JPH06117353A - Wind power generator - Google Patents

Abstract

PURPOSE:To provide a wind power generating device furnished with a control device to control output of a generator to increase in accordance with wind force at the time while holding stable supply of rated output even when output of a motive power-electric power converter is more than the rated output. CONSTITUTION:A wind power generating device is constituted of a windmill (1) to convert wind force energy to motive power, a motive power-electric power converter (3) to output by way of converting the motive power to electric power and a load control device (6) to control generating output of the motive power-electric power converter (3). By carrying out load variable control of the generating output of the motive power-electric power converter (3) by the load control device (6) up to a specified range of more than a rated output and properly changing a pitch angle of a blade (1a) of the windmill (1) by a pitch angle control device (2) provided on the windmill (1), the generating output is increased within the specified range of more than the rated output in accordance with increase of wind force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a wind turbine generator including a wind turbine that converts wind energy into power and a power-power converter that converts the power into electric power and outputs the power. The present invention relates to an improvement of a wind turbine generator including a control device capable of variably controlling the output of a converter.

[0002]

2. Description of the Related Art Conventionally, wind energy is converted into power by a wind turbine, and the power is converted into electric power by a power-power converter, and more specifically, a wind power generator that drives a generator with the power is momentarily. How to efficiently generate electric power from the changing wind force is a problem, and usually a control device for efficiently generating electric power is installed. The control device described above electrically controls the generator so that the output of the generator reaches the maximum output according to the wind force at that time until the output of the generator reaches the rated output, and the output of the generator reaches the rated output. After that, there was a control device that controls the output of the generator so as to maintain a constant rated output (see Japanese Patent Laid-Open No. 63-39500).

[0003]

However, in the conventional wind turbine generator of the above-mentioned type, after the output of the generator reaches the rated output, the load control device performs the constant load control so that the output becomes constant. Since it has been controlled so that the increased amount is released without being converted to electric power, it has the advantage that a stable rated output can be obtained, but it is said that the energy generation efficiency for wind power after reaching the rated output is good. However, there is a problem that various energy losses are required to keep the output constant. Therefore, the present invention solves the problems of the conventional wind turbine generator described above, and generates power according to the wind force at that time while maintaining stable supply of output even if the output of the power-power converter is equal to or higher than the rated output. An object of the present invention is to provide a wind turbine generator equipped with a control device that controls so that the output of the machine increases.

[0004]

In order to achieve the above object, a wind turbine generator of the present invention is a wind turbine that converts wind energy into power, and a power-power converter that converts the power into electric power and outputs the electric power. A load control device that controls the power generation output of the power-power conversion device, even if the output of the power-power conversion device in the load control device is equal to or higher than the rated output, the output according to the wind force within a predetermined range. It is characterized in that the load variable control is performed so as to increase.

[0005]

In the wind power generator of the present invention configured as described above, even after the output of the power-power converter reaches the rated output, the output increases in accordance with the increase of the wind power within the predetermined range. As described above, the load control device performs the variable load control, and the increase in the wind force after the load exceeds the rated output can be efficiently used for power generation.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the control device for a wind turbine generator according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic block diagram showing the outline of the basic configuration of an embodiment of the wind turbine generator of the present invention. In the figure, reference numeral 1 denotes a wind turbine, which is provided with a pitch angle control device 2 whose output shaft (not shown) is connected to a power-power conversion device 3. The pitch angle control device 2 described above uses the blades according to the centrifugal force of the wind turbine 1 when the rotation speed of the wind turbine 1 exceeds a predetermined value.
A mechanical control unit (not shown) that mechanically changes the pitch angle of 1a and a mechanical control unit that receives a control signal from the control signal output unit 4 when the wind force exceeds a certain value, such as a motor. And an electric control unit (not shown) for forcibly driving the blade 1a to change the pitch angle of the blade 1a. The control signal output unit 4 is configured to receive the output from the wind force sensor 5 and output a control signal to the electric control unit of the pitch angle control device 2 when the wind force exceeds a predetermined value.

The power-power converter 3 is an induction generator 3a.
And an inverter device 3b. The inverter device 3b has an exciting function for generating power in the induction power generator 3a, a function for converting the generated alternating current into a direct current, and a rotation speed of the wind turbine 1. A converter 3c having a function of changing the frequency of the induction power generator 3a according to the above, a power storage unit 3e (a capacitor in this embodiment) that stores the output from the converter 3c, and an alternating current according to an external load. It is composed of a converter 3d that outputs a current. The power-power converter 3
Is provided with a load control device 6. The configuration of the control device 6 will be described below. The output frequency from the rotation speed sensor 6a is converted into a voltage by the frequency-voltage converter 6b, and based on this voltage, that is, the current rotation speed of the wind turbine 1 (hereinafter, simply referred to as the rotation speed N in this specification). Output command value reading section 6c
The output command signal (ideal output) is read from the rotational speed-output map stored in advance. On the other hand, the output detection unit 6d is a conversion unit.
The output (current output) converted by 3c is detected, and the current output and the command output (ideal output) from the output command value reading unit 6c are compared by the comparison unit 6e, and the difference is the control signal processing. Output to part 6f. The control signal processing unit 6f performs control based on the difference between the current power and the ideal power input from the comparison unit 6e and the voltage (current rotation speed) input via the frequency-voltage converter 6b. Converts the signal by calculating it
The load is controlled by changing the torque by changing the excitation frequency to the induction generator 3a in the converter 3c.

FIG. 2A shows an example of a map of the rotational speed N-output P stored in advance in the output command value reading section 6c.
In the figure, Ncin is the rotation speed at which the induction power generation device 3a starts generating power (hereinafter referred to as power generation start rotation speed Ncin in this specification), and NR is the rotation speed at rated voltage (hereinafter, rated rotation speed N).
R), Nmax is the limit rotational speed at which the wind turbine 1 can rotate (hereinafter referred to as maximum rotational speed Nmax), PR is the rated output, and Pmax is the maximum output. The data indicated by the solid line in FIG. 2B is a map showing the torque characteristic corresponding to the rotation speed N in FIG. 2A, that is, the control characteristic of the load control device 6, and the output command value reading unit. Figure 6 shows this map in 6c
It may be stored instead of the map of (a). However, when the map of FIG. 2B is stored, it goes without saying that the configuration of the load control device 6 is different from that of the present embodiment, and for example, an optimum torque is output according to the output of the rotation speed sensor 6a. The command value reading unit 6c may be configured to read the torque, multiply the torque by the rotation speed N to calculate the electric power, and input the electric power to the comparing unit 6e.

The load control device 6 reads the optimum output corresponding to the current rotation speed N input from the rotation speed sensor 6a from the output command value reading portion 6c from this map, and the power-power conversion device according to the output. 3 is subjected to variable load control. Specifically, the excitation frequency and voltage to the induction generator 3a are controlled in the vicinity of the power generation start speed Ncin according to the wind speed condition (more specifically, the frequency is controlled so that the output is proportional to the cube of the wind speed). , The wind speed, that is, the rotational speed N at that time reaches a predetermined value (NC in FIG. 2), and then the output is output until the rotational speed N reaches the rated rotational speed NR as indicated by the symbol a in FIG. 2 (b). Is controlled by changing the torque, that is, the slip ratio of the induction power generation device 3a so as to increase in proportion to the rotation speed N. Less than,
This is referred to as slip rate adjustment control I. After the rotation speed N reaches the rated rotation speed NR, that is, after the output reaches the rated output,
When the wind power (wind speed) further increases, the torque, that is, the slip rate of the induction generator 3a is controlled to be constant (hereinafter referred to as constant slip rate control), as indicated by symbol b in FIG. 2 (b). At the same time, the pitch angle of the blades 1a of the wind turbine 1 is mechanically changed by the mechanical control unit of the pitch angle control device 2 according to the wind force, and the wind speed increases until the rotation speed N reaches the maximum rotation speed Nmax. The output of the induction generator 3a is increased. For example, as a configuration of the mechanical control unit, the mechanical control unit is provided with a weight so that the centrifugal force of the wind turbine 1 spreads outward when the rotational speed of the wind turbine 1 reaches a certain number of revolutions. A configuration is conceivable in which the pitch angle of the blade 1a is changed via a link mechanism or the like.

In this way, after the rotational speed N reaches the rated rotational speed NR, that is, after reaching the rated output, when the wind power further increases, the torque of the induction generator 3a, that is, the slip ratio is made constant, Further, in the conventional load constant control in which the output is constant immediately after reaching the rated output, by performing the load variable control in which the output increases in accordance with the increase in the wind force until the rotational speed N exceeds the maximum rotational speed Nmax. Predicted failure,
That is, the torque is inversely proportional to the rotation speed N, and the wind turbine 1
It becomes a negative damper for the torsional vibration system (not shown) of the rotating shaft (not shown), and the vibration of the rotating shaft does not increase. Further, in the past, in order to make the output constant after the rotation speed reaches the rated rotation speed NR, the energy required for the high speed pitch conversion control of the blades 1a of the wind turbine 1 is not used, and the output is made constant. Therefore, it becomes possible to effectively utilize the wind force that has been released to the limit.

The operation of the wind turbine generator will be described below with reference to the flow chart of FIG. 3, which is an operation explanatory diagram of the load controller 6 in the wind turbine generator configured as described above.
The control signal processing unit 6f outputs a control signal to prevent the induction power generation device 3a from being excited by the conversion unit 3c before the rotation speed N reaches the power generation start rotation speed Ncin, and maintains the power generation standby state (step 1). When the rotation speed N reaches the power generation start rotation speed Ncin (preferably 480 rpm), the control signal processing unit 6f converts the conversion unit 3c.
A control signal is output to and the conversion unit 3c excites the induction generator 3a to start power generation (steps 2 to 3). As described above, the control signal processing unit 6f includes the rotation speed sensor 6a, the output command value reading unit 6c, and the output detecting unit 6d until the output reaches the rated output.
A slip ratio adjusting control I (step 4) that outputs a control signal for changing the torque of the induction power generating device 3a, that is, the slip ratio based on the information of the above, and controls the slip ratio of the induction power generating device 3a via the conversion unit 3c. If the rotation speed N becomes equal to or lower than the power generation start rotation speed Ncin after the operation once (step 6), the excitation of the induction generator 3a is interrupted and the power generation standby state is resumed (step 6). Return to 1). The rotational speed N is the rated rotational speed N while the slip ratio adjustment control I is being performed.
When R is exceeded (step 5), the control signal processing unit 6f outputs a control signal to the conversion unit 3c so that the slip ratio of the induction generator 3a becomes constant, and the slip ratio of the induction generator 3a, that is, the torque becomes constant. A constant slip ratio control is performed (step 7). This constant slip rate control is continued until the rotational speed N exceeds the maximum rotational speed Nmax (step 8) or becomes less than the rated rotational speed NR (step 6), and once the rotational speed N exceeds the maximum rotational speed Nmax. (Step 8),
The rotation speed N is reduced until the rotation speed N becomes the maximum rotation speed Nmax or less.
As shown in FIG. 2 (b), the torque of the induction generator 3a, that is, the slip rate, is reduced in accordance with the increase of the electric power, and the slip rate adjustment control II (step 9) is performed to prevent the power-power converter 3 from being overpowered. Refer to the range indicated by the symbol c in FIG. When the rotation speed N becomes equal to or lower than the rated rotation speed NR during the constant slip rate control (step 5), the rotation speed N is the power generation start rotation speed N.
If it is greater than or equal to cin (step 6), the slip ratio adjustment control I is performed (step 4), and if it is smaller than the power generation start rotational speed Ncin (step 5), the excitation from the conversion unit 3c is turned off to enter the power generation standby state (step 1). Return.

Provided to the wind turbine 1 while the load control device 6 is performing the constant slip rate control (step 7), that is, when the rotation speed N of the wind turbine 1 is larger than the rated rotation speed NR and smaller than the maximum rotation speed Nmax. The mechanical control unit of the pitch angle control device 2 is operated to appropriately change the pitch angle of the blades 1a of the wind turbine 1 according to the wind force at that time, that is, the centrifugal force generated by the rotation of the wind turbine 1 according to the wind force. , Pitch angle control is performed so that the output increases as the wind power increases. Further, a significant increase in wind force that cannot control the rotation speed N of the wind turbine 1 by the pitch angle control of the mechanical control unit is detected by the wind force sensor 5, and the control signal output unit 4 outputs based on the detection result. The electric control unit of the pitch angle control device 2 operates according to the control signal to forcibly change the pitch angle of the blades 1a of the wind turbine 1 so as to maintain the standby state until the wind power weakens. For example, the pitch angle of the blades 1a that can be controlled by the mechanical control unit is set to about 4 ° to 35 ° (this setting is, for example, configured such that the mechanical control unit uses the centrifugal force to perform pitch conversion). If this is the case, it can be easily set by limiting the spreading distance of the weight that spreads outward by centrifugal force), and measure the wind speed (wind force) Vmax in advance so that the pitch angle exceeds the maximum angle of 35 °. It is stored in the control signal output unit 4, and when the wind force sensor 5 detects the wind speed (wind force) Vmax, a control signal is output from the control signal output unit 4 and provided in the electric control unit in the pitch angle control device 2. Means for forcibly changing the pitch (eg motor)
Is operated to forcibly change the pitch angle to 90 °,
Wind speed (wind force) so that the blades 1a of the windmill 1 do not receive wind
It may be configured to wait for the rotation speed N of the wind turbine 1 to decrease.

The wind turbine generator of this embodiment is preferably provided with a timer circuit so that the rotation speed N of the wind turbine 1 is the maximum rotation speed N.
After reaching the max (that is, the maximum output), the time is measured when the rotation speed N of the wind turbine 1 is maintained between the rated rotation speed NR and the maximum rotation speed Nmax for a long time, and the time is determined to be a predetermined value. When the time is exceeded, the load control device 6 controls the power-power conversion device 3 so as to be in the power generation standby state (step 1 in FIG. 3), and the pitch angle control device 2 sets the pitch angle of the blade 1a to 90 °. Can be controlled to prevent over-rotation of the wind turbine 1. Further, the wind turbine generator of this embodiment is configured such that the load control device 6 performs variable load control until the output reaches the maximum output Pmax, that is, the rotation speed reaches the maximum rotation speed Nmax. The power generation device is not limited to the embodiment, and the load control device 6 is a power source.
Even if the output of the power conversion device 3 reaches the rated output, the load variable control may be performed so that the output increases within a predetermined range. For example, at the rated output PR or higher, Set an appropriate output Px that is not the output Pmax,
The variable load control may be performed until the output of the power-power converter 3 reaches its output Px. Further, the wind power generator of the present embodiment is configured such that when the output becomes equal to or higher than the rated output, the load controller 6 controls the slip ratio of the induction generator 3a, that is, the torque to be constant. As shown by the broken line in (b), it goes without saying that the torque may be slightly increased as the rotation speed N increases. When controlled in this way, the torque exerts a damper effect on the rotational inertia system of the wind turbine 1, and the stability against rotational fluctuation is increased.

[0014]

According to the wind power generator of the present invention, even if the wind power further increases after the output of the power-power converter reaches the rated output, the output increases in accordance with the increase of the wind power within a predetermined range. Since the load control device performs the load variable control as described above, it is possible to effectively utilize the increase in the wind force after the output of the power-power conversion device reaches the rated value to generate electric power.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a basic configuration of an embodiment of a wind turbine generator of the present invention.

2 (a) is a rotation speed-output characteristic diagram showing an example of a map stored in an output command value reading unit in FIG. 1. FIG. (b)
FIG. 3 is a rotational speed-torque characteristic diagram corresponding to the characteristic diagram of FIG.

FIG. 3 is a flowchart showing an embodiment of the operation of the load control device.

[Explanation of symbols]

 1 Windmill 1a Blade 2 Pitch angle control device 3 Power-electric power conversion device 3a Induction power generation device 3b Inverter device 3c Conversion part 3d Conversion part 3e Electric storage part 4 Control signal output part 5 Wind sensor 6 Load control device 6a Rotation speed sensor 6b Frequency- Voltage converter 6c Output command value readout section 6d Output detection section 6e Comparison section 6f Control signal processing section

Claims (1)

[Claims] 1. A wind turbine for converting wind energy into power (1)
And a power-power converter for converting the power into electric power and outputting the electric power
(3) and a load control device (6) that controls the power generation output of the power-power conversion device (3), and the output of the power-power conversion device (3) is rated output by the load control device (6). Even if it becomes the above, it is constituted so that load variable control may be performed so that an output may increase within a predetermined range according to wind power.