JP2011127480A - Braking device for wind power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a braking device for a wind power generator capable of properly performing braking operation in accordance with an environment. <P>SOLUTION: The problem is solved by having a rotation state detecting means for detecting the rotation state of a wind turbine, a load means connected to a generator and consuming electric power, an electric current detecting means for detecting an electric current outputted from the generator, a selecting switch arranged in series in the load means and capable of switching the connecting state of electrically connecting the load means to the generator and the releasing state of releasing the load means from the generator and a control means for controlling the braking operation of the wind turbine by operating the selecting switch based on a detecting result of the rotation state detecting means and the electric current detecting means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wind power generator braking device that stops a wind power generator in a strong wind or the like, and more particularly to a wind power generator braking device that stops a wind turbine by electromagnetic force.

  In recent years, in response to problems such as global warming, devices using wind power, which is renewable energy, have been developed. As an apparatus using this wind power, there is a wind power generator that converts wind power into electric power by combining a windmill and a generator, and converts the obtained power into a form suitable for the intended use.

  The wind power generator is provided with an electromagnetic braking device (electromagnetic brake) that stops the rotation of the windmill when the rotational speed of the windmill is excessively increased due to an excessive wind speed such as a storm. For example, Patent Document 1 discloses a wind turbine that includes a wind turbine that is rotationally driven by wind power, a rotor that includes a permanent magnet that is rotationally driven integrally with the wind turbine, and a generator that has an armature circuit disposed opposite to the rotor. An electrical brake device for a machine, provided with a short-circuit device connected to an armature circuit and functioning as a windmill brake, and the short-circuit device is selectively driven to short-circuit the armature circuit and stop the windmill An electromagnetic braking device for a permanent magnet type wind power generator characterized by maintaining the state is described.

JP 2002-339856 A

  The braking device detects the rotational speed of the generator, and when the detected rotational speed exceeds a certain value, the generator circuit is short-circuited, and the rotational load is increased by the regenerative current, thereby suppressing the rotation of the rotor of the windmill. , Stop. The regenerative current generated by the braking operation (braking operation) is converted into heat by the load at the time of short circuit and released. The released thermal energy is the sum of the rotational energy of the windmill when the brake is started and the wind energy generated until the windmill stops.

  Here, in the braking device, the condition for starting the braking operation of the windmill and the generator is determined based on whether the rotational speed of the windmill, the rotational state of the output voltage of the generator, etc. exceed a certain condition. However, since various factors influence, the rotation state and the wind speed are not proportional. For this reason, the rotational speed is low because the resistance to rotation is large, but strong winds are blowing, and the wind turbine is stopped, or the resistance to rotation is small, so that the wind turbine can be operated even if the rotational speed is high. is there. Therefore, for safety design, if it is determined whether to perform a braking operation based on the rotation speed and output voltage set in response to severe conditions, the windmill may be stopped unnecessarily.

  This invention is made | formed in view of the above, Comprising: It aims at providing the braking device for wind power generators which can perform a braking operation appropriately according to an environment.

  In order to solve the above-described problems and achieve the object, the present invention provides a power supply between a generator that converts rotational energy of a windmill into electric power and a converter that outputs electric power generated by the generator to another device. A braking device for a wind power generator provided, a rotation state detection means for detecting a rotation state of the windmill, a load means connected to the generator and consuming electric power, and a current output from the generator A current detecting means for detecting the load, a connection state in which the load means is electrically connected to the generator, and the load means is released from the generator. A selection switch that can switch between a release state and a control unit that operates the selection switch based on detection results of the rotation state detection unit and the current detection unit to control a braking operation of the windmill. And features.

  Thereby, braking operation can be determined based on a driving | running state, and braking operation can be performed appropriately according to an environment.

  The control means determines a threshold rotation state for starting the braking operation of the windmill based on a relationship between a detection result of the rotation state detection means and a detection result of the current detection means, and the rotation state detection means When it is determined that the detection result at is greater than or equal to the threshold rotation state, it is preferable to start the braking operation of the windmill.

  Thereby, the reference | standard of a brake start can be set according to a driving | running state, and it can suppress that it brakes even if it is a usable condition.

  Preferably, the control means detects the rotation state and the current for each unit time, and determines a threshold rotation state for starting the braking operation of the windmill.

  By performing detection at regular time intervals in this way, it is possible to accurately control the braking operation while suppressing the load of calculation amount on the control means.

  The control means stores at least two kinds of relationships between the time since the start of the braking operation and the target rotation state, and the control means is detected by the current detection means at the start of the braking operation. A relationship between the time since the start of the braking operation and the target rotation state is selected based on the determined current, and the target rotation state calculated from the selected relationship and the rotation state of the detection result of the rotation state detection means, , And based on the comparison result, the selection switch determines whether to enter the connection state or release state.

  Thereby, rotation of a windmill can be decelerated according to the preset conditions, and the rotation speed of a windmill can be reduced, suppressing the vibration which a windmill and noise generate | occur | produce in a windmill. In addition, the braking operation can be controlled more appropriately by selecting the conditions set according to the driving state.

  The rotation state detection means detects a voltage output from the generator as a control object of the rotation state, and the control means compares the detected voltage with the voltage value of the target rotation state. It is preferable to perform control.

  Thereby, the rotation state can be detected easily and accurately. In addition, it is possible to perform control according to the allowable conditions of the generator.

  Further, the control means detects the rotation state by the rotation state detection means for each unit time during a braking operation, and calculates the target rotation state calculated from the relationship and the rotation state of the detection result of the rotation state detection means. Are preferably compared.

  By performing detection at regular time intervals in this way, it is possible to accurately control the rotation state while suppressing the load of calculation amount on the control means.

  In addition, when the rotation state of the detection result of the rotation state detection unit is equal to or greater than the target rotation state calculated from the relationship, the control unit sets the load unit to a connected state by the selection switch, and the rotation state When the rotation state of the detection result of the detection unit is lower than the target rotation state calculated from the relationship, it is preferable that the load unit is released by the selection switch.

  Thereby, rotation of a windmill can be decelerated along a target rotation state by simple control.

  The wind power generator braking apparatus according to the present invention has an effect that a braking operation can be appropriately performed according to the environment.

FIG. 1 is a schematic diagram showing a schematic configuration of an embodiment of a wind power generator having a wind power generator braking device of the present invention. FIG. 2 is a graph for explaining an example of a control operation by the control device. FIG. 3 is a flowchart for explaining the operation of the braking device according to the present embodiment. FIG. 4 is a flowchart for explaining the operation of the braking device according to the present embodiment. FIG. 5 is a graph illustrating an example of a control operation performed by the control device. FIG. 6A is a graph illustrating another example of the control operation performed by the control device. FIG. 6B is a graph illustrating another example of the control operation performed by the control device. FIG. 7 is a schematic diagram showing a schematic configuration of another embodiment of the wind power generator having the braking device for wind power generator of the present invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

(Embodiment)
FIG. 1 is a schematic diagram showing a schematic configuration of an embodiment of a wind power generator having a wind power generator braking device of the present invention. A wind power generator braking device (hereinafter referred to as a braking device if necessary) 10 is incorporated in the wind power generator 1. The wind power generator 1 includes a power generator 2, a windmill 3 attached to the input shaft of the power generator 2, and a braking device 10. When the windmill 3 receives wind, the windmill 3 rotates. The rotational force of the windmill 3 is input to the generator 2 via the input shaft 4 to drive it. Thereby, the generator 2 generates electrical energy. Thus, the generator 2 is an energy conversion device that converts wind power into electrical energy. The electric energy generated by the generator 2 is input to the converter 5 that is a power conversion device via the braking device 10. The converter 5 converts the electrical energy generated by the generator 2 and outputs it to a power consumption target 6 such as a home appliance.

  In the present embodiment, the braking device 10 is disposed between the generator 2 and the converter 5. The braking device 10 has input terminals Tia and Tib and output terminals Toa and Tob, and the output terminal of the generator 2 is connected to the input terminals Tia and Tib. Further, the input terminal of the converter 5 is connected to the output terminals Toa and Tob of the braking device 10. The braking device 10 stops the wind turbine 3 by short-circuiting the circuit of the generator 2 and stopping the generator 2 while increasing the rotational load of the generator 2 by regenerative power. Demonstrate the function. Next, the configuration of the braking device 10 will be described.

  The braking device 10 is a power consuming device 12 that is a power consuming device, a switching device 13 that is a switching device, a voltmeter 14 that is a voltage detecting device that detects a voltage output from the generator 2, and a control device. And a control device 15.

  The power consuming device 12 consumes electric energy supplied from the generator 2. An example of the power consuming device 12 is a resistor. The power consuming device 12 is connected in parallel to the circuit of the generator 2. In the example shown in FIG. 1, one terminal of the power consuming device 12 is electrically connected to the input terminal Tib of the braking device 10, and the other terminal is electrically connected to the input terminal Tia of the braking device 10 via the switching device 13. Connected to. The power consuming device 12 is not limited to a resistor as long as it can consume electric energy, and may be, for example, an electric motor, a lighting device, a magnetic generator, or the like.

  The switching device 13 electrically connects or disconnects the generator 2 and the power consuming device 12, and for example, a switch, a relay, a semiconductor switching element, or the like can be used. In the present embodiment, a switch is used as the switching device 13. When the switching device 13 electrically connects the generator 2 and the power consuming device 12, the generator 2 and the power consuming device 12 form a closed circuit.

  The voltmeter 14 detects a voltage (generator output voltage) output from the generator 2. Specifically, a potential difference between the input terminal Tia and the input terminal Tib is detected. The generator output voltage is substantially proportional to the rotational speed (rotational angular speed, rotational speed) of the generator 2. Further, the rotational speed of the generator 2 is proportional to the wind speed. The voltmeter 14 is electrically connected to the control device 15 and sends the detected generator output voltage to the control device 15.

  The ammeter 17 detects the current (output current) flowing between the input terminal Tia and the output terminal Toa in the present embodiment, which flows between the generator 2 and the converter 5. The ammeter 17 is electrically connected to the control device 15 and sends the detected output current to the control device 15.

  In the present embodiment, the control device 15 controls the operation of the switching device 13 based on the detection results of the voltmeter 14 and the ammeter 17. Specifically, the control device 15 electrically connects the generator 2 and the power consuming device 12 by closing the switching device 13, that is, by electrically connecting the switching device 13. Thereby, the supply destination of the electric energy generated by the generator 2 is the power consuming device 12. In addition, the control device 15 opens the switching device 13, that is, electrically cuts off the generator 2 and the power consuming device 12. Thereby, the supply destination of the electric energy generated by the generator 2 is the output terminals Toa and Tob of the braking device 10, more specifically, the converter 5. As described above, the control device 15 switches the switching device 13 to switch the supply destination of the electric energy generated by the generator 2 to one of the output terminals Toa and Tob of the power consumption device 12 or the braking device 10. .

  The control device 15 includes a so-called microcomputer that includes a processing unit 15P that performs arithmetic processing and a storage unit 15M that stores information necessary for the arithmetic processing. And the process part 15P reads the computer program for the brake control of the wind power generator 1 from the memory | storage part 15M, executes this, and brakes the wind power generator 1. FIG. In addition, the storage unit 15M stores a map and an expression showing a relationship between a voltage value serving as a reference for starting a braking operation (braking operation) and a current value, and a time after starting the braking operation and a target voltage value. A map, a formula and the like indicating the relationship are stored.

  In this embodiment, the braking device 10 stops the windmill 3 by braking the wind power generator 1 at the time of a strong wind. Specifically, the threshold value of the voltage is determined based on the voltage detected by the control device 15 of the braking device 10 with the voltmeter 14 and the detection result of the ammeter 17, and the voltage detected with the voltmeter 14 is higher than the threshold value. When the voltage is reached, the braking operation of the wind power generator 1 is started. The braking operation will be described in detail later. Thus, braking device 10 avoids over-rotation of wind turbine 3 and prevents electric power exceeding the allowable input of converter 5 from being input to converter 5.

  When the braking device 10 brakes the wind power generator 1, the control device 15 electrically connects the generator 2 and the power consuming device 12 by closing the switching device 13. As a result, the electric energy generated by the generator 2 is consumed by the power consuming device 12. As the electric energy generated by the generator 2 is consumed, the rotational load of the generator 2 increases. Further, as the rotational load increases, the wind turbine 3 decelerates and finally stops. Note that the electrical energy released when the windmill 3 stops is substantially equal to the sum of the rotational energy of the windmill 3 when braking is started and the wind energy generated until the windmill 3 stops. In the present embodiment, since a resistor is used for the power consuming device 12, the electric energy consumed by the power consuming device 12 is released as heat, for example, into the air (or liquid).

  Next, the operation of the braking device 10 will be described. The operation of the braking device 10 described next is also common in principle in the following modified examples and embodiments. FIG. 2 is a graph for explaining a control operation by the control device. In FIG. 2, the horizontal axis represents current and the vertical axis represents voltage.

  Here, in a state where electric power is output from the generator 2, the relationship between the current and voltage flowing between the generator 2 and the converter 5 varies depending on the operating state of the converter 5. Specifically, converter 5 changes the resistance in order to keep the rotation speed within a predetermined range. Therefore, the relationship between current and voltage changes according to the conditions of converter 5. FIG. 2 shows a straight line 100 having a slope a, a straight line 102 having a slope b, and a straight line 104 having a slope c as examples of the relationship between current and voltage. The inclination is a <b <c.

  In a state where the wind blown to the windmill 3 is strong (strong wind), the resistance of the converter 5 is set low, so that the slope of the straight line indicating the relationship between the current and the voltage becomes small, for example, the relationship shown by the straight line 100. Since the rotation speed (the number of rotations) and the voltage are proportional, the power generation amount at an arbitrary voltage can be increased by outputting with a small slope as shown by the straight line 100. As a result, the resistance of the generator 2 against the rotation of the windmill 3 can be increased, and even if a strong wind blows, the rotational speed is hardly increased, and the strong wind can prevent the rotational speed from increasing more than necessary. . On the other hand, if the wind blown to the windmill 3 continues in a normal (normal wind speed) or weak state, the resistance of the converter 5 is set high, so that the slope of the straight line indicating the relationship between current and voltage increases. , The relationship shown by the straight line 104 is obtained. Thereby, the resistance of the generator 2 with respect to rotation of the windmill 3 can be reduced, the windmill can be easily rotated, and a desired voltage can be output even with wind at a normal wind speed.

  Here, in order to determine whether or not a strong wind state exists from the relationship between the current and the voltage, the control device 15 has a relationship of the straight line 102 that is an inclination between the straight line 100 and the straight line 104 as a determination criterion relationship. Is remembered. In this way, by determining the power output condition based on the relationship of the straight line 102, it is possible to determine whether it is a strong wind state or a normal state, and a braking operation corresponding to the state can be performed. Note that the straight line 102 can be expressed as V = bI.

  Hereinafter, an example of control by the braking device 10 (determination by the control device 15) will be described with reference to FIG. FIG. 3 is a flowchart for explaining the operation of the braking device according to the present embodiment. First, during the period when the wind power generator 1 is operating, the control device 15 of the braking device 10 reads the current (Iin) and the voltage (Vin) as step S10. That is, the control device 15 acquires the current measurement result by the ammeter 17 and the voltage measurement result by the voltmeter 14. After reading the current (Iin) and the voltage (Vin) in step S10, the control device 15 determines in step S12 whether b × Iin <Vin. Here, b is the slope of the straight line 102 that is a criterion. That is, it is determined whether the detected voltage is larger than the voltage output from the determination reference when the current is the same. That is, in the graph of FIG. 2, it is determined whether the measurement result point is on the straight line 104 side with respect to the straight line 102.

If it is determined that b × Iin <Vin (Yes), that is, the point of the measurement result is on the straight line 104 side with respect to the straight line 102 in step S12, the control device 15 determines that the wind speed is normal, and step the threshold voltage is Vth = _{V 1} as S14. The threshold voltage is a reference voltage for determining whether or not to perform a braking operation. Thereafter, the control device 15 proceeds to step S18.

Further, the control device 15 does not satisfy b × Iin <Vin in step S12 (No), that is, b × Iin ≧ Vin, that is, the point of the measurement result is on the straight line 100 side or overlaps the straight line 102. After that a determination is made, is determined that the strong wind wind speed condition, the threshold voltage Vth = V ₂ as step S16. The threshold voltage _{V 2} is a voltage lower than the threshold voltage _{V 1.} Thereafter, the control device 15 proceeds to step S18.

  After determining the threshold voltage in step S14 or step S16, the control device 15 determines whether Vth <Vin as step S18. That is, it is determined whether the measured voltage (Vin) is higher than the set threshold voltage (Vth).

  If it is determined in step S18 that Vth <Vin (Yes), the control device 15 performs a brake process (braking operation) as step S20. In other words, the switching device 13 causes the power consuming device 12 and the generator 2 to be connected, the power output from the generator 2 is consumed by the power consuming device 12, and a load is applied to the generator 2 to generate power. The machine 2 and the windmill 3 are decelerated. The control apparatus 15 will complete | finish a process, if the generator 2 and the windmill 3 are stopped. If the control device 15 determines in step S18 that Vth <Vin is not satisfied (No), that is, if Vth ≧ Vin, the control device 15 ends the processing. Note that the control device 15 repeats the above process at regular time intervals. Moreover, if it determines with No by step S18, the control apparatus 15 may progress to step S10, and you may make it repeat the said process until it performs a brake process.

  As described above, by setting the threshold voltage based on the detection results of the current and voltage, it is possible to set the threshold according to the operation state. That is, a reference for starting the braking operation can be set according to the driving state. As a result, when the possibility of a strong wind state is high as in the above embodiment, the braking start voltage is lowered to start the braking even at a low rotational speed, and the possibility of a normal state is high. In this case, the braking start voltage can be increased, and the braking can be started when the rotational speed becomes high. As a result, when the windmill is receiving a large force and the wind is likely to change significantly, it is possible to start braking with sufficient conditions, the force applied to the windmill is appropriate, and the conditions may change When the normal wind speed is low, braking can be started under conditions that are close to a certain limit. As described above, since the braking start reference can be automatically set according to the operating state, the generator can be operated efficiently while maintaining high safety.

  Further, by detecting the operating state based on the relationship between the ammeter and the voltmeter, it is not necessary to detect the control condition from a converter or the like. Thereby, the apparatus configuration can be simplified. Moreover, when installing in the existing wind power generator, it becomes realizable only by replacing | exchanging a braking device. In addition, since it is not necessary to newly provide an output terminal in the converter or the like, an existing device can be used, and the device cost can be reduced.

  In addition, by setting the straight line 102 between the straight line 100 and the straight line 104 as a threshold value, it is possible to determine whether the control is performed in a normal wind speed state or in a strong wind state even if a certain measurement error occurs. Can do. Thereby, appropriate control can be performed without measuring with high accuracy. In the above embodiment, only the straight line 102 is used as the threshold value. However, a plurality of threshold values may be provided, and control may be switched according to each range.

  In the above embodiment, since the device configuration is simplified, the start condition of the braking operation is set to the case where the voltage value exceeds the threshold value, but the present invention is not limited to this. The condition for starting the braking operation may be set depending on the operating state.For example, when an anemometer is provided separately and the start of the braking operation is determined based on the measurement result of the anemometer, the threshold of the wind speed is determined according to the operating state. Can be changed. Further, the condition for starting the braking operation may be a case where a predetermined condition is satisfied a plurality of times, or a predetermined time is satisfied.

  Here, when braking the wind power generator 1, the braking device 10 preferably controls the switching device 13 based on the measurement result sent from the voltmeter 14. That is, it is preferable to switch between a state in which the generator 2 and the power consuming device 12 are electrically connected and a state in which the generator 2 and the power consuming device 12 are electrically disconnected. Note that the control of the switching device 13 based on the measurement result sent from the voltmeter 14 is performed using a preset relationship between the time from the start of control and the target voltage. It is preferable that the control device stores the relationship between the time from the start of a plurality of controls and the target voltage in the storage unit 15M, and selects the relationship to be used from the detection results of the current and voltage.

  Hereinafter, an example of the braking operation of the braking device 10 will be described. FIG. 4 is a flowchart for explaining the operation of the braking device according to the present embodiment. In the following, the state in which the switching device 13 is closed and the generator 2 and the power consuming device 12 are electrically connected is defined as the state in which the switching device 13 is ON, the switching device 13 is opened, and the generator 2 A state in which the power consuming device 12 is electrically disconnected is defined as a state in which the switching device 13 is OFF.

  First, if it determines with Yes at step 18 as mentioned above, the control apparatus 15 will start the braking of the wind power generator 1 as step S30. Note that, when braking is started, the control device 15 operates the switching device 13 to electrically connect the generator 2 and the power consuming device 12. That is, the switching device 13 is turned on. Note that the control device 15 may not turn on the switching device 13 at the start of braking, but may turn it on by processing to be described later.

  When braking is started in step S30, the control device 15 determines the relationship to be used, that is, the relationship between the time from the start of control used for the braking operation and the target voltage in step S36. Here, there are multiple relationships between the time from the start of control and the target voltage, and the relationship between the time from the start of control and the target voltage is the relationship between the current to be used and the voltage (the current that can be used). And voltage range). The control device 15 determines from the detection results of the current and voltage as a relationship using the relationship between the time from the start of control set for the condition including the detection result and the target voltage. The relationship to be used may be determined at the time of the determination in step S12 described above.

  After determining the relationship to be used in step S36, the control device 15 acquires again the generator output voltage Eg (similar to the voltage Vin described above) from the voltmeter 14 in step S38, and acquires the acquired generator output voltage Eg and the target. The voltage Et is compared. Specifically, it is determined whether Et ≦ Eg. The target voltage Et is a value calculated from the relationship determined to be used in step S36 and is a function of time from the start of braking. That is, the target voltage Et is a value that varies depending on the time from the start of braking. The target voltage Et is a value that gradually decreases with time.

  If the control device 15 determines in step S38 that Et ≦ Eg, that is, the generator output voltage Eg is equal to or higher than the target voltage Et (Yes), then in step S40, the control device 15 determines whether the switching device 13 is in the ON state. judge. If the control device 15 determines in step S40 that the switching device is ON (Yes), the control device 15 proceeds directly to step S48. If it is determined in step S40 that the switching device is not ON, that is, it is OFF (No), in step S42, after the switching device is turned on, the process proceeds to step S48. That is, if it is determined Yes in step S38, the switching device is turned on.

  If the control device 15 determines in step S38 that Et ≦ Eg is not satisfied, that is, Et> Eg and the generator output voltage Eg is smaller than the target voltage Et (No), as step S44, the switching device 13 is in the OFF state. It is determined whether it is. If the controller 15 determines in step S44 that the switching device 13 is OFF (Yes), the controller 15 proceeds directly to step S48. If it is determined in step S44 that the switching device 13 is not OFF, that is, it is ON (No), in step S46, the switching device 13 is turned off, and the process proceeds to step S48. That is, when it is determined No in step S38, the switching device 13 is turned off.

  Next, the control apparatus 15 determines whether the generator 2, ie, the windmill 3, is recognized as having stopped as step S48. In the present embodiment, whether or not the generator 2 is recognized as being stopped is determined by whether or not the generator output voltage Eg is equal to or lower than the stop threshold Eg0. The stop threshold value Eg0 is a value used to determine whether or not the generator 2 is recognized to have stopped.

  Here, when the rotational speed of the generator 2 decreases, the generator output voltage Eg also decreases, and when the generator 2 stops, the generator output voltage Eg becomes zero. Further, even if the generator 2 is not completely stopped, the generator 2 may be recognized as having stopped if the rotational speed is such that it is recognized as having been stopped. In the present embodiment, the stop threshold Eg0 is set to a value equal to or lower than the voltage output by the generator 2 when it is recognized that the generator 2 has stopped. Accordingly, the stop threshold Eg0 may be 0, that is, the generator output voltage Eg when the generator 2 is completely stopped.

  If it is determined in step S48 that the generator 2 is not stopped (No), that is, the voltage Eg is equal to or higher than the voltage Eg0, the control device 15 proceeds to step S38 and repeats the above processing. In addition, when determining in step S48 that the generator 2 is stopped (Yes), that is, the voltage Eg is less than the voltage Eg0, the control device 15 ends the process.

  As described above, in the braking operation of the braking device 10, the switching device 13 is repeatedly turned on and off. When the braking device 10 is in the on state, the electric energy generated by the generator 2 is consumed by the power consuming device 12, thereby generating the generator. The rotational speed of the generator 2, that is, the windmill 3 can be reduced by giving a rotational load to 2 and gradually reducing the voltage output from the generator 2. The windmill 3 can be substantially stopped by lowering the rotational speed of the windmill 3 so that it can finally be regarded as being stopped.

  Hereinafter, the braking operation using the relationship between the time from the start of control and the target voltage will be specifically described with reference to FIG. Here, FIG. 5 is a graph showing an example of the control operation by the control device. Here, in FIG. 5, three graphs are shown, and the top graph shows the relationship between voltage and time, and the middle graph shows ON / OFF of the switching device, that is, the switch state. The relationship between ON and OFF and time is shown, and the bottom graph shows the relationship between the acceleration (slope) of the target voltage and time. In addition, the horizontal axis of the three graphs is unified with the time axis. In the top graph, the vertical axis indicates voltage, and in the middle graph, the vertical axis indicates the switch state ON / OFF, and the bottom graph. Is the acceleration of the target voltage. On the time axis, the braking start is T = 0.

  First, as shown in FIG. 5, in this embodiment, since the acceleration of the target voltage, that is, the amount of change is constant, the target voltage decreases in proportion to time. The control device 15 switches the switch state between ON and OFF so that the voltage (output voltage) detected by the voltmeter 14 approaches the target voltage. Specifically, as shown in FIG. 5, the switch state is turned ON at T = 0, and thereafter, the output voltage becomes equal to or higher than the target voltage until T = t1, so the switch state is maintained ON. That is, in the operation shown in FIG. 4, “Yes” is continuously selected in step S38. Here, the output voltage detected at the timing of T = t1 is lower than the target voltage. Thereby, in the operation shown in FIG. 4, No is selected in step S38, and No is selected in step S44. Thereby, the control apparatus 15 switches a switch state to OFF.

  After that, until T = t2, the output voltage becomes lower than the target voltage, so that the switch state is maintained OFF. Thereafter, since the output voltage becomes equal to or higher than the target voltage at T = t2, the switch state is switched to ON again. Thereafter, it is switched OFF again at T = t3, and switched ON again at T = t4. Thereafter, at T = t5, the output voltage becomes substantially 0, and the wind power generator 1 is stopped.

  By switching the switching device between ON and OFF as described above, the output voltage can be reduced along the target voltage, and the windmill can be decelerated based on a preset deceleration model. Thereby, it is possible to suppress the occurrence of sudden deceleration or sudden stop during braking operation, that is, deceleration of the windmill, and vibration of the windmill can be suppressed. Since the vibration of the windmill can be suppressed, noise can be reduced, and it can be suppressed that a large load is applied locally or temporarily. By suppressing such a large load, the apparatus can be used for a long time.

  In addition, by preparing a plurality of relationships between the time from the start of control and the target voltage, a braking operation can be performed according to each condition. For example, during strong winds, various noises are generated in the surroundings, and therefore, the relationship between the time from the start of control and the target voltage determined by increasing the allowable range for noise can be used. In addition, at the normal wind speed, the time until the end of braking can be made longer. Thus, a more appropriate braking operation can be performed by selecting the relationship between the time from the start of control and the target voltage according to the conditions.

  Here, in the example shown in FIG. 5, the target voltage is decelerated at a constant acceleration. However, the present invention is not limited to this, and various patterns of target voltages can be set according to the device configuration and specifications. . Hereinafter, the pattern of the target voltage will be described with reference to FIGS. 6-1 and 6-2. Here, FIGS. 6A and 6B are graphs showing other examples of the control operation by the control device. In addition, FIGS. 6-1 and 6-2 show two graphs, respectively. The upper graph is a graph showing the relationship between the target voltage and time, and the lower graph is a graph showing the relationship between the acceleration (slope) of the target voltage and time. The horizontal axes of the two graphs are unified on the time axis. In the upper graph, the vertical axis represents the target voltage, and the lower graph represents the acceleration of the target voltage. On the time axis, the braking start is T = 0. Further, any pattern can be processed by the control method of FIG. 4 described above.

  The target voltage pattern shown in FIG. 6A is a monotonically increasing acceleration pattern in which the acceleration (slope) of the target voltage increases at a constant rate. As the acceleration gradually increases, the amount of change in the target voltage is small at the start of braking, and the amount of change in the target voltage is large immediately before the end of braking (immediately before stopping).

  In this way, by controlling the braking operation based on a pattern in which the amount of change in the target voltage at the start of braking is reduced, it is possible to prevent a large force from acting on the wind turbine rotating at high speed immediately after the start of braking. can do. That is, it is possible to suppress the braking for a long time with respect to the windmill rotating at high speed. As a result, the wind turbine can be slowly decelerated, and it is possible to suppress the occurrence of noise or a large load immediately after the start of braking.

  In the target voltage pattern shown in FIG. 6B, the acceleration (slope) of the target voltage increases at a constant rate, and after a certain period of time, the acceleration (slope) of the target voltage decreases at a constant rate. It is an acceleration pattern that combines monotonic deceleration. Thus, the acceleration gradually increases, so that the amount of change in the target voltage is small at the start of braking. In addition, in the present embodiment, when the target voltage becomes half of the initial voltage (braking start threshold voltage) after a certain period of time, the acceleration is gradually reduced so that the target voltage is also immediately before the end of braking (immediately before stopping). The amount of change becomes smaller.

  In this way, the braking operation is controlled based on the pattern in which the amount of change in the target voltage at the start of braking is reduced and the amount of change in the target voltage is also reduced immediately before the end of braking (immediately before stopping). Applying a large force to the wind turbine rotating at high speed can be suppressed. That is, it is possible to suppress the braking for a long time with respect to the windmill rotating at high speed. Furthermore, by reducing the amount of change in the target voltage just before stopping, the wind turbine can be gradually decelerated even when the return deceleration of the windmill is completed. That is, it is possible to suppress a sudden stop of the windmill. As a result, it is possible to gently start deceleration and end deceleration gradually with respect to the windmill, and it is possible to more appropriately suppress the generation of noise or a large load during the braking operation. .

  The target voltage pattern is not limited to the above three patterns. Note that the pattern in which the acceleration (slope) of the target voltage shown in FIG. 5 is constant has an advantage that the control device can be configured simply because the control is simple.

  Further, it is preferable to switch the operation pattern of the braking operation according to each condition. For example, the pattern shown in FIG. 6A is used when the wind is strong, and the pattern shown in FIG. 6B is used when the wind speed is normal. Thereby, the braking operation according to the situation can be performed more appropriately.

  Here, in the above embodiment, the voltage output from the generator is measured with a voltmeter and the control is performed based on the voltage. However, the present invention is not limited to this, and can detect the rotation speed of the windmill. I just need it. In addition, since the conversion from the rotational speed to the voltage can be processed by calculation, the operating state can be estimated by the relationship between the rotational speed and the current as in the above embodiment. Hereinafter, another example of the braking device will be described with reference to FIG. Here, FIG. 7 is a schematic diagram showing a schematic configuration of another embodiment of the wind power generator having the braking device for wind power generator of the present invention. The braking device 10a of the wind power generator 1a shown in FIG. 7 is the same as the braking device 10 of the wind power generator 1 described above except that a tachometer 16 is provided instead of the voltmeter 14. It is. Below, the point peculiar to brake device 10a is explained.

  The tachometer 16 detects the number of rotations of the wind turbine 3 of the wind power generator 1a (that is, the rotational speed of the generator 2 and the wind turbine 3). The tachometer 16 sends the detected number of rotations of the windmill 3 to the control device 15. In addition, when using a rotation speed for a measurement result like this embodiment, what is necessary is just to use a target rotation speed instead of the target voltage mentioned above. In addition, since the rotation speed of the windmill 3 and the voltage output from the generator 2 are in a substantially proportional relationship, the same control can be performed using any value. Although the amount of calculation increases, a voltage may be calculated from the number of rotations using a proportional relationship and compared with the target voltage.

  As described above, the same control can be performed even if a tachometer is provided instead of the voltmeter and the rotation speed of the windmill is calculated. In addition, since the apparatus can be simplified and the apparatus cost is reduced, the above-described rotation speed and output voltage are preferably measured, but the present invention is not limited thereto. Any measuring object that can linearly detect the driving state of the windmill or generator may be used. By controlling the ON / OFF of the brake based on the detection result, the pattern is set in advance as described above. Based on this, the windmill can be braked.

  Moreover, in the said embodiment, although the target value in each time was made into one value, this invention is not limited to this. For example, the target value may have a certain width. Also, the threshold value for switching the switching device from ON to OFF and the threshold value for switching the switching device from OFF to ON may be different.

  In the above embodiment, since the device configuration is simplified, the detection value used as the reference for ON / OFF control of the switching device and the detection value used as the reference for determination of braking start are detected by the same measuring device. However, the present invention is not limited to this. For example, the determination of the start of braking may be performed by using an anemometer and starting the braking when the wind speed exceeds a certain speed.

  Further, since the braking operation can be performed more appropriately, the above-described setting of the braking start condition according to the driving state (the process of FIG. 3) and the setting of the braking pattern according to the driving state (the process of FIG. 4). ) Is preferably performed, but only one of the treatments may be performed. Even if only one of the processes is performed, the effects of the above-described processes can be obtained.

  As described above, the braking device for wind power generator according to the present invention is useful for use as a braking device when the wind power generator is stopped, and is particularly suitable for a braking device for small wind power generation of 10 kW or less.

DESCRIPTION OF SYMBOLS 1, 1a Wind generator 2 Generator 3 Windmill 4 Input shaft 5 Converter 6 Power consumption object 10, 10a Brake device (brake device for wind generator)
DESCRIPTION OF SYMBOLS 12 Electric power consumption apparatus 13 Switching apparatus 14 Voltmeter 15M Memory | storage part 15P Processing part 15 Control apparatus 16 Tachometer 17 Ammeter

Claims (7)

A braking device for a wind generator provided between a generator that converts rotational energy of a windmill into electric power and a converter that outputs electric power generated by the generator to another device,
Rotation state detection means for detecting the rotation state of the windmill;
A load means connected to the generator and consuming electric power;
Current detection means for detecting a current output from the generator;
Selection that is arranged in series with the load means and that can switch between a connected state in which the load means is electrically connected to the generator and a released state in which the load means is released from the generator A switch,
A braking device for a wind power generator, comprising: a control unit that operates the selection switch based on detection results of the rotation state detection unit and the current detection unit to control a braking operation of the windmill. The control means determines a threshold rotation state for starting the braking operation of the windmill based on the relationship between the detection result of the rotation state detection means and the detection result of the current detection means,
The braking device for a wind power generator according to claim 1, wherein when the detection result by the rotation state detection means is determined to be equal to or greater than a threshold rotation state, a braking operation of the windmill is started.   The wind power generator braking according to claim 2, wherein the control means detects the rotation state and the current every unit time, and determines a threshold rotation state for starting a braking operation of the windmill. apparatus. The control means stores at least two kinds of relationships between the time since the start of the braking operation and the target rotation state,
The control means selects a relationship between the time after starting the braking operation and the target rotation state based on the current detected by the current detecting means at the start of the braking operation,
The target rotation state calculated from the selected relationship is compared with the rotation state detected by the rotation state detection means, and based on the comparison result, the selection switch determines whether the connection state or the release state is set. The braking device for a wind power generator according to any one of claims 1 to 3, wherein: The rotation state detection means detects a voltage output from the generator as a control object of the rotation state,
The braking device for a wind power generator according to claim 4, wherein the control means performs control by comparing the detected voltage with a value of the voltage in the target rotation state.   The control unit detects a rotation state by the rotation state detection unit for each unit time during a braking operation, and compares the target rotation state calculated from the relationship with the rotation state of the detection result of the rotation state detection unit. The braking device for wind power generators according to claim 4 or 5, wherein   When the rotation state of the detection result of the rotation state detection unit is equal to or greater than the target rotation state calculated from the relationship, the control unit causes the load unit to be connected by the selection switch, and the rotation state detection unit 7. The load unit is released by the selection switch when the rotation state of the detection result is lower than the target rotation state calculated from the relationship. 8. The braking device for wind generators as described.

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