KR20200082293A - Energy storage device using lithium battery and supercapacitor and method of output stabilizing thereof - Google Patents

Abstract

Provided are an energy storage system using a lithium ion battery and a supercapacitor that can adaptively respond to a general load and a rapid load and an output stabilization method thereof. The energy storage system using a lithium battery and a supercapacitor includes: a bi-directional power conversion device (Bi-dPCS, 200) that charges, discharges and converts DC power obtained by rectifying commercial power (AC) of a renewable energy generation facility and a system for a power storage device (PSS), and coverts the charging power of the PSS by receiving a command from a DSP controller to be discharged to a load through a DC capacitor, wherein the Bi-dPCS regulates the charging and discharging of the PSS through communication control with a battery management system (BMS) that monitors and protects the PSS; the BMS (300) that serves as protection for maintaining a balance of each PSS cell through communication control with the Bi-dPCS and stops charging when the input voltage is less than a predetermined value; a power storage device (PSS, 400) having one pack in which a number of lithium ion batteries (410) and supercapacitors (420) that charge and discharge DC power of the rectified commercial power are connected in series and parallel to the renewable energy generation facility by the Bi-dPCS and BMS to correspond to a system load; and 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, wherein the DSP controller monitors the state of the DC-capacitor of the Bi-dPCS and charges the supercapacitor through the Bi-dPCS when an abnormal voltage occurs.

Description

Energy storage system using lithium ion battery and supercapacitor and its output stabilization method{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 specifically, 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 (start load) and an output thereof. It relates to a 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 renewable energy linkage, frequency adjustment, and PV linkage.

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

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

The energy storage system is composed of a bi-directional DC-DC converter, a supercapacitor, and a lithium ion battery. When a load fluctuation occurs during power control based on a lithium ion battery, an abnormal voltage is generated in a DC-capacitor (for example, a rectifier). This phenomenon not only overloads 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 and a method for stabilizing the output of the DC-capacitor by stabilizing the output of the DC-capacitor by storing energy through the buck operation of the supercapacitor to generate an abnormal voltage caused by fluctuation of load .

In order to achieve one object of the present invention, the energy storage system according to embodiments of the present invention charges DC power rectifying commercial power (AC) of a renewable energy generation facility and a system with a power storage device (PSS). ㆍDischarge and power conversion, receive the command of the DSP controller, convert the charging power of the PSS and discharge it to the load through the DC-capacitor, through communication control with the battery management system (BMS) that monitors and protects the PSS A bi-directional power conversion device (Bi-dPCS, 200) that controls charging and discharging of the PSS; A battery management device (BMS, 300) that serves to protect the PSS cells through the Bi-dPCS communication control and to stop charging when the input voltage is below a certain value; Direct/parallel so that multiple lithium ion batteries 410 and supercapacitors 420 that charge and discharge DC power of commercial power rectified with the new and renewable energy generation facilities by the Bi-dPCS and BMS can respond to the system load. A power storage device (PSS, 400) having one pack connected to each other; And a DSP controller (600) for controlling Bi-dPCS that detects the load on the system and controls the charging and discharging and bidirectional power conversion of the PSS. Here, the DSP controller may monitor the state of the DC-capacitor of the Bi-dPCS to charge the supercapacitor through the Bi-dPCS when an abnormal voltage occurs.

According to one embodiment, the Bi-dPCS. A battery converter 210 connected between the DC-capacitor and the lithium-ion battery to regulate charging and discharging of the lithium-ion battery; And a supercapacitor converter 220 connected between the DC-capacitor and the supercapacitor to interrupt 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 operate the supercapacitor converter 220 in response to the power error.

According to one embodiment, the DSP controller, the supercapacitor to charge the voltage to the supercapacitor in response to the power error, when the overpower is detected that the actual power (Pload) is greater than the reference power (Pref) Control the converter 220, if the actual power (Pload) is less than the reference power (Pref), to compensate for the power error to control the battery converter 210 to maintain the actual power (Pload) constant Can.

In order to achieve one object of the present invention, the output stabilization method of the energy storage system according to the embodiments of the present invention is a power storage device for rectifying DC power rectifying commercial power (AC) of a renewable energy generation facility and a system ( PSS) to charge/discharge and power, but with the command of the DSP controller, convert the charging power of the PSS and discharge it to the load through the DC-capacitor, and with the battery management system (BMS) that monitors and protects the PSS. A bi-directional power conversion device (Bi-dPCS, 200) that controls charging and discharging of the PSS through communication control; A plurality of lithium ion batteries 410 and supercapacitors 420 charging and discharging DC power of commercial power rectified with the new and renewable energy generation facilities by the Bi-dPCS are connected in series and in parallel to be able to cope with the system load. A power storage device (PSS, 400) having one pack; It may be performed in an energy storage system including a DSP controller 600 for controlling a Bi-dPCS that detects a system load and controls the charge/discharge and bidirectional power conversion of the PSS. The output stabilization method includes: monitoring the state of the DC-capacitor of the Bi-dPCS through the DSP controller; Comparing the actual power (Pload) in the DC-capacitor with a reference power (Pref) through the DSP controller; And when an overpower in which the actual power (Pload) in the DC-capacitor is greater than the reference power (Pref) is sensed, the supercapacitor corresponds to a power error between the actual power (Pload) and the reference power (Pref). It may include the step of buck operation for 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 through real-time monitoring of the state of the DC-capacitor to store energy through the buck operation of the supercapacitor energy storage device when an abnormal voltage occurs. have. Thus, 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 illustrating an energy storage system included in the power system of FIG. 1.
3 is a view for explaining a process of controlling the operation of the lithium-ion battery included in the energy storage system of FIG.
4 is a view for explaining a process of controlling the operation of the supercapacitor included in the energy storage system of FIG. 2.
5 is a flowchart illustrating an output stabilization method 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 skilled in the art to which the present invention pertains can easily practice. The present invention can be implemented in many different forms and is not limited to the embodiments described herein.

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

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

Referring to FIG. 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 bi-directional power conversion system (Bi-d PCS, Bidirectional Power Conditioning System), 200), including a battery management device (BMS, Battery Management System, 300), a power storage device (PSS, Power Storage System, 400), a system-side power conversion device 500 and a DSP controller (Digital Signal Processor Controller, 600) Can.

The renewable energy generation facility 100 is a means for generating electrical energy using energy of sunlight and wind, and the power produced by the solar power generation facility is direct current (DC), so it is a storage device such as a battery. Charging is possible, but the electricity produced by the wind power generation facility 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 a load other than the DC load, a process of converting it to AC is required. And in contrast to photovoltaic power generation, in case of wind power generation, rapid output fluctuation occurs depending on the wind speed, so it is charged with a storage device utilizing a high performance supercapacitor.

The bi-directional power conversion device (Bi-dPCS, Bidirectional Power Conditioning System, 200) outputs the power storage device so as not to lower the power conversion efficiency in order to convert the electrical energy stored in the power storage device 400 into commercial power ( DC power) as a means for converting the Bi-dPCS directly to AC or rectifying the power (AC) of the system directly from the Bi-dPCS to DC, and the commercial power (AC) of the renewable energy generation facility 100 and the system. ) Charges and discharges DC power rectified by a rectifier (or DC-capacitor) with a power storage device (PSS, 400) and converts power between DC and AC. At this time, under the command of the DSP controller 600, the charging power of the PSS 400 is directly converted to AC power and discharged 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, and the state of charge provided by the BMS (SOC) And the charging and discharging of the lithium ion battery 410 and the supercapacitor 420 of the PSS by using 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 and the supercapacitor of the PSS (400) ( 420) may include a rectifier (or DC-capacitor) for direct conversion to DC power.

The bi-directional power converter (Bi-dPCS, 200) is to convert the DC power discharged from the lithium ion battery 410 and the supercapacitor 420 of the PSS 400 into AC power directly to supply to the load. A three-level inverter is provided and is built into the bi-directional power converter (Bi-dPCS, 200) or the three-level inverter is not built into the bi-directional power converter (Bi-dPCS, 200). A wiring circuit may be configured to be connected to the system-side power conversion device 500.

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

As described above, when the renewable energy generation facility 100 and the system (commercial power supply) are connected, a power conversion device capable of converting DC (DC) to AC (AC) and AC (AC) to DC (DC) mutually ( PCS) is required, and a bi-directional power conversion system (Bi-dPCS, Bi-directional Power Conditioning System, 200) is implemented in an original manner.

On the other hand, in order to prolong the life of charging and discharging of the lithium ion battery 410 and the supercapacitor 420 of the power storage devices (PSS, 400), the charging state (SOC, State) of the power storage devices (PSS, 400) of charge) is important to keep constant. In addition, if the state of charge (SOC) is too low or high continues, deterioration of the lithium ion battery 410 and the supercapacitor 420 of the power storage devices PSS 400 is faster than when the SOC is maintained at an intermediate level. The range of the appropriate SOC can be determined through repeated experiments. In addition, when the cells of the lithium ion battery 410 and the supercapacitor 420 are over-discharged, the components deteriorate and become irrecoverable. In addition, when the charging voltage is also charged over the limit, the cells of the lithium ion battery 410 and the supercapacitor 420 are overheated and changed into an irreversible structure. The battery management device (BMS, 300), which will be described later, overcomes this problem.

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

In one embodiment, the bi-directional power conversion device (Bi-dPCS, 200) charges and discharges DC power to the lithium ion battery 410 and the supercapacitor 420 of the power storage device 400 by performing current control. In addition, it can be configured to be supported by a constant power control that receives and receives a current command from a higher-level controller and charges and discharges it with a 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 with the power storage device 400 to be charged and discharged to the same terminals (P+ and P-), through communication control with the Bi-dPCS The lithium ion battery 410 of the power storage devices (PSS, 400) and the maintenance of the balance (Balance) of each cell of the PSS and as a means to stop charging when the input voltage becomes below a certain value. Monitors the state of each cell of the supercapacitor 420, and protects the power storage device by incorporating a protection circuit for protecting it, and communicates with the Bi-dPCS 200 through the power storage device ( The state and operation information of each cell of the lithium ion battery 410 and the supercapacitor 420 of 400) are transferred to the PC monitor.

In addition, the battery management device (BMS, 300) is composed of a measurable structure for efficient operation, and monitors and protects the entire power storage device BMS and storage module and individual storage cell (Cell) monitoring and It can be configured with a module BMS to protect.

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

That is, the battery management device (BMS, Battery Management System, 300) can be largely divided into two. First, it controls the thermal management to achieve the same performance by uniformly cooling each cell by heat, and second, the charging state that determines the state of each cell and operates at the optimum efficiency point ( SOC) control. In these two control modes, since the rated voltage of a single cell of a lithium-ion battery is 3.6V and the charging voltage is 4.2V, a lithium-ion battery is connected in series to generate a voltage of several hundred volts or more. . When multiple 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 evenly charged state. This is because 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 measures to stabilize the system. It protects overcharge and overdischarge during charging and discharging of the battery, and uniformizes the voltage between cells to extend energy efficiency and battery life. In addition, it is possible to store the alarm-related history by diagnosing data preservation and system and diagnosis through a diagnostic system or monitoring PC. The function of the BMS 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 loads 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 devices PSS 400. As a means for converting to AC power for supply, the DC power supplied from the renewable energy generation facility 100 is converted to AC power to supply to the load.

In addition, the grid-side power converter 500 may apply a 3-phase inverter (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 bi-directional power converter that receives and receives information from a sensor (IoT) that senses load-side information connected to the 500 and intermittently charges and discharges the power storage device (PSS, 400) and intermittently converts bidirectional power between DC and AC (Bi-dPCS, 200).

The DSP controller 600, the signal for the DC power through the DC power and the system (commercial power) and rectifier (or DC-capacitor) of the new and renewable energy generation facility 100 that is first introduced into the connection panel 110 To receive the input and 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). Issue a control command. At this time, the bi-directional power conversion device (Bi-dPCS, 200) under the command of the DSP controller 600 receives the DC power connected to the connection panel 110 and the DC power passing through the rectifier with the lithium ion battery of the power storage device. Switch to each of the supercapacitors to charge the lithium-ion battery and the supercapacitor.

In addition, the DSP controller 600 receives the signal of a sensor (Iot) that detects a normal general load, such as a light load connected to the grid-side power converter 500 that supplies AC power to the grid load, and receives the power. Control commands are supplied to the bi-directional power converters (Bi-dPCS, 200) to supply the charging power charged to the lithium ion battery 410 and the supercapacitor 420 of the storage devices PSS 400 as a 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 controlled to be supplied to the system-side power conversion device 500.

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), the super capacitor of the power storage device (PSS, 400) ( The DC power charged in 420) is directly converted to AC power and supplied to a load or controlled to be supplied to the grid-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) to generate the bi-directional power conversion device (Bi-dPCS) when an abnormal voltage occurs due to load fluctuation. , 200) may charge the supercapacitor 420. For example, when an overpower in which the actual power (Pload) in the DC-capacitor is greater than the reference power (Pref) (or, command power, target power) is detected, the DSP controller 600 displays the actual power (Pload). ) And the bi-directional power conversion device (Bi-dPCS, 200) to charge the voltage to the supercapacitor 420 in response to a power error between the reference power (Pref). 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.

2, the energy storage system includes a DSP controller 600, a power storage device 400 (ie, a lithium ion battery 410 and a supercapacitor 420), and a bi-directional power conversion device (Bi-dPCS, 200). ).

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 is connected between the DC-capacitor C and the lithium-ion battery 410, and can 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 control charging and 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 is based on current/voltage information sensed through a plurality of sensors, and a power command (or Pdc_ref) for the lithium ion battery 410 (or command power, reference power, and target power), and a supercapacitor. A current command (Isc_ref) (or charging command) for 420 may be generated. Here, the current/voltage information includes the battery voltage (Vdc), the battery output current (Idc), the voltage (Vdc) of the DC-capacitor (C) (that is, the load-side voltage), the supercapacitor voltage (Vsc), and the supercapacitor output current ( Isc).

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

For example, the DSP controller 600, the super power to charge the voltage to the supercapacitor in response to the power error when the actual power (Pload) is detected that an overpower greater than the reference power (Pref) Capacitor converter 220 can be controlled. In addition, when the actual power (Pload) is less than the reference power (Pref), the DSP controller (600) compensates for the power error so that the actual power (Pload) is kept constant. Can be controlled.

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

First, referring to FIGS. 2 and 3, the DSP controller 600 compares power information (Pload) and power command (Pdc_ref) (or reference power) on the load side to calculate a power error, and calculates the PI by the power error. (Proportional integration) The output of the lithium ion battery 410 may be compensated or controlled through a controller.

For example, the DSP controller 600 (or the battery controller 610) is based on the voltage (Vdc) and the current (Idc) of the lithium-ion battery 410, the supply power (Pdc) (or, on the load side) Calculate power information (Pload), calculate the power error by calculating the power command (Pdc_ref) and supply power (Pdc), and generate a current command (Idc_ref) corresponding to the power error through the PI controller (PI) Then, the current command (Idc_ref) and the current information (Idc) can be calculated and the control signal for compensating for the power error 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 stage may be kept constant.

Referring to FIG. 4, the DSP controller 600 calculates a power error by comparing a reference power (Pdc_ref) (or a reference power, a power command) and an actual power (Pload), and through the current controller as much as the power error. The supercapacitor 420 can be charged with a voltage.

For example, the DSP controller 600 (or the supercapacitor controller 620) calculates a power error by differentially calculating the actual power Pload from the command power Pdc_ref (or the reference power and the power command). And generate a current command (Idc_ref) corresponding to the power error through the PI controller (PI), differentially calculate the current command (Idc_ref) and the output current (Isc), and control signals to compensate for the power error through the PI controller Can generate 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, as illustrated in FIG. 2, supercapacitor converter 220 ), the voltage at the DC-capacitor stage may be maintained at a constant level.

For example, the DSP controller 600, the super power to charge the voltage to the supercapacitor in response to the power error when the actual power (Pload) is detected that an overpower greater than the reference power (Pref) Capacitor converter 220 can be controlled. In addition, when the actual power (Pload) is less than the reference power (Pref), the DSP controller (600) compensates for the power error so that the actual power (Pload) is kept 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 real power Pload (or the state of a DC-capacitor) in real time, due to fluctuations in load. The output of the DC-capacitor can be stabilized through the buck operation of the supercapacitor 420 with respect to the generated abnormal voltage. In particular, the energy storage system, the supercapacitor converter 220 to charge the voltage to the supercapacitor in response to the power error when the actual power (Pload) is greater than the reference power (Pref) is detected By controlling, the voltage of the DC-capacitor can be maintained at a constant level.

5 is a flowchart illustrating an output stabilization method 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 the current/voltage information received through a separate sensor, and can check the occurrence of an abnormal voltage due to the load fluctuation.

In the method of FIG. 5, the actual power (Pload) in 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) By doing so, the two-way power converter (Bi-dPCS, 200) (or the supercapacitor converter 220) can be bucked with respect to the supercapacitor 420 (S530).

Alternatively, when the actual power Pload is smaller than the reference power Pref, the method of FIG. 5 controls the battery converter 210 to compensate for the power error so that the actual power Pload is kept constant. It can be done (S540).

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, so that repeated descriptions will not be repeated.

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

The drawings referenced so far and the detailed description of the described invention are merely exemplary of the present invention, which are used for the purpose of describing the present invention only and are used to limit the scope of the present invention as defined in the claims or the claims. It is not. Therefore, those of ordinary skill in the art will understand that various modifications and other equivalent 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 converter (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 converter
600: DSP controller

Claims (4)

DC power rectifying commercial power (AC) of new and renewable energy generation facilities and systems is charged/discharged and converted to power storage (PSS), but the power of the PSS is converted by converting the charging power of the PSS under the command of a DSP controller. A bi-directional power converter (Bi-dPCS, 200) that discharges to a load through a capacitor and controls charging and discharging of the PSS through communication control with a battery management system (BMS) that monitors and protects the PSS;
A battery management device (BMS, 300) that serves to protect the PSS cells through the Bi-dPCS communication control and to stop charging when the input voltage is below a certain value;
Direct/parallel so that multiple lithium ion batteries 410 and supercapacitors 420 that charge and discharge DC power of commercial power rectified with the new and renewable energy generation facilities by the Bi-dPCS and BMS can respond to the system load. A power storage device (PSS, 400) having one pack connected to each other;
It includes a DSP controller (600) for controlling the Bi-dPCS that detects the load of the system and controls the charging and discharging and bidirectional power conversion of the PSS,
The DSP controller monitors the state of the DC-capacitor of the Bi-dPCS and charges the supercapacitor through the Bi-dPCS when an abnormal voltage occurs.
According to claim 1, The Bi-dPCS.
A battery converter 210 connected between the DC-capacitor and the lithium-ion battery to regulate charging and discharging of the lithium-ion battery; And
And a supercapacitor converter (220) connected between the DC-capacitor and the supercapacitor to control charging and discharging of the supercapacitor,
The DSP controller calculates a power error between the reference power (Pref) and the actual power (Pload), and the energy storage system, characterized in that the buck operation of the supercapacitor converter 220 in response to the power error.
According to claim 2, The DSP controller,
When the overpower is detected that the actual power (Pload) is greater than the reference power (Pref), and controls the supercapacitor converter 220 to charge the voltage to the supercapacitor in response to the power error,
When the actual power (Pload) is less than the reference power (Pref), the energy storage system characterized in that to control the battery converter 210 to compensate for the power error to maintain the actual power (Pload) constant.
DC power rectifying commercial power (AC) of new and renewable energy generation facilities and systems is charged/discharged and converted to power storage (PSS), but the power of the PSS is converted by converting the charging power of the PSS under the command of a DSP controller. A bi-directional power converter (Bi-dPCS, 200) that discharges to a load through a capacitor and controls charging and discharging of the PSS through communication control with a battery management system (BMS) that monitors and protects the PSS; A plurality of lithium ion batteries 410 and supercapacitors 420 charging and discharging DC power of commercial power rectified with the new and renewable energy generation facilities by the Bi-dPCS are connected in series and in parallel to be able to cope with the system load. A power storage device (PSS, 400) having one pack; In the energy storage system including a DSP controller (600) for controlling the Bi-dPCS that detects the load on the system and controls the charge/discharge and bidirectional power conversion of the PSS,
Monitoring the state of the DC-capacitor of the Bi-dPCS through the DSP controller;
Comparing the actual power (Pload) in the DC-capacitor with a reference power (Pref) through the DSP controller; And
When an overpower in which the actual power (Pload) in the DC-capacitor is greater than the reference power (Pref) is sensed, for the supercapacitor in response to a power error between the actual power (Pload) and the reference power (Pref) And buck-operating the Bi-dPCS.

Images