CN108612624A - A method and device for controlling the speed of a wind power generator - Google Patents

Abstract

The invention discloses a method and a device for controlling the rotating speed of a wind driven generator, relates to the field of wind power generation, and aims to solve the problem that the wind driven generator is damaged by overspeed stop of the wind driven generator when wind conditions suddenly change. The rotating speed control method of the wind driven generator comprises the following steps: collecting wind speed; if the wind speed increasing degree is larger than a first preset wind speed change threshold value, keeping the electromagnetic torque of the wind driven generator at a fixed electromagnetic torque value, increasing the target pitch angle value of the wind driven generator, and performing the opening control according to the increased target pitch angle value; and if the detected wind speed reduction degree is greater than a second preset wind speed change threshold value, reducing the electromagnetic torque and the pitch angle of the wind driven generator, calculating a cut-out electromagnetic torque value according to the real-time rotating speed of the wind driven generator, and if the difference value between the real-time electromagnetic torque value and the cut-out electromagnetic torque value of the wind driven generator is smaller than the preset torque threshold value, controlling the rotating speed according to a preset rotating speed-pitch angle relation and a preset rotating speed-electromagnetic torque relation.

Description

A method and device for controlling the speed of a wind power generator

technical field

The invention relates to the field of wind power generation, in particular to a method and device for controlling the speed of a wind power generator.

Background technique

In the current situation of energy shortage, wind power, as a new energy source, has been widely used in various fields. Wind power generation is the use of wind generators to convert wind energy into electrical energy, and transmit the converted electrical energy to the grid, and then to various electrical equipment.

The speed of the wind generator in the wind power generator is related to the size of the wind force. The wind power can be reflected in the wind speed. The greater the wind speed, the faster the blades of the wind power generator rotate, which drives the faster the speed of the wind generator in the wind power generator. In order to ensure The rotation speed of the wind turbine is stable, and the pitch angle needs to be adjusted to adjust the rotation speed of the wind turbine. Under normal wind conditions, the wind speed changes relatively slowly, and the speed of the wind turbine rises or falls relatively slowly. In this case, the speed difference-pitch angle PID calculation is often used (that is, the speed difference-pitch angle Proportional, integral, and differential calculations), the appropriate pitch angle is obtained through the calculation of the speed difference, and then the blades of the wind turbine are adjusted. However, when the wind condition changes suddenly, such as when there is a gust of wind, the wind speed will suddenly increase. From obtaining the appropriate pitch angle value based on the speed difference-pitch angle PID calculation, to adjusting the pitch angle value based on the calculation. There is hysteresis in the paddle process. Due to the rapid change of wind speed, the pitch angle value calculated according to the previous moment is no longer suitable for the adjustment process of the next moment, and cannot effectively stabilize the speed of the wind turbine, which will cause the wind turbine to stop at an overspeed. There is even the possibility of damage to wind turbines.

Contents of the invention

Embodiments of the present invention provide a method and device for controlling the speed of a wind-driven generator, which can avoid shutdown of the wind-driven generator due to overspeed, thereby avoiding possible damage to the wind-driven generator.

In the first aspect, an embodiment of the present invention provides a method for controlling the speed of a wind power generator, including: collecting wind speed; if the wind speed becomes greater than a first preset wind speed change threshold, then maintaining the electromagnetic torque of the wind power generator at a fixed electromagnetic torque Torque value, and increase the target pitch angle value of the wind turbine, and use the increased target pitch angle value to perform propeller opening control; if it is detected that the wind speed becomes smaller than the second preset wind speed change threshold, then decrease The electromagnetic torque and pitch angle of the wind turbine, and calculate the cut-out electromagnetic torque value according to the real-time speed of the wind turbine, if the difference between the real-time electromagnetic torque value of the wind turbine and the cut-out electromagnetic torque value is less than the preset torque threshold , to control the speed according to the preset speed-pitch angle relationship and the preset speed-electromagnetic torque relationship.

With reference to the first aspect, in some embodiments, the fixed electromagnetic torque value is the real-time electromagnetic torque value at the moment when the wind speed is determined to increase more than the first preset wind speed change threshold.

With reference to the first aspect, in some embodiments, the process of controlling the pitch angle with the increased target pitch angle value further includes: calculating the corresponding pitch angle value according to the real-time rotational speed of the wind turbine; if the corresponding pitch angle value is If the pitch angle value is greater than the increased target pitch angle value, continue to increase the increased target pitch angle value.

In combination with the first aspect, in some embodiments, if it is detected that the degree of wind speed decrease is greater than the second preset wind speed change threshold, the step of reducing the electromagnetic torque and pitch angle of the wind turbine includes: if the wind speed is detected to decrease If the degree is greater than the second preset wind speed change threshold, the electromagnetic torque and the pitch angle of the wind generator are respectively reduced at the preset speed.

In combination with the first aspect, in some embodiments, when the difference between the real-time electromagnetic torque value of the wind turbine and the cut-out electromagnetic torque value is less than the preset torque threshold, the step of controlling the speed according to the preset speed-pitch angle relationship Including: if the difference between the real-time electromagnetic torque value of the wind turbine and the cut-out electromagnetic torque value is less than a preset threshold, the speed control is performed according to the preset speed-pitch angle PID relationship.

In a second aspect, an embodiment of the present invention provides a speed control device for a wind power generator, including: a wind speed acquisition unit configured to collect wind speed; a wind speed increase processing unit configured to If the wind speed change threshold is set, the electromagnetic torque of the wind turbine is kept at a fixed electromagnetic torque value, and the target pitch angle value of the wind turbine is increased, and the blade opening control is performed with the increased target pitch angle value; the wind speed decreases The processing unit is configured to reduce the electromagnetic torque and pitch angle of the wind generator, and calculate the cut-out electromagnetic torque value according to the real-time rotational speed of the wind generator if it is detected that the degree of wind speed decrease is greater than the second preset wind speed change threshold , if the difference between the real-time electromagnetic torque value of the wind turbine and the cut-out electromagnetic torque value is less than the preset torque threshold, the speed is controlled according to the preset speed-pitch angle relationship and the preset speed-electromagnetic torque relationship.

With reference to the second aspect, in some embodiments, the fixed electromagnetic torque value is the real-time electromagnetic torque value at the moment when the wind speed is determined to increase more than the first preset wind speed change threshold.

With reference to the second aspect, in some embodiments, the wind speed increase processing unit is further configured to:

In the process of propeller opening control with the increased target pitch angle value, the corresponding pitch angle value is calculated according to the real-time rotational speed of the wind turbine; if the corresponding pitch angle value is greater than the increased target pitch angle value, Then continue to increase the increased target pitch angle value.

With reference to the second aspect, in some embodiments, the wind speed reduction processing unit is specifically configured to reduce the electromagnetic torque and pitch angle.

With reference to the second aspect, in some embodiments, the wind speed reduction processing unit is specifically configured to, if the difference between the real-time electromagnetic torque value of the wind generator and the cut-out electromagnetic torque value is less than a preset threshold, according to the preset speed-propeller The distance angle PID relationship is used for speed control.

The wind speed control method and device provided by the embodiments of the present invention judge the wind condition by judging the increase degree of wind speed and the first preset wind speed change threshold, and by judging the wind speed decrease degree and the second preset wind speed change threshold Whether a mutation occurs. When the wind speed increase is greater than the first preset wind speed change threshold, it indicates that the wind speed has suddenly increased significantly. At this time, the electromagnetic torque of the wind turbine is kept at a fixed electromagnetic torque value, and the target pitch angle value is increased to achieve the increased The target pitch angle value is used for propeller opening control, and the increased target pitch angle value is more suitable for the pitch adjustment process at the next moment, that is to say, the increased target pitch angle value can make up for the loss in the pitch adjustment process. The error caused by hysteresis makes the speed of the wind turbine tend to be stable. When the degree of wind speed decrease is greater than the second preset wind speed change threshold, reduce the electromagnetic torque and pitch angle of the wind generator, and adjust the electromagnetic torque and pitch angle of the wind generator in time when the wind speed suddenly decreases to stabilize wind power generation machine speed. When the difference between the real-time electromagnetic torque of the wind turbine and the cut-out electromagnetic torque is less than the preset torque threshold, the preset speed-pitch angle relationship and the preset speed-electromagnetic torque relationship can be used for speed control, that is to say , after the wind condition returns to normal, the wind turbine also resumes normal speed control. Therefore, when the wind condition changes suddenly, the overspeed shutdown of the wind turbine caused by the sudden change of the wind condition can be avoided, thereby avoiding possible damage to the wind turbine.

Description of drawings

The present invention can be better understood from the following description of specific embodiments of the present invention in conjunction with the accompanying drawings, wherein the same or similar reference numerals represent the same or similar features.

1 is a flow chart of a method for controlling the speed of a wind power generator according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of a wind speed change curve, a pitch angle change curve, an electromagnetic torque change curve and a rotational speed change curve according to an embodiment of the present invention;

Fig. 3 is the schematic diagram of wind speed variation curve and rotating speed variation curve in the prior art;

4 is a flow chart of a method for controlling the speed of a wind power generator according to another embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a rotational speed control device of a wind power generator according to an embodiment of the present invention.

Detailed ways

Features and exemplary embodiments of various aspects of the invention will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by showing examples of the present invention. The present invention is by no means limited to any specific configurations and algorithms presented below, but covers any modification, substitution and improvement of elements, components and algorithms without departing from the spirit of the invention. In the drawings and the following description, well-known structures and techniques have not been shown in order to avoid unnecessarily obscuring the present invention.

When the wind condition of the wind turbine changes suddenly, for example, the wind speed suddenly increases significantly, the speed of the wind turbine will also increase due to the increase in wind speed, and it may drop sharply after the wind speed suddenly increases significantly , as the wind speed decreases, the speed of the wind turbine will also decrease. However, in the process of wind power generation, it is required that the rotation speed of the wind generator changes smoothly and stably. In order to ensure the stability of the rotation speed of the wind generator, the embodiments of the present invention propose the following solutions.

FIG. 1 is a flow chart of a method for controlling the speed of a wind power generator according to an embodiment of the present invention. The method for controlling the speed of a wind power generator as shown in FIG. 1 includes steps 101 to 104 .

In step 101, wind speed is collected.

Wherein, the wind speed may be collected periodically, and the shorter the wind speed collection period, the more accurate the result of judging whether a sudden change occurs in the wind condition. For example, in an example, the period for collecting wind speed may be 200 milliseconds.

In step 102, if the wind speed becomes greater than the first preset wind speed change threshold, the electromagnetic torque of the wind generator is maintained at a fixed electromagnetic torque value, and the target pitch angle value of the wind generator is increased to increase The final target pitch angle value is used for propeller opening control.

Wherein, the wind speed increase degree may be a difference between the wind speed increase and the wind speed increase, or may be the wind speed increase rate. The first preset wind speed change threshold is used to represent the cut-off point for judging whether the wind condition suddenly rises sharply. The first preset wind speed change threshold can be set according to factors such as the cycle of collecting wind speed and the sudden change of wind condition in the industry. When the degree of increase of the wind speed is greater than the first preset wind speed change threshold, it indicates that the wind speed increases suddenly and greatly. In order to avoid the problem of sudden increase in the speed of the wind turbine caused by a sudden and large increase in wind speed, the electromagnetic torque of the wind turbine is kept at a fixed electromagnetic torque value, and the target pitch angle value of the wind turbine is increased to increase the The target pitch angle value is used for propeller opening control.

The fixed electromagnetic torque value is the rotational speed when it is determined that the degree of wind speed increase is greater than the first preset wind speed change threshold, and the wind power generator will turn The electromagnetic torque value remains at a fixed electromagnetic torque value. The preset speed-electromagnetic torque relationship of the wind generator may be one of the characteristic relationships of the wind generator itself, specifically, it may be a speed-electromagnetic torque curve provided by the wind generator manufacturer. The target pitch angle value is the set pitch angle value expected to be achieved by the wind turbine. The target pitch angle value will be 5°-7° greater than the original target pitch angle value of the wind turbine when the wind speed becomes greater than the first preset wind speed change threshold, wherein the original target pitch angle value is It is obtained according to the current rotational speed of the wind turbine and a preset rotational speed-pitch angle relationship, and the preset rotational speed-pitch angle relationship may specifically be a rotational speed-pitch angle PID calculation. For example, when the wind speed increase is greater than the first preset wind speed change threshold, the original target pitch angle value of the wind turbine is 2°, and the increased target pitch angle value can be set to 7°-9° °. A sudden increase in wind speed will increase the speed of the wind turbine, and increasing the pitch angle of the blades can reduce the speed of the wind generator, thereby ensuring a stable speed of the wind generator. Since the wind speed is in the rising stage, when the wind speed is in the initial stage of the rising stage, the speed difference between the two moments of the wind turbine is small, and the pitch speed obtained by using the existing preset speed-pitch angle PID calculation is also relatively small. is small, so that the obtained original target pitch angle value is also relatively small, that is to say, the pitch angle value obtained by using the preset speed-pitch angle PID calculation is also relatively small when the wind condition changes suddenly, resulting in a with hysteresis. The embodiment of the present invention utilizes the increased target pitch angle value to perform propeller opening control, so that the pitch adjustment process of the wind power generator is more timely.

According to the principle of energy conservation, wind energy is equal to the sum of the energy generated by the rotation of the wind generator and the energy generated by the electromagnetic torque of the wind generator. The target pitch angle value is set, and the propeller opening control is performed with an increased target pitch angle value, which can avoid the sudden increase in the speed of the wind turbine caused by a sudden and large increase in wind speed.

In step 103, if it is detected that the degree of wind speed reduction is greater than the second preset wind speed change threshold, then reduce the electromagnetic torque and pitch angle of the wind generator, and calculate the cut-out electromagnetic torque value according to the real-time speed of the wind generator, If the difference between the real-time electromagnetic torque value of the wind turbine and the cut-out electromagnetic torque value is less than the preset torque threshold, the speed is controlled according to the preset speed-pitch angle relationship and the preset speed-electromagnetic torque relationship.

Wherein, the wind speed reduction degree may be a difference between the wind speed reduction and before the wind speed reduction, or may be the wind speed reduction rate. The second preset wind speed change threshold is used to represent the cut-off point for judging whether the wind condition suddenly drops significantly. The second preset wind speed change threshold can be set according to factors such as the cycle of collecting wind speed and the sudden change standard of wind condition in the industry.

When the wind speed decreases sharply and suddenly, the electromagnetic torque and the pitch angle of the wind generator are reduced to avoid the problem of a sudden drop in the speed of the wind generator caused by the sudden sharp decrease of the wind speed. The cut-out electromagnetic torque value is the electromagnetic torque value corresponding to the real-time speed of the wind turbine in the preset speed-electromagnetic torque relationship, when the difference between the real-time electromagnetic torque value of the wind turbine and the cut-out electromagnetic torque value is less than the preset torque When the threshold is reached, the rotational speed control process of this scheme can be exited, and the rotational speed can be controlled according to the preset rotational speed-pitch angle relationship and the preset rotational speed-electromagnetic torque relationship. That is, the cut-out electromagnetic torque value is obtained by using the real-time rotational speed and the characteristic relationship of the wind turbine itself. The wind turbine resumes the speed control when the wind condition changes gently (ie, normal wind condition). It should be noted that the predetermined torque threshold can be set according to a specific working scenario, and the setting method is not limited here. For example, if the predetermined torque threshold is 100Nm/40ms, and the difference between the real-time electromagnetic torque value of the wind turbine and the cut-out electromagnetic torque is less than 100Nm/40ms, then the control method of the wind turbine in the embodiment of the present invention can be ended, and the ordinary wind turbine can be used. The control method of the wind generator under the condition controls the electromagnetic torque and the pitch angle of the wind generator, thereby controlling the wind speed of the wind generator.

The speed control method of the wind power generator provided by the embodiment of the present invention judges whether the wind condition occurs by judging the increase degree of the wind speed and the first preset wind speed change threshold, and by judging the wind speed decrease degree and the second preset wind speed change threshold mutation. When the wind speed increase is greater than the first preset wind speed change threshold, it indicates that the wind speed has suddenly increased significantly. At this time, the electromagnetic torque of the wind turbine is kept at a fixed electromagnetic torque value, and the target pitch angle value is increased to achieve the increased The target pitch angle value is used for propeller opening control, and the increased target pitch angle value is more suitable for the pitch adjustment process at the next moment, that is to say, the increased target pitch angle value can make up for the loss in the pitch adjustment process. The error caused by hysteresis makes the speed of the wind turbine tend to be stable. When the degree of wind speed decrease is greater than the second preset wind speed change threshold, reduce the electromagnetic torque and pitch angle of the wind generator, and adjust the electromagnetic torque and pitch angle of the wind generator in time when the wind speed suddenly decreases to stabilize wind power generation machine speed. When the difference between the real-time electromagnetic torque of the wind turbine and the cut-out electromagnetic torque is less than the preset torque threshold, the preset speed-pitch angle relationship and the preset speed-electromagnetic torque relationship can be used for speed control, that is to say , after the wind condition returns to normal, the wind turbine also resumes normal speed control. Therefore, when the wind condition changes suddenly, the overspeed shutdown of the wind turbine caused by the sudden change of the wind condition can be avoided, thereby avoiding possible damage to the wind turbine. Moreover, the embodiment of the present invention can make the change of the rotational speed of the wind-driven generator more gentle, reduce the absolute value of the acceleration of the rotational speed, thereby reducing the impact force on the wind-driven generator caused by the acceleration, and reducing the impact on the wind force. Damage to generators.

It should be noted that the fixed electromagnetic torque in the above embodiment is the real-time electromagnetic torque value at the moment when the wind speed is determined to increase more than the first preset wind speed change threshold. When it is detected that the degree of wind speed decrease is greater than the second preset wind speed change threshold, the electromagnetic torque and the pitch angle of the wind generator are reduced, specifically, the electromagnetic torque and the pitch angle of the wind generator can be respectively reduced at a preset speed, Wherein, the value of the preset speed of electromagnetic torque reduction and the value of the preset speed of pitch angle reduction can be the same or different, and the value of the preset speed of electromagnetic torque reduction and the value of the preset speed of electromagnetic torque reduction can be set according to specific working scenarios. The value of the preset speed at which the pitch angle decreases.

For example, FIG. 2 is a schematic diagram of a wind speed change curve, an electromagnetic torque change curve, a pitch angle change curve and a rotational speed change curve in an embodiment of the present invention. In Fig. 2, the abscissa represents the time, the ordinate of the wind speed change curve represents the wind speed, the ordinate of the electromagnetic torque change curve represents the electromagnetic torque value, the ordinate of the pitch angle change curve represents the pitch angle value, and the ordinate of the speed change curve Coordinates represent rotational speed values. As shown in Figure 2, the degree of increase in wind speed at time t2 is greater than the first wind speed change threshold, from time t2 to time t3, the electromagnetic torque of the wind turbine maintains the electromagnetic torque value at time t2, and the propeller opening control is performed from time t2, At time t3, the propeller opening control process is completed, and the pitch angle of the wind turbine is adjusted to the increased target pitch angle value. At time t3, the wind speed begins to decrease, and the decrease degree of wind speed at time t3 is greater than the second preset wind speed change threshold. From time t3, the electromagnetic torque and pitch angle of the wind turbine are reduced. At time t4, the wind generator The real-time electromagnetic torque value is equal to the cut-out electromagnetic torque. From time t4, the pitch angle of the wind turbine is obtained by using the preset speed-pitch angle relationship, and the wind turbine pitch angle is obtained by using the preset speed-electromagnetic torque relationship. Electromagnetic torque, so as to jointly control the speed of the wind turbine from the two aspects of the pitch angle and the electromagnetic torque. Wherein, specifically, the preset speed-pitch angle relationship is used to obtain the pitch angle of the wind turbine, which can be performed according to the preset speed-pitch angle PID relationship (that is, the speed-pitch angle PID calculation). The pitch angle control, so as to control the speed. It can be seen from FIG. 2 that the speed change curve of the wind power generator obtained by using the method for controlling the wind power generator when the wind condition suddenly changes in the embodiment of the present invention changes smoothly and has little fluctuation. Fig. 3 is a schematic diagram of a wind speed change curve and a rotational speed change curve when the wind condition suddenly changes in the prior art. It can be seen from FIG. 3 that under the same wind speed scenario as in FIG. 2 , the speed change curve of the wind power generator in the prior art changes greatly and fluctuates violently. From the comparison of Fig. 2 and Fig. 3, it can be seen that the control method of the wind power generator according to the embodiment of the present invention can effectively stabilize the speed of the wind power generator, so as to prevent the wind power generator from shutting down due to overspeed.

Fig. 4 is a flow chart of a method for controlling the rotational speed of a wind power generator according to another embodiment of the present invention. Step 101 and step 103 in Fig. 4 are basically the same as step 101 and step 103 in Fig. 1, the difference is that Fig. 1 Step 102 shown in can be specifically detailed as step 1021-step 1024.

In step 1021, if the wind speed becomes greater than the first preset wind speed change threshold, then keep the electromagnetic torque of the wind generator at a fixed value, and increase the target pitch angle of the wind generator.

In step 1022, during the process of blade opening control with the increased target pitch angle value, the corresponding pitch angle value is calculated according to the real-time rotational speed of the wind turbine.

Wherein, during the propeller opening control process with the increased target pitch angle value, the corresponding pitch angle value is calculated according to the real-time rotational speed of the wind turbine using the preset rotational speed-pitch angle value relationship.

In step 1023, if the corresponding pitch angle value is greater than the increased target pitch angle value, continue to increase the increased target pitch angle value, and proceed with the increased target pitch angle value again. paddle control.

Wherein, if the corresponding pitch angle value calculated in step 1022 is greater than the increased target pitch angle value, it indicates that the increase of the target pitch angle value is not enough, according to the increased pitch angle value in step 1021 Adjusting the pitch angle of the wind turbine by the value may make the speed of the wind turbine slightly higher. Therefore, when it is determined that the corresponding pitch angle value calculated according to the real-time speed of the wind turbine and the preset speed-pitch angle relationship is greater than the increased target pitch angle value during the blade control process, continue to increase With the increased target pitch angle value, the target pitch angle value of the wind turbine can finally be adjusted to a more appropriate pitch angle value, further ensuring the stable speed of the wind turbine. Moreover, the target pitch angle value is adjusted during the propeller opening control process, so that in the case of a sudden and large increase in wind speed, the speed of the wind turbine can be stabilized once the propeller opening control is performed, avoiding the wind speed in the case of a sudden and large increase in wind speed. Perform multiple propeller opening controls.

Fig. 5 is a schematic structural diagram of a speed control device 200 for a wind power generator provided by an embodiment of the present invention. The speed control device 200 for a wind power generator as shown in Fig. 5 includes a wind speed acquisition unit 201 and a wind speed increase processing unit 202 and the wind speed reduction processing unit 203.

The wind speed collecting unit 201 is configured to collect wind speed.

The wind speed increase processing unit 202 is configured to keep the electromagnetic torque of the wind generator at a fixed electromagnetic torque value and increase the target blade of the wind generator if the wind speed increase is greater than the first preset wind speed change threshold. pitch angle value, the propeller opening control is performed with the increased target pitch angle value.

The wind speed reduction processing unit 203 is configured to reduce the electromagnetic torque and the pitch angle of the wind generator if it is detected that the degree of wind speed reduction is greater than the second preset wind speed change threshold, and according to the real-time The speed calculation cuts out the electromagnetic torque value. If the difference between the real-time electromagnetic torque value of the wind generator and the cut-out electromagnetic torque value is less than the preset torque threshold, according to the preset speed-pitch angle relationship and the preset Speed control based on the speed-electromagnetic torque relationship.

The speed control device 200 of the wind power generator provided by the embodiment of the present invention collects the wind speed through the wind speed acquisition unit 201, and utilizes the wind speed increase processing unit 202 and the wind speed decrease processing unit 203 respectively when the wind speed increase degree is greater than the first preset wind speed change threshold When the time and wind speed decrease are greater than the second preset wind speed change threshold, the pitch angle and the electromagnetic torque of the wind generator are adjusted. Specifically, by judging the wind speed increase degree and the first preset wind speed change threshold, as well as the wind speed decrease degree and the second preset wind speed change threshold, it is judged whether the wind condition has a sudden change. When the wind speed increase is greater than the first preset wind speed change threshold, it indicates that the wind speed has suddenly increased significantly. At this time, the electromagnetic torque of the wind turbine is kept at a fixed electromagnetic torque value, and the target pitch angle value is increased to achieve the increased The target pitch angle value is used for propeller opening control, and the increased target pitch angle value is more suitable for the pitch adjustment process at the next moment, that is to say, the increased target pitch angle value can make up for the loss in the pitch adjustment process. The error caused by hysteresis makes the speed of the wind turbine tend to be stable. When the degree of wind speed decrease is greater than the second preset wind speed change threshold, reduce the electromagnetic torque and pitch angle of the wind generator, and adjust the electromagnetic torque and pitch angle of the wind generator in time when the wind speed suddenly decreases to stabilize wind power generation machine speed. When the difference between the real-time electromagnetic torque of the wind turbine and the cut-out electromagnetic torque is less than the preset torque threshold, the preset speed-pitch angle relationship and the preset speed-electromagnetic torque relationship can be used for speed control, that is to say , after the wind condition returns to normal, the wind turbine also resumes normal speed control. Therefore, when the wind condition changes suddenly, the overspeed shutdown of the wind turbine caused by the sudden change of the wind condition can be avoided, thereby avoiding possible damage to the wind turbine. Moreover, the embodiment of the present invention can make the change of the rotational speed of the wind-driven generator more gentle, reduce the absolute value of the acceleration of the rotational speed, thereby reducing the impact force on the wind-driven generator caused by the acceleration, and reducing the impact on the wind force. Damage to generators.

It should be noted that the fixed electromagnetic torque value in the above embodiment is the real-time electromagnetic torque value at the moment when the wind speed is determined to increase more than the first preset wind speed change threshold.

The wind speed increase processing unit 202 in the above-mentioned embodiment may also be configured to calculate the corresponding pitch angle value according to the real-time rotational speed of the wind turbine during the blade opening control process with the increased target pitch angle value; If the pitch angle value is greater than the increased target pitch angle value, continue to increase the increased target pitch angle value.

The wind speed reduction processing unit 203 in the above embodiment may be specifically configured to reduce the electromagnetic torque and the pitch angle of the wind generator at a preset speed if it is detected that the degree of wind speed reduction is greater than the second preset wind speed change threshold.

The wind speed reduction processing unit 203 in the above embodiment can be specifically configured to, if the difference between the real-time electromagnetic torque value of the wind turbine and the cut-out electromagnetic torque value is less than a preset threshold, according to the preset speed-pitch angle PID relationship Perform speed control.

The functional units shown in the above structural diagrams may be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it may be, for example, an electronic circuit, an application specific integrated circuit (ASIC), suitable firmware, a plug-in, a function card, or the like. When implemented in software, the elements of the invention are the programs or code segments employed to perform the required tasks. Programs or code segments can be stored in machine-readable media, or transmitted over transmission media or communication links by data signals carried in carrier waves. "Machine-readable medium" may include any medium that can store or transmit information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, and the like. Code segments may be downloaded via a computer network such as the Internet, an Intranet, or the like.

The present invention is not limited to the specific steps and structures described above and shown in the drawings. Also, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here. For example, in the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention .

Claims (10)

1. A speed control method of a wind-driven generator, characterized in that, comprising: collection wind speed; If the wind speed becomes greater than the first preset wind speed change threshold, the electromagnetic torque of the wind generator is maintained at a fixed electromagnetic torque value, and the target pitch angle value of the wind generator is increased, with the increased The target pitch angle value is used for propeller opening control; If it is detected that the degree of wind speed reduction is greater than the second preset wind speed change threshold, then reduce the electromagnetic torque and pitch angle of the wind generator, and calculate the cut-out electromagnetic torque value according to the real-time speed of the wind generator, if When the difference between the real-time electromagnetic torque value of the wind generator and the cut-out electromagnetic torque value is less than the preset torque threshold, the speed is controlled according to the preset speed-pitch angle relationship and the preset speed-electromagnetic torque relationship . 2. The speed control method of a wind-driven generator according to claim 1, wherein the fixed electromagnetic torque value is a real-time electromagnetic torque value at a time when the wind speed is determined to be greater than a first preset wind speed change threshold . 3. The rotational speed control method of the wind-driven generator according to claim 2, is characterized in that, in the process of carrying out propeller opening control with the target pitch angle value after the increase: calculating a corresponding pitch angle value according to the real-time rotational speed of the wind generator; If the corresponding pitch angle value is greater than the increased target pitch angle value, continue to increase the increased target pitch angle value. 4. The method for controlling the rotational speed of a wind power generator according to any one of claims 1-3, wherein if it is detected that the degree of wind speed decrease is greater than a second preset wind speed change threshold, then the wind speed is reduced. The steps of electromagnetic torque and pitch angle of wind turbine include: If it is detected that the degree of decrease in wind speed is greater than the second preset wind speed change threshold, the electromagnetic torque and the pitch angle of the wind generator are respectively reduced at a preset speed. 5. The speed control method of a wind-driven generator according to claim 1, wherein, when the difference between the real-time electromagnetic torque value of the wind-driven generator and the cut-out electromagnetic torque value is less than a preset torque threshold, according to the preset The steps for speed control based on the speed-pitch angle relationship include: If the difference between the real-time electromagnetic torque value of the wind power generator and the cut-out electromagnetic torque value is less than a preset threshold, the speed control is performed according to a preset speed-pitch angle PID relationship. 6. A speed control device for a wind-driven generator when the wind condition changes abruptly, characterized in that it comprises: a wind speed collection unit configured to collect wind speed; The wind speed increase processing unit is configured to keep the electromagnetic torque of the wind generator at a fixed electromagnetic torque value and increase the target pitch of the wind generator if the wind speed becomes larger than the first preset wind speed change threshold Angle value, the propeller opening control is performed with the increased target pitch angle value; The wind speed reduction processing unit is configured to reduce the electromagnetic torque and pitch angle of the wind generator if it detects that the wind speed has decreased to a degree greater than the second preset wind speed change threshold, and according to the real-time rotation speed of the wind generator Calculate the cut-out electromagnetic torque value, if the difference between the real-time electromagnetic torque value of the wind generator and the cut-out electromagnetic torque value is less than the preset torque threshold value, according to the preset speed-pitch angle relationship and the preset The speed-electromagnetic torque relationship is used for speed control. 7. The rotational speed control device of a wind power generator according to claim 6, wherein the fixed electromagnetic torque value is the real-time electromagnetic torque value at the moment when the wind speed is determined to be larger than the first preset wind speed change threshold . 8. The rotational speed control device of a wind power generator according to claim 7, wherein the wind speed increase processing unit is further configured to: In the process of performing propeller opening control with the increased target pitch angle value, the corresponding pitch angle value is calculated according to the real-time rotational speed of the wind turbine; if the corresponding pitch angle value is greater than the increased If the target pitch angle value is increased, continue to increase the increased target pitch angle value. 9. The rotational speed control device of a wind power generator according to any one of claims 6-8, wherein the wind speed reduction processing unit is specifically configured to detect that the degree of wind speed reduction is greater than the second preset wind speed If the threshold value is changed, the electromagnetic torque and the pitch angle of the wind generator are respectively reduced at a preset speed. 10. The rotational speed control device of a wind-driven generator according to claim 6, wherein the wind speed reduction processing unit is specifically configured such that if the real-time electromagnetic torque value of the wind-driven generator is equal to the cut-out electromagnetic torque value When the difference of is less than the preset threshold, the speed control is performed according to the preset speed-pitch angle PID relationship.