KR102175913B1 - Wind turbine system and method for controlling the same - Google Patents

Abstract

The present invention provides a wind power generation system and a control method thereof that can efficiently use an installation space, reduce installation cost, increase the lifespan of an ESS, and increase energy storage efficiency.
A wind power generation system according to an aspect of the present invention includes a wind turbine, a main ESS connected between the wind generator and a power grid, a sub ESS provided in the wind generator and selectively connected to the main ESS or the power grid, and the sub It includes a control unit that controls charging and discharging of ESS and main ESS.

Description

Wind power generation system and its control method {WIND TURBINE SYSTEM AND METHOD FOR CONTROLLING THE SAME}

The present invention relates to a wind power generation system and a control method thereof, and more particularly, to a wind power generation system including an ESS and a control method thereof.

Wind power generation refers to a power generation method that converts wind energy into mechanical energy (rotation power) using a windmill, and this mechanical energy is converted into electrical energy by driving a generator to obtain power.

Wind power is the most economical among new renewable energy sources developed so far, and because of the advantage of being able to generate electricity using wind, which is an infinite, no-cost clean energy source, active investment is being made in Europe as well as the Americas and Asia. to be.

Renewable energy sources, such as wind power generation or solar power generation, essentially have intermittent characteristics in which the amount of power produced varies greatly depending on environmental factors such as season and weather. Such intermittentness causes rapid fluctuations in power generation output, resulting in poor power quality. As a classic method for overcoming such intermittentness, instead of installing a single device with a high capacity, multiple devices with a low capacity are installed, or a method of distributing power generation facilities over a wide area has been applied.

Recently, power produced from a renewable energy source is stored in an energy storage system (ESS) and used when needed, thereby expanding new and renewable energy and enhancing the efficiency of the power industry.

The energy storage system (ESS) is composed of various operating systems such as power storage sources, power conversion devices (PCS), and power management systems (PMS).

Among them, the power management system controls the ESS and is very important to improve power quality and optimize energy efficiency by efficiently operating power storage sources and power conversion devices developed so far.

Korean Patent Registration No. 10-1141047

An object of the present invention is to provide a wind power generation system capable of efficiently using an installation space and reducing installation cost by efficiently arranging a wind power generator and an energy storage system.

In addition, the present invention is to provide a control method of a wind power generation system capable of increasing the lifespan of the ESS and increasing energy storage efficiency by efficiently controlling the charging and discharging of the ESS according to the generation power and load power.

A wind power generation system according to an aspect of the present invention includes a wind turbine, a main ESS connected between the wind generator and a power grid, a sub ESS provided in the wind generator and selectively connected to the main ESS or the power grid, and the sub It may include a control unit that controls charging and discharging of the ESS and the main ESS.

The control unit may control to supply and store power generated by the wind turbine to the sub ESS, and to supply and store power to the main ESS when there is remaining power.

The control unit may control the power generated by the wind turbine to be supplied to the sub-ESS to store and supply power to the power grid when there is no remaining power.

A plurality of wind turbines are installed and each sub-ESS is connected, and the main ESS may be connected to each sub-ESS.

The sub ESS may be stacked and installed inside the tower of the wind turbine.

The sub ESS may be composed of a lithium secondary battery.

A method of controlling a wind power generation system according to another aspect of the present invention is a control method of a wind power generation system including a wind power generator, a sub ESS provided in the wind power generator, and a main ESS connected between the sub ESS and a power grid. , Charging the sub-ESS by supplying power generated from the wind turbine to the sub-ESS, and charging the sub-ESS by supplying the power to the main ESS when there is power remaining compared to the load.

It may further include the step of supplying and charging the power generated by the wind turbine to the sub-ESS, and supplying power from the sub-ESS to the power grid when there is no remaining power compared to the load.

The sub ESS may be stacked and installed inside the tower of the wind turbine.

A plurality of wind turbines are installed and each sub-ESS is connected, and the main ESS may be connected to each sub-ESS.

The sub ESS may be composed of a lithium secondary battery.

As described above, according to an aspect of the present invention, by efficiently arranging the wind power generator and the energy storage system, it is possible to efficiently use the installation space and reduce the installation cost.

In addition, by efficiently controlling the charging and discharging of the ESS according to the magnitude of the power generation and the load power, it is possible to increase the lifespan of the ESS and increase energy storage efficiency.

1 is a schematic diagram showing a wind power generation system according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing that power is directly supplied from the sub ESS to the power grid in the wind power generation system of FIG. 1.
3 is a view showing that the sub-ESS is installed inside the tower of the wind turbine.
4 is a flow chart showing a control method of the wind power generation system according to an embodiment of the present invention.

The present invention is intended to illustrate specific embodiments and to be described in detail in the detailed description, since various transformations can be applied and various embodiments can be provided. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all conversions, equivalents, and substitutes included in the spirit and scope of the present invention.

The terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present invention, terms such as'comprise' or'have' are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this case, it should be noted that in the accompanying drawings, the same components are indicated by the same reference numerals as possible. In addition, detailed descriptions of known functions and configurations that may obscure the subject matter of the present invention will be omitted. For the same reason, some components in the accompanying drawings are exaggerated, omitted, or schematically illustrated.

Hereinafter, a wind power generation system according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

1 is a schematic diagram showing a wind power generation system according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing that power is directly supplied to the power grid from the sub-ESS in the wind power generation system of FIG. 1, and FIG. 3 is a wind turbine It is a diagram showing that the sub ESS is installed inside the tower of.

A wind power generation system according to an embodiment of the present invention includes a wind power generator 10, a sub ESS 20, a main ESS 30, and a control unit.

The wind turbine 10 includes a tower 12, a nacelle 14, and a plurality of blades 16. The tower 12 is installed standing at a certain height from the ground, and may support the nacelle 14 and a plurality of blades 16. The tower 12 may have a tubular shape whose diameter increases from the top to the bottom. Inside the tower 12, stairs, conveyors, or elevators may be installed to transport workers or work tools for maintenance of the generator.

The nacelle 14 is a housing installed on the top of the tower 12, and is generally formed in a hexahedral shape, but may be formed in a cylindrical shape or the like. Inside the nacelle 14, a shaft (not shown), a gearbox (not shown), a brake (not shown), a generator (not shown), and the like may be installed.

A hub (not shown) coupled to the front end of the shaft is rotatably installed in front of the nacelle 14. A plurality of blades 16 are coupled to the outer peripheral surface of the hub so as to be spaced apart from each other at predetermined intervals along the circumferential direction.

The hub can be made of a conical protruding convexly forward to reduce wind resistance. The blade 16 rotates about the central axis of the hub by the wind. The blade 16 has a streamlined cross section in the width direction, and a space portion may be formed therein.

The shaft transmits the rotational force of the rotor composed of the hub and the plurality of blades 16 to the gearbox. The shaft can be rotatably supported by bearings.

The gearbox is a device that converts the rotational speed of a shaft rotated by the rotor to a suitable rotational speed by using a gear, and an increaser gear unit including a plurality of gears may be provided inside the gearbox. In addition, oil for a speed increaser may be provided in the speed reducer for lubrication and cooling of a plurality of gears in the speed increase gear part.

The brake can be placed adjacent to the gearbox to control the torque of the shaft. This brake can mainly use the disc method.

A generator is a device that generates power using input rotational energy, and includes a rotor and a stator connected to a rotating shaft therein. Electric power is generated by the rotor rotating at high speed around the stator.

The sub ESS (20) is installed adjacent to each wind turbine (10) to receive and charge the power produced by each wind turbine (10) and discharge the power if necessary.

The main ESS 30 is connected between the sub ESS 20 and the power grid 50, and a plurality of sub ESSs 20 are connected to the main ESS 30. The main ESS 30 may receive power from the sub ESS 20 and charge it or discharge it to supply power to the power grid 50.

Charging and discharging of the sub ESS 20 and the main ESS 30 are controlled by a control unit (not shown). The control unit charges the sub ESS 20 by first supplying the electric power produced by the wind turbine 10 to the sub ESS 20. When the sub ESS 20 is fully charged, the control unit controls to supply power to the main ESS 30 or the power grid 50. The control unit may control the sub-ESS 20 to supply power to the power grid 50 when a power load occurs even when the sub-ESS 20 is not fully charged.

Energy Storage System (ESS) is a system that maximizes energy efficiency by storing generated power in each connected system including power plants, substations, and transmission lines, and then selectively and efficiently using power when power is needed. to be.

When using ESS, it is possible to achieve load leveling in response to environmental changes, especially for charging and discharging of renewable energy power. In addition, the smart grid ESS can build a two-way power supply system using information and communication technology, improve the flexibility of the transmission and distribution power system, prevent power outages, and improve the efficiency of power management in economic terms. have.

Looking at the type of ESS by storage capacity, a large-capacity ESS is located on a power plant, has a capacity of several hundred MW, and can store power for several hours every day. The small-capacity ESS is placed on the transmission/distribution point and is directly connected to the power consumer. The capacity is kW and can store power in units of minutes.

Power storage devices for storing power used in ESS include lithium secondary batteries, redox flow batteries, NaS (sodium-sulfur) batteries, and compression in addition to pumped hydro. Compressed Air Energy Storage and flywheel batteries.

Pump and flywheel batteries are physical energy storage systems that can quickly store high-power energy.

Li-Z secondary batteries, NaS batteries, and redox flow batteries are chemical energy storage systems. In particular, Li-Z secondary batteries and NaS batteries can be suitably used for both power plants and consumer ESSs.

In particular, the LiZ secondary battery has a power conversion efficiency of 96%, a lifespan of close to 10 years, and a discharge duration of about 15 minutes to 2 hours. LiZ secondary batteries are easy to commercialize, eco-friendly, and have excellent efficiency.

In the present invention, both the sub ESS 20 and the main ESS 30 may be configured with the same type of battery. For example, the sub ESS 20 and the main ESS 30 may be composed of a Li?Z secondary battery. On the other hand, the sub ESS 20 and the main ESS 30 may be configured with different types of batteries. In this case, the capacity of the main ESS 30 may be larger than the capacity of the sub ESS 20.

The wind power generation system of the present invention can reduce the size of the main ESS by installing sub ESSs in each wind power generator in addition to the main ESS. Accordingly, the installation area and space for installing the main ESS can be reduced, and the system installation space can be efficiently utilized. In addition, as the generated power is distributed and stored in the main ESS or the sub ESS, the generated power can be efficiently stored and used.

The controller supplies and stores the power produced by the wind turbine 10 to the sub ESS 20, and controls to supply and store power to the main ESS 30 when there is remaining power.

The power produced by the wind turbine 10 varies over time, and the load power required by the power grid 50 may also vary over time. The control unit supplies the power produced by the wind turbine 10 to the sub ESS 20 for charging, and, if there is power remaining against the load power, supplies power to the main ESS 30 as shown in FIG. Thus, the main ESS 30 is controlled to be charged. The controller may control the power grid 50 to discharge power from the main ESS 30 and supply it to the power grid 50 when a necessary load is generated. Of course, if a required load is present in the power grid 50, the control unit may control to supply power to the main ESS 30 to charge and supply power from the main ESS 30 to the power grid 50 at the same time. .

The control unit supplies and stores the power generated by the wind turbine 10 to the sub ESS 20 and controls to supply power from the sub ESS 20 to the power grid 50 as shown in FIG. 2 when there is no remaining power. do. In this case, since the load power is large and there is not enough power left to charge the main ESS 30 even though the generated power is supplied to the power grid 50, the control unit directly supplies power from the sub ESS 20 to the power grid 50. To be controlled. Of course, when the sum of the generated power and the charged power of the sub ESS 20 is less than the load power, the control unit discharges the power charged in the sub ESS 20 together with the generated power to the power grid 50 together with the generated power. Can be controlled to supply.

In addition, when the generated power is less than the load power, the power previously charged in the main ESS 30 may be controlled to be supplied to the power grid 50. Accordingly, even if the generated power fluctuates in real time, power can be stably supplied to the power grid 50.

On the other hand, a plurality of wind turbines 10 (10-1. 10-2, 10-3, 10-4) are installed, and each sub ESS (20-1, 20-2, 20-3, 20-4) is It is connected, and the main ESS 30 may be connected to each sub ESS (20-1, 20-2, 20-3, 20-4).

1 and 2, four wind turbines (10-1. 10-2, 10-3, 10-4) are installed, and sub ESSs (20-1, 20-2, 20-3, 20) are installed in each wind turbine. An embodiment in which -4) is connected is shown. The number of wind turbines may be 1 to dozens depending on the site situation, and one or more sub-ESSs may be connected to each wind turbine.

In the case of an embodiment in which a plurality of wind turbines (10-1. 10-2, 10-3, 10-4) and a plurality of sub ESSs (20-1, 20-2, 20-3, 20-4) are connected, each Since the generated power of the wind turbine is different from each other, where the power is supplied from each sub-ESS (20-1, 20-2, 20-3, 20-4) can be controlled differently.

For example, in a state in which a predetermined load power currently exists, the sum of the generated power of the three wind turbines 10-1, 10-2, and 10-3 is produced larger than the load power, and one wind turbine ( 10-4) is, when no power is produced, the generated power is supplied to each sub ESS (20-1, 20-2, 20-3), followed by the main ESS (30), and at the same time, the remaining power is supplied to the power grid (50 ) Can be supplied.

If the sum of the generated power of the three wind turbines (10-1, 10-2, 10-3) is less than the load power, the generated power is transferred to each sub ESS (20-1, 20-2, 20-3). It can be supplied and then supplied directly to the power grid 50.

As shown in FIG. 3, the sub ESS 20 is preferably installed by being stacked inside the tower 12 of the wind turbine 10.

As described above, stairs, conveyors, elevators, etc. are installed inside the tower 12, and the sub ESS 20 may be stacked and installed so as not to interfere with stairs, conveyors, or elevators.

In this case, an air-cooled cooling device (not shown) for blowing air at room temperature to the sub ESS 20 that generates heat during charging and discharging by a driving force of a shaft rotated by wind power may be provided. A water cooling type cooling device may be provided for cooling the sub ESS 20 with cooling water by driving the pump with the driving force.

It is preferable that the sub ESS 20 is composed of a lithium secondary battery. The sub ESS (20) is an energy storage device having a smaller capacity than the main ESS (30), and it is advantageous to install inside the tower 12 because it has good power conversion efficiency and is easy to miniaturize when configured with a lithium secondary battery.

A lithium secondary battery is a battery that uses the principle of generating a potential difference as lithium ions move between a positive electrode and a negative electrode, and has advantages of high energy density and energy efficiency.

Next, a control method of the wind power generation system of the present invention will be described with reference to FIG. 4.

As shown in Figure 4, by operating the wind turbine 10 to generate power, that is, to produce power (S10). When the wind blows above a predetermined speed, the blades of the wind turbine will rotate and generate electricity.

When the wind turbine 10 generates power, the generated power is supplied to the sub ESS 20 and charged (S20). Even if power is supplied to the sub ESS 20, if the power is simultaneously discharged, the sub ESS 20 may be charged or discharged depending on the magnitude of the charging power and the discharging power.

At this time, the control unit charges the sub ESS 20 and determines whether there is power remaining relative to the load (S30). Here, the power remaining relative to the load refers to the power remaining after subtracting the load power from the generated power when generating power greater than the load power required by the power grid 50 is produced. In addition, the remaining power is first charged to the sub ESS (20), and if the power remains even after the sub ESS (20) is fully charged, it is supplied to the main ESS (30) for charging.

In step S30, if the sub ESS (20) is charged and there is power remaining compared to the load, the power is supplied from the sub ESS (20) to the main ESS (30) to charge it, and if there is a load, from the main ESS (30). Discharge and supply power to the power grid 50 (S40).

In step S30, when the sub ESS 20 is charged and there is no remaining power compared to the load, power is directly supplied from the sub ESS 20 to the power grid 50 (S50).

According to the present invention, by efficiently arranging the wind turbine generator and the energy storage system, the installation space can be efficiently used and installation cost can be reduced.

In addition, by efficiently controlling the charging and discharging of the ESS according to the magnitude of the power generation and the load power, it is possible to increase the lifespan of the ESS and increase energy storage efficiency.

As described above, one embodiment of the present invention has been described, but those of ordinary skill in the relevant technical field add, change, delete or add components within the scope not departing from the spirit of the present invention described in the claims. Various modifications and changes can be made to the present invention by means of the like, and it will be said that this is also included within the scope of the present invention.

10: wind power generator
12: tower
14: Nacelle
16: blade
20: sub ESS
30: main ESS
50: power grid

Claims (11)

A tower, a nacelle, a plurality of wind turbines including a plurality of blades;
A main ESS connected between the plurality of wind turbines and a power grid;
A plurality of sub-ESSs stacked and installed inside each tower of the plurality of wind turbines and selectively connected to the main ESS or the power grid; And
And a control unit for controlling charging and discharging of the plurality of sub-ESSs and main ESSs,
The control unit supplies and stores power generated by the wind turbine to the sub ESS, and controls to supply and store power to the main ESS when there is remaining power,
The control unit supplies and stores the power generated by the wind turbine generator to the sub-ESS, and controls to supply power to the power grid when there is no remaining power. delete delete delete delete The method of claim 1,
The sub-ESS is a wind power generation system, characterized in that consisting of a lithium secondary battery. A plurality of wind turbines including a tower, a nacelle, and a plurality of blades, a plurality of sub ESSs stacked and installed inside each tower of the plurality of wind turbines, and a main ESS connected between the plurality of sub ESSs and the power grid, respectively. In the control method of the wind power generation system comprising,
Charging by supplying power generated from the wind turbine to the sub-ESS;
Charging the sub ESS and supplying it to the main ESS when there is power remaining relative to the load to charge; And
And supplying the power generated by the wind turbine to the sub-ESS to charge the sub-ESS, and supplying power from the sub-ESS to the power grid when there is no remaining power compared to the load. delete delete delete The method of claim 7,
The sub-ESS is a control method of a wind power generation system, characterized in that consisting of a lithium secondary battery.

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