Vertical axis windmill power generation unit including overspeed suppression mechanism and method for controlling vertical axis windmill power generation unit including overspeed suppression mechanism

Abstract

To provide a vertical axis windmill power generation unit including an overspeed suppression mechanism that eliminate the need of a braking resistor, and to provide a method for controlling a vertical axis windmill power generation unit.SOLUTION: A vertical axis windmill power generation unit including an overspeed suppression mechanism includes: power generator output detection means 60 for detecting power that is output from a rectifier 50; and an opening switch 70 disposed between the rectifier 50 and a DC / AC converter 90. A controller opens the opening switch 70 to stop power supply to the DC / AC converter 90 when the power generator output detection means 60 detects a specified value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vertical axis wind turbine, and more particularly to a vertical axis wind turbine power generating unit equipped with an over-rotation suppression mechanism, and a control method for the vertical axis wind turbine power generating unit. [Background technology]

[0002] When the wind speed increases, the rotation speed of the wind turbine also increases, and it is necessary to take measures to ensure the strength of the wind turbine and to protect the electrical circuit.

[0003] As shown in Figure 9, when the input power to the power conditioner exceeds a certain value, power is consumed by the braking resistor to protect the power conditioner, and a braking torque is generated by a high current in the generator to slow down the wind turbine. Incidentally, horizontal axis wind turbines are generally large for commercial reasons, and installation locations are limited to coastlines and mountainous areas exposed to strong winds. On the other hand, small vertical axis wind turbines can generate electricity even with an average wind speed of about 3.7 m / s, so they can be installed almost anywhere in Japan, and are suitable for local production and consumption, where electricity is generated locally, making them a highly anticipated type of wind turbine. The applicant has already proposed a vertical axis wind turbine that includes a base having a generator, a rotating part that rotates about an axis vertical to the base, and a number of wind turbine blades that are connected to the rotating part via an arm and rotate about the vertical axis, the arm having a movable part for suppressing over-rotation that can rotate about an arm axis connecting the rotating part and the wind turbine blades, the movable part being equipped with an over-rotation suppression inductor that tilts the movable part about the arm axis due to the action of centrifugal force, aerodynamic force, and gravity generated when the wind turbine rotates, and returns the movable part to its initial state when the wind turbine stops rotating (Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-10424 A [Patent Document 2] Patent Publication No. 2022-108917 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional method of consuming power with a braking resistor requires a braking resistor, which is a major factor in increasing costs and eliminates the advantage of a small vertical axis wind turbine. The vertical axis wind turbine equipped with the over-speed suppression mechanism proposed by the applicant has the characteristic that it will not rotate above a set rotation speed even if the generator becomes unloaded due to strong wind conditions.

[0005] An object of the present invention is to provide a vertical axis wind turbine generating unit having an over-speed suppression mechanism that does not require a braking resistor, and a control method for the vertical axis wind turbine generating unit. [Means for solving the problem]

[0006] The vertical axis wind turbine generating unit with an over-rotation suppression mechanism of the present invention described in claim 1 is a vertical axis wind turbine generating unit with an over-rotation suppression mechanism, comprising a vertical axis wind turbine with an over-rotation suppression mechanism, a generator that converts rotational energy of the vertical axis wind turbine into electrical energy, and a rectifier that converts AC power output from the generator into DC power, and is characterized in that it has a generator output detection means that detects the power output from the rectifier, and an open switch that is disposed between the rectifier and the DC / AC converter, and a control unit that opens the open switch to stop power supply to the DC / AC converter when the generator output detection means detects a predetermined value. The present invention as set forth in claim 2 is a vertical axis wind turbine power generating unit equipped with the over-rotation suppression mechanism as set forth in claim 1, characterized in that the vertical axis wind turbine comprises a base having the generator, a rotating part rotating about a vertical axis relative to the base, and a plurality of wind turbine blades connected to the rotating part via an arm and rotating about the vertical axis, the over-rotation suppression mechanism comprises a movable part for over-rotation suppression provided on the arm and rotatable about an axis of an arm axis connecting the rotating part and the wind turbine blades, and an over-rotation suppression inductor provided on the movable part, tilting the movable part about the arm axis by the action of centrifugal force, aerodynamic force, and gravity generated when the wind turbine blades rotate, and returning the movable part to its initial state when the rotation of the wind turbine blades stops, and the vertical axis wind turbine does not rotate at or above a set rotation speed due to the aerodynamic force acting on the movable part. The present invention as set forth in claim 3 is characterized in that, in a vertical axis wind turbine generating unit equipped with the over-rotation suppression mechanism as set forth in claim 1, the generator is PWM controlled so as to operate at a preset operating point. The control method for a vertical axis wind turbine generating unit equipped with an over-speed suppression mechanism of the present invention described in claim 4 is a control method for a vertical axis wind turbine generating unit equipped with an over-speed suppression mechanism, comprising a vertical axis wind turbine equipped with an over-speed suppression mechanism, a generator converting rotational energy of the vertical axis wind turbine into electric energy, and a rectifier converting AC power output from the generator into DC power, and inputting the power output from the rectifier to a DC / AC converter, characterized in that the control method further comprises generator output detection means for detecting the power output from the rectifier, and an open switch disposed between the rectifier and the DC / AC converter, and when the generator output detection means detects a predetermined value, the open switch is opened to stop the power supply to the DC / AC converter. The present invention as set forth in claim 5 is a method for controlling a vertical axis wind turbine power generating unit equipped with an over-rotation suppression mechanism as set forth in claim 4, characterized in that the vertical axis wind turbine comprises a base having the generator, a rotating part rotating about an axis vertical to the base, and a plurality of wind turbine blades connected to the rotating part via an arm and rotating about the vertical axis, the over-rotation suppression mechanism comprises a movable part for over-rotation suppression provided on the arm and rotatable about an axis of an arm axis connecting the rotating part and the wind turbine blades, and an over-rotation suppression inductor provided on the movable part, tilting the movable part about the arm axis by the action of centrifugal force, aerodynamic force, and gravity generated when the wind turbine blades rotate, and returning the movable part to its initial state when the rotation of the wind turbine blades stops, and the vertical axis wind turbine does not rotate at or above a set rotation speed due to the aerodynamic force acting on the movable part. The present invention as set forth in claim 6 is characterized in that in the control method for a vertical axis wind turbine generating unit equipped with the over-rotation suppression mechanism as set forth in claim 4, the generator is PWM controlled so as to operate at a preset operating point. Effect of the Invention

[0007] According to the present invention, the DC / AC converter can be protected by opening the open switch when the generator output detection means detects a predetermined value, and a braking resistor is not required because the over-speed suppression mechanism prevents the vertical axis wind turbine from rotating at or above a set rotation speed. [Brief description of the drawings]

[0008] [Figure 1] Overall configuration diagram of a vertical axis wind turbine equipped with an over-rotation suppression mechanism according to one embodiment of the present invention. [Diagram 2] A perspective view of the main part of the vertical axis wind turbine. [Diagram 3] A block diagram showing a vertical axis wind turbine power generating unit equipped with an over-rotation suppression mechanism according to the present embodiment and an explanatory diagram of operating points. [Figure 4] Graph explaining a method for setting generator characteristics in a vertical axis wind turbine equipped with an overspeed suppression mechanism according to an embodiment of the present invention. [Diagram 5]A graph showing the pure shaft torque characteristics of the wind turbine before subtracting the no-load torque and the approximate curve of the operating point (Figure 4(d)) in the wind speed range V = 3 m / s to 16 m / s. [Figure 6] A graph showing the torque curves corresponding to the allowable values ​​of the PWM control and DC / AC converter, and the maximum allowable rotation speed of the generator, in addition to the graph shown in FIG. [Figure 7] Graph showing an example of a method for setting an operating point in PWM control [Figure 8] The wind turbine rotation speed and shaft torque characteristics, and the wind turbine power curve predicted when the operating points are set as shown in Fig. 7 [Figure 9] Graph showing another embodiment of the operating point setting method in PWM control [Figure 10] The wind turbine rotation speed and shaft torque characteristics, and the wind turbine power curve predicted when the operating points are set as shown in Fig. 9 [Figure 11] Graph showing a comparison of the operating points shown in FIG. 7 and the operating points shown in FIG. 9 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A vertical axis wind turbine power generating unit with an over-rotation suppression mechanism according to a first embodiment of the present invention has generator output detection means for detecting power output from a rectifier, and an open switch disposed between the rectifier and a DC / AC converter, and a control unit opens the open switch to stop power supply to the DC / AC converter when the generator output detection means detects a predetermined value. According to this embodiment, when the generator output detection means detects a predetermined value, the open switch is opened to stop the power supply to the DC / AC converter without switching to a braking resistor, thereby protecting the DC / AC converter, and since the over-speed suppression mechanism prevents the vertical axis wind turbine from rotating at or above a set rotation speed, a braking resistor is not required.

[0010] The second embodiment of the present invention is a vertical axis wind turbine power generating unit with an over-rotation suppression mechanism according to the first embodiment, in which the vertical axis wind turbine comprises a base having a generator, a rotating part which rotates around a vertical axis relative to the base, and a plurality of wind turbine blades which are connected to the rotating part via an arm and rotate around the vertical axis, and the over-rotation suppression mechanism comprises a movable part for over-rotation suppression which is provided on the arm and can rotate around an axis of the arm axis which connects the rotating part and the wind turbine blades, and an over-rotation suppression inductor which is provided on the movable part and tilts the movable part around the arm axis by the action of centrifugal force, aerodynamic force, and gravity generated when the wind turbine blades rotate, and returns the movable part to its initial state when the wind turbine blades stop rotating, and the aerodynamic force acting on the movable part prevents the vertical axis wind turbine from rotating at a speed above the set rotation speed. According to this embodiment, the power supply to the DC / AC converter can be stopped without requiring a braking resistor.

[0011] In a third embodiment of the present invention, in a vertical axis wind turbine generating unit equipped with the over-rotation suppression mechanism according to the first embodiment, the generator is PWM controlled so as to operate at a preset operating point. According to this embodiment, the control target of the generator can be appropriately set, and the generator can be operated without causing a large decrease in the annual power generation amount.

[0012] A control method for a vertical axis wind turbine generating unit equipped with an over-rotation suppression mechanism according to a fourth embodiment of the present invention has generator output detection means for detecting power output from a rectifier, and an opening switch arranged between the rectifier and a DC / AC converter, and when the generator output detection means detects a predetermined value, the opening switch is opened to stop power supply to the DC / AC converter. According to this embodiment, when the generator output detection means detects a predetermined value, the open switch is opened to stop the power supply to the DC / AC converter without switching to a braking resistor, thereby protecting the DC / AC converter, and since the over-speed suppression mechanism prevents the vertical axis wind turbine from rotating at or above a set rotation speed, a braking resistor is not required.

[0013] A fifth embodiment of the present invention is a control method for a vertical axis wind turbine power generating unit with an over-rotation suppression mechanism according to the fourth embodiment, in which the vertical axis wind turbine comprises a base having a generator, a rotating part rotating around a vertical axis relative to the base, and a plurality of wind turbine blades connected to the rotating part via an arm and rotating around the vertical axis, and the over-rotation suppression mechanism comprises a movable part for over-rotation suppression provided on the arm and rotatable around an axis of the arm axis connecting the rotating part and the wind turbine blades, and an over-rotation suppression inductor provided on the movable part, which tilts the movable part around the arm axis by the action of centrifugal force, aerodynamic force, and gravity generated when the wind turbine blades rotate, and returns the movable part to its initial state when the wind turbine blades stop rotating, and the aerodynamic force acting on the movable part prevents the vertical axis wind turbine from rotating at a speed above a set speed. According to this embodiment, the power supply to the DC / AC converter can be stopped without requiring a braking resistor.

[0014] A sixth embodiment of the present invention is a control method for a vertical axis wind turbine generating unit equipped with an over-rotation suppression mechanism according to the fourth embodiment, in which the generator is PWM controlled so as to operate at a preset operating point. According to this embodiment, the control target of the generator can be appropriately set, and the generator can be operated without causing a large decrease in the annual power generation amount. EXAMPLES

[0015] A control method for a vertical axis wind turbine generating unit equipped with an over-rotation suppression mechanism according to one embodiment of the present invention will be described below. FIG. 1 is an overall configuration diagram of a vertical axis wind turbine equipped with an over-rotation suppression mechanism according to this embodiment, and FIG. 2 is a perspective view of a main part of the same vertical axis wind turbine. The vertical axis wind turbine equipped with an over-rotation suppression mechanism according to this embodiment comprises a vertical axis wind turbine 10 and an over-rotation suppression mechanism 20. The vertical axis wind turbine 10 comprises a base 11 equipped with a speed increaser 30 (see FIG. 3) and a generator 40 (see FIG. 3), a rotating part 12 that rotates around a vertical axis Z relative to the base 11, and a plurality of wind turbine blades 14 that are connected to the rotating part 12 via arms 13 and rotate around the vertical axis Z. In this embodiment, there are three wind turbine blades 14. The base 11 is the part that becomes the foundation of the vertical axis wind turbine. The base 11 includes legs 11a formed at a predetermined height, and a housing section 11b that houses the speed increaser 30 and the generator 40. The wind turbine blades 14 are disposed at a predetermined height from the installation surface by the legs 11a. The wind turbine blade 14 has a pair of oblique blades 14b extending from the rotating part 12 so that the distance between them increases with increasing distance from the vertical axis Z, and a main blade 14a extending along a direction parallel to the vertical axis Z. The wind turbine blade 14 is formed in a substantially triangular shape symmetrical with respect to the horizontal axis X in a side view. Note that the term "substantially triangular" as used here means that the overall shape of the wind turbine blade 14 is close to a triangle, and includes a triangle with curved corners or one with any of the three sides curved. The wind turbine blade 14 is formed with a streamlined blade cross section with a curved leading edge and a pointed trailing edge.

[0016] The over-rotation suppression mechanism 20 includes a movable part 21 for suppressing over-rotation, and an over-rotation suppression inductor 22 . The movable part 21 is provided on a part of the arm 13. The movable part 21 is rotatable around an arm shaft 13a that connects the rotating part 12 and the wind turbine blade 14. The over-rotation suppression inductor 22 is provided on the movable part 21. The over-rotation suppression inductor 22 tilts the movable part 21 around the arm axis 13a by the action of centrifugal force, aerodynamic force, and gravity generated when the wind turbine blade 14 rotates, and returns the movable part 21 to its initial state when the wind turbine blade 14 stops rotating. In this way, the over-rotation suppression mechanism 20 comprises a movable part 21 for suppressing over-rotation that can rotate around the axis of the arm shaft 13a connecting the rotating part 12 and the wind turbine blade 14, and an over-rotation suppression inductor 22 that is provided on the movable part 21 and tilts the movable part 21 around the arm shaft 13a by the action of centrifugal force, aerodynamic force, and gravity generated when the wind turbine blade 14 rotates, and returns the movable part 21 to its initial state when the wind turbine blade 14 stops rotating. Because the aerodynamic force acting on the movable part 21 prevents the vertical axis wind turbine 10 from rotating at or above the set rotation speed, it is possible to stop the power supply to the DC / AC converter 90 without requiring a braking resistor. In this embodiment, the movable part 21 and the over-rotation suppression guide 22 are formed with a blade cross section having the same shape as the wind turbine blade 14 , but may be formed with a blade cross section having a different shape from the wind turbine blade 14 .

[0017] FIG. 2(a) is a perspective view of the main part of the vertical axis wind turbine in a state where over-speed suppression is not performed, and FIG. 2(b) is a perspective view of the main part of the vertical axis wind turbine in a state where over-speed suppression is performed. As the wind speed increases and the wind turbine blades 14 reach a high rotation speed state, the rotational direction component F1 of the centrifugal force acting on the over-rotation suppression inductor 22 increases, and as the lifting moment due to the rotational direction component F1 of the centrifugal force acting on the over-rotation suppression inductor 22 increases, the inclination angle θ2 increases. By increasing the inclination angle θ2, the projected area of ​​the movable part 21 seen from the direction of rotation of the wind turbine becomes larger, and a large braking force F2 due to aerodynamic forces acts on the movable part 21, suppressing over-rotation of the wind turbine. In strong wind conditions, a large braking force is generated even at low rotation speeds. As a result, in strong wind conditions, the rotation speed of the wind turbine blades 14 is suppressed to a low speed.

[0018] FIG. 3(a) is a block diagram showing a vertical axis wind turbine power generating unit equipped with an over-rotation suppression mechanism according to this embodiment. The vertical axis wind turbine generating unit equipped with the over-rotation suppression mechanism according to this embodiment includes the vertical axis wind turbine 10 equipped with the over-rotation suppression mechanism 20, the speed increaser 30 for increasing the speed of the vertical axis wind turbine 10, the generator 40 for converting the rotational energy of the vertical axis wind turbine 10 into electrical energy, the rectifier 50 for converting the AC power output from the generator 40 into DC, the generator output detection means 60 for detecting the power output from the rectifier 50, an opening switch 70 disposed between the rectifier 50 and the DC / AC converter 90, and the PWM control means 80 for operating the generator 40 at a set operating point. Here, the vertical axis wind turbine 10 has vertical axis wind turbine characteristics for each wind speed (V0, V1, V2 shown in FIG. 3(b)). For example, in the characteristics at wind speed V2, the over-rotation suppression mechanism 20 operates at the rotation speed Nx, so the shaft torque decreases at this rotation speed Nx. The generator output detection means 60 is a means for detecting the power value obtained by multiplying the shaft torque and the rotation speed of the generator 40. If the power output from rectifier 50 is below the allowable input value of DC / AC converter 90, it is input to DC / AC converter 90, and when it reaches a predetermined value that exceeds the allowable input value of DC / AC converter 90, the power supply to DC / AC converter 90 is stopped. The generator output detection means 60 detects the power output from the rectifier 50, and when it detects a predetermined value, it opens the open switch 70 and stops the power supply to the DC / AC converter 90. In this way, the control unit can protect the DC / AC converter 90 by opening the open switch 70 when the generator output detection means 60 detects a predetermined value. The PWM control means 80 changes the pulse width of the PWM in accordance with the rotation speed of the generator 40. That is, when the rotation speed of the generator 40 is low, the pulse width at which the energizing current is turned ON is made small, and when the rotation speed of the generator 40 is high, the pulse width at which the energizing current is turned ON is made large, thereby changing the resistance value equivalent to the pulse width at which the energizing current is turned ON, such as R0, R1, and R2, and thereby changing the relationship between the load torque Q on the output side as seen from the generator 40 and the rotation speed N (R0>R1>R2). The load characteristics of the generator 40 are set by matching the rotation speed dependency of the load torque Q to the wind turbine characteristics. In this way, by setting a corresponding pulse width for each rotation speed, it is possible to set generator characteristics that match the characteristics of the wind turbine.

[0019] 4 is a graph for explaining a method for setting the generator characteristics in a vertical axis wind turbine equipped with an overspeed suppression mechanism according to an embodiment of the present invention. Note that in the following explanation, the no-load torque (drag torque) of the speed increaser 30 and the generator 40 is not taken into consideration. First, the operation start point of the over-rotation suppression mechanism is determined in consideration of the annual wind speed at the installation location so that the vertical axis wind turbine equipped with the over-rotation suppression mechanism according to this embodiment does not rotate at a speed greater than the set speed. For example, the annual occurrence rate of wind speed at a location with an annual average wind speed of about V = 3.7 m / s is expected as shown in Figure 4(a), but at a wind speed level of V = 8 m / s (7.5 m / s - 8.5 m / s), it is 2.33 % and at a wind speed level of V = 9 m / s (8.5 m / s - 9.5 m / s), it is 0.99 %. Thus, at a wind speed level of V = 9 m / s, the annual occurrence rate of wind speed is expected to be less than 1 %. By the way, at a wind speed level of V=5 m / s (4.5 m / s to 5.5 m / s), the occurrence rate is 13.67%, and at a wind speed level of V=4 m / s (3.5 m / s to 4.5 m / s), which shows the highest occurrence rate, the occurrence rate is 18.33%. Therefore, since the wind speed level (assuming 1 m / s intervals) at which the annual wind speed occurrence rate is 2% or more at a location with an annual average wind speed V=3.7 m / s is below the wind speed V=8 m / s level, the ideal operating point of wind speed V=8 m / s is selected as the operating point at the maximum rotation speed of the over-rotation suppression mechanism 20. Figure 4(b) shows the torque characteristics (pure torque of the wind turbine rotor only) generated by the wind turbine at wind speeds V = 5 m / s and V = 8 m / s. The ideal operating points (torque and revolutions per minute equivalent to maximum output) at these times are shown in the table in Figure 4(c). In addition, in FIG. 4(b), the sudden drop in the wind turbine shaft torque curve is due to the operation of the over-speed suppression mechanism 20. Similarly, by finding the ideal operating points in the range of wind speed V = 3 m / s to V = 8 m / s and finding the curve that approximates them, a quadratic expression of the revolutions per minute N can be obtained (Figure 4(d)).

[0020] Figure 5 is a graph showing the pure shaft torque characteristics of the wind turbine before subtracting the no-load torque and the approximation curve of the operating point (Figure 4(d)) in the wind speed range from V = 3 m / s to 16 m / s. In order to avoid complicating the diagram, torque curves for wind speeds V = 17 m / s or more are not drawn. However, in the assumed wind turbine, since the over-speed suppression mechanism 20 functions as shown in the range of wind speeds V = 9 m / s to V = 16 m / s, the torque curve at high wind speeds intersects with the operating curve at low rotation speeds, and it is expected that the turbine will operate at low rotation speeds. For example, if the rated output capacity of DC / AC converter 90 is 9.9 kW and the input tolerance of DC / AC converter 90 is 11 kW, then when the output from rectifier 50 exceeds 11 kW, generally, in order to protect DC / AC converter 90, the output destination of rectifier 50 is automatically switched to a braking resistor and no power is sent to DC / AC converter 90. However, in this embodiment, since the overspeed suppression mechanism 20 functions, when the output of the generator 40 exceeds the allowable value of 11 kW, even in the maximum operating point state shown in FIG. 5 (wind speed V=8 m / s, wind turbine rotation speed N=44 rpm), there is no need to apply the electric brake with the brake resistor to decelerate the wind turbine. In this case, the rectifier 50 does not pass the power from the generator 40 to the brake resistor, but opens the output terminal of the generator 40 to stop the current from flowing. In other words, the generator 40 is in an unloaded state, and accelerates and increases the rotation speed, but the overspeed suppression mechanism 20 works, and the aerodynamic brake (aerodynamic brake) operates, and the wind turbine operates at the rotation speed (ultimate rotation speed) where the torque curve for each wind speed in FIG. 5 intersects with the horizontal axis. In other words, for example, the wind turbine operates at 45 rpm when the wind speed V=8 m / s, 46 rpm when the wind speed V=7 m / s, and 44 rpm when the wind speed V=9 m / s, so there is no structural impact on the wind turbine. That is, the braking resistor can be omitted, and the cost of the wind turbine system can be reduced.

[0021] FIG. 6 is a graph in which a torque curve t corresponding to the allowable value of the DC / AC converter and a straight line s indicating the allowable maximum rotation speed of the generator are added to the graph shown in FIG. The curve t shown in Fig. 6, which is drawn as a setting limit of the PWM control and the DC / AC converter, is a torque curve equivalent to the allowable value of the PWM control and the DC / AC converter, and any torque higher than this curve exceeds the allowable value of the PWM control and the DC / AC converter. The curve t is obtained by multiplying the shaft torque and the rotation speed of the vertical axis wind turbine 10. Also, the straight line s shown in Fig. 6 as the power generation voltage limit speed is the maximum allowable speed of the wind turbine, which corresponds to the maximum allowable speed of the generator 40, and here the maximum allowable speed of the wind turbine is set to 33 rpm. From this, it can be said that it is desirable for the vertical axis wind turbine power generating unit to operate in the overlapping range of the area below the curve t (arrow direction) and the area to the left of the straight line s (arrow direction). In other words, if there is an operating point in this overlapping range, the generator output detection means 60 will not operate the open switch 70, and the over-speed suppression mechanism 20 will not control the rotation in the wind speed range of 16 m / s or less shown in Fig. 6.

[0022] FIG. 7 is a graph showing an embodiment of a method for setting an operating point in PWM control. In Fig. 7, up to the wind turbine rotation speed N = 30 rpm, the torque is set to be approximately the same as the ideal operating point shown in Fig. 5, and in the range of wind turbine rotation speed N = 30 to 32 rpm, the load torque of the generator 40 is set to increase rapidly, and above the wind turbine rotation speed N = 32 rpm, the torque characteristics are set to be equivalent to the allowable value of the DC / AC converter shown in Fig. 6. In Fig. 7, the operating point set in this way is referred to as operating point 1.

[0023] FIG. 8 shows the wind turbine rotation speed and shaft torque characteristics of the wind turbine, and the power curve of the wind turbine, predicted when the operating points are set as shown in FIG. Figure 8(a) shows the wind turbine rotation speed and shaft torque characteristics for the wind speed V (2 to 60 m / s) predicted when the operating point is set as shown in Figure 7, and Figure 8(b) shows the wind turbine power curve predicted when the operating point is set as shown in Figure 7. The predicted annual power generation is 21,227 kWh (after taking into account losses in the PWM control and DC / AC converter) at an average wind speed of 3.7 m / s. When the operating point is set as shown in Figure 7, at rotation speed N = 32 rpm, the operating point torque is larger than the wind turbine shaft torque predicted for all wind speeds up to V = 60 m / s. Therefore, theoretically, it is predicted that the wind turbine rotation speed N will not exceed 32 rpm (see Figure 8(a)). However, as shown in Figures 8(a) and 8(b), the rotation speed drops sharply and the output drops when the wind speed is in the range of V = 13 to 17 m / s. This is because the rotational torque of the wind turbine is smaller in the wind speed range of V = 13 to 17 m / s than the torque at the operating point shown in Figure 7. The predictions made here are based on the assumption of a steady state, and so in terms of time behavior, once the rotation speed drops significantly, if the moment of inertia of the wind turbine is large, it takes time for the rotation speed to increase again, and so the drop in rotation speed in the wind speed range V = 13 to 17 m / s as shown in Figures 8(a) and 8(b) is undesirable.

[0024] FIG. 9 is a graph showing another embodiment of the method for setting an operating point in PWM control. 7, the rotation speed can be limited to below the limit value of the generator 40, but a drop in the rotation speed is expected in the wind speed range of V = 13 to 17 m / s. Also, at the rotation speed N = about 32 rpm, the operating point is set to be greater than the wind turbine torque, but the margin is not large, so it is preferable to increase the margin. Therefore, up to the wind turbine rotation speed N = 24 rpm, the torque is set to be approximately the same as the ideal operating point shown in Fig. 5, in the range of wind turbine rotation speed N = 25 to 28 rpm, the torque is set to be smaller than operating point 1 shown in Fig. 7, and the torque increase rate is set to be smaller, in the range of wind turbine rotation speed N = 28 to 32 rpm, the load torque of the generator 40 is increased rapidly, and above the wind turbine rotation speed N = 32 rpm, the torque characteristics are set to be equivalent to the allowable value of the DC / AC converter shown in Fig. 6. Note that in Fig. 9, the operating point set in this way is designated as operating point 2.

[0025] FIG. 10 shows the wind turbine rotation speed and wind turbine shaft torque characteristics, and the wind turbine power curve, predicted when the operating points are set as shown in FIG. Figure 10(a) shows the wind turbine rotation speed and shaft torque characteristics for the wind speed V (2 to 60 m / s) predicted when the operating point is set as shown in Figure 9, and Figure 10(b) shows the wind turbine power curve predicted when the operating point is set as shown in Figure 9. The predicted annual power generation is 19,746 kWh (after taking into account losses in the DC / AC converter) at an average wind speed of 3.7 m / s. The annual power generation amount is estimated to be lower at operating point 2 in Fig. 9 compared to operating point 1 in Fig. 7, but as shown in Fig. 10(a), there is no sudden decrease in the rotation speed in the wind speed range V = 13 to 17 m / s, and it is expected to remain constant at around rotation speed N = 28 rpm. Also, as shown in Fig. 10(a) and Fig. 10(b), the decrease in torque and output is smaller compared to operating point 1, and the wind turbine behavior is expected to be stable.

[0026] FIG. 11 is a graph showing a comparison between the operating points shown in FIG. 7 and the operating points shown in FIG. For reference, the torque curves of the wind turbine for wind speeds V=8m / s and V=15m / s are shown. By installing the over-speed suppression mechanism 20, it is possible to eliminate the need for an electric brake resistor. However, if it is necessary to limit the rotation speed due to an upper limit on the rotation speed of the generator 40, it is desirable to set the operating point so that it is greater than the net rotational torque of the wind turbine at all wind speeds, near the upper limit rotation speed, as shown by A in Figure 11. Furthermore, if a sudden drop in the rotation speed is observed in the medium wind speed region slightly exceeding the rated wind speed (V = 8 m / s in this example), it is desirable to change the torque at the operating point to a slightly smaller value, as shown in B in FIG. 11. Furthermore, since increasing the margin above or below the operating point at A and B in Figure 11 from the wind turbine torque increases the reliability of expected operation, it is desirable to set the operating point so that the margin is large within a range where the efficiency of the wind turbine (or annual power generation) is not significantly reduced. Furthermore, since a large rate of increase in torque with respect to the rotation speed between A and B in FIG. 11 is not preferable for control devices such as the DC / AC converter 90, it is desirable to reduce the rate of increase in torque with respect to the rotation speed between A and B (make the slope gentler), as in the correction from operating point 1 to operating point 2 shown in FIG. 11. [Industrial Applicability]

[0027] According to the control method for a vertical axis wind turbine generating unit equipped with an over-rotation suppression mechanism of the present invention, it is possible to stop the power supply to the DC / AC converter without requiring a braking resistor. [Explanation of symbols]

[0028] 10 Vertical axis wind turbine 11 Base 11a Legs 11b Storage section 12 Rotating section 13 Arm 13a Arm axis 14 Windmill blade 14a Main wing 14b oblique wing 20. Overspeed prevention mechanism 21 Moving parts 22 Hyperrotation suppression derivatives 30 Speed ​​increaser 40 Generator 50 rectifier 60 Generator output detection means 70 Open Switch 80 PWM control means 90 DC / AC Converter X horizontal axis

Claims

1. A vertical axis wind turbine equipped with an over-rotation suppression mechanism; a generator that converts the rotational energy of the vertical axis wind turbine into electrical energy; a rectifier that converts the AC power output from the generator into DC power; Equipped with The power output from the rectifier is input to a DC / AC converter. A vertical axis wind turbine generating unit equipped with an over-rotation suppression mechanism, a generator output detection means for detecting the electric power output from the rectifier; an opening switch disposed between the rectifier and the DC / AC converter; having The control unit opens the open switch to stop the power supply to the DC / AC converter when the generator output detection means detects a predetermined value. A vertical axis wind turbine generating unit equipped with an over-rotation suppression mechanism characterized by the above.

2. The vertical axis wind turbine comprises: a base having the generator; A rotating part that rotates about a vertical axis relative to the base part; a plurality of wind turbine blades connected to the rotating portion via arms and rotating around the vertical axis; Equipped with The over-rotation suppression mechanism, a movable part for suppressing over-rotation, the movable part being provided on the arm and rotatable around an arm axis connecting the rotating part and the wind turbine blade; an over-rotation suppression inductor that is provided in the movable part, tilts the movable part around the arm axis by the action of centrifugal force, aerodynamic force, and gravity generated when the wind turbine blade rotates, and returns the movable part to its initial state when the wind turbine blade stops rotating; Equipped with The vertical axis wind turbine does not rotate at a set rotation speed or higher due to the aerodynamic force acting on the moving part. A vertical axis wind turbine power generating unit equipped with the over-rotation suppression mechanism according to claim 1.

3. The generator is PWM controlled so as to operate at a preset operating point. A vertical axis wind turbine power generating unit equipped with the over-rotation suppression mechanism according to claim 1.

4. A vertical axis wind turbine equipped with an over-rotation suppression mechanism; a generator that converts the rotational energy of the vertical axis wind turbine into electrical energy; a rectifier that converts the AC power output from the generator into DC power; Equipped with The power output from the rectifier is input to a DC / AC converter. A method for controlling a vertical axis wind turbine generating unit equipped with an over-rotation suppression mechanism, comprising the steps of: a generator output detection means for detecting the electric power output from the rectifier; an opening switch disposed between the rectifier and the DC / AC converter; having When the generator output detection means detects a predetermined value, the open switch is opened to stop the power supply to the DC / AC converter. A method for controlling a vertical axis wind turbine generating unit equipped with an over-rotation suppression mechanism, comprising:

5. The vertical axis wind turbine comprises: a base having the generator; A rotating part that rotates about a vertical axis relative to the base part; a plurality of wind turbine blades connected to the rotating portion via arms and rotating around the vertical axis; Equipped with The over-rotation suppression mechanism, a movable part for suppressing over-rotation, the movable part being provided on the arm and rotatable around an arm axis connecting the rotating part and the wind turbine blade; an over-rotation suppression inductor that is provided in the movable part, tilts the movable part around the arm axis by the action of centrifugal force, aerodynamic force, and gravity generated when the wind turbine blade rotates, and returns the movable part to its initial state when the wind turbine blade stops rotating; Equipped with The vertical axis wind turbine does not rotate at a set rotation speed or higher due to the aerodynamic force acting on the moving part. A method for controlling a vertical axis wind turbine generating unit having an over-rotation suppression mechanism according to claim 4.

6. The generator is PWM controlled so as to operate at a preset operating point. A method for controlling a vertical axis wind turbine generating unit having an over-rotation suppression mechanism according to claim 4.

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