WO2018236038A1 - Energy storage system - Google Patents

Abstract

The present invention relates to an energy storage system. An energy storage system according to an embodiment of the present invention is connected to a grid and a distributed power system, and comprises: a power condition system (PCS) for managing power of a distributed power system and power of a grid; a battery charged or discharged by the PCS; and an higher layer controller for generating a command value for controlling charging or discharging of the battery on the basis of a value of power generated by the distributed power system, and providing the generated command value to the PCS, wherein the higher layer controller comprises: a reference value calculation unit for calculating a reference value on the basis of a value of power generated by the distributed power system at a first time point and a value of power charged or discharged by the battery; an upper and lower limit value setting unit for setting an upper limit value and a lower limit value of a combined power target value of the distributed power system and the battery, on the basis of the calculated reference value; and a command value generation unit for generating a command value so that the combined power target value is larger than the lower limit value and is smaller than the upper limit value, on the basis of a power value of the distributed power system, which is measured at a second time point subsequent to the first time point.

Description

Energy storage system

The present invention relates to an energy storage system for stabilizing the output power of a distributed power system.

Energy Storage System is a system that stores generated power in each link system including power plant, substation and transmission line, and then uses energy selectively and efficiently at necessary time to enhance energy efficiency.

The energy storage system can reduce the power generation cost when the overall load ratio is improved by leveling the electric load with large time and seasonal variation, and it is possible to reduce the investment cost and the operation cost required for the electric power facility expansion, can do.

These energy storage systems are installed in power generation, transmission, distribution, and customer in power system. Frequency regulation, generator output stabilization using peak energy, peak shaving, load leveling, , And emergency power supply.

Energy storage systems are divided into physical energy storage and chemical energy storage depending on the storage method. Physical energy storage includes pumped storage, compressed air storage, and flywheel. Chemical storage includes lithium ion batteries, lead acid batteries, and Nas batteries.

On the other hand, there is a problem that it is difficult to predict the power flow due to the unstable output of a distributed power system, particularly a renewable energy system, which generates power in such an energy storage system.

Specifically, in the case of a wind power generation system among renewable energy systems, the output power amount may fluctuate depending on the amount of air that changes from time to time, and in the case of the solar power generation system, the output power amount may fluctuate due to the amount of clouds or the like.

The instability of the system is increasing due to the irregularly changing output of renewable energy system due to this weather change, and the collapse of the system can also be caused by the peak power generation amount of the large installed renewable energy system.

Accordingly, an energy storage system has recently emerged that minimizes the instability of the system and smoothes the output of the renewable energy system based on the charge / discharge of the battery, in order to deal with the generation amount exceeding the systematic limit value.

In this case, although the system can be stabilized by smoothing the output of the renewable energy system, a very large capacity battery is required for the smoothing operation, and the investment cost is rapidly increased. In addition, there is a problem that additional cost may be incurred considering the replacement cost due to battery life.

An object of the present invention is to provide an energy storage system capable of stabilizing the output power of a distributed power supply system by reducing the rate of change of output power (i.e., power supplied to the system) of the distributed power supply system through battery charging and discharging.

It is another object of the present invention to provide an energy storage system capable of stabilizing the output power of a distributed power supply system while reducing the capacity of a battery by reducing the rate of change of output power, not smoothing the output power of the distributed power supply system.

In order to achieve the above object, an energy storage system according to an embodiment of the present invention is an energy storage system connected to a grid and a distributed power supply system. The energy storage system includes a power condition system (PCS) And a host controller for generating a command value for controlling charging and discharging of the battery on the basis of the power value developed in the battery and the distributed power source system and providing the generated command value to the PCS, A reference value calculation unit for calculating a reference value based on a power value developed in the distributed power source system at a point in time and a power value charged and discharged by the battery and a reference value calculation unit for calculating an upper limit value and a lower limit value of the combined power target value of the distributed power source system and the battery based on the calculated reference value And a power value of the distributed power system measured at a second point in time after the first point of time As synthesizing power target value is greater than the lower limit value it includes an upper limit value than the reference value generating unit for generating a command value to a smaller value.

The command value generator generates a charge command value related to charging of the battery among the command values when the power value of the distributed power source system measured at the second time point is equal to or greater than the upper limit value and the power value of the distributed power source system measured at the second time point is And generates a discharge command value related to the discharge of the battery among the command values when it is equal to or lower than the lower limit value.

When the power value of the distributed power system measured at the second time point is equal to or greater than the upper limit value, the command value generating unit calculates a first result value, which is a difference between the power value and the upper limit value of the distributed power system measured at the second time point, A difference between the power value and the lower limit value of the distributed power supply system, and generates a charging command value such that the power value charged in the battery becomes a value between the first resultant value and the second resultant value.

If the power value of the distributed power system measured at the second point in time is equal to or less than the lower limit value, the command value generator calculates the command value at the second point in time based on the first result value, which is the difference between the power value and the upper limit value, And a discharge command value is generated such that a power value discharged from the battery is a value between a first resultant value and a second resultant value.

The PCS can control the SOC (State of Charge) of the battery within a preset stable range based on a command value provided from the host controller.

The host controller is a PMS (Power Management System) or an EMS (Energy Management System).

The reference value calculator updates the reference value every predetermined period, and the upper and lower limit value calculator updates the upper limit value and the lower limit value of the combined power target value based on the updated reference value every predetermined period.

According to another aspect of the present invention, there is provided an energy storage system connected to a grid and a distributed power supply system. The energy storage system includes a distributed power supply system and a power condition system (PCS) And a host controller for generating a command value for controlling charging and discharging of the battery on the basis of the power value developed in the battery and the distributed power source system and providing the generated command value to the PCS, A reference value calculation unit for calculating a reference value based on a power value developed in the distributed power source system at a point in time and a power value charged and discharged by the battery and a reference value calculation unit for calculating an upper limit value and a lower limit value of the combined power target value of the distributed power source system and the battery based on the calculated reference value And an upper limit value setting unit for setting the upper limit value setting unit and the lower limit value setting unit, Calculating a slope based on the power generation value of the stem, and the combined power target value is included between the upper and lower limit value of the command value generating section for generating a command value such that the power generation amount on the basis of the slope.

Wherein the command value generator calculates a predicted power value of the distributed power system at a third time point after the second time point based on the power generation slope when the power generation amount slope is an increasing slope and generates a command based on the calculated estimated power value of the distributed power system And calculates a predicted power value of the distributed power system at a third time point after the second time point based on the power generation amount slope when the power generation amount slope is a decrease slope, Based on the estimated power value of the system, a discharge command value associated with discharge of the battery among the command values is generated.

When the power value of the distributed power system measured at the second time point is equal to or greater than the upper limit value, the command value generator calculates a first result value which is a difference value between the power value and the upper limit value measured at the third time point, And generates a charging command value such that the electric power value to be charged is equal to or greater than the first resultant value.

If the power value of the distributed power system measured at the second time point is equal to or less than the lower limit value, the command value generator calculates a second result value, which is a difference value between the power value and the lower limit value measured at the third time point, And generates a discharge command value such that the discharged electric power value is equal to or greater than the second resultant value.

The time difference between the first time and the second time is a first time, the time difference between the second time and the third time is N times the first time, and N is a natural number of 2 or more.

According to another aspect of the present invention, there is provided an energy storage system connected to a grid and a distributed power supply system. The energy storage system includes a distributed power supply system and a power condition system (PCS) And a host controller for generating a final command value for controlling charging and discharging of the battery on the basis of the battery power charged and discharged by the PCS and the power value developed in the distributed power source system and providing the generated final command value to the PCS, A reference value calculation unit for calculating a reference value based on a power value generated in the distributed power system at the first time point and a power value charged and discharged by the battery, and a reference value calculation unit for calculating an upper limit value And a lower limit value setting unit for setting a lower limit value, A command value generator for generating an initial command value so that the combined power target value becomes a lower limit value or an upper limit value based on the power value of the system; and a command value generator for correcting the initial command value so that the combined power target value is larger than the lower limit value and smaller than the upper limit value, And a command value correcting section for generating a command value.

The command value generating unit generates an initial charge command value related to charging of the battery among the initial command values when the power value of the distributed power source system measured at the second time point is equal to or greater than the upper limit value, The initial discharge command value related to the discharge of the battery among the initial command values is generated.

Wherein the command value generator calculates a first result value that is a difference between a power value and an upper limit value of the distributed power system measured at the second time point when the power value of the distributed power source system measured at the second time point is equal to or greater than the upper limit value, And generates an initial charge command value based on the resultant value.

The command value correcting unit generates a final charge command value related to charging of the battery among the final command values based on the initial charge command value supplied from the command value generator so that the power value charged by the battery is greater than the first result value .

The command value generator calculates a second result value that is a difference value between the power value and the lower limit value of the distributed power system measured at the second time point when the power value of the distributed power source system measured at the second time point is less than the lower limit value, And generates an initial discharge command value based on the resultant value.

The command value correcting unit generates a final discharge command value related to the discharge of the battery among the final command values so that the power value discharged from the battery is greater than the second result value based on the initial discharge command value supplied from the command value generator .

As described above, according to the present invention, the output power of the distributed power supply system can be stabilized by reducing the rate of change of the output power (that is, the power supplied to the system) of the distributed power system through the battery charge / discharge, The instability can be reduced. In addition, the output power of the distributed power supply system is stabilized by reducing the rate of change of the output power, not the smoothing of the output power of the distributed power supply system, so that the capacity of the battery can be reduced. Also, by reducing the capacity of the battery, the battery cost can be reduced.

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

1 is a view illustrating an energy storage system according to an embodiment of the present invention.

2 is a view for explaining the PMS of FIG.

3 and 4 are graphs illustrating the process of stabilizing the output power of the distributed power system.

5 is a graph illustrating an example of a method by which the energy storage system of Fig. 1 stabilizes the output power of a distributed power system.

Figures 6 and 7 are graphs illustrating another example of a method by which the energy storage system of Figure 1 stabilizes the output power of a distributed power system.

Figs. 8 and 9 are graphs illustrating another example of a method by which the energy storage system of Fig. 1 stabilizes the output power of a distributed power system. Fig.

10 is a graph illustrating another example of a method by which the energy storage system of FIG. 1 stabilizes the output power of a distributed power system; FIG.

The above and other objects, features, and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, which are not intended to limit the scope of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to denote the same or similar elements.

Hereinafter, an energy storage system 1 according to an embodiment of the present invention will be described with reference to Figs. 1 to 4. Fig.

1 is a view illustrating an energy storage system according to an embodiment of the present invention. 2 is a view for explaining the PMS of FIG. 3 and 4 are graphs illustrating the process of stabilizing the output power of the distributed power system.

1, an energy storage system 1 according to an embodiment of the present invention includes a PCS 100, a battery 110, a BMS 120, a PMS 130, Management System), and an EMS 140 (Energy Management System).

The PCS 100 can manage the power of the grid (GRID) and the distributed power system (DG).

Specifically, the PCS 100 can store the power generated in the distributed power system DG in the battery 110 or transfer it to the grid (GRID) and the load (L). Also, the PCS 100 may transmit the power stored in the battery 110 to the grid (GRID) or the load (L). The PCS 100 may store the power supplied from the grid (GRID) in the battery 110. [

The PCS 100 can also control the charging / discharging (i.e., charging or discharging) of the battery 110 based on the state of charge (hereinafter referred to as " SOC level ") of the battery 110 .

In addition, the PCS 100 can control the charging / discharging of the battery 110 based on the command value supplied from the PMS 130.

For reference, the PCS 100 generates a schedule for the operation of the energy storage system 2 based on the power price of the power market, the power generation demand of the distributed power system (DG), the power generation amount and the grid (GRID) can do.

The battery 110 may be charged and discharged by the PCS 100. [

Specifically, the battery 110 may receive and store at least one of the power of the distributed power system DG and the grid GRID, and may supply the stored power to at least one of the grid (GRID) and the load L . The battery 110 may include at least one battery cell, and each battery cell may include a plurality of bare cells.

For reference, a distributed power system (DG) is a system that is connected to a grid (GRID) and produces power using an energy source.

These distributed power systems (DGs) can produce electricity using one or more of fossil fuels, nuclear fuels, and renewable energy. For example, a distributed power system (DG) can be a renewable power generation system using renewable energy such as solar power generation system, wind power generation system, and tidal power generation system.

Also, the grid (GRID) may include power plants, substations, transmission lines, and the like. This grid GRID may supply power to one or more of the energy storage system 1, the load L and the distributed power supply system DG and may be connected to one or more of the distributed power system DG and the energy storage system 1 Power may be supplied from the power source.

Further, the load L is supplied with power from at least one of the distributed power system DG, the battery 110, and the grid GRID, and consumes the supplied power.

For example, the load L may include a home, a large building, a factory, and the like.

The BMS 120 can monitor the state of the battery 110 and control the charging and discharging operations of the battery 110. [ The BMS 120 may also monitor the state of the battery 110 including the SOC level of the battery 110 in a charged state and may monitor the state of the monitored battery 110 (e.g., voltage, current, Power consumption, life span, charge state, etc.) information to the PCS 100.

In addition, the BMS 120 may perform a protection operation for protecting the battery 110. For example, the BMS 120 may perform at least one of an overcharge protection function, an over discharge protection function, an over current protection function, an over voltage protection function, an overheat protection function, and a cell balancing function for the battery 110.

In addition, the BMS 120 may adjust the SOC level of the battery 110.

Specifically, the BMS 120 receives the control signal from the PCS 100 and can adjust the SOC level of the battery 110 based on the received signal.

The PMS 130 may control the PCS 100 based on data associated with the battery 110 provided by the BMS 120. [

In particular, the PMS 130 may monitor the status of the battery 110 and monitor the status of the PCS 100. In other words, the PMS 130 can control the PCS 100 according to the efficiency based on the data related to the battery 110 received from the BMS 120.

The PMS 130 may also monitor the status of the battery 110 through the BMS 120 and provide the collected data to the EMS 140.

2 to 4, the PMS 130 may be an upper controller, and the host controller 130 controls the charging / discharging of the battery 110 based on the power value developed in the distributed power system DG And provide the generated command value to the PCS 100. The command value may be provided to the PCS 100. [

Specifically, the PMS 130 may include a reference value calculation unit 132, an upper / lower limit value setting unit 134, and a command value generation unit 136.

Based on the power value developed in the distributed power system DG and the power value charged and discharged by the battery 110 at a specific time point (for example, the first time point (11:59)), the reference value calculation unit 132 calculates a reference value Can be calculated.

That is, the reference value calculation unit 132 receives the generated power values and the charged and discharged power values at a specific point in time from the distributed power system DG and the battery 110, respectively, and calculates a reference value based on the generated power value and the charged / The combined power value can be calculated.

For reference, the composite power value may be a reference value.

That is, as shown in FIG. 3 and FIG. 4, it can be seen that the power developed in the distributed power system (i.e., the generated power of the distributed power system) is abruptly changed. On the other hand, it can be seen that the composite output (i.e., the composite power) to which the charge and discharge of the battery is applied to the electric power developed in the distributed power supply system is relatively suppressed abruptly.

The synthesized power values (e.g., MV1 and MV2) calculated for each period can be calculated based on the combined power (for example, As shown in FIG.

On the other hand, the upper and lower limit value setting unit 134 can set the upper limit value TARGETMAX and the lower limit value TARGETMIN of the combined power target value of the distributed power supply system DG and the battery 110 based on the calculated reference value.

Here, the combined power target value of the distributed power system DG and the battery 110 means a target value of the output power expected when the charge and discharge of the battery 110 is applied to the power generated in the distributed power system DG can do.

Specifically, the upper and lower limit value setting unit 134 can receive the reference value from the reference value calculating unit 132 and set the upper limit value TARGET MAX and the lower limit value TARGET MIN of the combined power target value on the basis of the supplied reference value .

For reference, since the reference value is calculated every predetermined period, the upper limit value TARGETMAX and the lower limit value TARGETMIN of the combined power target value can also be newly set every predetermined period.

For example, the upper limit value TARGET MAX may be a value obtained by adding a% (for example, a is a positive number) of the maximum output value (i.e., peak value) of the distributed power supply system DG to a reference value calculated every predetermined period .

The lower limit value TARGET MIN may be a value obtained by subtracting a% (for example, a is a positive number) of the maximum output value (i.e., the peak value) of the distributed power supply system DG from a reference value calculated every predetermined period.

Accordingly, when the maximum output value of the distributed power system DG is 25 MW and the reference value is XKW (for example, X is an integer) and a is 1, the upper limit value TARGET MAX may be XKW + 250 KW, (TARGET MIN) may be XKW-250KW.

Based on the power value of the distributed power system (DG) measured at a second time point after the first time point (for example, any time point between 11:59 and 12:00), the command value generation unit 136 generates a command value The command value can be generated such that the power target value is included in the variation limit range (lower limit value to upper limit value).

For example, the command value may include a charge command value associated with charging of the battery 110 and a discharge command value associated with discharge of the battery 110. [

Further, the command value generator 136 can provide the generated command value to the PCS (100 in Fig. 1).

The PCS (100 in FIG. 1) can control the charge / discharge of the battery (110 in FIG. 1) based on the command value supplied from the command value generator 136 so that the combined power does not deviate from the variation limit range.

For reference, the PMS 130 may further include a command value correcting unit (not shown) according to the output stabilization method of the distributed power system DG. A detailed description thereof will be given later.

1, the EMS 140 generates information on the maintenance and repair of the battery 110 based on data on the battery 110 provided from the PMS 130, To the BMS 120 via the PMS 130. [0050]

For reference, the EMS 140, not the PMS 130, may perform the above-described command value generation function as an upper controller. However, for convenience of explanation, the present invention will be described by taking as an example a case where the PMS 130 is a host controller.

The switch SW may be disposed between the grid GRID and the PCS 100 and may be opened when a power failure of the grid GRID is detected and may be closed when the power grid GRID is detected .

Hereinafter, an example of a method of stabilizing the output power of the distributed power supply system of the energy storage system of FIG. 1 will be described with reference to FIG.

5 is a graph illustrating an example of a method by which the energy storage system of Fig. 1 stabilizes the output power of a distributed power system.

2 and 5, in order to stabilize the output power of the distributed power system DG, first, the reference value calculator 132 calculates the power value developed at the distributed power system DG at the first time point P1, The reference value MV1 can be calculated on the basis of the power value charged / discharged by the power supply (110 in Fig. 1).

Here, the reference values MV1 and MV2 may be updated every predetermined period (for example, intervals between P1 and P6, i.e., one minute).

When the reference value MV1 is calculated, the upper / lower limit value setting unit 134 sets the upper limit value TARGET MAX1 of the combined power target value of the distributed power supply system DG and the battery (110 in Fig. 1) The lower limit value (TARGET MIN1) can be set.

Here, the upper limit value of the combined power target value may be a value obtained by adding a% (for example, a is a positive number) of the maximum output value of the distributed power system DG to a reference value updated every predetermined period.

Further, the lower limit value of the combined power target value may be a value obtained by subtracting a% (for example, a is a positive number) of the maximum output value of the distributed power system DG from a reference value updated every predetermined period.

That is, the upper limit value and the lower limit value of the combined power target value can be updated based on the updated reference value every predetermined period.

When the upper limit value TARGET MAX1 and the lower limit value TARGET MIN1 of the combined power target value are set, the command value generator 136 generates a command value at the next time point after the first time point P1 (for example, at the second time point P2) The command value can be generated such that the combined power target value is the lower limit value TARGET MIN1 or the upper limit value TARGET MAX1, based on the power value of the distributed power supply system DG measured in the power control mode.

Specifically, as shown in FIG. 5, the command value generator 136 generates a command value (e.g., a command value) from the battery (110 in FIG. 1) when the power value of the distributed power system DG measured at a specific point in time exceeds the upper limit value TARGET MAX1. And generates a discharge command value associated with the discharge of the battery (110 in FIG. 1) when the power value of the distributed power system DG measured at a specific point in time is less than the lower limit value TARGET MIN1 .

That is, when the power value of the distributed power system DG measured at a specific point in time exceeds the upper limit value TARGET MAX1, the command value generator 136 calculates the command value of the power value of the distributed power system DG A first result value that is a difference value of the upper limit value TARGET MAX1 may be calculated and a charge command value may be generated such that the power value charged to the battery 110 (FIG. 1) becomes the first resultant value.

On the other hand, when the power value of the distributed power system DG measured at a specific point in time is less than the lower limit value TARGET MIN1, the command value generator 136 outputs the power value of the distributed power system DG measured at the specific point in time and the lower limit value (TARGET MIN1), and generate a discharge command value such that the power value discharged from the battery (110 in FIG. 1) becomes the second resultant value.

The command value generation unit 136 may provide the PCS 100 with a charging command value or a discharge command value generated through the above process and the PCS 100 may generate the charging command value or the discharge command value based on the supplied charging command value or the discharge command value The battery (110 in Fig. 1) can be charged and discharged.

5, when the power value of the distributed power system DG is measured to be less than the lower limit value TARGET MIN1 at the second time point P2, the command value generator 136 generates the command value A second result which is the difference between the power value of the distributed power system DG measured at the time point P2 and the lower limit value TARGET MIN1 is calculated and the power value discharged from the battery 110 The discharge command value DC1 can be generated.

The command value generating unit 136 may provide the generated discharge command value DC1 to the PCS 100 and the PCS 100 may supply the battery 110 of FIG. 1 on the basis of the provided discharge command value DC1 The composite power value can be made to be the lower limit value by discharging. In addition, through this, the combined power can be included within the variation limit range (lower limit value to upper limit value).

The discharge mechanism may be performed at the third time point P3 and the second time point P2.

5, when the power value of the distributed power system DG is measured to exceed the upper limit value TARGET MAX1 at the fourth point in time P4, the command value generator 136 generates A first result value which is a difference value between the power value of the distributed power supply system DG measured at the fourth time point P4 and the upper limit value TARGET MAX1 is calculated and the power value charged to the battery 110 It is possible to generate the charging command value CC1 so as to be the resultant value.

The command value generating unit 136 may provide the generated charging command value CC1 to the PCS 100 and the PCS 100 may supply the battery 110 of FIG. 1 on the basis of the supplied charging command value CC1 So that the combined power value can be made the upper limit value. In addition, through this, the combined power can be included within the variation limit range (lower limit value to upper limit value).

Such a charging mechanism may be performed through the same process as the fourth time point P4 at the fifth time point P5.

For reference, the output power stabilization process of the above-described distributed power supply system may be performed after the sixth time point P6 through the same mechanism.

Hereinafter, with reference to FIG. 6 and FIG. 7, another example of a method of stabilizing the output power of the distributed power supply system of the energy storage system of FIG. 1 will be described.

Figures 6 and 7 are graphs illustrating another example of a method by which the energy storage system of Figure 1 stabilizes the output power of a distributed power system.

The operation principle of the reference value calculation unit 132 and the upper / lower limit value setting unit 134 is the same as that of FIG. 5, and a description thereof will be omitted.

2, 6 and 7, when the upper limit value TARGETMAX and the lower limit value TARGETMIN of the reference value MV1 and the synthesized power target value are set, the command value generator 136 generates a command value The combined power target value is larger than the lower limit value TARGETMIN and the upper limit value TARGETMAX based on the power value of the distributed power system DG measured at the next time point A command value can be generated so as to be a small value.

Specifically, as shown in FIGS. 6 and 7, the command value generating unit 136 generates a command value when the power value of the distributed power system DG measured at a specific point in time (for example, the third point of time P3) When the power value of the distributed power system DG measured at the third time point P3 is equal to or lower than the lower limit value TARGET MIN, the charge command value associated with the charge of the battery (110 in FIG. 1) It is possible to generate a discharge command value associated with discharge of the battery (110 in Fig. 1).

That is, when the power value of the distributed power system DG measured at the third time point P3 is equal to or greater than the upper limit value TARGETMAX, the command value generating unit 136 generates the command value DG and the difference between the power value of the distributed power system DG measured at the third point of time P3 and the lower limit value TARGET MIN, which is the difference between the power value of the distributed power system DG and the upper limit value TARGET MAX, And generate a charging command value so that the power value charged to the battery (110 in Fig. 1) becomes a value between the first resultant value and the second resultant value.

On the other hand, when the power value of the distributed power system DG measured at the third time point P3 is equal to or less than the lower limit value TARGET MIN, the command value generation unit 136 generates a command value, Which is a difference between the power value of the distributed power system DG and the lower limit value TARGETMIN measured at the third time point P3 and the first resultant value which is the difference between the power value of the distributed power system DG and the upper limit value TARGETMAX, 2, and generate a discharge command value such that the power value discharged from the battery (110 in FIG. 1) becomes a value between the first resultant value and the second resultant value.

The command value generation unit 136 may provide the PCS 100 with a charging command value or a discharge command value generated through the above process and the PCS 100 may generate the charging command value or the discharge command value based on the supplied charging command value or the discharge command value The battery (110 in Fig. 1) can be charged and discharged.

6, when the power value of the distributed power system DG is measured to be equal to or lower than the lower limit value TARGETMIN at the third time point P3, the command value generator 136 generates the third The first result which is the difference between the power value of the distributed power system DG measured at the time point P3 and the upper limit value TARGETMAX and the power value of the distributed power system DG measured at the third time point P3 And a second resultant value which is a difference value of the lower limit value TARGETMIN is calculated and the discharge command value DC2 (DC2) is calculated so that the power value discharged from the battery (110 in FIG. 1) becomes a value between the first resultant value and the second resultant value Can be generated.

The command value generating unit 136 may provide the generated discharge command value DC2 to the PCS 100 and the PCS 100 may supply the battery 110 of FIG. 1 on the basis of the provided discharge command value DC2 By discharging, the combined power value can be made larger than the lower limit value (TARGET MIN) and smaller than the upper limit value (TARGET MAX).

In this way, the combined power can be included within the range of variation limits (lower limit to upper limit).

In addition, when the SOC of the battery (110 in FIG. 1) has a too high value depending on the weather conditions, the battery (110 in FIG. 1) is further discharged by increasing the combined power value to be larger than the lower limit value (TARGET MIN) 1 < SEP > 110 < SEP > 1 < SEP >

Thereby, it is possible to control not only the synthesized power but also the SOC of the battery (110 in FIG. 1) to be within a stable numerical value range at the same time.

The discharge command values DC1 and DC3 generated at the second time point P2 and the fourth time point P4 are set such that the combined power target value is the upper limit value TARGET MAX or the lower limit value TARGET MIN, Is different from the discharge command value DC1 generated at the third time point P3.

That is, the discharge amount of the battery (110 in FIG. 1) by the discharge command value DC2 generated at the third time point P3 is equal to the discharge command value DC2 generated by the discharge command value DC1 generated at the second time point P2 1) of the battery (110 in Fig. 1) by the discharge command value DC3 generated at the fourth time point P4.

7, when the power value of the distributed power system DG is measured to be equal to or higher than the upper limit value TARGET MAX at the third time point P3, the command value generation unit 136 generates the command value The first result which is the difference between the power value of the distributed power system DG and the upper limit value TARGET MAX measured at the third point P3 and the power value of the distributed power system DG measured at the third point of time P3, (TARGET MIN), and calculates a second resultant value as a difference between the charge command value CC2 so that the power value charged to the battery (110 in FIG. 1) becomes a value between the first resultant value and the second resultant value, Can be generated.

The command value generating unit 136 may provide the generated charging command value CC2 to the PCS 100 and the PCS 100 may supply the battery 110 of FIG. 1 on the basis of the supplied charging command value CC2 The composite power value can be made smaller than the upper limit value by charging.

In this way, the combined power can be included within the range of variation limits (lower limit to upper limit).

1) 110 by further charging the battery (110 in FIG. 1) so that the combined power value is smaller than the upper limit value when the SOC of the battery (110 in FIG. 1) May be arbitrarily increased so as to allow the SOC of the engine to fall within a preset stable range.

Thereby, it is possible to control not only the synthesized power but also the SOC of the battery (110 in FIG. 1) to be within a stable numerical value range at the same time.

The charging command values CC1 and CC3 generated at the second time point P2 and the fourth time point P4 are set such that the combined power target value is the upper limit value TARGET MAX or the lower limit value TARGET MIN, Is different from the charging command value CC1 generated at the third time point P3.

That is, the amount of charge of the battery (110 in FIG. 1) by the charge command value CC2 generated at the third time point P3 is smaller than the charge amount of the battery (FIG. 1) by the charge command value CC1 generated at the second time point P2 (110 in FIG. 1) by the charging command value CC3 generated at the fourth time point P4 and the charging amount of the battery (110 in FIG.

Hereinafter, with reference to FIG. 8 and FIG. 9, another example of a method of stabilizing the output power of the distributed power supply system of the energy storage system of FIG. 1 will be described.

Figs. 8 and 9 are graphs illustrating another example of a method by which the energy storage system of Fig. 1 stabilizes the output power of a distributed power system. Fig.

The operation principle of the reference value calculation unit 132 and the upper / lower limit value setting unit 134 is the same as that of FIG. 5, and a description thereof will be omitted.

2, 8 and 9, when the upper limit value TARGETMAX and the lower limit value TARGETMIN of the reference value MV1 and the synthesized power target value are set, the command value generator 136 generates the command value MV2 at the second time point P2 And the power value of the distributed power system DG measured at the third point of time P3 after the second point of time P 2 and calculates the power generation slope Slope based on the power generation slope Slope, The command value can be generated so that the value is a value between the upper limit value TARGET MAX and the lower limit value TARGET MIN.

Specifically, as shown in FIGS. 8 and 9, the command value generator 136 generates a command value from the second time point P3 on the basis of the power generation amount slope when the power generation amount slope is an increasing slope, The estimated power value of the distributed power system DG at the fifth point in time P5 can be calculated. Also, the command value generator 136 may generate a charging command value related to charging of the battery (110 in Fig. 1) based on the calculated estimated power value of the distributed power system DG.

The command value generating unit 136 generates a command value based on the power generation slope Slope when the power generation amount slope is a decreasing slope, It is possible to calculate the estimated power value of the power supply DG. Also, the command value generator 136 may generate a discharge command value related to the discharge of the battery (110 in FIG. 1) based on the calculated estimated power value of the distributed power system DG.

That is, when the output power of the distributed power system DG continuously increases to be higher than the upper limit value TARGET MAX (that is, in the case of the increasing slope), the battery 110), the combined power may still remain at a value greater than the upper limit value TARGET MAX.

Further, when the output power of the distributed power system DG continuously decreases to be lower than the lower limit value TARGET MIN (i.e., in the case of the decreasing slope), the battery 110), the combined power may still remain below the lower limit (TARGET MIN).

Therefore, when the power value of the distributed power system DG measured at the third time point P3 is equal to or greater than the upper limit value TARGETMAX, the command value generation unit 136 generates the command value DG) and a difference value between the upper limit value TARGETMAX and a charge command value so that the power value charged to the battery 110 (FIG. 1) becomes the first resultant value .

On the other hand, when the power value of the distributed power system DG measured at the third time point P3 is equal to or less than the lower limit value TARGET MIN, the command value generating unit 136 generates a command value, A second result value which is a difference value between the power value of the battery DG and the lower limit value TARGET MIN can be calculated and a discharge command value can be generated so that the power value discharged from the battery 110 have.

The command value generation unit 136 may provide the PCS 100 with a charging command value or a discharge command value generated through the above process and the PCS 100 may generate the charging command value or the discharge command value based on the supplied charging command value or the discharge command value The battery (110 in Fig. 1) can be charged and discharged.

For example, if it is determined that the power value of the distributed power system DG is continuously increased at the second point of time P2 and the third point of time P3 as shown in FIG. 8, the command value generator 136 calculates the difference between the power value of the distributed power system DG and the upper limit value TARGET MAX measured at the fifth point of time P5 that is two points later than the third point of time P3 based on the calculated power generation slope Slope And generates a charging command value CC2 so that the power value charged to the battery (110 in FIG. 1) becomes the second resultant value.

The time difference between the second time point P2 and the third time point P3 is the first time and the time difference between the third time point P3 and the fifth time point P5 is N times N May be a natural number of 2 or more).

Of course, N may be a positive number greater than 1 but not a natural number of 2 or more, or may be a distributed power system measured at a particular time after one or more than three time points, rather than after two time points after the third time point P3. The estimated power value of the current power DG may be used. However, in the present invention, for convenience of explanation, N is a natural number of 2 or more, and is measured at a fifth point of time P5 after two points of time from the third point of time P3 The estimated power value of the distributed power supply system DG will be described as an example.

The command value generating unit 136 may provide the generated charging command value CC2 to the PCS 100 and the PCS 100 may supply the battery 110 of FIG. 1 on the basis of the supplied charging command value CC2 So that the combined power value can be a value between the upper limit value TARGET MAX and the lower limit value TARGET MIN.

In this way, the combined power can be included within the range of variation limits (lower limit to upper limit).

8, the charge amount of the battery (110 in FIG. 1) by the charge command value CC2 generated at the fifth time point P5 is equal to the charge command value generated at the third time point P3 (110 in FIG. 1) by the battery cell CC1.

9, when it is measured that the power value of the distributed power system DG is continuously decreased at the second point of time P2 and the third point of time P3, the command value generator 136 Is a difference value between the power value of the distributed power system DG and the lower limit value TARGET MIN measured at the fifth point of time P5 which is two points after the third point of time P3 based on the calculated power generation slope Slope , And generate a discharge command value DC2 such that the power value discharged from the battery (110 in FIG. 1) becomes the second resultant value.

The time difference between the second time point P2 and the third time point P3 is the first time and the time difference between the third time point P3 and the fifth time point P5 is N times N May be a natural number of 2 or more).

The command value generating unit 136 may provide the generated discharge command value DC2 to the PCS 100 and the PCS 100 may supply the battery 110 of FIG. 1 on the basis of the provided discharge command value DC2 By discharging, the combined power value can be a value between the upper limit value TARGET MAX and the lower limit value TARGET MIN.

In this way, the combined power can be included within the range of variation limits (lower limit to upper limit).

9, the discharge amount of the battery (110 in FIG. 1) by the discharge command value DC2 generated at the fifth time point P5 is equal to the discharge command value D3 generated at the third time point P3, (110 in Fig. 1) by the value DC1.

Hereinafter, with reference to FIG. 10, another example of a method of stabilizing the output power of the distributed power supply system of the energy storage system of FIG. 1 will be described.

10 is a graph illustrating another example of a method by which the energy storage system of FIG. 1 stabilizes the output power of a distributed power system; FIG.

The operation principle of the reference value calculation unit 132 and the upper / lower limit value setting unit 134 is the same as that of FIG. 5, and a description thereof will be omitted.

2 and 10, when the upper limit value TARGET MAX1 and the lower limit value TARGET MIN1 of the reference value MV1 and the synthesized power target value are set, the command value generation unit 136 generates a command value The initial command value (TARGET) is set such that the combined power target value is the lower limit value TARGET MIN1 or the upper limit value TARGET MAX1, based on the power value of the distributed power system DG measured at the next time point (for example, (Initial charge command value or initial discharge command value).

10, when the power value of the distributed power system DG measured at a specific point in time is equal to or greater than the upper limit value TARGET MAX1, the command value generator 136 determines that the battery (110 of FIG. 1) And generates an initial discharge command value related to the discharge of the battery (110 in FIG. 1) when the power value of the distributed power system DG measured at a specific point in time is lower than the lower limit value TARGET MIN1 .

That is, when the power value of the distributed power system DG measured at a specific point in time is equal to or greater than the upper limit value TARGET MAX1, the command value generator 136 outputs the power value of the distributed power system DG measured at the specific point in time and the upper limit value TARGET MAX1), and generate an initial charge command value such that a power value charged to the battery (110 in FIG. 1) becomes a first resultant value.

On the other hand, when the power value of the distributed power system DG measured at a specific point in time is equal to or less than the lower limit value TARGET MIN1, the command value generator 136 outputs the power value of the distributed power system DG measured at the specific point in time, (TARGET MIN1), and generate the initial discharge command value so that the power value discharged from the battery (110 in FIG. 1) becomes the second resultant value.

The command value generating unit 136 may provide the command value correcting unit (not shown) with the initial charge command value or the initial charge command value generated through the process described above.

The command value correcting unit can generate the final command value (final charge command value or final discharge command value) by correcting the initial command value such that the combined power target value is larger than the lower limit value (TARGET MIN1) and smaller than the upper limit value (TARGET MAX1) have.

Specifically, the command value correcting unit receives the initial command value from the command value generating unit 136, corrects the provided initial command value, and outputs a command value larger than the lower limit value TARGET MIN1 and smaller than the upper limit value TARGET MAX1 The final command value can be generated.

For reference, the command value correcting unit may be included in the command value generating unit 136 or may exist separately.

10, when the power value of the distributed power system DG is measured to be equal to or lower than the lower limit value TARGET MIN1 at the second time point P2, the command value generator 136 generates the command value A second result which is the difference between the power value of the distributed power system DG measured at the time point P2 and the lower limit value TARGET MIN1 is calculated and the power value discharged from the battery 110 The initial discharge command value DC1 can be generated.

The command value generating unit 136 may provide the generated initial discharge command value DC1 to the command value correcting unit. The command value correcting unit may calculate the command value DC1 based on the provided initial discharge command value DC1, The final discharge command value DC1 'may be generated such that the power value discharged from the first discharge command value is greater than the second result value.

Also, the command value generator 136 may provide the generated final discharge command value DC1 'to the PCS 100, and the PCS 100 may calculate the final discharge command value DC1' based on the received final discharge command value DC1 ' 1 of 110) is discharged, the combined power value can be made larger than the lower limit value TARGET MIN1.

In addition, through this, the combined power can be included within the variation limit range (lower limit value to upper limit value).

On the other hand, when discharging the battery (110 in FIG. 1) in accordance with the lower limit value TARGET MIN1, the combined electric power can be measured to be out of the variation limit range due to the error in the combined electric power measurement. Therefore, by discharging the battery (110 in FIG. 1) such that the combined power value is larger than the lower limit value TARGET MIN1, it is possible to prevent a possibility that the combined power is erroneously measured as being out of the fluctuation limit range.

The discharge mechanism may be performed at the third time point P3 and the second time point P2.

10, when the power value of the distributed power system DG is measured to be equal to or higher than the upper limit value TARGET MAX1 at the fourth time point P4, the command value generator 136 generates the command value A first result value which is a difference value between the power value of the distributed power system DG measured in step P4 and the upper limit value TARGET MAX1 is calculated and the power value charged to the battery 110 The initial charging command value CC1 can be generated.

The command value generating unit 136 may supply the generated initial charge command value CC1 to the command value correcting unit and the command value correcting unit may be configured to generate the command value CC1 based on the provided initial charge command value CC1, The final charging command value CC1 'may be generated so that the power value to be charged to the first charging current value is greater than the first charging current value.

The command value generator 136 may also provide the generated final charge command value CC1 'to the PCS 100 and the PCS 100 may calculate the final charge command value CC1' based on the received final charge command value CC1 ' 1) 110 of the first and second embodiments, the combined power value can be a value smaller than the upper limit value TARGET MAX1.

In addition, through this, the combined power can be included within the variation limit range (lower limit value to upper limit value).

On the other hand, when the battery (110 of FIG. 1) is charged in accordance with the upper limit value TARGET MAX1, it can be measured that the combined power deviates from the variation limit range due to the error in the combined power measurement. Therefore, by charging the battery (110 in FIG. 1) so that the combined power value is smaller than the upper limit value TARGET MAX1, it is possible to prevent the possibility that the combined power is erroneously measured as being out of the fluctuation limit range.

This discharge mechanism may be performed through the same process as the fourth time point P4 at the fifth time point P5.

As described above, according to the present invention, by reducing the rate of change of the output power of the distributed power system DG (that is, the power supplied to the grid GRID) through the charging and discharging of the battery 110, The output power of the grid GRID can be stabilized and the instability of the grid GRID can be reduced. Also, the output power of the distributed power system DG is stabilized by reducing the rate of change of the output power, not the smoothing of the output power of the distributed power system DG, thereby reducing the capacity of the battery 110. Also, by reducing the capacity of the battery 110, the battery cost can be reduced.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, But the present invention is not limited thereto.

Claims (18)

An energy storage system coupled to a grid and a distributed power system, A PCS (Power Condition System) for managing power of the distributed power system and the system; A battery charged and discharged by the PCS; And And an upper controller for generating a command value for controlling charge / discharge of the battery based on the power value developed in the distributed power supply system and providing the generated command value to the PCS, Wherein the host controller comprises: A reference value calculation unit for calculating a reference value based on a power value developed in the distributed power system at a first time point and a power value charged / An upper and lower limit value setting unit for setting an upper limit value and a lower limit value of the combined power target value of the distributed power system and the battery based on the calculated reference value, And a command value generator for generating the command value such that the combined power target value is larger than the lower limit value and smaller than the upper limit value based on the power value of the distributed power system measured at the second time point after the first time point doing Energy storage system. The method according to claim 1, Wherein the command value generating unit comprises: Generates a charging command value related to the charging of the battery among the command values when the power value of the distributed power system measured at the second time point is not less than the upper limit value, And generates a discharge command value related to the discharge of the battery among the command values when the power value of the distributed power system measured at the second time point is not more than the lower limit value Energy storage system. 3. The method of claim 2, Wherein the command value generator generates the command value when the power value of the distributed power system measured at the second time point is equal to or greater than the upper limit value, A first result which is a difference between a power value of the distributed power system measured at the second time point and the upper limit value and a second result which is a difference between a power value of the distributed power system measured at the second time point and the lower limit; ≪ / RTI > And generates the charging command value so that a power value charged to the battery becomes a value between the first resultant value and the second resultant value Energy storage system. 3. The method of claim 2, Wherein the command value generator generates the command value when the power value of the distributed power system measured at the second time point is less than the lower limit value, A first result which is a difference between a power value of the distributed power system measured at the second time point and the upper limit value and a second result which is a difference between a power value of the distributed power system measured at the second time point and the lower limit; ≪ / RTI > Generating the discharge command value such that a power value discharged from the battery is a value between the first resultant value and the second resultant value Energy storage system. The method according to claim 1, The PCS can control the SOC (State of Charge) of the battery within a predetermined stable range based on the command value provided from the host controller Energy storage system. The method according to claim 1, The host controller may be a PMS (Power Management System) or an EMS (Energy Management System) Energy storage system. The method according to claim 1, Wherein the reference value calculating unit updates the reference value every predetermined period, The upper and lower limit value setting unit updates the upper limit value and the lower limit value of the combined power target value based on the updated reference value every predetermined period Energy storage system. An energy storage system coupled to a grid and a distributed power system, A PCS (Power Condition System) for managing power of the distributed power system and the system; A battery charged and discharged by the PCS; And And an upper controller for generating a command value for controlling charge / discharge of the battery based on the power value developed in the distributed power supply system and providing the generated command value to the PCS, Wherein the host controller comprises: A reference value calculation unit for calculating a reference value based on a power value developed in the distributed power system at a first time point and a power value charged / An upper and lower limit value setting unit for setting an upper limit value and a lower limit value of the combined power target value of the distributed power system and the battery based on the calculated reference value, Calculates a power generation slope based on the power values of the distributed power system measured at the first point of time and the second point of time after the first point of time, And a command value generator for generating the command value so that the command value becomes a value of Energy storage system. 9. The method of claim 8, Wherein the command value generating unit comprises: Calculating an estimated power value of the distributed power system at a third time point after the second time point based on the power generation amount slope when the power generation amount slope is an increasing slope, A charging command value associated with the charging of the battery, Calculating a predicted power value of the distributed power system at a third time point after the second time point based on the power generation amount slope when the power generation amount slope is a decreasing slope, The discharge command value associated with the discharge of the battery Energy storage system. 10. The method of claim 9, Wherein the command value generator generates the command value when the power value of the distributed power system measured at the second time point is equal to or greater than the upper limit value, Calculating a first result value that is a difference between a power value of the distributed power system measured at the third time point and the upper limit value, And generates the charging command value so that the power value charged by the battery becomes the first resultant value Energy storage system. 10. The method of claim 9, Wherein the command value generator generates the command value when the power value of the distributed power system measured at the second time point is less than the lower limit value, Calculating a second result value that is a difference between the power value of the distributed power system and the lower limit value measured at the third time point, And generates the discharge command value so that the power value discharged from the battery becomes the second resultant value Energy storage system. 10. The method of claim 9, A time difference between the first time point and the second time point is a first time, The time difference between the second time point and the third time point is N times the first time point, N is a natural number of 2 or more Energy storage system. An energy storage system coupled to a grid and a distributed power system, A PCS (Power Condition System) for managing power of the distributed power system and the system; A battery charged and discharged by the PCS; And And an upper controller for generating a final command value for controlling charge / discharge of the battery based on the power value generated in the distributed power source system and providing the generated final command value to the PCS, Wherein the host controller comprises: A reference value calculation unit for calculating a reference value based on a power value developed in the distributed power system at a first time point and a power value charged / An upper and lower limit value setting unit for setting an upper limit value and a lower limit value of the combined power target value of the distributed power system and the battery based on the calculated reference value, A command value generator for generating the initial command value so that the combined power target value becomes the lower limit value or the upper limit value based on a power value of the distributed power system measured at a second time point after the first time point; And a command value correcting unit for correcting the initial command value to generate the final command value such that the combined power target value is larger than the lower limit value and smaller than the upper limit value Energy storage system. 14. The method of claim 13, Wherein the command value generating unit comprises: Generating an initial charge command value related to charging of the battery among the initial command values when the power value of the distributed power system measured at the second time point is not less than the upper limit value, And generates an initial discharge command value related to discharge of the battery among the initial command values when the power value of the distributed power system measured at the second time point is not more than the lower limit value Energy storage system. 15. The method of claim 14, Wherein the command value generator generates the command value when the power value of the distributed power system measured at the second time point is equal to or greater than the upper limit value, Calculating a first result value that is a difference between a power value of the distributed power system measured at the second time point and the upper limit value, And generates the initial charge command value based on the first resultant value Energy storage system. 16. The method of claim 15, Wherein the command value correcting unit is operable to correct the command value based on the initial charge command value supplied from the command value generator so that the power value charged by the battery is greater than the first result value, And generates a final charge command value Energy storage system. 15. The method of claim 14, Wherein the command value generator generates the command value when the power value of the distributed power system measured at the second time point is less than the lower limit value, Calculating a second result value that is a difference between the power value of the distributed power system and the lower limit value measured at the second time point, And generates the initial discharge command value based on the second resultant value Energy storage system. 18. The method of claim 17, The command value correcting unit may correct the command value of the battery based on the initial discharge command value supplied from the command value generator so that the power value discharged from the battery is greater than the second result value And generates a final discharge command value Energy storage system.

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