KR102196639B1 - Energy storage device using lithium battery and supercapacitor and method of output stabilizing thereof - Google Patents

Abstract

The energy storage system using a lithium-ion battery and a supercapacitor charges and converts DC power by rectifying AC generated from a renewable energy generation facility and commercial power (AC) of the system with a rectifier to a power storage device (PSS). , Receives a command from the DSP controller, converts the charging power of the PSS into AC power and discharges it to the load, and regulates the charging and discharging of the PSS through communication control with a battery management system (BMS) that monitors and protects the PSS. A two-way power conversion device (Bi-dPCS, 200); A battery management device (BMS, 300) serving as a protection for maintaining a balance of each PSS cell through communication control with the Bi-dPCS and stopping charging when an input voltage falls below a predetermined value; A number of lithium-ion batteries 410 and supercapacitors 420 that charge DC power of the commercial power rectified with the new and renewable energy generation facility by the Bi-dPCS and BMS are connected in series and in parallel to correspond to the system load. A power storage device (PSS, 400) having one pack; It includes a DSP controller 600 for controlling the Bi-dPCS that regulates charging/discharging and bi-directional power conversion of the PSS by sensing the system load, and the DSP controller is a sensor connected to the system to detect load-side information. The supercapacitor is charged through the Bi-dPCS when an abnormal voltage is generated by monitoring the state of the rectifier of the Bi-dPCS by receiving information from.

Description

TECHNICAL FIELD The energy storage device using lithium battery and supercapacitor and method of output stabilizing thereof

The present invention relates to an energy storage system, and more particularly, an energy storage system using a lithium-ion battery and a supercapacitor capable of adaptively responding to a general load (normal load) and a rapid load (starting load), and output thereof It relates to the stabilization method.

Lithium battery-based energy storage systems have high energy density and energy efficiency, and are being applied to energy storage devices such as new and renewable energy linkage, frequency control, and PV linkage.

The battery-based energy storage system has safety, life, and slow response to load fluctuations, and can be implemented as a hybrid energy storage system (HESS) used with a supercapacitor to compensate for slow response to load fluctuations. Here, the supercapacitor is capable of rapid charging and discharging, has high charging and discharging efficiency, and has semi-permanent cycle life characteristics.

Korean Patent No. 1,863,138 (registered on May 25, 2018) "Power-controlled energy storage device using lithium-ion battery and super capacitor"

The energy storage system consists of a bi-directional DC-DC converter, a supercapacitor, and a lithium-ion battery, and when a load fluctuation occurs during power control based on a lithium-ion battery, an abnormal voltage is caused to the DC-capacitor (for example, a rectifier). And, such a phenomenon not only puts a strain on the DC-capacitor, but also degrades the power quality and reliability of the energy storage system.

The technical problem to be solved is to provide an energy storage system capable of stabilizing the output of a DC-capacitor and a method for stabilizing the output thereof by storing energy through the buck operation of a supercapacitor for an abnormal voltage caused by a change in a load. .

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In order to achieve one object of the present invention, the energy storage system according to embodiments of the present invention, DC power rectified by a rectifier AC and commercial power (AC) of the system generated in the renewable energy generation facility A battery management system (BMS) that charges and converts power to a power storage device (PSS), but converts the charging power of the PSS into AC power and discharges it to a load by receiving a command from the DSP controller, and monitors and protects the PSS. A two-way power conversion device (Bi-dPCS, 200) that regulates charging and discharging of the PSS through communication control of the PSS; A battery management device (BMS, 300) serving as a protection for maintaining a balance of each PSS cell through communication control with the Bi-dPCS and stopping charging when an input voltage falls below a predetermined value; A number of lithium-ion batteries 410 and supercapacitors 420 that charge DC power of the commercial power rectified with the new and renewable energy generation facility by the Bi-dPCS and BMS are connected in series and in parallel to correspond to the system load. A power storage device (PSS) 400 having one pack; It includes a DSP controller 600 for controlling the Bi-dPCS for controlling the charging/discharging and bidirectional power conversion of the PSS by sensing the system load. Here, the DSP controller receives information from a sensor connected to the system and senses load-side information, monitors the state of the rectifier of the Bi-dPCS, and charges the supercapacitor through the Bi-dPCS when an abnormal voltage occurs. have.
According to one embodiment, the Bi-dPCS is. A battery converter 210 connected between the DC-capacitor and the lithium-ion battery to regulate charge/discharge of the lithium-ion battery; And a supercapacitor converter 220 connected between the DC-capacitor and the supercapacitor to regulate charging and discharging of the supercapacitor. Here, the DSP controller may calculate a power error between the reference power Pref and the actual power Pload, and buck the supercapacitor converter 220 in response to the power error.

According to an embodiment, the DSP controller is configured to charge the supercapacitor with a voltage in response to the power error when an overpower having the actual power Pload greater than the reference power Pref is detected. The converter 220 is controlled, and when the actual power Pload is less than the reference power Pref, the battery converter 210 is controlled to maintain the actual power Pload by compensating for the power error. I can.

In order to achieve one object of the present invention, a method for stabilizing the output of an energy storage system according to embodiments of the present invention includes DC generated by a renewable energy generation facility and a commercial power supply (AC) of the system rectified by a rectifier. A battery management system (BMS) that charges and converts power to a power storage device (PSS), but converts the charging power of the PSS into AC power and discharges it to a load by receiving a command from a DSP controller, and monitors and protects the PSS. A two-way power conversion device (Bi-dPCS, 200) that regulates charging and discharging of the PSS through communication control with the device; A lithium ion battery 410 and a plurality of supercapacitors 420 that charge DC power of the commercial power rectified with the new and renewable energy generation facility by the Bi-dPCS are connected in series and parallel to respond to the system load. A power storage device (PSS) 400 having a pack; It can be performed in an energy storage system including a DSP controller 600 for controlling the Bi-dPCS that regulates the charging/discharging and bidirectional power conversion of the PSS by sensing the system load. The output stabilization method includes: monitoring a state of the rectifier of the Bi-dPCS through the DSP controller that is connected to the system and receives information from a sensor that senses load-side information; Comparing the actual power (Pload) in the rectifier with the reference power (Pref) through the DSP controller; And in response to a power error between the actual power Pload and the reference power Pref, when overpower is detected in which the actual power Pload in the rectifier is greater than the reference power Pref. Bucking the Bi-dPCS.

The energy storage system and its output stabilization method according to the present invention can stabilize the output of the DC-capacitor by monitoring the state of the DC-capacitor in real time and storing energy through the buck operation of the supercapacitor energy storage device when an abnormal voltage occurs. have. Therefore, the reliability and power quality of the energy storage system can be improved.

1 is a block diagram illustrating a power system according to embodiments of the present invention.
2 is a circuit diagram showing an energy storage system included in the power system of FIG. 1.
FIG. 3 is a diagram illustrating a process of controlling an operation of a lithium ion battery included in the energy storage system of FIG. 2.
4 is a diagram illustrating a process of controlling an operation of a supercapacitor included in the energy storage system of FIG. 2.
5 is a flowchart illustrating a method of stabilizing output of an energy storage system according to embodiments of the present invention.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. The present invention may be implemented in various different forms, and is not limited to the embodiments described herein.

In order to clearly describe the present invention, parts irrelevant to the description have been omitted, and the same reference numerals are assigned to the same or similar components throughout the specification. Therefore, the reference numerals described above may also be used in other drawings.

1 is a block diagram illustrating a power system according to embodiments of the present invention.

Referring to Figure 1, the power system (or, an energy storage system using a lithium-ion battery and a supercapacitor) is largely a renewable energy generation facility 100, a bidirectional power conversion device (Bi-d PCS, Bidirectional Power Conditioning System, 200), battery management device (BMS, Battery Management System, 300), power storage device (PSS, Power Storage System, 400), grid-side power conversion device 500 and DSP controller (Digital Signal Processor Controller, 600). I can.

The renewable energy generation facility 100 is a means for generating electric energy using energy of sunlight and wind, and the power produced by the photovoltaic power generation facility is direct current (DC), so it is used as a storage device such as a battery. Although charging is possible, electricity produced by wind power generation facilities is mostly alternating current rather than direct current, so it must be converted to direct current (DC) to charge it with a storage device. In addition, in order to supply the DC stored in the storage device to the other loads excluding the DC load, it must be converted into AC (AC). In contrast to solar power generation, wind power generation is charged with a storage device using a high-performance supercapacitor because the output changes rapidly according to wind speed.

The bi-directional power conversion device (Bi-dPCS, Bidirectional Power Conditioning System, 200), in order to convert the electric energy stored in the power storage device 400 into commercial power, the output of the power storage device ( DC power) is directly converted from the Bi-dPCS to AC or the power of the system (AC) is directly rectified from the Bi-dPCS to DC, and the renewable energy generation facility 100 and the commercial power supply of the system (AC ) Is rectified with a rectifier (or DC-capacitor) and charged with a power storage device (PSS, 400), and the power between DC and AC is converted. At this time, receiving a command from the DSP controller 600 directly converts the charging power of the PSS 400 into AC power and discharges it to the load.

In addition, the bi-directional power conversion device (Bi-dPCS, 200) performs communication control with the battery management system (BMS, 300) that monitors and protects the PSS (400) to provide a state of charge (SOC) provided by the BMS. And the charging and discharging of the lithium ion battery 410 and the supercapacitor 420 of the PSS are regulated using the voltage information.

In embodiments, the bi-directional power conversion device (Bi-dPCS, 200), the AC power supplied from the system (for example, commercial power), the lithium ion battery 410 of the PSS (400) and a supercapacitor ( It may include a rectifier (or DC-capacitor) for directly converting into DC power for charging with 420).

The bi-directional power conversion device (Bi-dPCS, 200) is for directly converting into AC power to supply DC power discharged from the lithium ion battery 410 and the supercapacitor 420 of the PSS 400 to a load. A three-level inverter (3-Level Inverter) is provided and can be built into the bi-directional power conversion device (Bi-dPCS, 200).

For reference, in the bidirectional power conversion device (BidPCS, 200), the power produced from the renewable energy generation facility 100 such as solar power generation or wind power generation is in the form of direct current. When this power is stored in the lithium ion battery 410 or the supercapacitor 420 of the power storage device (PSS, 400), it must be stored in direct current, but the problem is that supplying direct current type power to the system load in that state impossible. Therefore, in order to convert direct current (DC) type power into alternating current (AC) power, a power converter (PCS) is required. In addition, when the system power (commercial power) is stored in a power storage device (PSS, 400), a power conversion device (PCS) or a rectifier that converts power to DC power is required.

In this way, when the renewable energy generation facility 100 and the system (commercial power supply) are connected, a power conversion device capable of converting direct current (DC) into alternating current (AC) and alternating current (AC) into direct current (DC) ( PCS) is required, and a bidirectional power conversion device (Bi-dPCS, Bi-directional Power Conditioning System, 200) was originally implemented.

Meanwhile, in order to extend the life of the lithium ion battery 410 and supercapacitor 420 of the power storage device (PSS, 400) due to charging and discharging, the state of charge (SOC, State) of the power storage device (PSS, 400) of Charge) is important to keep constant. In addition, if the state of charge (SOC) continues to be too low or high, the deterioration of the lithium ion battery 410 and the supercapacitor 420 of the power storage device (PSS, 400) is faster than when the SOC is maintained at an intermediate level. It proceeds, and the appropriate SOC range can be known through repeated experiments. In addition, if the cells of the lithium-ion battery 410 and the supercapacitor 420 are over-discharged, the component parts are deteriorated and the cells become unrecoverable. In addition, when the charging voltage is also charged beyond the threshold, the cells of the lithium-ion battery 410 and the supercapacitor 420 are overheated to change into an irreversible structure. To overcome this problem, the battery management device (BMS, 300), which will be described later, is shared.

In one embodiment, the bi-directional power conversion device (Bi-dPCS, 200) is a power management system (PMS, Power Management System) or an energy management system (EMS), which is an upper controller of the DSP controller (Digital Signal Processor Controller, 600). , Energy Management System) can be configured to enable bidirectional power conversion control by a selected current command.

In one embodiment, the bidirectional power conversion device (Bi-dPCS, 200) charges DC power in the lithium ion battery 410 and the supercapacitor 420 of the power storage device 400 by performing current control, It can be configured to be supported by a constant power control that receives a current command from a host controller and charges it with constant power, that is, a control method of a power conversion device that constantly preserves DC power.

The battery management device (BMS, Battery Management System, 300) is installed together with the power storage device 400 to charge and discharge through the same terminals (P+ and P-), and through communication control with the Bi-dPCS. As a means for maintaining the balance of each PSS cell and stopping charging when the input voltage falls below a certain value, the lithium ion battery 410 of the power storage device (PSS, 400) and The power storage device is protected by monitoring the state of each cell of the supercapacitor 420 and a protection circuit to protect it, and the power storage device through communication with the Bi-dPCS 200 ( The state and operation information of each cell of the lithium ion battery 410 and the supercapacitor 420 of 400) is transmitted to the PC monitor.

In addition, the battery management device (BMS, 300) is composed of a measurement structure for efficient operation, and a system BMS that monitors and protects the entire power storage device, a storage device module, and an individual storage device cell. It can be composed of a module to protect BMS, etc.

In addition, the battery management device (BMS, 300) communicates (protocol open) with the Bi-dPCS 200 to determine the minimum, average, and maximum voltage and temperature of each cell, the total voltage of the energy storage system, and the operation state. It is configured to collect and calculate information about the state of charge (SOC), and the remaining life (SOH, State of Health), and transmit it to an external device (or PC) through the interface.

That is, the battery management system (BMS, Battery Management System, 300) can be largely divided into two. First, heat management is controlled so that each cell is cooled evenly by heat to realize the same performance, and secondly, the state of charge that determines the state of each cell and operates at the optimum efficiency point ( It can be divided into SOC) control. In these two control modes, the rated voltage of a single cell of a Li-ion battery is 3.6V and the charging voltage is 4.2V, so lithium-ion batteries are connected in series to generate voltages exceeding several hundred volts. . When several cells are connected in series, if any one of them fails or deteriorates, the entire battery pack is affected. Therefore, BMS applied to HEV (Hybrid Electric Vehicle) or EV (Electric Vehicle) prevents overcharging, overdischarging, and overheating of individual cells and optimizes their lifespan so that all cells are always in an equal state of charge. This is because a cell balance that maintains is required. In addition, BMS monitors the voltage, current and temperature of the system and maintains it in an optimal state, and provides alarms and precautionary safety precautions for system stabilization. It protects overcharge and overdischarge during charging and discharging of a battery, and extends energy efficiency and battery life by making the voltage between cells uniform. In addition, by preserving data and diagnosing the system, it is possible to save and diagnose alarm-related history status through diagnosis system or monitoring PC. This BMS function is configured to be applied to both the lithium ion battery 410 and the supercapacitor 420 according to an embodiment of the present invention.

The grid-side power conversion device 500 uses the DC power charged in the lithium ion battery 410 and the supercapacitor 420 of the renewable energy generation facility 100 and the power storage device (PSS, 400) as a load. As a means for converting into AC power to supply, DC power supplied from the renewable energy generation facility 100 is converted into AC power to supply the load to the load.

In addition, the grid-side power conversion device 500 may apply a three-phase 3-level inverter and a PWM (Pulse Width Modulation) control method.

The DSP controller (Digital Signal Processor Controller, 600) is a means for controlling the operation and power conversion of the bi-directional power conversion device (Bi-dPCS, 200), the DSP controller 600 is the system-side power conversion device A two-way power conversion device that receives information from a sensor (IoT) that detects load-side information connected to the 500 and regulates charging and discharging of the power storage device (PSS, 400) and converting bidirectional power between DC and AC. (Bi-dPCS, 200) is controlled.

The DSP controller 600 is a signal for DC power through a DC power supply and a grid (commercial power supply) and a rectifier (or DC-capacitor) of the renewable energy generation facility 100, which is first introduced into the connection panel 110. The bi-directional power conversion device (Bi-dPCS, 200) connected to the connection panel 110 to charge the lithium ion battery 410 and the supercapacitor 420 of the power storage device (PSS, 400) by receiving Gives a control command. At this time, the bi-directional power conversion device (Bi-dPCS, 200) receiving the command from the DSP controller 600 transfers the DC power connected to the connection panel 110 and the DC power passing through the rectifier to the lithium ion battery of the power storage device. Switch and connect to each of the supercapacitors to charge the lithium-ion battery and supercapacitor.

In addition, the DSP controller 600 receives a signal from a sensor (Iot) that detects a normal general load such as a light load connected to the grid-side power conversion device 500 that supplies AC power to the grid load and receives the power. A control command is given to the bi-directional power conversion device (Bi-dPCS, 200) to supply the charged power charged in the lithium ion battery 410 and the supercapacitor 420 of the storage device (PSS, 400) to the load. At this time, when the signal of the sensor Iot connected to the system-side power conversion device 500 is a general load, the bi-directional power conversion device (Bi-dPCS, 200) causes the lithium ion battery of the power storage device (PSS, 400). The DC power charged in 410 is directly converted to AC power through the Bi-dPCS 200 and supplied to a load or the system side power conversion device 500 is controlled to be supplied.

And when the signal of the sensor Iot connected to the system-side power conversion device 500 is a rapid load, the bi-directional power conversion device (Bi-dPCS, 200) causes the supercapacitor of the power storage device (PSS, 400) ( The DC power charged in the 420 is directly converted into AC power and supplied to a load or controlled to be supplied to the system-side power conversion device 500.

In embodiments, the DSP controller 600 monitors the state of the DC-capacitor of the bi-directional power conversion device (Bi-dPCS, 200), and when an abnormal voltage occurs due to a load change, the bi-directional power conversion device (Bi-dPCS) , 200) may be used to charge the supercapacitor 420. For example, when overpower is detected in which the actual power (Pload) of the DC-capacitor is greater than the reference power (Pref) (or, the command power, the target power), the DSP controller 600 performs the actual power (Pload). In response to a power error between) and the reference power Pref, the bidirectional power conversion device (Bi-dPCS, 200) may be controlled to charge a voltage in the supercapacitor 420. Through this, the voltage level of the DC-capacitor can be maintained at a constant level.

2 is a circuit diagram illustrating an energy storage system included in the power system of FIG. 1.

Referring to FIG. 2, the energy storage system includes a DSP controller 600, a power storage device 400 (that is, a lithium ion battery 410 and a supercapacitor 420), and a bi-directional power conversion device (Bi-dPCS, 200). ) Can be included.

The bi-directional power conversion device (Bi-dPCS) 200 may include a battery converter 410 (or a first converter) and a supercapacitor converter 220 (or a second converter). The battery converter 210 may be connected between the DC-capacitor C and the lithium ion battery 410 to regulate charging and discharging of the lithium ion battery 410. Similarly, the supercapacitor converter 220 may be connected between the DC-capacitor (C) and the supercapacitor 420 to regulate charging/discharging of the supercapacitor 420. Each of the battery converter 410 and the supercapacitor converter 220 may be implemented as a half-bridge converter, as shown in FIG. 2.

The DSP controller 600 includes a power command (Pdc_ref) (or command power, reference power, target power) for the lithium-ion battery 410 based on current/voltage information sensed through a plurality of sensors, and a supercapacitor. A current command (Isc_ref) (or a charging command) for 420 may be generated. Here, the current/voltage information includes the battery voltage (Vdc), the battery output current (Idc), the voltage of the DC-capacitor (C) (Vdc) (i.e., the load-side voltage), the supercapacitor voltage (Vsc), and the supercapacitor output current ( Isc) may be included.

In embodiments, the DSP controller 600 may calculate a power error between the reference power Pref and the actual power Pload, and operate the supercapacitor converter 220 buck in response to the power error.

For example, the DSP controller 600, when the actual power (Pload) is greater than the reference power (Pref) is detected, the super capacitor to charge a voltage in response to the power error. The capacitor converter 220 can be controlled. In addition, the DSP controller 600, when the actual power (Pload) is less than the reference power (Pref), compensates for the power error to maintain the actual power (Pload) to be constant. Can be controlled.

3 is a diagram illustrating a process of controlling an operation of a lithium ion battery included in the energy storage system of FIG. 2. 4 is a diagram illustrating a process of controlling an operation of a supercapacitor included in the energy storage system of FIG. 2.

First, referring to FIGS. 2 and 3, the DSP controller 600 calculates a power error by comparing the power information (Pload) of the load side and the power command (Pdc_ref) (or reference power), and calculates a power error as much as the power error. The output of the lithium ion battery 410 may be compensated or controlled through a (proportional integral) controller.

For example, the DSP controller 600 (or the battery controller 610) is based on the voltage (Vdc) and current (Idc) of the lithium-ion battery 410, the supply power (Pdc) (or, the load side Power information (Pload)) is calculated, the power command (Pdc_ref) and the supplied power (Pdc) are differentially calculated to calculate the power error, and the current command (Idc_ref) corresponding to the power error is generated through the PI controller (PI). In addition, the current command (Idc_ref) and the current information (Idc) may be differentially calculated, and a control signal for compensating the power error may be generated through the PI controller. The control signal is provided to the battery converter 410 through pulse width modulation (PWM), and according to the operation of the battery converter 410 in response to the control signal, power at the DC-capacitor terminal may be kept constant.

4, the DSP controller 600 calculates a power error by comparing the command power (Pdc_ref) (or, the reference power, the power command) and the actual power (Pload), and calculates a power error as much as the power error through the current controller. A voltage may be charged in the supercapacitor 420.

For example, the DSP controller 600 (or supercapacitor controller 620) calculates a power error by calculating the actual power (Pload) from the command power (Pdc_ref) (or reference power, power command). It generates a current command (Idc_ref) corresponding to the power error through the PI controller (PI), calculates the difference between the current command (Idc_ref) and the output current (Isc), and compensates the power error through the PI controller. Can be created. The control signal is provided to the supercapacitor converter 220 through pulse width modulation (PWM), and the operation of the supercapacitor converter 220 in response to the control signal (for example, the supercapacitor converter 220 shown in FIG. ) Of the first switch S1), the voltage at the DC-capacitor terminal may be maintained at a predetermined level.

For example, the DSP controller 600, when the actual power (Pload) is greater than the reference power (Pref) is detected, the super capacitor to charge a voltage in response to the power error. The capacitor converter 220 can be controlled. In addition, the DSP controller 600, when the actual power (Pload) is less than the reference power (Pref), compensates for the power error to maintain the actual power (Pload) to be constant. Can be controlled.

As described with reference to FIGS. 3 and 4, the energy storage system according to embodiments of the present invention monitors actual power (Pload) (or the state of the DC-capacitor) in real time, and The output of the DC-capacitor may be stabilized through the buck operation of the supercapacitor 420 for the generated abnormal voltage. In particular, the energy storage system, the supercapacitor converter 220 to charge a voltage in the supercapacitor in response to the power error when an overpower having the actual power Pload greater than the reference power Pref is detected. By controlling the DC-capacitor, the voltage of the DC-capacitor can be maintained at a certain level.

5 is a flowchart illustrating a method of stabilizing output of an energy storage system according to embodiments of the present invention.

1, 2 and 5, the method of FIG. 5 may be performed in the power system of FIG. 1 (or the energy storage system of FIG. 2 ).

The method of FIG. 5 may monitor the state of the DC-capacitor of the Bi-dPCS 200 through the DSP controller 600 (S510). For example, the method of FIG. 5 monitors the voltage fluctuation of the DC-capacitor through current/voltage information received through a separate sensor, and it is possible to check the occurrence of an abnormal voltage caused by the load fluctuation.

In the method of FIG. 5, the actual power Pload of the DC-capacitor may be compared with the reference power Pref through the DSP controller 600 (S520). For example, the method of FIG. 5 may determine whether the actual power Pload is greater than the reference power Pref.

When an overpower in which the actual power Pload in the DC-capacitor is greater than the reference power Pref is detected, the method of FIG. 5 corresponds to a power error between the actual power Pload and the reference power Pref. Thus, the bi-directional power conversion device (Bi-dPCS) 200 (or the supercapacitor converter 220) may be bucked with respect to the supercapacitor 420 (S530).

In contrast, when the actual power Pload is less than the reference power Pref, the method of FIG. 5 controls the battery converter 210 to maintain the actual power Pload by compensating for the power error. It can be done (S540).

Since the process of controlling the battery converter 210 and the supercapacitor converter 220 is substantially the same as that described with reference to FIGS. 2 to 4, duplicate descriptions will not be repeated.

As described with reference to FIG. 5, in the method for stabilizing the output of the energy storage system according to embodiments of the present invention, when an overpower having an actual power Pload greater than the reference power Pref is detected, the power error In response to the control of the supercapacitor converter 220 to charge a voltage to the supercapacitor, and, when the actual power Pload is less than the reference power Pref, the power error is compensated for the actual power ( The battery converter 210 may be controlled so that Pload) is kept constant. Therefore, the voltage of the DC-capacitor can be maintained at a certain level.

The drawings referenced so far and the detailed description of the invention described are merely illustrative of the present invention, which are used only for the purpose of describing the present invention, but are used to limit the meaning or the scope of the invention described in the claims. It is not. Therefore, those of ordinary skill in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

100: Renewable energy generation facility
110: access panel
200: Bi-directional power conversion device (Bi-dPCS)
210: battery converter
220: supercapacitor converter
300: battery management device (BMS)
400: power storage device (PSS)
410: lithium-ion battery
420: supercapacitor
500: grid-side power conversion device
600: DSP controller

Claims (4)

The AC generated in the renewable energy generation facility and the DC power obtained by rectifying the commercial power (AC) of the system with a rectifier are charged and converted into a power storage device (PSS), but the charging power of the PSS is converted by receiving a command from the DSP controller A two-way power conversion device (Bi-dPCS, 200) that regulates charging and discharging of the PSS through communication control with a battery management system (BMS) that converts into AC power and discharges it as a load, and monitors and protects the PSS. ;
A battery management device (BMS, 300) serving as a protection for maintaining a balance of each PSS cell through communication control with the Bi-dPCS and stopping charging when an input voltage falls below a predetermined value;
A number of lithium-ion batteries 410 and supercapacitors 420 that charge DC power of the commercial power rectified with the new and renewable energy generation facility by the Bi-dPCS and BMS are connected in series and in parallel to correspond to the system load. A power storage device (PSS) 400 having one pack;
Including a DSP controller 600 for controlling the Bi-dPCS for controlling the charging/discharging and bidirectional power conversion of the PSS by sensing the system load,
The DSP controller is connected to the system and receives information from a sensor that senses load-side information, monitors the state of the rectifier of the Bi-dPCS, and charges the supercapacitor through the Bi-dPCS when an abnormal voltage occurs. Energy storage system.
The method of claim 1, wherein the Bi-dPCS is.
A battery converter 210 connected between the rectifier and the lithium ion battery to regulate charging and discharging of the lithium ion battery; And
A supercapacitor converter 220 connected between the rectifier and the supercapacitor to regulate charging and discharging of the supercapacitor,
The DSP controller calculates a power error between the reference power Pref and the actual power Pload, and when overpower having the actual power Pload greater than the reference power Pref is detected, And controlling the supercapacitor converter 220 to charge the supercapacitor with a voltage.
The method of claim 2, wherein the DSP controller,
When the actual power Pload is less than the reference power Pref, the battery converter 210 is controlled to maintain the actual power Pload by compensating for the power error.
The AC generated in the renewable energy generation facility and the DC power obtained by rectifying the commercial power (AC) of the system with a rectifier are charged and converted into a power storage device (PSS), but the charging power of the PSS is converted by receiving a command from the DSP controller A two-way power conversion device (Bi-dPCS, 200) that regulates charging and discharging of the PSS through communication control with a battery management system (BMS) that converts into AC power and discharges it as a load, and monitors and protects the PSS. ; A lithium ion battery 410 and a plurality of supercapacitors 420 that charge DC power of the commercial power rectified with the new and renewable energy generation facility by the Bi-dPCS are connected in series and parallel to respond to the system load. A power storage device (PSS) 400 having a pack; In an energy storage system including a DSP controller 600 for controlling the Bi-dPCS that regulates the charging/discharging and bidirectional power conversion of the PSS by detecting the system load,
Monitoring a state of the rectifier of the Bi-dPCS through the DSP controller that is connected to the system and receives information from a sensor that senses load-side information;
Comparing the actual power (Pload) in the rectifier with the reference power (Pref) through the DSP controller; And
When an overpower in which the actual power Pload in the rectifier is greater than the reference power Pref is detected, the Bi for the supercapacitor in response to a power error between the actual power Pload and the reference power Pref A method of stabilizing the output of an energy storage system, comprising buck operating -dPCS.

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