JP2017204934A - Power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generator capable of exchanging energy of wind into electric energy more widely.SOLUTION: Regeneration mode of a power generator includes a first regeneration mode and a second regeneration mode (high efficiency regeneration mode) performed in high efficiency range where the peripheral velocity ratio λ of a vertical axis windmill 20 contains maximum output factor Cpmax thereof, and a third regeneration mode (low efficiency regeneration mode) performed in low efficiency range not containing the maximum output factor Cpmax. When the moving average wind velocity Vgr is equal to or above a third regeneration mode start reference value Vd (low efficiency discrimination threshold), the controller 80 controls an AC generator 30 in low efficiency regeneration mode via an inverter 40, and when the moving average wind velocity Vgr is less than the third regeneration mode start reference value Vd (low efficiency discrimination threshold), the controller 80 controls the AC generator 30 in high efficiency regeneration mode via the inverter 40.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power generator.

  As a power generator using natural energy (renewable energy), for example, a wind power generator is known. The wind power generator uses natural wind, but it is difficult to always keep the wind power in a certain range. That is, in the wind turbine generator, the fluctuation of the wind speed is very large compared with the fluctuation of the gas flow rate in the thermal power generation and the fluctuation of the water amount in the hydroelectric power generation, and the generated power fluctuates greatly.

  Conventionally, when the wind power is smaller than the drag torque of the windmill, when the windmill is stopped and then restarted, a large wind power exceeding the starting torque is required, and there is a problem that power generation cannot be performed accordingly.

  In order to solve the above problem, the technique of Patent Document 1 has been proposed. In Patent Document 1, at the time of start-up or when the rotation speed of the generator is detected and the rotation speed becomes equal to or less than a predetermined value, the power generator is operated to maintain the rotation speed of the generator at a predetermined value or more. I am doing so. In Patent Document 1, a power running operation of an alternator is performed at the time of start-up or in order to prevent the wind from weakening and the windmill blades (moving blades) from stopping. However, simply performing power running cannot be said to be optimal control of an optimal alternator. For various patterns of capricious fluids, such as wind, the relationship between the state of such fluids and the capacity of the fluid machine, the appropriate power running, switching timing of regeneration, less loss, more effective fluid flow It is desirable to exchange energy for generated energy.

  In addition, as a power generation device using natural energy (renewable energy), there are a hydroelectric power generation device, a sea current power generation device, a tidal current power generation device, a geothermal power generation device, etc. in addition to a wind power generation device, for example. Efficient operation is desirable.

  In order to solve the above-described efficient operation, the power generation device of Patent Document 2 is proposed in the present application. In Patent Document 2, in the first regeneration mode, the controller of the wind turbine generator starts the control of the generated current in proportion to the flow velocity while keeping the rotation speed of the vertical axis wind turbine constant, and during the control in the first regeneration mode When the wind speed becomes the second regeneration mode start reference value, the rotational speed of the alternator is controlled in accordance with the flow rate in the state where the second regeneration mode is entered and the generated current is kept constant at the maximum generated current. . By doing so, the energy of the fluid is exchanged for electric energy more effectively with less loss.

JP 2005-295626 A JP 2014-199055 A

However, the power generator of Patent Document 2 still has room for improvement, and a power generator capable of exchanging further wind energy with power generation energy is desired.
An object of the present invention is to solve the above-described problems and provide a power generator that can exchange wind energy more widely with electric energy.

  In order to solve the above problems, a power generator according to the present invention includes a vertical axis wind turbine that converts wind kinetic energy into mechanical kinetic energy, an AC generator driven by the vertical axis wind turbine, and the AC generator. An AC output from the inverter, a power storage unit that stores DC power from the inverter, a wind speed detection unit that detects wind speed, and the AC power generation according to the moving average wind speed calculated based on the wind speed In the power generation apparatus including a control unit that controls the machine in the regenerative mode via the inverter, the regenerative mode includes a high efficiency range in which a peripheral speed ratio of the vertical axis wind turbine includes a maximum output coefficient of the vertical axis wind turbine. And a low-efficiency regenerative mode performed in a low-efficiency range that does not include the maximum output coefficient, and the control unit, when the moving average wind speed is equal to or higher than a low-efficiency determination threshold The AC generator is controlled in the low efficiency regeneration mode via the inverter, and the AC generator is operated in the high efficiency regeneration mode via the inverter when the moving average wind speed is less than the low efficiency determination threshold value. It is something to control.

  The control unit is configured to control in the regeneration mode or the power running mode via the inverter, the high efficiency regeneration mode includes a first regeneration mode and a second regeneration mode, and the control unit includes a power running When the moving average wind speed increases during control in the mode and exceeds the first regeneration mode start reference value, the first regeneration mode is used to generate power in proportion to the wind speed with the rotation speed of the vertical axis wind turbine being constant. When the current is controlled and the moving average wind speed exceeds the second regeneration mode start reference value during the control in the first regeneration mode, the generation current is kept constant as the second regeneration mode. It is preferable to rotate the vertical axis wind turbine according to the moving average wind speed.

Moreover, it is preferable that the said control part starts control of the said AC generator in power running mode, when the said moving average wind speed is slower than power running mode start reference value.
In addition, the control unit performs control in the gust response mode when the wind speed satisfies the gust determination condition, and the control unit in the gust response mode is more than the generated current in the low efficiency regeneration mode. It is preferable to control the inverter so as to output a large generated current.

  According to the present invention, it is possible to exchange wind energy more widely with electric energy.

The block diagram of the whole structure of one Embodiment which actualized this invention to the wind power generator. The flowchart of the electric power generation program which a controller performs. Current / torque characteristics diagram of the AC generator. Rotation speed / generated voltage characteristics diagram of AC generator. Rotation speed / torque characteristics diagram of AC generator. The characteristic figure of the rotation speed and power generation output of an AC generator. Explanatory drawing of the electric power generation electric current, electric power generation output, and rotation speed for demonstrating the switching timing of 1st regeneration mode and 2nd regeneration mode. Explanatory drawing of the effect | action which shows the relationship between the wind speed of one Embodiment, and time. (A) is explanatory drawing which shows the relationship between the electric current in each mode, and time, (b) is explanatory drawing which shows the relationship between the rotational speed in each mode, and time, (c) is the circumferential speed ratio and time of each mode. Explanatory drawing of the effect | action which shows a relationship. Explanatory drawing which shows the relationship between the rotation speed (rotation speed) and torque of the alternating current generator of one Embodiment. The characteristic diagram of output coefficient Cp and peripheral speed ratio (lambda). Explanatory drawing of the relationship between the wind speed V at the time of Cp maximum peripheral speed ratio, and the rotation speed N of a rotor. Illustration of actual wind speed and average wind speed. The flowchart of the electric power generation program which the controller of other embodiment performs.

Hereinafter, an embodiment in which the power generation device of the present invention is embodied in a wind power generation device will be described with reference to FIGS.
As shown in FIG. 1, the wind turbine generator 10 includes a vertical axis wind turbine 20, an AC generator 30 having a rotor (rotor) connected to the vertical axis 24 of the vertical axis wind turbine 20, and a stator of the AC generator 30. The inverter 40 is connected, and a secondary battery 60 as a power storage unit connected to the inverter 40 via a smoothing capacitor 50 is provided. The vertical axis wind turbine 20 and the AC generator 30 may be directly connected, or may be connected via a speed reduction mechanism or a speed increasing mechanism.

  In the present embodiment, the vertical axis wind turbine 20 is a Darrieus type wind turbine, and includes a wind turbine blade 22, a vertical shaft 24, and the like. In FIG. 1, the vertical axis wind turbine 20 is illustrated in a simplified manner for convenience of explanation. The vertical axis windmill 20 is not limited to a Darrieus type windmill, but may be a Savonius type windmill, a gyromill type windmill, a cross flow type windmill, or the like.

  The vertical axis wind turbine 20 includes a mechanical brake 26 as a lock portion, and can be prevented from rotating by the mechanical brake 26 in a state where a power generation program described later is not activated. The mechanical brake 26 is controlled by the controller 80 and can unlock the rotation stop of the vertical axis wind turbine 20.

  The AC generator 30 may be either a synchronous generator (for example, a permanent magnet type synchronous generator) or an induction generator. In the present embodiment, the AC generator 30 has U, V, and W phase windings.

  The inverter 40 converts the AC power output from the AC generator 30 into DC power during regeneration, stores the DC power in the secondary battery 60, and stores the DC power of the secondary battery 60 in the power running mode. It converts into alternating current power, and the alternating current generator 30 operates as a motor.

  That is, the inverter 40 has a half-bridge circuit in which diodes D1 to D6 are connected in series, and switching elements 42 to 47 made of transistors, IGBTs, and MOSs are connected in parallel to each diode. . In the present embodiment, the switching elements 42 to 47 are composed of IGBTs.

  The inverter 40 can be driven to cause the AC generator 30 to generate electricity during regeneration. Further, the inverter 40 can be driven to operate the AC generator 30 in the power running mode as necessary. The diode bridge of the inverter 40 has a rectifying function, and converts the generated AC voltage into a DC voltage. Then, by appropriately controlling on / off of the switching elements 42 to 47 in the inverter 40, the AC generator 30 is caused to regenerate current appropriately, and the output of the stator winding of the AC generator 30 is utilized by using the inductance. Control of voltage, output current, etc. is possible.

  A converter 90 is connected to the secondary battery 60. The converter 90 converts DC power sent from the secondary battery 60 into AC power having a fixed frequency (for example, commercial frequency), and supplies the AC power having the fixed frequency to the power system via the grid interconnection transformer 100. Supply to the grid.

  Further, the wind power generator 10 includes a controller 80 that is controlled via a driver 70 of the switching elements 42 to 47 constituting the inverter 40. The controller 80 includes a CPU (Central Processing Unit) (not shown), a ROM that stores a system program, a RAM that is a working memory, and a rewritable storage device (not shown) that stores a power generation program. The controller 80 corresponds to a control unit.

  The controller 80 receives a detection signal of the speed sensor 32 for detecting the rotational speed (the number of revolutions per unit rotational time) and the position of the rotor (rotor) of the AC generator 30. The speed sensor 32 is configured by a resolver in the present embodiment, but is not limited to the resolver, and may be an encoder. A current sensor Su, Sv, Sw is connected to the controller 80, and a detection signal of a current of each phase between the AC generator 30 and the inverter 40 is input. Based on the detection signal of the current of each phase, the controller 80 acquires the value of the generated current in the case of regeneration, and acquires the value of the drive current in the case of power running.

  Furthermore, the wind power generator 10 includes a voltage detection unit 52 that detects the voltage of the smoothing capacitor 50, that is, the DC output voltage of the inverter 40. The voltage detection unit 52 inputs detected voltages (detection signals) to the driver 70 and the controller 80, respectively.

The controller 80 is connected to an anemometer 110 as a wind speed detection unit that detects the flow velocity of the wind blown to the vertical axis wind turbine 20, and inputs a detection signal to the controller 80.
The controller 80 stores the input (acquired) various detection signals in a buffer (not shown) for each common detection cycle.

(Regeneration)
Explain regeneration. At the time of regeneration (including first and second regeneration modes, third regeneration mode and regenerative braking processing, which will be described later), the controller 80 causes all of the switching elements 42, 44, 46 on the high side to pass through the driver 70. PWM control is performed so that the low-side switching elements 43, 45, and 47 are turned on and off at the same timing while being maintained in the off state. In PWM (Pulse Width Modulation) control, a short-circuit current flows through the windings U, V, W during the period in which the low-side switching elements 43, 45, 47 are in an on state, and energy is generated in the windings U, V, W. As a result, the AC generator 30 is decelerated and braking force is generated by regenerative braking.

  Thereafter, when the switching elements 43, 45, 47 on the low side are turned off, voltages are induced in the windings U, V, W. When this induced voltage exceeds the battery voltage of the secondary battery 60, a regenerative current flows toward the secondary battery 60 via the diodes associated with each switching element, and the energy stored in the windings U, V, W is increased. The secondary battery 60 is charged while being discharged.

  Further, the braking force due to regenerative braking increases as the value of the regenerative current increases. The value of the regenerative current is controlled by the on-duty of the low-side switching elements 43, 45, and 47 in the PWM control, and the regenerative current increases as the on-duty ratio increases. The controller 80 adjusts the on-duty ratios of the switching elements 43, 45, and 47 on the low side so that a regenerative current indicated by a regenerative current command value to be generated can be obtained during various regenerations described later.

(Power running)
Describe power running. In the power running mode, the controller 80 turns on the switching elements 42 to 47 through the driver 70 in a certain order. As a result, the direction of the current flowing through the windings U, V, and W is sequentially switched to rotate the rotor. In the power running mode, the controller 80 generates a motor drive command value and adjusts the on-duty of the switching elements 42 to 47 so that a torque target value indicated by the motor drive command value is obtained.

(Operation of the embodiment)
Next, the effect | action of the wind power generator 10 is demonstrated with reference to FIGS. FIG. 2 is a flowchart in which the controller 80 controls the AC generator 30 via the inverter 40 in accordance with a power generation program stored in a storage device (not shown).

(S10)
When the power generation program is activated, in S10, the controller 80 initializes various parameters such as resetting history flags F0, F1, F2, F3, and the like. Before the power generation program is started, the vertical axis wind turbine 20 is locked in advance by the mechanical brake 26 and cannot rotate.

(S20)
In S20, the controller 80 detects the wind speed V from the anemometer 110, the voltage from the voltage detector 52, the phase current from the current sensors Su, Sv, Sw, the rotational speed input from the speed sensor 32 (that is, every unit time). The number of rotations) is read from the buffer.

(S30)
In S30, the controller 80 determines whether or not the wind speed V exceeds the allowable maximum wind speed Vmax allowed for the vertical axis wind turbine 20. When the wind speed V is equal to or higher than the maximum allowable wind speed Vmax, the process proceeds to S40, and when the wind speed V is less than the maximum allowable wind speed Vmax, the process proceeds to S50. Note that the detection cycle of the wind speed V is synchronized with a control cycle described later. Further, the controller 80 calculates the moving average of the wind speed V input every control cycle, and stores (that is, updates) the calculated moving average wind speed Vgr as a current value in a storage device (not shown). For example, the moving average wind speed Vgr is a moving average for the past 30 seconds, but is not limited to 30 seconds. Note that the moving average wind speed Vgr of the present embodiment is calculated by a simple moving average.

(S40)
In S40, the controller 80 locks the mechanical brake 26, stops the vertical axis windmill 20 from rotating, and exits this flowchart. Thus, in S40, when the wind speed V is equal to or greater than the allowable maximum wind speed Vmax, if the vertical axis wind turbine 20 is rotated, the vertical axis wind turbine 20 may be damaged. The rotation of the axial wind turbine 20 is stopped.

(S50)
In S50, the controller 80 determines whether or not the wind is a gust. The condition for determining whether or not the wind is a gust is as follows.

<Judgment conditions>
The determination condition is that the current value of the wind speed V is equal to or higher than the current value of the moving average wind speed Vgr and the differential value dV / dt of the wind speed V is equal to or higher than the gust determination threshold value α.

If the current wind speed V satisfies the determination condition (determination is “YES”), the process proceeds to S60, and if the determination condition is not satisfied (determination is “NO”), the process proceeds to S70.
(S60)
In S60, the controller 80 performs the process of the gust correspondence mode.

  Specifically, the controller 80 generates a regenerative current command value based on the moving average wind speed Vgr, and further generates a regenerative current command value obtained by adding a correction value to the regenerative current command value. In other words, the inverter 40 is controlled by the controller 80 so as to perform the process in the gust corresponding mode when a generated current (regenerative current) larger than the regenerative current command value is obtained.

  When the regenerative current command value after adding the correction value to the regenerative current command value exceeds the upper limit value Ic (generated current), the controller 80 adjusts the regenerative current command value to the upper limit value Ic. In other words, the generated current I in the regenerative braking process here is adjusted to be in the range of Ib <I ≦ Ic (see FIG. 3).

  Ib is the maximum generated current when the third regeneration mode is performed, and Ic is the maximum generated current in the gust compatible mode. Hereinafter, Ib is referred to as a second maximum generated current, and Ic is referred to as a third maximum generated current.

FIG. 3 shows the relationship between the generated current I (A) of the AC generator 30 and the torque T (N · m). The generated current I and the torque T are
T = k1 · I
There is a proportional relationship indicated by. k1 is a proportionality constant. In FIG. 3, Imax is the maximum generated current of the AC generator 30.

  FIG. 3 is a current / torque characteristic diagram of the AC generator 30, where the horizontal axis indicates current (including the generated current and drive current), and the vertical axis indicates torque T. In the figure, the generated current I during regeneration is Ia (first maximum generated current), the torque T is Ta, and when Ib (second maximum generated current), the torque T is Tb, and Ic ( In the case of the third maximum generated current), the torque T is Tc. In the power running mode, when the drive current is Id, the torque (drive torque) is Td.

  In this way, the controller 80 calculates the regenerative current command value, and controls the inverter 40 via the driver 70 based on the regenerative current command value. The AC generator 30 is regeneratively braked by the control of the inverter 40, and the rotational speed of the rotor is reduced.

  As shown in FIG. 3, in S60, the generated current I in the regenerative braking process is adjusted to be in the range of Ib <I ≦ Ic as described above, and therefore the torque T output from the AC generator 30 is set. Is in the range of Tb <T ≦ Tc.

When the process of S60 ends, the process returns to S30.
By performing the gust response mode processing of S60 in this way, as shown in FIG. 10, the rotation speed of the rotor (rotor) is in the first regeneration mode, the second regeneration mode, and the third regeneration mode. Even in the same case, torque and regenerative current (generated current) are larger than those in these modes.

  FIG. 10 is an explanatory diagram showing the relationship between the rotational speed (rotational speed) of the AC generator 30 and the torque, with the horizontal axis representing the rotational speed N and the vertical axis representing the torque T. In the same figure, the area | region when the 1st regeneration mode, the 2nd regeneration mode, the 3rd regeneration mode, the gust corresponding mode, and the power running mode mentioned later are performed is shown.

Here, the first regeneration mode and the second regeneration mode correspond to the high efficiency regeneration mode, and the third regeneration mode corresponds to the low efficiency regeneration mode.
In the rotational speed N on the horizontal axis, Na is the maximum value in the first regeneration mode, Nb is the maximum value in the second regeneration mode, and Nc is the maximum value in the third regeneration mode and the gust compatible mode. The value is shown. In FIG. 10, the maximum value of the rotational speed N in the power running mode is Na in this embodiment, but is not limited to Na, and may be smaller or larger than Na.

(S70)
In S70, the controller 80 determines whether or not the moving average wind speed Vgr or the like satisfies the following powering mode condition or the first regeneration mode condition.

(1. Power running mode conditions)
The power running mode condition includes the first condition or the second condition. If either of the conditions is satisfied, the controller 80 determines that the power running mode condition is satisfied.

(First condition)
This is a case where the moving average wind speed Vgr ≦ the power running mode start reference value Va and the history flag F1 (first regeneration mode flag) in the previous control cycle is set to “1”. The control cycle for executing S20 to S95, S20 to S105, S20 to S115, or S20 to S125 is a specified control cycle, and is, for example, several milliseconds to several tens of milliseconds.

  Here, the history flag F1 of the first condition is for determining whether or not the control is performed in the first regeneration mode in the previous control cycle. That is, it is assumed that the previous time was the first regeneration mode but this time the mode is shifted to the power running mode.

  The power running mode start reference value Va is a wind speed that is faster by a predetermined value than a first regeneration mode start reference value Vb, which will be described later, and a result obtained by a test or the like in advance according to the vertical axis wind turbine 20 and the AC generator 30 is set. Has been.

(Second condition)
This is a case where the moving average wind speed Vgr ≦ the first regeneration mode start reference value Vb and the history flag F0 (power running flag) in the previous control cycle is set to “1”.

  The history flag F0 (power running flag), history flag F1 (first regeneration mode flag), and history flag F2 (second regeneration mode flag) are set to “0” by the initialization process of S10. Therefore, when the moving average wind speed Vgr ≦ Vb and the history flags F0, F1, and F2 are all “0”, it is assumed that the second condition is satisfied as an exception.

  The first regeneration mode start reference value Vb is set to an extent that is faster than the wind speed at which the vertical axis wind turbine 20 stops due to the drag torque of the vertical axis wind turbine 20. Here, in the present embodiment, the first regeneration mode start reference value Vb <the power running mode start reference value Va is set in order to make an early transition from a powering mode described later to the first regeneration mode.

  The history flag handled in the second condition is used to determine whether or not the control is performed in the powering mode or immediately after starting from the initial value in the previous control cycle. That is, it is assumed that the previous time was the power running mode or immediately after startup, but this time the mode is shifted to the power running mode.

If the first condition or the second condition is satisfied in S70, the process proceeds to S90.
(2. First-generation mode conditions)
The first regeneration mode conditions are as follows.

  First regeneration mode start reference value Vb <moving average wind speed Vgr ≦ second regeneration mode start reference value Vc, and history flag F0 (power running flag) in the previous control cycle is “1”, history flag F1 (first regeneration mode) Flag) is set to “1”, or the history flag F2 (second regeneration mode flag) is set to “1”.

  Here, the history flag for determining in the first regeneration mode condition is controlled in the power running mode, the first regeneration mode, or the second regeneration mode in the previous control cycle, but this time the moving average wind speed Vgr is the second. It is assumed that the regeneration mode start reference value Vc has been reached.

(Regarding the setting method of the second regeneration mode start reference value Vc)
Here, a method for setting the second regeneration mode start reference value Vc will be described.
FIG. 4 shows the relationship between the rotational speed N (rpm, that is, the rotational speed) of the rotor per unit time of the AC generator 30 and the generated voltage E (V).
E = k2 · N
There is a proportional relationship indicated by. k2 is a proportionality constant. In FIG. 4, Emax is the maximum generated voltage of the AC generator 30.

  5 and 10 show the relationship between the rotational speed N (rpm) of the AC generator 30 and the torque T (N · m). When the rotational speed N is in the first range H1, the torque T is constant. Yes, when the rotational speed N increases in the second range H2 that exceeds the first range H1, the torque T gradually decreases. When the rotational speed N reaches the maximum rotational speed Nmax that is the rotational limit of the AC generator 30, the torque T is 0. Become. In addition, FIG. 10 is for demonstrating the relationship between the rotation speed N (rpm) and torque T (N * m), the period (I)-period (VI) mentioned later, and various modes. is there.

  FIG. 6 is a characteristic diagram showing the relationship between the rotational speed N (rpm) of the AC generator 30 and the power generation output PG. The power generation output PG (KW) is proportional to the rotation speed N when the rotation speed N (rpm) is in the first range H1, and when it exceeds the first range H1, the power generation output PG becomes constant at Pmax.

PG = ηG · N · T / 974 (1)
Note that ηG is power generation efficiency.
Based on the characteristics of the AC generator 30 as described above, the basic expression for the maximum output of the AC generator 30 is obtained.

The wind energy PW, which is a fluid, can be expressed by the following equation.
PW = (1/2) · ρ · S · V3 (W: Watts) (2)
S is an area where the windmill receives a fluid (wind), and ρ is an air density (fluid density). When the fluid is air, it is 0.124 kgs 2 / m ^ 4 (^ represents a power).

The rotational drive energy Pf and power generation output PG due to fluid (wind) are Pf = ηf × PW = PG
ηf: If the transmission efficiency of the wind turbine is assumed, and the generation efficiency ηG and the transmission efficiency ηf can be neglected, from the equations (1) and (2),
(1/2) ・ ρ ・ S ・ V3 ≒ N ・ T
It becomes the relationship.

From the above, the timing for switching between the first regeneration mode and the second regeneration mode can be derived.
As shown in FIG. 7, in the first regeneration mode, the rotational speed N (rpm) is kept constant until the generated current I reaches Ia (first maximum generated current) in the first regeneration mode, as will be described later. Therefore, the inverter 40 is controlled so as to increase or decrease the generated current I in proportion to the wind speed. When the generated current I reaches Ia, the operation mode shifts to the second regeneration mode as will be described later. In the second regeneration mode, the generated current is made constant (fixed) at Ia, and the rotational speed N (rpm) is set to the moving average wind speed Vgr. The inverter 40 is controlled so as to increase or decrease in accordance with the above.

  As the second regeneration mode start reference value Vc for the generated current I to reach Ia, a result obtained in advance by a test or the like is set in accordance with the AC generator 30 and the vertical axis wind turbine 20 to be used. The allowable maximum wind speed Vmax for reaching the maximum rotational speed Nmax is set as a result obtained by a test or the like in advance according to the AC generator 30 and the vertical axis wind turbine 20 to be used. The maximum rotational speed Nmax is the rotational speed of the rotor of the AC generator 30, but the AC generator 30 and the vertical axis wind turbine 20 are connected via a direct connection, a speed reduction mechanism, or a speed increase mechanism. Nmax is uniquely determined as the upper limit rotational speed of the vertical axis wind turbine 20. This Nmax is also the rotation limit of the vertical axis wind turbine 20.

When the first regeneration mode condition is satisfied, the process proceeds to S100.
In S70, the controller 80 proceeds to S80 when the moving average wind speed Vgr or the like does not satisfy the following powering mode condition and the first regeneration mode condition.

(S80)
In S80, the controller 80 determines whether the moving average wind speed Vgr satisfies the second regeneration mode condition or the third regeneration mode condition.

(3. Second generation mode conditions)
The second regeneration mode conditions are as follows.
Second regeneration mode start reference value Vc <moving average wind speed Vgr ≦ third regeneration mode start reference value Vd, and history flag F1 (first regeneration mode flag), history flag F2 (second regeneration mode flag), history flag One of F3 (third regeneration mode flag) is set to “1”. If the said conditions are satisfy | filled, the controller 80 will transfer to 2nd regeneration mode of S110.

(4. Third-generation mode conditions)
The third regeneration mode conditions are as follows.
Third regeneration mode start reference value Vd ≦ moving average wind speed Vgr ≦ maximum allowable wind speed Vmax, and either one of the history flag F2 (second regeneration mode flag) and the history flag F3 (third regeneration mode flag) is “1”. Is set to "." The third regeneration mode start reference value Vd corresponds to a low efficiency determination threshold value.

When the moving average wind speed Vgr and the history flag satisfy the above conditions, the controller 80 shifts to the third regeneration mode of S120.
(S90)
In S90, the controller 80 controls the alternator 30 via the inverter 40 in the power running mode with the mechanical brake 26 unlocked.

  That is, the controller 80 has a constant rotation of the wind turbine blades 22 (blades) of the AC generator 30 in the power running mode, that is, the rotation speed v (rotational speed N) of the rotor of the AC generator 30 is constant, and the generated voltage E And the inverter 40 is controlled so that the generated current I is constant, and the process proceeds to S95. Note that the generated current in this case is precisely a drive current for driving the AC generator 30 as a motor. In this embodiment, as shown in FIG. 3, the current I (drive current) is set to Id = Ia as a maximum value, but the value of Id is not limited to Ia, and even if it is smaller than Ia, it is large. May be.

(S95)
In S95, the controller 80 sets the history flag F0 (power running flag) to “1”, the history flag F1 (first regeneration mode flag), the history flag F2 (second regeneration mode flag), and the history flag F3 (third flag). The regeneration mode flag) is reset to “0”, and the process returns to S20.

(S100)
In S100, the controller 80 controls the AC generator 30 via the inverter 40 in the first regeneration mode with the mechanical brake 26 unlocked.

  That is, the controller 80 has a constant rotation of the wind turbine blades 22 (blades) of the AC generator 30 (that is, the rotational speed v (rotation speed N) of the rotor of the AC generator 30 is constant) and the generated voltage E is constant. And the inverter 40 is controlled so that the generated current I is proportional to the wind speed within a predetermined range of the peripheral speed ratio described later. The predetermined range of the peripheral speed ratio is between the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU. Thereafter, the controller 80 proceeds to S105. The upper limit peripheral speed ratio λU and the lower limit peripheral speed ratio λL will be described later.

(Relationship between peripheral speed ratio λ of windmill and output coefficient Cp)
Here, the relationship between the peripheral speed ratio λ and the wind turbine output coefficient Cp will be described.
The peripheral speed ratio λ is as follows.

Peripheral speed ratio λ = peripheral speed of windmill / wind speed Note that the peripheral speed of the vertical axis windmill 20 is the windmill windmill blade (blade) radius × rotational speed (rotational angular speed).

The output coefficient Cp is windmill output / wind power.
FIG. 11 is an explanatory diagram showing the relationship between the output coefficient Cp of the windmill and the peripheral speed ratio λ. When the shape of the windmill is determined, the output coefficient Cp with respect to the circumferential speed ratio λ is uniquely determined as shown in FIG. Further, as shown in FIG. 11, the peripheral speed ratio λ has a place where the wind turbine maximum output (that is, the maximum output coefficient Cpmax) is reached in a limited range, and the wind turbine maximum output as shown in FIG. The rotor rotational speed N and the wind speed (flow velocity) are in a proportional relationship.

  Therefore, as shown in FIG. 11, a range H including the maximum output coefficient Cpmax is set with a lower limit peripheral speed ratio λL and an upper limit peripheral speed ratio λU. The lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU may be set as appropriate so as to have values that sandwich the peripheral speed ratio λ that is the maximum output coefficient Cpmax. If the rotational speed of the wind turbine rotor is controlled to be within the range H set by the lower limit circumferential speed ratio λL and the upper limit circumferential speed ratio λU, the output coefficient Cp is set to the windmill maximum output (that is, the maximum output coefficient Cpmax). Can be held in the vicinity. That is, the rotational speed of the rotor of the wind turbine (in other words, the rotational speed of the rotor of the AC generator 30) that is at the moving average wind speed Vgr within the range H defined by the upper limit peripheral speed ratio λU and the lower limit peripheral speed ratio λL. If it can be controlled, the maximum output of the wind turbine can be obtained satisfactorily. In addition, the numerical value of the peripheral speed ratio λ on the horizontal axis and the numerical value of the output coefficient Cp on the vertical axis in FIG. 11 are examples, and differ depending on the type and shape of the windmill.

  In FIG. 11, the output coefficient Cpa at the upper limit peripheral speed ratio λU and the output coefficient Cpb at the lower limit peripheral speed ratio λL have different values, but these values differ depending on the windmill, Equivalent.

  FIG. 12 is an explanatory diagram showing the relationship between the wind speed V and the rotational speed N of the wind turbine rotor when the output coefficient Cp is the maximum peripheral speed ratio. In the figure, the horizontal axis is the wind speed V (m / s), and the vertical axis is the rotational speed N of the wind turbine rotor. In the figure, the solid line shows the characteristics of the wind speed V and the rotational speed N of the wind turbine rotor at the peripheral speed ratio λ in the case of the maximum output coefficient Cpmax. The alternate long and short dash line indicates the characteristics of the wind speed V and the rotational speed N of the wind turbine rotor at the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU, respectively.

  As described above, in the first regeneration mode, the controller 80 keeps the rotor rotational speed N constant with respect to the moving average wind speed Vgr within the range of the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU shown in FIG. The regenerative current command value is increased or decreased according to fluctuations in wind speed (moving average wind speed Vgr) with the rotational speed as a target.

(S105)
In S105, the controller 80 resets the history flag F0 (power running flag), the history flag F2 (second regeneration mode flag), and the history flag F3 (third regeneration mode flag) to “0”, and the history flag F1 (first regeneration flag). The regeneration mode flag) is set to “1”, and the process returns to S20.

(S110)
In S110, the controller 80 controls the AC generator 30 via the inverter 40 in the second regeneration mode in a state where the lock of the mechanical brake 26 is released.

  That is, the controller 80 controls the inverter 40 so as to keep the generated current I constant and the generated voltage E according to the wind speed, and proceeds to S115. Also in the second regeneration mode, the generated current I is made constant so that the peripheral speed ratio λ of FIG. 11 is performed between the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU. Specifically, in the second regeneration mode, the controller 80 targets a constant generated current value with respect to the moving average wind speed Vgr within the range of the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU shown in FIG. Thus, the regenerative control is performed, and the rotational speed N of the rotor is increased or decreased according to the fluctuation of the moving average wind speed Vgr.

  In S110, the controller 80 monitors the rotational speed N based on the detection signal of the speed sensor 32. If the rotational speed N reaches Nc (see FIG. 10), the mechanical brake 26 The rotation of the vertical axis wind turbine 20 is stopped and the regeneration control by the inverter 40 is stopped.

(S115)
In S115, the controller 80 resets the history flag F0 (power running flag), the history flag F1 (first regeneration mode flag), and the history flag F3 (third regeneration mode flag) to “0”, and the history flag F2 (second regeneration flag). The regeneration mode flag) is set to “1”, and the process returns to S20.

(S120)
In S120, the controller 80 sets the peripheral speed ratio λ to
Lower limit peripheral speed ratio λLL ≦ λ <lower limit peripheral speed ratio λL
In this range, a regenerative current command value is generated and the number of revolutions N of the rotor is increased or decreased according to the fluctuation of the moving average wind speed Vgr. The lowest-limit peripheral speed ratio λLL is the lowest-limit value of the peripheral speed ratio at which the vertical axis wind turbine 20 is allowed. The output coefficient Cp in this case is Cpc ≦ Cp <Cpb as shown in FIG. Cpc is an output coefficient when the lowest peripheral speed ratio λLL.

  In the first regeneration mode and the second regeneration mode, the peripheral speed ratio λ is controlled within the range between the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU so that the output coefficient Cp is maintained in the vicinity of the maximum output coefficient Cpmax. On the other hand, in the third regeneration mode, the peripheral speed ratio λ is different from the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU.

(S125)
In S125, the controller 80 resets the history flag F0 (power running flag), the history flag F1 (first regeneration mode flag), and the history flag F2 (second regeneration mode flag) to “0”, and the history flag F3 (third regeneration flag). The regeneration mode flag) is set to “1”, and the process returns to S20.

Next, the case where the moving average wind speed Vgr changes in each of the periods (I) to (V) as shown in FIG. 8 will be described as an example.
(1. About period (I))
The period (I) in FIG. 8 is an example of the moving average wind speed Vgr when the first regeneration mode condition is satisfied in S70 of the flowchart after the power generation program is started. During the period (I), the first regeneration mode start reference value Vb <the moving average wind speed Vgr ≦ the second regeneration mode start reference value Vc and the history flag F1 is set to “1”, so the period (I) The inside of the AC generator 30 is controlled through the inverter 40 in the first regeneration mode.

  Therefore, as shown in FIG. 9B, during the period (I), the rotational speed v (rotational speed N) of the rotor of the AC generator 30 is constant, so that the wind turbine blades 22 (blade) of the vertical axis wind turbine 20 are maintained. ) Rotation speed is constant. In addition, in the period (I) of FIG. 9B and the period (III) described later, “constant number of rotations” is described. “Constant rotation speed” means that the control is performed at a constant rotation speed for a short time (control cycle level). The rotational speed shown in the period (I) of FIG. 9 (b) is not the level of the control cycle, and if the wind speed changes at a level longer than that, as shown in FIG. 9 (a), The generated current I is proportional to the wind speed. Therefore, since the alternator 30 is controlled in proportion to the wind speed (this wind speed is an average wind speed), it is illustrated that the rotational speed of the rotor is changing. In addition, as shown in FIG. 13, the actual wind speed at the place where the windmill is installed generally fluctuates greatly in several seconds. It should be understood that in the period (I) and the period (III) of the present embodiment, control is performed in the regeneration mode according to the moving average wind speed, not the actual wind speed.

  Further, in FIG. 9C, the peripheral speed ratio λ is shown to be constant and not changed in the period (I) and the period (III) described later. For the sake of convenience, it is shown that the peripheral speed ratio λ is maintained between the peripheral speed ratio λU and the lower limit peripheral speed ratio λL. Actually, in the period (I) and the period (III) described later, the circumferential speed ratio λ is within the range of the upper limit circumferential speed ratio λU and the lower limit circumferential speed ratio λL according to the moving average wind speed Vgr. Will fluctuate.

(2. About period (II))
Period (II) in FIG. 8 is an example of the moving average wind speed Vgr when the power running mode condition is satisfied in S70 of the flowchart after the power generation program is started.

  When the moving average wind speed Vgr is the moving average wind speed Vgr ≦ the power running mode start reference value Va and the history flag F1 (first regeneration mode flag) in the previous control cycle is set to “1”, the power running mode In order to satisfy the first condition among the conditions, the mode is shifted to the power running mode. After entering this period (II), the history flag F0 (power running flag) is set to “1”, and during the subsequent period (II), the moving average wind speed Vgr <the first regeneration mode start reference Since the value is Vb, the second condition is satisfied.

Therefore, during the period (II), the AC generator 30 is controlled via the inverter 40 in the power running mode.
Therefore, as shown in FIG. 9B, during the period (II), the rotor of the AC generator 30 is in power running and the rotational speed v (rotational speed N) is constant except for the transition period from the period (I). Thus, the rotational speed of the wind turbine blades 22 (blades) of the vertical axis wind turbine 20 is constant.

(3. About period (III))
The period (III) in FIG. 8 is an example of the wind speed when the first regeneration mode condition is satisfied in S70 of the flowchart after the period (II) has elapsed.

  When the moving average wind speed Vgr satisfies the first regeneration mode start reference value Vb <moving average wind speed Vgr ≦ second regeneration mode start reference value Vc, the history flag F0 in the previous control cycle is set to “1”. Therefore, in order to satisfy the first regeneration mode condition, the mode is shifted to the first regeneration mode.

  During the period (III), the first regeneration mode start reference value Vb <moving average wind speed Vgr ≦ the second regeneration mode start reference value Vc and the history flag F1 is set to “1”, so the period (III) The inside of the AC generator 30 is controlled through the inverter 40 in the first regeneration mode.

  Accordingly, as shown in FIG. 9B, during the period (III), the rotational speed v (rotational speed N) of the rotor of the AC generator 30 is constant. ) Rotation speed is constant. Moreover, as shown in FIG. 9A, the generated current I is proportional to the wind speed.

(4. About period (IV))
The period (IV) in FIG. 8 is an example when the second regeneration mode condition is satisfied in S80 of the flowchart after the period (III) has elapsed.

  When the moving average wind speed Vgr satisfies the second regeneration mode start reference value Vc <moving average wind speed Vgr <allowable maximum wind speed Vmax, the second regeneration mode condition is satisfied, so that the second regeneration mode is entered. During this period (IV), since the second regeneration mode start reference value Vc <moving average wind speed Vgr <allowable maximum wind speed Vmax, the AC generator 30 is controlled via the inverter 40 in the second regeneration mode.

  That is, in the second regeneration mode, the generated current I is constant (fixed) at Ia when the peripheral speed ratio λ is within the range of the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU, and the rotor of the AC generator 30 rotates. The inverter 40 is controlled so as to increase or decrease the number N (rpm) according to the moving average wind speed Vgr. Therefore, as shown in FIGS. 8 and 9B, during the period (IV), the rotational speed of the rotor of the AC generator 30 is in accordance with the moving average wind speed Vgr, so that the windmill blade 22 (blade) The number of rotations (rotational speed) also depends on the wind speed.

  In the present embodiment, as shown in FIG. 9A, in the second regeneration mode of the period (IV), the generated current I is made constant at Ia, and the rotational speed of the vertical axis wind turbine 20 is controlled in proportion to the wind speed. It becomes possible to expand the power generation area to the limit range of the mechanism of the vertical axis wind turbine, and the total power generation amount can be increased.

(5. About period (V))
The period (V) in FIG. 8 is an example in which the third regeneration mode condition is satisfied in S80 of the flowchart after the period (IV) has elapsed.

  The moving average wind speed Vgr is the third regeneration mode start reference value Vd ≦ moving average wind speed Vgr ≦ allowable maximum wind speed Vmax, and history flag F2 (second regeneration mode flag) and history flag F3 (third regeneration mode flag). Since either one of these is set to “1”, the third regeneration mode condition is satisfied. For this reason, it shifts to the 3rd regeneration mode.

  In the third regeneration mode during this period (V), the peripheral speed ratio λ is within the range of the minimum lower limit peripheral speed ratio λLL ≦ λ <the lower limit peripheral speed ratio λL, and the regenerative current according to the fluctuation of the moving average wind speed Vgr. A command value is generated, and the rotational speed N of the rotor increases or decreases.

  Thus, in the first regeneration mode and the second regeneration mode, the peripheral speed ratio λ is within the range between the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU so that the output coefficient Cp is maintained in the vicinity of the maximum output coefficient Cpmax. On the other hand, in the third regeneration mode, the peripheral speed ratio λ is within the range of the lower limit peripheral speed ratio λL and the upper limit peripheral speed ratio λU.

In the current / torque characteristic diagram of the AC generator in FIG. 3, it is shown in which region the periods (I), (II), (III), (IV), (V), and (VI) are performed. Show.
Further, in the explanatory diagram showing the relationship between the rotation speed (rotation speed) and the torque in FIG. 10, the above periods (I), (II), (III), (IV), (V), and (VI) are It shows in which area it is performed.

  When power generation control is performed on a wind whose wind speed fluctuates drastically, a moving average of the wind speed is taken as a reference for power generation control, and power generation is feedback controlled based on the moving average wind speed. Conventionally, when the wind speed becomes high and the wind energy becomes too large, the rotation of the blades of the windmill (the moving blade) is stopped. On the other hand, in the present embodiment, in the third regeneration mode which is the low efficiency regeneration mode, a range of low efficiency between the lower limit peripheral speed ratio λLL and the lower limit peripheral speed ratio λL that does not include the maximum output coefficient Cpmax. It also generates electricity. For this reason, unlike conventional ones, electric energy can be exchanged more widely for wind energy.

  Conventionally, the wind speed has fluctuated greatly in a few seconds. Especially for large instantaneous wind speed changes such as gusts of wind, as a safety measure for runaway, the wind turbine speed should be kept low and the wind turbine output reduced. I was doing.

  In the power generation device of the present embodiment, when there is a gust of wind, regeneration is performed without stopping the rotation of the moving blades in the gust response mode. For this reason, unlike conventional ones, electric energy can be exchanged more widely for wind energy.

This embodiment has the following features.
(1) In the power generation device of the present embodiment, the regeneration mode includes the first regeneration mode and the second regeneration that are performed in a high efficiency range in which the peripheral speed ratio λ of the vertical axis wind turbine 20 includes the maximum output coefficient Cpmax of the vertical axis wind turbine 20. A mode (high efficiency regeneration mode) and a third regeneration mode (low efficiency regeneration mode) performed in a low efficiency range not including the maximum output coefficient Cpmax are included. When the moving average wind speed Vgr is equal to or higher than the third regeneration mode start reference value Vd (low efficiency determination threshold), the controller 80 (control unit) controls the AC generator 30 in the low efficiency regeneration mode via the inverter 40 to move When the average wind speed Vgr is less than the third regeneration mode start reference value Vd (low efficiency determination threshold), the AC generator 30 is controlled in the high efficiency regeneration mode via the inverter 40. As a result, according to the present embodiment, in the third regeneration mode that is the low-efficiency regeneration mode, the low-efficiency range between the lower-limit peripheral speed ratio λLL and the lower-limit peripheral speed ratio λL that does not include the maximum output coefficient Cpmax. It also generates electricity. For this reason, unlike the past, wind energy can be exchanged for electric energy more widely.

  (2) In the power generation device of the present embodiment, the controller 80 (control unit) is controlled in the first to third regeneration modes or the power running mode via the inverter 40. Further, the high efficiency regeneration mode includes a first regeneration mode and a second regeneration mode. When the moving average wind speed Vgr becomes faster and exceeds the first regeneration mode start reference value Vb during control in the power running mode, the controller 80 (control unit) keeps the rotational speed of the vertical axis wind turbine 20 constant as the first regeneration mode. In this state, the generated current is controlled in proportion to the wind speed. Further, when the moving average wind speed Vgr exceeds the second regeneration mode start reference value Vc during the control in the first regeneration mode, the second regeneration mode is set according to the moving average wind speed in a state where the generated current is constant. The vertical axis wind turbine 20 is rotated.

  As a result, according to the present embodiment, in the first regeneration mode, since the output coefficient Cp is performed in a range including the maximum value, power generation can be performed efficiently. Further, in the second regeneration mode, since the generated current I is constant and the rotational speed of the vertical axis wind turbine 20 is controlled in proportion to the wind speed, it is possible to expand the power generation area toward the limit range of the mechanism of the vertical axis wind turbine. The total power generation can be increased.

  (3) In the power generator of the present embodiment, the controller 80 (control unit) starts control of the AC generator 30 in the power running mode when the moving average wind speed Vgr is slower than the power running mode start reference value. As a result, in the present embodiment, for example, when the moving average wind speed Vgr is small at the start-up when the wind turbine rotor is not rotating, the moving average wind speed Vgr is actively rotated in the power running mode, and the moving average wind speed Vgr is the power running mode start reference value. If it exceeds, it is possible to smoothly shift to the regeneration mode.

  (4) In the power generator of this embodiment, the controller 80 (control unit) controls the gust response mode when the wind speed satisfies the gust detection condition. That is, the controller 80 controls the inverter 40 so as to output a generated current larger than the generated current in the low-efficiency regeneration mode in the gust response mode. As a result, a braking force greater than that in the regenerative mode can be obtained, and the rotation of the windmill blade 22 can be suppressed.

In addition, this invention is not limited to the said embodiment, You may comprise as follows.
In the embodiment, the power running mode may be omitted.

  In the above embodiment, the moving average wind speed Vgr is calculated by the simple moving average, but is not limited to the simple moving average, and may be another moving average, for example, a weighted moving average, an exponential moving average, or the like. . For example, in the case of a weighted moving average and an exponential moving average, in order to attach importance to recent data, the weight is weighted more recently, and the weight is lighter the older data.

  In the above embodiment, S95, S105, S115, and S125 may be omitted as shown in FIG. That is, the history flag may be omitted. Even if it is the structure of such a power generator, the effect similar to (1) of the said embodiment is acquired.

10 ... wind power generator, 20 ... vertical axis windmill, 22 ... windmill blade,
24 ... Vertical axis, 26 ... Mechanical brake, 30 ... Alternator,
32 ... speed sensor, 40 ... inverter, 50 ... smoothing capacitor,
52 ... Voltage detection unit, 60 ... Secondary battery (power storage unit), 70 ... Driver,
80 ... Controller (control unit), 90 ... Converter,
DESCRIPTION OF SYMBOLS 100 ... Transformer for grid connection, 110 ... Anemometer (wind speed detection part).

Claims (4)

A vertical axis wind turbine for converting wind kinetic energy into mechanical kinetic energy, an AC generator driven by the vertical axis wind turbine, an inverter for converting AC output of the AC generator to DC, and a DC from the inverter A power storage unit that stores electric power; a wind speed detection unit that detects wind speed; and a control unit that controls the AC generator in a regenerative mode via the inverter according to a moving average wind speed calculated based on the wind speed. In the power generator provided,
The regeneration mode includes a high efficiency regeneration mode in which a peripheral speed ratio of the vertical axis wind turbine is in a high efficiency range including the maximum output coefficient of the vertical axis wind turbine and a low efficiency in a low efficiency range not including the maximum output coefficient. Including regeneration mode,
When the moving average wind speed is equal to or higher than the low efficiency determination threshold, the control unit controls the AC generator in the low efficiency regeneration mode via the inverter, and the moving average wind speed is less than the low efficiency determination threshold. In this case, the power generator controls the AC generator in a high-efficiency regenerative mode via the inverter. The control unit controls the regeneration mode or power running mode via the inverter,
The high-efficiency regeneration mode includes a first regeneration mode and a second regeneration mode,
When the moving average wind speed becomes faster during control in the power running mode and exceeds the first regeneration mode start reference value, the control unit is in a state in which the rotation speed of the vertical axis wind turbine is constant as the first regeneration mode Then, the generated current is controlled in proportion to the wind speed,
During the control in the first regeneration mode, when the moving average wind speed exceeds the second regeneration mode start reference value, the second regeneration mode is set according to the moving average wind speed in a state where the generated current is constant. The power generation device according to claim 1, wherein the vertical axis wind turbine is rotated.   The power generator according to claim 1 or 2, wherein the control unit starts control of the AC generator in a power running mode when the moving average wind speed is slower than a power running mode start reference value. When the wind speed satisfies the gust detection condition, the control unit performs control of the gust response mode.
4. The control unit according to claim 1, wherein the control unit controls the inverter so as to output a generated current larger than a generated current in the low-efficiency regeneration mode in the gust response mode. 5. Power generator.

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