Control method of wind generating set, computer readable storage medium and controller

Abstract

The invention provides a control method of a wind generating set, a computer readable storage medium and a controller. The control method can comprise the steps that the current rotating speed of a generator of the wind generating set is obtained; in response to the fact that the current rotating speed of the generator is within a first preset rotating speed range and the current initial torque given value used for controlling a machine-side converter of the wind generating set is larger than the rated torque of the generator, the current initial torque given value is decreased to be first torque, and the first torque serves as a given value to be used for torque PI control of the machine-side converter; the lower limit value of the first preset rotating speed range is greater than the rated rotating speed of the generator.

Description

Technical Field

[0001] The present application relates to the field of wind power, and more specifically, to a control method, a computer-readable storage medium, and a controller for a wind turbine generator set. Background Art

[0002] In a wind turbine generator set (referred to as a wind turbine or set), the wind turbine converter is a key component connecting the generator and the grid. It is responsible for converting the variable frequency AC generated by the generator into a fixed frequency AC for grid connection. The converter usually includes a machine-side converter and a grid-side converter, which are connected through a DC bus.

[0003] When the wind turbine is running, the control system calculates the ideal torque set value based on wind speed, generator speed and other factors, and sends it to the wind turbine converter. The torque command corresponding to the torque set value is used to control the output power of the generator to ensure that the wind turbine can operate safely and efficiently.

[0004] However, in some cases, such as when encountering gusts under overspeed conditions, the control system (e.g., the main controller) may issue a maximum torque command that exceeds what the current conditions can handle. This excessive torque command may cause the apparent current of the machine-side converter to exceed its designed maximum range. For generators using a deep magnetic weakening control strategy, this control method aims to extend the speed range of the generator while keeping the magnetic field strength at a low level to improve efficiency. However, if excessive torque is applied in this state, it may cause control system instability, which in turn causes current oscillations, the control system of the machine-side converter (e.g., the machine-side converter controller) to become unstable, and the generator output torque to fluctuate, which in turn affects the speed of the wind turbine and causes it to oscillate. This phenomenon not only affects the quality and stability of power production, but may also cause wind turbine failures and shutdowns. Summary of the invention

[0005] In order to solve at least one of the above technical problems, the present disclosure provides a control method for a wind turbine generator set.

[0006] One of the objectives of the present disclosure is to provide a control method capable of preventing speed oscillation under overspeed conditions.

[0007] One of the objectives of the present disclosure is to provide a control method capable of reducing machine-side current and weak magnetic current.

[0008] According to a first aspect of the present disclosure, a control method for a wind turbine generator set is provided, the control method comprising: acquiring a current rotational speed of a generator of the wind turbine generator set; in response to the current rotational speed of the generator being within a first preset rotational speed range and the current initial torque given value for controlling a machine-side converter of the wind turbine generator set being greater than the rated torque of the generator, reducing the current initial torque given value to a first torque, and using the first torque as a given value for torque PI control of the machine-side converter to control the machine-side converter, wherein a lower limit value of the first preset rotational speed range is greater than the rated speed of the generator.

[0009] According to an embodiment of the present disclosure, the current initial torque set value is the initial torque set value received by the controller of the machine-side converter of the wind turbine generator set, and the control method may further include: controlling the machine-side converter by torque PI control with the first torque as the set value.

[0010] According to an embodiment of the present disclosure, through torque PI control with a first torque as a given value, the step of controlling the machine-side converter may include: performing PI control on the difference between the first torque and the feedback torque calculated based on the current of the generator to obtain a q-axis current reference value; performing PI control on the difference between the q-axis current reference value and the q-axis current calculated based on the current of the generator to obtain a first q-axis voltage. The control method also includes: performing PI control on the difference between the rated voltage of the generator and the feedback voltage of the generator port to obtain a d-axis current reference value; performing PI adjustment on the difference between the d-axis current reference value and the d-axis feedback current calculated based on the current of the generator to obtain a first d-axis voltage; and obtaining a control signal for controlling the machine-side converter based on the first d-axis voltage and the first q-axis voltage.

[0011] According to an embodiment of the present disclosure, the step of reducing the current initial torque setting to the first torque may include: gradually reducing the current initial torque setting value to the first torque according to a preset slope.

[0012] According to an embodiment of the present disclosure, the first torque may be a ratio of a rated power of the generator to a current rotation speed.

[0013] According to an embodiment of the present disclosure, the control method may further include: in response to the current speed of the generator dropping from a first preset speed range to less than a lower limit value, or the current initial torque given value being less than or equal to the rated torque of the generator, adjusting the first torque to a second torque according to a preset slope, wherein the second torque is the ratio of the rated power of the generator to the current speed of the generator.

[0014] According to an embodiment of the present disclosure, the over-speed torque limit flag can be reset in response to the current speed of the generator dropping from a first preset speed range to less than a lower limit value, or the current initial torque given value being less than or equal to the rated torque of the generator; the torque recovery flag can be set in response to detecting a falling edge of the over-speed torque limit flag, and the first torque can be adjusted to the second torque according to a preset slope.

[0015] According to an embodiment of the present disclosure, the lower limit value of the first preset speed range may be greater than or equal to 1.05 times the rated speed.

[0016] According to an embodiment of the present disclosure, the wind turbine generator set may be a DC wind turbine generator set.

[0017] According to a second aspect of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a program or an instruction, and when the program or the instruction is executed by a processor, the processor is prompted to execute the above control method.

[0018] According to a third aspect of the present disclosure, a controller of a wind turbine generator set is provided, the controller comprising a memory and a processor, the memory storing a program or instruction, and when the program or instruction is executed by the processor, the processor is prompted to execute the above control method.

[0019] The control method according to the embodiment of the present disclosure can reduce the damage and fatigue of the large components of the unit and increase the service life of the large components of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flowchart illustrating a control method according to the first embodiment of the present disclosure.

[0021] Figure 2 is a flowchart illustrating a control signal generation process according to an embodiment of the present disclosure.

[0022] Figure 3 is a flowchart illustrating a control method according to a second embodiment of the present disclosure.

[0023] Figure 4 is a control block diagram of a converter with an overspeed torque limiting function according to an embodiment of the present disclosure.

[0024] Figure 5 is a system block diagram showing a DC wind turbine generator set according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] The following detailed description is provided to help gain a comprehensive understanding of the methods, devices and / or systems described herein. However, the order of operations described herein is only an example and is not limited to those orders set forth herein, but may be equivalently replaced or changed except for operations that must occur or be performed in a specific order. In addition, for greater clarity and simplicity, the description of content known in the art will be omitted or simplified.

[0026] 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.

[0027] Unless otherwise specified, the same reference numerals generally refer to the same elements (e.g., components, steps, and methods). Reference numerals described in the previous embodiments may be omitted if they appear again in the subsequent embodiments. In addition, the technical features described in different or the same embodiments may be combined in any manner, as long as the combined embodiments or technical solutions are complete and can solve the technical problems of the present application or achieve the technical effects described or not described in the present disclosure but can be determined based on the above complete technical solutions. The terms used in the present disclosure are explained below.

[0028] DC wind turbine: A wind power device that converts wind energy into electrical energy, characterized in that the generated electricity is mainly output in the form of direct current (DC), that is, it can convert the alternating current generated by the generator into direct current, and can directly output direct current to meet the needs of various loads. DC wind turbines are generally suitable for application scenarios that require a DC power supply, such as powering a DC microgrid, a battery energy storage system, or other DC loads. The control method disclosed in the present invention may be applicable to a DC wind turbine, however, this is only an example, and the control method disclosed in the present invention may also be applicable to other types of wind turbines.

[0029] The present invention discloses an overspeed torque limiting strategy in the control strategy of the wind turbine converter. When the generator speed reaches the overspeed condition, the torque setting is limited so that the machine-side converter current operates within the maximum current allowable range, thereby ensuring the stable operation of the generator under the overspeed condition, avoiding the state of deep magnetic weakening, and avoiding low-frequency oscillation of the generator speed.

[0030] According to an embodiment of the present disclosure, the control method may include: obtaining the current speed of the generator of the wind turbine generator set; in response to the current speed of the generator being within a first preset speed range and the current initial torque given value for controlling the machine-side converter of the wind turbine generator set being greater than the rated torque of the generator, reducing the current initial torque given value to a first torque. The first torque here is used as a given value for the torque PI control of the machine-side converter to control the machine-side converter. The lower limit value of the first preset speed range is greater than the rated speed of the generator. For example, the lower limit value of the first preset speed range may be greater than or equal to 1.05 times the rated speed, and the upper limit value of the first preset speed range is not specifically limited.

[0031] The current initial torque setting value for controlling the machine-side converter of the wind turbine generator set may be a torque control instruction to be sent to the machine-side converter controller, or may be the current initial torque setting value received by the machine-side converter from the wind turbine master controller.

[0032] The control method according to the embodiment of the present disclosure can be implemented by a machine-side converter controller, that is, the logic judgment and control algorithm are completed inside the machine-side converter controller. The machine-side converter controller can determine whether the generator has reached an overspeed condition, and adjust the operating parameters, such as limiting the torque set value, when receiving an over-torque command.

[0033] The control method according to the embodiment of the present disclosure may be implemented by a main controller. As an example, the main controller may execute corresponding logical judgments and steps of limiting a torque given value, and send the limited torque given value to the machine-side converter controller.

[0034] The control method according to the embodiment of the present disclosure can be implemented by both the machine-side converter and the main controller. As an example, the main controller can send the limited initial torque given value to the machine-side converter controller, and the machine-side converter controller can perform subsequent torque control according to the limited initial torque given value. However, the implementation of the control method of the present disclosure is not limited to this. The following description is made by taking the control method according to the embodiment of the present disclosure implemented by the converter controller as an example.

[0035] Figure 1 is a flowchart showing a control method according to a first embodiment of the present disclosure, Figure 2 is a flowchart showing a control signal generation process according to an embodiment of the present disclosure, Figure 3 is a flowchart showing a control method according to a second embodiment of the present disclosure, Figure 4 is a control block diagram of a converter with an overspeed torque limiting function according to an embodiment of the present disclosure.

[0036] Reference Figure 1, the control method according to the first embodiment of the present disclosure may include step S110 , step S120 , step S130 , step S140 and step S150 .

[0037] In step S110, the current rotation speed of the generator of the wind turbine generator set is obtained.

[0038] As an example, the current speed of the generator can be obtained from the sensor of the wind turbine generator set. For example, the current speed can be measured by a sensor (such as an encoder) installed on the generator shaft, thereby receiving the speed information of the generator from the sensor. As an example, the current speed of the generator of the wind turbine generator set can also be estimated based on other monitored information, for example, the current speed of the generator of the wind turbine generator set can be estimated by measuring the wind speed, however, this is only an example, and the method of obtaining the current speed of the generator of the wind turbine generator set disclosed in the present invention is not limited to this.

[0039] In step S120, it is determined whether the current speed is within a preset speed range. The preset speed range here may be the first preset speed range as described above. As described above, the present disclosure performs corresponding torque limitation in the case of overspeed. The first preset speed range of the present disclosure may be used to determine whether the speed of the generator is overspeeding. The lower limit value of the first preset speed range may be greater than the rated speed of the generator. The rated speed of the generator is the maximum speed at which the generator is designed and expected to be able to operate stably for a long time. The rated speed of the generator may be determined based on the design parameters of the generator, the power output requirements, and the requirements for connection to the power grid or load. When the generator operates at its rated speed, it can provide rated power and maintain efficient performance and a long service life.

[0040] The lower limit value of the first preset speed range may be greater than the rated speed, for example, the lower limit value of the first preset speed range may be 1.05 times the rated speed, for example, the lower limit value of the first preset speed range may be greater than or equal to 1.1 times the rated speed, where 1.05 times the rated speed or 1.1 times the rated speed may be within the fluctuation range of the rated speed, in other words, the torque limiting operation may be performed when the fluctuation range of the rated speed is exceeded. The upper limit value of the first preset speed range is not subject to specific restrictions, and may be the maximum speed that the wind turbine generator set may have in order to maintain the rated power output. Although not shown, in the case where the wind turbine generator set continues to increase to exceed the preset speed (1.15 times the rated speed), the wind turbine generator set may be controlled to shut down. The overspeed torque limiting control strategy disclosed in the present invention may be applicable to overspeed conditions of 1.05 times the rated speed to 1.15 times the rated speed.

[0041] In step S130 , in response to the current rotation speed being within the preset rotation speed range, it is further determined whether the current initial torque setting is greater than the rated torque.

[0042] For example, in response to the current speed being greater than 1.05 times the rated speed, it is further determined whether the current initial torque setting is greater than the rated torque. In other words, the present disclosure can perform torque limiting control in the case of overspeed. The power P, the speed ω and the torque T can satisfy the following equation (1):

[0043] P=T×ω (1)

[0044] The rotation speed of the generator can be expressed in revolutions per minute (RPM) or in radians per second (rad / s). When the rotation speed of the generator is expressed in revolutions per minute, the above formula (1) can be transformed accordingly.

[0045] In step S140 , in response to the current initial torque setting or the current initial torque setting value being greater than the rated torque, the current initial torque setting value is reduced to the first torque.

[0046] In step S150, in response to the current rotation speed being outside the preset rotation speed range, for example, when the current rotation speed is within the fluctuation range of the rated rotation speed, the wind turbine generator set may be controlled in the original manner.

[0047] As an example, when the current speed is within the fluctuation range of the rated speed, the wind turbine generator set can be controlled in the original way without performing overspeed torque control. As an example, the above control method can be used to ensure that the wind turbine generator set outputs rated power or to ensure the rated power of the generator. The "original method" here refers to an existing control method that does not specifically take overspeed protection measures, which may specifically include control steps such as power regulation to optimize energy capture and maintain stable power output. As long as the speed remains within the preset range, these control steps are sufficient to ensure the normal operation of the unit.

[0048] As described above, the current initial torque set value may be the initial torque set value received by the controller of the machine-side converter of the wind turbine generator set. The control method according to an embodiment of the present disclosure may include controlling the machine-side converter by torque PI control with the first torque as the set value.

[0049] As an example, a double closed-loop active loop and a reactive loop may be used to implement specific control, and the outer loop of the double closed-loop of the active loop may be a torque loop, and the inner loop may be an active current loop.

[0050] The control method according to the embodiment of the present disclosure may also include active outer loop torque PI control and inner loop active current PI control with the first torque as a given value. In addition, the control method according to the embodiment of the present disclosure may also include reactive outer loop PI control and inner loop reactive current PI control with the rated voltage as a given value, the q-axis voltage may be obtained through active double closed-loop PI control, the d-axis voltage may be obtained through reactive double closed-loop PI control, and the control method according to the embodiment of the present disclosure may obtain the control signal of the machine-side converter according to the d-axis voltage and the q-axis voltage.

[0051] Specifically, through torque PI control with the first torque as a given value, the step of controlling the machine-side converter may include: performing PI control on the difference between the first torque and the feedback torque calculated based on the current of the generator to obtain a q-axis current reference value; performing PI control on the difference between the q-axis current reference value and the q-axis current calculated based on the current of the generator to obtain a first q-axis voltage.

[0052] Reference Figure 2 , the control method according to the embodiment of the present disclosure may further include step S141, step S142 and step S143.

[0053] In step S141, the difference between the rated voltage of the generator and the feedback voltage at the generator port is subjected to PI control to obtain a d-axis current reference value. The feedback voltage at the generator port can be measured by a voltage sensor or the like, or estimated by the electromagnetic characteristics of the motor, however, the present disclosure is not limited thereto. The rated voltage of the generator can be its own parameter.

[0054] In step S142 , a PI adjustment is performed on a difference between a d-axis current reference value and a d-axis feedback current calculated based on the current of the generator to obtain a first d-axis voltage.

[0055] In step S143 , a control signal for controlling the generator-side converter is obtained based on the first d-axis voltage and the first q-axis voltage.

[0056] Specifically, the step of obtaining a control signal for controlling the machine-side converter based on the first d-axis voltage and the first q-axis voltage may include loading the first d-axis voltage and the first q-axis voltage into an SVPWM (space vector pulse width modulation) module after coordinate transformation, and the SVPWM module may generate a control signal according to the voltage after coordinate transformation. Figure 4 The overspeed torque limiting operation and the specific control steps after the overspeed torque limiting operation are described.

[0057] For details, please refer to Figure 4 , a double closed loop active loop and reactive loop can be used to realize the control of the machine-side converter. The outer loop in the double closed loop of the active loop can be a torque loop, and the inner loop is an active current loop.

[0058] As described above, the torque loop setting (i.e., the current initial torque setting value) can be the torque setting T issued by the fan master control. e * After the over-speed torque limiting operation, the final torque setting is obtained. The specific process of the over-speed torque limiting operation and the over-speed torque limiting operation can be described as above and will not be repeated here.

[0059] Reference Figure 4 , the final torque setting and the torque loop feedback T e The active current loop given i is obtained by PI regulation. q * , the feedback of the torque loop T e According to the detected generator current I A ,I B ,I C Perform calculations.

[0060] As an example, the torque loop feedback T can be calculated by the following formula 2 e .

[0061]

[0062] Among them, T e is the feedback of the torque loop or the electromagnetic torque of the generator, p is the number of generator pole pairs, λ f is the magnetic flux generated by the permanent magnet, i q and i d are the d-axis current and the q-axis current, L d and L q The number of generator pole pairs, the magnetic flux generated by the permanent magnet, the d-axis inductance, and the q-axis inductance can be determined by the generator's own parameters or by testing. The d-axis current and the q-axis current can be determined based on the three-phase output current I of the generator winding. A ,I B ,I C After CLARK (3s / 2s) and PARK (2s / 2r) transformation, the torque loop feedback T is calculated. e The method is not limited to this. For example, the torque loop feedback T can be calculated by simplifying the calculation method in formula (2): e , for example, we can let L d =L q , in formula (2) and L d -L q The associated cross-coupling terms may be zero.

[0063] Active current loop feedback q The three-phase output current I A ,I B ,IC After CLARK (3s / 2s) and PARK (2s / 2r) transformation, the generator rotor position angle θ and speed ω required for PARK transformation can be obtained by a rotor position and speed calculation module, where the rotor position and speed calculation module may include a phase-locked loop (PLL). As an example, the rotor position and speed calculation module may be based on I A ,I B ,I C The current I in the static coordinate system obtained by CLARK (3s / 2s) α and I β The generator rotor position angle or phase angle θ and speed ω are obtained.

[0064] Reference Figure 4 , the active current loop is given by i q * and feedback q The output after PI regulation is added with the feedforward decoupling term ωLi d +ωψ f (ω is the angular velocity of the generator, L is the inductance of the generator winding, and ψf is the flux linkage of the generator permanent magnet) The first q-axis voltage can be obtained. The feedforward decoupling term here is only an example, and the feedforward decoupling term can be zero. The first q-axis voltage can be converted by 2r / 2s to obtain the output reference voltage given by u β .

[0065] The outer loop of the double closed loop of the reactive loop can be a weak magnetic loop, and the inner loop can be a reactive current loop. The given value of the weak magnetic loop is the rated voltage u of the motor. s * , the feedback voltage u of the weak magnetic ring s is the generator terminal voltage, the given u of the weak magnetic ring s * and feedback voltage u s After the difference is made, the reactive current loop given i is obtained through PI adjustment d * , reactive current loop feedback i d The three-phase output current I A ,I B ,I C After CLARK (3s / 2s) and PARK (2s / 2r) transformation, the position angle of the generator required for PARK transformation can be obtained by the rotor position and speed calculation module as mentioned above. d * and reactive current loop feedback i d The output obtained after PI regulation minus the feedforward decoupling term ωLi qThe first d-axis voltage can be converted into the output reference voltage u by 2r / 2s transformation. α The output reference voltage is given by u α and u β The driving signal S of the main circuit IGBT is obtained through the SVPWM module. a , S b , S c , driving signal S a , S b , S c It is the switching signal of the converter, which is used to control the switching state of the IGBT of the machine-side converter. As an example, the external input voltage of the SVPWM module can be the bus voltage u of the converter (for example, a DC fan converter) dc .

[0066] The active dual closed-loop control and reactive dual closed-loop control described above are merely examples, and the overspeed torque limiting scheme disclosed in the present invention may also be applicable to other control methods that require a given initial torque.

[0067] When the current initial torque setting is reduced to the first torque, the current initial torque setting may be reduced to the first torque in a stepwise reduction manner according to a certain slope.

[0068] As an example, the step of reducing the current initial torque setting to the first torque may include: gradually reducing the current initial torque setting value to the first torque according to a preset slope.

[0069] It can be known from the above formula (1) that in order to maintain the rated power generation, the greater the speed, the smaller the torque. When the initial torque given Tref is greater than the rated torque Tn, the current initial torque given value can be gradually reduced to the first torque according to a predetermined slope. The first torque can specifically be the ratio of the rated power of the generator to the current speed.

[0070] The slope of the decrease or the step size of each decrease step can be determined according to the action time or control cycle of the main controller and the control cycle of the converter controller.

[0071] The slope of overspeed torque limit and torque recovery should not be too large. Taking the control cycle of the main controller or the whole machine as 20ms and the control cycle of the converter controller as 200us as an example, a too large slope will have a greater impact on the speed of the unit and will aggravate the speed fluctuation. The slope of overspeed torque limit and torque recovery can be determined according to the ratio of the control cycle of the converter and the control cycle of the main controller. The slope of overspeed torque limit and torque recovery can be greater than the above ratio, so that the torque is limited or restored to the preset value within the time period corresponding to the control cycle of the main controller. Through the overspeed torque limit strategy, the converter torque setting is reduced and / or restored according to the preset slope. During the overspeed torque limit process in high wind conditions, the machine-side current is reduced and the weak magnetic current is reduced, thereby improving the stability of the machine-side converter controller, reducing speed fluctuations, and ensuring the reliable operation of the wind turbine generator set.

[0072] As an example, the control method according to an embodiment of the present disclosure also includes: in response to the current speed of the generator dropping from a first preset speed range to less than a lower limit value, or the current initial torque given value being less than or equal to the rated torque of the generator, adjusting the first torque to a second torque according to a preset slope, wherein the second torque is the ratio of the rated power of the generator to the current speed of the generator.

[0073] In other words, the torque setting can be increased from the first torque to the second torque according to a preset slope when the overspeed and overtorque conditions are not met. The slope in the torque recovery control can be the same as the slope in the torque limit control, and the slope can be variable in multiple converter control cycles corresponding to a single control cycle of the main controller. In order to make the action execution and response more timely and convenient, an overspeed torque limit flag and a torque recovery flag can be set.

[0074] As an example, in response to the current speed of the generator dropping from the first preset speed range to less than the lower limit value, or the current initial torque setting value being less than or equal to the rated torque of the generator, the overspeed torque limit flag may be reset (for example, the overspeed torque limit flag is reset to 0). In response to detecting the falling edge of the overspeed torque limit flag, the torque recovery flag may be set (for example, the torque recovery flag is set to 1), and the first torque may be adjusted to (for example, increased to) the second torque according to a preset slope.

[0075] For details, please refer to Figure 3 , the control method according to the second embodiment of the present disclosure may include steps S410, S411, step S420, step S430, step S440, step S450, step S460, step S470, step S480 and step S490.

[0076] In step S410, it is determined whether the current rotational speed is greater than a set threshold value k·Nn, where k can be 1.05 or 1.1, Nn is the rated rotational speed, and it is determined whether the reference torque Tref (i.e., the current initial torque given value) is greater than the set torque threshold value Tn (rated torque).

[0077] In step S420, in response to the above two conditions being met, the overspeed torque limit flag is set to 1, and the torque recovery flag is set to 0. In other words, when the controller or control system has detected that the speed and torque exceed the preset thresholds, it needs to make corresponding adjustments to protect the motor and the system.

[0078] In step S430, after the overspeed torque limit flag is set to 1 and the torque recovery flag is set to 0, the torque setting can be reduced to the torque value corresponding to the current speed (i.e., the rated power torque value) according to the preset slope. At different speeds, there may be different rated power torque values. Limiting the torque according to the preset slope can ensure that the torque adjustment is smooth and controllable, and avoid damage to the motor caused by sudden torque changes.

[0079] In step S440, it is determined whether the overspeed torque limit flag is 0. If the overspeed torque limit flag is 0, then in step S450, it is further determined whether a falling edge of the overspeed torque limit flag is detected.

[0080] In step S460 , if the falling edge is detected, the torque recovery flag is set to 1 or set to 1.

[0081] In step S470 , it may be determined whether the torque recovery flag is equal to 1.

[0082] In step S480, if the torque recovery flag is equal to 1, the torque setting can be restored from the overspeed limit value (i.e., the first torque) to the second torque according to the slope, where the second torque can be greater than the first torque and can be used as the current torque setting. In other words, the torque can be gradually restored to a normal value according to a preset slope to ensure that the motor can smoothly return to a normal working state.

[0083] In step S490, the torque recovery flag may be set to 0. That is, through the torque recovery control, the torque may be restored to the current torque setting, thereby controlling the wind turbine converter to operate normally.

[0084] As described above, after the overspeed torque limit flag is set to 1, the actual torque given of the DC converter decreases from the current value according to the preset slope to the torque corresponding to the rated power at the current speed. After the overspeed torque limit flag changes from 1 to 0, the torque recovery flag is set to 1 by detecting the falling edge of the overspeed torque limit. When the torque recovery flag is 1, the actual torque given of the DC converter is restored from the overspeed torque limit to the current torque given according to the set slope, and the torque recovery flag can be cleared to 0. Through the torque recovery flag and the overspeed torque limit flag, the implementation of the above-mentioned control method of the present disclosure can be made more reliable. The control method according to the embodiment of the present disclosure can be applied to DC wind turbines.

[0085] Figure 5 is a system block diagram showing a DC wind turbine generator set according to an embodiment of the present disclosure.

[0086] Reference Figure 5 , the fan impeller is connected to the permanent magnet synchronous generator through a mechanical transmission device (such as a gearbox). The permanent magnet synchronous generator converts mechanical energy into electrical energy. The AC power generated by the generator is converted into DC power through the fan converter. The fan converter not only realizes the conversion from AC to DC, but also controls the operating state of the generator to ensure the stable quality of the output power.

[0087] The wind turbine direct current converter includes a rectifier, and the output of the rectifier can further convert the direct current output by the wind turbine direct drive converter into direct current suitable for use by a load (e.g., hydrogen production equipment) through a DC / DC converter 1. Hydrogen production equipment usually requires specific voltage and current, and the DC / DC converter 1 can provide such customized power output to ensure the efficiency and stability of the hydrogen production process.

[0088] The hydrogen production equipment uses electric energy to generate hydrogen through water electrolysis or other methods, which can be used for fuel cells, chemical production and other purposes. The efficiency and stability of the hydrogen production equipment directly affect the energy efficiency of the entire system. In addition to the DC / DC converter 1, the wind turbine DC converter can also convert the DC power output by the wind turbine direct drive converter into DC power suitable for energy storage batteries through the DC / DC converter 2.

[0089] Energy storage batteries are used to store excess electrical energy for use when wind power is insufficient or demand is high. The DC / DC converter 2 can adjust the voltage and current to ensure that the battery charging and discharging process is safe and efficient. The energy storage battery is an energy storage unit in the system, which is used to store excess electrical energy generated by the wind power generation system. The battery can be a lithium-ion battery, lead-acid battery, or other type of energy storage device. The appropriate type is selected according to the specific needs of the system. The energy storage battery can not only improve the stability of the system, but also provide additional power support when the power grid is unstable or demand is high.

[0090] In addition to off-grid hydrogen production, the wind turbine generator set or DC wind turbine generator set to which the control method of the present disclosure is applied can also be used to meet other purposes of its own load or grid connection.

[0091] Each step of the above control method can be implemented by a corresponding software or hardware module or unit.

[0092] The above has been referred to Figures 1 to 5 A control method, a computer-readable storage medium, and a controller for a wind turbine generator set according to an exemplary embodiment of the present disclosure are described. However, it should be understood that the units, modules, and systems shown in the accompanying drawings may be configured as software, hardware, firmware, or any combination of the above items to perform specific functions. For example, these systems and devices may correspond to dedicated integrated circuits, pure software codes, or modules that combine software and hardware. In addition, one or more functions implemented by these systems or devices may also be uniformly performed by components in physical entity devices (e.g., processors, clients, or servers, etc.).

[0093] For example, according to an exemplary embodiment of the present disclosure, a computer-readable storage medium storing instructions may be provided, wherein when the instructions are executed by at least one computing device, the at least one computing device is prompted to perform at least one of the above steps.

[0094] It should be noted that the control method according to the exemplary embodiment of the present disclosure may rely on the execution of a computer program or instructions to implement the corresponding functions, that is, each device corresponds to each step in the functional architecture of the computer program, so that the entire system is called through a special software package (e.g., lib library) to implement the corresponding functions.

[0095] On the other hand, when the system, unit, or module is implemented in software, firmware, middleware, or microcode, the program code or code segment for performing the corresponding operation may be stored in a computer-readable medium such as a storage medium, so that at least one processor or at least one computing device may perform the corresponding operation by reading and running the corresponding program code or code segment. In addition, the computer-readable medium or storage medium may cause the processor to execute the above-mentioned control method when the computer program is executed by the processor.

[0096] For example, according to an exemplary embodiment of the present disclosure, a computer device including a readable medium storing computer program instructions may be provided, wherein the instructions, when executed by at least one computing device, prompt the at least one computing device to perform at least one of the above steps.

[0097] According to an exemplary embodiment of the present disclosure, an MMC controller may be provided. The MMC controller may include a memory and a processor. The memory stores instructions or programs. When the instructions or programs are executed by the processor, the processor is prompted to execute the above-mentioned control method, for example, at least one of the various steps of the above-mentioned control method may be executed.

[0098] The control method according to the embodiment of the present disclosure can prevent low-frequency speed oscillation under overspeed conditions.

[0099] The control method according to the embodiment of the present disclosure can reduce the machine-side current and the weak magnetic current.

[0100] The control method according to the embodiment of the present disclosure can reduce the damage and fatigue of the large components of the unit and increase the service life of the large components of the unit.

Claims

1. A control method for a wind turbine generator set, characterized in that: The control method comprises: Get the current speed of the generator of the wind turbine; In response to the current speed of the generator being within a first preset speed range and the current initial torque given value for controlling the machine-side converter of the wind turbine generator set being greater than the rated torque of the generator, the current initial torque given value is reduced to a first torque, and the first torque is used as a given value for torque PI control of the machine-side converter to control the machine-side converter, Wherein, the lower limit value of the first preset speed range is greater than the rated speed of the generator.

2. The control method of a wind turbine generator set according to claim 1, characterized in that: The current initial torque setting value is an initial torque setting value received by the controller of the machine-side converter of the wind turbine generator set. The control method further includes: controlling the machine-side converter by torque PI control with the first torque as a given value.

3. The control method of a wind turbine generator set according to claim 2, characterized in that: The step of controlling the generator-side converter by torque PI control with the first torque as a given value includes: performing PI control on a difference between the first torque and a feedback torque calculated based on the current of the generator to obtain a q-axis current reference value; performing PI control on a difference between the q-axis current reference value and a q-axis current calculated based on the current of the generator to obtain a first q-axis voltage, The control method also includes: performing PI control on the difference between the rated voltage of the generator and the feedback voltage of the generator port to obtain a d-axis current reference value; performing PI adjustment on the difference between the d-axis current reference value and the d-axis feedback current calculated based on the current of the generator to obtain a first d-axis voltage; and obtaining a control signal for controlling the machine-side converter based on the first d-axis voltage and the first q-axis voltage.

4. The control method of a wind turbine generator set according to claim 1, characterized in that: The step of reducing the current initial torque setting to the first torque includes: gradually reducing the current initial torque setting value to the first torque according to a preset slope.

5. The control method of a wind turbine generator set according to claim 4, characterized in that: The first torque is a ratio of the rated power of the generator to the current rotation speed.

6. The control method of a wind turbine generator set according to claim 1, characterized in that: The control method further comprises: In response to the current speed of the generator dropping from the first preset speed range to less than the lower limit value, or the current initial torque given value being less than or equal to the rated torque of the generator, the first torque is adjusted to a second torque according to a preset slope, wherein the second torque is the ratio of the rated power of the generator to the current speed of the generator.

7. The control method of a wind turbine generator set according to claim 6, characterized in that: In response to the current speed of the generator decreasing from the first preset speed range to less than the lower limit value, or the current initial torque setting value being less than or equal to the rated torque of the generator, resetting the overspeed torque limit flag; In response to detecting a falling edge of the overspeed torque limit flag, a torque recovery flag is set, and the first torque is adjusted to the second torque according to a preset slope.

8. The control method of a wind turbine generator set according to claim 1, characterized in that: The lower limit value of the first preset speed range is greater than or equal to 1.05 times the rated speed.

9. The control method of a wind turbine generator set according to any one of claims 1 to 8, characterized in that: The wind turbine generator set is a DC wind turbine generator set.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program or an instruction, which, when executed by a processor, causes the processor to execute the control method according to any one of claims 1 to 9.

11. A controller for a wind turbine generator set, characterized in that: The controller includes a memory and a processor, wherein the memory stores a program or an instruction, and when the program or the instruction is executed by the processor, the processor is prompted to execute the control method according to any one of claims 1 to 9.

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