JP5703685B2 - Wind power generator and blade pitch angle control device thereof - Google Patents

Description

  In the present invention, a plurality of blades are attached to a hub at the tip of a power transmission shaft that is horizontally supported in a nacelle, and each pitch angle, which is an attachment angle of the blade, is independently changed corresponding to an azimuth angle. The present invention relates to a wind power generator and a blade pitch angle control device thereof.

As shown in FIG. 5, the basic configuration of the wind turbine generator is such that a nacelle 52 is horizontally attached to an upper end portion of a tower 51 standing on the ground, and a power transmission shaft 53 horizontally supported in the nacelle 52. plural hub 54 attached to the tip (usually three) are mounted at equal intervals blade B ₁ .about.B ₃ along the circumferential direction of the blade B ₁ .about.B ₃ of the plurality by wind energy The power transmission shaft 53 is rotated by continuously rotating, the speed of the power transmission shaft 53 is increased by a speed increaser 55, and the generator 56 is rotated to generate electric power. Its use continues to increase as a harmless power generator. In FIG. 5, reference numeral 57 denotes a brake device that forcibly stops the rotation of the blades B _{1 to} B _{3 in} a strong wind or a failure.

By the way, the wind energy is attenuated by friction with the ground surface at a portion close to the ground surface. Therefore, when the pitch angle, which is the blade angle with respect to the wind direction, is constant, the azimuths of the blades B _{1 to} B ₃ Angle θ (As shown in FIG. 6, it is an angle with respect to the vertical direction of the blade, where the azimuth angle of the blade reaching the top is 0 °, and indicates the angle along the rotation direction of the blade from the top) When is 0 °, the largest wind energy is received, and when the azimuth angle is 180 °, the smallest wind energy is received (see FIG. 7). That is, when the pitch angles of the blades B _{1 to} B ₃ are constant, the wind energy received varies depending on the azimuth angle θ, and the three blades B _{1 to} B ₃ receive different wind energy. As a result, the rotational moments acting on the blades B _{1 to} B ₃ are different, and the rotational balance of the _three blades B _{1 to} B ₃ is deteriorated. As a result, the power generation output is reduced and the wind power generator is configured. In order to increase the mechanical load of the structural members such as the blades B _{1 to} B ₃ and the power transmission shaft 53, the life of the mechanical structure of the wind turbine generator is shortened.

Therefore, in the wind power generator described above, as indicated by broken lines in FIG. 7, the wind energy received by each blade B _{1 to} B ₃ is substantially constant regardless of the height from the ground surface, that is, “Blade pitch angle control” is performed in which the rotational moment of each blade B _{1 to} B ₃ generated by wind energy is constant regardless of the azimuth angle θ.

Here, the "pitch angle" of blade B ₁ .about.B _3, an angle in relation to the crossing angle of the blade B ₁ .about.B ₃ with respect to the direction A of the wind, as shown in FIG. 8, the direction of the wind When the pitch angle when the angle of the blades B _{1 to} B _{3 with} respect to A is δ (> 90 °) is set to “0 °”, the pitch angle (0 °) is used as a reference to the wind direction A. If the positions inclined by the maximum angle in the direction where the crossing angle decreases and increase are defined as (+ αmax) and (−αmin), (+ αmax) and (−αmin) are the maximum pitch angle and the minimum pitch, respectively. It is called a corner. In FIG. 8, the shape of the blade B ₁ (B ₂ , B ₃ ) is schematically shown.

  Here, embodiments of “blade pitch angle control” are roughly classified into two types depending on whether or not a motor is used. The basic configuration of `` blade angle control '' that does not use a motor is a configuration in which the blade is rotated forward and backward by entering and exiting a rod of a hydraulic cylinder attached to each blade, and a hydraulic pump that drives the hydraulic cylinder includes: Located in the nacelle. In this configuration, since the hydraulic pump is disposed in the nacelle, there is a problem that maintenance is troublesome or difficult.

  On the other hand, in “blade angle control” using a motor, the motor is used in combination with a hydraulic pump and a hydraulic cylinder, and the blade is rotated forward and backward by operating the hydraulic pump and hydraulic cylinder by forward and reverse rotation of the motor. There are a configuration (see Patent Document 1) and a configuration in which the high-speed rotation of the motor is decelerated by a speed reducer to rotate the blade forward and backward. In “blade angle control” using a motor, the motor is driven and rotated so that the pitch angle of the blade changes during one rotation of the blade, and the blade is driven by wind energy. When the pitch angle is changed by rotation and the motor acting as a load of the revolving power of the blade is rotated, that is, the motor is rotated by external power and acts as a generator to regenerate. There is a “regenerative power generation time zone” for generating power, and both time zones occur alternately during continuous rotation of the blade. The “driving time zone” is a time zone in which a blade having an azimuth angle of around 180 ° is arranged at a position close to the ground surface, so that the wind energy received by the blade is increased (receives wind). The blade is a time zone in which the blade is rotated by the rotational torque of the motor. “Regenerative power generation time zone” is a time zone in which a blade having an azimuth angle of around 0 ° is arranged at a position farthest from the ground surface, and the wind energy received by the blade is reduced (the wind is released). Thus, the blade is in a time zone that is rotated by wind energy.

  In the conventional “blade angle control” using a motor, the generated regenerative power is invalidated (the voltage on the power source side becomes higher than the voltage of the regenerative power, and the regenerative power cannot be generated). In order to prevent this, the regenerative resistor provided in the inverter of the motor is passed through and converted into heat so that it is consumed. Therefore, the regenerative power was consumed wastefully and a resistance circuit (regenerative resistor) only for regenerative power consumption was required in the inverter.

JP 2009-68379 A

  In the blade pitch angle control using a motor, the regenerative electric power generated by rotating the blade by wind energy before and after the azimuth angle of 0 ° is consumed without heat consumption. By using it as electric power, it is an object to make effective use of regenerative power and to reduce power consumption, and to make it unnecessary to use a regenerative resistor in an inverter.

According to a first aspect of the present invention, there is provided a wind power generator in which a plurality of blades are attached to a hub at the tip of a power transmission shaft that is horizontally supported in a nacelle. A blade pitch angle control device that changes independently according to an angle, wherein the blade pitch angle control device is for changing the pitch angle of each blade by a reciprocating rotation motion obtained by converting the rotation of the blade pitch angle control device. The input AC power is converted into the same number of blades as the number of blades and output so that both the number of blades and the number of blades can be changed, and the rotation speed of each AC motor can be changed and the direction of rotation can be changed. and an inverter, wherein each of the main circuit of the inverter provided for each blade, is conducted to each other, by rotation of a particular blade, the main circuit of the blade The regenerative power has been made, is characterized in that the possible supply structure to the main circuit of the other blades.

  Controlled by the inverter, the rotation speed is changed, the rotation direction is changed, and the AC motor is rotated, whereby the azimuth angle of each blade is around 180 °, that is, each blade is close to the ground surface. In the portion, the blade is rotated to change the pitch angle so that the wind energy acting on the blade is increased, and the azimuth angle of each blade is about 0 °, that is, each blade is grounded. In the portion farthest from the surface, the blade is rotated to change the pitch angle so that the wind energy acting on the blade is reduced.

  And in the part where each blade is farthest from the ground surface, when the blade rotates so that the wind energy acting on the blade decreases, the AC motor is rotated by the rotation of the blade, and the regenerative power Is generated. The voltage of the regenerative power is converted into direct current by the switching circuit that constitutes the inverter and flows to the main circuit related to regenerative power generation that constitutes the inverter, and the voltage of the main circuit increases. In the invention of claim 1, since the same number of main circuits as the blades constituting the inverter are electrically connected to each other, there is a potential difference between the voltage of the main circuit related to regenerative power generation and the voltages of the other main circuits. Therefore, current flows from the main circuit related to regenerative power generation to the remaining main circuit, and the current (power) flowing to the other main circuit is used to drive the AC motor of the other main circuit. The The operations of generating and consuming the regenerative power are alternately repeated between the plurality of blades, so that the regenerative power supplied to the main circuit of any one blade is transferred to the other main circuits. It is supplied and used as electric power for the AC motor of the other main circuit.

  For this reason, in blade pitch angle control using a motor, the electric power of the motors of other blades is consumed without heat consumption of regenerative power generated by rotating the blades by wind energy before and after the azimuth angle of 0 °. As a result, it is possible to effectively use regenerative power and save power consumption. Further, since it is not necessary to incorporate a regenerative resistor for heat consumption of the regenerative power in the inverter as in the conventional circuit, the regenerative resistor that has been conventionally used becomes unnecessary.

  According to a second aspect of the present invention, in the first aspect of the invention, the blade pitch angle control device converts the reciprocating linear motion of the blade into a reciprocating rotational motion to directly change the pitch angle of each blade. The same number of hydraulic cylinders, the same number of hydraulic pumps as the number of blades for operating each hydraulic cylinder, the same number of AC motors as the number of blades for rotating each hydraulic pump, and the number of rotations of each AC motor And an inverter that converts the input AC power source into AC power of the same number as the number of blades and outputs the AC power.

  According to the second aspect of the invention, the AC motor, the hydraulic motor, and the hydraulic cylinder can be disposed in the hub provided at the tip of the power transmission shaft, so that the AC motor and each of the hydraulic devices are out of order. Even in this case, unlike the case where it is arranged in the nacelle, maintenance is easy.

  According to a third aspect of the present invention, the blade pitch angle control device according to the first aspect of the invention is characterized in that the blade pitch angle control device changes the pitch angle of each blade by a reciprocating rotational motion obtained by decelerating its own rotation and converting the motion. The AC power input to the blade so that both the number of AC motors, the speed reducer that decelerates the rotation of each AC motor, and the change in the rotation speed and conversion of the rotation direction of each AC motor are possible. And an inverter that outputs the same number of alternating currents as the number of alternating currents.

  Also in the invention of claim 3, the AC motor and the speed reducer can be arranged in a hub provided at the tip of the power transmission shaft, and since no hydraulic equipment is used, the configuration of the pitch angle control device is simple. It becomes.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, in any one of the plurality of main circuits constituting the inverter, each main circuit that has become overvoltage due to supply of regenerative power is provided. It is characterized by incorporating a regenerative resistor that drops the voltage of the circuit.

  For example, when all the blades are forcibly rotated by wind energy while the blades are stopped due to a failure, regenerative power is supplied to all the main circuits of the inverter, and the blades are electrically connected to each other. Since it is not consumed in the main circuit, the voltage is increased excessively, causing failure of the inverter. For this reason, if a regenerative resistor is incorporated in any one of the main circuits that are electrically connected to each other, if the voltage of each main circuit exceeds the set value, a current flows through the regenerative resistor. Is consumed, and the voltage is dropped to ensure safety.

  A fifth aspect of the present invention is a wind power generator provided with the blade pitch angle control device according to any one of the first to fourth aspects, wherein the effects of the respective inventions according to the first to fourth aspects are exhibited. The

  According to the present invention, in blade pitch angle control using a motor, the regenerative power generated by rotating the blade by wind energy before and after the azimuth angle of 0 ° is not consumed by the regenerative resistor. By using this as the power of the blade motor, it is possible to effectively use the regenerative power and reduce the power used, and to eliminate the need for using the regenerative resistor in the inverter.

It is a circuit diagram of a blade pitch angle control device in which an input power source to the inverter I is a three-phase alternating current. Is a diagram showing the relationship between the pitch angle with respect to the rotation angle of the blades B ₁ .about.B ₃ of three. It is a diagram showing the rotational speed and direction of rotation relationship between the AC motor M ₁ ~M ₃ with respect to the rotation angle of the three blades B ₁ ~B _3. It is a circuit diagram of a blade pitch angle control device in which an input power source to the inverter I is a single-phase alternating current. It is a schematic diagram of a wind power generator. It is an explanatory view of the azimuth angle of the blade B ₁ ~B _3. It is a figure which shows the relationship between the height from the ground surface in the state which performed the natural state and blade pitch angle control, and a wind energy. It is an illustration of the pitch angle α of the blade B ₁ ~B _3.

  Hereinafter, the present invention will be described in more detail with reference to a plurality of best examples.

First, the blade pitch angle control device of the first embodiment will be described with reference to FIGS. FIG. 1 is a circuit diagram of a blade pitch angle control device in which the input power source to the inverter I is a three-phase AC, and FIG. 2 shows the relationship of the pitch angle with respect to the rotation angles of the _three blades B _{1 to} B _3. FIG. 3 is a diagram showing the relationship between the rotation speed and the rotation direction of each AC motor M _{1 to} M ₃ with respect to the rotation angle of the _three blades B _{1 to} B ₃ . 2 and 3, ω is the angular velocity of the blades B _{1 to} B ₃ , and the horizontal axis represents the cumulative rotation angle (ωt) of the blades B _{1 to} B ₃ obtained by multiplying the angular velocity ω by time t. . In FIG. 1, an inverter I includes a rectifier circuit R for converting a three-phase AC power source into DC, and a switching circuit for converting the DC converted by the rectifier circuit R into a three-phase AC having a specific frequency characteristic. Three main circuits C _{1 to} C ₃ each having W and a capacitor 1 are provided. The three main circuits C _{1 to} C ₃ have the same configuration and correspond to the blades B _{1 to} B ₃ . The three-phase alternating current having the specific frequency characteristics described above is such that the pitch angle α with respect to the rotation angle of each of the blades B _{1 to} B ₃ is a sine wave whose phase is shifted by 120 ° as shown in FIG. In order to change, the rotation speed and the rotation direction with respect to the rotation angle of the blades B _{1 to} B _{3 in} the AC motors M _{1 to} M ₃ of the blades B _{1 to} B ₃ are 120 as shown in FIG. This means a three-phase alternating current that can be changed to a sine wave that is offset.

Further, each blade B ₁ .about.B _3, the hydraulic pump P ₁ to P ₃ which is driven by the AC motor M ₁ ~M _3, the hydraulic cylinder S ₁ ~ driven by the hydraulic pump P ₁ to P ₃ S ₃ is provided, and the hydraulic pumps P _{1 to} P ₃ are rotated forward and backward by the AC motors M _{1 to} M ₃ , and the hydraulic cylinders S _{1 are} rotated by forward and reverse rotation of the hydraulic pumps P _{1 to} P _3. to S ₃ of the rod in and out, the attachment portion of each blade B ₁ .about.B ₃ is rotated, and is configured so that the pitch angle α is changed.

The inverter I, the AC motors M _{1 to} M ₃ , the hydraulic pumps P _{1 to} P ₃ and the hydraulic cylinders S _{1 to} S ₃ are installed in a hub 54 that is integrally attached to the tip of the power transmission shaft 53 constituting the wind power generator. It is housed and rotates together with the hub 54. For this reason, each conducting wire 11 on the power source side of the three-phase alternating current and each conducting wire 12 connected to each of the main circuits C _{1 to} C ₃ constituting the inverter I are connected via the coupling 13.

The three-phase AC of the interphase voltage V ₁ is input to the rectifier circuit R of each of the main circuits C _{1 to} C ₃ of the inverter I and output as a DC voltage, and the pitch of the blades B _{1 to} B ₃ against wind energy. When the blades B _{1 to} B ₃ are present in a region where the angle α is maintained on the plus side (region below the axis L of the power transmission shaft 53), the DC voltage is applied to the switching circuit W. by being output as three-phase alternating current having a specific frequency characteristic as described above, the main circuit C ₁ AC motor M ₁ ~M ₃ corresponding to -C ₃ is driven, the AC motor M ₁ ~M the hydraulic cylinder S ₁ to S _3, which is driven by a hydraulic pump P ₁ to P ₃ and the hydraulic pump P ₁ to P ₃ which is driven by _3, the blade B ₁ .about.B ₃ is positive against the wind energy Holds the pitch angle α.

On the other hand, when the blades B _{1 to} B ₃ are present above the axis L of the power transmission shaft 53, the AC motors M _{1 to} M ₃ rotate in the opposite direction to the blades B ₁ to B ₃ . B ₃ is rotated to the side where the pitch angle α is negative with respect to the reference position, and acts to release wind energy. When this action occurs, the blades B _{1 to} B ₃ are rotated by the driving forces of the motors M _{1 to} M ₃ via the hydraulic pumps P _{1 to} P ₃ and the hydraulic cylinders S _{1 to} S _3. On the contrary, the motors M _{1 to} M ₃ are driven via the hydraulic pumps P _{1 to} P ₃ and the hydraulic cylinders S _{1 to} S ₃ by the force (rotational power) by which the blades B _{1 to} B ₃ are rotated by wind energy. , That is, a phenomenon in which electric power is generated by the motors M _{1 to} M ₃ acting as loads on the external power. The AC regenerative power generated by the motors M _{1 to} M ₃ is converted into DC power by the switching circuit W, and the DC voltage of the main circuits C _{1 to} C ₃ is increased.

As shown in FIG. 1, the pitch angle corresponding to the azimuth angle θ of each blade B _{1 to} B ₃ is sent from the command unit 31 to each switching circuit W from the command unit 31 to the main circuits C _{1 to} C _3. A control command value for controlling α is sent. In the command value acquisition unit 32, a command value calculated based on the azimuth angle θ, the rotation speed, the wind speed, and the power generation output of each blade B _{1 to} B ₃ is generated and transmitted to the command unit 31. Thereby, from the switching circuits W of the main circuits C _{1 to} C ₃ , the “specific frequency characteristics” calculated based on the azimuth angle θ, the rotational speed, the wind speed, and the power generation output of the blades B _{1 to} B _3. Are generated, AC motors M _{1 to} M ₃ are driven, and pitch angle control of each blade B _{1 to} B ₃ is executed.

In the present invention, as shown in FIG. 1, the conductive wires 14 of the main circuits C _{1 to} C ₃ constituting the inverter I are electrically connected to each other by a conductive wire 15. As a result, when the DC voltage of any one of the three main circuits C _{1 to} C ₃ is increased by the generation of AC regenerative power generated by the AC motors M _{1 to} M ₃ , the remaining The DC voltages of the two main circuits are also increased, and the DC voltages of the three main circuits C _{1 to} C ₃ become equal. That is, when the DC voltage of any one of the three main circuits C _{1 to} C ₃ is increased by the generation of AC regenerative power, the regenerative power converted to DC is supplied to the remaining two main circuits. Then, the AC motors corresponding to the remaining two main circuits are driven. As a result, the power used by the three-phase AC that is the power source is reduced.

Further, while each blade B ₁ .about.B ₃ stops because of a breakdown, if all of the blades B ₁ .about.B ₃ was forcibly rotated by wind energy, all of the main circuit C ₁ of the inverter I regenerative power is supplied to the -C _3, because they are not consumed in the main circuit C ₁ -C ₃ being electrically connected to each other, the voltage is excessively increased, causing failure of the inverter I. For this reason, when the regenerative resistor 2 is incorporated in parallel in any one of the main circuits C _{1 to} C ₃ that are electrically connected to each other, and the voltage of the one main circuit becomes higher than the set value, Safety is achieved by consuming electric power when current flows through the regenerative resistor 2 of the arbitrary one main circuit and dropping the voltage. That is, each main circuit C ₁ -C ₃ are, because they are electrically connected to each other, without integrated regenerative resistor to each main circuit C ₁ -C _3, any one of the main circuit C ₁ (C _2, By simply incorporating a regenerative resistor into C ₃ ), it is possible to prevent problems due to overvoltage of C _{1 to} C _{3 in} all main circuits.

In the blade pitch angle control device of the first embodiment, a three-phase alternating current of an interphase voltage V ₁ of a three-phase alternating current power source is input to an inverter I, and hydraulic pumps P _{1 to} P ₃ and hydraulic cylinders S _{1 to} S ₃ is used to change the pitch angle α of the blades B _{1 to} B ₃ , whereas the blade pitch angle control device of the second embodiment shown in FIG. A single-phase alternating current of line voltage V ₂ is input, and the rotation of AC motors M _{1 to} M ₃ is decelerated by reduction gears D _{1 to} D ₃ to change the pitch angle α of blades B _{1 to} B _3. However, the driving force of the AC motors M _{1 to} M ₃ is used as driving means for changing the pitch angle α of the blades B _{1 to} B ₃ . Therefore, in the description of the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and only the parts different from the first embodiment will be described to avoid duplication.

FIG. 4 is a circuit diagram of a blade pitch angle control device in which the input power source to the inverter I is a single-phase alternating current. That is, a single-phase alternating current relating to a potential difference generated between a neutral point O that is a coupling point of each of the three coils and one end of each of the three coils is generated by each of the main circuits C _{1 to} C ₃ of the inverter I. Input to the rectifier circuit R. In FIG. 4, reference numeral 16 denotes a conducting wire connected to the neutral point O of the three coils, and is connected to the conducting wire 18 on the hub side via the coupling 17. Each blade pitch angle control device of Examples 1 and 2 is different in whether the AC input to the rectifier circuit R of the inverter I is three-phase or single-phase, but the configuration of the inverter I itself is This is common to the first and second embodiments.

Further, the rotations of the AC motors M _{1 to} M ₃ driven by the three-phase AC output from the switching circuit W of the inverter I are decelerated by the reduction gears D _{1 to} D ₃ to attach the blades B _{1 to} B ₃ . The pitch angle α which is the angle of the part is changed. In FIG. 4, reference numeral 21 denotes a positive clutch such as a tooth clutch that connects the drive shafts of the AC motors M _{1 to} M ₃ and the input shafts of the reduction gears D _{1 to} D ₃ .

For this reason, the single-phase alternating current extracted from the three-phase alternating current that is the power source is input to each rectifier circuit R of the main circuits C _{1 to} C ₃ of the inverter I, and the three-phase alternating current output from each switching circuit W When each AC motor M _{1 to} M ₃ is driven, the number of rotations and the direction of rotation of the motors M _{1 to} M _{3 with} respect to the rotation angle of the blades B _{1 to} B ₃ change as shown in FIG. The pitch angle α of B _{1 to} B ₃ changes as shown in FIG. 2, and the load on the wind energy during the rotation of the blades B _{1 to} B ₃ hardly changes and the rotational moment is almost constant. It becomes. As a result, the blades B _{1 to} B ₃ rotate stably.

Further, during the rotation of the blades B ₁ .about.B _3, and the rotational force of the blade B ₁ .about.B ₃ AC motor M ₁ ~M ₃ is rotated, AC regenerative power is generated, constituting the inverter I When the voltage of any one of the three main circuits C _{1 to} C ₃ becomes high, the voltages of the remaining two main circuits conducted by the conductive line 15 also become high, and the remaining two Regarding the two main circuits, the configuration in which the supplied regenerative power is consumed for driving the AC motor is exactly the same as in the first embodiment.

  In the above embodiment, the number of blades is “3”, but the present invention can be implemented regardless of the number of blades.

B _{1 to} B ₃ : Blade C _{1 to} C ₃ : Main circuit
I: Inverter M ₁ ~M _3: AC motor P ₁ to P _3: hydraulic pump S ₁ to S _3: hydraulic cylinder
α: Blade pitch angle
θ: Blade azimuth angle
2: Regenerative resistance
15: Main circuit conduction line
31: Command section
32: Command value acquisition unit
52: Nasser
53: Power transmission shaft
54: Hub

Claims (5)

Blade pitch angle control in which a plurality of blades are attached to a hub at the tip of a power transmission shaft that is horizontally supported in the nacelle, and each pitch angle of the blades is independently changed in accordance with the azimuth angle. A device,
The blade pitch angle control device has the same number of AC motors as the number of blades for changing the pitch angle of each blade by a reciprocating rotational motion obtained by converting the rotation of itself, and the change in the rotational speed of each AC motor. And an inverter that converts the input AC power source into the same number of ACs as the number of blades and outputs the AC power so that both conversions in the rotation direction are possible,
Each main circuit of the inverter provided for each blade is electrically connected to each other, and regenerative power generated in the main circuit of the blade is supplied to the main circuit of the other blade by rotation of the specific blade. A blade pitch angle control device for a wind turbine generator, characterized in that the configuration is possible.   The blade pitch angle control device operates as many hydraulic cylinders as the number of blades for directly changing the pitch angle of each blade by converting its own reciprocating linear motion into reciprocating rotational motion, and each of the hydraulic cylinders. As many hydraulic pumps as the number of blades to be used, AC motors as many as the number of blades for rotating the hydraulic pumps, and changes in the rotational speeds of the AC motors and conversion of the rotational direction are possible. The blade pitch angle control device for a wind turbine generator according to claim 1, further comprising: an inverter that converts an input AC power source into an AC power having the same number as the number of blades and outputs the same.   The blade pitch angle control device includes the same number of AC motors as the number of blades for changing the pitch angle of each blade by a reciprocating rotational motion obtained by decelerating the rotation of the blade and converting the motion, and the rotation of each AC motor. A speed reducer that decelerates, and an inverter that converts the input AC power source into the same number of ACs as the number of blades and outputs it so that both the change in the rotation speed of each AC motor and the conversion of the rotation direction are possible. The blade pitch angle control device for a wind turbine generator according to claim 1, wherein the blade pitch angle control device is provided.   The regenerative resistor for dropping the voltage of each main circuit that has become an overvoltage due to the supply of regenerative power is incorporated in any one main circuit among the plurality of main circuits constituting the inverter. Item 4. A blade pitch angle control device for a wind turbine generator according to any one of Items 1 to 3.   A wind turbine generator comprising the blade pitch angle control device according to any one of claims 1 to 4.

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