an example, the second preset time can be set to 0.1s.

[0057] Figure 5 A flow chart illustrating a method for controlling a wind turbine generator system according to another exemplary embodiment of the present disclosure is shown.

[0058] Reference Figure 5 , through the wind turbine grid-connected power, grid-connected voltage and grid-connected current, the grid power-off status during the wind turbine operation can be quickly identified and the grid power-off flag can be set.

[0059] Based on the characteristics of a power outage during wind turbine operation, after a power outage occurs, the system maintains continuous operation for a first preset duration. Specifically, upon identifying a power outage during wind turbine operation, the control mode of the grid-side converter is switched from a conventional power generation control mode to a grid-connected voltage control mode, thereby controlling the grid-connected voltage amplitude after the power outage to within a target design value. Furthermore, upon identifying a power outage during wind turbine operation, the control mode of the generator-side converter is switched from a conventional power generation control mode to a constant torque control mode, thereby continuously outputting a controllable torque amplitude for a set time after the power outage.

[0060] Figure 6 A structural block diagram of a control device for a wind turbine generator system according to an exemplary embodiment of the present disclosure is shown.

[0061] Reference Figure 6According to an exemplary embodiment of the present disclosure, the control device of a wind turbine generator set includes: a fault monitoring unit 101 , a mode switching unit 102 , an operation control unit 103 , and a shutdown control unit 104 .

[0062] Specifically, the fault monitoring unit 101 is configured to monitor whether a grid power failure occurs in which the grid-connected terminal of the wind turbine generator set is disconnected from the grid.

[0063] The mode switching unit 102 is configured to switch the protection mode to the grid power failure protection mode in response to detecting the occurrence of a grid power failure.

[0064] The operation control unit 103 is configured to control the wind turbine generator set to remain in an operating state in response to entering the grid power failure protection mode.

[0065] The shutdown control unit 104 is configured to control the wind turbine generator set to shut down in response to entering the grid power failure protection mode for a first preset time period.

[0066] As an exemplary embodiment, the shutdown control unit 104 can also be configured to: in response to entering the grid power failure fault protection mode, monitor whether the DC bus voltage is overvoltage and whether the current of the converter is overcurrent; in response to the DC bus voltage being higher than the first voltage threshold or the current of the converter being higher than the first current threshold, control the wind turbine generator set to shut down; in response to the DC bus voltage being higher than the second voltage threshold and not higher than the first voltage threshold for a continuous period reaching a second preset period, or the current of the converter being higher than the second current threshold and not higher than the first current threshold for a continuous period reaching a second preset period, control the wind turbine generator set to shut down; wherein, the first preset period is longer than the second preset period.

[0067] As an exemplary embodiment, the operation control unit 103 may be configured to: control the grid-connected terminal voltage to be continuously at a target voltage value; and control the output torque of the generator to be continuously at a target torque value.

[0068] As an exemplary embodiment, the target voltage value may be set based on an upper voltage limit that the hardware of the wind turbine generator system can withstand and a voltage control requirement for a power grid blackout fault.

[0069] As an exemplary embodiment, the target torque value may be set based on an upper limit of current that the hardware of the wind turbine generator system can withstand and a load reduction requirement for a grid power failure.

[0070] As an exemplary embodiment, the converter of the wind turbine generator set includes: a machine-side converter and a grid-side converter; wherein the operation control unit 103 can be configured to: control the output voltage of the grid-side converter and the reactive current output by the machine-side converter, so that the grid-connected terminal voltage is continuously at a target voltage value; or, control the output voltage of the grid-side converter and the reactive current output by the grid-side converter, so that the grid-connected terminal voltage is continuously at a target voltage value; or, control the output voltage of the generator stator and the reactive current output by the machine-side converter, so that the grid-connected terminal voltage is continuously at a target voltage value; or, control the output voltage of the generator stator and the reactive current output by the grid-side converter, so that the grid-connected terminal voltage is continuously at a target voltage value.

[0071] As an exemplary embodiment, the converter of the wind turbine generator set includes: a machine-side converter and a grid-side converter; wherein, the operation control unit 103 can be configured to: control the active current output by the machine-side converter and start the braking resistor so that the output torque of the generator is continuously at the target torque value.

[0072] As an exemplary embodiment, the operation control unit 103 can be configured to: in response to the output torque of the generator being maintained at the target torque value for a duration reaching a third preset duration, control the generator to stop outputting the torque; wherein the first preset duration is longer than or equal to the third preset duration, and the third preset duration is set based on the load reduction requirement for a power grid power failure.

[0073] As an exemplary embodiment, the operation control unit 103 may be configured to control the output torque of the generator to continuously be at a target torque value through the current converter controller.

[0074] As an exemplary embodiment, the fault monitoring unit 101 may be configured to determine that a grid power failure occurs in response to power being higher than a power threshold, grid-connected current being lower than a current threshold, and grid-connected voltage being higher than a voltage threshold.

[0075] It should be understood that the specific processing performed by the control device of the wind turbine generator set according to the exemplary embodiment of the present disclosure has been referred to. Figures 2 to 5 The details are described in detail and will not be repeated here.

[0076] It should be understood that the various units in the control device of the wind turbine generator system according to the exemplary embodiments of the present disclosure may be implemented as hardware components and / or software components. Those skilled in the art may implement the various units using, for example, a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), depending on the processing performed by the defined various units.

[0077] A controller for a wind turbine generator set according to an exemplary embodiment of the present disclosure includes a processor (not shown) and a memory (not shown). The memory stores a computer program that, when executed by the processor, causes the processor to execute the wind turbine generator set control method described in the exemplary embodiment above. For example, the controller may include a main control and / or converter controller for the wind turbine generator set.

[0078] According to an exemplary embodiment of the present disclosure, a computer-readable storage medium storing instructions may also be provided, wherein when the instructions are executed by at least one processor, the at least one processor is prompted to execute the control method of the wind turbine generator set as described in the above exemplary embodiment. Examples of computer-readable storage media here 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, non-volatile 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, multimedia card, secure digital (SD) card or ultra-fast 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, any other device 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. The computer program in the above-mentioned computer-readable storage medium can be run in an environment deployed in a computer device such as a client, a host, an agent device, a server, etc. In addition, in one example, the computer program and any associated data, data files and data structures are distributed on a networked computer system so 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.

[0079] According to an exemplary embodiment of the present disclosure, a computer program product may be provided. Instructions in the computer program product may be executed by at least one processor to implement the control method of the wind turbine generator set as described in the above exemplary embodiment.

[0080] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the claims.

[0081] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A control method for a wind turbine generator set, characterized in that: include: Monitor whether a power outage occurs where the grid-connected end of the wind turbine generator is disconnected from the grid; In response to detecting a power grid power failure, switching the protection mode to a power grid power failure protection mode; In response to entering the grid power failure protection mode, controlling the wind turbine generator set to remain in an operating state; In response to entering the grid power failure protection mode for a first preset time period, controlling the wind turbine generator set to shut down; The steps of controlling the wind turbine generator set to remain in a continuous operating state include: Control the grid-connected voltage to remain at the target voltage value; Controlling the output torque of the generator to continuously maintain a target torque value; Among them, the target voltage value is set based on the upper limit of the voltage that the hardware of the wind turbine generator set can withstand and the voltage control requirement for power grid power failure; the target torque value is set based on the upper limit of the current that the hardware of the wind turbine generator set can withstand and the load reduction requirement for power grid power failure.

2. The control method according to claim 1, characterized in that: Also includes: In response to entering the grid power failure protection mode, monitoring whether the DC bus voltage is overvoltage and whether the converter current is overcurrent; In response to the DC bus voltage being higher than a first voltage threshold or the converter current being higher than a first current threshold, controlling the wind turbine generator set to shut down; In response to the DC bus voltage being higher than the second voltage threshold but not higher than the first voltage threshold for a continuous period reaching a second preset period, or the converter current being higher than the second current threshold but not higher than the first current threshold for a continuous period reaching a second preset period, controlling the wind turbine generator set to shut down; The first preset duration is longer than the second preset duration.

3. The control method according to claim 1, wherein: The converter of the wind turbine generator set includes: a machine-side converter and a grid-side converter; wherein the step of controlling the grid-connected terminal voltage to continuously be at a target voltage value includes: By controlling the output voltage of the grid-side converter and the reactive current output by the generator-side converter, the grid-connected voltage is kept at the target voltage value. Alternatively, the grid-connected terminal voltage is maintained at a target voltage value by controlling the output voltage of the grid-side converter and the reactive current output by the grid-side converter; Alternatively, the grid-connected voltage is maintained at the target voltage value by controlling the output voltage of the generator stator and the reactive current output by the generator-side converter; Alternatively, the grid-connected voltage is maintained at the target voltage value by controlling the output voltage of the generator stator and the reactive current output by the grid-side converter.

4. The control method according to claim 1, wherein: The converter of the wind turbine generator set includes: a generator-side converter and a grid-side converter; wherein the step of controlling the output torque of the generator to continuously be at a target torque value includes: By controlling the active current output by the machine-side converter and starting the braking resistor, the output torque of the generator is kept at the target torque value.

5. The control method according to claim 1, characterized in that: The steps of controlling the wind turbine generator set to remain in operation also include: In response to the generator output torque being maintained at the target torque value for a duration reaching a third preset duration, controlling the generator to stop outputting torque; The first preset time period is longer than or equal to the third preset time period, and the third preset time period is set based on a load reduction requirement for a power grid power failure.

6. The control method according to claim 1, characterized in that: The steps of controlling the output torque of the generator to continuously be at the target torque value include: The output torque of the generator is controlled by the converter controller to maintain the target torque value.

7. The control method according to claim 1, characterized in that: The steps of monitoring whether a grid power failure occurs in which the grid-connected terminal of the wind turbine generator is disconnected from the grid include: In response to the power being higher than a power threshold, the grid-connected terminal current being lower than a current threshold, and the grid-connected terminal voltage being higher than a voltage threshold, it is determined that a grid blackout fault occurs.

8. A control device for a wind turbine generator set, characterized in that: include: a fault monitoring unit configured to monitor whether a grid power failure occurs in which the grid-connected terminal of the wind turbine generator set is disconnected from the grid; a mode switching unit configured to switch the protection mode to a power grid power failure protection mode in response to detecting a power grid power failure; an operation control unit, configured to control the wind turbine generator set to remain in an operation state in response to entering a power grid power failure protection mode; a shutdown control unit, configured to control the wind turbine generator set to shut down in response to entering the grid power failure protection mode for a first preset time period; The operation control unit is configured as follows: Control the grid-connected voltage to remain at the target voltage value; Controlling the output torque of the generator to continuously maintain a target torque value; Among them, the target voltage value is set based on the upper limit of the voltage that the hardware of the wind turbine generator set can withstand and the voltage control requirement for power grid power failure; the target torque value is set based on the upper limit of the current that the hardware of the wind turbine generator set can withstand and the load reduction requirement for power grid power failure.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the processor is prompted to execute the control method for a wind turbine generator system according to any one of claims 1 to 7.

10. A controller for a wind turbine generator set, characterized in that: The controller includes: processor; The memory stores a computer program, which, when executed by a processor, prompts the processor to execute the control method for a wind turbine generator set according to any one of claims 1 to 7.

11. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the control method for a wind turbine generator set according to any one of claims 1 to 7 is implemented.

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