Power control apparatus and method for controlling a DC-DC converter

Abstract

The power control apparatus and method according to an embodiment of the present invention may monitor an output power of a PCS, detect a change in a voltage of a DC link, and control an output power of a battery by comparing the output power of the PCS with a rated power of the battery, and thus provide stabilization of an energy storage system by preventing voltage fluctuations in the DC link.

Description

Technical Field

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2022-0116817 filed in the Korean Intellectual Property Office on September 16, 2022, and Korean Patent Application No. 10-2023-0122905 filed in the Korean Intellectual Property Office on September 15, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a power control device and method for controlling a DC / DC converter, and more particularly, to a power control device and method for controlling an output of a battery using a DC-DC converter to stabilize a voltage of a DC link. Background Art

[0003] Energy storage systems involve renewable energy, batteries that store electricity, and power grids. In recent years, as the popularity of smart grids and renewable energy is expanding and the efficiency and stability of power systems are gaining attention, the demand for energy storage systems in homes for power supply and demand control and power quality improvement is increasing. Typically, the output and capacity of home energy storage systems vary depending on the purpose of use.

[0004] For example, a home energy storage system is applied with a solar power generation system (photovoltaic; PV), and may include a battery segment consisting of a plurality of batteries, a battery management system (BMS) for battery management, a power conversion system (PCS), an energy management system (EMS), and a DC / DC converter, etc.

[0005] At the same time, in the home energy storage system, when the power consumption in the load exceeds the rated power, the PCS can be discharged to stabilize the load. Therefore, the voltage of the DC link unit may temporarily fluctuate, resulting in ripples.

[0006] Typically, a home energy storage system stabilizes the DC link by sending ripple current toward the grid when ripple appears in the DC link.

[0007] However, when a power outage occurs that limits the use of the grid, the home energy storage system cannot make the ripple current flow in the direction of the grid, which has the disadvantage of reducing the efficiency of the power delivered to the load.

[0008] In addition, when users start using loads in a power outage, a high peak voltage that temporarily exceeds the appropriate range may be generated in the DC link. Therefore, the PCS and multiple batteries in the traditional home energy storage system have the disadvantage of being shut down due to overvoltage to prevent failure. Summary of the invention

[0009] Technical issues

[0010] To avoid one or more problems of the related art, embodiments of the present disclosure provide a power control apparatus for controlling a DC / DC converter.

[0011] In order to avoid one or more problems of the related art, an embodiment of the present disclosure further provides a power control method for controlling a DC / DC converter.

[0012] To avoid one or more problems of the related art, an embodiment of the present disclosure provides an energy storage system including a power control device configured to control a DC / DC converter.

[0013] Technical Solution

[0014] To achieve the purpose of the present disclosure, a power control device is connected to a converter that performs direct current / direct current (DC / DC) conversion between a battery and a power conversion system (PCS), the power control device may include a memory and a processor, the processor executes at least one instruction in the memory, and the at least one instruction may include an instruction to detect the voltage of a DC link between an input end of the PCS and an output end of the converter; and an instruction to control the output power of the battery based on a change in the output power of the PCS, the change in the output power of the PCS being consistent with a change in the voltage of the DC link.

[0015] Here, the instruction to control the output power of the battery may include an instruction to control the output power of the battery by controlling the current of the battery.

[0016] Furthermore, the instruction to control the output power of the battery may include an instruction to control the battery to output power having a predefined peak power value when the output power of the PCS exceeds the output power of the battery.

[0017] Here, the instruction for controlling the battery to output power having a predefined peak power value may include: an instruction for comparing the difference between the output power of the PCS and the output power of the battery with a predefined threshold when the peak power output period of the battery is equal to or longer than a predefined first time period; and an instruction for controlling the battery to output power at a rated power when the difference is greater than or equal to the predefined threshold.

[0018] At the same time, instructions for controlling the battery to output power having a predefined peak power value may include: instructions for comparing the difference between the output power of the PCS and the output power of the battery with a predefined threshold when the peak power output period of the battery is equal to or longer than a predefined first time period; and instructions for controlling the battery to gradually output power to the rated power when the difference is less than the predefined threshold.

[0019] Here, the instruction to control the battery to gradually output power to the rated power may include an instruction to control the battery output power by gradually reducing the output power during a predefined second time period based on the peak power of the battery.

[0020] In addition, the instruction for controlling the battery to gradually output power to the rated power may also include: when the peak power output period exceeds a predefined second time period, the instruction for controlling the battery to output power at the rated power.

[0021] According to another embodiment of the present disclosure, a power control method performed by a power control device, which is connected to a converter that performs direct current / direct current (DC / DC) conversion between a battery and a power conversion system (PCS) and is configured to control the output power of the battery, the method may include detecting the voltage of a DC link between an input end of the PCS and an output end of the converter; and controlling the output power of the battery based on a change in the output power of the PCS, the change in the output power of the PCS being consistent with a change in the voltage of the DC link.

[0022] Controlling the output power of the battery may include controlling the output power of the battery by controlling the current of the battery.

[0023] Controlling the output power of the battery may include: when the output power of the PCS exceeds a predefined rated power of the battery, controlling the battery to output power having a predefined peak power value.

[0024] Controlling the battery to output power with a predefined peak power value may include: when the peak power output period of the battery is equal to or longer than a predefined first time period, comparing the difference between the output power of the PCS and the output power of the battery with a predefined threshold; and when the difference is greater than or equal to the predefined threshold, controlling the battery to output power at a rated power.

[0025] Controlling the battery to output power with a predefined peak power value may include: when the peak power output period of the battery is equal to or longer than a predefined first time period, comparing the difference between the output power of the PCS and the output power of the battery with a predefined threshold; and when the difference is less than the predefined threshold, controlling the battery to gradually output power to the rated power.

[0026] Controlling the battery to gradually output power to the rated power may include controlling the battery output power by gradually reducing the output power by a threshold power amount during a predefined second time period based on a peak power of the battery.

[0027] Controlling the battery to gradually output power to the rated power may include: when the peak power output period exceeds a predefined second time period, controlling the battery to output power at the rated power.

[0028] According to another embodiment of the present disclosure, an energy storage system may include: a battery rack; a plurality of converters configured to perform direct current / direct current (DC / DC) conversion in conjunction with the battery rack; a power conversion system (PCS) connected to the DC / DC converter and a load; and a power control device connected to the DC / DC converter and configured to control the operation of the DC / DC converter, wherein the converter is operated by the power control device, which is configured to detect the voltage of a DC link between an input end of the PCS and an output end of the converter, and control the output power of the battery rack based on changes in the output power of the PCS, wherein the changes in the output power of the PCS are consistent with changes in the voltage of the DC link.

[0029] The plurality of converters may be operated by a power control device to control the output power of the rack battery by controlling the current of the battery rack.

[0030] The plurality of converters may be operated by the power control device to: when the output power of the PCS exceeds a predefined rated power of the battery rack, control the battery to output power having a predefined peak power value.

[0031] Multiple converters can be operated by a power control device to: when the peak power output period of the battery rack is equal to or longer than a predefined first time period and the difference between the output power of the PCS and the rated power of the battery rack is equal to or greater than a predefined threshold, control the battery rack to output power at the rated power when the difference is greater than or equal to the predefined threshold.

[0032] Multiple converters can be operated by a power control device to: control the battery rack to gradually output power to the rated power when the peak power output period of the battery rack is equal to or longer than a predefined first time period and the difference between the output power of the PCS and the rated power of the battery rack is less than a predefined threshold.

[0033] The plurality of converters are operated by a power control device to control the battery rack output power by stepping down the output power by a threshold power amount during a predefined second time period based on the peak power of the battery rack.

[0034] The plurality of converters are operated by the power control device to control the battery to output power at a rated power when the peak power output period exceeds a predefined second time period.

[0035] Beneficial Effects

[0036] The power control device and method according to the embodiments of the present invention can monitor the output power of the PCS, detect changes in the voltage of the DC link, and control the output power of the battery by comparing the output power of the PCS with the rated power of the battery, and thus provide stabilization of the energy storage system by preventing voltage fluctuations in the DC link. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a block diagram of an energy storage system to which the present invention can be applied.

[0038] Figure 2 is a block diagram of the energy storage system in case of power outage.

[0039] Figure 3 is a block diagram of a power control apparatus according to an embodiment of the present invention.

[0040] Figure 4 is a flow chart of a power control method according to an embodiment of the present invention.

[0041] Figure 5 is a flowchart for explaining the steps of controlling the output power of a battery in a power control method according to an embodiment of the present invention.

[0042] Figure 6 is a block diagram for explaining a power control method according to an embodiment of the present invention.

[0043] Figure 7 is based on Figure 6 A graph of the voltage variation in the DC link over time.

[0044] Figure 8 is a flowchart explaining the steps of gradually controlling the output power of a battery in a power control method according to an embodiment of the present invention.

[0045] Fig. 9 is based on Figure 8 A graph of battery output power control over time.

[0046] Fig.10 is a block diagram for explaining a power control method according to another embodiment of the present invention.

[0047] Fig.11 is based on Fig.10 A graph of the voltage variation in the DC link over time.

[0048] 100: BMS

[0049] 200: BSC

[0050] 300: PMS

[0051] 400: PC

[0052] 500: DC / DC converter

[0053] 600: Power grid

[0054] 700: Load

[0055] M: Memory

[0056] P: Processor DETAILED DESCRIPTION

[0057] The present invention can be modified in various forms and has various embodiments, and its specific embodiments are shown by way of example in the accompanying drawings and will be described in detail below. However, it should be understood that it is not intended to limit the present invention to specific embodiments, but on the contrary, the present invention should cover all modifications, equivalents and substitutions that fall within the spirit and technical scope of the present invention. Throughout the description of the drawings, the same reference numerals refer to the same elements.

[0058] It should be understood that although various elements may be described herein using terms such as first, second, A, B, etc., these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and, similarly, a second element may be referred to as a first element without departing from the scope of the present invention. As used herein, the term "and / or" includes any combination of a plurality of associated listings or a plurality of associated listings.

[0059] It should be understood that when an element is referred to as being "coupled" or "connected" to another element, it can be directly coupled or connected to the other element, or there can be intervening elements. Conversely, when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements.

[0060] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "one", "an" and "the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include", "comprise", "include", "contain" and / or "have" are used herein to specify the existence of stated features, wholes, steps, operations, constituent elements, components and / or combinations thereof, but do not exclude the existence or addition of one or more other features, wholes, steps, operations, constituent elements, components and / or combinations thereof.

[0061] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It should also be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted as an idealized or overly formal meaning unless so explicitly defined herein.

[0062] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0063] Figure 1 is a block diagram of an energy storage system to which the present invention can be applied.

[0064] refer to Figure 1 , the basic unit of a battery that stores electricity in an energy storage system is generally a battery cell. A series / parallel combination of battery cells may form a battery pack, and a plurality of battery packs may form a battery rack. In other words, a battery rack may be a basic unit of a battery system constructed by combining battery packs in series / parallel. Here, a battery pack may be referred to as a battery module, depending on the device or system in which the battery is used. For example, Figure 1 The battery #1, battery #2, . . . , and battery #N shown in FIG. 1 may be in the form of a battery pack or a battery rack.

[0065] Here, a battery management system (BMS) 100 may be installed for each battery. The BMS 100 may monitor current, voltage, and temperature of each battery pack (or rack) to be managed, calculate a state of charge (SOC) of the battery based on the monitoring result to control charging and discharging.

[0066] Meanwhile, a battery system controller (BSC) may be located in each battery segment including a plurality of batteries, peripheral circuits, and devices. The battery system controller 200 may monitor and control objects such as voltage, current, temperature, and circuit breakers in the battery segment. In addition, the BSC 200 may calculate the output of each DC-DC converter based on the state information of the monitored battery and deliver it to at least one DC-DC converter.

[0067] In addition, a power conversion system (PCS) 400 installed in each battery section may control power supplied from the outside and power supplied from the battery section to the outside, thereby controlling charging and discharging of the battery. The power conversion system may include a DC / AC inverter.

[0068] In addition, the output of the DC / DC converter 500 may be connected to the PCS 400, and the PCS 400 may be connected to the grid 600 and the load 700. Here, the PCS 400 is generally operated in a constant power mode. A power management system (PMS) 300 connected to the PCS may control the output of the PCS based on the monitoring and control results of the battery management system or the battery system controller.

[0069] exist Figure 1 In the energy storage system of FIG. 4 , battery #1 is connected to DC / DC converter #1, battery #2 is connected to DC / DC converter #2, and battery #N is connected to DC / DC #N. The output of the DC / DC converter corresponding to each battery is connected to PCS 400 through a DC link.

[0070] The DC / DC converter may be a bidirectional converter in which, when performing conversion from a battery direction to a load direction, an input of the DC / DC converter is connected to a battery (battery cell, battery pack (module) or battery rack) and an output of the DC / DC converter may be connected to a load. As examples of the DC / DC converter, various types of converters such as a full-bridge converter, a half-bridge converter, and a flyback converter may be used.

[0071] At the same time, the communication between BMS 100, BSC 200, PMS 300 and PCS 400 can be carried out via Controller Area Network (CAN) or Ethernet (by Figure 1 This can be achieved by using the dashed line in the figure.

[0072] In such an energy storage system, a central controller within the system can usually calculate the output value of the battery at each moment and send the calculated value as a command to each battery (higher level control). However, higher level control can only be performed when the system voltage of the energy storage system is maintained, that is, lower level control is performed first.

[0073] Meanwhile, a DC link, which is a region between the DC / DC converter and the PCS, has a DC voltage, and the voltage of the DC link may generally be referred to as a system voltage.

[0074] For the stability of the entire energy storage system, the voltage of the DC link needs to be maintained at a constant level.

[0075] Figure 2 is a block diagram of the energy storage system in case of power outage.

[0076] refer to Figure 2 As described above, the power control device according to the embodiment of the present invention can control the DC / DC converter (500) to maintain the voltage of the DC link as the system voltage in a constant state.

[0077] Typically, when power consumption occurs in the load 700, the PCS 400 may output a power equal to that of Figure 1 The PCS 400 controls the output power to generate a ripple voltage of the DC link.

[0078] In addition, when power consumption exceeding rated power is generated from load 700, the voltage of the DC link may also fluctuate. Therefore, PCS 400 may receive additional power from grid 600 or output power to grid 600 to control the ripple voltage in the DC link to be maintained within an appropriate range.

[0079] However, when a power outage occurs, the use of the grid 600 may be limited, and thus the PCS 400 cannot receive power from the grid 600 and cannot transmit a ripple voltage toward the grid 600. Therefore, the power efficiency of the energy storage system may be reduced due to the ripple voltage.

[0080] In addition, in the event of a power outage, if a load is operated by a user without notice, a high peak voltage temporarily exceeding an appropriate range may be generated in the DC link. Therefore, each of the PCS 400 and the battery 500 may shut down its operation by a protection circuit due to the peak voltage to prevent malfunction.

[0081] Therefore, the power control device according to an embodiment of the present invention can use the DC / DC converter 500 to control the output of the battery 110, separately from the output control of the PCS 400, and therefore, when a power outage occurs in which the use of the power grid stops, the output power of the battery 110 is output at peak power, so that the control burden on the PCS 400 can be reduced even when the load is operated by the user without notification.

[0082] Furthermore, the power control device can improve the efficiency of the energy storage system by preventing system outages due to excessive ripple voltage in the DC link.

[0083] Figure 3 is a block diagram of a power control apparatus according to an embodiment of the present invention.

[0084] refer to Figure 3 , the power control device according to the embodiment of the present invention may be provided as Figure 2 The components may be within a battery system controller (BSC) 200, or may be provided as separate, independent components.

[0085] According to an embodiment, the power control device may monitor the output power of the PCS 400 and detect a change in the voltage of the DC link according to the operation of the load 700 .

[0086] In addition, the power control device may be connected to the DC / DC converter 500. Therefore, the power control device may control the DC / DC converter 500 so that the output power of the battery 110 is controlled according to the voltage variation of the DC link.

[0087] Meanwhile, the power control device may include a memory (M) and a processor (P).

[0088] According to an embodiment, the memory M may include at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory M may include at least one of a read-only memory (ROM) and a random access memory (RAM).

[0089] The memory M may include at least one instruction executed by the processor P.

[0090] According to an embodiment, the at least one instruction may include: an instruction to detect the voltage of a DC link between an input end of the PCS and an output end of the converter; and an instruction to control the output power of the battery based on a change in the output power of the PCS, the change in the output power of the PCS being consistent with a change in the voltage of the DC link.

[0091] Here, the instruction to control the output power of the battery may include an instruction to control the output power of the battery by controlling the current of the battery.

[0092] Furthermore, the instruction to control the output power of the battery may include an instruction to control the battery to output power having a predefined peak power value when the output power of the PCS exceeds the output power of the battery.

[0093] Here, the instruction for controlling the battery to output power having a predefined peak power value may include: an instruction for comparing the difference between the output power of the PCS and the output power of the battery with a predefined threshold when the peak power output period of the battery is equal to or longer than a predefined first time period; and an instruction for controlling the battery to output power at a rated power when the difference is greater than or equal to the predefined threshold.

[0094] At the same time, instructions for controlling the battery to output power having a predefined peak power value may include: instructions for comparing the difference between the output power of the PCS and the output power of the battery with a predefined threshold when the peak power output period of the battery is equal to or longer than a predefined first time period; and instructions for controlling the battery to gradually output power to the rated power when the difference is less than the predefined threshold.

[0095] Here, the instruction to control the battery output power to step to the rated power may include an instruction to control the battery output power by gradually reducing the output power during a predefined second time period based on the peak power of the battery.

[0096] In addition, the instruction for controlling the battery to gradually output power to the rated power may also include: when the peak power output period exceeds a predefined second time period, the instruction for controlling the battery to output power at the rated power.

[0097] Hereinafter, a power control method according to the operation of the processor P of the power control apparatus will be described in detail.

[0098] Figure 4 is a flow chart of a power control method according to an embodiment of the present invention.

[0099] refer to Figure 4 , the power control device according to the embodiment of the present invention can detect a voltage change in a DC link (S1000). Here, the DC link can be a region between an input terminal of the PCS (400) and an output terminal of the DC / DC converter (500).

[0100] Depending on the output power of the battery 110 and the operation timing of the load 700 , a voltage variation of the DC link in a power outage situation may occur.

[0101] According to an embodiment, when a user temporarily operates the load 700 before the output power of the battery 110 is lowered, a voltage variation may occur in the DC link.

[0102] According to another embodiment, when the user temporarily operates the load 700 after the output power of the battery 110 is reduced, a voltage variation may occur in the DC link.

[0103] Therefore, the power control device can detect the change in the voltage of the DC link by continuously monitoring the operating state of the load 700 and the change in the output power of the battery 110 .

[0104] Here, the operating state of the load 700 is controlled by the action of the user and thus is difficult to predict in advance. Meanwhile, the PCS 400 provides output power equal to the power consumption of the load 700 .

[0105] Therefore, the power control device can detect a change in the operating state of the load 700 by continuously monitoring a change in the output power of the PCS 400 .

[0106] When a voltage change in the DC link occurs, the power control device may compare the output power of the PCS 400 and the output power of the battery 110. In other words, the power control device may compare the power consumption of the load 700 and the output power of the battery 110. Therefore, the power control device may use the DC / DC converter 500 to control the size and speed of the output power of the battery 110 according to the comparison result (S5000). For example, the DC / DC converter 500 may be a bidirectional converter.

[0107] How the power control device controls the magnitude and speed of the output power of the battery 110 through the DC / DC converter 500 will be described in more detail below.

[0108] Figure 5 is a flowchart for explaining the steps of controlling the output power of a battery in a power control method according to an embodiment of the present invention.

[0109] refer to Figure 5 , the power control apparatus according to the embodiment of the present invention may compare the output power of the PCS 400 and the output power of the battery 110 ( S5100 ).

[0110] According to an embodiment, when the output power value of the PCS 400 is less than or equal to the output power value of the battery 110, it can be determined that the power consumption of the load 700 is reduced under the control of the user. Therefore, the power control device can control the current amount of the DC / DC converter 500 (S5200) to quickly reduce the output power of the battery 110 at a higher speed than the predefined reference speed.

[0111] Figure 6 is a block diagram for explaining a power control method according to an embodiment of the present invention. Figure 7 is based on Figure 6 A graph of the voltage variation in the DC link over time.

[0112] refer to Figure 6 and Figure 7 , when the power consumption of the load 700 decreases, the output power of the battery 110 is greater than the power consumption of the load 700, and therefore, a voltage change of the DC link may occur ( Figure 7 Segment A in ).

[0113] Therefore, the power control device can quickly reduce the output power of the battery 110 by controlling the current amount of the battery 110 at a high speed using the DC / DC converter 500 ( Figure 7 Therefore, the voltage of the DC link can be stabilized.

[0114] Reference again Figure 5 According to another embodiment, when the output power value of the PCS 400 exceeds the output power value of the battery 110 , the power control device may operate the DC / DC converter 500 to control the battery 110 to output peak power ( S5300 ) in order to prepare for unexpected operation of the load 700 .

[0115] Typically, when powered, the load 700 may temporarily consume peak power, and then consume the predefined rated power again. However, the operation timing of the load 700 may be unpredictable. Therefore, when the output power of the battery 110 becomes lower than the output power of the PCS 400, the power control device according to an embodiment of the present invention may first control the battery 110 to operate at peak power for a preset time. Here, the peak power of the battery 110 may be the power provided from the battery 110 to support an output power higher than the rated power temporarily generated at the initial time of applying power to the load 700. For example, the peak power may be 11kW. However, since the load 700 operates under the control of the user, the power control device cannot predict the operating time of the load. In addition, since the battery 110 has a limited charging capacity, the battery can only provide the maximum peak power within a limited period of time.

[0116] According to an embodiment, when the peak power output time period of the battery 110 is less than the preset first time period (P1) (S5400), the process returns to step S5100 and continuously monitors the voltage change in the DC link by comparing the output power of the PCS 400 and the rated power of the battery 110. For example, the first time period (P1) may be 9.6 seconds.

[0117] Meanwhile, according to another embodiment, when the peak power output time period of the battery 110 is equal to or longer than a preset first time period (P1) (S5400), the power control device may compare the difference between the output power of the PCS 400 and the output power of the battery 110 at the current time with a predetermined threshold value (S5500).

[0118] Here, when the difference between the output power of the PCS 400 and the output power of the battery 110 is less than a predetermined threshold power amount (S5500), the power control device may determine that the load 700 can be stably powered by the PCS 400. Therefore, the power control device may reduce the output power of the battery 110 to the rated power through the DC / DC converter 500 (S5600).

[0119] Meanwhile, when the difference between the output power of the PCS 400 and the output power of the battery 110 is equal to or greater than a predetermined threshold value (S5500), the power control device may determine that it is difficult to stably supply power to the load 700 using only the output power of the PCS 400. Therefore, the power control device may gradually reduce the output power of the battery 110 through the DC / DC converter 500 so as to reduce the control burden of the PCS 400 (S5700). In other words, the power control device may reduce the output power of the battery 110 to a speed lower than the predefined reference speed.

[0120] Figure 81 is a flowchart explaining the steps of gradually controlling the output power of a battery in a power control method according to an embodiment of the present invention. Fig. 9 is based on Figure 8 A graph of battery output power control over time.

[0121] refer to Figure 8 and Fig. 9 When the difference between the output power of the PCS 400 and the output power of the battery 110 is greater than or equal to a predetermined threshold value (S5500), the power control device may control the DC / DC converter 500 to reduce the output power of the battery 110 by a predefined threshold power amount (S5710). Here, the predefined threshold power amount may be 100W.

[0122] Thereafter, the power control device may control the DC / DC converter 500 to maintain the output power of the battery 110 for a predetermined period of time (S5730). For example, the DC / DC converter 500 may maintain the output power reduced by a predefined threshold power amount for 10ms.

[0123] In other words, the power control device may gradually reduce the output power of the battery by a predefined threshold power amount through the DC / DC converter 500 using step logic at each preset cycle.

[0124] Thereafter, the power control device may compare the peak power output period with the second time period (P2) (S5750). Here, the second time period (P2) may be a threshold time period during which the output power of the battery may be output at a value greater than the rated power. For example, the second time period (P2) may be 10 seconds.

[0125] According to an embodiment, when the peak power output time period of the battery 110 reaches the second time period (P2), the power control device may adjust the output power of the battery 110 to the rated power (Max Continuous) (S5770) through the DC / DC converter 500. For example, the rated power of the battery 110 may be 7 kW.

[0126] Here, the rated power can be preset to any value within the rated power output range (see Figure 7 In other words, the output range of the rated power may fall within the output power control range of the PCS 400 to stabilize the voltage of the DC link. Therefore, the power control device may control the output power of the battery 110 by gradually reducing the output power of the battery by a threshold power amount via the DC / DC converter 500 until the power control period reaches the second period (P2).

[0127] Meanwhile, according to another embodiment, if the peak power output time period of the battery 110 is different from the second time period (P2), the power control device may return to step S5100 and compare the voltage of the output power PCS 400 and the output power of the battery, thereby continuously monitoring the voltage change in the DC link.

[0128] Fig.10 is a block diagram for explaining a power control method according to another embodiment of the present invention. Fig.11 is based on Fig.10 A graph of the voltage variation in the DC link over time.

[0129] refer to Fig.10 and Fig.11 ,like Figure 5 As in step S5300 of the embodiment, when the output power value of the battery 110 is less than the output power value of the PCS 400, the power control device can control the DC / DC converter 500 to operate the battery 110 at the peak power to prepare for the case where the load 700 is accidentally operated by the user. Therefore, when the user operates the load 700 during the peak power output period of the battery 110, the battery 110 can stably supply power despite the temporary peak power consumption of the load 700.

[0130] At the same time, the power control device gradually reduces the output of the peak power to prepare for the load 700 operating after the peak power output period of the battery 110. Therefore, when the load 700 is operated during the second period P2 after the peak power output period of the battery 110, the power control device can output the power of the battery 110 higher than the rated voltage, and thus, the DC link ( Fig.11 The A and B segments in the image can be minimized.

[0131] The power control apparatus and method according to the embodiments of the present invention have been described above.

[0132] The power control device and method according to the embodiments of the present invention can monitor the output power of the PCS, detect changes in the voltage of the DC link, and control the output power of the battery by comparing the output power of the PCS with the rated power of the battery, and thus provide stabilization of the energy storage system by preventing voltage fluctuations in the DC link.

[0133] The operation of the method according to an embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. The computer-readable recording medium includes all types of recording devices that store data readable by a computer system. In addition, the computer-readable recording medium can be distributed in a network-connected computer system to store and execute a computer-readable program or code in a distributed manner.

[0134] In addition, the computer-readable recording medium may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. The program instructions may include not only machine language codes created by a compiler, but also high-level language codes that can be executed by a computer using an interpreter.

[0135] Although some aspects of the present invention have been described in the context of an apparatus, it may also be represented as a description according to a corresponding method, wherein a block or apparatus corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also represent features of a corresponding block or item or a corresponding apparatus. Some or all of the method steps may be performed by (or using) hardware devices such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0136] In the foregoing, the present invention has been described with reference to exemplary embodiments thereof, but those skilled in the art will appreciate that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention described in the appended claims.

Claims

1. A power control device, the power control device being connected to a converter that performs direct current / direct current (DC / DC) conversion between a battery and a power conversion system (PCS), the power control device being configured to control output power of the battery, the device comprising: Memory; as well as a processor, the processor executing at least one instruction in the memory, The at least one instruction comprises: an instruction to detect a voltage of a DC link between an input terminal of the PCS and an output terminal of the converter; as well as The command for controlling the output power of the battery is controlled based on a change in the output power of the PCS, the change in the output power of the PCS being consistent with a change in the voltage of the DC link.

2. The device according to claim 1, wherein: The instructions for controlling the output power of the battery include instructions for controlling the output power of the battery by controlling the current of the battery.

3. The device according to claim 1, wherein: The instruction for controlling the output power of the battery includes an instruction for controlling the battery to output power having a predefined peak power value when the output power of the PCS exceeds the output power of the battery.

4. The device according to claim 3, wherein: The instruction for controlling the battery to output power having the predefined peak power value includes: instructions for comparing a difference between the output power of the PCS and the output power of the battery with a predefined threshold when the peak power output period of the battery is equal to or longer than a predefined first time period; and In a case where the difference is greater than or equal to the predefined threshold, an instruction is provided to control the battery to output power at a rated power.

5. The device according to claim 3, wherein: The instruction for controlling the battery to output power having the predefined peak power value includes: instructions for comparing a difference between the output power of the PCS and the output power of the battery with a predefined threshold when the peak power output period of the battery is equal to or longer than a predefined first time period; and In the case where the difference is less than the predefined threshold, the battery is controlled to gradually output power to a rated power.

6. The device according to claim 5, wherein: The instructions for controlling the battery to gradually output power to the rated power include: Instructions for controlling output power of the battery by stepping down the output power by a threshold power amount during a predefined second time period based on a peak power of the battery.

7. The device according to claim 6, wherein: The instruction for controlling the battery to gradually output power to the rated power also includes: When the peak power output period exceeds the predefined second time period, the battery is controlled to output power at a rated power.

8. A power control method performed by a power control device, the power control device being connected to a converter performing direct current / direct current (DC / DC) conversion between a battery and a power conversion system (PCS) and configured to control output power of the battery, the method comprising: detecting a voltage of a DC link between an input terminal of the PCS and an output terminal of the converter; as well as The output power of the battery is controlled based on a change in the output power of the PCS, the change in the output power of the PCS being consistent with a change in the voltage of the DC link.

9. The method according to claim 8, wherein: Controlling the output power of the battery includes controlling the output power of the battery by controlling a current of the battery.

10. The method according to claim 8, wherein: Controlling the output power of the battery includes: when the output power of the PCS exceeds a predefined rated power of the battery, controlling the battery to output power having a predefined peak power value.

11. The method according to claim 10, wherein: Controlling the battery to output power having the predefined peak power value comprises: When the peak power output period of the battery is equal to or longer than a predefined first time period, comparing a difference between the output power of the PCS and the output power of the battery with a predefined threshold; and When the difference is greater than or equal to the predefined threshold, the battery is controlled to output power at a rated power.

12. The method according to claim 10, wherein: Controlling the battery to output power having a predefined peak power value comprises: When the peak power output period of the battery is equal to or longer than a predefined first time period, comparing a difference between the output power of the PCS and the output power of the battery with a predefined threshold; and When the difference is smaller than the predefined threshold, the battery is controlled to gradually output power to a rated power.

13. The method according to claim 12, wherein: Controlling the battery to gradually output power to a rated power includes: The battery output power is controlled by stepping down the output power by a threshold power amount during a predefined second time period based on a peak power of the battery.

14. The method according to claim 13, wherein: Controlling the battery to gradually output power to a rated power includes: When the peak power output period exceeds the predefined second time period, the battery is controlled to output power at a rated power.

15. An energy storage system comprising: Battery rack; a plurality of converters configured to perform direct current / direct current (DC / DC) conversion in conjunction with the battery rack; a power conversion system (PCS), the power conversion system (PCS) being connected to the DC / DC converter and a load; as well as a power control device connected to the DC / DC converter and configured to control the operation of the DC / DC converter, Wherein, the converter is operated by the power control device, which is configured to detect the voltage of the DC link between the input end of the PCS and the output end of the converter and control the output power of the battery rack based on the change of the output power of the PCS, and the change of the output power of the PCS is consistent with the change of the voltage of the DC link.

16. The system of claim 15, wherein: The plurality of converters are operated by the power control device to control the output power of the battery by controlling the current of the battery rack.

17. The system of claim 15, wherein: The plurality of converters are operated by the power control device to control the battery rack to output power having a predefined peak power value when the output power of the PCS exceeds a predefined rated power of the battery rack.

18. The system of claim 17, wherein: The plurality of converters are operated by the power control device to: When the peak power output period of the battery rack is equal to or longer than a predefined first time period and the difference between the output power of the PCS and the rated power of the battery rack is equal to or greater than a predefined threshold, When the difference is greater than or equal to the predefined threshold, the battery rack is controlled to output power at a rated power.

19. The system of claim 17, wherein: The plurality of converters are operated by the power control device to: When the peak power output period of the battery rack is equal to or longer than a predefined first time period and the difference between the output power of the PCS and the rated power of the battery rack is less than a predefined threshold, The battery rack is controlled to gradually output power to the rated power.

20. The system of claim 19, wherein: The plurality of converters are operated by the power control device to: The battery rack output power is controlled by stepping down the output power by a threshold power amount during a predefined second time period based on a peak power of the battery rack.

21. The system of claim 20, wherein: The plurality of converters are operated by the power control device to: When the peak power output period exceeds a predefined second time period, the battery rack is controlled to output power at a rated power.

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