KR101358276B1 - Wind power generating system and operating method under emergency condition - Google Patents

Abstract

A wind power generation system and an operating method for the same under emergency conditions are disclosed. The wind power generation system which controls the angle of a blade and a yaw angle under the emergency conditions comprises a power converter, a blade angle control unit, a yaw angle control unit, a yaw driving unit, and a system control unit. The power converter is connected between a power generator and a system to provide power generated from the power generator to the system. The blade angle control unit is supplied with operating power from a battery under the emergency conditions, and controls the blade angle by operating a motor for adjusting the angle of the blade according to control signals. The yaw angle control unit controls the yaw angle by operating a yaw motor according to the control signals. The yaw driving unit is connected to the power converter and system through first and second switches to supply the operating power to the yaw angle control unit. The system control unit supplies the operating power to the yaw angle control unit by controlling the opening and closing of the first and second switches based on the operating condition of the wind power generation system. [Reference numerals] (140) System control unit

Description

Wind power generation system and its method of operation in emergency operation state {Wind power generating system and operating method under emergency condition}

The present invention relates to a wind power generation system and an operating method thereof in an emergency operation state.

The utilization of renewable energy in the current grid power supply is growing beyond the level of the existing power generation system (fired, hydro, nuclear).

In addition, the large-scale grid-tied wind power generation system is closely related to the existing power generation system. Therefore, when the system accident occurs, the ripple effect has a great influence on the stability of the existing system.

In order to prevent such ripple effects, standards for various types of renewable energy sources are being made. Among them, the wind power generation system is called LVRT (Low Voltage Ride Through), which prevents separation from the system for a certain time when returning after a short power outage. The specification is made to operate according to the system internal standard.

In LVRT situations or when the grid voltage is lost, the blade vane angle of the wind power generation system is folded to a predefined set angle (eg 92 degrees) to stop the system's mechanical energy input. If the system voltage restoration situation occurs during the stop operation, the system is designed to resume normal operation. Korean Laid-Open Patent Publication No. 10-2011-0030655 also discloses a technique for controlling the number of revolutions of the generator by controlling the pitch angle of the windmill blades in the event of an accident in the power system.

In addition, the power converter is designed to consume the input electrical energy as thermal energy in the event of a wind power system accident by attaching a load resistor.

However, if a large amount of energy is supplied to the power converter due to the system control delay after the system is shut down in the rated operation situation, there is still a risk that the power converter will be damaged unless it consumes electrical energy.

Korean Patent Publication No. 10-2011-0030655

The present invention performs an yaw angle control in addition to the blade wing angle control in an emergency operation state such as an LVRT situation or a grid voltage loss situation in an emergency operation state in which the input energy to the wind power generation system can be reduced more quickly. It is to provide a wind power generation system and a driving method thereof.

The present invention is to provide a wind power generation system and its operating method in an emergency operation state that can increase the stability of the power converter and the wind power generation system and maximize the amount of power generation to enable stable system operation.

Other objects of the present invention will become readily apparent from the following description.

According to an aspect of the present invention, a wind power generation system that controls the blade angle and yaw angle of the blade in the emergency operation state, the power is connected between the generator and the grid to pass the power produced by the generator to the grid A conversion device; According to the control signal to drive the blade blade angle control motor to perform the wing angle control, in the emergency operation state wing angle control unit receives the operating power from the battery; A yaw angle control unit configured to drive a yaw motor according to a control signal to perform yaw angle control; A yaw driver connected to the system via a first switch, and connected to the power converter through a second switch, and supplying operation power to the yaw angle controller; And a system controller configured to control an opening and closing operation of the first switch and the second switch according to an operating state of the wind power generation system so that operating power is supplied to the yaw angle control unit.

The system controller may turn off the first switch and turn on the second switch in an emergency operation state so that the power stored in the power converter is the input power of the yaw angle controller.

The system control unit may generate the control signal for changing the wing angle and yaw angle so that the wind hit angle area of the blade is minimum in the emergency operation state, and output the control signal to the wing angle control unit and the yaw angle control unit, respectively.

The emergency operation state may be an LVRT situation or a system accident situation.

On the other hand, according to another aspect of the present invention, there is provided an operating method of a wind power generation system in which the system control unit controls the blade angle and yaw angle of the blade in the emergency operation state and a recording medium in which a program for performing the same is recorded.

According to one embodiment, a method of operating a wind power generation system in an emergency operation state includes: (a) controlling the vane angle to a stop angle when system power is lost; (b) changing the input power of the yaw driver to the power of the power converter from the system power; And (c) controlling the yaw angle in the stop direction.

(d) determining whether the system power is restored within a predetermined time; (e) The method may further include recognizing and processing as an LVRT situation when recovering, and recognizing and processing as a system accident situation when not recovering.

In the case of recognizing an LVRT situation, the step (e) may include: (e1) changing the input power of the yaw driver from the power of the power converter to the system power; (e2) controlling the yaw angle in the direction of power generation.

If it is recognized as a system accident, step (e) includes: (e1) stopping operation of the generator until the system power is restored; (e2) after the system power is restored, switching the system to an initial operation mode and changing the input power of the yaw driver from the power of the power converter to the system power.

Other aspects, features, and advantages will become apparent from the following drawings, claims, and detailed description of the invention.

According to an embodiment of the present invention, in addition to blade blade angle control in an emergency operation state such as LVRT situation or grid voltage loss situation, yaw angle control can be performed together to reduce the input energy to the wind power generation system in a shorter time. It works.

In addition, it is possible to increase the stability of the power converter and wind power generation system and to maximize the amount of power generation.

1 is a view showing the operation of the wind power generation system in the emergency operation state according to an embodiment of the present invention,
2 is a view schematically showing the structure of a wind power generation system according to an embodiment of the present invention;
3 is a flow chart of a driving method of a wind power generation system in an emergency driving state according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

In addition, the terms “… unit”, “… unit”, “… module” described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. Can be.

It is to be understood that the components of the embodiments described with reference to the drawings are not limited to the embodiments and may be embodied in other embodiments without departing from the spirit of the invention. It is to be understood that although the description is omitted, multiple embodiments may be implemented again in one integrated embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

1 is a view showing the operation of the wind power generation system in the emergency operation state according to an embodiment of the present invention.

Referring to FIG. 1A, in a normal operation state, the wind power generation system 100 rotates the tower top (nacelle 20) so that the hub 11 faces the main wind direction in which the wind blows, and the blade ( 10) It also has a wing angle (eg 0 degrees) to maximize the wind angle to allow for maximum wind acceptance.

However, the wind power generation system 100 according to an embodiment of the present invention first controls the blade angle of the blade 10 when it is in an emergency operation state such as, for example, an LVRT situation or a system accident situation, so that the wind hit angle area is minimized. To the wing angle (for example, 90 degrees), and the yaw angle is controlled so as to have a predetermined set angle (for example, 90 degrees) with respect to the main wind direction (the nacelle 20). By rotating (yawing motion), the input energy value can be reduced in a shorter time. Here, blade blade angle control and yaw angle control may be performed in any order or simultaneously.

Hereinafter, a structure and a driving method of a wind power generation system according to an embodiment of the present invention will be described with reference to the accompanying drawings.

2 is a view schematically showing the structure of a wind power generation system according to an embodiment of the present invention.

As described in FIG. 1, the wind power generation system according to the present embodiment simultaneously performs yaw angle control (yawing motion) as well as blade angle control of the blade in an emergency operation state (eg, LVRT situation or system accident situation). By doing so, it is possible to reduce the input energy value to the wind power generation system in a shorter time.

2, the wind power generation system 100 according to an embodiment of the present invention includes a generator 110, a power converter 130, a system controller 140, a wing angle controller 150, and a yaw angle controller ( 160, the yaw driver 165.

The generator 110 generates three phase AC power of variable frequency from the rotation of the turbine. The three phase AC power generated by the generator 110 may have a voltage magnitude of 3.3 kV, for example. For example, the generator 110 may be a renewable energy generator that rotates a turbine using a renewable energy source such as wind power.

The grid 120 is also called a grid, and is an AC power system provided by a power company or a power generation company. For example, grid 120 is an electrical link that spans a large area, including power plants, substations, and transmission lines.

The power converter 130 performs a function of stably transferring the power generated by the generator 110 to the system 120. The power converter 130 may be one of a structure that converts AC power into DC power or converts DC power into AC power, or converts AC power into DC power and then converts it into AC power.

The power converter 130 may include a generator-side converter 132, a DC link 134, and a grid-side converter 136. The generator-side converter 132 is connected to the generator 110 side to control the output of the generator, the grid-side converter 136 is connected to the grid 120 side is synchronized to the phase of the grid power source to produce in the generator 110 It serves to pass the power to the system 120. The DC link 134 between the generator-side converter 132 and the grid-side converter 136 compensates for instantaneous power imbalance, and a capacitor having a very large capacity is generally used.

The wing angle controller 150 rotates the blade angle of the blade installed at the hub of the nacelle tip by a predetermined angle under the control of the system controller 140. The wing angle controller 150 may include a blade wing angle adjustment motor, and the blade angle control may be performed to maximize or minimize the wind angle by adjusting the blade angle of the blade by driving the blade wing angle adjustment motor. .

The yaw angle controller 160 rotates the tower top (nacelle) by a predetermined angle under the control of the system controller 140. The yaw angle controller 160 may include a yaw motor, and may further include a yaw encoder (not shown) indicating a current position (current yaw angle) of the yaw motor as necessary. Yaw angle control may be performed by the yaw angle control unit 165 to drive the yaw motor to position the tower top in parallel with the main wind direction or perpendicular to the main wind direction.

Here, the wing angle control unit 150 and yaw angle control unit 160 operates by receiving system power in a normal operation state. In the emergency operation state, the wing angle control unit 150 is provided with a separate power storage device (for example, a battery), and there is no problem in its operation even when the system power is not supplied.

However, since the yaw angle control unit 160 does not have a separate power storage device, a configuration for driving the yaw angle control unit 160 in an emergency operation state in which the system power is not supplied is required.

In the present embodiment, smooth power supply to the yaw angle control unit 160 in the normal operation state and emergency operation state by using the yaw driver 165 selectively connected to the grid 120 and the power converter 130 according to the switch operation. Let this be done.

To this end, the yaw driver 165 includes a first AC / DC converter 166, a DC terminal capacitor 167, and a second DC / AC converter 168.

The first AC / DC converter 166 is connected to the system 120, and the first switch 170 is disposed therebetween, so that the first AC / DC converter 166 is connected to the system 120 according to the ON / OFF of the first switch 170. AC power input from 120 is allowed or blocked.

The DC link capacitor 167 is disposed between the first AC / DC converter 166 and the second DC / AC converter 168, is connected to the DC link 134 of the power converter 130, and the DC link A second switch 175 is disposed between 134 and the DC power input from the power converter 130 is allowed or blocked according to the on / off of the second switch 175.

The first switch 170 and the second switch 175 are complementary to operate so that when one is turned on, the other is turned off so that only one power source is drawn into the yaw driver 160. The first switch 170 and the second switch 175 may be, for example, a magnetic contactor (MC) in which a contact is opened and closed by an electromagnetic coil.

When the first switch 170 is turned on and the second switch 175 is turned off, the yaw driver 160 is connected to the system 120 to input system power, and the first switch 170 is turned off and the second switch ( When the power supply unit 175 is turned on, the yaw driver 160 is connected to the power converter 130 to receive the generation power of the generator 110 stored in the DC link 134.

The second DC / AC converter 168 has a rear end connected to the yaw angle control unit 160, and operates the yaw angle control unit 160 using a system power source or a DC link power source.

Hereinafter, a method of operating the wind power generation system will be described in detail.

3 is a flowchart illustrating a method of operating a wind power generation system in an emergency driving state according to an embodiment of the present invention.

Operation method of the wind power generation system in the emergency operation state according to an embodiment of the present invention is divided into LVRT situation (first emergency operation state) and system accident situation (second emergency operation state) according to the type of emergency operation state The driving method is different.

First assume that the system power is lost. The LVRT situation refers to a case in which the system power is temporarily lost and is restored soon. The grid loss situation refers to a case in which the system power is not restored for a predetermined time or more.

In step S210, the system control unit 140 detects a loss of system power and performs wing angle control at a stop angle. The wing angle control folds the blade's wing angle to a predefined set angle ('stop angle', for example, 92 degrees) so that the wind angle is minimized so that the mechanical energy input of the system can be reduced. It is. The system controller 140 transmits a command to rotate the blade angle of the blade by the difference angle to the wing angle controller 150 so as to be a predetermined set angle with respect to the current wing angle, so that wing angle control is performed.

The wing angle control unit 150 has a separate power supply device, but the above-described operation is possible even when the system power is lost, but the yaw angle control unit 160 does not have a separate power supply device. Therefore, the step of allowing power supply to be made prior to the command transmission must be preceded.

In operation S220, the first switch 170 that is in charge of the connection with the system 120 is turned off, and the second switch 175 that is in connection with the power converter 130 is turned on to input the yaw angle controller 160. Change the power. The first switch 170 is turned off to disconnect the grid 120, and the second switch 175 is turned on to establish a connection with the DC link 134 of the power converter 130. That is, the yaw angle control unit 160 is driven by using the power generated by the current generator instead of the system power that is expected to occur.

In step S230, the system control unit 140 performs yaw angle control in the stop direction to rotate the tower top (nacelle) to a predetermined angle (for example, 90 degrees) with respect to the main wind direction to minimize the influence of the wind. .

The system controller 140 calculates the yaw motor change angle for yaw angle control. The yaw motor change angle is the difference angle between the current yaw angle and the angle to minimize the wind angle. The wind angle angle minimum angle may be, for example, an angle that is rotated 90 degrees clockwise (or counterclockwise) with respect to the main wind direction.

By performing wing angle control (step S210) and yaw angle control (step S230), the blade angle control as well as yaw angle control (yawing) as well as blade angle control of the blade in an emergency operation state (for example, LVRT situation or system accident situation). Can be reduced simultaneously to reduce the input energy to the wind power system.

In operation S240, the system controller 140 determines whether the system power is restored within a preset time.

When the system power is restored, the process proceeds to step S242 and the system controller 140 recognizes the current wind power generation system situation as an LVRT situation.

In the LVRT situation, since the system power is quickly restored, the input power line to the yaw angle control unit 160 is changed back to the system power in step S244. To this end, the first switch 170 is turned on and the second switch 175 is turned off.

Thereafter, in step S246, the system controller 140 performs yaw angle control so that the yawing motion occurs in the power generation direction. That is, the tower top (nacelle) is moved to the main wind direction to be placed in parallel with the main wind direction so that the wind angle is maximized to achieve a smooth power generation.

Thereafter, the process proceeds to step S300, and the system controller 140 operates the power generation system 1 in the automatic operation mode. In the automatic operation mode, the system control unit 140 generates a command for optimal generation efficiency while following the wind corresponding to predetermined measurement data, and outputs the command to the corresponding component to output the rotation angle (yaw angle) of the tower and the blade. It means the driving mode to control the wing angle. Here, the measurement data includes wind speed data, generator rotational speed (e.g., RPM), system operating status, grid power properties (grid voltage (Vgrid), grid current (Igrid), grid frequency (Fgrid), power factor, etc.), and the like. The command may be at least one of a yaw angle, a torque reference, a wing angle, and the like.

As a result of the determination in step S240, when the system power is not restored, in step S250, the system controller 140 recognizes the current wind power generation system status as a grid power loss situation.

The generator operation is stopped in step S260, and waits until the system power is restored in step S270.

When the system power is restored, the system control unit 140 operates the wind power generation system 100 in the initial operation mode in step S280. The initial operation mode is an operation mode for starting the wind power generation system 100 in a completely stopped state, and performs an internal inspection of the system, and changes the vane angle control unit 150 and the power converter 130 to the initial operation state. . And the blade angle of the blade can be changed from the angle at which the current hit angle area is the minimum angle (for example, 0 degrees) the maximum wind angle area.

In step S290, the input power line to the yaw angle control unit 160 is changed to a system power source. To this end, the first switch 170 is turned on and the second switch 175 is turned off.

Subsequently, the process proceeds to step S300, and the system controller 140 operates the wind power generation system 100 in the automatic driving mode.

According to the operating method of the wind power generation system according to the present embodiment, when the power supply is lost in the rated operation of the wind power generator, the switch (first switch) connected to the grid side is cut off to reduce the input energy received by the wind power generation system. The yaw motor is driven by connecting a switch (second switch) connected to the converter, and the yaw angle control unit is driven together with the wing angle control unit so that the blade and nacelle rotate simultaneously to minimize the wind angle. Will be reduced.

However, in the case of LVRT, when the grid power is restored, the switch (second switch) connected to the power converter is cut off and the switch (first switch) connected to the grid side is connected to adjust the angle of the blade and nacelle. The area is maximized to maximize the amount of input energy.

Through this, the stability of power converter and wind power generation system can be increased, and more stable system operation is possible by maximizing power generation.

The subject in each step in the method of operating the wind power generation system in the emergency operation illustrated in FIG. 3 is not limited to each component illustrated in FIG. 2, and may be interpreted as a wind power generation system according to an embodiment of the present invention. .

It is natural that the method of operating the wind power generation system in the emergency operation state described above with reference to FIG. 3 may be performed in an automated procedure according to a time series sequence by a program embedded in or installed in an output control device of the wind power generation system. The codes and code segments that make up the program can be easily deduced by a computer programmer in the field. In addition, the program is stored in a computer readable medium readable by the digital processing apparatus, and is read and executed by the digital processing apparatus to implement the method. The information storage medium includes a magnetic recording medium, an optical recording medium, and a carrier wave medium.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the following claims And changes may be made without departing from the spirit and scope of the invention.

100: wind power generation system 110: generator
120: system 130: power converter
132: generator side converter 134: DC link
136: grid-side converter 140: system control
150: wing angle control unit 160: yaw angle control unit
165: yaw drive unit 170: first switch
175: second switch

Claims (8)

Wind power generation system that controls the blade angle and yaw angle of the blade in the emergency operation state,
A power conversion device connected between the generator and the grid and transferring the power generated by the generator to the grid;
According to the control signal to drive the blade blade angle control motor to perform the wing angle control, in the emergency operation state wing angle control unit receives the operating power from the battery;
A yaw angle control unit configured to drive a yaw motor according to a control signal to perform yaw angle control;
A yaw driver connected to the system via a first switch, and connected to the power converter through a second switch, and supplying operation power to the yaw angle controller; And
And a system controller for controlling an opening and closing operation of the first switch and the second switch according to an operating state of the wind power generation system to supply operating power to the yaw angle controller. The method of claim 1,
And the system controller turns off the first switch and turns on the second switch in an emergency operation state such that the power stored in the power converter is the input power of the yaw angle controller. 3. The method of claim 2,
The system control unit generates a control signal for changing the wing angle and yaw angle so that the wind hit angle area of the blade to the minimum in the emergency operation state and outputs to the wing angle control unit and the yaw angle control unit, respectively. The method of claim 1,
The emergency operation state is a wind power generation system is a LVRT (Low Voltage Ride Through) situation or a system accident situation. A method of operating a wind power generation system in which the system controller controls the blade angle and yaw angle of a blade in an emergency operation state,
(a) controlling the vane angle to a stop angle when system power is lost;
(b) changing the input power of the yaw driver to the power of the power converter from the system power; And
and (c) controlling the yaw angle in a stop direction. 6. The method of claim 5,
(d) determining whether the system power is restored within a predetermined time;
(e) Recognizing and processing as a Low Voltage Ride Through (LVRT) situation when recovered, and processing and recognizing as a system accident situation if not recovered. The method according to claim 6,
In the case of recognizing the LVRT situation, step (e) may include:
(e1) changing the input power of the yaw driver from the power of the power converter to the system power;
(e2) a method of operating a wind power generation system in an emergency operation state comprising controlling the yaw angle in the direction of generation. The method according to claim 6,
If it is recognized that the system accident situation, step (e),
(e1) stopping generator operation until the system power is restored;
(e2) after the system power is restored, converting the input power of the yaw driving unit from the power of the power converter to the system power after switching the system to an initial operation mode; Driving way.

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