KR102222560B1 - An 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 an energy storage system that manages power of a direct current (DC) distribution network, wherein the first converter is connected to the DC distribution network and senses a change in voltage of the DC distribution network. , A second converter connected to the DC distribution network, a first load connected to the second converter and whose voltage is controlled by the second converter, a third converter connected to the DC distribution network, and the third converter It is connected, receives power generated from at least one photovoltaic (PV) panel, is connected to the first battery and the first converter, the charging and discharging is controlled by the third converter, charging and discharging by the first converter It includes a controlled second battery.

Description

Energy storage system {AN ENERGY STORAGE SYSTEM}

The present invention relates to an energy storage system capable of efficiently managing power supply and demand conditions.

The Energy Storage System is a system that increases energy efficiency by storing generated power in each connected system including power plants, substations, and transmission lines, and then selectively and efficiently using the power when it is needed.

The energy storage system can reduce the power generation unit cost and reduce the investment and operation costs required for power facility expansion, if the overall load ratio is improved by leveling the electric loads that fluctuate over time and season, thereby lowering electricity bills and saving energy. can do.

These energy storage systems are installed and used in power generation, transmission and distribution, and customers in the power system, and frequency regulation, generator output stabilization using renewable energy, peak shaving, and load leveling. , It is used for functions such as emergency power.

In addition, energy storage systems are largely divided into physical energy storage and chemical energy storage according to the storage method. Physical energy storage includes methods using pumped water power generation, compressed air storage, and flywheel, and chemical energy storage includes methods using lithium-ion batteries, lead acid batteries, and Nas batteries.

Here, with reference to FIG. 1, a conventional energy storage system will be described.

1 is a schematic diagram illustrating a conventional energy storage system.

In a conventional energy storage system, as shown in FIG. 1, power produced by a photovoltaic (PV) panel (PV) is converted through a DC-DC converter 50 to generate a plurality of loads 30, 31, 32, 33. ). In addition, the power generated by the grid 10 is converted through the AC-DC converter 25 and provided to a plurality of loads 30, 31, 32, and 33.

However, because PV panels (PV) generate power based on new and renewable energy (i.e., solar), power supply is unstable, and when emergency generators or UPS (Uninterruptible Power Supply) structures are not in place, solutions to problems in the event of a grid outage. In the absence of this, the need for an improved energy storage system is emerging.

An object of the present invention is to provide an energy storage system capable of supplementing unstable power supply of a PV panel and supplying power uninterruptedly (ie, non-interrupted) when a problem occurs in a DC distribution network or a grid.

In order to achieve the above object, the energy storage system according to an embodiment of the present invention is an energy storage system that manages power of a direct current (DC) distribution network, which is connected to a DC distribution network and changes the voltage of the DC distribution network. A first converter that senses a signal, a second converter connected to the DC distribution network, a first load connected to the second converter and whose voltage is controlled by the second converter, a third converter connected to the DC distribution network, and a third converter Connected to, receiving power produced from at least one photovoltaic (PV) panel, connected to a first battery and a first converter, which charge/discharge is controlled by a third converter, and charge/discharge is controlled by the first converter And a second battery.

It further includes a fourth converter connected to the second battery and an emergency generator connected to the fourth converter, the power is controlled by the fourth converter.

It is connected to the second battery, and further includes a wind power generator for generating power and supplying it to the second battery.

A fifth converter connected to the DC distribution network and a second load connected to the fifth converter and whose voltage is controlled by the fifth converter are further included.

The first converter is driven in a power control mode to control the power of the second battery, the second converter is driven in the CVCF mode to control the voltage of the first load, and the third converter controls the power of the first battery. It is driven in the power control mode to control, the fourth converter is driven in the power control mode to control the power of the emergency generator, and the fifth converter is driven in the CVCF mode to control the voltage of the second load.

The first converter converts the DC voltage provided from the second battery into a DC voltage and provides it to the DC distribution network or converts the DC voltage provided from the DC distribution network to a DC voltage and provides it to the second battery, and the second converter The DC voltage provided from the DC distribution network is converted into a DC voltage and provided to the first load, and the third converter converts the DC voltage provided from the first battery into a DC voltage and supplied to the DC distribution network or provided from the DC distribution network. The received DC voltage is converted into DC voltage and provided to the first battery, the fourth converter converts the AC voltage provided from the emergency generator to the DC voltage and provides it to the second battery, and the fifth converter is provided from the DC distribution network. The DC voltage is converted into an AC voltage and provided to the second load.

When the voltage of the DC distribution network decreases below a preset reference value within a preset time, the first converter is driven in the DC voltage control mode to control the voltage of the DC distribution network, and discharged power by discharging the second battery. Is supplied to the DC distribution network in an uninterrupted state.

In order to achieve the above object, an energy storage system according to another embodiment of the present invention is an energy storage system that manages power of a grid and a DC distribution network connected to the grid. A first converter that controls the prospective voltage, a second converter connected to the DC distribution network, a first load connected to the second converter and whose voltage is controlled by the second converter, a third converter connected to the DC distribution network, A first battery connected to a third converter, receiving power generated from at least one photovoltaic (PV) panel, and controlling charge/discharge by a third converter, a fourth converter and a fourth converter connected to the DC distribution network And a second battery connected to and controlling charging and discharging by a fourth converter.

It further includes a fifth converter connected to the second battery and an emergency generator connected to the fifth converter and controlling power by the fifth converter.

It is connected to the second battery, and further includes a wind power generator for generating power and supplying it to the second battery.

It further includes a sixth converter connected to the DC distribution network and a second load connected to the sixth converter and whose voltage is controlled by the sixth converter.

The first converter is driven in the DC voltage control mode to control the voltage of the DC distribution network, the second converter is driven in the CVCF mode to control the voltage of the first load, and the third converter is the power of the first battery. Is driven in a power control mode to control power, the fourth converter is driven in a power control mode to control power of the second battery, and the fifth converter is driven in a power control mode to control power of the emergency generator, The sixth converter is driven in CVCF mode to control the voltage of the second load.

The first converter converts the AC voltage provided from the grid into a DC voltage and provides it to the DC distribution network, or converts the DC voltage provided from the DC distribution network into an AC voltage and provides it to the system, and the second converter is provided from the DC distribution network. The received DC voltage is converted into a DC voltage and supplied to the first load, and the third converter converts the DC voltage provided from the first battery into a DC voltage and supplied to the DC distribution network or the DC voltage supplied from the DC distribution network. Converts the DC voltage to a first battery, and the fourth converter converts the DC voltage provided from the second battery to a DC voltage and provides it to the DC distribution network or converts the DC voltage provided from the DC distribution network to a DC voltage. Provided to the second battery, the fifth converter converts the AC voltage provided from the emergency generator into a DC voltage and provides it to the second battery, and the sixth converter converts the DC voltage provided from the DC distribution network to the AC voltage to control the voltage. 2 Provide to the load.

When a problem occurs in the system, the driving of the first converter is stopped, the fourth converter is driven in a DC voltage control mode to control the voltage of the DC distribution network, and the discharged power is distributed to DC by discharging the second battery. It is supplied in a non-transmitted state to the prospect.

As described above, according to the present invention, it is possible to supplement the unstable power supply of the PV panel, and to supply power uninterruptedly when a problem occurs in the DC distribution network or the system, and efficient and stable management of the power supply and demand state is possible.

In addition to the above-described effects, specific effects of the present invention will be described together with explanation of specific matters for carrying out the present invention.

1 is a schematic diagram illustrating a conventional energy storage system.
2 is a schematic diagram illustrating an energy storage system according to an embodiment of the present invention.
3 and 4 are schematic diagrams illustrating the power flow of the energy storage system of FIG. 2.
5 is a schematic diagram illustrating an energy storage system according to another embodiment of the present invention.
6 and 7 are schematic diagrams illustrating the power flow of the energy storage system of FIG. 5.

The above-described objects, features, and advantages will be described later in detail with reference to the accompanying drawings, and accordingly, a person of ordinary skill in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description will be omitted. 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 indicate the same or similar elements.

Hereinafter, an energy storage system according to an embodiment of the present invention will be described with reference to FIGS. 2 to 4.

2 is a schematic diagram illustrating an energy storage system according to an embodiment of the present invention. 3 and 4 are schematic diagrams illustrating the power flow of the energy storage system of FIG. 2.

First, referring to FIG. 2, the energy storage system 1 according to an embodiment of the present invention may manage power of a DC distribution network 20 (ie, a DC system).

Specifically, the energy storage system 1 according to an embodiment of the present invention includes a first converter 100, a second converter 150, a third converter 200, a fourth converter 250, and a fifth converter ( 270), a first battery 300, a second battery 350, a third battery 400, a first load 450, a second load 455, an emergency generator 500, a wind generator 600 Can include.

In addition, the energy storage system 1 may further include at least one PV panel (eg, PV1 to PV7) as well as the DC distribution network 20, and the first load 450 and the second load 455 ), the number of the second converter 150, the fifth converter 270, the PV panels (PV1 to PV7), etc. may be varied, and only one of the first battery 300 and the second battery 350 may be included. have.

Here, the loads 450 and 455 may include, for example, a home, a large building, or a factory. In addition, PV panels (for example, PV1 to PV7) are systems that generate power using solar energy, and the wind power generator 600 may be a system that generates power using wind power.

However, for convenience of explanation, in an embodiment of the present invention, the energy storage system 1 is the first converter 100, the second converter 150, the third converter 200, and the fourth converter 250. , Fifth converter 270, first battery 300, second battery 350, third battery 400, first load 450, second load 455, emergency generator 500, wind power Including the generator 600, the first PV panel group (PVG1) includes four PV panels (PV1 to PV4), and the second PV panel group (PVG2) includes three PV panels (PV5 to PV7) And, the first load 450 includes four loads (451 to 454; load 1-1 to load 1-4), and the second converter 150 also includes four converters (151 to 154). It will be described with an example of what to do.

The first converter 100 is connected to the DC distribution network 20 and may sense a voltage change of the DC distribution network 20.

Specifically, the first converter 100 is connected between the DC distribution network 20 and the third battery 400, detects a voltage change of the DC distribution network 20, and charges and discharges the third battery 400 Can be controlled.

In addition, the first converter 100 converts the DC voltage provided from the third battery 400 into a DC voltage and provides it to the DC distribution network 20 or converts the DC voltage provided from the DC distribution network 20 to a DC voltage. Thus, it may be provided to the third battery 400.

Accordingly, the first converter 100 may be a DC-DC converter.

Here, the meaning of converting the DC voltage to the DC voltage may mean boosting or reducing the DC voltage to a DC voltage of a different level.

In addition, when the voltage (ie, power state) of the DC distribution network 20 is normal, the first converter 100 may be driven in a power control mode to control power of the third battery 400.

Specifically, when the voltage of the DC distribution network 20 is in a normal state, the first converter 100 is configured to perform the SOC (State of Charge) of the third battery 400, the power state of the DC distribution network 20, and the first And charging and discharging the third battery 400 based on the amount of power consumed by the second loads 450 and 455. That is, the first converter 100 discharges the third battery 400 during the maximum load time (when the power consumption of the load is the maximum), and the minimum load time (when the power consumption of the load is the minimum). The peak reduction function may be performed by charging the third battery 400.

On the other hand, when a problem occurs in the voltage of the DC distribution network 20 (for example, the voltage decreases below a preset reference value within a preset time; 20) voltage can be controlled.

Specifically, the first converter 100 can determine whether a problem has occurred in the voltage of the DC distribution network 20 by detecting the voltage change rate of the DC distribution network 20 (that is, the rate of change of the DC voltage over time). have.

In addition, the first converter 100 may control the voltage of the DC distribution network 20 based on the detection result of the voltage change of the DC distribution network 20.

That is, when a problem occurs in the voltage of the DC distribution network 20, the first converter 100 controls the voltage of the DC distribution network 20, without delay (that is, in a non-transitional state), the third battery ( Power of 400) may be supplied to the first and second loads 450 and 455.

The second converter 150 is connected to the DC distribution network 20 and may control the voltage of the first load 450.

Specifically, the second converter 150 may convert the DC voltage provided from the DC distribution network 20 into a DC voltage and provide it to the first load 450. Also, the second converter 150 may be driven in a CVCF mode to control the voltage of the first load 450.

Accordingly, the second converter 150 may be a DC-DC converter, and the first load 450 may be a DC load.

In addition, as shown in FIG. 2, the second converter 150 may be provided with a plurality (eg, 4; 151 to 154) according to the number (eg, 4) of the first load 450. I can.

The third converter 200 is connected to the DC distribution network 20 and may control charging and discharging of the first battery 300 and the second battery 350.

Specifically, the third converter 200 is connected between the DC distribution network 20 and the first and second batteries 300 and 350, and controls charging and discharging of the first and second batteries 300 and 350. I can.

In addition, the third converter 200 converts the DC voltage provided from at least one of the first and second batteries 300 and 350 into a DC voltage and provides it to the DC distribution network 20 or provided from the DC distribution network 20. The received DC voltage may be converted into a DC voltage and provided to at least one of the first and second batteries 300 and 350.

Accordingly, the third converter 200 may be a DC-DC converter.

In addition, the third converter 200 may be driven in a power control mode to control power of the first and second batteries 300 and 350.

Specifically, the third converter 200 is based on the SOC of the first battery 300, the power state of the DC distribution network 20, the power consumption of the first and second loads 450, 455, etc. It is possible to perform charging and discharging of 300, and based on the SOC of the second battery 350, the power state of the DC distribution network 20, the power consumption of the first and second loads 450, 455, etc. 2 Charging and discharging of the battery 350 may be performed. That is, the third converter 200 discharges at least one of the first and second batteries 300 and 350 during the maximum load time (when the power consumption of the load is the maximum), and the minimum load time (load When the power consumption of is the minimum), the peak reduction function may be performed by charging at least one of the first and second batteries 300 and 350.

For reference, the third converter 200 plays a role of controlling the voltage of the DC distribution network 20 in place of the above-described first converter 100 or the DC distribution network 20 together with the first converter 100. Although it may play a role of controlling the voltage of, in the embodiment of the present invention, for convenience of description, for the sake of convenience, the first converter 100 serves to control the voltage of the DC distribution network 20 as an example. I will explain.

The fourth converter 250 may be connected between the third battery 400 and the emergency generator 500 and may control power of the emergency generator 500.

Specifically, the fourth converter 250 may convert the AC voltage provided from the emergency generator 500 into a DC voltage and provide it to the third battery 400. In addition, the fourth converter 250 may be driven in a power control mode to control power of the emergency generator 500.

Accordingly, the fourth converter 250 may be an AC-DC converter.

The fifth converter 270 is connected to the DC distribution network 20 and may control the voltage of the second load 455.

Specifically, the fifth converter 270 may convert the DC voltage provided from the DC distribution network 20 into an AC voltage and provide it to the second load 455. Also, the fifth converter 270 may be driven in a CVCF mode to control the voltage of the second load 455.

Accordingly, the fifth converter 270 may be a DC-AC converter, and the second load 455 may be an AC load.

In addition, a plurality of fifth converters 270 may be provided according to the number of second loads 455.

The first battery 300 is connected to the third converter 200 and receives power generated from at least one PV panel (PV1 to PV4; first PV panel group (PVG1)), and the third converter 200 Charging and discharging can be controlled by.

In addition, the first battery 300 may include at least one battery cell, and each battery cell may include a plurality of bare cells.

For reference, the first battery 300 may receive power from the DC distribution network 20 through the third converter 200.

The second battery 350 is connected to the third converter 200 and receives power generated from at least one PV panel (PV5 to PV7; second PV panel group (PVG2)), and the third converter 200 Charging and discharging can be controlled by.

In addition, the second battery 350 may include at least one battery cell, and each battery cell may include a plurality of bare cells.

For reference, the second battery 350 may receive power from the DC distribution network 20 through the third converter 200.

The third battery 400 is connected to the first converter 100, receives power from the emergency generator 500 and the wind generator 600, and charging and discharging may be controlled by the first converter 100.

In addition, the third battery 400 may include at least one battery cell, and each battery cell may include a plurality of bare cells.

For reference, the third battery 400 may receive power from the DC distribution network 20 through the first converter 100.

The first load 450 is connected to the second converter 150, and a voltage (ie, power) may be controlled by the second converter 150.

In addition, the first load 450 may be, for example, a plurality of (451 to 454; 1-1 load to 1-4 load), and may be an AC load.

The second load 455 is connected to the fifth converter 270, and a voltage (ie, power) may be controlled by the fifth converter 270.

In addition, the second load 455 may be, for example, a plurality, and may be a DC load.

The emergency generator 500 is connected to the fourth converter 250, and power may be controlled by the fourth converter 250.

Specifically, the emergency generator 500 may include, for example, a diesel generator. In addition, the emergency generator 500 may supply power to the third battery 400 when a problem occurs in the DC distribution network 20 (for example, when the voltage of the DC distribution network 20 decreases rapidly). That is, the emergency generator 500 may supply power to the third battery 400 through the fourth converter 250.

The wind power generator 600 is connected to the third battery 400 and may generate power and supply it to the third battery 400.

Specifically, the wind power generator 600 may generate power using wind power (ie, wind), and may supply the generated power to the third battery 400.

Power supplied from the wind generator 600 to the third battery 400 may be, for example, DC power. If the power supplied from the wind generator 600 to the third battery 400 is AC power, the wind generator 600 may also supply power to the third battery 400 through the fourth converter 250.

For reference, although not shown in the drawings, the energy storage system 1 according to an embodiment of the present invention may further include a communication unit (not shown) and a host controller (not shown).

The communication unit includes SOC (State of Charge) information of the third battery 400 from the first converter 100 or voltage change rate information of the DC distribution network 20, and the consumption of the first load 450 from the second converter 150 Power information, SOC (State of Charge) information of the first and second batteries 300 and 350 from the third converter 200, driving information of the emergency generator 500 from the fourth converter 250, the fifth converter ( Power consumption information of the second load 455 and the like may be received from 270.

In addition, the communication unit receives information from the first to fifth converters 100, 150, 200, 250, and 270 according to the situation, and the upper controller (not shown) and the first to fifth converters 100, 150, 200, 250 , 270).

This communication unit may be implemented on a high-speed communication basis (for example, a controller area network (CAN)), and the first to fifth converters 100, 150, 200, 250, 270 and the host controller are wired or wirelessly Can communicate.

Of course, the energy storage system 1 according to an embodiment of the present invention may not include a communication unit. That is, the first to fifth converters 100, 150, 200, 250, 270 and the host controller may directly communicate with each other without a separate communication unit.

In addition, the host controller may be, for example, a PLC (Programmable Logic Controller) or EMS (Energy Management System), and it controls all sequence operations of the energy storage system 1 and commands each component according to each situation. You can also have them perform an action.

Next, referring to FIG. 3, a power flow in the energy storage system 1 when the voltage of the DC distribution network 20 is in a normal state will be described as follows.

Specifically, power produced by the first PV panel group PVG1 is provided to the first battery 300, the first battery 300 is discharged by the third converter 200, and the first battery 300 The power discharged from is transferred to the DC distribution network 20 through the third converter 200, and the power transferred to the DC distribution network 20 is transferred to the first and fifth converters 150 and 270 through the second and fifth converters 150 and 270. It may be provided as the second load (450, 455).

In addition, power produced by the second PV panel group (PVG2) is provided to the second battery 350, and the second battery 350 is discharged by the third converter 200, and discharged from the second battery 350. The converted power is transferred to the DC distribution network 20 through the third converter 200, and the power transferred to the DC distribution network 20 is transferred to the first and second converters 150 and 270 through the second and fifth converters 150 and 270. It may be provided as a load (450, 455).

In addition, the power produced by the wind generator 600 is provided to the third battery 400, the third battery 400 is discharged by the first converter 100, and the power discharged from the third battery 400 is Power transmitted to the DC distribution network 20 through the first converter 100 and transferred to the DC distribution network 20 is transferred to the first and second loads 450 through the second and fifth converters 150 and 270. , 455).

For reference, the power delivered to the DC distribution network 20 through the third converter 200 may be transferred to the third battery 400 or transferred to the DC distribution network 20 through the first converter 100 The generated power may be delivered to at least one of the first and second batteries 300 and 350.

On the other hand, referring to FIG. 4, when a problem occurs in the voltage of the DC distribution network 20, the power flow in the energy storage system 1 will be described as follows.

Specifically, when a problem occurs in the voltage of the DC distribution network 20 (for example, when the voltage of the DC distribution network 20 decreases sharply), the first converter 100 is the voltage of the DC distribution network 20 By detecting the change, the third battery 400 may be discharged without delay (ie, in a non-junction state).

Accordingly, the power discharged from the third battery 400 may be transferred to the DC distribution network 20 through the first converter 100. In this case, the fourth converter 250 is provided with information on the voltage change of the DC distribution network 20 from a host controller (not shown) or a communication unit (not shown), and the emergency generator 500 based on the received information. Can be driven.

Through this, the emergency generator 500 can provide power to the third battery 400 through the fourth converter 250, and the third battery 400 is more based on the power provided from the emergency generator 500. Power can be stably supplied to the DC distribution network 20 for a long time.

Of course, although not shown in the drawing, the third converter 200 is also provided with information on the voltage change of the DC distribution network 20 from a host controller (not shown) or a communication unit (not shown), and based on the received information. At least one of the first and second batteries 300 and 350 may be discharged.

As described above, according to the energy storage system 1 according to an embodiment of the present invention, unstable power supply of the PV panels PV1 to PV7 is supplemented, and when a problem occurs in the DC distribution network 20, power is uninterrupted. As it can supply, efficient and stable management of the power supply and demand status is possible.

Hereinafter, an energy storage system 2 according to another embodiment of the present invention will be described with reference to FIGS. 5 to 7.

5 is a schematic diagram illustrating an energy storage system according to another embodiment of the present invention. 6 and 7 are schematic diagrams illustrating the power flow of the energy storage system of FIG. 5.

For reference, the energy storage system 2 according to another embodiment of the present invention is the same as the above-described energy storage system 1 except for some configurations and effects, and the differences will be mainly described.

First, referring to FIG. 5, the energy storage system 2 includes a first converter 100, a second converter 150, a third converter 200, a fourth converter 250, and a fifth converter 270, Sixth converter 290, first battery 300, second battery 350, third battery 400, first load 450, second load 455, emergency generator 500, wind power generator It may include 600.

In addition, the energy storage system 2 may further include a system 10, and the system 10 may include, for example, a power plant, a substation, a transmission line, and the like.

However, for convenience of explanation, in another embodiment of the present invention, the energy storage system 2 includes the first converter 100, the second converter 150, the third converter 200, and the fourth converter 250. , The fifth converter 270, the sixth converter 290, the first battery 300, the second battery 350, the third battery 400, the first load 450, the second load 455, The emergency generator 500 and the wind power generator 600 are included, and the first load 450 includes three loads 451 to 453 (1-1 loads to 1-3 loads), and a second converter ( 150) will also be described as an example including three converters 151 to 153.

That is, the energy storage system 2 may further include a sixth converter 290 connected to the system 10 than the energy storage system 1 described above.

Specifically, the sixth converter 290 may be connected between the grid 10 and the DC distribution network 20 to control the voltage of the DC distribution network 20.

Specifically, the sixth converter 290 converts the AC voltage provided from the system 10 into a DC voltage and provides it to the DC distribution network 20 or converts the DC voltage provided from the DC distribution network 20 to an AC voltage. Thus, it can be provided to the system 10.

Accordingly, the sixth converter 290 may be an AC-DC converter.

In addition, the sixth converter 290 may be driven in a DC voltage control mode to control the voltage of the DC distribution network 20 when the system 10 is in normal operation.

However, when an accident occurs in the system 10 (that is, when the system 10 is powered off or disconnected), the sixth converter 290 may stop driving by turning off the gate signal. . In addition, the sixth converter 290 may detect the occurrence of an accident in the system 10 and provide a detection result to the first converter 100, a communication unit (not shown), or a host controller (not shown).

For reference, the system 10 is connected to the DC distribution network 20 through the sixth converter 290, the first converter 100 is the SOC of the third battery 400, the power of the DC distribution network 20 Charging and discharging of the third battery 400 may be performed based on the state, the amount of power consumed by the first and second loads 450 and 455, the power supply and demand situation of the system 10, and the like.

In addition, when an accident occurs in the system 10, the sixth converter 290 is stopped, and the first converter 100 may control the voltage of the DC distribution network 20 as described above. .

Specifically, when an accident occurs in the system 10, the first converter 100 receives a system accident detection result from the sixth converter 290 (which may be provided from a communication unit or a host controller) or the DC distribution network 20 By detecting the rate of change of the voltage (ie, the rate of change of the DC voltage over time), it is possible to determine whether an accident has occurred in the system 10.

On the other hand, since the system 10 is connected to the DC distribution network 20 through the sixth converter 290, the third converter 200 is also the SOC of the first battery 300 and the power state of the DC distribution network 20. , Charging and discharging of the first battery 300 may be performed based on the power supply and demand status of the system 10, the amount of power consumed by the first and second loads 450 and 455, and the like, and Charging and discharging the second battery 350 based on the SOC, the power status of the DC distribution network 20, the power supply and demand status of the system 10, the power consumption of the first and second loads 450 and 455, etc. can do.

Next, referring to FIG. 6, the power flow in the energy storage system 2 when the system 10 is operating normally will be described as follows.

Specifically, the system 10 provides power to the sixth converter 290, and the sixth converter 290 converts the power provided from the system 10 and transfers it to the DC distribution network 20. The power delivered to the view 20 may be provided to the first and second loads 450 and 455 through the second and fifth converters 150 and 270.

In addition, power produced by the first PV panel group (PVG1) is provided to the first battery 300, and the first battery 300 is discharged by the third converter 200, and discharged from the first battery 300. The converted power is transferred to the DC distribution network 20 through the third converter 200, and the power transferred to the DC distribution network 20 is transferred to the first and second converters 150 and 270 through the second and fifth converters 150 and 270. It may be provided as a load (450, 455).

In addition, power produced by the second PV panel group (PVG2) is provided to the second battery 350, and the second battery 350 is discharged by the third converter 200, and discharged from the second battery 350. The converted power is transferred to the DC distribution network 20 through the third converter 200, and the power transferred to the DC distribution network 20 is transferred to the first and second converters 150 and 270 through the second and fifth converters 150 and 270. It may be provided as loads 450 and 455.

In addition, the power produced by the wind generator 600 is provided to the third battery 400, the third battery 400 is discharged by the first converter 100, and the power discharged from the third battery 400 is Power transmitted to the DC distribution network 20 through the first converter 100 and transferred to the DC distribution network 20 is transferred to the first and second loads 450 through the second and fifth converters 150 and 270. , 455).

For reference, the power delivered to the DC distribution network 20 through the third converter 200 may be transferred to the third battery 400 or the system 10, or the DC distribution network through the first converter 100 The power delivered to 20 may be delivered to at least one of the first and second batteries 300 and 350 or to the system 10.

On the other hand, referring to FIG. 7, when a problem occurs in the system 10, the power flow in the energy storage system 2 will be described as follows.

Specifically, when a problem occurs in the system 10 (for example, when the system 10 is powered off), the sixth converter 290 is stopped, and the first converter 100 is a sixth converter 290; Alternatively, the third battery 400 can be discharged without delay (i.e., in an uninterrupted state) based on the system accident detection result provided from the system accident detection result or the detected voltage change of the DC distribution network 20. I can.

Accordingly, the power discharged from the third battery 400 may be transferred to the DC distribution network 20 through the first converter 100. In this case, the fourth converter 250 may receive a system accident detection result from a host controller (not shown) or a communication unit (not shown), and may drive the emergency generator 500 based on the received information.

Through this, the emergency generator 500 can provide power to the third battery 400 through the fourth converter 250, and the third battery 400 is more based on the power provided from the emergency generator 500. Power can be stably supplied to the DC distribution network 20 for a long time.

Of course, although not shown in the drawing, the third converter 200 is also provided with a system accident detection result from a host controller (not shown) or a communication unit (not shown), and based on the received information, the first and second batteries 300 , 350) can be discharged.

As described above, according to the energy storage system 2 according to another embodiment of the present invention, it is possible to supplement the unstable power supply of the PV panels (PV1 to PV7) and to supply power uninterruptedly when a problem occurs in the system 10. As possible, efficient and stable management of the power supply and demand status is possible.

The above-described present invention is capable of various substitutions, modifications, and changes within the scope of the technical spirit of the present invention to those of ordinary skill in the technical field to which the present invention pertains. Is not limited by.

100: first converter 150: second converter
200: third converter 250: fourth converter
270: fifth converter 300: first battery
350: second battery 400: third battery
450: first load 455: second load
500: emergency generator 600: wind generator

Claims (14)

In an energy storage system that manages power of a DC (Direct Current) distribution network,
A first converter connected to the DC distribution network and sensing a voltage change of the DC distribution network;
A second converter connected to the DC distribution network;
A first load connected to the second converter and whose voltage is controlled by the second converter;
A third converter connected to the DC distribution network;
A first battery connected to the third converter, receiving power generated from at least one photovoltaic (PV) panel, and controlling charging and discharging by the third converter; And
A third battery connected to the first converter and controlling charging and discharging by the first converter,
The first converter is driven in a power control mode to control power of the third battery,
The second converter is driven in a constant voltage constant frequency (CVCF) mode to control the voltage of the first load,
The third converter is driven in a power control mode to control power of the first battery.
Energy storage system.
The method of claim 1,
A fourth converter connected to the third battery; And
An emergency generator connected to the fourth converter and controlling power by the fourth converter.
Energy storage system.
The method of claim 2,
Further comprising a wind power generator connected to the third battery and supplying power to the third battery by generating power.
Energy storage system.
The method of claim 2,
A fifth converter connected to the DC distribution network; And
Further comprising a second load connected to the fifth converter and whose voltage is controlled by the fifth converter.
Energy storage system.
The method of claim 4,
The fourth converter is driven in a power control mode to control power of the emergency generator,
The fifth converter is driven in a constant voltage constant frequency (CVCF) mode to control the voltage of the second load.
Energy storage system.
The method of claim 4,
The first converter converts the DC voltage provided from the third battery into a DC voltage and provides it to the DC distribution network or converts the DC voltage provided from the DC distribution network to a DC voltage and provides it to the third battery,
The second converter converts the DC voltage provided from the DC distribution network into a DC voltage and provides it to the first load,
The third converter converts the DC voltage provided from the first battery to a DC voltage and provides it to the DC distribution network or converts the DC voltage provided from the DC distribution network to a DC voltage and provides it to the first battery,
The fourth converter converts the AC voltage provided from the emergency generator into a DC voltage and provides it to the third battery,
The fifth converter converts the DC voltage provided from the DC distribution network into an AC voltage and provides it to the second load.
Energy storage system.
The method of claim 1,
When the voltage of the DC distribution network decreases below a preset reference value within a preset time,
The first converter is driven in a DC voltage control mode to control the voltage of the DC distribution network, and discharges the third battery to supply the discharged power to the DC distribution network in an uninterrupted state.
Energy storage system.
In the energy storage system for managing power of a grid and a DC distribution network connected to the grid,
A sixth converter connected between the system and the DC distribution network to control a voltage of the DC distribution network;
A second converter connected to the DC distribution network;
A first load connected to the second converter and whose voltage is controlled by the second converter;
A third converter connected to the DC distribution network;
A first battery connected to the third converter, receiving power generated from at least one photovoltaic (PV) panel, and controlling charging and discharging by the third converter;
A first converter connected to the DC distribution network; And
A third battery connected to the first converter and controlling charging and discharging by the first converter,
The sixth converter is driven in a DC voltage control mode to control the voltage of the DC distribution network,
The second converter is driven in a constant voltage constant frequency (CVCF) mode to control the voltage of the first load,
The third converter is driven in a power control mode to control power of the first battery,
The first converter is driven in a power control mode to control power of the third battery.
Energy storage system.
The method of claim 8,
A fourth converter connected to the third battery; And
An emergency generator connected to the fourth converter and controlling power by the fourth converter.
Energy storage system.
The method of claim 9,
Further comprising a wind power generator connected to the third battery and supplying power to the third battery by generating power.
Energy storage system.
The method of claim 9,
A fifth converter connected to the DC distribution network; And
Further comprising a second load connected to the fifth converter and whose voltage is controlled by the fifth converter.
Energy storage system.
The method of claim 11,
The fourth converter is driven in a power control mode to control power of the emergency generator,
The fifth converter is driven in a constant voltage constant frequency (CVCF) mode to control the voltage of the second load.
Energy storage system.
The method of claim 11,
The sixth converter converts the AC voltage provided from the system into a DC voltage and provides it to the DC distribution network or converts the DC voltage provided from the DC distribution network into an AC voltage and provides it to the system,
The second converter converts the DC voltage provided from the DC distribution network into a DC voltage and provides it to the first load,
The third converter converts the DC voltage provided from the first battery to a DC voltage and provides it to the DC distribution network or converts the DC voltage provided from the DC distribution network to a DC voltage and provides it to the first battery,
The first converter converts the DC voltage provided from the third battery into a DC voltage and provides it to the DC distribution network or converts the DC voltage provided from the DC distribution network to a DC voltage and provides it to the third battery,
The fourth converter converts the AC voltage provided from the emergency generator into a DC voltage and provides it to the third battery,
The fifth converter converts the DC voltage provided from the DC distribution network into an AC voltage and provides it to the second load.
Energy storage system.
The method of claim 8,
If there is a problem with the above system,
The sixth converter is stopped driving,
The first converter is driven in a DC voltage control mode to control the voltage of the DC distribution network, and discharges the third battery to supply the discharged power to the DC distribution network in an uninterrupted state.
Energy storage system.

Images