KR102270913B1 - Apparatus and method for controlling energy storage system - Google Patents

Abstract

The present invention relates to an apparatus and method for controlling a power storage system, and in a control apparatus for a power storage system including a storage unit for storing electric energy and a conversion unit connected to a power system, monitoring and charging/discharging the state of a battery A storage unit including a master BMS (Battery Management System) for controlling, and at least one or more storage groups, converting AC power of a power system into DC power or converting DC power of a battery into AC power, at least one or more a power converter (PCS) configured including a switching element, and a converter including a PCS controller; and a control unit for instantaneously charging/discharging the storage unit by sequentially outputting control signals according to a preset order to each storage group of the storage unit and a switching element of the power converter according to output characteristics required by the power system.

Description

Apparatus and method for controlling power storage system {APPARATUS AND METHOD FOR CONTROLLING ENERGY STORAGE SYSTEM}

The present invention relates to an apparatus and method for controlling a power storage system, and more particularly, by charging/discharging a secondary battery used in the power storage system using instantaneous charge/discharge characteristics to improve the operating characteristics of the power storage system, At the same time, it relates to a control device and method for a power storage system that can obtain the effect of extending the life of a secondary battery.

In general, compared to power storage devices with mechanical properties such as pumped-water power generation or flywheels, it is the most popular type of secondary battery (that is, a battery that is charged and used semi-permanently) by converting electrical energy into chemical energy to store energy. The major disadvantages are that the life expectancy is short due to the limited number of charge/discharge and the instantaneous output is relatively low.

First, the main cause of the decrease in the lifespan of the secondary battery is that the characteristics of the positive and negative electrodes change in the process of repeating charging/discharging several times, or the movement of cations in the electrolyte is impaired due to the phase change of the electrolyte. to be. The aging of the anode and cathode elements and the phase change of the electrolyte are the size and duration of the charge/discharge current, the high voltage out of the normal range, the high/low temperature operating environment, and the charge/discharge depth (DoD, Depth of Discharge), It is affected by the discharge interval and frequency.

Therefore, in order to prevent a change in the characteristics of the secondary battery and extend the lifespan, the operation must be carried out with the operating conditions so that the above-mentioned conditions (eg, low voltage, normal temperature, low DoD, low output current) do not deviate from the set operating range as much as possible. do.

Research and development are in progress for a method to extend the lifespan by maintaining these operating conditions at all times.

Next, the reason why the instantaneous output of the secondary battery is low is closely related to the above-described lifespan. That is, in order to rapidly charge/discharge a secondary battery in which energy is converted through a chemical reaction, the chemical reaction must be instantaneously rapid. In this process, the aging of the anode/cathode element and the change of the electrolyte are easily generated. Therefore, not maintaining high output by rapid charging/discharging for a long time can reduce the life span, and for this reason, most secondary batteries limit the current strength in constant output mode operation.

For the above reasons, in the case of a power storage system that maintains high output for a relatively short period of time and requires charging/discharging more than tens of times a day, a large amount of batteries are required to maintain output and store energy, which increases the cost of secondary batteries and increases the frequency of high output The lifespan is shortened due to charging/discharging, making it difficult to achieve economic feasibility in actual application.

As described above, the lifespan of the secondary battery is greatly affected by the environmental conditions, operating conditions, and the number of times of charge/discharge in which the battery is used. In general, as the energy of the self-rated capacity is used larger than the rated charge/discharge current ratio, the lifespan of the secondary battery rapidly decreases and the operating temperature rises. Here, the rated charge/discharge condition usually means constant current charging/discharging.

On the other hand, the conventional power storage system is usually composed of a secondary battery, a battery management system (BMS), and a power conversion device, and is also configured according to the constant current characteristics of the secondary battery used therein, When discharging, all batteries are used at once and are operated in a manner of charging/discharging with a predetermined current or output. As described above, the conventional power storage device is operated in a constant current charging/discharging method that uses the energy of the rated capacity of the secondary battery used therein at the rated charge/discharge current ratio or smaller than that. Due to the problem of shortening the lifespan of the secondary battery, it is difficult to operate with an output greater than a predetermined constant current.

The background technology of the present invention is disclosed in Republic of Korea Patent No. 10-1097259 (registered on December 15, 2011, apparatus and control method for power storage).

The present invention was created to solve the above problems, and by charging/discharging the secondary battery used in the power storage system using instantaneous charge/discharge characteristics, the operation characteristics of the power storage system are improved and the secondary battery An object of the present invention is to provide a control device and method for a power storage system that can achieve the effect of extending the life of the power storage system.

A control device for a power storage system according to an aspect of the present invention is a control device for a power storage system including a storage unit for storing electrical energy and a conversion unit connected to a power system, and performs battery state monitoring and charging/discharging. a storage unit including a master battery management system (BMS) for controlling, and at least one storage group; A power converter that converts AC power of a power system into DC power or converts DC power of a battery into AC power, a power converter (PCS) including at least one switching element, and a converter including a PCS controller; and a control unit for instantaneously charging/discharging the storage unit by sequentially outputting control signals according to a preset order to each storage group of the storage unit and a switching element of the power converter according to output characteristics required by the power system. characterized in that

In the present invention, the storage group of the storage unit is characterized in that it is configured as a multiple of the number of at least one or more switching elements constituting the power converter.

In the present invention, each of the switching elements is characterized in that it is configured to correspond to each storage group of the storage unit 1:1.

In the present invention, the control unit is characterized in that it controls the charging/discharging of the storage group according to the energization timing of each switching element of the power converter corresponding to each storage group of the storage unit 1:1. .

In the present invention, the storage group, the storage module having at least one or more battery cells (Cell); and at least one or more slave BMSs respectively controlling the state monitoring and charging/discharging of the storage module according to the control of the master BMS.

In the method for controlling a power storage system according to another aspect of the present invention, the control method of the power storage system including a storage unit for storing electric energy and a conversion unit connected to the power system, the control unit is a preset operation strategy by an operator calculating an output range of the power storage system based on at least one of , an operating condition, and a storage state of the storage unit; determining, by the control unit, an output amount of the power storage system based on the state of the power system and power market information; selecting, by the control unit, an operation order of each storage group of the storage unit and each switching element of the conversion unit according to the output amount of the power storage system; transmitting, by the control unit, a control signal to the BMS (Battery Management System) of the storage unit and the PCS controller of the converting unit at the same time; The power converter of the conversion unit receiving the control signal converts DC power into AC power by on/off control of each switching element according to a preset sequence, and the BMS of the storage unit receiving the control signal receives the control signal controlling on/off of a storage group corresponding to the switching element; and outputting, by the converter, an output converted through on/off of each switching element of the power converter paired 1:1 with each storage group of the storage to the power system.

In the present invention, in the step of converting DC power into AC power by on/off control of the switching element, the power converter sequentially controls on/off the switching element according to the control of the controller, but each switching element It is characterized in that the control is performed so that the on/off period of the overlapping period occurs for a predetermined period of time.

In the present invention, the storage group of the storage unit is characterized in that it is configured as a multiple of the number of at least one or more switching elements constituting the power converter.

In the present invention, in the step of converting DC power to AC power by controlling on/off of the switching element, the controller includes: each of the switching elements of the power converter corresponding to 1:1 with each storage group of the storage unit. In order to control the charging/discharging of the storage group according to the on/off timing, and to allow each storage group to have a rest period for a predetermined period of time, the OFF time of the switching element corresponding to each storage group is 1:1. It is characterized in that it is maintained for a predetermined period of time.

In the present invention, the storage state of the storage unit is at least one of the amount of power and operation condition information, the output range of the power storage system is at least one of the maximum output and output time information, and the state of the power system is frequency, variability, and output At least one of the control signal information, the power market information is characterized in that it includes at least one of price and volatility information.

The present invention improves the operating characteristics of the power storage system and increases the lifespan of the battery by charging/discharging the secondary battery used in the power storage system using the instantaneous charge/discharge characteristic.

1 is an exemplary diagram showing a schematic configuration of a control device of a power storage system according to an embodiment of the present invention.
2 is an exemplary view showing a more detailed configuration of a storage unit in FIG. 1 .
3 is an exemplary view showing a more detailed configuration of the conversion unit in FIG. 1 .
4 is a flowchart illustrating a control method of a power storage system using instantaneous charge/discharge characteristics according to an embodiment of the present invention.
5 is an exemplary diagram for explaining in more detail the operations of steps S104 and S105 in FIG. 4 .
6 is an exemplary diagram showing a power converter (PCS) of a power storage system operated by a control method according to an embodiment of the present invention and voltages output from each storage group in a graph;
7 is an exemplary view for explaining an ideal DC power applied to the switching element of the conversion unit in FIG. 1 .
8 is an exemplary view showing a blank section of DC power generated in the switching element of the converter in FIG. 1 .
FIG. 9 is an exemplary view for explaining an operation of overlapping DC power output of a storage unit so that an output blank does not occur in FIG. 8;
10 is an exemplary diagram for explaining a method of controlling an instantaneous output of a storage group while maintaining a continuous output of the power storage system according to another embodiment of the present invention.
11 is an exemplary diagram for explaining a method of controlling an instantaneous output of a storage group while maintaining a continuous output of a power storage system according to another embodiment of the present invention;

Hereinafter, an embodiment of an apparatus and method for controlling a power storage system according to the present invention will be described with reference to the accompanying drawings.

In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of the user or operator. Therefore, definitions of these terms should be made based on the content throughout this specification.

Unlike the constant current charging/discharging method of the secondary battery described in the background technology, when instantaneous charging/discharging is performed intermittently in a very short time, the self-rated current It is known that the lifespan characteristics are rather improved while passing a current corresponding to a maximum of 10 times. The reason is that when charging/discharging is performed in the form of intermittent pulses, a rest period can be secured for a considerable period of time until charging/discharging is performed again, so that the positive/negative electrode device and the electrolyte can have time to recover. For reference, the holding time of instantaneous output during pulse charge/discharge is very short, usually several to tens of ms.

The present invention improves the operating characteristics of an Electric Energy Storage System (ESS) (or power storage device) by using the pulsed current charging/discharging characteristics of the secondary battery as described above, and at the same time It is also possible to obtain the effect of extending the life of the secondary battery used.

(Example 1)

1 is an exemplary diagram showing a schematic configuration of an apparatus for controlling a power storage system according to an embodiment of the present invention.

As shown in FIG. 1 , the power storage system (ESS) (or power storage device) according to the present embodiment includes a storage unit 200 for storing energy and a conversion unit 300 connected to the power system. .

The storage unit 200 is a storage facility (or storage means) such as a battery that actually stores electrical energy (eg, storage group 1 to storage group N) and a BMS for monitoring the state of the storage facility and controlling charging/discharging. (Battery Management System). The BMS includes a master BMS (M-BMS) and a plurality of slave BMSs (S-BMS) (see FIG. 2 ).

The converter 300 is a power converter (PCS: Power) that converts AC power of a general power facility such as a transformer, a circuit breaker (not shown), and a power system into DC power or converts DC power of a battery into AC power. Conditioning System), and a PCS controller 320 (see FIG. 3 ) called a Power Management System (PMS) or an Energy Management System (EMS).

In this embodiment, characteristically, by configuring the storage unit 200 as a unit module group (storage group) in multiples of the number of switching elements (SW1 to SWN) constituting the power converter (PCS) for the instantaneous charge/discharge control , control so that charging/discharging of the unit module group (storage group) (eg, battery cell, battery module) is performed according to the energization timing of the switching elements SW1 to SWN of the power converter (PCS).

The control unit 100 sequentially outputs a control command (or a control signal) to the storage unit 200 and the conversion unit 300 according to the output characteristics required by the system (power grid).

The storage group (group 1 to group N) of the storage unit 200 and the switch (or switching element) of the conversion unit 300 each correspond to 1:1, and the control command output from the control unit 100 ( control signal), it operates as in the flowchart of FIG. 4 and finally has the output of the waveform as shown in FIG.

2 is an exemplary view showing a more detailed configuration of the storage unit in FIG. 1 .

As shown in FIG. 2 , the storage unit 200 includes a master BMS (M-BMS, 201) and at least one storage group 210 to 260, and the storage groups 210 to 260 are each Slave BMS (S-BMS, 211, 221, 231, 241, 251, 261), and storage modules (212, 222, 232, 242, 252, 262) having at least one cell (Cell) (unit cell set) ) is included.

At this time, the storage groups 210 to 260 correspond to the individual switching elements SW1 to SW6 of the power converter PCS 310 in a 1:1 ratio, respectively, as shown in FIG. 3 .

3 is an exemplary view showing a more detailed configuration of the conversion unit in FIG. 1 .

As shown in FIG. 3 , the converter 300 includes a power converter 310 and a PCS controller 320 .

The power converter (PCS, 310) includes at least one switching device (SW1 ~ SW6), each of the switching devices (SW1 ~ SW6), as shown in FIG. 2, each storage group (210 ~ 260) ) is 1:1, respectively.

4 is a flowchart illustrating a control method of a power storage system using instantaneous charge/discharge characteristics according to an embodiment of the present invention.

However, in this embodiment, the process and control flow of converting DC power into AC power in the power converter (PCS) are the same as the control process of a general power converter, and since it is out of the scope of the present invention, a description thereof will be omitted. Hereinafter, in the present embodiment, a method for controlling the operation of the switching elements of the power converter (PCS) to instantaneously output the output control of the storage group configured as a multiple of the number of switching elements of the power converter (PCS).

As shown in FIG. 4 , the control unit 100 (or internal monitoring unit) monitors the system state of the power storage system. That is, by comparing the operation strategy and operating conditions preset by the operator, and the storage state (eg, amount of power, operating conditions) of the storage unit 200 (or storage means), the output range of the power storage system (eg, maximum output, output time) is calculated (S101).

The control unit 100 receives the state (eg, frequency, volatility, output control signal, etc.) of the power grid (power system) and power market information (eg, price, volatility) and finally determines the output amount of the power storage system ( S102).

The control unit 100 selects an operation sequence of each storage group of the storage unit 200 and each switching element of the conversion unit 300 according to the determined output amount of the power storage system (S103).

The control unit 100 simultaneously transmits a control signal to the BMS 201 , 211 , 221 , 231 , 241 , 251 , 261 of the storage unit 200 and the PCS controller 320 of the conversion unit 300 ( S104).

The power converter (PCS, 310) of the converter 300 receiving the control signal converts DC power into AC power by turning on/off control of each switching element according to a preset order. At the same time, the BMSs 201 , 211 , 221 , 231 , 241 , 251 , 261 of the storage unit 200 receiving the control signal input an on/off control signal to each switching element and each storage group corresponding thereto. transmit

In this way, each switching element of the power converter (PCS, 310) receiving the control signal and each storage group paired with each other are controlled to simultaneously perform an on/off operation (S105).

The conversion unit 300 converts the output converted through on/off of each switching element of the power converter (PCS, 310) paired with each storage group of the storage unit 200 to a transformer (see FIG. 1). output to the power system (power grid) through (S106).

Thereafter, the control unit 100 monitors the state (eg, storage capacity change and output) of the storage unit 200 and the conversion unit 300 and feeds it back to step S101 (S107), and the series of operation steps ( S101 to S106) are repeated.

FIG. 5 is an exemplary diagram for explaining the operations of steps S104 and S105 in more detail in FIG. 4 .

As shown in FIG. 5 , each storage group (group 1 to group 6) of the storage unit 200 and each switching element SW1 to SW6 of the power converter (PCS, 310) correspond to 1:1. The operation process is shown as an example.

That is, as described with reference to FIGS. 2 and 3 , each of the storage groups (group 1 to group 6) and each switching element SW1 to SW6 correspond to each other in a 1:1 correspondence to operate on/off.

For example, when the first switching element SW1 is turned on, the first storage group (group 1) is also turned on, and when the first switching element SW1 is turned off, the first storage group (group 1) is also turned off. The remaining switching elements and the storage groups also correspond to each other in a one-to-one correspondence so that an on/off operation is performed.

At this time, in the process where the output of the DC power applied to the conversion unit 300 corresponds to each switching element in a 1:1 operation, as shown in FIG. 7 , the application of DC power without an output gap is ideal, but the actual switching In the process, an output blank as shown in FIG. 8 may occur. Therefore, in the present embodiment, as shown in FIG. 9 , DC power applied to each switching element is overlapped to control so that a void does not occur in the DC power applied to the converter 300 .

7 is an exemplary view for explaining an ideal DC power applied to the switching element of the converter in FIG. 1, and FIG. 8 is a blank section of the DC power generated in the switching element of the converter in FIG. 1 It is an exemplary view, and FIG. 9 is an exemplary view for explaining the operation of overlapping the DC power output of the storage unit so that an output blank does not occur in FIG. 8 .

Meanwhile, FIG. 6 is an exemplary diagram showing a power converter (PCS) of a power storage system operated by a control method according to an embodiment of the present invention and voltages output from each storage group as a graph.

Referring to FIG. 6 , it can be seen that the DC input is converted into a waveform for AC power conversion by the operation of the switching element of the power converter (PCS).

As shown in FIG. 6 , it can be confirmed that each storage group corresponding thereto is turned on/off according to the on/off operation of each switching element.

For example, the first storage group (group 1) is turned on when the first switching element SW1 is turned on, and the first storage group (group 1) is also turned off when the first switching element SW1 is turned off. Able to know. And until the first switching element SW1 is turned on, the first storage group (group 1) has a rest period, and during the rest period, the characteristics of the anode/cathode element and the electrolyte are restored, so that the power storage means such as a secondary battery Lifespan shortening can be prevented.

This rest period can be taken longer by securing the number of storage groups of the power storage system as a multiple of the number of switching elements. For example, if a 10ms rest period is secured by composing a storage group in multiples, it is possible to secure a rest period of 20ms in the case of 2x and 30ms in the case of 3x. In particular, if a multi-level PCS composed of multi-level switching elements constituting a power converter (PCS) is applied, and the storage group of the power storage means (eg, secondary battery) is subdivided according to the characteristics of the power storage means, each power storage means can control the rest period.

In addition, the output size of the storage group is determined by adjusting the instantaneous output current through the control command (control signal) sent from the PMS to the BMS according to the MVA (Mega Volt Ampere) size required by the power system.

For reference, it is known that the instantaneous output current can be safely applied up to 10 times compared to the case of a general lithium ion secondary battery during continuous constant output operation.

In addition, as another embodiment according to the present invention, the configuration of increasing the output and extending the life of the storage means by combining and adjusting the output order of the battery cells, capacitors, magnetic coils, or battery module groups that are the storage means of the storage unit constituting the ESS is also possible

In the first embodiment described above, one storage group is assigned 1:1 for each switching element of the power converter (PCS) to charge/discharge, but two or more storage means groups are assigned to one switching element to charge/discharge. In case of discharging, the instantaneous output can be increased more than twice as compared to allocating one storage group. Depending on the storage capacity, status and characteristics of each storage group, it is also possible to operate the storage groups sequentially or by pre-programming and assigning them. It is possible.

In this case, the method for improving the instantaneous output characteristics of the storage group and adjusting the rest period may be modified and applied as follows.

(Second embodiment)

10 is an exemplary diagram for explaining a method of controlling an instantaneous output of a storage group while maintaining a continuous output of a power storage system according to another embodiment of the present invention.

As shown in FIG. 10, it is possible to secure the output required by the entire power storage system by configuring a dedicated power converter (PCS) suitable for pulse-type output for each storage group of the divided module unit (see FIG. 10). .

In this way, it is not necessary to implement the storage group as a multiple of the number of switching elements in the PCS. After configuring the system in such a way that a power converter (PCS) suitable for pulse charging/discharging is configured for each storage group implemented in multiple numbers and synthesizing individual outputs, when the power converters (PCS) are sequentially operated, each You can grant a break to the storage group.

Also, since it outputs an instantaneous output pulse for each storage group and has a rest period, it has the advantage of using a switching device with a smaller capacity than the PCS used for regular charging/discharging. The power output for each storage group is superimposed on the transformer to produce continuous ESS output.

(Example 3)

11 is an exemplary diagram for explaining a method of controlling an instantaneous output of a storage group while maintaining a continuous output of the power storage system according to another embodiment of the present invention.

As shown in FIG. 11 , it is possible to sequentially select a storage group of grouped module units or arbitrarily select it according to the state of the storage group and connect it to the power converter (PCS).

In this way, a separate switching circuit is configured between the power converter (PCS) and the storage group to control the output of each storage group.

At this time, the switching circuits are selected in order or in consideration of the state of each storage group, the controller (PCS controller) arbitrarily selects a switching element, selects each storage group, and applies a pulse output to the power converter (PCS). The output of each storage group is input to the PCS through the switching circuit and finally performs continuous ESS output.

Here, the switching circuit may be implemented as a power electronic device such as a thyristor, GTO, IGBT, IGCT, or a mechanical switch or a combination thereof capable of applying and blocking instantaneous current.

As described above, the power system control apparatus and method according to the present embodiment include a battery module or cell constituting a power storage system (ESS) (or a power storage device), and a power converter (PCS: Power Conditioning System) The number of switching elements constituting the PCS is configured as an integer multiple, and charging/discharging input/output signals are applied in the form of pulses from the selected battery cells or battery modules according to the switching order of the switching elements of the power converter (PCS). do. At this time, the size of the instantaneous output current is adjusted according to the MVA (Mega Volt Ampere: power supply capacity) size desired by the system (ESS system). In addition, several battery cells or battery modules are sequentially selected or programmed according to the characteristics of the battery, and the current is continuously supplied from each cell or module in the form of a pulse to the power converter (PCS). do.

In the same manner as described above, a sufficient rest period is provided between the instantaneous outputs of each storage group (battery cell or battery module unit group), thereby obtaining a desired output and simultaneously extending the battery life. In addition, as instantaneous output can be 10 times or more of the rated current, output characteristics of 10C-rate or higher can be achieved without worrying about shortening the life of the battery through the combination of a cell or module group composed of multiples of a power converter (PCS) and a switching element. A power storage system with

As described above, the present invention has been described with reference to the embodiment shown in the drawings, but this is merely exemplary, and various modifications and equivalent other embodiments are possible therefrom by those of ordinary skill in the art. will understand the point. Therefore, the technical protection scope of the present invention should be defined by the following claims.

100: control unit
200: storage
210 ~ 260 : save group
212, 222, 232, 242, 252, 262: storage module
300: conversion unit
310: PCS
320: PCS controller
B-BMS: Master BMS
S-BMS, 211, 221, 231, 241, 251, 261: Slave BMS
SW1 ~ SW6 : Switching element

Claims (10)

In the control apparatus of the power storage system comprising a storage unit for storing electrical energy and a conversion unit connected to the power system,
A storage unit including a master BMS (Battery Management System) for controlling the state monitoring and charging/discharging of the battery, and at least one storage group;
A power converter that converts AC power of a power system into DC power or converts DC power of a battery into AC power, a power converter (PCS) including at least one switching element, and a converter including a PCS controller; and
A control unit for instantaneously charging/discharging the storage unit by sequentially outputting control signals according to a preset order to each storage group of the storage unit and the switching element of the power converter according to the output characteristics required by the power system;
The conversion unit comprises a power converter (PCS) for each storage group of the storage unit,
The storage unit is configured to synthesize the individual outputs of the storage group,
The control unit, the control device of the power storage system, characterized in that by sequentially operating the power converters (PCS) configured for each storage group according to a preset order to give a rest period to each storage group.
According to claim 1, wherein the storage group of the storage unit,
The control device of the power storage system, characterized in that configured as a multiple of the number of at least one or more switching elements constituting the power converter.
According to claim 1, wherein each switching element,
The control device of the power storage system, characterized in that the storage unit is configured to correspond to each storage group in a 1:1 correspondence.
According to claim 1, wherein the control unit,
The control device of the power storage system, characterized in that the control so that the charging/discharging of the storage group is performed according to the energization timing of each switching element of the power converter corresponding to each storage group of the storage unit 1:1.
The method of claim 1, wherein the storage group comprises:
a storage module having at least one battery cell (Cell); and
and at least one slave BMS controlling the state monitoring and charging/discharging of the storage module according to the control of the master BMS.
In the control method of the power storage system comprising a storage unit for storing electrical energy and a conversion unit connected to the power system,
calculating, by the control unit, an output range of the power storage system based on at least one of an operation strategy preset by an operator, an operating condition, and a storage state of the storage unit;
determining, by the control unit, an output amount of the power storage system based on the state of the power system and power market information;
selecting, by the control unit, an operation order of each storage group of the storage unit and each switching element of the conversion unit according to the output amount of the power storage system;
transmitting, by the control unit, a control signal to the BMS (Battery Management System) of the storage unit and the PCS controller of the converting unit at the same time;
The power converter of the conversion unit receiving the control signal converts DC power into AC power by on/off control of each switching element according to a preset sequence, and the BMS of the storage unit receiving the control signal receives the control signal controlling on/off of a storage group corresponding to the switching element; and
The conversion unit outputs the converted output to the power system through on/off of each switching element of the power converter paired with each storage group of the storage unit 1:1.
The conversion unit comprises a power converter (PCS) for each storage group of the storage unit,
The storage unit is configured to synthesize the individual outputs of the storage group,
The control method of the power storage system, characterized in that by sequentially operating the power converters (PCS) configured for each storage group according to a preset order to give a rest period to each storage group.
The method of claim 6, wherein in the step of converting DC power into AC power by controlling the switching element on/off,
Power storage system, characterized in that the power converter sequentially controls on/off of the switching elements according to the control of the control unit, and controls so that the on/off periods of each switching element overlap by a preset period of time control method.
The method of claim 6, wherein the storage group of the storage unit,
The control method of the power storage system, characterized in that configured as a multiple of the number of at least one or more switching elements constituting the power converter.
The method of claim 6, wherein in the step of converting DC power into AC power by controlling the switching element on/off,
The control unit controls the charging/discharging of the storage group to be performed according to the on/off timing of each switching element of the power converter corresponding to each storage group of the storage unit 1:1, and each storage group A method of controlling a power storage system, characterized in that the OFF time of the switching element corresponding to each storage group is maintained for a predetermined period of time in order to have a rest period for a predetermined period of time.
7. The method of claim 6,
The storage state of the storage unit is at least one of power amount and operation condition information, the output range of the power storage system is at least one of maximum output and output time information, and the state of the power system is at least one of frequency, variability, and output control signal information. One, the power market information control method of the power storage system, characterized in that it includes at least one of price and volatility information.

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