CN117823342A

CN117823342A - Variable pitch control method of wind generating set, controller and wind generating set

Info

Publication number: CN117823342A
Application number: CN202211184676.1A
Authority: CN
Inventors: 霍钧; 胡炜; 马磊; 卢勇
Original assignee: Beijing Etechwin Electric Co Ltd
Current assignee: Beijing Etechwin Electric Co Ltd
Priority date: 2022-09-27
Filing date: 2022-09-27
Publication date: 2024-04-05

Abstract

A variable pitch control method of a wind generating set, a controller and the wind generating set are disclosed. The pitch control method comprises the following steps: determining a representative difference of a given pitch speed and an actual pitch speed over a predetermined period of time in response to a measured temperature of the pitch motor abrupt during a pitch operation; determining a theoretical temperature of the pitch motor at the end time of the preset time period according to a preset corresponding relation between the pitch speed difference value and the temperature change rate based on the representative difference value; and controlling the pitch system to enter a redundant operation mode in response to the theoretical temperature being less than or equal to a preset temperature threshold. According to the pitch control method, the controller and the wind generating set, the temperature of the pitch motor can be effectively predicted under the condition that the temperature sensor of the pitch motor is abnormal and the current value of the pitch motor cannot be obtained, so that redundant operation of a pitch system is realized, and the operation safety of the wind generating set is not affected.

Description

Variable pitch control method of wind generating set, controller and wind generating set

Technical Field

The present disclosure relates generally to the field of wind power generation technology, and more particularly, to a pitch control method of a wind turbine generator set, a controller, and a wind turbine generator set.

Background

The variable pitch system of the wind generating set plays an important role in tracking the maximum power of the wind generating set and ensuring the safe shutdown of the wind generating set. Specifically, one main function of the pitch system is to act as a main braking system of the wind generating set, and the pitch system ensures safe and stable operation of the wind generating set through multiple detection and control means and multiple redundancy designs.

Typically, the ideal operating temperature range for a pitch motor is 20-70 ℃. The variable pitch motor is a main power unit for adjusting the pitch of the variable pitch system, and if the temperature of the variable pitch motor is too high, the variable pitch motor is easy to burn out, so that blades are clamped completely and cannot feathering to a safe position. Therefore, monitoring the temperature of the pitch motor has an important impact on the safety of the wind power generator set.

In general, a pitch system (e.g., a pitch controller) monitors the temperature of a pitch motor in real time. When the temperature of the pitch motor exceeds a fault threshold (e.g., 140 ℃), a wind turbine generator set fault shutdown is triggered. However, in actual operation, the situation that the Hatin head of the pitch motor is broken and falls due to breaking and falling of the pitch bearing bolts happens many times, and after the Hatin head is broken, a brake power supply circuit, a temperature sensor and the like of the pitch motor in the pitch system are broken, so that the pitch controller cannot acquire a real temperature value of the pitch motor and cannot detect that the pitch motor is blocked, and therefore the pitch controller can always control the pitch motor to operate, and the temperature of the pitch motor is continuously increased.

When the temperature of the pitch motor is higher than a protection threshold (e.g., 150 ℃), the pitch motor protection control logic can be triggered to temporarily stop the operation of the pitch motor, and when the temperature is waiting to fall below a fault threshold, the pitch motor is started again to execute the pitch-withdrawing operation. The reason for this is that the coils of the pitch motor are wound by enameled wires, the aging temperature of the enameled wires is generally slightly higher than the protection threshold, if the temperature of the pitch motor is too high, the enameled wires can be aged and embrittled, so that the pitch motor is caused to be short-circuited, and the pitch motor is burnt.

After the pitch motor is burnt out, the cost of the wind turbine generator set will be increased in order to replace the pitch motor. On the other hand, because the variable pitch motor is heavy, the replacement is time-consuming and labor-consuming, and because the variable pitch motor is long in time-consuming, the downtime of the wind generating set is prolonged, and the power generation loss is increased. More seriously, when the pitch motor is burnt out due to overhigh temperature, the ignition inside the hub can be triggered, and more serious consequences and losses are caused.

Disclosure of Invention

Therefore, the embodiment of the disclosure provides a pitch control method of a wind generating set, a controller and the wind generating set, which can effectively predict the temperature of a pitch motor under the condition that a temperature sensor of the pitch motor is abnormal and the current value of the pitch motor cannot be obtained, thereby realizing redundant operation of a pitch system and not affecting the operation safety of the wind generating set.

In one general aspect, there is provided a pitch control method of a wind turbine, the pitch control method comprising: determining a representative difference of a given pitch speed and an actual pitch speed over a predetermined period of time in response to a measured temperature of the pitch motor abrupt during a pitch operation; determining a theoretical temperature of the pitch motor at the end time of the preset time period according to a preset corresponding relation between the pitch speed difference value and the temperature change rate based on the representative difference value; and controlling the pitch system to enter a redundant operation mode in response to the theoretical temperature being less than or equal to a preset temperature threshold.

Optionally, determining that the measured temperature of the pitch motor is suddenly changed in response to the rate of change of the temperature of the pitch motor at the first and second moments being greater than a first threshold and/or the difference of the temperatures of the pitch motor at the first and second moments being greater than a second threshold.

Optionally, the pitch control method further includes: and triggering the wind generating set to stop in a fault mode in response to the theoretical temperature being greater than a preset temperature threshold.

Optionally, the step of determining a representative difference of the given pitch speed and the actual pitch speed over a predetermined period of time comprises: determining an average value of a given pitch speed over the predetermined period of time, and determining an average value of an actual pitch speed over the predetermined period of time; the difference between the average value of the given pitch speed and the average value of the actual pitch speed is taken as the representative difference.

Optionally, the step of determining a representative difference of the given pitch speed and the actual pitch speed over a predetermined period of time comprises: determining a difference between a given pitch speed and an actual pitch speed at each moment in the predetermined time period; the average of the differences between a given pitch speed and the actual pitch speed at each instant is taken as the representative difference.

Optionally, the predetermined period of time starts from a time preceding a time when the measured temperature of the pitch motor is suddenly changed.

Optionally, the correspondence of the pitch speed difference to the temperature change rate is determined by: determining a change rate of a measured temperature of the pitch motor for each time interval within a preset historical time period, and determining an average value of differences between an actual pitch speed and a given pitch speed for each time interval; and performing curve fitting based on the change rate of the measured temperature of the pitch motor at each time interval and the average value of the difference value between the actual pitch speed and the given pitch speed at each time interval to obtain the corresponding relation between the pitch speed difference value and the temperature change rate.

Optionally, the step of determining the rate of change of the measured temperature of the pitch motor for each time interval within the preset historical period of time comprises: determining a correction value of a measured temperature at each time in any one time interval, wherein, for any one time, if the measured temperature at any one time is smaller than the measured temperature at the previous time of any one time, the measured temperature at the previous time of any one time is taken as the correction value of the measured temperature at any one time, and if the measured temperature at any one time is greater than or equal to the measured temperature at the previous time of any one time, the measured temperature at any one time is taken as the correction value of the measured temperature at any one time; and determining the change rate of the measured temperature of any one time interval based on the corrected value of the measured temperature at the ending time of the any one time interval and the measured temperature at the initial time of the preset historical time interval.

Optionally, in the first N time intervals in the preset historical time period, the pitch motor is in a normal running state, and in the remaining M time intervals in the preset historical time period, the pitch motor is in a locked-rotor state, wherein N and M are integers greater than 1, and N is less than M.

Optionally, the duration of the preset historical time period is in the order of minutes, and the duration of each time interval in the preset historical time period is in the order of seconds.

In another general aspect, there is provided a computer-readable storage medium storing a computer program which, when executed by a processor, implements a pitch control method as described above.

In another general aspect, there is provided a controller including: a processor; and a memory storing a computer program which, when executed by the processor, implements a pitch control method as described above.

In another general aspect, there is provided a wind power plant, characterized in that the wind power plant comprises a controller as described above.

According to the pitch control method of the wind generating set, the controller and the wind generating set, under the condition that the temperature sensor of the pitch motor is abnormal and the current value of the pitch motor cannot be obtained, the temperature value of the pitch motor is accurately predicted only according to the given pitch speed and the actual pitch speed of the pitch system, so that redundant operation of the pitch system is realized on the premise that the operation safety of the wind generating set is ensured, and the loss of generated energy is reduced. Meanwhile, the temperature value of the variable-pitch motor can be accurately predicted under the condition that the temperature sensor of the variable-pitch motor is abnormal and the current value of the variable-pitch motor cannot be obtained, so that the variable-pitch motor can be effectively prevented from being burnt out due to overhigh temperature, and the component loss and the cost loss of the wind generating set are reduced.

Drawings

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

FIG. 1 is a diagram illustrating an example of a pitch system of a wind turbine;

FIG. 2 is a graph showing angle curves of three blades of a wind turbine and temperature curves of a corresponding pitch motor;

FIG. 3 is a graph illustrating a given pitch speed versus an actual pitch speed for a pitch system where anomalies occur;

FIG. 4 is a scatter plot showing the difference between a given pitch speed and an actual pitch speed of a pitch system and the temperature of a pitch motor according to an embodiment of the present disclosure;

FIG. 5 is a flow chart illustrating a method of pitch control of a wind turbine generator set according to an embodiment of the present disclosure;

FIG. 6 is a flow chart illustrating a method of determining a correspondence of a difference between a given pitch speed and an actual pitch speed (i.e., a pitch speed difference) to a temperature rate of change in accordance with an embodiment of the present disclosure;

FIG. 7 is a graph showing measured temperatures of a pitch motor and correction values thereof over a time interval;

FIG. 8 is a graph showing the correspondence of the pitch speed difference value obtained by curve fitting to the temperature change rate;

FIG. 9 is a block diagram illustrating a controller according to an embodiment of the present disclosure;

FIG. 10 is a control topology of a pitch system of a wind turbine according to an embodiment of the present disclosure;

fig. 11 is a diagram illustrating a comparative example of a measured temperature and a theoretical temperature of a pitch motor in a pitch control method according to an embodiment of the present disclosure.

Detailed Description

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

In the prior art, in order to avoid that the temperature sensor of the pitch motor is abnormal and the temperature of the pitch motor cannot be accurately detected, two temperature sensors are usually installed inside the pitch motor to detect the temperature of the pitch motor. However, the temperature sensor needs to be installed inside the pitch motor, and the motor is required to be disassembled for the original pitch motor which is used after being accessed, so that the temperature sensor is not easy to realize. On the other hand, even if two temperature sensors are installed, the two temperature sensors are one and the other, that is, the pitch controller only collects the measured value of one temperature sensor, when the temperature sensor is abnormal or damaged, the manual line change is needed to collect the measured value of the other temperature sensor, and in the process, the wind turbine generator set still possibly triggers the fault shutdown to influence the generated energy. Furthermore, the operating environment of the pitch system is relatively complex, and the output signal of the pitch drive belongs to a high frequency signal, which may cause electromagnetic interference to the temperature sensor, and even if a standby temperature sensor is used, electromagnetic interference will be received to cause a jump in the measured value.

Therefore, the present disclosure provides a pitch control method of a wind turbine generator system, which is capable of calculating a theoretical temperature value of a pitch motor as a temperature predicted value of the pitch motor according to a given pitch speed, an actual pitch speed, and a temperature change rate when the pitch motor is locked under the condition that a temperature sensor is disconnected, short-circuited, or a measured value jumps, so as to implement redundant operation (i.e., fault tolerant operation) of the pitch system based on the temperature predicted value.

In the following, the principles of the present disclosure are first described.

Fig. 1 is a diagram illustrating an example of a pitch system of a wind turbine.

Referring to fig. 1, the pitch system may include a pitch motor 101, a supercapacitor 102, a pitch controller 103, a pitch drive 104, an enable switch (limit switch) 105, a brake relay 106, an encoder 107, and a temperature sensor 108.

When pitch drive 104 is operating normally, enable switch (limit switch) 105 is in a closed state and pitch drive 104 is powered. When the pitch controller 103 receives a pitch speed command of the main controller of the wind generating set, or when the pitch controller 103 detects that the pitch system is faulty and feathering is performed autonomously, the pitch controller 103 sends a speed command and an enable signal to the pitch drive 104 through the signal transmission channel 109. After receiving the speed command and the enable signal, the pitch drive 104 controls the brake relay 106 to open the brake, and provides an output voltage through the power transmission channel 110 to drive the pitch motor 101 to rotate, thereby realizing the pitch function.

The encoder 107 may measure the blade angle value of the wind park and provide the measured blade angle value to the pitch drive 104 and/or the pitch controller 103. Pitch drive 104 and/or pitch controller 103 may calculate the rotational speed of pitch motor 101 based on the read encoder values. Pitch drive 104 compares the calculated rotational speed to the value of the speed command sent to pitch drive 104 by pitch controller 103. If the calculated rotational speed is less than the speed command value, pitch drive 104 may increase the output voltage to increase the rotational speed of pitch motor 101. If the calculated rotational speed is greater than the speed command value, pitch drive 104 decreases the output voltage to decrease the rotational speed of pitch motor 101. In this way, the rotational speed of the pitch motor 101 may eventually be brought to a value corresponding to a given speed command.

The temperature sensor 108 may measure the temperature of the pitch motor 101 and may provide the measured value to the pitch controller 103 via the pitch drive 104. Alternatively, the temperature sensor 108 may send the measured values directly to the pitch controller 103 without passing through the pitch drive 104.

Pitch controller 103 may control the overall operation of the pitch system and may communicate with a main controller of the wind turbine, receive control commands sent by the main controller and/or send status information of the pitch system to the main controller.

During normal operation of the pitch system, the temperature rise of the pitch motor 101 is not significant. However, when the brake valve of the pitch motor wears, the brake valve fails to lock (cannot be released), the encoder increment signal is abnormal, the driver parameter is wrong, or the pitch motor is mechanically stuck, the actual speed of the pitch motor 101 cannot reach the given speed, and the current of the pitch motor 101 is increased by the closed-loop control of the pitch driver 104 to increase the output speed of the pitch motor 101, so that the actual speed of the pitch motor 101 follows the given speed. Therefore, when a deviation occurs between a given speed and an actual speed, the current of the pitch motor 101 increases sharply, and causes the temperature of the pitch motor 101 to increase sharply. In this case, if the measured value of the temperature sensor 108 jumps or is abnormal, in order to ensure the safety of the pitch system, only the wind turbine generator set can be triggered to stop, and temporary stop protection is performed on the pitch motor 101, otherwise, the pitch motor 101 may be burned out, resulting in a large economic loss.

Fig. 2 is a diagram showing the angle curves of three blades of a wind power plant and the temperature curves of the corresponding pitch motors.

Referring to fig. 2, curves 201, 202, and 203 represent angle curves of three blades, respectively, and curves 211, 212, and 213 represent temperature curves of a pitch motor corresponding to the three blades, respectively. The abscissa represents the time value and the ordinate schematically represents the angle value and the temperature value. As can be seen from fig. 2, at time 0, the angle curve 203 of the first blade changes slowly due to an abnormality in the pitch system of the first blade (e.g., brake valve wear), i.e., the angle value of the first blade changes slowly, while the pitch systems of the other blades operate normally, so the angle values of the angle curves 201 and 202 of the other blades change normally, and the two substantially coincide. Meanwhile, the temperature profile 213 of the pitch motor corresponding to the first blade increases rapidly, that is, the temperature of the pitch motor corresponding to the first blade increases sharply, while the temperature profiles 211 and 212 of the pitch motors corresponding to the other blades do not change much.

FIG. 3 is a graph illustrating a given pitch speed versus an actual pitch speed for a pitch system where anomalies occur.

Referring to fig. 3, curve 301 represents a given pitch speed and curve 302 represents an actual pitch speed. The abscissa represents the time value and the ordinate represents the speed value. As shown in fig. 3, after an anomaly in the pitch system (e.g., brake valve wear) occurs, the deviation between curve 301 and curve 302 becomes greater. Accordingly, the slope of the temperature curve 213 in fig. 2 is also increasingly larger. Therefore, a certain corresponding relation exists between the difference value of the given pitch speed and the actual pitch speed and the temperature change rate of the pitch motor, and the feasibility of the method is reflected.

Fig. 4 is a scatter plot showing the difference between a given pitch speed and an actual pitch speed of a pitch system and the temperature of a pitch motor according to an embodiment of the present disclosure.

Referring to fig. 4, curve 401 represents the difference between a given pitch speed and an actual pitch speed, and curve 402 represents the temperature profile of the pitch motor. The abscissa represents the time value and the ordinate schematically represents the angle value and the temperature value. As shown in fig. 4, as the difference between a given pitch speed and an actual pitch speed becomes larger, the slope of the temperature curve 402 becomes larger, and the two show a certain correspondence. Here, it should be noted that, since the temperature change rate or the change amount of the pitch motor is not very large in a short period of time, for example, in several sampling periods (for example, but not limited to, 20 ms) of the pitch controller, it is necessary to acquire a temperature value for a relatively long period of time when determining the correspondence of the speed difference value and the temperature change rate.

Fig. 5 is a flowchart illustrating a pitch control method of a wind turbine generator set according to an embodiment of the present disclosure.

Referring to fig. 5, in step S501, in response to an abrupt change in measured temperature of a pitch motor during a pitch operation, a representative difference of a given pitch speed and an actual pitch speed over a predetermined period of time is determined. Here, the predetermined period of time may be 4 to 10 seconds long, but the present disclosure is not limited thereto. For example, the duration of the predetermined period of time may be set to 2 seconds.

According to embodiments of the present disclosure, when a rate of change of a temperature of a pitch motor at two times (i.e., sampling times of a pitch controller) before and after (i.e., a ratio of a difference between the temperatures of the pitch motor at the two times before and after to a time period between the two times before and after) is greater than a first threshold, it may be determined that a measured temperature of the pitch motor is suddenly changed. Alternatively, when the difference between the temperatures of the pitch motors at the front and rear times is greater than the second threshold, it may be determined that the measured temperature of the pitch motor is suddenly changed. Here, the first threshold value may be, for example, 3, and the second threshold value may be, for example, 100 ℃, but the values of the first threshold value and the second threshold value are not limited thereto, but may be set by those skilled in the art according to the actual situation.

According to embodiments of the present disclosure, a representative difference of a given pitch speed from an actual pitch speed over a predetermined period of time may be determined by. First, an average value of a given pitch speed over a predetermined period of time may be determined, and an average value of an actual pitch speed over the predetermined period of time is determined. The difference between the average of a given pitch speed and the average of the actual pitch speeds may then be taken as a representative difference. Assuming that there are sampling moments (hereinafter simply referred to as moments) of n pitch controllers in a predetermined period of time, a sum SumA of the given pitch speeds in the predetermined period of time can be obtained by adding the given pitch speeds of the n moments, a sum SumB of the actual pitch speeds in the predetermined period of time can be obtained by adding the actual pitch speeds of the n moments, and an average value of the given pitch speeds in the predetermined period of time (i.e., sumA/n) and an average value of the actual pitch speeds (i.e., sumB/n) can be obtained by dividing SumA and SumB by n, respectively. The pitch controller may obtain a given pitch speed from the main controller of the wind turbine and may use various sensors to detect the actual pitch speed.

Alternatively, a representative difference of a given pitch speed and an actual pitch speed over a predetermined period of time may also be determined by. First, the difference between a given pitch speed and an actual pitch speed at various times within a predetermined period of time may be determined. The average of the differences between a given pitch speed and the actual pitch speed at each instant may then be taken as a representative difference.

It is noted that when determining a representative difference of a given pitch speed and an actual pitch speed over a predetermined period of time, the predetermined period of time starts from a previous time when the measured temperature of the pitch motor was suddenly changed. In other words, the first moment in time when the pitch controller samples during the predetermined period of time is the moment before the moment when the measured temperature of the pitch motor suddenly changes.

Next, in step S502, based on the representative difference, a theoretical temperature of the pitch motor at the end time of the predetermined period of time is determined from a predetermined correspondence of the pitch speed difference and the temperature change rate.

A method of determining the correspondence of the pitch speed difference value and the temperature change rate is first described below.

Fig. 6 is a flowchart illustrating a method of determining a correspondence of a difference between a given pitch speed and an actual pitch speed (i.e., a pitch speed difference) and a temperature change rate according to an embodiment of the present disclosure. The method shown in fig. 6 may be performed by a pitch controller or a main controller of the wind power plant, or any other controller provided in the wind power plant.

Referring to fig. 6, in step S601, a rate of change of a measured temperature of the pitch motor for each time interval within a preset history period may be determined, and an average value of differences of actual pitch speeds from a given pitch speed for each time interval may be determined. Here, the duration of the preset history period is on the order of minutes (for example, but not limited to, 10 minutes), and the duration of each time interval within the preset history period is on the order of seconds (for example, but not limited to, 8 seconds). Each time interval may include a plurality of sampling instants (hereinafter referred to as instants). The method comprises the steps that in the first N time intervals in a preset historical time period, a variable-pitch motor is in a normal running state, in the other M time intervals in the preset historical time period, the variable-pitch motor is in a locked-rotor state, N and M are integers larger than 1, and N is smaller than M. Therefore, the change rate of the measured temperature of the variable pitch motor at each time interval in the preset historical time period can reflect the normal change of the measured temperature when the variable pitch motor normally operates and the rapid change of the measured temperature when the variable pitch motor is locked, so that the corresponding relation between the determined variable pitch speed difference value and the temperature change rate covers more working conditions, and the application range is wider.

According to an embodiment of the present disclosure, in order to determine a rate of change of a measured temperature of a pitch motor for each time interval within a preset history period, a correction value of the measured temperature at each time in the time interval may be first determined for each interval. Specifically, for each time in the time interval, if the measured temperature at the time is smaller than the measured temperature at the time immediately before the time, the measured temperature at the time immediately before the time may be taken as the correction value of the measured temperature at the time, and if the measured temperature at the time is greater than or equal to the measured temperature at the time immediately before the time, the measured temperature at the time may be taken as the correction value of the measured temperature at the time directly. Thereafter, the rate of change of the measured temperature for each time interval may be determined based on the correction value of the measured temperature at the end time of each time interval and the measured temperature at the initial time of the preset history period. For example, the ratio of the correction value of the measured temperature at the end time of each time interval to the measured temperature at the initial time of the preset history period may be determined as the rate of change of the measured temperature for each time interval. Here, the purpose of determining the correction value of the measured temperature at each time is to acquire a one-way large value of the measured temperature to remove the influence of fluctuation of the measured temperature. Meanwhile, the change rate of the measured temperature is determined by taking the time interval as a unit, so that the data required for determining the corresponding relation between the variable pitch speed difference value and the temperature change rate is reduced, and the data operation is facilitated.

Fig. 7 is a graph showing measured temperatures of a pitch motor and correction values thereof over a certain time interval. Referring to fig. 7, a curve 701 represents an original measured temperature, a curve 702 represents a correction value of the measured temperature, an abscissa represents a time value, and an ordinate represents a temperature value. As shown in fig. 7, in the case where the original measured temperature is jumped up and down, a deviation is easily caused when the rate of change of the measured temperature is determined. For example, if the rate of change of the measured temperature is determined at times 332 and 345, a negative value is likely to be obtained. For this purpose, the curve 702 can be obtained by correcting the original measured temperature. In addition, for protecting the pitch motor, even if the calculated temperature is high (for example, the actual temperature is 50 ℃ and the calculated temperature is 52 ℃), the purpose of protecting the motor can be achieved, but if the calculated temperature is low (for example, the actual temperature is 50 ℃ and the calculated temperature is 47 ℃), potential safety hazards may be caused.

Referring back to fig. 6, in step S602, curve fitting may be performed based on the rate of change of the measured temperature of the pitch motor for each time interval and the average value of the difference between the actual pitch speed and the given pitch speed for each time interval, to obtain the correspondence between the pitch speed difference and the temperature rate of change. Here, various curve fitting methods may be used to obtain the correspondence of the pitch speed difference value and the temperature change rate, which is not limited in this disclosure.

Table 1 exemplarily shows the rate of change of the measured temperature of the pitch motor for a plurality of time intervals and the average value of the differences of the actual pitch speed from a given pitch speed over the respective time intervals.

TABLE 1

Fig. 8 is a graph showing a correspondence relationship between a pitch speed difference value and a temperature change rate obtained by curve fitting.

Referring to fig. 8, a curve 801 represents a correspondence between a pitch speed difference value and a temperature change rate, and a horizontal axis represents a pitch speed difference value and a vertical axis represents a temperature change rate. Here, the pitch speed difference and the temperature change rate shown in fig. 8 use the data given in table 1.

Returning to step S502, if the representative difference (e.g., average value of the pitch speed differences) within the predetermined period is X, and the temperature change rate corresponding to X is determined to be Y by the curve 801, the theoretical temperature t=a×y of the pitch motor at the end time of the predetermined period, where a represents the measured temperature of the pitch motor at the start time of the predetermined period (i.e., the time immediately before the measured temperature of the pitch motor suddenly changed). However, if the average value of the pitch speed difference value within the predetermined period of time does not coincide with a point on the abscissa of the curve 801, for example, the average value of the pitch speed difference value is 2.8, which is between the 7 th point and the 8 th point, the corresponding temperature change rate may be calculated by a two-point equation according to the correspondence between the pitch speed difference value and the temperature change rate, for example, (X-2.748489)/(3.186793-2.748489) = (Y-1.246996)/(1.279349-1.246996), and substituting x=2.8, the corresponding temperature change rate y= 1.250798 may be obtained. If the measured temperature a=30℃ of the pitch motor at the start time of the predetermined period, the theoretical temperature t=30℃ x 1.25=37.5 ℃ of the pitch motor at the end time of the predetermined period.

In step S503, the pitch system is controlled to enter a redundant operating mode in response to the theoretical temperature being less than or equal to a preset temperature threshold. Alternatively, a wind turbine generator set shutdown may be triggered in response to the theoretical temperature being greater than a preset temperature threshold. Here, the preset temperature threshold may be, for example, a failure threshold 140 ℃, but the present disclosure is not limited thereto. The preset temperature threshold may be set to be above or below 140 ℃.

The redundant operation mode may also be referred to as a fault tolerant operation mode, in which the pitch system may be controlled to take up a predetermined angle while the wind turbine may remain in a grid-connected mode. The operation duration of the redundant operation mode may be 5 to 10 minutes, but is not limited thereto. If the variable pitch system exits the redundant operation mode, the temperature sensor of the variable pitch motor is in a normal operation state, and the measured temperature of the variable pitch motor is smaller than or equal to a preset temperature threshold value, the variable pitch system can be controlled to normally operate. However, if the temperature sensor of the pitch motor is in an abnormal operating state or the measured temperature of the pitch motor is greater than a preset temperature threshold when the pitch system exits the redundant operating mode, a wind turbine generator system fault shutdown may be triggered. Here, the pitch controller may determine an operating state of the temperature sensor based on a state signal fed back by the temperature sensor. For example, if the measured temperature of the pitch motor is restored to a normal temperature from a sudden change state before entering the redundant operation mode (i.e., the temperature sensor is restored to a normal operation state) when the pitch system exits the redundant operation mode, and the measured temperature does not exceed a preset temperature threshold, the pitch system may be operated normally. However, if the measured temperature of the pitch motor is still in a sudden change state (i.e., the temperature sensor is in an abnormal operation state) when the pitch system exits the redundant operation mode, or although the measured temperature of the pitch motor is restored to a normal temperature from the sudden change state before entering the redundant operation mode, the measured temperature of the pitch motor exceeds a preset temperature threshold, a wind turbine generator set malfunction may be triggered.

Alternatively, during the redundant mode of operation, the theoretical temperature of the pitch motor may continue to be determined from a predetermined correspondence of pitch speed difference values to temperature change rates. For example, the operating duration of the redundant operating mode may be divided into a plurality of time periods (e.g., without limitation, a plurality of predetermined time periods as described above), and then the theoretical temperature of the pitch motor may be determined from time period to time period. Specifically, assuming that the theoretical temperature of the pitch motor when the redundant operation mode starts is a (i.e., the theoretical temperature of the pitch motor at the end time of the predetermined period determined in step S502), if the pitch speed difference value in the first period is X1 and the temperature change rate corresponding thereto is Y1, the theoretical temperature t1=a×y1 of the pitch motor at the end time of the first period; if the pitch speed difference value in the second time period is X2 and the corresponding temperature change rate is Y2, the theoretical temperature t2=t1×y2=a×y1×y2 of the pitch motor at the end time of the second time period; similarly, if the pitch speed difference in the nth period is XN and the temperature change rate corresponding thereto is YN, the theoretical temperature tn=a×y1×y2× … … ×yn of the pitch motor at the end of the nth period. On the other hand, if the theoretical temperature of the pitch motor at the end time of any one time period exceeds the preset temperature threshold, the wind generating set can be triggered to stop in a fault mode so as to avoid burning the pitch motor.

According to the pitch control method of the wind turbine generator system, when the temperature sensor of the pitch motor is abnormal and the current value of the pitch motor cannot be obtained, the temperature value of the pitch motor can be accurately predicted only according to the given pitch speed and the actual pitch speed of the pitch system, so that redundant operation of the pitch system is realized on the premise of ensuring operation safety of the wind turbine generator system, and the loss of generated energy is reduced. Meanwhile, the temperature value of the variable-pitch motor can be accurately predicted under the condition that the temperature sensor of the variable-pitch motor is abnormal and the current value of the variable-pitch motor cannot be obtained, so that the variable-pitch motor can be effectively prevented from being burnt out due to overhigh temperature, and the component loss and the cost loss of the wind generating set are reduced.

Fig. 9 is a block diagram illustrating a controller according to an embodiment of the present disclosure. The controller may be implemented as a respective pitch controller of a wind power generation set.

Referring to fig. 9, a controller 900 according to an embodiment of the present disclosure includes a processor 910 and a memory 920. The processor 910 may include, but is not limited to, a Central Processing Unit (CPU), a Digital Signal Processor (DSP), a microcomputer, a Field Programmable Gate Array (FPGA), a system on a chip (SoC), a microprocessor, an Application Specific Integrated Circuit (ASIC), etc. The memory 920 may store computer programs to be executed by the processor 910. Memory 920 may include high-speed random access memory and/or non-volatile computer-readable storage media. When the processor 910 executes a computer program stored in the memory 920, a pitch control method of a wind turbine generator set as described above may be implemented.

Alternatively, controller 900 may communicate with other various components in the wind park in a wired or wireless communication manner, and may also communicate with other devices in the wind park (e.g., a master controller of the wind park) in a wired or wireless communication manner. In addition, the controller 900 may communicate with devices external to the wind farm in a wired or wireless communication.

FIG. 10 is a control topology of a pitch system of a wind turbine according to an embodiment of the present disclosure.

Referring to fig. 10, three blades (blades 1001, 1002 and another blade not shown in fig. 10) of a wind turbine are mounted on a hub 1003. Pitch controller 1005 and pitch drive 1006 are mounted in pitch control cabinet 1004. Pitch controller 1005 receives pitch commands from a main controller 1008 mounted within nacelle 1009 via a communication line 1010 (e.g., without limitation, a DP communication circuit) and sends pitch speed setpoint to pitch drive 1006, which pitch drive 1006 drives pitch motor 1007 into operation in accordance with the pitch speed setpoint, thereby effecting pitch operation. In addition to communication lines 1010, power supply lines, safety chain lines, and other hardware control lines may be provided between main controller 1008 and pitch controller 1005. Pitch controller 1005 may be implemented by controller 900 as shown in FIG. 9.

Referring to fig. 11, a graph 1101 represents a graph of measured temperature of a pitch motor, and a graph 1102 represents a graph of theoretical temperature of the pitch motor. The abscissa represents time and the ordinate represents temperature value. As shown in fig. 11, at time point 90, the measured temperature of the pitch motor jumps to 850 ℃, and returns to the normal value around time point 240. From time point 80, a theoretical temperature of the pitch motor is determined from a predetermined correspondence of pitch speed difference and temperature change rate. When the measured temperature of the variable-pitch motor is recovered to be normal, the deviation between the theoretical temperature and the measured temperature is less than 10 ℃, and the feasibility of determining the theoretical temperature of the variable-pitch motor according to the corresponding relation between the variable-pitch speed difference value and the temperature change rate is fully proved.

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

According to an embodiment of the present disclosure, there may also be provided a wind power generating set comprising a controller as described above.

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

Claims

1. The pitch control method of the wind generating set is characterized by comprising the following steps of:

determining a representative difference of a given pitch speed and an actual pitch speed over a predetermined period of time in response to a measured temperature of the pitch motor abrupt during a pitch operation;

determining a theoretical temperature of the pitch motor at the end time of the preset time period according to a preset corresponding relation between the pitch speed difference value and the temperature change rate based on the representative difference value;

and controlling the pitch system to enter a redundant operation mode in response to the theoretical temperature being less than or equal to a preset temperature threshold.

2. A method of pitch control of a wind turbine according to claim 1, wherein the measured temperature of the pitch motor is determined to be suddenly changed in response to the rate of change of the temperature of the pitch motor at both the front and rear instants being greater than a first threshold value and/or the difference between the temperatures of the pitch motor at both the front and rear instants being greater than a second threshold value.

3. The pitch control method of a wind turbine according to claim 1, wherein the pitch control method further comprises:

and triggering the wind generating set to stop in a fault mode in response to the theoretical temperature being greater than a preset temperature threshold.

4. A method of pitch control of a wind power plant according to claim 1, wherein the step of determining a representative difference of a given pitch speed and an actual pitch speed over a predetermined period of time comprises:

determining an average value of a given pitch speed over the predetermined period of time, and determining an average value of an actual pitch speed over the predetermined period of time;

the difference between the average value of the given pitch speed and the average value of the actual pitch speed is taken as the representative difference.

5. A method of pitch control of a wind power plant according to claim 1, wherein the step of determining a representative difference of a given pitch speed and an actual pitch speed over a predetermined period of time comprises:

determining a difference between a given pitch speed and an actual pitch speed at each moment in the predetermined time period;

the average of the differences between a given pitch speed and the actual pitch speed at each instant is taken as the representative difference.

6. A pitch control method of a wind turbine according to claim 4 or 5, wherein the predetermined period of time starts from a time before a time when a measured temperature of the pitch motor suddenly changes.

7. The pitch control method of a wind turbine according to claim 1, wherein the correspondence between the pitch speed difference and the temperature change rate is determined by:

determining a change rate of a measured temperature of the pitch motor for each time interval within a preset historical time period, and determining an average value of differences between an actual pitch speed and a given pitch speed for each time interval;

and performing curve fitting based on the change rate of the measured temperature of the pitch motor at each time interval and the average value of the difference value between the actual pitch speed and the given pitch speed at each time interval to obtain the corresponding relation between the pitch speed difference value and the temperature change rate.

8. The method for controlling pitch control of a wind turbine according to claim 7, wherein the step of determining a rate of change of the measured temperature of the pitch motor for each time interval within the preset historical period of time comprises:

determining a correction value of a measured temperature at each time in any one time interval, wherein, for any one time, if the measured temperature at any one time is smaller than the measured temperature at the previous time of any one time, the measured temperature at the previous time of any one time is taken as the correction value of the measured temperature at any one time, and if the measured temperature at any one time is greater than or equal to the measured temperature at the previous time of any one time, the measured temperature at any one time is taken as the correction value of the measured temperature at any one time;

and determining the change rate of the measured temperature of any one time interval based on the corrected value of the measured temperature at the ending time of the any one time interval and the measured temperature at the initial time of the preset historical time interval.

9. The method for controlling pitch of a wind turbine according to claim 7, wherein the pitch motor is in a normal operation state for the first N time intervals within the predetermined history period, and the pitch motor is in a locked state for the remaining M time intervals within the predetermined history period,

wherein N and M are integers greater than 1 and N is less than M.

10. The pitch control method of a wind turbine according to claim 7, wherein the duration of the preset history period is in the order of minutes, and the duration of each time interval in the preset history period is in the order of seconds.

11. A computer readable storage medium storing a computer program, characterized in that the pitch control method according to any one of claims 1 to 10 is implemented when the computer program is executed by a processor.

12. A controller, the controller comprising:

a processor; and

memory storing a computer program which, when executed by a processor, implements a pitch control method according to any one of claims 1 to 10.

13. A wind power plant, characterized in that the wind power plant comprises a controller according to claim 12.