System control apparatus and system control method for battery charging-discharging system

Abstract

Provided are a system control apparatus and a system control method for a battery charging-discharging system. The battery charging-discharging system comprises first to m-th charging-discharging groups. Each charging-discharging group comprises a plurality of equipment sets connected via a DC power channel. Each equipment set comprises a converter and a charger / discharger. The system control apparatus comprises a controller for monitoring first to m-th group state information of the first to m-th charging-discharging groups. On the basis of the first to m-th group state information, the controller compares, with a reference load factor range, the load factors of the charging-discharging groups in operation among the first to m-th charging-discharging groups, and controls the operation mode of each of the converters of the plurality of equipment sets included in the charging-discharging groups in operation. m is a natural number greater than or equal to 2.

Description

System control device and system control method for a battery charging / discharging system

[0001] The present invention relates to a control technology for improving the efficiency of a charging / discharging process performed by a battery charging / discharging system.

[0002] This application claims priority to Korean Patent Application No. 10-2024-0043627, filed March 29, 2024, and Korean Patent Application No. 10-2025-0038055, filed March 25, 2025, the entire contents of which are disclosed in the specification and drawings of the aforementioned applications are incorporated herein by reference.

[0003] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage batteries, robots, and satellites has been in full swing, research into high-performance batteries capable of repeated charging and discharging is actively being conducted.

[0004] Currently commercialized batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium batteries. Among these, lithium batteries are receiving attention for their advantages of being able to charge and discharge freely, having a very low self-discharge rate, and having a high energy density, as they have almost no memory effect compared to nickel-based batteries.

[0005] Batteries are shipped as finished products after sequentially undergoing assembly and charge / discharge processes. During the assembly process, a stack of positive electrodes, negative electrodes, and separators are housed and sealed in an outer case along with an electrolyte. During the charge / discharge process for battery formation, the assembled battery undergoes a specific charge / discharge procedure. This process forms a solid electrolyte interphase (SEI) on the surface of the battery's negative electrode, imparting the intended electrical properties.

[0006] Batteries that have completed the assembly process are sequentially transported to the battery charging / discharging system, and the battery charging / discharging system sequentially performs the charging / discharging process on the batteries in a first-in, first-out manner.

[0007] The battery charging / discharging system includes multiple charging / discharging groups, each dedicated to individual charging / discharging processes for battery trays. Because the battery charging / discharging system requires a large amount of power to operate, minimizing unnecessary power loss is crucial.

[0008] The present invention has been devised to solve the above-mentioned problems, and its purpose is to provide a device and method for adaptively adjusting the number of converters that require operation while a battery charging / discharging system is in operation, thereby optimizing the power conversion efficiency of each converter.

[0009] In addition, the present invention aims to provide a device and method for individually controlling a plurality of charge / discharge groups so as to minimize unnecessary power loss while the battery charge / discharge system is in operation.

[0010] Other objects and advantages of the present invention can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0011] A system control device according to one aspect of the present invention is for a battery charging / discharging system. The battery charging / discharging system includes first to mth charging / discharging groups. Each charging / discharging group includes a plurality of equipment sets connected via a DC power channel. Each equipment set includes a converter and a charger / discharger.

[0012] The system control device includes a controller configured to monitor status information of the first to m-th charge / discharge groups of the first to m-th charge / discharge groups. The controller is configured to compare the load rate of each charge / discharge group in operation among the first to m-th charge / discharge groups with a reference load rate range based on the status information of the first to m-th groups, and to control the operation mode of each converter of the plurality of equipment sets included in each charge / discharge group in operation. m is a natural number greater than or equal to 2.

[0013] The controller may be configured to switch one converter of the i-th charge / discharge group from an idle mode to a power supply mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a charge-dominant state and the load rate of the i-th charge / discharge group exceeds the upper limit of the reference load rate range. i is a natural number less than or equal to m.

[0014] The controller may be configured to determine the priority of two or more converters in the idle mode among the plurality of chargers and dischargers of the i-th charge / discharge group when the load rate of the i-th charge / discharge group exceeds the upper limit of the reference load rate range while the i-th charge / discharge group is operating in a charge-dominant state, and to switch one converter with the highest priority among the two or more converters in the idle mode to the power supply mode.

[0015] The controller may be configured to switch one converter of the i-th charge / discharge group from a power supply mode to an idle mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a charge-dominant state and the load rate of the i-th charge / discharge group falls below the lower limit of the reference load rate range. i is a natural number less than or equal to m.

[0016] The controller may be configured to determine the priority of two or more converters in a power supply mode among a plurality of chargers and dischargers of the i-th charge / discharge group when the load rate of the i-th charge / discharge group falls below the lower limit of the reference load rate range while the i-th charge / discharge group is operating in a charge-dominant state, and to switch one converter with the highest priority among the two or more converters in the power supply mode to the idle mode.

[0017] The controller may be configured to switch one converter of the i-th charge / discharge group from an idle mode to a power recovery mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a discharge-dominant state and the load ratio of the i-th charge / discharge group exceeds the upper limit of the reference load ratio range. i is a natural number less than or equal to m.

[0018] The controller may be configured to determine the priority of two or more converters in the idle mode among the plurality of chargers and dischargers of the i-th charge / discharge group when the load ratio of the i-th charge / discharge group exceeds the upper limit of the reference load ratio range while the i-th charge / discharge group is operating in a discharge-dominant state, and to switch one converter with the highest priority among the two or more converters in the idle mode to the power regeneration mode.

[0019] The controller may be configured to switch one converter of the i-th charge / discharge group from a power recovery mode to an idle mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a discharge-dominant state and the load ratio of the i-th charge / discharge group falls below the lower limit of the reference load ratio range. i is a natural number less than or equal to m.

[0020] The controller may be configured to determine the priority of two or more converters in the power regeneration mode among the plurality of chargers and dischargers of the i-th charge / discharge group when the load ratio of the i-th charge / discharge group falls below the lower limit of the reference load ratio range while the i-th charge / discharge group is operating in a discharge-dominant state, and to switch one converter with the highest priority among the two or more converters in the power regeneration mode to the idle mode.

[0021] The controller may be configured to select, when two or more of the first to mth charge / discharge groups are in a battery insertion state, one charge / discharge group having the greatest discharge superiority state among the two or more charge / discharge groups in the battery insertion state. The controller may be configured to set, among the plurality of chargers / dischargers in the selected charge / discharge group, one charger / discharger in a battery non-input state as the highest priority battery insertion target.

[0022] The controller may be configured to set, when at least two chargers and dischargers of a charging and discharging group having the maximum discharge dominant state are in the battery non-input state, one of the two or more chargers and dischargers in the battery non-input state that is closest to a predetermined battery input point as the highest priority battery input target.

[0023] The controller may be configured to prohibit the battery charging mode for each of the remaining chargers and dischargers in the i-th charge and discharge group when the first number of chargers and dischargers adjacent to each other among the plurality of chargers and dischargers in the i-th charge and discharge group among the first to m-th charge and discharge groups are in the battery charging mode.

[0024] The controller may be configured to prohibit the battery discharge mode for each of the remaining chargers and dischargers in the i-th charge and discharge group when a second number of chargers and dischargers adjacent to each other among the plurality of chargers and dischargers in the i-th charge and discharge group are in the battery discharge mode.

[0025] A system control method according to another aspect of the present invention is for the battery charging / discharging system. The system control method includes the steps of monitoring status information of the first to m-th charge / discharge groups of the first to m-th charge / discharge groups, and the step of comparing the load ratio of each operating charge / discharge group among the first to m-th charge / discharge groups with a reference load ratio range based on the status information of the first to m-th groups, thereby controlling the operation mode of each converter of the plurality of equipment sets included in each operating charge / discharge group.

[0026] The step of controlling the operation mode of each converter of the plurality of equipment sets included in each of the above-described operating charge / discharge groups may include a step of switching any converter of the i-th charge / discharge group from an idle mode to a power supply mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a charge-dominant state and the load rate of the i-th charge / discharge group exceeds the upper limit of the reference load rate range. i is a natural number less than or equal to m.

[0027] The step of controlling the operation mode of each converter of the plurality of equipment sets included in each of the above-described operating charge / discharge groups may include a step of switching any converter of the i-th charge / discharge group from a power supply mode to an idle mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a charge-dominant state and the load rate of the i-th charge / discharge group falls below the lower limit of the reference load rate range. i is a natural number less than or equal to m.

[0028] According to at least one of the embodiments of the present invention, while the battery charging / discharging system is in operation, the number of converters that require operation in power supply mode or power recovery mode for each charging / discharging group can be adaptively adjusted according to the load ratio for each charging / discharging group, thereby optimizing the power conversion efficiency of each converter.

[0029] Furthermore, according to at least one embodiment of the present invention, while the battery charging / discharging system is in operation, unnecessary power losses can be minimized by individually controlling multiple charging / discharging groups so that at least one converter and at least one charger / discharger can exchange power through the shortest possible power path. Furthermore, heat generation associated with line losses can be reduced, thereby improving operational reliability.

[0030] In addition, according to at least one of the embodiments of the present invention, by selecting a battery input target with the highest priority among a plurality of chargers and dischargers of a charge / discharge group having the highest discharge dominant state, the discharge dominant state of the corresponding charge / discharge group can be alleviated.

[0031] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0032] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0033] Figures 1 to 3 are drawings for reference in explaining the overall configuration of a battery charging / discharging system (10) according to one embodiment of the present invention.

[0034] FIG. 4 is a drawing schematically showing an exemplary arrangement relationship of charge / discharge groups of the battery charge / discharge system (10) illustrated in FIG. 1.

[0035] FIG. 5 is a flowchart schematically illustrating a system control method according to another embodiment of the present invention.

[0036] FIG. 6 is a flowchart schematically illustrating an example of subroutines that may be included in step S520 of FIG. 5.

[0037] FIG. 7 is a flowchart schematically illustrating an example of subroutines that may be included in step S630 of FIG. 6.

[0038] FIG. 8 is a flowchart schematically illustrating another example of subroutines that may be included in step S520 of FIG. 5.

[0039] FIG. 9 is a flowchart schematically illustrating an example of subroutines that may be included in step S830 of FIG. 8.

[0040] FIG. 10 is a flowchart schematically illustrating another example of subroutines that may be included in step S520 of FIG. 5.

[0041] FIG. 11 is a flowchart schematically illustrating an example of subroutines that may be included in step S1030 of FIG. 10.

[0042] FIG. 12 is a flowchart schematically illustrating another example of subroutines that may be included in step S520 of FIG. 5.

[0043] FIG. 13 is a flowchart schematically illustrating an example of subroutines that may be included in step S1230 of FIG. 12.

[0044] Figure 14 is a flowchart schematically illustrating a system control method according to another embodiment of the present invention.

[0045] FIG. 15 is a drawing referenced for explaining the circuit configuration and function of the main smoothing circuit and sub smoothing circuit shown in FIG. 1.

[0046] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that conforms to the technical spirit of the present invention.

[0047] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0048] Terms that include ordinal numbers, such as first, second, etc., are used to distinguish one of the various components from the rest, and are not used to limit the components by such terms.

[0049] Throughout the specification, when a part is said to "include" a component, this does not exclude other components, unless otherwise stated, but rather implies that other components may be included. Furthermore, terms such as "unit" used throughout the specification mean a unit that processes at least one function or operation, and may be implemented using hardware, software, or a combination of hardware and software.

[0050] Additionally, throughout the specification, when we say that a part is "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is "indirectly connected" with other elements in between.

[0051] FIGS. 1 to 3 are drawings for reference in explaining the overall configuration of a battery charging / discharging system (10) according to one embodiment of the present invention, and FIG. 4 is a drawing schematically showing an exemplary arrangement relationship of charging / discharging groups of the battery charging / discharging system (10) illustrated in FIG. 1.

[0052] Referring to FIGS. 1 to 4, the battery charging / discharging system (10) includes first to mth charging / discharging groups (G1 to Gm) and a system control device (100). m is a natural number greater than or equal to 2. The battery charging / discharging system (10) may further include a stacker crane (SC).

[0053] When i is a natural number less than or equal to m, the charge / discharge group (Gi) includes the first to nth equipment sets (Ei-1 to Ei-n). m is a natural number greater than or equal to 2. The equipment sets (Ei-1 to Ei-n) can be electrically coupled via a DC power channel (BPi) to enable bidirectional power supply therebetween. The charge / discharge group (Gi) may further include an auxiliary power source (Wi) electrically coupled to the equipment sets (Ei-1 to Ei-n) via the DC power channel (BPi). The auxiliary power source (Wi) is not particularly limited in type as long as it has a storage function and a supply function of electric energy, such as a battery bank or an ESS (Energy Storage System). Meanwhile, in FIGS. 2 and 3, the DC power channel (BPi) is illustrated as a single line, but in reality, it may be a pair of (+) lines and (-) lines. Additionally, in the present invention, each line may be implemented as one or a combination of a busbar and an electric cable.

[0054] When j is a natural number less than or equal to n, a set of equipment (Ei-j) of a charge / discharge group (Gi) includes a converter (Pi-j) and a charger / discharger (Ci-j). A pair of lines of a DC power channel (BPi) can be directly or indirectly coupled to a pair of DC input / output terminals provided in the converter (Pi-j) and a pair of DC input / output terminals provided in the charger / discharger (Ci-j). The converter (Pi-j) may be provided with AC input / output terminals for coupling with an AC power grid (1). The charger / discharger (Ci-j) may additionally be provided with a pair of DC input / output terminals for coupling with a pair of DC input / output terminals provided in a battery tray (BT).

[0055] The equipment set (Ei-j) may further include at least one of a main smoothing circuit (HAi-j) and a sub smoothing circuit (HBi-j).

[0056] In FIG. 3, the equipment set (Ei-j) is shown to include only a single charger / discharger (Ci-j), but may further include at least one additional charger / discharger electrically connected in parallel to the charger / discharger (Ci-j) via a DC power channel (BPi).

[0057] The converter (Pi-j) is electrically coupled to the AC power grid (1) via the AC power channel (APi). When operating in a power supply mode, the converter (Pi-j) converts AC power supplied from the AC power grid (1) into DC power and supplies the converted AC power to the DC power channel (BPi). When operating in a power regeneration mode, the converter (Pi-j) converts DC power supplied through the DC power channel (BPi) into AC power and supplies the converted AC power to the AC power grid (1). The converter (Pi-j) may also be referred to as a 'power conversion facility'.

[0058] The voltage of the DC power supplied from the converter (Pi-j) to the DC power channel (BPi) can be maintained at a reference voltage (which may be preset to, for example, 370 V) by feedback control.

[0059] The converter (Pi-j) includes an AC-DC converter. The system control device (100) can perform on / off control on the AC-DC converter or adjust the size of the direct current power supplied from the converter (Pi-j) to the DC power channel (BPi) depending on the status of the AC power grid (1).

[0060] The charger / discharger (Ci-j) may include at least one bidirectional DC-DC converter. The charger / discharger (Ci-j) may relay bidirectional power transfer between the battery tray (BT) and the DC power channel (BPi) transferred thereto.

[0061] Referring to FIG. 15, when the charger / discharger (Ci-j) operates in battery charging mode, the charger / discharger (Ci-j) converts direct current power supplied through a pair of DC power terminals arranged to be connected to the converter (Pi-j) side into charging power having a predetermined voltage level, and then outputs the same to a pair of DC power terminals arranged to be connected to the battery tray (BT) side. When the charger / discharger (Ci-j) operates in battery discharging mode, the charger / discharger (Ci-j) converts discharge power of the battery tray (BT) supplied through a pair of DC power terminals arranged to be connected to the battery tray (BT) side into direct current power having a predetermined voltage level, and then outputs the same to a pair of DC power terminals arranged to be connected to the converter (Pi-j) side.

[0062] The battery charging / discharging system (10) includes m charging / discharging groups (G1 to Gm), each charging / discharging group includes n sets of equipment, and each set of equipment includes q (q is a natural number greater than or equal to 1) chargers / dischargers, so that individual charging / discharging processes for up to m×n×q battery trays (BT) can be simultaneously performed by the charging / discharging groups (G1 to Gm).

[0063] The charge / discharge process comprises at least one charging stage and at least one discharging stage, which are performed alternately. When the charge / discharge process is initiated, the charging stage is performed first, followed by the discharging stage. Each charging stage may include at least one of a constant current charging procedure, a constant power charging procedure, and a constant voltage charging procedure. Each discharging stage may include at least one of a constant current discharging procedure, a constant power discharging procedure, and a constant voltage discharging procedure.

[0064] After going through the assembly process, each battery tray (BT) sequentially transferred to the battery charging / discharging system (10) undergoes a charging / discharging process by one of the chargers / dischargers of the battery charging / discharging system (10) according to the first-in, first-out method.

[0065] Additionally, the charger / discharger included in a set of equipment can operate in battery charging mode, battery discharging mode, and idle mode independently of the charger / discharger included in another set of equipment.

[0066] The system control device (100) includes a monitoring circuit (110) and a controller (120).

[0067] The monitoring circuit (110) can individually monitor the status of the converter (Pi-j) and the status of the charger / discharger (Ci-j).

[0068] The monitoring circuit (110) can obtain measurement data of the voltage and current of the DC power input and output to the converter (Pi-j). The monitoring circuit (110) can obtain measurement data of the voltage and current of the DC power input and output to the charger / discharger (Ci-j).

[0069] The controller (120) may be configured to include, in hardware terms, at least one of ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), microprocessors, and other electrical units for performing functions.

[0070] The controller (120) may have a memory built into it. The memory may include at least one type of storage medium among a flash memory type, a hard disk type, an SSD (Solid State Disk type), an SDD (Silicon Disk Drive type), a multimedia card micro type, a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), and a programmable read-only memory (PROM). The memory may store data and a program required for an operation by the controller (120). The memory may store data indicating a result of an operation by the controller (120).

[0071] The memory may have predetermined battery charging rules(s) recorded therein. The battery charging rules may be for determining which of the two or more chargers / dischargers in the battery-off state requires priority battery charging when at least two of the m×n×q chargers / dischargers are in a battery-off state.

[0072] In the memory, the path length from each converter of the ith charge / discharge group (Gi) to each charger / discharger of the ith charge / discharge group (Gi) may be stored in advance. When x and y are different natural numbers less than or equal to n, the path length of the converter (Pi-x) for the charger / discharger (Ci-x) may be shorter than the path length of the converter (Pi-x) for the charger / discharger (Ci-y).

[0073] The controller (120) can monitor the first to mth group status information individually corresponding to the first to mth charge / discharge groups (G1 to Gm) based on the measurement data acquired by the monitoring circuit (110).

[0074] The controller (120) can individually control the operation mode of each converter (Pi-1 to Pi-n) of the equipment set (Ei-1 to Ei-n) included in the i-th charge / discharge group (Gi) so that the load rate of the i-th charge / discharge group (Gi) is within the reference load rate range, based on the status information of the first to m-th groups.

[0075] In the present invention, the fact that the battery group (Gi) operates in a charge-dominant state may mean that the total charging power (which may be referred to as "consumption power") of the battery group (Gi) is equal to or greater than the total discharging power (which may be referred to as "regeneration power"). The fact that the battery group (Gi) operates in a discharge-dominant state may mean that the total discharging power of the battery group (Gi) is greater than the total charging power.

[0076] The total charging power of a battery group (Gi) may represent the sum of the power supplied to the charger / discharger(s) operating in charging mode among the plurality of chargers / dischargers (Ci-1 to Ci-n) of the battery group (Gi).

[0077] The total discharge power of a battery group (Gi) can represent the sum of the power recovered from the charger / discharger(s) operating in discharge mode among the multiple charger / discharger(s) (Ci-1 to Ci-n) of the battery group (Gi).

[0078] Referring to Fig. 4, an exemplary arrangement form of a total of m×n sets of equipment can be confirmed. The X-axis may indicate a direction corresponding to the ground, and the Y-axis may indicate a direction perpendicular to the ground. In Fig. 4, the charge / discharge groups (G1 to Gm) are arranged to form individual rows, and the equipment sets belonging to the same charge / discharge group are stacked vertically. Of course, a total of m×n sets of equipment may be arranged differently from that illustrated in Fig. 4.

[0079] The controller (120) may, when at least one charger / discharger in each of at least two charge / discharge groups (G1 to Gm) is in a battery non-input state, set any one of the charger / dischargers in the battery non-input state as a top priority battery input target according to a first battery input rule. The first battery input rule may be predetermined to select any one of the charger / dischargers in any one of the charge / discharge groups having the greatest discharge superiority state among the at least two charge / discharge groups. For example, when all of the charge / discharge groups (G1 to Gm) are operating in a charge superiority state, it may be said that any one of the charge / discharge groups (G1 to Gm) has the smallest total charge / discharge power (or its absolute value), which is the difference between the total charge power and the total discharge power. As another example, when two or more charge / discharge groups among the charge / discharge groups (G1 to Gm) are operating in a discharge-dominant state, it can be said that among the two or more charge / discharge groups in the discharge-dominant state, one charge / discharge group with the largest total charge / discharge power has the maximum discharge-dominant state.

[0080] The more severe the discharge-dominant state, the greater the possibility of power recovery, and the greater the possibility of power recovery, the greater the DC-AC power conversion loss may be. The controller (120) may assign the highest battery injection priority to a specific charger / discharger in the charger / discharger group with the greatest discharge-dominant state. Accordingly, the charger / discharger assigned the highest battery injection priority may start the charging / discharging process earlier than other chargers / dischargers in idle mode, and the discharge-dominant state of the charger / discharger group to which the charger / discharger belongs may be alleviated.

[0081] The controller (120) may, if two or more chargers / dischargers (C1-1 to Cm-n) of all chargers / dischargers of the charge / discharge group (G1 to Gm) are in a battery non-input state, set one of the two or more chargers / dischargers in the battery non-input state as a priority battery insertion target according to a second battery insertion rule. The second battery insertion rule may be predetermined to select one charger / discharger that is closest to a predetermined battery receiving point (BA). The battery receiving point (BA) may be a location where a battery tray (BT) containing battery cells that have completed the assembly process is transported.

[0082] The second battery injection rule may be a rule applied to selecting a charger / discharger from a charger / discharger group selected by the first battery injection rule. For example, if two chargers / dischargers (Em-2, Em-3) of the charger / discharger group (Gm) selected by the first battery injection rule are in a non-injected state, among the two chargers / dischargers (Em-2, Em-3), the charger / discharger (Em-2), which is closer to the battery entry point (BA) than the charger / discharger (Em-3), may be set as the top priority battery injection target according to the second battery injection rule. In this case, the stacker crane (SC) may pick up the battery tray (BT) located at the battery entry point (BA) and insert it into the charger / discharger (Em-2). Accordingly, a pair of DC power terminals of the battery tray (BT) are connected to a pair of DC power terminals of the charger / discharger (Em-2).

[0083] When a charger / discharger of a battery charging / discharging system (10) completes a charging / discharging process for a battery tray (BT) provided thereto, the stacker crane (SC) can pick up the battery tray (BT) from the charger / discharger into which the battery tray (BT) for which the charging / discharging process has been completed is inserted and then transport it to a designated battery delivery point (BB).

[0084] Figure 5 is a flowchart schematically illustrating a system control method according to another embodiment of the present invention. The method according to Figure 5 can be repeatedly executed periodically or aperiodically by the system control device (100) while the charging / discharging process is in progress by the battery charging / discharging system (10).

[0085] Referring to FIGS. 1 to 5, in step S510, the controller (120) monitors the first to mth group status information individually corresponding to the first to mth charge / discharge groups (G1 to Gm) based on data collected through the monitoring circuit (110).

[0086] The i-th group status information may indicate the total charging power of the charge / discharge group (Gi), the total discharging power, the load factor, the voltage of the DC power channel (BPi), the power of the DC power channel (BPi), the operation mode of at least one of the converters (Pi-1 to Pi-n), the input / output power of at least one of the converters (Pi-1 to Pi-n), whether a battery of at least one of the chargers / dischargers (Ci-1 to Ci-n) is inserted, the operation mode of at least one of the chargers / dischargers (Ci-1 to Ci-n), the input / output power of at least one of the chargers / dischargers (Ci-1 to Ci-n), etc. For reference, the power of the DC power channel (BPi) may indicate the difference between the total charging power and the total discharging power of the charge / discharge group (Gi).

[0087] In step S520, the controller (120) individually controls the operation mode of each converter of the plurality of equipment sets (Ei-1 to Ei-n) included in each operating charge / discharge group (e.g., Gi) based on the status information of the first to m-th charge / discharge groups (G1 to Gm) such that the load ratio of each operating charge / discharge group (e.g., Gi) falls within a reference load ratio range. That a certain charge / discharge group is operating may mean that at least one converter of the charge / discharge group is in a power supply mode or a power regeneration mode.

[0088] The reference load factor range may be a range of load factors of the converter in which the power conversion efficiency of the converter is equal to or greater than a predetermined appropriate efficiency (e.g., 50%).

[0089] The load factor of a converter can represent the ratio of the input / output power of the converter to the rated power of the converter. If the load factor of the converter is too low or too high, the power conversion efficiency of the converter may be reduced. For example, if the rated power of the converter is 10 kW, the load factor of the converter can be said to be 30% if the input / output power of the converter is +3 kW, and the load factor of the converter can be said to be 50% if the input / output power of the converter is -5 kW. The lower limit (e.g., 35%) and the upper limit (e.g., 70%) of the reference load factor range can be referred to as the first reference load factor and the second reference load factor, respectively.

[0090] The load factor of the ith charge / discharge group (Gi) may be determined to be the same as the supply load factor in a charge-dominant state, and may be determined to be the same as the regenerative load factor in a discharge-dominant state. The supply load factor may represent the ratio of the total charging power of the ith charge / discharge group (Gi) to the total rated power corresponding to the number of converter(s) operating in the power supply mode among the plurality of converters (Pi-1 to Pi-n). The regenerative load factor may represent the ratio of the total discharge power (absolute value) of the ith charge / discharge group (Gi) to the total rated power corresponding to the number of converter(s) operating in the power regenerative mode among the plurality of converters (Pi-1 to Pi-n).

[0091] Alternatively, the load factor of the ith charge / discharge group (Gi) may be expressed as the total charge / discharge power of the ith charge / discharge group (Gi) divided by the logarithm of the converter(s) operating in power supply mode or power regeneration mode among the plurality of converters (Pi-1 to Pi-n). For example, if the rated power of the converter is 10 kW, the total charge / discharge power of the ith charge / discharge group (Gi) is +50 kW, and eight converters (e.g., Pi-1 to Pi-8) of the ith charge / discharge group (Gi) are operating in power supply mode, and two converters (e.g., Pi-11, Pi-12) of the ith charge / discharge group (Gi) are operating in power regeneration mode, then the load factor of the ith charge / discharge group (Gi) is 50 kW / {10 kW*(8+2)} * 100% = 50%. For reference, in this specification, the total charge / discharge power of a charge / discharge group in a charge-dominant state is given a positive sign, and the total charge / discharge power of a charge / discharge group in a discharge-dominant state is given a negative sign. Similarly, the charge power is given a positive sign, and the discharge power is given a negative sign.

[0092] Alternatively, the load factor of the i-th charge / discharge group (Gi) may represent either the supply load factor or the regenerative load factor, whichever has a greater difference from the reference load factor range.

[0093] For example, let us assume that the rated power of the converter is 10 kW, the total charging power of the ith charge / discharge group (Gi) is +60 kW, the total discharging power of the ith charge / discharge group (Gi) is -10 kW, eight converters (e.g., Pi-1 to Pi-8) of the ith charge / discharge group (Gi) are operating in power supply mode, and two converters (e.g., Pi-11 to Pi-12) of the ith charge / discharge group (Gi) are operating in power recovery mode. Then, the supply load ratio of 60kW / (10kW*8)*100% = 75% exceeds the second reference load ratio of 70%, while the regenerative load ratio of 10kW / (10kW*2)*100% is within the reference load ratio range of 35-70%, so the load ratio of the i-th charge / discharge group (Gi) can be determined as 75%, which is the same as the supply load ratio.

[0094] As another example, let's say that the rated power of the converter is 10 kW, the total charging power of the ith charge / discharge group (Gi) is +60 kW, the total discharging power of the ith charge / discharge group (Gi) is -16 kW, eight converters (e.g., Pi-1 to Pi-8) of the ith charge / discharge group (Gi) are operating in power supply mode, and two converters (e.g., Pi-11 to Pi-12) of the ith charge / discharge group (Gi) are operating in power regeneration mode. Then, since the regenerative load factor of 16 kW / (10 kW*2)*100% = 80% has a greater difference from the second reference load factor of 70% than the supply load factor of 60 kW / (10 kW*8)*100% = 75%, the load factor of the ith charge / discharge group (Gi) can be determined as 80%, which is the same as the regenerative load factor.

[0095] FIG. 6 is a flowchart schematically illustrating an example of subroutines that may be included in step S520 of FIG. 5. The method of FIG. 6 may be individually executed for the first to mth charge / discharge groups (G1 to Gm).

[0096] Referring to FIG. 6, in step S610, the controller (120) determines whether the i-th charge / discharge group (Gi) is operating in a charge-dominant state. If the value of step S610 is “Yes,” the controller can proceed to step S620.

[0097] In step S620, the controller (120) determines whether the load rate of the i-th charge / discharge group (Gi) exceeds the upper limit of the reference load rate range (the second reference load rate). If the value of step S620 is “Yes,” the process can proceed to step S630.

[0098] In step S630, the controller (120) selects one converter in the idle mode among the plurality of converters (Pi-1 to Pn) of the i-th charge / discharge group (Gi) as the i-th control target.

[0099] In step S640, the controller (120) switches the operation mode of the i-th control target from the idle mode to the power supply mode.

[0100] Fig. 7 is a flowchart schematically illustrating an example of subroutines that may be included in step S630 of Fig. 6. The method of Fig. 7 may be executed under the condition that at least one charger / discharger among the plurality of chargers / dischargers (Ci-1 to Cn) of the i-th charge / discharge group (Gi) is in battery charging mode, and two or more converters among the plurality of converters (Pi-1 to Pi-n) of the i-th charge / discharge group (Gi) are in idle mode.

[0101] Referring to FIG. 7, in step S710, the controller (120) determines the priority of two or more converters in idle mode.

[0102] The priority of each converter may be determined based on at least one of the total path length and the mode duration of the converter. The mode duration of a converter in idle mode may represent the length of time from the time the converter last entered idle mode to the execution time of step S710.

[0103] The total path length of each converter in idle mode may be related to the charger / discharger(s) in battery charging mode within the i-th charge / discharge group (Gi). Assuming that the converter (Pi-j) is in idle mode, the total path length of the converter (Pi-j) may be the sum of the path lengths from the converter (Pi-j) to each charger / discharger in battery charging mode. For example, suppose that the converter (P1-2) is in idle mode and three chargers / dischargers (C1-3 to C1-5) are in battery charging mode. Then, the total path length of the converter (P1-2) may be determined as equal to the sum of the path length from the converter (P1-2) to the charger / discharger (C1-3), the path length from the converter (P1-2) to the charger / discharger (C1-4), and the path length from the converter (P1-2) to the charger / discharger (C1-5).

[0104] For two or more converters in idle mode, the highest priority can be set based on the shortest total path length.

[0105] Alternatively, for more than one converter in idle mode, the highest priority can be set based on the longest mode duration.

[0106] Alternatively, for two or more converters in idle mode, the priority may be set based on both the total path length and the mode duration, with the highest priority being given to the lowest or highest ranking score. Equations 1 and 2 below are exemplary mathematical operations that may be utilized to calculate the ranking score for each converter.

[0107] <Formula 1>

[0108]

[0109] <Formula 2>

[0110]

[0111] In formulas 1 and 2, A i-jis the rank score of the converter (Pi-j), L i-j is the total path length of the transformer (Pi-j), T i-j is the mode duration of the converter (Pi-j), W1 is a given first coefficient (which may be positive), and W2 is a given second coefficient (which may be positive).

[0112] According to Equation 1, T i-j The bigger the L i-j The shorter the A i-j increases. Therefore, when Equation 1 is used, higher priorities can be given in the order of the ranking score.

[0113] According to Equation 2, T i-j The bigger the L i-j The shorter the A i-j is decreasing. Therefore, when Equation 2 is used, higher priorities can be given in the order of smaller ranking scores.

[0114] In step S720, the controller (120) selects one converter with the highest priority among two or more converters in the idle mode as the i-th control target to be switched to the power supply mode.

[0115] In step S720, the i-th control target selected operates in power supply mode as step S640 is executed. Accordingly, the following three technical effects are provided. The first technical effect is that the load ratio of the i-th charge / discharge group (Gi) becomes within the reference load ratio range or approaches the second reference load ratio. The second technical effect is that the increase in line loss while supplying power to two or more chargers / dischargers in the battery charging mode of the i-th charge / discharge group (Gi) is minimized. The third technical effect is that the imbalance in the operating time in the idle mode among the plurality of converters of the i-th charge / discharge group (Gi) is suppressed. FIG. 8 is a flowchart schematically illustrating another example of subroutines that may be included in step S520 of FIG. 5. The method of FIG. 8 may be individually executed for the first to m-th charge / discharge groups (G1 to Gm).

[0116] Referring to FIG. 8, in step S810, the controller (120) determines whether the i-th charge / discharge group (Gi) is operating in a charge-dominant state. If the value of step S810 is “Yes,” the controller can proceed to step S820.

[0117] In step S820, the controller (120) determines whether the load rate of the i-th charge / discharge group (Gi) falls below the lower limit of the reference load rate range (the first reference load rate). If the value of step S820 is “Yes,” the process can proceed to step S830.

[0118] In step S830, the controller (120) selects one converter in power supply mode among the plurality of converters (Pi-1 to Pn) of the i-th charge / discharge group (Gi) as the i-th control target.

[0119] In step S840, the controller (120) switches the operation mode of the i-th control target from the power supply mode to the idle mode.

[0120] Fig. 9 is a flowchart schematically illustrating an example of subroutines that may be included in step S830 of Fig. 8. The method of Fig. 9 may be executed under the condition that at least one charger / discharger among the plurality of chargers / dischargers (Ci-1 to Cn) of the i-th charge / discharge group (Gi) is in battery charging mode, and two or more converters among the plurality of converters (Pi-1 to Pi-n) of the i-th charge / discharge group (Gi) are in power supply mode.

[0121] Referring to FIG. 9, in step S910, the controller (120) determines the priority of two or more converters in power supply mode.

[0122] The priority of each converter may be determined based on at least one of the total path length and mode duration of the converter. The mode duration of a converter in power supply mode may represent the length of time from the time the converter last entered power supply mode to the execution time of step S910.

[0123] The total path length of each converter in power supply mode may be related to the charger(s) in battery charging mode within the i-th charge / discharge group (Gi). Assuming that the converter (Pi-j) is in power supply mode, the total path length of the converter (Pi-j) may be the sum of the path lengths from the converter (Pi-j) to each charger / discharger in battery charging mode. The method for determining the total path length has already been described with reference to Fig. 7, and thus a repeated description is omitted.

[0124] For two or more converters in power supply mode, a higher priority can be set based on the longest total path length.

[0125] Alternatively, for two or more converters in power supply mode, higher priority may be set in order of longest mode duration.

[0126] Alternatively, for two or more converters in power supply mode, a higher priority may be set based on a ranking score based on both the total path length and the mode duration, with the highest priority being given to the lowest. Equations 3 and 4 below are exemplary mathematical operations that may be utilized to compute the ranking score for each converter.

[0127] <Formula 3>

[0128]

[0129] <Formula 4>

[0130]

[0131] In formulas 3 and 4, B i-j is the rank score of the converter (Pi-j), L i-j is the total path length of the transformer (Pi-j), T i-j is the mode duration of the converter (Pi-j), W3 is a given third coefficient (which may be positive), and W4 is a given fourth coefficient (which may be positive).

[0132] According to Equation 3, T i-j The bigger the L i-j The longer the B i-j increases. Therefore, when Equation 3 is used, higher priorities can be given in the order of the ranking score.

[0133] According to Equation 4, T i-j The bigger the L i-j The longer the B i-j is decreasing. Therefore, when Equation 4 is used, higher priorities can be given in the order of smaller ranking scores.

[0134] In step S920, the controller (120) selects one converter with the highest priority among two or more converters in power supply mode as the i-th control target to be switched to idle mode.

[0135] The i-th control target selected in step S920 operates in the idle mode as step S840 is executed. Accordingly, the following three technical effects are provided. The first technical effect is that the load ratio of the i-th charge / discharge group (Gi) becomes within the reference load ratio range or approaches the first reference load ratio. The second technical effect is that the reduction of line loss during power supply to two or more chargers / dischargers in the battery charging mode of the i-th charge / discharge group (Gi) is maximized. The third technical effect is that the imbalance of operating times in the power supply mode among multiple converters of the i-th charge / discharge group (Gi) is suppressed.

[0136] Fig. 10 is a flowchart schematically illustrating another example of subroutines that may be included in step S520 of Fig. 5. The method of Fig. 10 may be individually executed for the first to mth charge / discharge groups (G1 to Gm).

[0137] Referring to FIG. 10, in step S1010, the controller (120) determines whether the i-th charge / discharge group (Gi) is operating in a discharge-dominant state. If the value of step S1010 is “Yes,” the controller can proceed to step S1020.

[0138] In step S1020, the controller (120) determines whether the load rate of the i-th charge / discharge group (Gi) exceeds the upper limit of the reference load rate range (the second reference load rate). If the value of step S1020 is “Yes,” the process can proceed to step S1030.

[0139] In step S1030, the controller (120) selects one converter in the idle mode among the plurality of converters (Pi-1 to Pn) of the i-th charge / discharge group (Gi) as the i-th control target.

[0140] In step S1040, the controller (120) switches the operation mode of the i-th control target from the idle mode to the power recovery mode.

[0141] Fig. 11 is a flowchart schematically illustrating an example of subroutines that may be included in step S1030 of Fig. 10. The method of Fig. 11 may be executed under the condition that at least one charger / discharger among the plurality of chargers / dischargers (Ci-1 to Cn) of the i-th charge / discharge group (Gi) is in battery discharge mode, and two or more converters among the plurality of converters (Pi-1 to Pi-n) of the i-th charge / discharge group (Gi) are in idle mode.

[0142] Referring to FIG. 11, in step S1110, the controller (120) determines the priority of two or more converters in the idle mode. Similar to what was described above with reference to FIG. 7, in the method according to FIG. 11, the priority of each converter may be determined based on at least one of the total path length and mode duration of the converter.

[0143] The total path length of each converter in idle mode may be related to the charger(s) in battery discharge mode within the i-th charge / discharge group (Gi). Assuming that the converter (Pi-j) is in idle mode, the total path length of the converter (Pi-j) may be the sum of the path lengths from the converter (Pi-j) to each charger / discharger in battery discharge mode. The method for determining the total path length has already been described with reference to Fig. 7, and thus a repeated description is omitted.

[0144] For two or more converters in idle mode, the highest priority can be set based on the shortest total path length.

[0145] Alternatively, for more than one converter in idle mode, the highest priority can be set based on the longest mode duration.

[0146] Alternatively, for two or more converters in idle mode, a higher priority may be set in ascending or descending order of ranking scores based on both total path length and mode duration. In this case, a mathematical operation may be used, such as Equation 1 or Equation 2 described above, in which a predetermined positive or negative correspondence between total path length and ranking score and / or a predetermined positive or negative correspondence between mode duration and ranking score is defined.

[0147] In step S1120, the controller (120) selects one converter with the highest priority among two or more converters in the idle mode as the i-th control target to be switched to the power recovery mode.

[0148] The i-th control target selected in step S1120 operates in power regeneration mode as step S1040 is executed. Accordingly, the following three technical effects are provided. The first technical effect is that the load ratio of the i-th charge / discharge group (Gi) becomes within the reference load ratio range or approaches the second reference load ratio. The second technical effect is that the increase in line loss during power regeneration from two or more chargers / dischargers in the battery discharge mode of the i-th charge / discharge group (Gi) to the AC power grid (1) is minimized. The third technical effect is that the imbalance in operating time in the idle mode among the plurality of converters of the i-th charge / discharge group (Gi) is suppressed.

[0149] Figure 12 is a flowchart schematically illustrating another example of subroutines that may be included in step S520 of Figure 5. The method of Figure 12 may be individually executed for the first to mth charge / discharge groups (G1 to Gm).

[0150] Referring to FIG. 12, in step S1210, the controller (120) determines whether the i-th charge / discharge group (Gi) is operating in a discharge-dominant state. If the value of step S1210 is “Yes,” the process can proceed to step S1220.

[0151] In step S1220, the controller (120) determines whether the load rate of the i-th charge / discharge group (Gi) is lower than the lower limit of the reference load rate range (the first reference load rate). If the value of step S1220 is “Yes,” the process can proceed to step S1230.

[0152] In step S1230, the controller (120) selects one converter in power recovery mode among the plurality of converters (Pi-1 to Pn) of the i-th charge / discharge group (Gi) as the i-th control target.

[0153] In step S1240, the controller (120) switches the operation mode of the i-th control target from the power recovery mode to the idle mode.

[0154] Fig. 13 is a flowchart schematically illustrating an example of subroutines that may be included in step S1230 of Fig. 12. The method of Fig. 13 may be executed under the condition that at least one charger / discharger among the plurality of chargers / dischargers (Ci-1 to Cn) of the i-th charge / discharge group (Gi) is in battery discharge mode, and two or more converters among the plurality of converters (Pi-1 to Pi-n) of the i-th charge / discharge group (Gi) are in power regeneration mode.

[0155] Referring to FIG. 13, in step S1310, the controller (120) determines the priority of two or more converters in power recovery mode. Similar to what was described above with reference to FIG. 9, the priority of each converter may be determined based on at least one of the total path length and mode duration of the converter.

[0156] The total path length of each converter in power regeneration mode may be related to the charger(s) in battery discharge mode within the i-th charge / discharge group (Gi). Assuming that the converter (Pi-j) is in power regeneration mode, the total path length of the converter (Pi-j) may be the sum of the path lengths from the converter (Pi-j) to each charger / discharger in battery discharge mode. The method for determining the total path length has already been described with reference to Fig. 7, and thus a repeated description is omitted.

[0157] For two or more converters in power recovery mode, a higher priority can be set based on the longest total path length.

[0158] Alternatively, for two or more converters in power recovery mode, higher priority may be set in order of longest mode duration.

[0159] Alternatively, for two or more converters in power recovery mode, a higher priority may be set in ascending or descending order of ranking scores based on both total path length and mode duration. In this case, a mathematical operation may be used, such as Equation 3 or Equation 4 described above, in which a predetermined positive or negative correspondence between total path length and ranking score and / or a predetermined positive or negative correspondence between mode duration and ranking score is defined.

[0160] In step S1320, the controller (120) selects one converter with the highest priority among two or more converters in power recovery mode as the i-th control target to be switched to idle mode.

[0161] The i-th control target selected in step S1320 operates in the idle mode as step S1240 is executed. Accordingly, the following three technical effects are provided. The first technical effect is that the load ratio of the i-th charge / discharge group (Gi) becomes within the reference load ratio range or approaches the first reference load ratio. The second technical effect is that the reduction of line loss during power regeneration from two or more chargers / dischargers in the battery discharge mode of the i-th charge / discharge group (Gi) is maximized. The third technical effect is that the imbalance of operating times in the power regeneration mode among the plurality of converters of the i-th charge / discharge group (Gi) is suppressed.

[0162] Fig. 14 is a flowchart schematically illustrating a system control method according to another embodiment of the present invention. The method according to Fig. 14 can be repeatedly executed periodically or aperiodically by the system control device (100) while the charging / discharging process is in progress by the battery charging / discharging system (10).

[0163] Referring to FIG. 14, in step S1410, the controller (120) determines whether at least one of the first to mth charge / discharge groups (G1 to Gm) is in a battery insertion state. If a certain charge / discharge group is in a battery insertion state, it means that at least one charger / discharger of the charge / discharge group is in a battery non-input state. If the value of step S1410 is "Yes", the process can proceed to step S1420. If the value of step S1410 is "No", it means that the battery tray (BT) is already inserted into all the charger / dischargers (C1-1 to Cm-n) of the first to mth charge / discharge groups (G1 to Gm).

[0164] In step S1420, the controller (120) determines whether there are two or more charge / discharge groups in a battery insertion state. If the value of step S1420 is "Yes," the process can proceed to step S1430. If the value of step S1420 is "No," it means that only one of the first to mth charge / discharge groups (G1 to Gm) is in a battery insertion state. If the value of step S1420 is "No," the process can proceed to step S1440.

[0165] In step S1430, the controller (120) selects one of the two or more charge / discharge groups in a battery input state that has the greatest discharge dominance.

[0166] In step S1440, the controller (120) determines whether two or more chargers / dischargers in a single charge / discharge group determined to be in a battery insertion state in step S1420 or in a charge / discharge group selected in step S1430 are in a battery non-input state. If the value of step S1440 is "Yes", the process can proceed to step S1450. If the value of step S1440 is "No", the process can proceed to step S1452.

[0167] In step S1450, the controller (120) sets one of two or more chargers and dischargers that is in a non-charged state and is closest to a predetermined battery input point (BA) as the highest priority battery input target.

[0168] In step S1452, the controller (120) sets a single charger / discharger in a battery non-injection state as the highest priority battery injection target.

[0169] Setting information regarding the priority battery loading target can be transmitted to the stacker crane (SC). Based on the setting information, the stacker crane (SC) can provide a battery tray (BT) waiting at the battery receiving point (BA) to the charger / discharger designated as the priority battery loading target.

[0170] The controller (120) may prohibit the battery charging mode for each of the remaining chargers and dischargers of the i-th charge and discharge group (Gi) when the first adjacent chargers and dischargers among the plurality of chargers and dischargers (Ci-1 to Ci-n) of the i-th charge and discharge group (Gi) are in the battery charging mode. The first number may be expressed as in the following mathematical expression 5.

[0171] <Formula 5>

[0172]

[0173] In Equation 5, I P_i is the maximum allowable current of the DC power channel (BPi), I char_max is the maximum current supplied to the charger / discharger from the DC power channel (BPi) during the charging / discharging process, and N1 represents the first logarithm. [] is the Gaussian symbol. For example, I P_i = 5000 A, I char_max = 1500 A, then N1 = 3. Meanwhile, the highest priority battery input target set in the method according to Fig. 14 may be a charger / discharger in which the battery charging mode is not prohibited.

[0174] The controller (120) may prohibit the battery discharge mode for each of the remaining chargers and dischargers of the i-th charge and discharge group (Gi), when the second number of chargers and dischargers (Ci-1 to Ci-n) of the i-th charge and discharge group (Gi) are in the battery discharge mode. The second number may be expressed as in Equation 6 below.

[0175] <Formula 6>

[0176]

[0177] In Equation 6, I dchar_max is the maximum current supplied from the charger to the DC power channel (BPi) while the charger is performing the charging / discharging process, and N2 represents the second logarithm. For example, I P_i = 5000 A, I dchar_max If = 2000 A, then N2 = 2. I in Equation 6 P_i is I of formula 5 P_i It can be like this.

[0178] FIG. 15 is a drawing referenced for explaining the circuit configuration and function of the main smoothing circuit and sub smoothing circuit shown in FIG. 1.

[0179] Referring to FIG. 15, the charging / discharging equipment (Ei) may further include at least one of a main smoothing circuit (HAi-j) and a sub smoothing circuit (HBi-j).

[0180] A main smoothing circuit (HAi-j) is installed in an electrical region between a pair of DC power terminals of a converter (Pi-j) and two nodes (NAi,NBi) of a DC power channel (BPi). The main smoothing circuit (HAi-j) includes a capacitor (CMi-j), a resistor (RMi-j), and a switch (SMi-j). The capacitor (CMi-j) can be connected between a pair of DC power terminals of the converter (Pi-j). The resistor (RMi-j) can be connected between the DC power terminal (+) of the converter (Pi-j) and the node (NAi). The switch (SMi-j) can be connected in parallel with the resistor (RMi-j).

[0181] The controller (120) can control the switch (SMi-j) to be in the off state while the converter (Pi-j) is in the idle mode.

[0182] When the converter (Pi-j) is switched from the idle mode to the power supply mode or the power recovery mode, the controller (120) can check the voltage difference between a pair of DC power terminals of the converter (Pi-j) and the voltage between two nodes (NAi, NBi), and if the voltage difference is less than a predetermined threshold voltage, control the switch (SMi-j) to be turned on.

[0183] A sub-smoothing circuit (HBi-j) is installed in an electrical region between two nodes (NAi, NBi) of a DC power channel (BPi) and a pair of DC power terminals of a charger / discharger (Ci-j). The sub-smoothing circuit (HBi-j) includes a capacitor (CSi-j), a resistor (RSi-j), and a switch (SSi-j). The capacitor (CSi-j) can be connected between a pair of DC power terminals of the charger / discharger (Ci-j). The resistor (RSi-j) can be connected between the DC power terminal (+) of the charger / discharger (Ci-j) and the node (NAi). The switch (SSi-j) can be connected in parallel with the resistor (RSi-j).

[0184] The controller (120) can control the switch (SSi-j) to be in the off state while the charger / discharger (Ci-j) is in the idle mode (battery not inserted).

[0185] When the charger / discharger (Ci-j) is switched from the idle mode to the battery charging mode or the battery discharging mode, the controller (120) checks the voltage difference between a pair of DC power terminals of the charger / discharger (Ci-j) and the voltage between two nodes (NAi, NBi), and if the voltage difference is less than the threshold voltage, the controller (120) can control the switch (SSi-j) to be turned on.

[0186] The embodiments of the present invention described above are not implemented only through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded, and such implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

[0187] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0188] In addition, the present invention described above is not limited to the above-described embodiments and the attached drawings, and all or part of each embodiment may be selectively combined and configured so that various modifications can be made, as those skilled in the art can make various substitutions, modifications, and changes within the scope of the technical idea of ​​the present invention.

Claims

1. A system control device for a battery charging / discharging system including first to mth charge / discharge groups, each charge / discharge group including a plurality of sets of equipment connected via a DC power channel, and each set of equipment including a converter and a charger / discharger, A controller configured to monitor the status information of the first to mth group of the first to mth charge / discharge groups, The above controller, A system control device configured to control the operation mode of each converter of the plurality of equipment sets included in each operating charge / discharge group by comparing the load rate of each operating charge / discharge group among the first to m charge / discharge groups with a reference load rate range based on the status information of the first to m group, wherein m is a natural number greater than or equal to 2.

2. In paragraph 1, The above controller, A system control device configured to switch one converter of the i-th charge / discharge group from an idle mode to a power supply mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a charge-dominant state and the load rate of the i-th charge / discharge group exceeds the upper limit of the reference load rate range, wherein i is a natural number less than or equal to m.

3. In paragraph 2, The above controller, A system control device configured to determine the priority of two or more converters in the idle mode among a plurality of chargers and dischargers of the i-th charge / discharge group when the load rate of the i-th charge / discharge group exceeds the upper limit of the reference load rate range while the i-th charge / discharge group is operating in a charge-dominant state, and to switch one converter with the highest priority among the two or more converters in the idle mode to the power supply mode.

4. In paragraph 1, The above controller, A system control device configured to switch one converter of the i-th charge / discharge group from a power supply mode to an idle mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a charge-dominant state and the load rate of the i-th charge / discharge group falls below the lower limit of the reference load rate range, wherein i is a natural number less than or equal to m.

5. In paragraph 4, The above controller, A system control device configured to determine the priority of two or more converters in a power supply mode among a plurality of chargers and dischargers of the i-th charge / discharge group when the load rate of the i-th charge / discharge group falls below the lower limit of the reference load rate range while the i-th charge / discharge group is operating in a charge-dominant state, and to switch one converter with the highest priority among the two or more converters in the power supply mode to the idle mode.

6. In paragraph 1, The above controller, A system control device configured to switch one converter of the i-th charge / discharge group from an idle mode to a power recovery mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a discharge-dominant state and the load ratio of the i-th charge / discharge group exceeds the upper limit of the reference load ratio range, wherein i is a natural number less than or equal to m.

7. In paragraph 6, The above controller, A system control device configured to determine the priority of two or more converters in the idle mode among the plurality of chargers and dischargers of the i-th charge / discharge group when the load ratio of the i-th charge / discharge group exceeds the upper limit of the reference load ratio range while the i-th charge / discharge group is operating in a discharge-dominant state, and to switch one converter with the highest priority among the two or more converters in the idle mode to the power regeneration mode.

8. In paragraph 1, The above controller, A system control device configured to switch one converter of the i-th charge / discharge group from a power recovery mode to an idle mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a discharge-dominant state and the load ratio of the i-th charge / discharge group falls below the lower limit of the reference load ratio range, wherein i is a natural number less than or equal to m.

9. In paragraph 8, The above controller, A system control device configured to determine the priority of two or more converters in the power regeneration mode among the plurality of chargers and dischargers of the i-th charge / discharge group when the load ratio of the i-th charge / discharge group falls below the lower limit of the reference load ratio range while the i-th charge / discharge group is operating in a discharge-dominant state, and to switch one converter with the highest priority among the two or more converters in the power regeneration mode to the idle mode.

10. In paragraph 1, The above controller, A system control device that, when two or more of the first to mth charge / discharge groups are in a battery-input state, selects one charge / discharge group having the greatest discharge superiority state among the two or more charge / discharge groups in the battery-input state, and sets one of the multiple chargers / dischargers in the selected charge / discharge group in a battery-non-input state as the highest priority battery input target.

11. In paragraph 10, The above controller, A system control device that sets, when at least two chargers and dischargers of a charging and discharging group having the maximum discharge dominant state are in the battery non-input state, one of the two or more chargers and dischargers in the battery non-input state that is closest to a predetermined battery input point as the priority battery input target.

12. In paragraph 1, The above controller, When the first number of chargers and dischargers adjacent to each other among the plurality of chargers and dischargers of the i-th charge and discharge group among the first to m-th charge and discharge groups are in the battery charging mode, the battery charging mode is prohibited for each of the remaining chargers and dischargers of the i-th charge and discharge group, A system control device configured to prohibit the battery discharge mode for each of the remaining chargers and dischargers in the i-th charge and discharge group when the second number of chargers and dischargers adjacent to each other among the plurality of chargers and dischargers in the i-th charge and discharge group are in the battery discharge mode, wherein i is a natural number less than or equal to m.

13. A system control method for a battery charging / discharging system comprising first to mth charging / discharging groups, wherein each charging / discharging group comprises a plurality of sets of equipment connected via a DC power channel, and each set of equipment comprises a converter and a charger / discharger. A step of monitoring the status information of the first to mth group of the first to mth charge / discharge groups; and A step of comparing the load ratio of each operating charge / discharge group among the first to m-th charge / discharge groups with a reference load ratio range based on the status information of the first to m-th groups, and controlling the operation mode of each converter of the plurality of equipment sets included in each operating charge / discharge group; A system control method, wherein m is a natural number greater than or equal to 2.

14. In paragraph 13, The step of controlling the operation mode of each converter of the plurality of equipment sets included in each of the above-described operating charge / discharge groups is as follows: A step of switching one converter of the i-th charge / discharge group from an idle mode to a power supply mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a charge-dominant state and the load ratio of the i-th charge / discharge group exceeds the upper limit of the reference load ratio range; A system control method, wherein i is a natural number less than or equal to m.

15. In paragraph 13, The step of controlling the operation mode of each converter of the plurality of equipment sets included in each of the above-described operating charge / discharge groups is as follows: A step of switching one converter of the i-th charge / discharge group from a power supply mode to an idle mode when the i-th charge / discharge group among the first to m-th charge / discharge groups is operating in a charge-dominant state and the load ratio of the i-th charge / discharge group falls below the lower limit of the reference load ratio range; A system control method, wherein i is a natural number less than or equal to m.

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