JP2006296189A - Generator control method and device of wind power generating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a generator control method for improving a capacity operating rate of the generator, while the rotation of a windmill is slowing down without using external devices, even if the number of rotations rises excessively by excessive wind velocity. <P>SOLUTION: A windmill 10, a generator 20, a converter 30 having a torque command pattern, according to the generator for controlling the generator, and an inverter 40 for converting the output of the converter to a prescribed voltage and frequency and generating as outputs to the system are provided. A protection torque command pattern is formed in a region, in which the number of rotations which is lower than the maximum torque point of the windmill at given wind velocity; and a protection detection level for shifting from the torque command pattern to the protection torque command pattern, when the number of rotations of the generator 20 is increased, is set. Furthermore, a recovery detection level for recovering to the torque command pattern, when the number of rotations of the generator 20 is decreased, is set. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a generator control method and apparatus for a wind turbine generator that converts wind power into electric power.

In the conventional wind turbine generator, when the rotational speed increases excessively due to excessive wind speed such as storm, the wind turbine is decelerated by an electric brake or a mechanical brake in order to prevent damage to the wind turbine (for example, Non-Patent Document 1). reference).
There is also a generator control that maintains a constant torque by decreasing the torque command value in a region where the wind speed energy is small relative to the target torque command value and increasing the torque command value in a region where the wind speed energy is large ( For example, see Patent Document 1).
There is also a generator control in which a maximum output is taken out at a low wind speed and a leveled output is taken out at a high wind speed (see, for example, Patent Document 2).
There is also a generator control that schedules the output of a wind turbine that can be output based on wind condition prediction information, controls the pitch of the wind turbine blades and the power converter, and takes out a predetermined output (see, for example, Patent Document 3). .

FIG. 4 is a block diagram showing a conventional wind power generator according to the principle of Non-Patent Document 1.
In the figure, 11 is a windmill, which converts the energy of the wind 10 into rotational energy. A generator 20 converts the rotational energy of the windmill 11 into alternating electrical energy. Reference numeral 30 denotes a converter that converts the alternating current extracted by controlling the generator 20 into a direct current and outputs 31 to the DC link. Reference numeral 40 denotes an inverter that converts direct current into alternating current having a predetermined voltage and frequency and outputs the alternating current to the system. Reference numeral 50 denotes a controller composed of a sequencer or the like, which monitors the rotational speed of the generator 20 via the converter 30 and operates the brake 60 when the rotational speed of the generator 20 increases excessively at an excessive wind speed. Slow down.
Thus, in the conventional wind power generator, the procedure of preventing the windmill 11 from being damaged at excessive wind speed by decelerating the windmill 11 by the brake 60 has been taken.

Yuji Sato, “Development of small wind power generation“ Soyoka-kun (registered trademark) ”, IEEJ Transactions on Industrial Applications, Vol. 124 No. 9 2004 p. 976 Japanese Patent Laid-Open No. 11-62814 (page 4-6, FIG. 2) JP 2004-64929 A (page 4-6, FIGS. 1 and 2) Japanese Patent Laying-Open No. 2003-83229 (page 4-6, FIG. 1)

Thus, in the conventional wind power generator, when the rotation speed increases excessively due to excessive wind speed, the procedure is that the wind turbine is decelerated by the brake 60, so that the power generator becomes complicated and reliability decreases. There was a problem.
Further, when the decelerated rotation by the brake 60 is performed for a long time, the brake 60 is overheated or wears severely, so that the decelerated rotation cannot be maintained.
Furthermore, when the windmill 11 is stopped in order to avoid overheating and wear of the brake 60, there is a problem that the windmill 11 is damaged by the wind pressure.
When the brake 60 is operated due to an excessive wind speed, the operation rate of the power generation apparatus is reduced because the brake 60 is manually returned when returning to normal operation.
Further, as in the invention described in Patent Document 1, the torque command value is decreased in a region where the wind speed energy is small relative to the target torque command value, and the torque command value is decreased in a region where the wind speed energy is large.
When the constant torque is maintained by increasing, there is a problem that the generator 20, the converter 30 and the inverter 40 are overloaded when the wind speed is excessive and cannot be controlled due to overheating.
Similarly, when the maximum output is taken out at a low wind speed and the leveled output is taken out at a high wind speed as in the invention described in Patent Document 2, the generator 20, the converter 30 and the inverter 40 are connected at an excessive wind speed. There was a problem that it became overloaded operation and became uncontrollable due to overheating.
And like invention of patent document 3, when the output of the windmill 11 which can be output by wind condition prediction information is scheduled, the pitch of a windmill blade and a power converter are controlled, and a predetermined output is taken out, Since measures are taken to decelerate the windmill by adjusting the pitch of the blades, there is a problem that the power generation device becomes complicated and reliability is lowered.

  The present invention has been made in view of such problems, and can reduce the rotation of the windmill 11 without using an external device such as the brake 60, and can improve the operating rate of the power generation device. An object of the present invention is to provide a generator control method and apparatus therefor.

In order to solve the above problem, the invention according to claim 1 relates to a generator control method for a wind turbine generator, and includes a wind turbine, a generator, and a torque command pattern corresponding to the rotation of the generator to control the generator. In a generator control method for a wind turbine generator comprising a converter that performs the conversion and an inverter that converts the output of the converter into a predetermined voltage and frequency and outputs the converted voltage to the system, the maximum torque of the wind turbine at a certain wind speed is obtained. In addition, a protective torque command pattern is provided in a region of a lower rotational speed, and when the rotational speed of the generator exceeds a predetermined value, the torque command pattern is shifted to the protective torque command pattern.
According to a second aspect of the present invention, in the generator control method for a wind turbine generator according to the first aspect, when the number of rotations of the generator is reduced by the control with the protective torque command pattern, the torque is reduced from the protective torque command pattern. It is characterized by returning to the command pattern.

The invention according to claim 3 relates to a generator control method for a wind turbine generator, comprising a wind turbine, a generator, a converter having a protective torque command pattern corresponding to the rotation of the generator, and controlling the generator, An inverter for converting the output of the converter into a predetermined voltage and frequency and outputting to the system, a generator control method for a wind turbine generator, wherein the protection torque command pattern determined according to the rotation of the generator When driving normally at a wind speed less than a predetermined level in the configuration given by the torque command T_ref = K · f (ω) as a product of the function f (ω) of the speed ω, including the gain K as a determining factor Is operated at a normal gain Knorm, and when the wind speed exceeds a predetermined level, it is determined that the predetermined level has been exceeded, and when it is determined that the predetermined level has been exceeded, the maintenance is performed. When it is determined that the number of revolutions has decreased by increasing the gain that determines the protective torque command pattern by a predetermined amount and the gain has been increased, and the generator torque has become smaller than the predetermined level, at that time It is characterized in that the operation is continued with the gain fixed at the magnitude of the gain.
According to a fourth aspect of the present invention, in the generator control method for a wind turbine generator according to the third aspect, when the wind power is reduced to a normal level by the control with the protection torque command pattern, the state of the generator torque is indicated. The torque gain K is detected by being lower than a predetermined level, and the torque gain K is returned to the normal gain Knorm to return to the normal operation state.

The invention according to claim 5 relates to a generator control device for a wind turbine generator, and includes a wind turbine, a generator, a converter having a torque command pattern corresponding to the rotation of the generator, and controlling the generator, and the converter In a generator control method for a wind turbine generator that includes an inverter that converts the output of the wind turbine into a predetermined voltage and frequency and outputs it to the grid, it is lower than the point at which the maximum torque of the wind turbine is obtained at a certain wind speed.
A protection torque command pattern is provided in a region of a large number of revolutions, and a protection detection level is provided that shifts from the torque command pattern to the protection torque command pattern when the number of revolutions of the generator increases.
According to a sixth aspect of the present invention, in the generator control device for a wind turbine generator according to the fifth aspect, in the control with the protective torque command pattern, when the rotational speed of the generator decreases, the protective torque command pattern A return detection level for returning to the torque command pattern is provided.

The invention according to claim 7 relates to a generator control device of a wind power generator, and includes a wind turbine, a generator, a converter having a torque command pattern according to rotation of the generator, and controlling the generator, and the converter A generator control device for a wind turbine generator that includes an inverter that converts the output of the output into a predetermined voltage and frequency and outputs the converted voltage to the system, and determines the torque command pattern determined according to the rotation of the generator In the configuration given by the torque command T_ref = K · f (ω) as a product of the function ω (ω) of the speed ω as a product with the gain K as A gain increasing unit that increases the gain that determines the torque command pattern by a predetermined change amount, a gain fixing unit that fixes the magnitude of the gain to the gain at that time, and a wind speed of a predetermined level A wind speed determination unit that determines whether or not the generator torque is exceeded, and a generator torque determination unit that determines whether or not the generator torque is at a predetermined level, and when the wind speed determination unit determines that the wind speed is less than the predetermined level, the normal time If the wind speed determination unit determines that the wind speed has exceeded a predetermined level, the gain increase unit is operated to increase the gain, thereby reducing the rotational speed. When the generator torque determination unit determines that the generator torque has become smaller than a predetermined level, the gain fixing unit is operated so that the operation is continued with the magnitude of the gain at that time. It is said.
The invention according to claim 8 is the generator control device for the wind turbine generator according to claim 7, further comprising a wind power normal level determination unit that determines whether the wind power is at a normal level in the control with the protection torque command pattern. When the wind power normal level determination unit determines that the wind power has decreased to a normal level, and the generator torque determination unit determines that the generator torque has become smaller than a predetermined level, the low gain operation for normal operation is performed. And the torque gain K is returned to the normal gain Knorm to return to the normal operation state.
According to a ninth aspect of the present invention, in the generator control device for a wind turbine generator according to the third aspect, it has been determined that by increasing the gain, the rotational speed has decreased and the generator torque has become smaller than a predetermined level. In this case, the operation is continued with the rotation speed of the generator being constant at the rotation speed at that time.
The invention described in claim 10 is the generator control device of the wind turbine generator according to claim 9, wherein when the wind power drops to a normal level, the generator torque becomes smaller than a predetermined level. And returning to the normal operation state by the process of returning the torque gain K to the normal gain Knorm.
The invention described in claim 11 is the generator control device for a wind turbine generator according to claim 9, wherein when the state where the wind speed exceeds the predetermined level continues for a predetermined time, it is determined that the predetermined level has been exceeded. It is characterized by this.
According to a twelfth aspect of the present invention, in the generator control device for a wind turbine generator according to the tenth aspect, when the state in which the generator torque is smaller than a predetermined level continues for a predetermined time, the wind power is at a normal level. It is characterized by determining that it has decreased.

According to the first and fifth aspects of the present invention, the rotation of the windmill can be decelerated at an excessive wind speed only by the generator control without using an external device such as a brake, and the power generator is simplified and the reliability is improved. Can do.
Further, since the windmill is not stopped at an excessive wind speed, the windmill is not damaged.
Further, according to the second and sixth aspects of the invention, it is possible to automatically return to normal operation, continue the operation without stopping the windmill, and improve the operating rate of the power generator.

According to the third and seventh aspects of the invention, since the procedure for shifting from the normal torque command pattern to the protective torque command pattern is taken in the control of the converter, the excessive wind speed is controlled only by the generator control without using an external device such as a brake. Sometimes the rotation of the windmill can be decelerated, and the power generator can be simplified to improve reliability.
Further, since the windmill is not stopped at an excessive wind speed, the windmill is not damaged.
Further, according to the inventions of claims 4 and 8, since the procedure for returning from the protective torque command pattern Ter to the normal torque command pattern Tnorm is taken, it automatically returns to normal operation without stopping the windmill. The operation can be continued and the operating rate of the power generator can be improved.
According to the ninth aspect of the present invention, the rotation of the windmill can be decelerated at an excessive wind speed only by the generator control without using an external device such as a brake, and the power generator can be simplified and the reliability can be improved. . Further, since the windmill does not over-rotate at an excessive wind speed and does not stop the wind turbine, an excessive force is not applied to the wind turbine and the wind turbine is not damaged. In addition, since the wind turbine is operated in a low rotational speed region when the wind speed is excessive, the power generator is not overloaded and cannot be controlled due to overheating.
According to the invention described in claim 10, it is possible to automatically return to normal operation, continue the operation without stopping the windmill, and improve the operating rate of the power generator.
Further, according to the invention described in claim 11, it is not determined that the predetermined level has been exceeded due to instantaneous wind power fluctuation, and according to the invention described in claim 12, the predetermined level is determined by instantaneous wind power fluctuation. Therefore, it is possible to continue the operation in which the rotation of the windmill is decelerated stably during normal operation or excessive wind speed.

  Hereinafter, specific examples of the method of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a wind turbine generator that performs a method according to Embodiment 1 of the present invention. In the figure, 11 is a windmill, which converts the energy of the wind 10 into rotational energy. A generator 20 is directly connected to the windmill 11 or connected via a gear or the like, and converts the rotational energy of the windmill 11 into alternating electrical energy. Reference numeral 30 denotes a converter that converts the alternating current extracted by controlling the generator 20 into a direct current and outputs the direct current to the DC link 31. Reference numeral 40 denotes an inverter that converts direct current into alternating current having a predetermined voltage and frequency and outputs the alternating current to the system.

FIG. 2 is a graph showing the torque command pattern of the present invention and the characteristics of the rotational speed, torque and output of the windmill 11, wherein (a) is the rotational speed of the windmill versus torque characteristics, and (b) is the rotational speed of the windmill versus output characteristics. It is.
In the figure, WT1 in (a) is a torque characteristic of the wind turbine 1 at a certain wind speed 1, and WP1 in (b) is an output characteristic at that time. Similarly, WT2 and WP2, WT3 and WP3, and WT4 and WP4 are the torque characteristics and output characteristics of the wind turbine 11 at the wind speed 2, the wind speed 3, and the wind speed 4, respectively. The wind speed increases in the order of wind speed 1 <wind speed 2 <wind speed 3 <wind speed 4. The wind speed 1, the wind speed 2, and the wind speed 3 are normal wind speeds, and the wind speed 4 is an excessive wind speed that exceeds the normal wind speed. The rotational speed of the generator increases or decreases in proportion to the rotational speed of the windmill. Tnorm is a normal torque command pattern, which is a torque command corresponding to the rotational speed of the generator. Pnorm is an output of the wind turbine 11 obtained as a result of performing the generator control by a normal torque command pattern. Ter is a protection torque command pattern, and Per is an output of the wind turbine 11 obtained as a result of performing generator control by the protection torque command pattern.
FIG. 3 is a flowchart showing a processing procedure for shifting from the normal torque command pattern to the protective torque command pattern and returning in the control method of the present invention.

The method of the present invention will be described step by step with reference to FIGS.
In normal times, the wind 10 fluctuates between the wind speed 1, the wind speed 2, and the wind speed 3.
The converter 30 controls the generator 20 with a normal torque command pattern Tnorm, and takes out the outputs of Pn1, Pn2, and Pn3 from the windmill 11 according to the torque commands of Tn1, Tn2, and Tn3 according to the wind speed. At this time, the converter 30 monitors the state of the generator 20 by calculating the rotational speed and power of the generator 20 and the torque output from the windmill 11 by calculation from the voltage and current output from the generator 20. .
Next, when the wind speed rises and the wind speed 4 is an excessive wind speed, the rotational speed of the windmill 11 rises and the torque command value also rises to Tn4. At this time, since the rotational speed exceeds the protection detection level ωer, the converter 30 determines that the wind speed is excessive, and starts the transition from the normal torque command pattern Tnorm to the protection torque command pattern Ter.
Next, a procedure for shifting from the normal torque command pattern Tnorm to the protection torque command pattern Ter will be described. When the rotational speed rises above the protection detection level and reaches T1 due to the wind speed 4, the converter 30 outputs a torque command having a torque command value that is a small amount ΔT larger than T1. When a torque command of T1 + ΔT is given by the converter 30, the torque that can be output from the windmill 11 is T1, and therefore the torque that decelerates ΔT is applied to the windmill 11 and the rotational speed decreases. When the rotational speed of the windmill 11 decreases, the torque that can be output by the windmill 11 increases. Therefore, the converter 30 further increases the torque command value by ΔT and outputs a torque command of T1 + 2ΔT. By repeating this procedure and gradually increasing the torque command value, the rotational speed of the wind turbine 11 decreases.

Next, when the rotational speed of the windmill 11 decreases, the torque that can be output from the increased windmill 11 starts to decrease with Tm as the maximum. Since the converter 30 obtains and monitors the rotational speed of the generator 20 and the torque output from the wind turbine 11, the wind turbine 1 before and after the torque command is increased by ΔT.
By comparing the torque output by 1, it is possible to detect that the torque that can be output from the wind turbine 11 has started to decrease.
When the torque that can be output from the windmill 11 begins to decrease, the rotational speed of the windmill 11 rapidly decreases as the torque command of the converter 30 increases. For this reason, when converter 30 detects that the torque that can be output from wind turbine 11 starts to decrease, it fixes the torque command to the torque command value at that time. Since the torque command value at this time is larger than Tm, even if the torque command value is fixed, the rotational speed of the windmill 11 decreases, and the windmill 11 decreases as the rotational speed of the windmill 11 decreases. The output torque also decreases.

Next, as the rotational speed decreases, the torque output from the windmill 11 also decreases. When it falls below the torque command value Tn3 at the normal wind speed 3, the output becomes smaller than Pn3, and the generator 20, the converter 30, and the inverter 40 can be normally operated without overheating. For this reason, the protection torque command pattern Ter is set as a torque command pattern when the torque output from the windmill 11 falls below Tn3. Since the torque command pattern is usually a characteristic that can be expressed by a simple expression such as a characteristic proportional to the square of the rotational speed, the protection torque command pattern Ter is output from the rotational speed at the time of setting and the wind turbine 11. It can be easily determined from the torque that is present.
Thereby, it is possible to continue the operation while suppressing the rotational speed of the windmill 11 to a low rotational speed at an excessive wind speed.
Thus, since the procedure of transition from the normal torque command pattern to the protective torque command pattern is taken in the control of the converter 30, the rotation of the wind turbine 11 can be performed at the excessive wind speed only by the generator control without using an external device such as the brake 60. The speed can be reduced, and the power generator can be simplified to improve the reliability. Moreover, since the windmill 11 is not stopped at an excessive wind speed, the windmill is not damaged.

Next, a procedure for returning from the protective torque command pattern Ter to the normal torque command pattern Tnorm will be described.
As the wind speed decreases and the wind speed 4 decreases from the excessive wind speed 4 to the normal wind speed 3, the wind speed 2, and the wind speed 1, the torque output by the windmill 11 decreases and the rotational speed also decreases. Thereby, it turns out that the wind speed fell because the rotation speed of the windmill 11 fell. Therefore, the converter 30 detects that the rotational speed of the windmill 11 has dropped below the return detection level ωres, and returns the torque command pattern from the protection torque command pattern Ter to the normal torque command pattern Tnorm.
Thus, since the procedure for returning from the protective torque command pattern Ter to the normal torque command pattern Tnorm is taken, it is possible to automatically return to the normal operation and continue the operation without stopping the windmill 11. The operating rate of the power generator can be improved.

A method according to the second embodiment of the present invention will be described with reference to FIGS.
In normal times, the wind 10 fluctuates between the wind speed 1, the wind speed 2, and the wind speed 3. The converter 30 controls the generator 20 with a normal torque command pattern Tnorm, and takes out the outputs of Pn1, Pn2, and Pn3 from the windmill 11 according to the torque commands of Tn1, Tn2, and Tn3 according to the wind speed. At this time, the converter 30 monitors the state of the generator 20 by calculating the rotation speed and power of the generator 20 and the torque Twind output from the windmill 11 by calculation from the voltage and current output from the generator 20. Yes. At this time, in FIG. 4, the protection operation transition completion flag is “0” during normal operation, and the processing of “no” condition (S2) is executed in the determination of (S1), which again exceeds the excessive wind force condition. Therefore, the normal torque gain Knorm is used as the torque gain K in the process of (S3), and the torque command T_ref is calculated in the process of (S4).
Next, when the wind speed rises and the wind speed 4 is an excessive wind speed, the rotational speed of the windmill 11 rises and the torque command value also rises to Tn4. At this time, since the rotational speed of the generator exceeds the protection detection level ωer or the torque command T_ref exceeds the protection detection level Ter_lvl, it is determined that the converter 30 has an excessive wind speed (S2), and the normal torque command pattern The transition from Tnorm to the protective torque command pattern Ter is started.

Next, a procedure for shifting from the normal torque command pattern Tnorm to the protection torque command pattern Ter will be described.
When the rotational speed of the generator rises beyond the protection detection level and reaches T1 due to the wind speed 4, an excessive wind condition is detected (S2), the converter 30 adds ΔK to the torque gain K (S5), and then the wind turbine The output torque and the protection torque level are compared (S6). Here, the protection torque level is a torque level for determining that the torque command pattern is a torque command pattern during the protection operation at the time of excessive wind power, and is set to a value smaller than the protection detection level Ter_lvl of the torque command. It is. At first, since the wind turbine output torque> the protection torque level, the control is performed with the value calculated by using the torque gain K obtained by adding ΔK to the torque command T_ref in the above-described process (S5) in the next step.
When the gain K is increased by ΔK, the curve of the torque command pattern Tnorm in FIG. 2 becomes steep and approaches the protective torque command pattern Ter. Therefore, although the torque command T_ref is increased, the torque that can be output by the windmill 11 is T1, and therefore the windmill 11 is subjected to a torque that decelerates as the torque command increases, and the rotational speed of the generator decreases. At this time, the torque Twind of the windmill also increases, but when the rotational speed of the generator decreases and exceeds the peak Tm, it starts to decrease this time.
Subsequently, when the flow of FIG. 4 is executed in the next calculation cycle, the processes of (S1), (S2), (S5), and (S6) are repeated in the same manner, and the wind turbine is subjected to the condition process of (S6). When it is determined that the output torque Twind is lower than the protection torque level, the protection operation transition completion flag is set to “1”.
In the next cycle in which the protection operation transition completion flag is set to “1”, the protection operation transition completion flag is “1” in the processing of (S1), and therefore the return condition detection processing of (S8) is executed. .
The return condition in (S8) is performed by detecting that the output torque Twind of the windmill has fallen below the return detection level Tres_lvl or that the rotational speed of the generator by the windmill 11 has dropped below the return detection level ωres.
Until the return condition is satisfied, the next (S4) is executed without doing anything, so the torque command T_ref is calculated while holding the torque gain K when the protection operation transition is completed.
During the protection operation, as indicated by the protection torque command pattern Ter in FIG. 2, when the torque command value Tn3 at the normal wind speed 3 falls, the output becomes smaller than Pn3, and the generator 20, converter 30, inverter 40 Can operate normally without overheating. Since the torque command pattern is usually a characteristic that can be expressed by a simple expression such as a characteristic proportional to the square of the rotational speed, the normal command torque pattern Tnorm should be set in advance based on the characteristics of the wind turbine. Can do.
Thereby, it is possible to continue the operation while suppressing the rotational speed of the windmill 11 to a low rotational speed at an excessive wind speed.

  Thus, since the procedure for shifting from the normal torque command pattern to the protective torque command pattern is taken in the control of the converter 30, the rotation of the wind turbine 11 at the excessive wind speed is performed only by the generator control without using an external device such as the brake 60. The power generator can be simplified and the reliability can be improved. Moreover, since the windmill 11 is not stopped at an excessive wind speed, the windmill is not damaged.

Next, a procedure for returning from the protective torque command pattern Ter to the normal torque command pattern Tnorm will be described.
As the wind speed decreases and the wind speed 4 decreases from the excessive wind speed 4 to the normal wind speed 3, the wind speed 2, and the wind speed 1, the torque output by the windmill 11 decreases and the rotational speed of the generator also decreases. Thereby, it turns out that the wind speed fell because the rotation speed of the generator by the windmill 11 fell. Therefore,(
If the return condition of S8) is satisfied, the torque gain K is set to Knorm, which is the normal torque command pattern gain, and "0" is set to the protection operation transition completion flag (S9).
In the next cycle, since the protection operation transition completion flag is “0”, the process returns to the normal state process, and the processes (S1), (S2), (S3), and (S4) are executed. Is done.
Thus, since the procedure for returning from the protective torque command pattern Ter to the normal torque command pattern Tnorm is taken, it is possible to automatically return to the normal operation and continue the operation without stopping the windmill 11. The operating rate of the power generator can be improved.

A method according to Embodiment 3 of the present invention will be described with reference to FIGS.
FIG. 6 is a graph showing the torque command pattern of the present invention and the rotational speed, torque and output characteristics of the wind turbine 11.

  In FIG. 6, WT1 is a torque characteristic of the windmill 1 at a certain wind speed 1, and WP1 is an output characteristic at that time. Similarly, WT2 and WP2, WT3 and WP3, and WT4 and WP4 are the torque characteristics and output characteristics of the wind turbine 11 at the wind speed 2, the wind speed 3, and the wind speed 4, respectively. The wind speed increases in the order of wind speed 1 <wind speed 2 <wind speed 3 <wind speed 4. The wind speed 1, the wind speed 2, and the wind speed 3 are normal wind speeds, and the wind speed 4 is an excessive wind speed that exceeds the normal wind speed. The rotational speed of the generator increases or decreases in proportion to the rotational speed of the windmill. Therefore, here, the rotational speed of the windmill and the rotational speed of the generator are used interchangeably. Tnorm is a normal torque command pattern, which is a torque command corresponding to the rotational speed of the generator. Therefore, Tnorm is expressed by the product of the function f (ω) of ω and the torque gain K indicating the slope of the gradient, with the rotational speed ω of the generator as an input, and the torque command T_ref at a certain generator rotational speed ω is T_ref = K・ It is given by f (ω). Pnorm is an output of the wind turbine 11 obtained as a result of performing the generator control by a normal torque command pattern. Ter_lvl is the torque level at which the protection operation starts, and ωer is the rotational speed of the generator that starts the protection operation. Tp_lvl is the torque level of the protected operation condition, and ωp is the rotational speed of the generator under the protected operation condition.

  FIG. 7 is a flowchart showing a processing procedure for shifting from a normal torque command pattern to a protected operation condition and returning in the control method of the present invention. 7 is different from FIG. 4 in that step S10 is provided, and the other parts are the same as those in FIG.

  The method of the present invention will be described step by step with reference to FIGS.

  In normal times, the wind 10 fluctuates between the wind speed 1, the wind speed 2, and the wind speed 3. The converter 30 controls the generator 20 with a normal torque command pattern Tnorm, and takes out the outputs of Pn1, Pn2, and Pn3 from the wind turbine 11 according to the torque commands of Tn1, Tn2, and Tn3 according to the wind speed. At this time, the converter 30 monitors the state of the generator 20 by calculating the rotational speed and power of the generator 20 and the torque Twind output from the windmill 11 by calculation from the voltage and current output from the generator 20. Yes. At this time, in FIG. 7, during normal operation, the protection operation transition completion flag is “0”, and the processing (S2) of the condition of “no” is executed in the determination of (S1), and again the excessive wind force condition is exceeded. Therefore, the normal torque gain Knorm is used as the torque gain K in the process of (S3), and the torque command T_ref is calculated in the process of (S4).

Next, when the wind speed rises to an excessively high wind speed 4, the rotational speed of the windmill 11 rises and the torque command value also rises to Tn4. At this time, if the rotational speed of the generator exceeds the protection detection level ωer or the torque command T_ref exceeds the protection detection level Ter_lvl and a predetermined time has elapsed, the converter 30 determines that the wind speed is excessive. (S2) The transition from the normal torque command pattern Tnorm to the protective operation condition ωp is started.
Here, ωp is the generator rotational speed when the protection operation transition is completed, and the operation is performed so that the generator rotational speed becomes ωp during the protective operation.

  Next, a procedure for shifting from the normal torque command pattern Tnorm to the protective operation condition ωp will be described. When the speed of the generator rises above the protection detection level and reaches Tn4 due to wind speed 4, an excessive wind condition is detected (S2), and converter 30 adds ΔK to torque gain K (S5). The output torque and the protection torque level Tp_lvl are compared (S6). Here, the protection torque level Tp_lvl is a torque level for determining that the wind turbine output torque during the protection operation at the time of excessive wind force has become a predetermined torque, and is set to a value smaller than the protection detection level Ter_lvl of the torque command It is. At first, since the wind turbine output torque> the protection torque level, the control is performed with the value calculated using the torque gain K obtained by adding ΔK to the torque command T_ref in the above-described process (S5) in the next step.

  When the gain K is increased by ΔK, the curve of the torque command pattern Tnorm in FIG. 6 becomes steeper. Therefore, although the torque command T_ref increases, the torque that the wind turbine 11 can output is Tn4. Therefore, the wind turbine 11 is subjected to a torque that decelerates as the torque command increases, and the rotational speed of the generator decreases. At this time, the torque Twind of the windmill also increases, but when the rotational speed of the generator decreases and exceeds the peak Tm, it starts to decrease this time.

  Subsequently, when the flow of FIG. 7 is executed in the next calculation cycle, the processes of (S1), (S2), (S5), and (S6) are repeated in the same manner, and the wind turbine is subjected to the condition process of (S6). When it is determined that the output torque Twind is lower than the protection torque level Tp_lvl, the protection operation transition completion flag is set to “1” (S7), and the rotation speed of the generator at this time is set to ωp.

  In the next cycle when the protection operation transition completion flag is set to "1", the protection operation transition completion flag is "1" in the processing of (S1), so the recovery condition detection processing of (S8) is executed. .

  As for the return condition in (S8), when the output torque Twind of the windmill falls below the return detection level Tres_lvl and a predetermined time has passed, the converter 30 determines that the wind speed is normal.

  Until the return condition is satisfied, the next (S10) is executed without doing anything, so control is performed so that the rotational speed of the generator becomes ωp while maintaining the rotational speed ωp at the completion of the protection operation transition. Do.

  During the protection operation, the wind turbine 11 is operated in the low rotational speed region, so that the output is smaller than Pn3 even if the generator torque is the same as the torque command value Tn3 at the normal wind speed 3, and the generator 20 The converter 30 and the inverter 40 can be normally operated without overheating.

  Thereby, it is possible to continue the operation while suppressing the rotational speed of the windmill 11 to a low rotational speed at an excessive wind speed.

  Thus, since the procedure for shifting from the normal torque command pattern to the protective operation condition is taken in the control of the converter 30, the rotation of the wind turbine 11 can be performed at the excessive wind speed only by the generator control without using an external device such as the brake 60. The speed can be reduced, and the power generator can be simplified to improve the reliability. Moreover, since the windmill 11 is not stopped at an excessive wind speed, the windmill is not damaged. Moreover, normal operation can be continued stably without determining that the predetermined level has been exceeded due to instantaneous wind power fluctuations.

  Next, a procedure for returning from the protective operation condition ωp to the normal torque command pattern Tnorm will be described.

  As the wind speed decreases and the wind speed 4 decreases from the excessive wind speed 4 to the normal wind speed 3, the wind speed 2, and the wind speed 1, the torque output by the windmill 11 decreases. Thereby, it turns out that the wind speed fell. Therefore, when the return condition of (S8) is satisfied, the torque gain K is set to Knorm which is the gain of the normal torque command pattern, and “0” is set to the protection operation transition completion flag (S9).

  In the next cycle, the protection operation transition completion flag is “0”, so the process returns to the normal state and the processes (S1), (S2), (S3), and (S4) are executed. Is done.

  In this way, since the procedure for returning from the protective operation condition ωp to the normal torque command pattern Tnorm is taken, it is possible to automatically return to the normal operation and continue the operation without stopping the windmill 11, The operating rate of the apparatus can be improved. In addition, it is possible to continue the operation under the protected operation condition stably without determining that the level has fallen below the predetermined level due to instantaneous fluctuations in wind power.

The block diagram which shows the structure of the wind power generator which enforces the method of this invention The graph which shows the torque command pattern of this invention, the rotation speed of a windmill, the characteristic of torque, and an output The flowchart which shows the process sequence which transfers and resets from a normal torque command pattern to a protection torque command pattern in the control method of this invention. The flowchart which shows the process sequence which transfers and resets from a normal torque command pattern to a protection torque command pattern in the control method of Example 2. Block diagram showing the configuration of a conventional wind turbine generator The graph which shows the torque command pattern of Example 3, and the rotation speed, torque, and output characteristic of a windmill (generator) The flowchart which shows the process sequence which transfers to a normal driving | running | working protection condition from a normal torque command pattern and returns in the control method of Example 3.

Explanation of symbols

10 wind 11 windmill 20 generator 30 converter 31 DC link 40 inverter 50 controller 60 brake

Claims (12)

A wind turbine, a generator, a converter having a torque command pattern corresponding to the rotation of the generator and controlling the generator, an inverter that converts the output of the converter into a predetermined voltage and frequency, and outputs the voltage to the system In a generator control method of a wind turbine generator comprising:
A protective torque command pattern is provided in a region of a rotational speed lower than the point at which the maximum torque of the wind turbine at a certain wind speed is provided, and the protective torque command pattern is changed from the torque command pattern when the rotational speed of the generator exceeds a predetermined value. The generator control method of the wind power generator characterized by making it transfer to.   2. The wind turbine generator according to claim 1, wherein, in the control with the protection torque command pattern, the torque command pattern returns to the torque command pattern when the rotational speed of the generator decreases. Generator control method. A wind turbine, a generator, a converter having a protective torque command pattern according to the rotation of the generator and controlling the generator, and an inverter that converts the output of the converter into a predetermined voltage and frequency and outputs the voltage to the system A generator control method for a wind turbine generator comprising:
A configuration including a gain K as an element for determining the protection torque command pattern determined according to the rotation of the generator and given by a torque command T_ref = K · f (ω) as a product with the function f (ω) of the speed ω. In the case of normal operation at a wind speed less than a predetermined level, it is operated with a normal gain Knorm, and when the wind speed exceeds a predetermined level, it is determined that the predetermined level has been exceeded, When it is determined that the predetermined level has been exceeded, the gain that determines the protection torque command pattern is increased by a predetermined amount of change, and by increasing the gain, the rotational speed decreases, and the generator torque becomes predetermined. A generator control method for a wind turbine generator, characterized in that, when it is determined that the level is lower than the level, the gain is fixed at that time and the operation is continued.   In the control with the protection torque command pattern, when the wind power decreases to a normal level, the state is detected when the generator torque becomes smaller than a predetermined level, and the torque gain K is determined as the normal gain Knorm. The generator control method for a wind turbine generator according to claim 3, wherein the generator is returned to the normal operation state. A wind turbine, a generator, a converter having a torque command pattern corresponding to the rotation of the generator and controlling the generator, an inverter that converts the output of the converter into a predetermined voltage and frequency, and outputs the voltage to the system In a generator control method of a wind turbine generator comprising:
A protective torque command pattern is provided in the region of the rotational speed lower than the point where the maximum torque of the windmill at a certain wind speed is obtained, and the torque command pattern is shifted to the protective torque command pattern when the rotational speed of the generator is increased. A generator control device for a wind turbine generator, wherein a protection detection level is provided.   6. The wind power according to claim 5, wherein a return detection level for returning from the protective torque command pattern to the torque command pattern when the rotational speed of the generator is lowered is provided in the control with the protective torque command pattern. Generator control device of power generator. A wind turbine, a generator, a converter having a torque command pattern corresponding to the rotation of the generator and controlling the generator, an inverter that converts the output of the converter into a predetermined voltage and frequency, and outputs the voltage to the system A generator control device for a wind turbine generator comprising:
In a configuration including a gain K as an element for determining the torque command pattern determined according to the rotation of the generator, and given by a torque command T_ref = K · f (ω) as a product with a function f (ω) of the speed ω. The normal low-gain operating unit that operates with the normal gain Knorm, the gain increasing unit that increases the gain that determines the torque command pattern by a predetermined change amount, and the magnitude of the gain is fixed to the gain at that time A gain fixing unit, a wind speed determination unit that determines whether or not the wind speed exceeds a predetermined level, and a generator torque determination unit that determines whether or not the generator torque is a predetermined level, wherein the wind speed determination unit is at a predetermined level When it is determined that the wind speed is less than the normal speed, the normal low-gain operation unit is operated, and when the wind speed determination unit determines that the wind speed exceeds a predetermined level, the gay When the gain increase unit is operated and the gain is increased, the rotational speed is decreased, and the gain fixing unit is operated when the generator torque determination unit determines that the generator torque is lower than a predetermined level. The generator control device for a wind turbine generator is characterized in that the operation is continued with the gain at that time.   In the control with the protection torque command pattern, a wind power normal level determination unit that determines whether or not the wind power is at a normal level, the wind power normal level determination unit determines that the wind power has decreased to a normal level, and the power generation When the machine torque determination unit determines that the generator torque has become smaller than a predetermined level, the normal low gain operation unit is operated to return the torque gain K to the normal gain Knorm and return to the normal operation state. The generator control device for a wind turbine generator according to claim 7, wherein   When it is determined that the rotational speed has decreased and the generator torque has become smaller than a predetermined level due to the increase in the gain, the operation is continued with the rotational speed of the generator kept constant at the rotational speed at that time. The generator control method of the wind power generator of Claim 3 characterized by these.   When the wind power drops to a normal level, the state is detected when the generator torque is lower than a predetermined level, and the torque gain K is returned to the normal gain Knorm, and the normal operation state is restored. The generator control method of the wind power generator according to claim 9.   The generator control method for a wind turbine generator according to claim 9, wherein when the state in which the wind speed exceeds the predetermined level continues for a predetermined time, it is determined that the predetermined level has been exceeded.   11. The generator control method for a wind turbine generator according to claim 10, wherein when the state in which the generator torque is smaller than a predetermined level continues for a predetermined time, it is determined that the wind power has decreased to a normal level. .

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