JP2012165584A - Wind power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily implement control which maintains high output against change of wind speed in a wind power generation device.SOLUTION: A converter control part comprises a duty ratio indication part indicating a duty ratio, and a variation determination part selecting positive first variation or negative second variation as variation in a duty ratio indication value from a duty ratio indication value corresponding to immediately previous sampling. When the absolute value of the first variation is smaller than that of the second variation; the variation determination part selects variation having the same sign as a reference sign that is a positive or negative sign of the variation in the duty ratio indication value corresponding to the immediately previous sampling, from the first variation and second variation in the case that output power is equal to or larger than reference power being output power obtained in the immediately previous sampling, and selects variation having the different sign from the reference sign in the case that the output power is smaller than the reference power.

Description

  The present invention relates to a wind turbine generator.

  Conventionally, in a wind turbine generator, various controls are performed so that the output power becomes maximum. For example, in the wind power generation facility described in Japanese Patent Application Laid-Open No. 2006-149055, characteristic data indicating the correlation between the output power of the voltage conversion device 3 when the maximum power is extracted and the output voltage of the wind power generator 2 is Pre-stored in the control circuit 8. The characteristic data shows the output power of the voltage converter 3 on the curve connecting the maximum power points and the output voltage of the wind power generator 2 in a stepwise manner (paragraph 0018). In the wind power generation facility, the output voltage of the wind power generator 2 and the output power of the voltage conversion device 3 are measured. Then, a droop current value for calculating the output voltage of the wind power generator 2 and the output power of the voltage converter 3 to be close to a curve connecting the maximum power points in the characteristic data is calculated and notified to the voltage converter 3. (Paragraphs 0019 and 0020).

  In the wind turbine generator described in Japanese Patent Laid-Open No. 2003-120504, the wind speed is detected by the wind speed detector 21. Then, the rotational speed command calculator 22 determines the rotational speed of the windmill 1 that can receive wind energy most efficiently based on the detected value of the wind speed. The obtained rotation speed is output as a rotation speed command to the rotation speed controller 12, and the windmill 1 is operated based on the rotation speed command (paragraph 0018).

  In the wind turbine generator described in Japanese Patent Laid-Open No. 2003-134890, the generator speed estimator 10 uses the synchronous generator 2 based on the voltage and current signals of the two-axis components output from the three-phase / two-phase converter 9. Is estimated (paragraph 0010). As a result, the synchronous generator connected to the wind turbine is driven at a variable speed without using the generator speed sensor (paragraph 0007).

On the other hand, Japanese Patent Application Laid-Open No. 57-206929 relates to a maximum output power control method for a photovoltaic cell. In the DC-AC conversion system using the photovoltaic cell 1 of FIG. 4 as a power source and using the separately excited converter 2, the output of the photovoltaic cell 1 is changed when the voltage setting value of the separately excited converter 2 is changed in the increasing or decreasing direction. When the power increases, control for changing the voltage setting value in the same direction is further performed. When the output power of the photovoltaic cell 1 decreases, control is performed to change the voltage setting value in the reverse direction (page 4, upper left column 12 line to upper right column 9 line).
JP 2006-149055 A JP 2003-120504 A JP 2003-134890 A JP-A-57-206929

  By the way, in the control method described in Japanese Patent Application Laid-Open No. 2006-149055, it is necessary to acquire the characteristic data of the wind power generation facility in advance and store it in the control circuit 8. For this reason, if the specification of a windmill or a wind power generator is changed, characteristic data must be acquired again. In addition, characteristic data specific to each facility must be acquired for each of the plurality of wind power generation facilities. Therefore, it is difficult to perform highly versatile control.

  In the control method described in Japanese Patent Laid-Open No. 2003-120504, since it is necessary to continuously acquire the rotation speed of the windmill, the structure of the wind turbine generator may be complicated and the manufacturing cost of the device may increase. Further, in the control method described in Japanese Patent Application Laid-Open No. 2003-134890, since the speed of the synchronous generator 2 is estimated based on the characteristics of the synchronous generator 2, the specification of the synchronous generator 2 is changed. The characteristic data must be reacquired, and it is difficult to perform highly versatile control.

  This invention is made | formed in view of the said subject, and aims at implement | achieving easily the control which maintains a high output with respect to a wind speed change in a wind power generator.

  A wind turbine generator according to an exemplary aspect of the present invention includes a windmill, a generator having a rotating unit connected to the windmill, and AC-DC that converts AC power output from the generator into DC power. A converter, a DC-DC converter that converts a voltage of DC power output from the AC-DC converter, and an output current and output voltage from the DC-DC converter are sampled and output at a sampling period. A power detection unit for obtaining power; and a converter control unit for controlling a duty ratio of the DC-DC converter based on the output power, wherein the converter control unit outputs the output obtained at the previous sampling time. A power storage unit that stores power as reference power, a duty ratio instruction unit that indicates the duty ratio to the DC-DC converter, and a duty ratio instruction that corresponds to the previous sampling An instruction value storage unit that stores the reference instruction value, and a change amount determination unit that selects a positive first change amount or a negative second change amount as a change amount of the duty ratio instruction value from the reference instruction value; A sign storage unit that stores, as a reference sign, a sign of a change amount of the duty ratio instruction value corresponding to the previous sampling, wherein the absolute value of the first change amount is an absolute value of the second change amount If the output power obtained by the power detection unit is equal to or greater than the reference power in the change amount determination unit, the reference number is calculated from the first change amount and the second change amount. Is selected, and the output power obtained by the power detection unit is smaller than the reference power, the first change amount and the second change amount are different from the reference code. Change of sign There is selected.

  In the present invention, it is possible to easily realize control for maintaining a high output against a change in wind speed.

Drawing 1 is a figure showing the whole wind power generator composition concerning one embodiment. FIG. 2 is a cross-sectional view of the generator. FIG. 3 is a plan view of the stator and the rotor. FIG. 4 is a diagram illustrating a flow of one control cycle of the DC-DC converter. FIG. 5 is a diagram showing the relationship between the rotational speed of the windmill and the output power from the DC-DC converter.

  FIG. 1 is a diagram showing an overall configuration of a wind turbine generator 1 according to an embodiment of the present invention. The wind turbine generator 1 includes a windmill 2, a generator 3, an AC-DC converter 41, a DC-DC converter 42, a power detection unit 43, a converter control unit 5, a storage battery 6, and a converter. A stop unit 71 and an overcurrent protection unit 72 are included. A rotating unit 32 (see FIG. 2), which will be described later, of the generator 3 is connected to the rotating shaft 21 of the windmill 2.

  In the wind power generator 1, the rotating part 32 of the generator 3 rotates as the windmill 2 receives the wind and rotates. Thereby, the kinetic energy generated by the windmill 2 is converted into electric energy by the generator 3. In the generator 3, AC power having a variable frequency corresponding to the rotational speed of the windmill 2 is generated. The AC power output from the generator 3 is guided to the AC-DC converter 41 and converted into DC power by the AC-DC converter 41. As the AC-DC converter 41, for example, a diode bridge is used. The DC power voltage output from the AC-DC converter 41 is converted into a predetermined voltage by the DC-DC converter 42. The storage battery 6 is connected to the DC-DC converter 42 and is charged by the output current from the DC-DC converter 42.

  The power detector 43 samples the output current and output voltage from the DC-DC converter 42 at a predetermined sampling period, and obtains the output power from the DC-DC converter 42. When the output voltage acquired by the power detection unit 43 is larger than the maximum voltage of the storage battery 6 or smaller than the lowest voltage of the storage battery 6, the converter stop unit 71 is connected to the DC-DC converter 42. Stop operation. The converter stop unit 71 has a function of determining the rated voltage of the storage battery 6 based on the output voltage and setting the maximum voltage and the minimum voltage of the storage battery 6. When the output current acquired by the power detection unit 43 is larger than the rated current at the time of charging the storage battery 6, the overcurrent protection unit 72 applies to the DC-DC converter 42 from the duty ratio instruction unit 52 described later. The duty ratio instruction value is decreased by a predetermined amount. The change of the duty ratio instruction value by the overcurrent protection unit 72 has priority over the duty ratio instruction by the duty ratio instruction unit 52.

  The converter control unit 5 controls the DC-DC converter 42 by the PMW (Pulse Width Modulation) method. Specifically, the duty ratio of the DC-DC converter 42 is continuously controlled based on the output power from the DC-DC converter 42. In the following description, the power detection unit 43 obtains output power from the DC-DC converter 42, and the converter control unit 5 “controls” a cycle in which the duty ratio is instructed to the DC-DC converter 42. Cycle. Of the control cycles performed before the currently executed control cycle, the latest control cycle is referred to as a “previous control cycle”. Furthermore, sampling that is the acquisition of the output current and output voltage performed in the previous control cycle is referred to as “previous sampling”.

  FIG. 2 is a cross-sectional view of the generator 3. In the following description of the generator 3, the upper side of the generator 3 in the direction of the central axis J1 is simply referred to as “upper side” and the lower side is simply referred to as “lower side”. The vertical direction does not indicate the vertical direction when the generator 3 is incorporated in the wind power generator 1. Further, the circumferential direction around the central axis J1 is simply referred to as “circumferential direction”, and the radial direction around the central axis J1 is simply referred to as “radial direction”.

  The generator 3 is an inner rotor type. The generator 3 includes a stationary part 31, a rotating part 32, and a bearing mechanism 33. The bearing mechanism 33 supports the rotating part 32 so as to be rotatable with respect to the stationary part 31 around the central axis J1 of the generator 3.

  The stationary part 31 includes a housing 311, a stator 312, and a bracket 313. The housing 311 has a bottomed substantially cylindrical shape. The stator 312 has a substantially cylindrical shape centered on the central axis J <b> 1 and is attached to the inner surface of the housing 311. The bracket 313 is substantially annular and is attached to the upper end of the housing 311. Stator 312 includes a stator core 314, an insulator 315, and a coil 316. The stator core 314 is formed by laminating thin plate-shaped magnetic steel plates. The insulator 315 is an insulator that covers the surface of the stator core 314.

  The rotating part 32 is a so-called rotor. Hereinafter, the rotating unit 32 is referred to as a “rotor 32”. The rotor 32 is substantially cylindrical. The rotor 32 is supported inside the stator 312 so as to be rotatable about the central axis J1. The rotor 32 includes a shaft 321, a rotor main body 322, and a rotor magnet 323. The shaft 321 is disposed around the central axis J1. The rotor body 322 has a substantially cylindrical shape and is fixed to the shaft 321. The rotor main body 322 is formed by laminating thin magnetic steel plates. The rotor magnet 323 is disposed in the rotor main body 322.

  The bearing mechanism 33 includes an upper ball bearing 331 and a lower ball bearing 332. The upper ball bearing 331 is attached to the inner peripheral surface of the bracket 313. The lower ball bearing 332 is attached to the center of the bottom of the housing 311. The shaft 321 protrudes above the bracket 313 through the opening of the bracket 313. The shaft 321 is supported by the upper ball bearing 331 and the lower ball bearing 332 so as to be rotatable about the central axis J1. The shaft 321 is connected to the rotating shaft 21 of the windmill 2 shown in FIG.

  FIG. 3 is a plan view of the stator 312 and the rotor 32. Illustration of the insulator 315 is omitted. Stator core 314 includes twelve teeth 317 and a core back 318. Each layer of the laminated steel plates constituting the stator core 314 is a single metal plate that is continuous in the circumferential direction. The core back 318 is annular. The teeth 317 protrude from the core back 318 toward the central axis J1, that is, toward the rotor 32. The teeth 317 are arranged at an equal pitch in the circumferential direction. A coil 316 is formed by winding a conductive wire on each tooth 317 via an insulator 315 shown in FIG. The coil 316 is formed by concentrated winding, and one coil 316 is formed on one tooth 317.

  The rotor body 322 has ten holes 324 formed in parallel to the central axis J1. The holes 324 are arranged at an approximately equal pitch in the circumferential direction. Ten rotor magnets 323 are inserted and held in the ten holes 324, respectively. Actually, the rotor magnet 323 is provided on the upper surface and the lower surface of the rotor body 322. As the rotor 32 rotates relative to the stator 312, electric power is extracted from the stator 312. As shown in FIG. 1, the U-phase, V-phase, and W-phase output lines 34 are drawn from the stator 312 of the generator 3 and connected to the AC-DC converter 41. The current from the generator 3 is guided to the AC-DC converter 41 via the three output lines 34 as described above.

  Converter control unit 5 includes a power storage unit 51, a duty ratio instruction unit 52, an instruction value storage unit 53, a change amount determination unit 54, and a code storage unit 55. The power storage unit 51 stores the output power from the DC-DC converter 42 obtained by the power detection unit 43 during the previous sampling as reference power. The duty ratio instruction unit 52 instructs the DC-DC converter 42 on the duty ratio. The instruction value storage unit 53 stores the duty ratio instruction value instructed to the DC-DC converter 42 by the duty ratio instruction unit 52 in the previous control cycle as a reference instruction value. That is, the reference instruction value is a duty ratio instruction value corresponding to the previous sampling.

  The change amount determination unit 54 determines how much the duty ratio instruction value is changed from the reference instruction value in the currently executed control cycle. The change amount determination unit 54 includes a first comparator 541 and a second comparator 542. The code storage unit 55 refers to the change amount of the duty ratio instruction value determined by the change amount determination unit 54 in the previous control cycle, that is, the positive or negative sign of the change amount of the duty ratio instruction value corresponding to the previous sampling. Store as code. In the present embodiment, when the reference code is positive, “+1” is stored in the code storage unit 55 as a numerical value indicating the reference code. When the reference code is negative, “−1” is stored in the code storage unit 55. . For example, a memory is used as the power storage unit 51, the instruction value storage unit 53, and the code storage unit 55.

  Next, the control flow of the DC-DC converter 42 in the wind power generator 1 will be described. Hereinafter, one control cycle will be described on the assumption that the control of the DC-DC converter 42 has already been continuously performed. Therefore, the power storage unit 51, the instruction value storage unit 53, and the code storage unit 55 store the reference power, the reference instruction value, and the reference code related to the previous sampling, respectively. FIG. 4 is a diagram illustrating a flow of one control cycle of the DC-DC converter 42.

  In the control of the DC-DC converter 42, first, the power detection unit 43 samples the output current and output voltage from the DC-DC converter 42 (step S11). Subsequently, output power is obtained from the output current and output voltage of the DC-DC converter 42 (step S12). The output power of the DC-DC converter 42 is sent to the first comparator 541 of the change amount determination unit 54. In the first comparator 541, the output power of the DC-DC converter 42 is compared with the reference power stored in the power storage unit 51 (step S13). When the output power is greater than or equal to the reference power, “+1” is output from the first comparator 541 (step S14), and when the output power is smaller than the reference power, “−1” is output from the first comparator 541. Is output (step S15). In the above description, “when it is greater than or equal to the reference power” and “when it is smaller than the reference power” is substantially the same even if it is replaced with “when it is greater than the reference power” and “when it is less than or equal to the reference power”. is there. The same applies to other comparison operations in the following description. The output power of the DC-DC converter 42 obtained by the power detection unit 43 is also sent to the power storage unit 51 and stored as reference power used in the next control cycle.

  In the change amount determining unit 54, “+1” or “−1” that is a numerical value output from the first comparator 541 and “+1” or “−1” that is a numerical value indicating a reference code stored in the code storage unit 55. -1 "is input to the second comparator 542 (step S16). When “+1” is output from the first comparator 541 and the numerical value indicating the reference sign is “+1”, “+1” is input to the second comparator 542. When “+1” is output from the first comparator 541 and the numerical value indicating the reference sign is “−1”, “−1” is input to the second comparator 542. When “−1” is output from the first comparator 541 and the numerical value indicating the reference sign is “+1”, “−1” is input to the second comparator 542. When “−1” is output from the first comparator 541 and the numerical value indicating the reference sign is “−1”, “+1” is input to the second comparator 542.

  In the second comparator 542, the numerical value input from the first comparator 541 is compared with “0” (step S17). When the numerical value input from the first comparator 541 is “+1”, that is, when it is equal to or greater than 0, the change amount of the duty ratio instruction value is positive from the second comparator 542 to the duty ratio instruction unit 52. The first variation “+ N” that is the value of is output (step S18). Further, when the numerical value input from the first comparator 541 is “−1”, that is, smaller than 0, the amount of change in the duty ratio instruction value from the second comparator 542 to the duty ratio instruction unit 52. As a result, the second variation “−M”, which is a negative value, is output (step S19).

  In other words, in the change amount determination unit 54, when the output power of the DC-DC converter 42 obtained by the power detection unit 43 is equal to or greater than the reference power, the first change amount “+ N” and the second change amount When the change amount of the code equal to the reference code is selected from “−M” and the output power of the DC-DC converter 42 is smaller than the reference power, the first change amount “+ N” and the second change amount “− From “M”, the change amount of the code different from the reference code is selected. The absolute value “N” of the first change amount is smaller than the absolute value “M” of the second change amount. The change amount of the duty ratio instruction value output from the second comparator 542 is also sent to the code storage unit 55, and the sign of the change amount is stored as a reference code used in the next control cycle.

  In the duty ratio instruction unit 52, the duty ratio instruction value is obtained by adding the change amount input from the second comparator 542 to the reference instruction value stored in the instruction value storage unit 53 (step S20). The duty ratio instruction value is output from the duty ratio instruction unit 52 to the DC-DC converter 42. The duty ratio of the DC-DC converter 42 is changed to be equal to the duty ratio instruction value (step S21). The duty ratio instruction value output from the duty ratio instruction unit 52 is also sent to the instruction value storage unit 53 and stored as a reference instruction value used in the next control cycle. In the wind turbine generator 1, the control cycle shown in steps S11 to S21 is repeated. The time from when the duty ratio is changed in one control cycle until the duty ratio is changed in the next control cycle, that is, the duty ratio update period is based on the time constant of the blade of the wind turbine 2 or the like. The duty ratio is set large enough to be reflected in the rotational speed of the windmill 2 and small enough to follow the change in the wind speed. As the time constant, for example, a mechanical time constant defined based on inertia between the windmill 2 and the rotor 32 is used.

  FIG. 5 is a diagram showing the relationship between the rotational speed of the windmill 2 and the output power from the DC-DC converter 42. A broken line 81 in FIG. 5 indicates the relationship between the rotational speed of the windmill 2 and the output power from the DC-DC converter 42 when the wind speed is constant at 3 m / s. Dashed lines 82 to 86 indicate the relationship between the rotational speed of the windmill 2 and the output power from the DC-DC converter 42 when the wind speed is constant at 4 m, 5 m, 6 m, 7 m, and 8 m per second. Broken lines 81 to 86 are obtained by a wind tunnel experiment. When the broken lines 81 to 86 are obtained, the DC-DC converter 42 is not controlled by the converter control unit 5.

  A square mark 91 in FIG. 5 indicates the rotational speed of the windmill 2 and the DC-DC when the wind speed is randomly changed in a state where the above-described control is performed on the DC-DC converter 42 by the converter controller 5. The relationship with the output electric power from the converter 42 is shown. A solid line 92 indicates the rotational speed of the windmill and the DC-DC conversion when the absolute value of the first change amount is equal to the absolute value of the second change amount in the control of the DC-DC converter by the converter control unit. The relationship with the output power from the container is shown. Hereinafter, the control corresponding to the solid line 92 is referred to as “control of comparative example”. A square mark 91 and a solid line 92 are obtained by simulation.

  In the wind turbine generator 1, as indicated by broken lines 81 to 86 in FIG. 5, there is a rotation speed of the windmill 2 at which the output power is the highest at each wind speed. A two-dot chain line 87 is a line that approximately connects the peaks of the broken lines 81 to 86. In the wind power generator 1, it can be said that the closer the relationship between the rotational speed of the windmill 2 and the output power from the DC-DC converter 42 is to the two-dot chain line 87, the better the followability to the wind speed change and the higher the power generation efficiency.

  By the way, in the wind power generator in which the output control of the DC-DC converter is not performed, when the wind speed rapidly decreases, the output from the DC-DC converter plays a role of a brake, and the rotational speed of the windmill rapidly decreases. To do. After that, even if the wind speed increases, it takes a certain amount of time to increase the rotational speed of the once reduced windmill. Therefore, the rotational speed of the windmill does not easily return to the rotational speed suitable for the wind speed, and the power generation efficiency decreases. End up.

  Further, even when the duty ratio of the DC-DC converter is controlled, when the absolute value of the first change amount is made equal to the absolute value of the second change amount as in the control of the comparative example, If the second change amount is set so that the duty ratio can be greatly reduced following the rapid decrease in the wind speed, the first change amount becomes too large, and the variation of the duty ratio with respect to the wind speed change becomes excessive. That is, stable control of the DC-DC converter 42 becomes difficult. On the other hand, if the first change amount is set so small that the duty ratio can be stably controlled, the absolute value of the second change amount also becomes small, so that it is difficult to greatly reduce the duty ratio following a rapid decrease in the wind speed. It becomes. As a result, the rotational speed of the windmill is drastically reduced and the power generation efficiency is lowered. That is, as shown in FIG. 5, the relationship between the rotational speed of the windmill and the output power from the DC-DC converter is separated from the two-dot chain line 87.

  In the change amount determination unit 54 of the wind turbine generator 1 according to this embodiment, as described above, when the output power of the DC-DC converter 42 obtained by the power detection unit 43 is equal to or higher than the reference power, When a change amount having a sign equal to the reference sign is selected from the one change amount “+ N” and the second change amount “−M” and the output power of the DC-DC converter 42 is smaller than the reference power, the first change From the amount “+ N” and the second change amount “−M”, a change amount of a sign different from the reference sign is selected. The absolute value “N” of the first change amount is smaller than the absolute value “M” of the second change amount. For this reason, even if it is a case where a wind speed falls rapidly, it can prevent that the rotation speed of the windmill 2 falls rapidly by reducing a duty ratio largely. Even when the wind speed increases, the duty ratio is increased by increasing the duty ratio by the first change amount “+ N” having an absolute value smaller than the absolute value “M” of the second change amount in one control cycle. Control can be realized. As described above, in the wind turbine generator 1, it is possible to easily realize control that maintains a high output against changes in wind speed.

  Thus, since the wind power generator 1 can control the wind power generator 1 without acquiring data indicating the characteristics of the windmill 2 or the generator 3 in advance, the structure of the wind power generator 1 is various. The present invention can be easily applied to wind turbine generators having various types of windmills and generators. In other words, highly versatile control can be realized by applying the structure of the wind turbine generator 1. Moreover, since the wind power generator 1 can be controlled without acquiring the rotational speed and the wind speed of the windmill, the structure of the wind power generator 1 can be simplified. Thereby, the manufacturing cost of the wind power generator 1 can be reduced.

  In the wind power generator 1, when the output voltage acquired by the power detection unit 43 is larger than the maximum voltage of the storage battery 6 or smaller than the minimum voltage of the storage battery, the converter stop unit 71 performs DC− The operation of the DC converter 42 is stopped. Thereby, the overcharge of the storage battery 6 can be prevented. Further, when the output current acquired by the power detection unit 43 is larger than the rated current of the storage battery 6, the overcurrent protection unit 72 instructs the duty ratio to the DC-DC converter 42 from the duty ratio instruction unit 52. The value is reduced by a predetermined amount. Thereby, the burning of each structure by overcurrent etc. can be prevented.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  For example, the structure of the windmill 2 and the generator 3 is not limited to what was described in the said embodiment, You may change variously. The converter control unit 5 may be realized by an electronic circuit or mechanical hardware, or may be realized by software. When the converter control unit 5 is realized by hardware, for example, a circuit having a function of delaying a signal such as an integration circuit is used as the power storage unit 51, the instruction value storage unit 53, and the code storage unit 55. it can.

  The configurations in the above embodiment and each modification may be appropriately combined as long as they do not contradict each other.

  The present invention is applicable to a wind power generator.

DESCRIPTION OF SYMBOLS 1 Wind power generator 2 Windmill 3 Generator 5 Converter control part 6 Storage battery 32 Rotation part 41 AC-DC converter 42 DC-DC converter 43 Power detection part 51 Power storage part 52 Duty ratio instruction | indication part 53 Instruction value storage part 54 Change amount determination unit 55 Code storage unit 71 Converter stop unit 72 Overcurrent protection unit S11 to S21 Steps

Claims (3)

With a windmill,
A generator having a rotating part connected to the windmill;
An AC-DC converter that converts AC power output from the generator into DC power;
A DC-DC converter that converts a voltage of DC power output from the AC-DC converter;
A power detector that samples output current and output voltage from the DC-DC converter in a sampling period to obtain output power;
A converter control unit for controlling a duty ratio of the DC-DC converter based on the output power;
With
The converter controller is
A power storage unit that stores the output power obtained during the previous sampling as reference power;
A duty ratio indicating unit that indicates the duty ratio to the DC-DC converter;
An instruction value storage unit for storing a duty ratio instruction value corresponding to the previous sampling as a reference instruction value;
A change amount determination unit that selects a positive first change amount or a negative second change amount as a change amount of the duty ratio instruction value from the reference instruction value;
A code storage unit that stores, as a reference code, a sign of a change amount of the duty ratio instruction value corresponding to the previous sampling;
With
An absolute value of the first change amount is smaller than an absolute value of the second change amount;
In the change amount determination unit, when the output power obtained by the power detection unit is equal to or greater than the reference power, a change in code equal to the reference code from the first change amount and the second change amount When the amount is selected and the output power obtained by the power detection unit is smaller than the reference power, a change amount of a code different from the reference code is obtained from the first change amount and the second change amount. Selected wind power generator. A storage battery charged by an output current from the DC-DC converter;
A converter that stops the operation of the DC-DC converter when the output voltage acquired by the power detection unit is larger than the maximum voltage of the storage battery or smaller than the minimum voltage of the storage battery. A stop,
The wind turbine generator according to claim 1, further comprising: A storage battery charged by an output current from the DC-DC converter;
When the output current acquired by the power detection unit is larger than the rated current at the time of charging the storage battery, a duty ratio instruction value for the DC-DC converter from the duty ratio instruction unit is set to a predetermined value. An overcurrent protection unit that reduces the size,
The wind turbine generator according to claim 1, further comprising:

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