JP2015162976A - wind power generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wind power generation method capable of reaching an optimum revolution speed in a short time while reducing load search time of a wind power generator.SOLUTION: A wind power generator determines the power generation amount by a power generator which uses a wind of a certain wind speed by measuring at least one of values of temperature, humidity and atmospheric pressure with detection units 104, 105 and 106; and determining an electrical load on an electrical load unit 103 with an electrical load determination unit 90 using the values measured by the detection unit. The electrical load unit which has the determined electrical load is connected to a power generator 102 to generate electric power.

Description

  The present invention relates to a wind power generation method.

  As clean and inexhaustible energy sources, solar power, wind power, and hydropower are attracting attention. With solar power and wind power, large-scale power plants have been constructed, and commercial power generation has started. Among them, wind power generation has a relatively low power generation cost, and can convert wind energy into electric energy with high efficiency. However, the wind speed and direction of natural wind constantly change, and the wind may cease for a long time, making it difficult to ensure a stable power generation amount. From such a background, a wind power generator (for example, Patent Document 1) using exhaust air from a forced ventilation place that can always ensure a constant wind speed, or both exhaust air and natural wind from a cooling tower are used. A wind power generator (for example, Patent Document 2 or Patent Document 3) has been proposed.

  FIG. 5 shows a general wind power generator. An electrical load unit 2103 is connected to a generator 2102 connected to the windmill 2101. In FIG. 5, the windmill 2101 rotates by receiving wind, and the generator 2102 converts the rotational energy into electric energy. At this time, when the electric load in the electric load unit 2103 connected to the generator 2102 is changed to increase or decrease the load current, a curve as shown in FIG. 6 can be drawn. It can be seen from FIG. 6 that there is an optimum load current for obtaining the maximum power generation amount.

  On the other hand, the power generation amount W of the wind power generation is expressed by the energy recovery efficiency Cp of the windmill, the air density ρ, the wind receiving area S, and the wind speed V as shown in Expression (1).

  In addition to the energy recovery efficiency Cp and the wind receiving area S, in the case of the exhaust wind, the wind speed V can be considered constant, but the air density ρ changes. Therefore, the curve 301 shown in FIG. 6 changes depending on the density ρ, and as shown in FIG. 7, it can be seen that the optimum load current also changes depending on the density ρ of air. More specifically, when the density ρ = ρ1, ρ2, and ρ3, curves 301a, 301b, and 301c are drawn, respectively. That is, even if the wind speed of the exhaust wind is constant, the maximum power generation amount cannot be obtained if the electrical load portion 2103 having a constant electrical load is always connected.

  From the above, in order to secure the maximum power generation amount, it is necessary to determine an optimal electrical load in the electrical load unit 2103 connected to the generator 2102 in accordance with the density ρ.

  Thus, generally, an MPPT method (Maximum Power Point Tracking) is employed as a method of determining an electrical load in the electrical load unit 2103 (see, for example, Patent Document 4).

  Hereinafter, the MPPT method will be described in detail with reference to FIGS.

  FIG. 8 shows a flowchart of a general MPPT method, which is also called “mountain climbing method”. Assuming that the power generation amount W0 and the load current I0 are at the start of control, the power generation amount W is obtained by changing the load current I by ΔI. If W> W0, the power generation amount W is obtained by changing the load current I by ΔI without changing the sign of ΔI. In the case of W <W0, the sign of ΔI is inverted and the load current I is changed by ΔI to obtain the power generation amount W. By repeating these steps, it is possible to search for a load current that can obtain the maximum power generation amount, which is indicated by a black circle 302 in FIG. Further, as described above, since the maximum value of the power generation amount varies depending on the density ρ, it is necessary to repeat the search every time the density ρ changes.

JP-A-64-87878 JP 2007-00583 A JP 2013-40610 A JP 2003-167603 A

  However, the MPPT method is feedback control that compares the power generation amount before and after changing the load current and searches for the optimal electrical load state so that the maximum power generation amount can be obtained, and it takes time until the optimal electrical load is found. There is a problem that it takes.

  This invention is made | formed in view of the said reason, The objective is to provide the wind power generation method which can determine the optimal electric load for obtaining the maximum electric power generation amount in a short time. .

  In order to achieve the above object, the present invention is configured as follows.

In order to achieve the above object, a wind power generation method according to an aspect of the present invention includes a windmill, a generator connected to the windmill, and a power generation amount of the generator that is connected to the generator. A wind power generation method in a wind turbine generator comprising an electrical load,
Measure at least one of temperature, humidity and atmospheric pressure with the detector,
An electrical load in the electrical load unit is determined by an electrical load determination unit using a value measured by the detection unit, and the electrical load unit having the determined electrical load is connected to the generator. The power generation amount of the generator is determined by generating power with the generator.

Further, in the wind power generation method according to another aspect of the present invention, in the first power generation after the installation of the wind power generation device, the electrical load determination unit performs the maximum power generation amount in the electrical load unit. The electrical load is changed to determine the electrical load, and at the same time, at least one of the temperature, humidity, and atmospheric pressure is measured by a detection unit,
After the installation of the wind power generator, for the second and subsequent power generation, among the temperature, humidity and atmospheric pressure, the same item as the first power generation is measured by the detection unit,
The electrical load determination unit determines the electrical load in the electrical load unit based on the value measured during the second and subsequent power generations and the value measured before that.

Further, in the wind power generation method according to another aspect of the present invention, the rotation of the generator is started without connecting the electric load unit to the wind power generator,
The electric load unit is connected to the generator from a predetermined rotational speed of the generator, and power generation is started.

  Furthermore, the wind power generation method according to another aspect of the present invention is capable of switching between connection and disconnection between the generator and the electrical load unit by a switch unit, and the switch unit allows the generator to be connected to the generator. The rotation of the generator is started without connecting an electric load, and the rotation speed is ½ or more of the convergence rotation speed of the generator that converges when the generator and the electric load are connected. After reaching, the switch unit connects the electrical load unit to the generator to start power generation.

  According to the aspect of the present invention, since feedforward control is performed by estimating and determining an optimal electrical load from at least one value of temperature, humidity, and atmospheric pressure, only conventional feedback control is performed. Compared to the case, the time required to search for an optimal electrical load can be greatly shortened, which contributes to an increase in the amount of power generation.

It is a figure for demonstrating the wind power generation method in 1st Embodiment of this invention. It is a figure for demonstrating the wind power generator in 1st Embodiment of this invention. It is a figure for demonstrating the peripheral speed ratio and energy recovery efficiency of a wind power generator. It is a figure for demonstrating the timing which connects a generator and an electrical load part. It is a figure for demonstrating the timing which connects a generator and an electrical load part. It is a figure for demonstrating the timing which connects a generator and an electrical load part. It is a figure for demonstrating the timing which connects a generator and an electrical load part. It is a figure for demonstrating the conventional wind power generator. It is a figure for demonstrating the relationship between load current and electric power generation amount. It is a figure for demonstrating the relationship between a load current, the electric power generation amount, and the density of air. It is a figure for demonstrating the flowchart of MPPT method. It is a figure for demonstrating the method of searching for the load electric current in which the electric power generation amount becomes the maximum by MPPT method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
A wind power generation method according to the first embodiment of the present invention will be described. FIG. 1 is a flowchart for explaining a wind power generation method according to the first embodiment of the present invention. FIG. 2 is a diagram for explaining the wind turbine generator 100 according to the first embodiment of the present invention.

  As shown in FIG. 2, in the wind turbine generator 100, an electrical load unit 103 is connected to a generator 102 connected to a windmill 101 via a switch unit 80. The electric load at 103 is determined to determine the amount of power generated by the generator 102. When the windmill 101 receives wind and rotates, the generator 102 converts the rotational energy into electrical energy. At this time, the load current is increased / decreased by changing the electrical load in the electrical load unit 103 connected to the generator 102, thereby causing the optimum load current to flow through the generator 102. For example, as shown in FIG. Based on such a curve 301 between the power generation amount and the load current, the generator 102 can obtain the maximum power generation amount. The generator 102 includes a motor 102M and a rotation speed detector 95 such as an encoder or a frequency detection sensor disposed adjacent to the motor 102M.

  An example of the electrical load unit 103 is a device that switches connection of a plurality of resistors having different resistance values, a variable resistor, or the like.

  The electrical load determination unit 90 determines the amount of power generated by the generator 102 by determining the optimal electrical load in the electrical load unit 103.

  The switch unit 80 performs connection or disconnection between the generator 102 and the electrical load unit 103 at a predetermined timing.

  As described above, the amount of power generated by wind power generation is expressed by Equation (1). In addition to the energy recovery efficiency Cp and the wind receiving area S, in the case of exhaust air, the wind speed V can also be considered constant, but the air density ρ varies depending on the surrounding environment. Therefore, it is necessary to search for an optimal electrical load in the electrical load unit 103 in accordance with the air density ρ. Here, the density ρ of air is expressed by Equation (2) using the temperature T, the humidity RH, and the atmospheric pressure P. From the equations (1) and (2), the maximum power generation amount when the electric load unit 103 having the optimum electric load is connected to the generator 102 can be calculated by the electric load determination unit 90 as described later. .

  Next, a method for predicting and determining the optimum electrical load in the electrical load unit 103 by the electrical load determination unit 90 will be described with reference to the flowchart of FIG. As shown in FIG. 2, the wind turbine generator 100 includes an electrical load determination unit 90 between the generator 102 and the electrical load unit 103, and further includes a temperature detection unit 104 and humidity as an example of the detection unit. The detection unit 105 and the atmospheric pressure detection unit 106 are connected to the electrical load determination unit 90. The electrical load determination unit 90 includes a search unit 91, a calculation unit 92, and a storage unit 93. Therefore, the temperature detection unit 104, the humidity detection unit 105, and the atmospheric pressure detection unit 106 are connected to at least the calculation unit 92 and the storage unit 93 of the electrical load determination unit 90.

  In the flowchart of FIG. 1, the operation step S1 during the first operation after the installation of the wind turbine generator is roughly divided into the operation step S2 during the operation after the installation of the wind turbine generator. The operation step S1 includes step S11 for obtaining an optimal electrical load by feedback control, step S12 for measuring temperature, step S13 for measuring humidity, step S14 for measuring atmospheric pressure, and step S15 for obtaining air density. It consists of and. The operation step S2 includes a step S21 for measuring the temperature, a step S22 for measuring the humidity, a step S23 for measuring the atmospheric pressure, a step S24 for obtaining the density of the air, and a step S25 for determining the electric load. Has been. As an example, whether the operation is performed for the first time or after the second operation, if the rotation speed detector 95 can detect a rotation speed equal to or higher than a predetermined rotation speed, it is determined that the generator 102 has been operated, By storing the situation in the storage unit 93, it is possible to determine the number of operations.

  First, after the installation of the wind power generator 100, the search unit 91 searches for the optimal electrical load Z0 by the same feedback control S11 such as the MPPT method as before when the first operation (during power generation). That is, an optimum electrical load Z0 is obtained by the search unit 91 by a method according to the flowchart of FIG. 8, and the power generation amount at that time is set as W0 by the search unit 91. At the same time, the temperature T0, the humidity RH0, and the atmospheric pressure P0 are measured by the temperature detection unit 104, the humidity detection unit 105, and the atmospheric pressure detection unit 106 in steps S12 to S14 of the operation step S1, and the equation (2) is calculated from these values. In step S15 of the operation step S1, the calculation unit 92 obtains the air density ρ0. The optimum electrical load value obtained in step S11, the values measured by the temperature detection unit 104, the humidity detection unit 105, and the atmospheric pressure detection unit 106 in steps S12 to S14, and the air density obtained in step S15 are stored in the storage unit. 93 respectively.

  Next, after the installation of the wind power generation apparatus 100, at the second and subsequent power generations, the temperature detected by the temperature detection unit 104, the humidity detection unit 105, and the atmospheric pressure detection unit 106 and stored in the storage unit 93 before that Using the values of T0, humidity RH0, atmospheric pressure P0, and electrical load Z0, a predictive optimum electrical load Z1 is obtained by the calculation unit 92. At this time, at least, among the temperature, humidity, and atmospheric pressure, the same item as the first power generation is measured by the corresponding detection unit among the temperature detection unit 104, the humidity detection unit 105, and the atmospheric pressure detection unit 106, The calculation unit 92 obtains a predictive optimum electrical load.

  Specifically, as described in steps S21 to S23 of the flowchart S2 in FIG. 1, the temperature detection unit 104, the humidity detection unit 105, and the atmospheric pressure detection unit 106 measure the temperature T1, the humidity RH1, and the atmospheric pressure P1.

  Next, in step S24 of the flowchart S2 in FIG. 1, the calculation unit 92 obtains the air density ρ1 from these measured values using Equation (2). The maximum power generation amount W1 is expressed by Equation 92 from Equation (1) using Equation ρ0 and ρ1.

  Between the power generation amount W0 and the voltage V0 at that time, and the power generation amount W1 and the voltage V1 at that time, there is a relationship of Expression (4) and Expression (5).

  Here, the energy recovery efficiency of the windmill 101 is demonstrated using FIG. According to FIG. 3, it can be seen that the energy recovery efficiency Cp of the windmill 101 changes depending on the peripheral speed ratio that is the ratio between the wind speed and the rotational speed of the windmill 101. Also, the difference in the curve is due to the type of the windmill 101, the curve 201 indicates the ideal efficiency of the propeller type windmill, and the curve 202 indicates the efficiency of the three-blade propeller type. In the case of the curve 202, the efficiency reaches a maximum of about 0.45 at a peripheral speed ratio of about 6. That is, in order to generate electric power with high efficiency, it is necessary to make the rotation speed of the motor 102M of the generator 102 constant so that the peripheral speed ratio at which the energy recovery efficiency Cp of the wind turbine 101 is maximized is about 6.

  On the other hand, from the characteristics of the generator 102, if the rotation speed of the motor 102M of the generator 102 is constant, the output voltage V is also constant, so V1 = V0, and the optimum electrical load Z1 is shown in FIG. In step S25 of the flowchart S2, the calculation unit 92 obtains the equation (6) from the equations (4) and (5).

  Thus, the electrical load determination unit 90 can predict and determine the optimal electrical load in the electrical load unit 103 in advance by using the temperature, humidity, and atmospheric pressure. Thereby, compared with the case of only the conventional feedback control, it is possible to find the optimum electrical load in the electrical load unit 103 in a short time, and thus it is possible to increase the amount of power generation.

  Note that it is not necessary to use all values of temperature, humidity, and atmospheric pressure in order to predict and determine the electrical load in the electrical load unit 103 by the electrical load determination unit 90. For example, the temperature changes almost. In such an environment, only the values of humidity and pressure other than temperature need be used. In this way, depending on the installation environment, only a necessary value (in other words, at least one value of temperature, humidity, and atmospheric pressure) is used from among these temperatures, humidity, and atmospheric pressure. The load determination unit 90 may predict and determine the electrical load in the electrical load unit 103.

  Next, the timing at which the generator 102 and the electrical load unit 103 are connected by the switch unit 80 will be described. When the generator 102 is connected to the electrical load unit 103, a load current flows due to the electromotive force generated by the rotation. When the load current flows, a force is generated in a direction that hinders rotation, which becomes a resistance to increase in the rotation speed of the motor 102M of the generator 102. The generator 102 requires the largest torque when starting to rotate from the stopped state of the motor 102M. Therefore, immediately after the rotation of the motor 102M is started (for example, until the rotational speed measured by the rotational speed detector 95 reaches the first predetermined rotational speed), the switch 102 causes the generator 102 to be connected to the electrical load section. The switch unit 80 is connected to the switch unit 80 after the rotational speed is increased to a certain level in a no-load state (for example, after the rotational speed measured by the rotational speed detector 95 reaches the second predetermined rotational speed). Thus, the generator 102 is connected to the electrical load unit 103. By comprising in this way, it can be brought close to the peripheral speed ratio in which efficient power generation is possible, and the power generation amount can be improved. However, it is set as 1st predetermined rotation speed <2nd predetermined rotation speed.

  As an example, the case where the wind power generator 100 is installed in a cooling tower is demonstrated.

  First, the rotation speed that converges when the generator 102 and the electrical load section 103 are connected by the switch section 80 is defined as the convergence rotation speed. As shown in FIG. 3, the convergence rotational speed is always constant when the peripheral speed ratio at which the energy recovery efficiency Cp of the wind turbine 101 is maximum is around 6 and the wind speed is constant. However, since the time to reach the convergence speed depends on the density ρ of the air, it varies depending on the temperature, atmospheric pressure, and humidity. It is possible to control the convergence speed. As an example of the case where the convergence rotational speed is adjusted to be around 200 rpm, the integrated power generation amount when the rotational speed of the motor 102M of the generator 102 when connecting to the electrical load unit 103 is changed is shown in FIG. Shown in The power generation amount is a value obtained by integrating the outputs of the power generator 102 when 300 seconds have elapsed after the fan of the cooling tower is operated. As is clear from FIG. 4A, the motor 102M of the generator 102 is in a no-load state compared to when it is connected to the electrical load unit 103 since the blower (in other words, the generator 102) is stopped. One that is connected to the electrical load unit 103 after the rotation is started and the number of revolutions of the motor 102M is increased to some extent (for example, after the number of revolutions measured by the revolution number detector 95 reaches the second predetermined number of revolutions). However, it can be seen that the integrated power generation amount increases.

  Further, FIGS. 4B, 4C, and 4D show the connection rotation speed to the electrical load unit 103 as an example when the convergence rotation speed is adjusted to be around 250 rpm, 330 rpm, and 400 rpm, respectively. This is the integrated power generation when changed. Here, the connection rotational speed is the rotational speed of the motor 102 </ b> M of the generator 102 when the generator 102 is connected to the electrical load unit 103 via the switch unit 80. 4C and 4D are similar to FIG. 4A in that the generator 102 is in a no-load state than when the blower (in other words, the generator 102) is stopped and connected to the electrical load unit 103. The rotation of the motor 102M is started and the number of rotations of the motor 102M increases to a certain level (for example, after the number of rotations measured by the rotation number detector 95 reaches the second predetermined number of rotations) (more specifically, In FIG. 4B, the integrated power generation amount is larger when the electric load unit 103 is connected (after the vicinity of 100 rpm in FIG. 4C and the vicinity of 50 rpm in FIG. 4C). However, in FIG. 4B, it can be seen that when the electric load unit 103 is connected at 50 rpm, the integrated power generation amount is smaller than when the electric load unit 103 is connected from the beginning. This is probably because the cooling tower is installed outdoors, so that disturbances such as natural winds affect the rotation of the windmill 101. From FIG. 4A to FIG. 4C, even when there is an influence of disturbance, the connection rotational speed that can increase the integrated power generation amount compared to the case where the electrical load unit 103 is connected from the beginning is the convergence rotational speed. It turned out that it was 1/2 or more of. Therefore, even when there is an influence of disturbance, when it is desired to increase the integrated power generation amount as compared with the case where it is connected to the electrical load unit 103 from the beginning, 1 / of the convergence rotational speed of the motor 102M of the generator 102 is obtained. After assuming that the motor 102M has reached a rotational speed of 2 or more (for example, after the rotational speed measured by the rotational speed detector 95 reaches the third predetermined rotational speed), the switch section 80 causes the electrical load section to The power generation may be started by connecting 103 to the generator 102. However, the first predetermined rotation speed <the second predetermined rotation speed <the third predetermined rotation speed.

  As described above, according to the wind power generation method according to the first embodiment of the present invention, the electrical load determination unit 90 can predict and determine the optimal electrical load unit 103 in advance, and Contributes to improvement. In other words, since it is feedforward control that predicts and determines the optimal electrical load from at least one value of temperature, humidity, and atmospheric pressure, compared with the case of only conventional feedback control, The time required to search for an optimal electrical load can be greatly shortened, contributing to an increase in power generation. In addition, the amount of power generation is further improved by connecting the generator 102 to the electrical load unit 103 after reaching a certain number of revolutions, instead of connecting the generator 102 to the electrical load unit 103 from a stopped state. . Further, by connecting the generator 102 to the electrical load unit 103 after the convergence rotational speed becomes ½ or more, even if the generator 102 is affected by a disturbance, the generator 102 is connected to the electrical load unit 103 from the beginning. Compared to the case of connection, a large amount of power generation can be secured.

  In addition, it can be made to show the effect which each has by combining arbitrary embodiment or modification of the said various embodiment or modification suitably.

  The wind power generation method of the present invention is feedforward control that estimates and determines an optimal electrical load from at least one of temperature, humidity, and atmospheric pressure, and therefore searches for the optimal electrical load. Can significantly reduce the time it takes to increase the amount of power generated, and not only increase the amount of power generated by the wind power generator from exhaust air from a forced ventilation location or cooling tower, but also at any constant wind speed. It can be applied to wind power generators in places where wind blows.

DESCRIPTION OF SYMBOLS 90 Electric load determination part 91 Search part 92 Calculation part 93 Memory | storage part 95 Speed detector 100 Wind power generator 101 Windmill 102 Generator 102M Generator motor 103 Electric load part 104 Temperature detection part 105 Humidity detection part 106 Atmospheric pressure detection Part 201 Ideal efficiency 202 of propeller type wind turbine Efficiency curve 301 of three-blade propeller type wind turbine 301 Power generation amount 301a for load current Power generation amount 301b for load current when ρ = ρ1 Power generation amount 301c ρ for load current when ρ = ρ2 = Power generation amount S1 with respect to load current when ρ3 First flowchart after installation S2 Second and subsequent flowcharts after installation

Claims (4)

A wind power generation method in a wind turbine generator comprising a windmill, a generator connected to the windmill, and an electrical load unit that is connected to the generator and determines a power generation amount of the generator,
Measure at least one of temperature, humidity and atmospheric pressure with the detector,
An electrical load in the electrical load unit is determined by an electrical load determination unit using a value measured by the detection unit, and the electrical load unit having the determined electrical load is connected to the generator. A wind power generation method for determining a power generation amount of the power generator by generating power with the power generator. After the wind power generator is installed, in the first power generation, the electrical load is determined by changing the electrical load in the electrical load unit in the electrical load determination unit so that the amount of power generation is maximized. At the same time, at least one of the temperature, humidity, and pressure is measured by the detection unit,
After the installation of the wind power generator, for the second and subsequent power generation, among the temperature, humidity and atmospheric pressure, the same item as the first power generation is measured by the detection unit,
2. The electrical load determination unit determines the electrical load in the electrical load unit based on the value measured during the second and subsequent power generations and the value measured before that. Wind power generation method as described in 2. Without connecting the electrical load unit to the wind power generator, start rotating the generator,
The wind power generation method according to claim 1 or 2, wherein the electric load unit is connected to the generator from a predetermined rotational speed of the generator to start power generation.   Connection and disconnection between the generator and the electrical load unit can be switched by a switch unit, and the switch unit can rotate the generator without connecting the electrical load unit to the generator. After starting and reaching a rotational speed of 1/2 or more of the convergence rotational speed of the generator that converges when the generator and the electrical load section are connected, the electrical load section is switched by the switch section. The wind power generation method according to any one of claims 1 to 3, wherein the power generation is started by connecting to the generator.

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