Converter performing DC-DC conversion and method for controlling same

Abstract

The present invention relates to a DC-DC converter located between a series of batteries and a power conversion system, and includes a primary coil connected to a plurality of battery sources; a secondary coil connected to a load through an output switch set, and the primary coil can be connected to the plurality of battery sources through a plurality of switch sets corresponding to the plurality of battery sources. This allows the size of the converter to be reduced, thereby reducing costs and increasing DC-DC efficiency.

Description

[Technical field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2021-0062341, filed with the Korean Intellectual Property Office on May 14, 2021, and all of the contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a converter that performs DC-DC conversion, and more particularly to a converter that performs DC-DC conversion and is located between a series of batteries and a power conversion system, and a method for controlling the converter. [Background technology]

[0003] An energy storage system is a system that connects new renewable energy, batteries that store power, and existing grid power. In recent years, smart grids and new renewable energy have become more widespread, and as the efficiency and stability of the power system are emphasized, the demand for energy storage systems is increasing to regulate power supply and demand and improve power quality. Depending on the purpose of use, the output and capacity of the energy storage system vary. To configure a large-capacity energy storage system, multiple battery systems can be connected to each other.

[0004] The energy storage system may include a battery section consisting of a number of batteries, a battery management system (BMS) for battery management, a power conversion system (PCS), an energy management system (EMS), a DC-DC converter, etc.

[0005] Among these, in a DC-DC converter that performs DC-DC conversion between a battery and a power conversion system, the design of the transformer is closely related to the cost, efficiency, size, etc. of the entire system. Generally, a DC-DC converter having multiple input sources has a structure in which a coil is assigned to each source. In particular, when the input source is a battery, each input terminal is insulated for safety reasons. However, as the capacity of the battery and the capacity of the DC-DC converter increase, such a transformer structure becomes a negative factor in the efficiency and size of the product, so design improvement is required. Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE PRESENT EMBODIMENT In order to solve the above problems, an object of the present invention is to provide a DC-DC converter having one primary coil for multiple battery sources.

[0007] Another object of the present invention to solve the above problems is to provide a method for controlling a DC-DC converter having one primary coil for multiple battery sources.

[0008] Another object of the present invention to solve the above problems is to provide a power storage device. [Means for solving the problem]

[0009] To achieve the above object, a DC-DC converter according to one embodiment of the present invention includes a primary coil located between a series of batteries and a power conversion system, connected to a plurality of battery sources; and a secondary coil connected to a load via an output switch set, and the primary coil can be connected to the plurality of battery sources via a plurality of switch sets corresponding to the plurality of battery sources.

[0010] Here, the operation of the plurality of switch sets is controlled by the control of a controller connected to the converter, so that the output of only one of the plurality of battery sources can be transmitted to the primary coil.

[0011] In this case, each battery source may be a battery pack, a battery rack, a battery unit, or a battery cell, and the load may include the power conversion system.

[0012] The converter may perform DC-DC conversion during one time period using an active switch set among a plurality of switch sets corresponding to the plurality of battery sources and an output switch set connected to the load.

[0013] In a charging mode, the converter can convert the power output from the power conversion system to a voltage level required by the battery, and in a discharging mode, the converter can convert the output from a battery connected to one active switch set to a DC link voltage that is a voltage level required by the power conversion system.

[0014] To achieve the above-mentioned another object, a converter control method according to one embodiment of the present invention is a method for controlling a converter located between a series of batteries and a power conversion system by a controller interlocking with the converter, and includes the steps of: determining a battery source that operates during a corresponding time period among a plurality of battery sources connected to the converter; activating a switch set corresponding to the operating battery source and deactivating a switch set corresponding to battery sources other than the operating battery source; and controlling the converter to perform DC-DC conversion.

[0015] The step of activating a switch set corresponding to the operating battery source and deactivating a switch set corresponding to a battery source other than the operating battery source may include a step of controlling so that only the output of the switch set corresponding to the operating battery source is transmitted to the primary coil.

[0016] In this case, each battery source may be a battery pack, a battery rack, a battery unit, or a battery cell, and the load may include the power conversion system.

[0017] The step of controlling the converter to perform DC-DC conversion may include a step of controlling the converter to perform DC-DC conversion during one time period using an active switch set among a plurality of switch sets corresponding to the plurality of battery sources and an output switch set connected to the load.

[0018] The step of controlling the converter to perform DC-DC conversion may include controlling the converter to convert power output from the power conversion system to a voltage level required by a battery in a charging mode.

[0019] The step of controlling the converter to perform DC-DC conversion may include controlling the converter in a discharge mode to convert an output from a battery connected to one of the operating switch sets to a DC link voltage that is at a voltage level required for the power conversion system.

[0020] In order to achieve the above-mentioned still another object, a power storage device according to one embodiment of the present invention may include: a DC-DC converter including a plurality of battery sources; a single primary coil connected to the plurality of battery sources and a secondary coil connected to a load; and a controller that controls the DC-DC converter so that the single primary coil transfers power from one of the plurality of battery sources to the load.

[0021] Here, the DC-DC converter includes a plurality of switch sets respectively connected to the plurality of battery sources, and only one of the plurality of switch sets can be activated in one time period under the control of the controller. Effect of the Invention

[0022] According to the above-described embodiments of the present invention, the size of the transformer in the converter and therefore the size of the converter can be reduced compared to existing DC-DC converters, thereby reducing costs and increasing DC-DC efficiency.

[0023] Additionally, the safety function previously achieved through isolation can now be achieved through switching between battery sources using operational control over a set of switches. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a block diagram of a typical energy storage system having individual DC-DC converters for each battery rack. [Diagram 2] FIG. 1 is a schematic circuit diagram of a typical DC-DC converter. [Diagram 3] FIG. 1 is a schematic circuit diagram of a conventional DC-DC converter having multiple input sources. [Figure 4] 1 is a schematic configuration diagram of a power storage device according to an embodiment of the present invention. [Diagram 5] 2 is a conceptual diagram showing a switching operation of the DC-DC converter according to the embodiment of the present invention. FIG. [Figure 6] 1 is a block diagram of an ESS system to which a DC-DC converter according to an embodiment of the present invention is applied. [Figure 7] FIG. 4 is an operational flow diagram of a method for controlling a DC-DC converter according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Since the present invention can be modified in various ways and has various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, it is understood that this is not intended to limit the present invention to the specific embodiment, but includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. Similar reference numerals are used for similar components while describing each drawing.

[0026] Terms such as first, second, A, B, etc. may be used to describe various components, but the components should not be limited by these terms. The terms are used only to distinguish one component from another. For example, a first component may be named a second component, and similarly, a second component may be named a first component, without departing from the scope of the present invention. The term "and / or" includes a combination of multiple associated listed items or any of multiple associated listed items.

[0027] When a component is referred to as being "coupled" or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. In contrast, when a component is referred to as being "directly coupled" or "directly connected" to another component, it should be understood that there are no other components in between.

[0028] The terms used in this application are merely used to describe certain embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, the terms "include" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and are not intended to preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0029] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined in this application.

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0031] FIG. 1 is a block diagram of a typical energy storage system with individual DC-DC converters for each battery rack.

[0032] A battery that serves to store power in an energy storage system may be realized in the form of a battery rack made up of a number of battery modules, and a battery bank made up of a number of battery racks 11-1, 11-2, ..., 11-n. Here, the battery rack may be called a battery pack depending on the device or system in which the battery is used.

[0033] At this time, a battery management system (BMS) may be provided in each of the battery modules, the battery racks, and the battery banks. Referring to FIG. 1, each of the RBMS (Rack BMS) 12-1, 12-2, ..., 12-n manages each battery rack, and the BBMS (Bank BMS) 10 may control the entire battery bank including these battery racks. At this time, the BBMS 10 may serve to monitor the current, voltage, and temperature from the battery bank, calculate the SOC (Status Of Charge) based on the monitoring result, and control charging and discharging. Also, each of the RBMS 12-1, 12-2, ..., 12-n may serve to monitor the current, voltage, and temperature from each battery rack, calculate the SOC based on the monitoring result, and control charging and discharging.

[0034] Each battery section, which is made up of a number of batteries and peripheral circuits, devices, etc., is provided with a Battery Section Controller (BSC) 20, which can monitor and control control targets such as voltage, current, temperature, circuit breakers, etc.

[0035] In addition, a power conversion system (PCS) 40 provided for each battery section controls power supplied from the outside and power supplied from the battery section to the outside, controls charging and discharging of the battery, and may include a DC / AC inverter. An energy management system (EMS) 20 connected to the PCS can control the output of the PCS based on the monitoring and control results of the BMS or BSC.

[0036] In the energy storage system of Fig. 1, battery rack 1 (11-1) is connected to DC-DC converter #1 (12-1), battery rack 2 (11-2) is connected to DC-DC converter #2, and battery rack n (11-n) is connected to DC-DC #n (12-n). That is, one corresponding DC-DC converter is used for each battery rack. The outputs of the DC-DC converters corresponding to each battery rack are combined through a DC switchgear & protector and connected to the PCS 40.

[0037] Here, in the discharge mode, the DC-DC converter converts the power stored in the battery into a voltage level required by the PCS 40, i.e., a DC link voltage, and outputs the converted power. Meanwhile, in the charge mode, the DC-DC converter converts the power output from the PCS 40 into a voltage level required by the battery, i.e., a charging voltage.

[0038] On the other hand, communication can be performed between the RBMS 12-1, 12-2, . . . , 12-n, BBMS 10, BSC 20, EMS 30, and PCS controller using a controller area network (CAN) or Ethernet.

[0039] FIG. 2 is a schematic circuit diagram of a typical DC-DC converter.

[0040] The DC-DC converter may be a bidirectional converter, and when conversion is performed in the direction from the battery to the load, the input of the DC-DC converter can be connected to the battery (battery unit, battery rack or battery pack) and the output of the DC-DC converter can be connected to the load.

[0041] The converter shown in Fig. 2 is an example of a full-bridge converter. In the converter shown in Fig. 2, the input end includes a capacitor, an input switching set 58, and a primary coil 51, and the output end includes a secondary coil 52, an output switching set 59, and a capacitor.

[0042] FIG. 3 is a schematic circuit diagram of a typical DC-DC converter having multiple input sources.

[0043] The converter shown in Fig. 3 is also an example of a full-bridge converter, and shows an example in which three battery sources are connected to the input terminal. The converter 60 shown in Fig. 3 includes a capacitor, an input switch set (switch set 1, switch set 2, ..., switch set n), and a primary coil (51-1, 51-2, 51-3) for each battery source. That is, the input switch set and the primary coil corresponding to the battery 1, the battery 2, and the battery 3 are assigned and used. In this case, each input terminal is usually insulated for safety reasons.

[0044] However, the output terminal includes a secondary coil 52, a common output switch set, and a capacitor.

[0045] As can be seen from the examples of Figures 2 and 3, a separate converter is used for each individual battery source (e.g., battery pack, battery rack, battery cell) (as shown in the example of Figure 2), or even if one converter is used for multiple battery units, a separate primary coil is used for each battery source within that converter. That is, in both cases, a separate primary coil is used for each battery source, and multiple primary coils are used for multiple battery sources.

[0046] In such a multi-coil transformer, multiple coils are arranged on the primary side, and as the capacity of the DC-DC converter increases, the wires become thicker, which makes it difficult to design the transformer. In other words, the efficiency of the product decreases, the size increases, and the cost increases, which are negative aspects.

[0047] FIG. 4 is a schematic diagram of a power storage device according to an embodiment of the present invention.

[0048] The power storage device according to an embodiment of the present invention may include a plurality of battery sources; a DC-DC converter 300 including a single primary coil connected to the plurality of battery sources and a secondary coil connected to a load; and a controller 400 for controlling the DC-DC converter so that the primary coil transfers power from one of the plurality of battery sources to the load.

[0049] Here, the DC-DC converter may include a plurality of switch sets respectively connected to the plurality of battery sources, and only one of the plurality of switch sets may be activated in one time period under the control of the controller.

[0050] The DC-DC converter to which the present invention is applied may be a bidirectional converter, and when conversion is performed in the direction from the battery to the load, the input of the DC-DC converter may be connected to the battery (battery unit, battery rack, or battery pack), and the output of the DC-DC converter may be connected to the load. For convenience of explanation in this specification, the left side of FIG. 4, i.e., the battery side, will be called the input or primary side, and the right side, i.e., the load side, will be called the output or secondary side. However, when charging from the load to the battery, the input and output may be described in reverse compared to when discharging from the battery to the load, and in this case, the related explanation should also be understood in reverse.

[0051] As an example of a DC-DC converter to which the present invention can be applied, in addition to a full-bridge converter, other types of converters such as a half-bridge converter and a flyback converter may be used. Although they differ from a full-bridge converter in terms of detailed configuration of an internal circuit, they are the same in that they include a primary coil and a secondary coil as a full-bridge converter, and a switch set or circuit connected to each coil.

[0052] FIG. 4 shows an embodiment of the converter 300 according to the present invention as a full-bridge converter. In the present invention, a converter with multiple or many battery sources as input is considered. Referring to FIG. 4, the DC-DC converter according to an embodiment of the present invention is a converter located between a series of batteries (battery 1, battery 2, ... battery n) and a power conversion system, and performs DC-DC conversion. It can have a series of batteries as multiple inputs and one output connected to a load. Each battery can be connected to a separate switch set, with battery 1 being connected to switch set 1 311, battery 2 being connected to switch set 2 312, and battery n being connected to switch set n 313.

[0053] In the present invention, switch set 1, switch set 2, and switch set n are all connected to one primary coil 330. That is, the DC-DC converter according to the present invention has a single primary coil, although there are multiple battery sources as input. Therefore, in the transformer structure as shown in Fig. 4, there is one coil (330) on the primary side and one coil (350) on the secondary side. Meanwhile, the secondary coil 350 can be connected to a load through a common switch set 350 at the output end.

[0054] That is, a DC-DC converter according to an embodiment of the present invention includes a primary coil connected to a plurality of battery sources and a secondary coil connected to a load through an output switch set, and the primary coil can be connected to the plurality of battery sources through a plurality of switch sets corresponding to the plurality of battery sources, where each battery source can be a battery pack, a battery rack, a battery unit, or a battery cell.

[0055] In addition, a converter according to another embodiment of the present invention may include a primary coil connected to a plurality of battery sources; a plurality of switch sets connected to the plurality of battery sources, respectively, and connected to the primary coil; and a secondary coil connected to a load through an output switch set.

[0056] In the DC-DC converter structure according to the present invention, operation control is required to prevent power circulation between multiple battery sources, and switching operation control for realizing this can be performed by the controller 400 connected to the DC-DC converter 300. The controller 400 linked to the DC-DC converter controls switching for each battery source. In other words, the controller 400 is connected to an input switch set corresponding to each battery source and controls the switching operation of each input switch set.

[0057] FIG. 5 is a conceptual diagram of a switching operation of a DC-DC converter according to an embodiment of the present invention.

[0058] The graph in Figure 5 shows the operating time intervals for each switch set. There is one common switch set at the output end of the converter, and the common switch set at the output end always operates together with any battery source operating at the input end, allowing the corresponding battery source to perform a charge / discharge operation.

[0059] At the input end, when battery 1 is operating, only switch set 1 operates, and the input switching circuits of battery 2 and battery 3 are controlled by the controller to stop operating. Also, when battery 2 is operating, only switch set 2 operates, and switch sets 1 and 3 are controlled by the controller to stop operating. Here, the operation of a switch set means that high-speed switching is performed to DC-DC convert the power from the battery source connected to the corresponding switch set.

[0060] As a result, the DC-DC converter according to an embodiment of the present invention can perform DC-DC conversion during one time period using one operating switch set among multiple switch sets corresponding to multiple battery sources and an output switch set connected to the load.

[0061] In a charging mode, the DC-DC converter can convert the power output from the power conversion system to a voltage level required by a battery, and in a discharging mode, the DC-DC converter can convert the output from a battery connected to an active set of switches to a DC link voltage that is at the voltage level required by the power conversion system.

[0062] FIG. 6 is a block diagram of an ESS system to which a DC-DC converter according to an embodiment of the present invention is applied.

[0063] FIG. 6 shows an example of an ESS (Energy Storage System) system that uses a battery pack made from recycled used batteries, as an example of a system to which a DC-DC converter according to the present invention is applied.

[0064] Referring to FIG. 6, the output of the DC-DC converter 300 is connected to the PCS 600, and the PCS is connected to a grid. The example of FIG. 6 shows a structure in which four battery packs constitute one mini-bank, and a plurality of mini-banks are gathered together to form one battery bank. Each of the PBMSs (PBMS #1-1, PBMS #1-2, PBMS #1-3, PBMS #1-4) manages and controls each battery pack (pack #1-1, pack #1-2, pack #1-3, pack #1-4), and the interface BMS 410 can manage and control a plurality of battery packs included in one mini-bank. In addition, a plurality of interface BMSs that control each mini-bank are connected to a BBMS (Bank BMS), and the BBMS can control the battery bank as a whole and control the output of each DC-DC converter.

[0065] At this time, the PBMS, interface BMS410, and BBMS100 can each monitor the current, voltage, and temperature from the battery bank, mini bank, and battery pack, and calculate the battery's SOC (Status Of Charge) based on the monitoring results to control charging and discharging.

[0066] An energy management system (EMS) 200 controls the output of the PCS 600 based on the monitoring and control results of the BMS, and generally controls and manages the ESS system.

[0067] A power conversion system (PCS) 600 may be a DC / AC inverter that controls the power supplied from the outside and the power supplied from the battery section to the outside, and controls charging and discharging of the battery.

[0068] The DC / AC inverter may be a bidirectional inverter, and in a discharging mode, converts a DC link voltage output from the battery into an AC voltage of the grid and outputs the converted voltage. In a charging mode, the DC / AC inverter may also rectify the AC voltage of the grid, convert it into a DC link voltage, and output the DC link voltage in order to store the grid power in the battery.

[0069] The DC / AC inverter may include a filter for removing harmonics from the AC voltage output to the grid, a phase-locked loop (PLL) for synchronizing the phase of the AC voltage output with the phase of the AC voltage of the grid, etc. The DC / AC inverter may also perform functions such as limiting the voltage fluctuation range, improving the power factor, and removing the DC component.

[0070] In the energy storage system of Fig. 6, battery packs #1-1, #1-2, #1-3, and #1-4 are connected to DC-DC converter #1 300. That is, a plurality of battery packs are connected to one DC-DC converter, and the corresponding DC-DC converter transmits only the output from one battery pack to the PCS 600 through switching between the plurality of battery packs. Similarly, battery packs #2-1, #2-2, #2-3, and #2-4 can be connected to DC-DC converter #2, and battery packs #n-1, #n-2, #n-3, and #n-4 can be connected to DC-DC converter #n.

[0071] For example, in the case of existing technologies, a separate DC-DC converter is used for each 20 kW battery pack, or the transformer in the DC-DC converter requires multiple coils. In contrast, according to the present invention, multiple battery packs can be connected and used with one 20 kW DC-DC converter, and the DC-DC converter according to the embodiment of the present invention has a structure in which one coil is used on the primary side and one coil is used on the secondary side.

[0072] Here, in order to prevent simultaneous operation of battery packs in a mini-bank managed by one DC-DC converter 300, switching control can be performed on input switch circuits connected to each battery pack in the DC-DC converter 300. The switching operation between each battery pack can be performed by the DC-DC converter controller 420, or by the interface BMS 410, or by the DC-DC converter controller 420 and the interface BMS 410. In FIG. 6, the DC-DC converter controller 420 and the interface BMS 410 are shown as separate components, but depending on the implementation, they can be integrated into one software or hardware configuration.

[0073] The outputs of the DC-DC converters are combined through a DC switchgear & protector and connected to the PCS 600. Referring to Fig. 6, multiple DC-DC converters (DC-DC converter #1, ..., DC-DC converter #n) can operate simultaneously, and assuming that five converters operate simultaneously, the total output is 100kW, which can be the capacity of the PCS 600 connected to the converters.

[0074] Here, in the discharge mode, the DC-DC converter converts the power stored in the battery 30 into a voltage level required by the PCS 600, i.e., a DC link voltage, and outputs the converted power. Meanwhile, in the charge mode, the DC-DC converter can convert the power output from the PCS 600 into a voltage level required by the battery, i.e., a charging voltage.

[0075] Meanwhile, communication can be performed between the PBMS, the interface BMS 410, the BBMS 100, the EMS 200, and the PCS controller using CAN or Ethernet.

[0076] FIG. 7 is an operational flow diagram of a method for controlling a DC-DC converter according to an embodiment of the present invention.

[0077] The method of controlling a DC-DC converter according to a preferred embodiment of the present invention may be performed by a controller 400 that cooperates with the DC-DC converter. Here, the controller 400 may be the DC-DC converter controller 420 described in the embodiment of Fig. 6. The controller may also include a part of the DC-DC converter controller and a part of the interface BMS, but the converter controller and the interface BMS may also be realized in an integrated form.

[0078] The controller first determines which battery source among a plurality of battery sources is to be operated during a corresponding time period (S710), activates a switch set corresponding to the operating battery source, and deactivates switch sets corresponding to battery sources other than the operating battery source (S720). That is, only the output of the switch set corresponding to the operating battery source is controlled to be transmitted to the primary coil.

[0079] Thereafter, the controller controls the DC-DC converter to perform DC-DC conversion using the activated switch set, the primary coil, the secondary coil, and the common switch set (S730). In this case, the DC-DC conversion may be performed in the form of converting the power stored in the battery to a voltage level required by the PCS, i.e., the DC link voltage, in the case of a discharging mode. Meanwhile, the DC-DC conversion in the charge mode may be performed in the form of converting the power output from the PCS to a voltage level required by the battery, i.e., the charging voltage.

[0080] It is checked whether the DC-DC conversion should be terminated due to the end of charging or discharging (S740), and the procedure continues. If the operating battery is changed (e.g., S750), the procedure returns to step S720, where the corresponding switch set is activated due to the change in the operating battery, and the remaining switch sets are deactivated again, and the DC-DC conversion procedure is performed.

[0081] If the operating battery is not changed (No in S750), DC-DC conversion can be continued using the activated switch set, the primary coil and the secondary coil, and the common switch set.

[0082] In this manner, the present invention can realize the safety function previously ensured through isolation by switching between battery sources using operational control over the input switch set of multiple battery sources.

[0083] The operation of the method according to the embodiment of the present invention can be realized as a computer readable program or code in a computer readable recording medium. The computer readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. In addition, the computer readable recording medium can be distributed to computer systems connected via a network, and the computer readable program or code can be stored and executed in a distributed manner.

[0084] Additionally, the computer readable recording medium may include a hardware device specially configured to store and execute program instructions, such as a ROM, a RAM, a flash memory, etc. The program instructions may include not only machine code, such as produced by a compiler, but also high-level language code that can be executed by a computer using an interpreter, etc.

[0085] Some aspects of the invention have been described in the context of an apparatus, but it may also be presented in terms of a corresponding method, where 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 be presented in terms of a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware apparatus, 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.

[0086] Although the present invention has been described with reference to preferred embodiments thereof, those skilled in the art will understand that various modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention as set forth in the following claims. [Explanation of symbols]

[0087] 100:BMS 200: EMS 300: DC-DC converter 311, 312, 313: Switch set 330: Primary coil 350: Secondary coil 400: Controller 410: Interface BMS 420: DC-DC controller

Claims

1. A converter is disposed between N battery sources and a load, connected to a controller, and performs DC-DC conversion, One primary coil, and a secondary coil connected to the load through an output switch set; Including, The one primary coil is connected to the N battery sources through N switch sets, and an n-th switch set among the N switch sets is connected to an n-th battery source among the N battery sources, where N is an integer equal to or greater than 2, and n is from 1 to N; By controlling the controller, an output of one of the N battery sources is transmitted to the one primary coil using one switch set that is activated and in operation among the N switch sets; The load includes a power conversion system. converter.

2. The converter comprises:

2. The converter according to claim 1, wherein during one time period, DC-DC conversion is performed using one active switch set among the N switch sets and an output switch set connected to the load.

3. 2. The converter of claim 1, wherein in a charging mode, the converter operates as a bi-directional converter, the operation of which is controlled by the controller using one of the N switch sets that is activated and operational to convert power output from the power conversion system to voltage levels required by the N battery sources.

4. 2. The converter of claim 1, wherein in a discharge mode, the converter converts an output from one of the N battery sources connected to an active switch set to a DC link voltage that is at a voltage level required for the power conversion system.

5. 1. A method of controlling a converter located between N battery sources and a load by a controller associated with the converter, the method comprising the steps of: determining one battery source that operates during a corresponding time period among the N battery sources connected to the converter; activating a switch set corresponding to the one battery source to transmit an output of the one battery source to one primary coil, and deactivating switch sets corresponding to the remaining battery sources other than the one battery source among the N battery sources to cut off the outputs of the remaining battery sources from the one primary coil; and controlling the converter to perform DC-DC conversion using an activated and operational set of switches; Including, The converter comprises: The one primary coil, and a secondary coil connected to the load through an output switch set; Including, The one primary coil is connected to the N battery sources through N switch sets, and an n-th switch set among the N switch sets is connected to an n-th battery source among the N battery sources, where N is an integer equal to or greater than 2, and n is from 1 to N; The load includes a power conversion system. Converter control method.

6. a step of activating a switch set corresponding to the one battery source to transmit an output of the one battery source to the one primary coil, and deactivating switch sets corresponding to the remaining battery sources other than the one battery source among the N battery sources to cut off the outputs of the remaining battery sources from the one primary coil, 6. The converter control method according to claim 5, further comprising the step of controlling the N switch sets so that only an output of a switch set corresponding to the one battery source is transmitted to a primary coil of the converter.

7. The step of controlling the converter to perform DC-DC conversion includes:

7. The converter control method according to claim 5, further comprising the step of controlling the converter to perform DC-DC conversion using one switch set in operation among the N switch sets and an output switch set connected to a load during one time interval.

8. The step of controlling the converter to perform DC-DC conversion includes:

8. The converter control method of claim 7, further comprising the step of controlling the converter in a charging mode to convert power output from a power conversion system included in the load to a voltage level required by the N battery sources using one of the N switch sets that is activated and in operation, and to operate as a bidirectional converter.

9. The step of controlling the converter to perform DC-DC conversion includes:

8. The method of claim 7, further comprising controlling the converter in a discharge mode to convert an output from one of the N battery sources connected to an active switch set to a DC link voltage that is at a voltage level required by a power conversion system included in the load.

10. N battery sources; A DC-DC converter including a single primary coil, a secondary coil connected to a load, and N switch sets; and a controller for controlling the DC-DC converter such that only one switch set of the N switch sets is activated in one time period, thereby causing the single primary coil to transfer power from one of the N battery sources to a load and cut off power from the remaining battery sources of the N battery sources other than the one battery source from the load. Including, The single primary coil is connected to the N battery sources through the N switch sets, and an n-th switch set among the N switch sets is connected to an n-th battery source among the N battery sources, where N is an integer equal to or greater than 2, and n is from 1 to N; The load includes a power conversion system. Power storage device.

Images