KR20200108553A - Apparatus for controlling power generator, Apparatus for controlling energy storage system, and Cooperative control system including them - Google Patents

Abstract

The present invention relates to a cooperative control system, a generator control device, and an energy storage system (ESS) control device. Specifically, the present invention relates to a technology for maintaining a frequency of system power through cooperative control between a control device included in a generator and a control device included in an ESS. According to the present invention, the cooperative control system comprises: a generator control device which controls output of a generator based on a frequency difference value between a rated frequency of a power system and a system frequency and a state of charger (SOC) of an ESS; and an ESS control device controlling output of the ESS based on the frequency difference value and a rotational speed of a rotor installed in the generator.

Description

Generator control device, ESS control device, and cooperative control system including the same {Apparatus for controlling power generator, Apparatus for controlling energy storage system, and Cooperative control system including them}

The present disclosure relates to a cooperative control system, a generator control device, and an ESS control device. Specifically, the present disclosure relates to a technology for maintaining the frequency of the system power through cooperative control between the control device included in the generator and the control device included in the ESS.

The frequency of the power system is an important criterion for determining the reliability of the system. When a disturbance such as a generator dropout or an increase in a load occurs in the power system, there is a problem that the frequency of the power grid decreases due to insufficient electric energy.

In order to overcome this problem, control methods for maintaining the frequency of the power system are being developed. As one of them, there is a method of adding a frequency change amount control loop that contributes to frequency control to the existing control loop by multiplying the amount of change in frequency by the droop coefficient.

On the other hand, as the problem of unbalanced power supply and demand intensifies every year, as a method to solve the problem, ESS (Energy Storage System) has recently been in the spotlight. ESS is a system that controls various voltages and currents generated from distributed power or renewable energy, and connects to the power system or stores and uses electrical energy as needed.

Since such new and renewable energy can be supplied irregularly, when the generator and ESS independently maintain the frequency of the system power, there is a problem that the new and renewable energy cannot be efficiently utilized and some loss occurs.

Accordingly, there is a situation in which a technology for continuously operating power generation sources contributing to frequency maintenance within a contributing range and increasing the storage efficiency of new and renewable energy is being developed.

Against this background, the present disclosure is intended to provide a cooperative control system, a generator control device, and an ESS control device capable of stably maintaining the system frequency of the power system by performing cooperative control between the control device of the generator and the control device of the ESS.

In addition, the present disclosure is a cooperative control system that enables stable operation of the generator by performing cooperative control between the control device of the generator and the control device of the ESS, thereby maintaining the rotational speed of the rotor included in the generator within the allowable range. And ESS control device.

In addition, the present disclosure is a cooperative control system that can flexibly adjust the contribution according to the state of each power source while continuously operating within the range that each power source can contribute by performing cooperative control between the generator control device and the ESS control device. , Generator control device and ESS control device.

In addition, the present disclosure aims to provide a cooperative control system, a generator control device, and an ESS control device that minimize the loss of new and renewable energy and maximize the storage efficiency of ESS by performing cooperative control between the generator control device and the ESS control device. .

In order to solve the above-described problem, in one aspect, the present disclosure provides a generator control device for controlling the output of the generator based on the frequency difference value between the rated frequency and the grid frequency of the power system and the output of the ESS based on the frequency difference value. Including a controlling ESS control device, wherein the generator control device receives SOC information on the SOC of the ESS, calculates a first active power gain based on the frequency difference value and the SOC information, and calculates a first active power gain based on the first active power gain. Thus, the output amount or absorption amount of the generator is controlled, and the ESS control device receives speed information on the rotational speed of the rotor provided in the generator, and calculates a second active power gain based on the frequency difference value and speed information, It provides a cooperative control system, characterized in that controlling the amount of output or absorption of the ESS based on the second active power gain.

In another aspect, the present disclosure calculates the frequency difference value by receiving the rated frequency and system frequency of the generator communication unit and power system receiving ESS information from the ESS (Energy Storage System), and is effective based on the frequency difference value and ESS information. It provides a generator control device including a generator control unit that calculates the power gain and controls the output of the generator based on the active power gain.

In another aspect, the present disclosure calculates a frequency difference value by receiving the rated frequency and system frequency of the ESS communication unit receiving generator information from the generator and the power system, and calculating the active power gain based on the frequency difference value and the generator information. And it provides an ESS control device including an ESS control unit that controls the output of the ESS based on the active power gain.

As described above, according to the present disclosure, the present disclosure is a cooperative control system capable of stably maintaining the grid frequency of the power system by performing cooperative control between the control device of the generator and the control device of the ESS, the generator control device and the ESS control. Device can be provided.

In addition, according to the present disclosure, the present disclosure is a cooperative control that enables stable operation of the generator by maintaining the rotational speed of the rotor included in the generator within the allowable range by performing cooperative control between the control device of the generator and the control device of the ESS. System, generator control device and ESS control device can be provided.

In addition, according to the present disclosure, the present disclosure provides cooperative control between the control device of the generator and the control device of the ESS, so that the contribution can be flexibly adjusted according to the state of each power source while continuously operating within the range that each power source can contribute. Cooperative control system, generator control device and ESS control device can be provided.

In addition, according to the present disclosure, a cooperative control system, a generator control device and an ESS control device are provided that minimize the loss of new and renewable energy and maximize the storage efficiency of ESS by performing cooperative control between the generator control device and the ESS control device. can do.

1 is a diagram schematically showing a power system according to the present disclosure.
2 is a block diagram illustrating a generator control apparatus according to the present disclosure.
3 is a flow chart for explaining the operation of the generator control apparatus according to the present disclosure.
4 is a flowchart illustrating an embodiment of controlling a generator by calculating an active power gain according to the present disclosure.
5 is a circuit diagram of an embodiment of a generator control device according to the present disclosure.
6 is a graph showing the power of the generator according to the rotational speed of the rotor.
7 is a block diagram illustrating an ESS control apparatus according to the present disclosure.
8 is a flowchart illustrating the operation of the ESS control apparatus according to the present disclosure.
9 is a flowchart illustrating an embodiment of controlling an ESS by calculating an active power gain according to the present disclosure.
10 is a circuit diagram of an embodiment of an ESS control device according to the present disclosure.
11 is a schematic diagram showing a model of a wind farm for simulating the present disclosure.
12A to 12D are graphs showing execution results for the simulation according to FIG. 11.

Hereinafter, some embodiments of the present disclosure will be described in detail through exemplary drawings. In describing the constituent elements of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, the component may be directly connected or connected to that other component, but another component between each component It should be understood that elements may be “connected”, “coupled” or “connected”.

1 is a diagram schematically showing a power system according to the present disclosure.

Referring to FIG. 1, the power system according to the present disclosure may include a generator 10, an energy storage system (ESS) 20, a grid 30, and the like.

The generator 10 may generate new and renewable energy as electric energy. Specifically, the generator 10 may convert new and renewable energy into kinetic energy and generate electric energy by using the converted kinetic energy. Here, the new renewable energy may mean, for example, wind power (wind energy), water power, marine energy, and the like.

For a specific example with reference to FIG. 1, when the generator 10 is a wind turbine, such a wind turbine includes a rotor, a momentum converter, a power transmission device, a power converter and a generator control device, and the wind turbine is The naturally generated wind power is converted into rotational force, and induction electricity generated by the rotational force is supplied to the consumer (or load), ESS 20, and grid 30.

The generator 10 shown in FIG. 1 is exemplified by a wind power generator, but is not limited thereto, and the generator 10 according to the present disclosure may include all power sources capable of converting kinetic energy into electrical energy. have.

The generator 10 may increase or decrease electrical energy, for example, active power by absorbing or releasing kinetic energy according to changes in new and renewable energy. The generator control device (not shown) included in the generator 10 may control the generator 10 to maintain the frequency of the power system by performing the above-described function.

The ESS 20 may store the produced electrical energy in a storage device such as a battery, and may supply the stored electrical energy or active power to the consumer and the grid 30. The ESS 20 may include a power storage source such as a battery and compressed air, a power conversion device such as a power conversion system (PCS), a power management system, and the like.

The ESS 20 may include an ESS control device (not shown) that controls the ESS 20 to maintain the frequency of the power system in the same manner as the generator control device.

When the frequency of the power system according to the present disclosure fluctuates according to an instantaneous change in demand or disturbance, it may be difficult for the generator 10 and the ESS 20 to supply necessary electric energy. Therefore, as described above, it is important that the generator 10 and ESS 20 maintain the frequency of the power system.

The frequency fluctuation of the power system may fluctuate according to the supply of new and renewable energy, and if the supply of new and renewable energy is insufficient or excessive, it will be difficult for the generator 10 to supply the required electric energy or use part of the new and renewable energy. May be. For example, when wind energy is excessively supplied, the generator 10 does not store all of the wind energy due to the limitation of the generator 10 and transmits a portion of the wind energy.

Therefore, cooperative control between the generator 10 and the ESS 20 is required in order to properly maintain the frequency of the system power supply and efficiently use new and renewable energy.

Hereinafter, cooperative control between the generator control device included in the generator 10 and the ESS control device included in the ESS 20 will be described in detail. However, for convenience of explanation, the generator 10 of the present disclosure will be described as being a wind power generator.

2 is a block diagram for explaining the generator control apparatus 100 according to the present disclosure.

Referring to FIG. 2, the generator control apparatus 100 according to the present disclosure may include a generator communication unit 110 and a generator control unit 120.

The generator communication unit 110 may communicate with the ESS 20. Specifically, the generator communication unit 110 receives a receiving module for receiving ESS information, which is information about the ESS 20, from a communication unit (not shown) included in the ESS 20, and generator information, which is information about the generator 10. It may include a transmission module that transmits to the ESS (20).

Here, the ESS information may include information on a storage of charge (SOC), information on a loop gain for controlling the output of the ESS 20, and the like.

Here, the generator information may include information on a rotation speed of a rotor provided in the generator 10, information on a loop gain for controlling the output of the generator 10, and the like.

The generator communication unit 110 may use wireless or wired communication, and may use IEEE 802.11p communication technology using a 5.9 GHz band, but is not limited thereto, and it is understood that it includes all communication to be developed in the present or in the future. Should be.

The generator control unit 120 receives the rated frequency and system frequency of the power system of the generator 10 and calculates a frequency difference value, calculates an active power gain based on the frequency difference value and ESS information, and calculates an active power gain based on the active power gain. Thus, the output of the generator 10 can be controlled.

Here, the rated frequency may mean a designated frequency of AC power supplied from the generator 10 or the power generation complex. The system frequency may mean a frequency of a system acquired through a sensor included in the generator 10 or a central control device that monitors the generator 10.

Meanwhile, the active power gain may mean a gain of a loop for controlling the output of the generator 10. For example, the active power gain refers to the gain or droop coefficient of droop control, and the generator 10 outputs greater power as the frequency difference value is less than zero and the frequency difference value increases in the negative (-) direction. In order to do this, the active power gain, which is the gain of the droop control, is further increased, and the frequency difference value is greater than zero, and as the frequency difference value increases in the positive (+) direction, the generator 10 absorbs more power and In order to absorb kinetic energy, the active power gain is further increased.

When the active power gain is the gain of the droop control, the generator control unit 120 controls the output of the generator 10 by performing droop control, but adjusts the gain of the droop control using the frequency difference value and ESS information. I can.

The generator control unit 120 calculates a frequency difference value, which is a difference value obtained by subtracting the rated frequency from the system frequency, calculates the sign and size of the active power gain according to the sign and size of the frequency difference value, and ESS information, and the characteristics of the active power. Depending on (sign, size, etc.), the output amount of power produced by the generator 10 may be controlled, or the amount of absorbed power or the amount of kinetic energy may be controlled.

When the frequency difference value is greater than zero, it means that the amount of supply is greater than the amount of demand. Therefore, the generator control unit 120 absorbs the excessively supplied active power and absorbs the kinetic energy. The amount of energy absorption can be controlled. In this case, the amount of output for the power of the generator 10 reflectively decreases.

Conversely, when the frequency difference value is less than zero, it means that the amount of demand is greater than the amount supplied, so that the generator control unit 120 can control the output amount of the power of the generator 10 so that the generator 10 additionally outputs power. .

Meanwhile, the generator control unit 120 may receive a rotational speed of a rotor provided in the generator 10 and calculate an active power gain based on the rotational speed. Details will be described later with reference to FIG. 3.

3 is a flow chart for explaining the operation of the generator control apparatus 100 according to the present disclosure.

3, the generator control apparatus 100 according to the present disclosure receives a rated frequency (f _nom ) and a system frequency (f _sys ) (S310), and calculates a frequency difference value (Δf) (S311).

For example, the generator control unit 120 calculates a frequency difference value (Δf) by subtracting the rated frequency (f _nom ) from the system frequency (f _sys ).

Meanwhile, the generator control apparatus 100 according to the present disclosure receives ESS information from the ESS 20 (S320). Then, the generator control apparatus 100 according to the present disclosure calculates the active power gain K _w of the generator 10 by using the frequency difference value Δf and ESS information (S330).

For example, the generator communication unit 110 receives ESS information including SOC information on the SOC of the ESS 20 and outputs the ESS information to the generator control unit 120. The generator control unit 120 obtains the SOC using the SOC information, and calculates or adjusts the active power gain K _w according to the frequency difference value Δf and the SOC.

Here, the reason for using the SOC of the ESS 20 when the generator control unit 120 calculates the active power gain K _w is as follows.

When the SOC is relatively small in a situation in which power is absorbed, the generator control device 100 relatively reduces the absorption amount of the generator 10 in order for the ESS 20 to store more electrical energy, and conversely, the SOC is relatively small. If it is large, the generator control device 100 is to relatively increase the absorption amount of the generator 10 in consideration of the electric energy storage limit of the ESS 20.

On the other hand, when the SOC is relatively small in a situation where power is supplied, the generator control device 100 relatively increases the output amount of the generator 10 in consideration of the electric energy supply limit of the ESS 20, and conversely, the SOC is In a relatively large case, the generator control device 100 is for relatively reducing the output amount of the generator 10 in order for the ESS 20 to supply more electric energy to the consumer.

On the other hand, the generator control device 100 according to the present disclosure receives the rotational speed (ω _r ) of the rotor provided in the generator (S340), and calculates the driving equipment ratio (r) using the rotational speed (ω _r ). And, the active power gain (K _w ) is calculated or adjusted by reflecting the driving supplement ratio (r) (S330).

For example, the generator control unit 120 calculates the driving compensation rate (r) using the rotation speed (ω _r ), the preset rated rotation speed (ω _rated ), and the minimum value (ω _min ) of the rotation speed, and guarantees operation. By reflecting the ratio (r), the active power gain (K _w ) is calculated.

Here, the driving maintenance ratio r may mean a ratio that ensures that the generator 10 can operate stably. This is because when the rotational speed (ω _r ) of the rotor is reduced below the minimum value, the generator 10 stops operating. This driving gear ratio (r) can be calculated by the following [Equation 1].

[Equation 1]

When the active power gain (K _w ) of the generator 10 is calculated, the generator control device 100 according to the present disclosure controls the output of the generator 10.

For example, when the frequency difference value Δf is less than zero, the generator control unit 120 increases or decreases the output amount of power produced by the generator 10 based on the active power gain K _w . Conversely, when the frequency difference value Δf is greater than zero, the amount of absorption of power produced by the generator 10 is increased or decreased based on the active power gain K _w .

Hereinafter, an embodiment of controlling the generator 10 by calculating the active power gain K _w according to the SOC according to the present disclosure will be described in detail.

4 is a flowchart illustrating an embodiment of controlling the generator 10 by calculating an active power gain according to the present disclosure.

Referring to FIG. 4, in step S411, the frequency difference value Δf is calculated by subtracting the rated frequency f _nom from the system frequency f _sys , and in step S412, SOC information included in the received ESS information is obtained.

Then, in step S421, it is determined whether the frequency difference value Δf is greater than zero. If the frequency difference value Δf is not greater than zero, in step S422, it is determined whether the frequency difference value Δf is less than zero.

If the frequency difference value Δf is greater than zero, in step S431, the active power gain _Kw is calculated using the frequency difference value Δf and the SOC. At this time, the active power gain (K _w ) is determined in proportion to the SOC. The reason is that, as described above, excess supply, so state higher the SOC of ESS (20) in reducing the stored energy absorption capacity of the ESS (20), the effective power gain in order to increase the absorption of the generator (10) (K _w ) Has to be increased further.

Accordingly, when the frequency difference value Δf is greater than zero, the generator control unit 120 may calculate an active power gain K _w in proportion to the SOC.

The Next, in step S441 controls the absorption of the generator 10 on the basis of the effective power gain (K _w).

On the other hand, if the frequency difference value (Δf) is less than zero, in step S432, the active power gain (K _w ) is calculated using the frequency difference value (Δf) and the SOC, but the active power gain (K _w ) is inversely proportional to the SOC. Is determined. The reason is, as described above, as the SOC of the ESS 20 decreases in a situation where the supply of electric energy is insufficient, the storage energy supply capacity of the ESS 20 decreases, so it is effective to increase the output amount of the generator 10. This is because the power gain (K _w ) needs to be further increased.

Therefore, when the frequency difference value Δf is less than zero, the generator control unit 120 may calculate an active power gain in inverse proportion to the SOC.

Then, in step S442, the output amount of the generator 10 is controlled based on the active power gain K _w .

On the other hand, when the frequency difference value Δf is zero, the output of the generator 10 may be maintained in step S443.

According to the above, the generator control device 100 according to the present disclosure performs cooperative control with the ESS control device and maintains the frequency by fluidly adjusting the output amount or the absorption amount of the generator 10 according to the SOC of the ESS 20. It provides the effect of supplying electric energy efficiently.

5 is a circuit diagram of an embodiment of the generator control apparatus 100 according to the present disclosure.

Referring to FIG. 5, the generator control apparatus 100 according to the present disclosure may be implemented by designing a circuit for performing droop control. Here, the generator control device 100 performing droop control receives the rated frequency (f _nom ) and the system frequency (f _sys ), and calculates a frequency difference value (Δf).

And, the generator control device 100 calculates the gain (K _w ) of the droop control by using the frequency difference value (Δf) and the SOC received from the ESS 20 and the driving equipment ratio (r), and the frequency difference value ( The active power of the generator 10 is controlled by summing the value obtained by multiplying Δf) by the gain (K _w ) of the droop control and the maximum power point tracking (MPPT) value (P _MPPT ) of the generator 10 Calculate the reference value (P _ref ) of active power to be used.

Then, the rotor converter controller (RSC controller) of the generator control device 100 may adjust the amount of power output from the generator 10 to the power system using the reference value P _ref of active power.

6 is a graph showing the power of the generator 10 according to the rotational speed of the rotor.

Referring to FIG. 6, the blue solid line means the mechanical power (P _mech ) of the generator 10, the red solid line means the MPPT value (P _MPPT ) of the active power of the generator 10, and the green dotted line is the figure. It means the reference value (P _ref ) of the active power shown in 5.

At this time, the relationship between P _mech and P _MPPT and the rotational speed (ω _r ) of the rotor is as shown in [Equation 2] below.

[Equation 2]

That is, if P _mech and P _MPPT are the same, the rotational speed (ω _r ) of the rotor is maintained, and when the system frequency (f _sys ) increases, the rotational speed of the rotor (ω _r ) decreases as P _MPPT decreases. As it increases, the kinetic energy of the rotor is absorbed, and when the system frequency (f _sys ) decreases, P _MPPT increases and the speed of the rotor decreases to release the kinetic energy of the rotor.

On the other hand, when the rotational speed (ω _r ) of the rotor reaches the maximum value (ω _max ), the output point is a point where the graph of mechanical power (P _mech ) meets. At this time, if the output is increased, the kinetic energy of the rotor is released, and accordingly, the rotational speed (ω _r ) of the rotor is decreased, so that it moves to the left again.

According to the foregoing, the generator control apparatus 100 according to the present disclosure provides an effect of more stably operating the generator 10 by adjusting the rotational speed ω _r of the rotor.

Hereinafter, an ESS control device for performing cooperative control between the generator 10 and the ESS 20 will be described in detail.

7 is a block diagram illustrating an ESS control apparatus 200 according to the present disclosure.

Referring to FIG. 7, the ESS control device 200 according to the present disclosure includes an ESS communication unit 210 and an ESS control unit 220.

The ESS communication unit 210 is capable of communicating with the generator 10. Specifically, the ESS communication unit 210 generates a receiving module for receiving generator information, which is information about the generator 10, from the generator communication unit 110 included in the generator control device 100, and ESS information, which is information about ESS. It may include a transmission module that transmits to 10).

Here, the generator information and the ESS information are as described above with reference to FIG. 2, and the ESS communication unit 210 can also use wireless or wired communication in the same way as the generator communication unit 110, but is not limited thereto, It should be understood to include all communications to be developed.

The ESS control unit 220 receives the rated frequency and system frequency of the power system, calculates a frequency difference value, calculates an active power gain based on the frequency difference value and generator information, and calculates the output of the ESS based on the active power gain. Can be controlled.

Here, the rated frequency and the system frequency are the same as described above with reference to FIG. 2, and the active power gain may mean the gain of the loop for controlling the output of the ESS 20. For example, the active power gain is droop. It refers to the gain or droop factor of the control.

On the other hand, as the frequency difference value is smaller than zero and the frequency difference value increases in the negative (-) direction, the active power gain increases further in order for the ESS (20) to output greater power and electrical energy, and the frequency difference value increases. It is greater than zero, and as the frequency difference value increases in the positive (+) direction, the active power gain may be further increased so that the ESS 20 more absorbs electrical energy.

When the active power gain is the gain of the droop control, the ESS control unit 220 controls the output of the ESS by performing droop control, but may adjust the gain of the droop control using the frequency difference value and generator information.

The ESS control unit 220 calculates a frequency difference value that is a difference value obtained by subtracting the rated frequency from the system frequency, calculates the sign and size of the active power gain according to the sign and size of the frequency difference value and the generator information, and the characteristics of the active power. Depending on (code, size, etc.), it is possible to control the amount of electrical energy or power output or absorption of the ESS (20).

That is, if the frequency difference value is greater than zero, it means that the supply amount is greater than the demand amount, so the ESS control unit 220 can control the absorption amount of the ESS (20) power so that the ESS (20) absorbs excess active power. have.

Conversely, when the frequency difference value is less than zero, it means that the amount of demand is greater than the amount of supply, so the ESS control unit 220 may control the amount of power output of the ESS 20.

Meanwhile, the ESS control unit 220 may receive the SOC of the ESS 20 and calculate an active power gain according to the SOC. Details will be described later with reference to FIG. 8.

8 is a flowchart illustrating an operation of the ESS control apparatus 200 according to the present disclosure.

8, the ESS control apparatus 200 according to the present disclosure receives a rated frequency (f _nom ) and a system frequency (f _sys ) (S810), and calculates a frequency difference value (Δf) (S811).

For example, the ESS control unit 220 calculates a frequency difference value (Δf) by subtracting the rated frequency (f _nom ) from the system frequency (f _sys ).

Meanwhile, the ESS control device 200 according to the present disclosure receives generator information from the generator 10 (S820). Then, the generator control unit 100 in accordance with the present disclosure is to calculate the effective power gain (K _e) of the ESS (20) using the difference value (Δf) and the generator frequency information (S830).

For example, the ESS communication unit 210 receives generator information including speed information about the rotational speed (ω _r ) of the rotor provided in the generator 10 and outputs the generator information to the ESS control unit 220. The ESS control unit 220 obtains the rotational speed (ω _r ) of the rotor provided in the generator 10 by using the speed information, and the frequency difference value (Δf) and the rotational speed of the rotor provided in the generator 10 Calculate or adjust the active power gain (K _e ) according to (ω _r ).

Here, the reason for calculating the active power gain (K _e ) based on the rotational speed (ω _r ) of the rotor provided in the generator 10 by the ESS control unit 220 is as follows.

In a situation where power is absorbed, the ESS control unit 220 further increases the absorption amount of the ESS 20 so that the rotational speed (ω _r ) of the rotor provided in the generator 10 increases and does not reach the maximum value. The ESS control unit 220 is to further increase the output amount of the ESS 20 so that the rotational speed ω _r of the rotor provided in the generator 10 is gradually reduced and does not reach the minimum value in this supplied situation.

On the other hand, ESS control unit 220 receives the SOC of ESS (20), calculates an effective power gain (K _e) on the basis of the SOC.

For example, can reduce the effective power gain (K _e) as the SOC is gradually increased from the initial SOC when the frequency difference (Δf) is greater than zero, ESS controller 220. In contrast, when the frequency difference (Δf) is smaller than zero, ESS controller 220 may reduce the effective power gain (K _e) as the SOC is gradually reduced from the initial SOC. However, it is not limited thereto.

Hereinafter, an embodiment of controlling the ESS 20 by calculating the active power gain K _e according to the rotational speed ω _r of the rotor provided in the generator 10 according to the present disclosure will be described in detail.

9 is a flowchart illustrating an embodiment of controlling an ESS by calculating an active power gain according to the present disclosure.

Referring to FIG. 9, in step S911, the frequency difference value Δf is calculated by subtracting the rated frequency f _nom from the grid frequency f _sys , and in step S912, speed information included in the received generator information is obtained.

Then, in step S921, it is determined whether the frequency difference value Δf is greater than zero. If the frequency difference value Δf is not greater than zero, it is determined in step S922 whether the frequency difference value Δf is less than zero.

The frequency difference (Δf) is greater than zero, in step S931 by using the frequency difference (Δf) and the speed information to calculate the effective power gain (K _e). At this time, the active power gain (K _e ) is determined in proportion to the rotational speed (ω _r ) of the rotor provided in the generator (10). The reason is that, as described above, the generator 10 absorbs kinetic energy in the oversupply state, so that the rotational speed of the rotor (ω _r ) can reach the maximum value, thereby further increasing the absorption amount of the ESS 20 This is because the active power gain (K _e ) must be further increased.

Therefore, when the frequency difference (Δf) is greater than zero, ESS controller 220 may calculate the effective power gain (K _e), in proportion to the rotational speed (ω _r).

Then, in step S941 on the basis of the effective power gain (K _e) to control the water absorption of the ESS (20).

On the other hand, if the frequency difference value (Δf) is less than zero, in step S932, the active power gain (K _e ) is calculated using the frequency difference value (Δf) and the rotational speed (ω _r ) of the rotor, but the active power gain (K _e ) is determined in inverse proportion to the rotational speed of the rotor (ω _r ). The reason is that, as described above, the generator 10 discharges kinetic energy and outputs power in a situation where there is insufficient supply, so that the rotational speed of the rotor (ω _r ) can reach the minimum value, so the output amount of the ESS 20 This is because the active power gain (K _e ) must be further increased in order to further increase.

Therefore, when the frequency difference (Δf) is smaller than zero, ESS controller 220 may calculate the effective power gain (K _e), in inverse proportion to the rotational speed (ω _r).

Then, in step S942 on the basis of the effective power gain (K _e) to control the output amount of the ESS (20).

On the other hand, when the frequency difference value Δf is zero, the output of the ESS 20 may be maintained in step S943.

According to the foregoing, the ESS control device 200 according to the present disclosure performs cooperative control with the generator control device 100 and the ESS 20 according to the rotational speed ω _r of the rotor provided in the generator 10 It provides the effect of efficiently storing new and renewable energy or efficiently supplying electric energy by fluidly controlling the amount of output or absorption.

10 is a circuit diagram of an embodiment of an ESS control device 200 according to the present disclosure.

Referring to FIG. 10, the ESS control apparatus 200 according to the present disclosure may be implemented by designing a circuit for performing droop control. Here, the ESS control device 200 performing droop control receives the rated frequency (f _nom ) and the system frequency (f _sys ) and calculates a frequency difference value (Δf).

And, the ESS control device 200 calculates the gain (K _e ) of droop control using the frequency difference value (Δf) and the rotational speed (ω _r ) and SOC of the rotor received from the generator 10, and the frequency By multiplying the difference value (Δf) by the gain (K _e ) of the droop control, a reference value (P _ref ) of the active power for controlling the active power of the ESS (20) is calculated.

Then, the ESS control device 200 inputs a value obtained by subtracting the active power input from the power system (P _meas ) from the reference value (P _ref ) of the active power into a PI (Proportional-Integral) controller, and inputs the reference current (i _{q_ref} ) The power of the ESS 20 can be adjusted by calculating.

Meanwhile, as described above, the present disclosure can provide a cooperative control system for performing cooperative control between the generator control device 100 and the ESS control device 200.

Accordingly, modeling of the cooperative control system according to the present disclosure will be described later with reference to FIG. 11.

11 is a schematic diagram showing a model of a wind farm for simulating the present disclosure.

Referring to FIG. 10, the modeling shown in FIG. 10 uses a simulator to verify the performance of the generator control device 100 and the ESS control device 200 according to the present disclosure when the wind speed changes irregularly with time. It is composed of a mock system. The wind turbine 10 shown in FIG. 10 is modeled as a 2 MV permanent magnet synchronous generator (PMSG), and the ESS 20 is modeled as 500 kW. In addition, the diesel generator is modeled as 5 MV and the load is 6.5 MW.

12A to 12D are graphs showing execution results for the simulation according to FIG. 11.

Specifically, Figure 12a is a graph showing the grid frequency of the power system over time, Figure 12b is a graph showing the active power of the generator 10 according to the present disclosure over time, and Figure 12c is an ESS ( 20) is a graph showing the active power over time, and FIG. 12D is a graph showing the rotational speed of the rotor provided in the generator 10 according to the present disclosure over time.

According to the cooperative control system according to the present disclosure, it can be seen that the frequency deviation is 0.34 Hz, which is reduced by 0.04 Hz compared to when the conventional droop control is performed.

In addition, according to the cooperative control system according to the present disclosure, when the rotational speed of the rotor of the generator 10 is relatively small and the frequency deviation is less than 0, the active power gain (K _e ) of the ESS 20 increases, It can be seen that the frequency deviation decreases.

In addition, according to the cooperative control system according to the present disclosure, when the rotational speed of the rotor of the generator 10 is relatively large and the frequency deviation is greater than 0, the active power gain (K _e ) of the ESS 20 is relatively large. Has a value, and since the active power gain (K _w ) of the generator 10 has a relatively small value, it can be seen that the output of the generator 10 according to the present disclosure is larger than the conventional one.

In addition, according to the cooperative control system according to the present disclosure, it can be seen that the amount of new renewable energy, for example, wind energy introduced into the power system, stored as electric energy is further increased by about 360 kWh.

As described above, according to the present disclosure, the present disclosure is a cooperative control system capable of stably maintaining the grid frequency of the power system by performing cooperative control between the control device of the generator and the control device of the ESS, the generator control device and the ESS control. Device can be provided.

In addition, according to the present disclosure, the present disclosure is a cooperative control that enables stable operation of the generator by maintaining the rotational speed of the rotor included in the generator within the allowable range by performing cooperative control between the control device of the generator and the control device of the ESS. System, generator control device and ESS control device can be provided.

In addition, according to the present disclosure, the present disclosure provides cooperative control between the control device of the generator and the control device of the ESS, so that the contribution can be flexibly adjusted according to the state of each power source while continuously operating within the range that each power source can contribute. Cooperative control system, generator control device and ESS control device can be provided.

In addition, according to the present disclosure, a cooperative control system, a generator control device and an ESS control device are provided that minimize the loss of new and renewable energy and maximize the storage efficiency of ESS by performing cooperative control between the generator control device and the ESS control device. can do.

The description above and the accompanying drawings are merely illustrative of the technical idea of the present disclosure, and those of ordinary skill in the technical field to which the present disclosure pertains, combinations of configurations without departing from the essential characteristics of the present disclosure Various modifications and variations, such as separation, substitution, and alteration, will be possible. Accordingly, the embodiments disclosed in the present disclosure are not intended to limit the technical idea of the present disclosure, but to describe, and the scope of the technical idea of the present disclosure is not limited by these embodiments. That is, as long as it is within the scope of the problem solving of the present disclosure, one or more of the components may be selectively combined and operated. The scope of protection of the present disclosure should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present disclosure.

100: generator control device 110: generator communication unit
120: generator control unit 200: ESS control device
210: ESS communication unit 220: ESS control unit

Claims (16)

Generator communication unit for receiving ESS information from ESS (Energy Storage System); And
Generator that receives the rated frequency and system frequency of the power system and calculates a frequency difference value, calculates an active power gain based on the frequency difference value and the ESS information, and controls the output of the generator based on the active power gain Generator control device including a control unit. The method of claim 1,
The above ESS information is
Includes SOC information on the SOC (State OF Charge) of the ESS,
The generator control unit,
Generator control device, characterized in that adjusting the active power gain according to the SOC. The method of claim 2,
The generator control unit,
The value obtained by subtracting the rated frequency from the grid frequency is calculated as the frequency difference value,
When the frequency difference value is greater than zero, the generator control device, characterized in that calculating the active power gain in proportion to the SOC. The method of claim 2,
The generator control unit,
The value obtained by subtracting the rated frequency from the grid frequency is calculated as the frequency difference value,
When the frequency difference value is less than zero, the generator control device, characterized in that calculating the active power gain in inverse proportion to the SOC. The method of claim 1,
The generator control unit,
A generator control apparatus, characterized in that, while controlling the output of the generator by performing a droop control, the gain of the droop control is adjusted using the frequency difference value and the ESS information. The method of claim 1,
The generator control device, characterized in that receiving the rotational speed of the rotor provided in the generator, and calculating the active power gain based on the rotational speed. The method of claim 6,
The generator control unit,
A generator control device, characterized in that for calculating a driving supplement ratio using the rotation speed, a preset rated rotation speed, and a minimum value of the rotation speed, and calculating the active power gain by reflecting the driving supplement ratio. The method of claim 1,
The generator control unit,
When the frequency difference value is greater than zero, controlling the amount of absorption by which the generator absorbs power,
When the frequency difference value is less than zero, the generator control device, characterized in that for controlling the amount of output the generator outputs power. ESS communication unit for receiving generator information from the generator; And
ESS that receives the rated frequency and system frequency of the power system, calculates a frequency difference value, calculates an active power gain based on the frequency difference value and the generator information, and controls the output of the ESS based on the active power gain ESS control device including a control unit. The method of claim 9,
The generator information,
It includes speed information about the rotational speed of the rotor provided in the generator,
The ESS control unit,
ESS control device, characterized in that adjusting the active power gain according to the amount of change in the rotational speed. The method of claim 10,
The ESS control unit,
The value obtained by subtracting the rated frequency from the grid frequency is calculated as the frequency difference value,
When the frequency difference value is greater than zero, the ESS control device, characterized in that calculating the active power gain in proportion to the rotational speed. The method of claim 10,
The ESS control unit,
The value obtained by subtracting the rated frequency from the grid frequency is calculated as the frequency difference value,
When the frequency difference value is less than zero, the ESS control device, characterized in that calculating the active power gain in inverse proportion to the rotational speed. The method of claim 9,
The ESS control unit,
Controlling the output of the ESS by performing droop control, but adjusting the gain of the droop control using the frequency difference value and the generator information. The method of claim 9,
The ESS control unit,
ESS control apparatus, characterized in that receiving the SOC of the ESS and calculating the active power gain based on the SOC. The method of claim 9,
The ESS control unit,
When the frequency difference value is greater than zero, the ESS controls the amount of absorption to absorb power,
When the frequency difference value is less than zero, the ESS control device, characterized in that to control the amount of power output to the ESS. A generator control device for controlling an output of the generator based on a frequency difference value between the rated frequency of the power system and the grid frequency; And
Including an ESS control device for controlling the output of the ESS based on the frequency difference value,
The generator control device,
Receive SOC information about the SOC of the ESS, calculate a first active power gain based on the frequency difference value and the SOC information, and control an output amount or absorption amount of the generator based on the first active power gain ,
The ESS control device,
Receives speed information about the rotational speed of the rotor provided in the generator, calculates a second active power gain based on the frequency difference value and the speed information, and calculates a second active power gain based on the second active power gain. Cooperative control system, characterized in that controlling the amount of output or absorption.

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