KR102503382B1 - Method for power management of Energy Storage System connected renewable energy - Google Patents

Abstract

The present invention relates to a management method of an energy storage system associated with a renewable energy power generation facility and, more specifically, to a management method of an energy storage system associated with a renewable energy power generation facility to efficiently store power produced from a renewable energy power generation facility. According to the present invention, by operating the energy storage system in consideration of charge/discharge amounts, time and the like of a battery according to characteristics of a renewable energy power generation system, there is an effect of increasing efficiency of storage and consumption of energy.

Description

Method for power management of Energy Storage System connected renewable energy

The present invention relates to a management method for an energy storage system associated with a renewable energy generation facility, and more particularly, to an energy storage associated with a new and renewable energy generation facility for efficiently storing power generated by a new and renewable energy generation facility. It is about how to manage the system.

In general, new and renewable energy is a combination of new energy and renewable energy, and refers to energy that is used by converting existing fossil fuels or converted into renewable energy including sunlight, water, precipitation, and biological organisms.

Renewable energy includes sunlight, solar heat, bio, wind power, and hydropower, and new energy includes fuel cells and hydrogen energy.

ESS (Energy Storage System) connects a renewable energy generation system represented by solar power and a power storage system. It stores renewable energy or surplus power from the power system in a battery that can be charged and discharged, and supplies power to loads when needed. system that supplies Korean Patent Publication No. 2013-0138611 discloses an energy storage system associated with a renewable energy generation system.

In general, a renewable energy generation system-linked energy storage system charges a battery with renewable energy or grid power, and supplies power to a load through any one of renewable energy, grid, and battery when power is required to be supplied to a load. do. Interest in renewable energy and energy storage systems is gradually increasing, and system complexity is gradually increasing as the energy storage system charges a battery and supplies power to a load through a plurality of power sources. Therefore, a technology that can be optimized according to the characteristics of renewable energy and batteries and can more efficiently manage energy storage and consumption is required.

KR 10-2017-0095580 A KR 10-2020-0126816 A

An object of the present invention to solve the above problems is to provide a management method of an energy storage system associated with a renewable energy generation facility for efficient storage according to the characteristics of new and renewable energy and batteries.

The present invention, conceived to solve the above problems, provides a battery that is charged in connection with an external power grid that supplies power to a power load that consumes power, a BMS (Battery Management System) for managing charge or discharge of the battery, power supply and In the management method of an energy storage system (ESS) including an energy storage facility equipped with a PCS (Power Conditioning System) for management and a plurality of renewable energy generation facilities that produce electrical energy from renewable energy, the PCS In the power management method, the predicted power consumption of the power load and the predicted production power of the renewable energy generation facility are calculated (S100), and after the step S100, setting a charge / discharge schedule of the battery Step (S150), storing type and characteristic information of the renewable energy generation facility (S200), and predicting the production power of the renewable energy generation facility that can be produced before the battery is discharged (S300). ), calculating the required amount of charge before discharging the battery (S400), determining whether the amount of power shortage according to the required amount of charge of the battery is greater than or equal to a set value (S500), and if the amount of power shortage is smaller than the set value Determining whether the battery can be fully charged with the power produced by the renewable energy generation facility (S600), and changing the charging/discharging schedule of the battery according to the result of the step S600, wherein the S500 In step S510 of maintaining the charge/discharge schedule of step S150 if the power shortage is greater than or equal to the set value, charging the battery according to the charge/discharge schedule (S700), and If the battery cannot be fully charged with the power produced by the renewable energy generation facility, the step of changing the charge/discharge schedule of step S150 (S800), and supplying from the renewable energy generation facility and the power grid after the step S800. with all the power A step of charging the battery with (S900) is further included.

At the time when the charging of the power grid power starts after the step S900, the battery cells 311 of the first ratio among all the battery cells 311 included in the battery 310 are used for charging the power grid power. A step S910 is further included.

After the step S910, the BMS compares the amount of power charged in the battery cells 311 of the first ratio with a target charging amount to determine whether the battery 310 can be fully charged before the battery discharge time (S920) more includes

If it is determined that full charge is not possible with only the battery cells 311 of the first ratio after the step S920, the BMS converts the battery cells 311 of the second ratio to be additionally used for charging the grid power ( S930) is further included.

After the step S930, a step of checking whether the battery cell 311 converted to be used for charging the grid power is fully charged (S940), and the power in the battery cell 311 is not close to full charge. The step of continuing charging in the failed state (S950) is further included.

After the step S940, when the battery cell 311 approaches full power, a step S960 of stopping charging of the grid power by performing a reduction operation of the battery cell 311 is further included.

According to the present invention, the efficiency of energy storage and consumption is improved by operating an energy storage system in consideration of the charge/discharge amount and time of a battery according to the characteristics of a renewable energy generation system.

1 is a block diagram showing battery charging according to an energy storage system of the present invention;
Figure 2 is a block diagram showing a battery discharge according to the energy storage system of the present invention.
3 is a graph showing an example of a charge/discharge cycle according to the power management method of the present invention.
Figure 4 is a flow chart showing the process of the energy management method of the present invention.
5 is a flowchart illustrating a power grid charging conversion process;
6 is a block diagram showing the structure of a battery cell inside a battery;

Hereinafter, a "management method of an energy storage system associated with a renewable energy generation facility" (hereinafter referred to as 'management method') according to an embodiment of the present invention will be described with reference to the drawings.

1 is a block diagram showing battery charging according to the energy storage system of the present invention, FIG. 2 is a block diagram showing battery discharging according to the energy storage system of the present invention, and FIG. 3 is a power management method according to the present invention. A graph showing an example of a charge/discharge cycle according to FIG. 4 is a flow chart showing the process of the energy management method of the present invention, FIG. 5 is a flow chart showing the power grid charge conversion process, and FIG. block diagram shown.

As shown in FIGS. 1 and 2 , the energy storage system according to an embodiment of the present invention may be largely composed of at least one renewable energy generation facility 200 and an energy storage facility 300 . The renewable energy generation facility 200 serves to supply power to the energy storage facility 300 or the power load 400 together with the power supplied from the power grid 100 .

The power grid 100 is a power grid that supplies power generated by conventional power generation systems such as thermal power, hydropower, and nuclear power, and the power load 400 refers to various facilities such as homes, buildings, and factories that consume power.

The renewable energy power generation facility 200 is a power generation facility using renewable energy such as solar light, wind power, tidal power, biomass, and the like, and different types of power generation facilities may be applied depending on the installation location. At least one renewable energy generation facility 200 is applied, and preferably, a plurality of facilities suitable for regional characteristics are applied.

The photovoltaic power generation facility 210 may include a solar cell, a power converter that converts the electrical energy produced by the solar cell from direct current to alternating current and connects it to a power system, and a storage device that temporarily stores the produced electrical energy. there is. Since the configuration of the photovoltaic power generation facility is a well-known technology, a detailed description thereof will be omitted.

The wind power generation facility 230 may be composed of blades, an energy conversion device that converts the kinetic energy of wind into electrical energy by the blades, a power transmission device, a control device, etc. do it with

The energy storage facility 300 has a battery 310 that can be charged or discharged, charges the battery 310 to store energy, and discharges the battery 310 to transfer the stored energy to the power grid 100 or a power load ( 400) to supply power. In general, the energy storage facility 300 may include a Battery Management System (BMS) for managing charge or discharge of the battery 310 and a Power Conditioning System (PCS) for power supply and management.

The battery 310 may include various types of batteries such as secondary batteries, and may also include all-solid-state batteries. Efficient battery management is possible by changing the battery charge/discharge plan according to the type and characteristics of the battery, and a short-term power management plan can be established by additionally obtaining information on the remaining capacity of the battery. In addition, the battery 140 has a function of an energy storage for storing energy by charging power supplied through the renewable energy power generation facility 200 or the power grid 100, and the energy stored through discharging to the power load 400 or It functions as an energy source supplied to the power grid 100.

The PCS 350 is a power converter, and serves to convert alternating current and direct current, as well as converting voltage, current, and frequency. The PCS 350 supplies the energy supplied from the power plant through the power grid 100 to the power load 400 or charges the battery 310, or supplies the energy supplied from the renewable energy generation facility 200 to the power load ( 400) or charged to the battery 310. Alternatively, energy stored by discharging the battery 310 is supplied to the power load 400 or the power grid 100 to perform power management. At this time, charging/discharging of the battery 310 is operated in consideration of the type and characteristic information of the battery 310 .

In addition, the PCS 350 may monitor the power consumed by the power load 400 and store and retain the information.

The BMS 330, as a battery management system, controls the charge/discharge amount of the battery 310 to an appropriate level by sensing the voltage, current, temperature, etc. of the battery, as well as performs cell balancing of the battery 310, The remaining capacity of the battery 310 is determined. In addition, the BMS 330 protects the battery 310 through an emergency operation when danger is detected. The BMS 330 stores type and characteristic information of the battery 310 and manages charging and discharging according to the characteristics of the battery 310 .

The power load 400 may receive power from the power grid 100 and the battery 310 of the energy storage system, and may receive power only through either the power grid 100 or the battery 310 depending on power conditions. there is.

As shown in FIG. 4, the PCS 350 acquires power consumption demand and power status information from the aforementioned external power server (S50), and obtains demand information such as past and recent power consumption from the power load 400. can be obtained Based on this information, the PCS 350 calculates predicted power consumption and predicted production power (power consumption and production power calculation step, S100), and can generate a battery charge/discharge schedule (S150) Battery charge/discharge It should be understood that the subject of schedule creation, change, and control is performed in the PCS 350.

For example, as shown in FIG. 3 , the discharge (power consumption) of the battery 310 is scheduled at 2:00 pm to 4:00 pm, which is the peak time of power consumption, and the charging of the battery 310 is performed in a time zone according to the charging means. It is possible to set a schedule to charge by changing.

Among renewable energy facilities, since wind power is generated most of the day, charging of the battery 310 using wind power can be performed without time constraints. Solar power generation is possible from sunrise to sunset, and the battery 310 can be charged by generating maximum power around noon, which is the time zone. The type of the renewable energy power generation facility 200 and the corresponding characteristic information are stored in the PCS 350 (renewable energy characteristic information storage step, S200) to predict the production power that can be produced until the battery 310 is discharged. It can be utilized (production power prediction step, S300)

The charging of the battery 310 using the power grid 100 may be scheduled so that the power rate is low, for example, before 9:00 am when the middle load rate is applied. It can be set to charge on time. Since wind power generation and solar power generation are also performed during the charging time of the battery 310 using the power grid 100 , the generated power may be supplied to the battery 310 . During the charging time of the battery 310 using the power grid 100, the power generated by the photovoltaic power generation facility 210 and the wind power generation facility 230 may be sent to the battery 310 or may be sent to the power load 400. may be

Under normal circumstances, power produced through wind power generation and photovoltaic power generation and power advanced through the power grid 100 are supplied to the power load 400, and the charge/discharge schedule of the battery 310 set by the PCS 350 The battery 310 is charged accordingly.

The PCS 350 may predict the amount of power generation by renewable energy facilities from 8:00 am to 2:00 pm in order to manage the charging/discharging schedule of the battery 310 (S300, see FIG. 3) Amount of power generation by renewable energy facilities This can be achieved through simulation using the average value of power generation for the previous 10 days or annual average data.

When the amount of power generated by the new renewable energy facility is predicted, the amount of charge of the battery 310 at around 2:00 pm before discharging of the battery 310 starts is calculated. After calculating the power shortage required to fully charge the battery 310 to 100% before discharging the battery 310, the battery charging requirement may be calculated (battery charging requirement calculation, S400).

If the power shortage is equal to or greater than a preset value (power shortage determining step, S500), the battery 310 can be fully charged before being discharged, and thus the charging/discharging schedule of the battery 310 does not need to be changed. If the power shortage is more than a preset value (S500), based on the calculated value, it is calculated whether the battery 310 can be 100% fully charged by the renewable energy facility (determining whether the battery can be fully charged with renewable energy, S600) Battery The remaining amount of power (D1) insufficient until fully charged in 310 is calculated as kWh.

If the battery 310 can be fully charged by the renewable energy facility before the start of discharging (if YES in S600), the battery 310 is charged according to the charging schedule described above (charging step, S700)

However, even though the battery 310 is charged using the power grid 100 in the lowest load rate range, there may occur a case in which the battery 310 cannot be fully charged by the renewable energy facility until the battery 310 starts to be discharged. This case may be caused by meteorological factors, such as when there is no wind or when the weather is cloudy, or may be caused by various factors, such as a failure of a power system, a planned power outage, or a sudden increase in power load.

In this case (if NO in S600), the charging schedule is changed so that the battery 310 is charged by additionally inputting the power of the power grid 100 even if it is not the lowest load charge time for smooth power supply through the battery 310. (Charging / discharging schedule change step, S800) The amount of power to be charged through the power grid 100 can be calculated by dividing the amount of power generation (kW) generated from the renewable energy generation facility 200 by the amount of remaining insufficient power (D1) by time. (Renewable energy generation amount + D1/1hr) By referring to the calculated value, the battery 310 additionally uses the power supplied from the power grid 100 in addition to the power supplied from the renewable energy facility until the discharge time of the battery 310. Charge (S900)

However, since the time to charge the battery 310 with the power supplied from the power grid 100 is not the time when the lowest load rate is charged, the power supplied from the power grid 100 before charging the battery 310 (S900). A decision-making request may be made to a manager or a server to determine whether to charge the battery 310 with the power that is desired (S850). Depending on the remaining amount of the battery 310, whether or not the battery 310 is charged through the power grid 100 may be pre-data and stored in the server, or a manager may directly determine whether to proceed with step S900 according to the situation. .

After the battery 310 is fully charged (S700, S900), the battery 310 is discharged in a fully charged state, and during peak hours when the battery 310 is discharged, the battery 310 is charged with power and renewable energy. Both the power produced by the facility and the power supplied from the power grid 100 are supplied to the power load 400 (S1000). In some cases, the power generated by the facility is supplied to the power load 400, and the remaining power is supplied to the power grid 100 and sold. It can generate revenue or maintain it with the remaining power of the battery 310 .

In the process of charging the battery 310 using renewable energy and power supplied from the power grid 100 (S900), the ratio of the battery 310 supplied with power from the power grid 100 can be sequentially increased. there is. That is, in order to minimize the use of relatively expensive power of the power grid 100, the battery 310 is sequentially connected to the power grid 100 at a predetermined rate.

As shown in FIG. 5, when battery charging starts with grid power (S900), the energy storage facility 300 first configures a circuit so that a predetermined ratio of battery cells 311 is used for charging of grid 100 power. (S910) As shown in FIG. 6, the battery cell 311 refers to an individual power storage constituting the battery 310. The battery cells 311 are manufactured in various numbers according to the type and capacity of the battery 310, and the BMS 330 controls the amount of power charged in each cell, thereby enabling the effective use of the energy storage facility 300, The life of the battery 310 is extended.

The energy storage facility 300 uses a first ratio of battery cells 311 among all battery cells 311 included in the battery 310 at the time when charging of power from the power grid 100 is started. Use it for charging power. In the present invention, the first ratio is set to 3% to 7%, most preferably set to 5%.

In this state, the BMS 330 compares the amount of power charged in each battery cell 311 with a target charging amount to determine whether or not the battery 310 can be fully charged before the battery discharge time (S920).

If it is determined that the battery cells 311 of the first ratio converted to the power grid 100 are charged with more than a certain level of power and can be fully charged before the discharge time, charging continues in the current state. (S950) That is, Since full charge is possible only by using the first ratio of battery cells 311, conversion of additional battery cells 311 is not required.

However, if it is determined that full charge is not possible with only the battery cells 311 of the first ratio, the BMS 330 additionally converts the battery cells 311 . That is, the circuit is switched to additionally charge the battery cells 311 of the second ratio with power supplied from the power grid 100 (S930).

In the present invention, the second ratio is set to 1% to 5%, most preferably 3%.

In this state, the battery cells 311 as many as the sum of the first ratio and the second ratio are switched to be used for charging power supplied from the power grid 100 . Therefore, more power can be supplied from the power grid 100 and charged.

The BMS 330 checks whether the power is fully charged in the battery cell 311 converted to that used for charging the power of the power grid 100 (S940). When approaching the state, the battery cell 311 is reduced. (S960) In a state that is not close to fully charged, charging continues. (S950)

In the present invention, when the amount of power charged in the battery cell 311 exceeds 90% of the total capacity, it is determined that the battery cell 311 is close to being fully charged. When the amount of power charged in the battery cell 311 exceeds 95%, the time taken to charge to 100% further increases. In addition, if the battery cell 311 is charged with 100% power, the battery 310 used in the energy storage device may be damaged or its lifespan may be shortened. let it do

The BMS 330 transfers the second ratio of battery cells 311 from the power grid 100 power supply circuit when the amount of power charge of the battery cells 311 used for charging the power of the power grid 100 exceeds 95% of the total. By separating, the original charging method is restored (S960). That is, the battery cells 311 of the second ratio are connected so that they can be used for charging of renewable energy.

In this state, the battery cells 311 of the first ratio among all the battery cells 311 are being used for charging the power of the power grid 100 .

And when the charging continues in that state and the charging of the battery cell 311 is completed, the charging of the electric power of the power grid 100 is terminated, and the circuit is switched to be used for charging with renewable energy again (S970).

Through this process, it is possible to reduce operating costs while minimizing the use of relatively expensive power from the power grid 100 to charge the battery 310, and to extend the lifespan of the battery 310 through efficient use of the battery 310. there will be

Although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, the technical configuration of the present invention described above is another specific form without changing the technical spirit or essential features of the present invention by those skilled in the art to which the present invention belongs. It will be understood that it can be implemented with Therefore, the embodiments described above should be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the claims to be described later rather than the detailed description, and the meaning and scope of the claims and All changes or modified forms derived from the equivalent concept should be construed as being included in the scope of the present invention.

100: power grid 200: renewable energy power generation facility
300: energy storage facility 400: power load

Claims (6)

Equipped with a battery that is charged by being connected to an external power grid that supplies power to power loads that consume power, a BMS (Battery Management System) for battery charging or discharging management, and a PCS (Power Conditioning System) for power supply and management. In the management method of an energy storage system (ESS) including an energy storage facility and a plurality of renewable energy power generation facilities that produce electrical energy from renewable energy,
The power management method in the PCS,
Calculating the predicted power consumption of the power load and the predicted production power of the renewable energy generation facility 200 (S100);
Setting a charge/discharge schedule of the battery after the step S100 (S150);
Storing type and characteristic information of the renewable energy power generation facility 200 (S200);
Predicting the production power of the renewable energy power generation facility 200 that can be produced before the battery is discharged (S300);
Calculating a required charge amount before discharging the battery (S400);
Determining whether the amount of power deficiency according to the required amount of charge of the battery is greater than or equal to a set value (S500);
If the power shortage is less than a set value, determining whether the battery can be fully charged with the generated power of the renewable energy generation facility 200 (S600);
Maintaining the charge/discharge schedule of step S150 when the power shortage amount is greater than or equal to the set value in step S500 (S510);
Charging the battery according to the charge/discharge schedule (S700);
Changing the charge / discharge schedule of the step S150 when the battery cannot be fully charged with the power produced by the renewable energy generation facility 200 in step S600 (S800);
After the step S800, charging the battery with power supplied from the renewable energy power generation facility 200 or the power grid 100 (S900);
When the step S900 starts, the BMS transfers battery cells 311 of a first ratio among all battery cells 311 included in the battery 310 from the power grid 100 at the time when charging of the battery starts. A step of converting the supplied power to be used for charging (S910);
The BMS compares the amount of power charged in the battery cells 311 of the first ratio with a target charging amount to determine whether or not the battery 310 can be fully charged before the battery discharge time (S920);
In step S920, if it is determined that full charge is not possible with only the battery cells 311 of the first ratio, the BMS additionally uses the battery cells 311 of the second ratio to charge the power supplied from the power grid 100. Including the step of switching to (S930),
The first ratio is 5%, and the second ratio is 3%, characterized in that, a management method of an energy storage system associated with a renewable energy power generation facility. delete delete delete According to claim 1,
A step of confirming whether the battery cell 311 converted to be used for charging the power supplied from the power grid 100 after the step S930 is fully charged with power (S940);
Further comprising the step (S950) of continuing to charge the battery cell 311 in a state where the power is not close to full charge, the management method of the energy storage system associated with the renewable energy generation facility. According to claim 5,
In step S940, if the amount of power charged in the battery cell 311 exceeds 95% of the total capacity, the BMS determines that the state is close to full power, and then the battery cell 311 of the second ratio Stopping the charging of the power supplied from the power grid 100 by performing a reduction operation, and allowing the battery cells 311 of the first ratio to be continuously used for charging the power of the power grid 100 (S960);
Switching the circuit so that the battery cells 311 of the second ratio, in which power charging of the power grid 100 is stopped, is again charged with power supplied from the renewable energy power generation facility 200 (S970) Further comprising , Management method of energy storage system linked with renewable energy generation facilities.

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