A charging circuit of a power cabinet, a power cabinet and a storage and charging system

Abstract

The application provides a charging circuit of a power cabinet, the power cabinet and a storage and charging system; wherein the energy storage converter is connected with the energy storage equipment through the power cabinet and a charging pile cluster; the charging circuit comprises parallel branch circuits, a DC-DC conversion module is connected in series on each branch circuit, and the DC-DC conversion module is connected with a corresponding charging pile in the charging pile cluster through a power distribution unit. The application has the advantages of simple structure, low construction cost, combined application of the parallel branch circuit and the DC-DC conversion module connected in series on each branch circuit, realization of DC side circuit coupling, flexible switching of the DC-DC conversion module and the corresponding circuit by using the power distribution unit, and thus efficient, stable and safe charging process is ensured.

Description

Technical Field

[0001] This application relates to the field of charging technology, specifically to a charging circuit, power cabinet, and energy storage system for a power cabinet. Background Technology

[0002] The growing demand for fast charging for new energy vehicles has brought unprecedented challenges to the power system. Among these challenges, the power supply system of charging stations, as the core of energy transfer and allocation during the charging process, directly determines the charging speed, stability, and safety. On the one hand, high-power fast charging requires the power supply system to have a strong instantaneous discharge capacity to meet the vehicle's demand for a large amount of electrical energy in a short period of time; on the other hand, frequent high-power charging and discharging pose stringent challenges to the lifespan, heat dissipation, and electrical stability of energy storage systems.

[0003] Currently, the energy storage and charging structure of conventional charging stations has many drawbacks, such as: 1. During the charging process, due to the lack of hardware support structure in the charging circuit, when a new vehicle to be charged is added, it will cause the charging time of the original vehicle to be charged to be unstable.

[0004] 2. Regarding the utilization of AC / DC conversion modules in the power cabinet: AC / DC conversion modules are responsible for converting electrical energy between different voltage levels to meet the charging needs of vehicle batteries. However, in existing systems, when vehicles are connected in large numbers, module overload can easily lead to overheating and module failure. If multiple modules fail simultaneously or sequentially, it may cause the charging station to freeze or go into standby mode, paralyzing the entire charging facility.

[0005] In summary, with the continuous growth of new energy vehicle ownership and the significant increase in fast charging demand, the existing energy storage and charging circuit structure has problems such as unreasonable line connection methods and module utilization when dealing with fluctuations in power demand. There is a need for a charging circuit that supports flexible switching of circuits and charging modules to ensure that the charging process is efficient, stable and safe. Utility Model Content

[0006] This application addresses the problems existing in the prior art by providing a charging circuit with a simple structure that supports switching of connection structures and charging modules, so as to realize the adaptation of automatic circuit path switching and support diversified design of module calling, so as to achieve efficient, stable and safe charging process.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows: On one hand, this application provides a charging circuit for a power cabinet, which is connected to a charging pile cluster, the charging pile cluster including one or more charging piles; the charging circuit includes: Parallel branch circuits, each branch circuit is connected in series with a DC-DC conversion module; the power cabinet is equipped with at least two sets of parallel branch circuits, each set of parallel branch circuits is connected to an input terminal; The DC-DC conversion module is connected to the power distribution unit through multiple branches; the power distribution unit is connected to the corresponding charging pile in the charging pile cluster. In this charging pile cluster, each charging pile can be connected to some or all of the DC-DC conversion modules of the power cabinet through at least one power distribution unit.

[0008] Optionally, each set of parallel branch circuits is provided with multiple primary branches and connected in series with a DC-DC conversion module; the primary branch is an open circuit structure, and the positive and negative wires of the primary branch are connected to the positive and negative terminals of the parallel branch circuit, respectively. The downstream of the DC-DC conversion module has multiple secondary branches, and each of the multiple secondary branches is connected to a power distribution unit. The secondary branches are loop structures, with the positive and negative wires of the primary branch connected at both ends.

[0009] Optionally, each power distribution unit corresponds to at least one set of parallel branch circuits, and the input side of the power distribution unit is connected to the secondary branch of the parallel branch circuit, while the output side of the power distribution unit is connected to the DC charging interface of the charging pile.

[0010] Optionally, each charging station in the charging station cluster is connected to at least two power distribution units; When the number of power distribution units connected to the same charging pile is 2, a daisy-chain interconnection structure is constructed on the output side of the power distribution units of the same charging pile. When the number of power distribution units connected to the same charging pile is greater than 2, a polygonal topology connection and / or a star connection interconnection structure is constructed on the output side of the power distribution unit of the same charging pile.

[0011] Optionally, an isolating switch and a first DC protection circuit are sequentially provided at the DC input terminal of the DC power cabinet; The midpoint of the first DC protection circuit is grounded, and its two ends are connected to the DC positive bus and the DC negative bus, respectively. The lines on both sides of the midpoint of the first DC protection circuit are connected in series with a first fuse and a first DC surge protector. A second fuse is connected in series on the DC positive bus downstream of the first DC protection circuit.

[0012] Optionally, a first pre-charge circuit is provided at the DC input terminal of the DC power cabinet; On the DC positive bus and DC negative bus of the DC power cabinet, a first contactor is provided respectively, and the first pre-charge circuit is connected across the two ends of the first contactor on the DC positive bus. A second contactor and a first resistor are connected in series in the first pre-charge circuit.

[0013] Optionally, a second DC protection circuit is provided on the output circuit of the charging pile; The midpoint of the second DC protection circuit is grounded, and its two ends are connected to the positive output line and the negative output line, respectively. The lines on both sides of the midpoint of the second DC protection circuit are connected in series with a third fuse and a second DC surge protector. A fourth fuse is connected in series on the positive output line downstream of the second DC protection circuit.

[0014] Optionally, a second pre-charge circuit is provided on the output circuit of the charging pile; A second contactor is provided on the positive and negative output lines of the charging pile, and the second pre-charge circuit is connected across the two ends of the second contactor on the positive output line. A third contactor and a second resistor are connected in series in the second pre-charge circuit.

[0015] On the other hand, this application provides a power cabinet that includes the charging circuit of the power cabinet as described above.

[0016] Furthermore, this application provides a power storage and charging system, which includes the power cabinet as described above, and further includes: Energy storage converters, energy storage devices and charging pile clusters; The input circuit is connected to the energy storage device through an energy storage converter; both the energy storage converter and the energy storage device are connected to the power cabinet.

[0017] Compared with the prior art, this application has the following advantages: This application features a simple structure and low construction cost. By combining parallel branch circuits and DC-DC conversion modules connected in series on each branch circuit, DC-side circuit coupling is achieved. Furthermore, the power distribution unit enables flexible switching between the DC-DC conversion modules and corresponding circuits, thereby ensuring efficient, stable, and safe charging. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a simplified diagram of the charging circuit structure in a specific embodiment of this application; Figure 2 This is a simplified circuit diagram of the internal circuit of the DC power cabinet in a specific embodiment of this application; Figure 3 This is a simplified diagram of the parallel branch circuit in a specific embodiment of this application; Figure 4 This is a schematic diagram of the internal circuit of the power distribution unit in a specific embodiment of this application; Figure 5 This is a simplified diagram of the charging pile cluster and the internal structure of the charging piles in a specific embodiment of this application; Figure 6 This is a simplified circuit diagram of the charging pile in a specific embodiment of this application; Figure 7 This is a simplified circuit diagram of the DC power cabinet and charging pile in a specific embodiment of this application.

[0020] In the diagram: 1. Input circuit, 2. Energy storage converter, 3. Energy storage device, 4. DC power cabinet, 5. Charging pile cluster, 41. Parallel branch circuit, 51. Charging pile, 411. First pre-charge circuit, 412. DC-DC conversion module, 413. Power distribution unit, 414. First DC protection circuit, 415. Second fuse, 416. Primary branch, 417. Secondary branch, 511. Interconnection structure, 512. Second pre-charge circuit, 513. Charging interface, 514. Second DC protection circuit, 4131. Input terminal of power distribution unit, 4132. Output terminal of power distribution unit. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this application, it should be understood that the relative relationship indicated by terms such as "upstream" and "downstream" is based on the direction of current in actual application and is used for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific location, and therefore should not be construed as a limitation of this application.

[0024] In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically defined.

[0025] In this application, unless otherwise expressly specified and limited, the terms "provided with" and "connected in series" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] like Figure 1 As shown in the figure, this application provides a power storage and charging system, which includes the power cabinet as described in the following embodiments, and further includes: an energy storage converter 2, an energy storage device 3, and a charging pile cluster 5. The input circuit 1 is connected to the energy storage device 3 via the energy storage converter 2; both the energy storage converter 2 and the energy storage device 3 are connected to the power cabinet.

[0027] Among them, the Power Conversion System (PCS) is a device used in the fields of new energy, energy storage, and power electronics to realize the conversion, regulation, and management of electrical energy forms. Its main function is to build transmission and conversion channels between different electrical energy carriers, such as energy storage batteries, power grids, and loads, to meet the power supply and demand matching requirements in different scenarios. Existing PCS mainly consists of power electronic switching devices, such as IGBTs, SiC MOSFETs, control units, filter circuits, and protection circuits, and is widely used in scenarios such as energy storage power stations, new energy vehicle charging facilities, distributed photovoltaic / wind power grid connection, and microgrids. In this embodiment, the Power Conversion System 2 is connected to an external power source, including but not limited to the power grid and new energy power stations, through the input circuit 1; its function is to perform bidirectional conversion between direct current (DC) and alternating current (AC), converting the received AC power into DC power and supplying power to the next level.

[0028] The output side of the energy storage converter 2 is connected to the energy storage device 3 via a cable. In this embodiment, the energy storage device 3 may include a DC energy storage device, an AC energy storage device, an integrated AC / DC energy storage device, or a separate AC / DC energy storage device; existing DC energy storage devices include energy storage battery packs, battery management systems (BMS), DC-side interface units, thermal management systems, and safety protection systems. It is used to store electrical energy and supply power to the next level or the external grid when needed.

[0029] By combining the upstream energy storage converter 2 and energy storage device 3, the application of protection devices in subsequent circuits, such as surge protectors and circuit breakers, can be reduced, thereby reducing the overall cost.

[0030] In this embodiment, the power cabinet may include a DC power cabinet 4, an AC power cabinet, an integrated AC / DC power cabinet, and a separate AC / DC power cabinet. Because charging station configurations vary, multiple power cabinets can be configured according to actual needs. However, for simplicity, this embodiment describes a single DC power cabinet 4, which should not be interpreted as a limitation. Both the energy storage converter 2 and the energy storage device 3 are connected to the DC power cabinet 4.

[0031] In this embodiment, the charging pile cluster 5 should be understood as a cluster of charging piles 51 within the same electrical area of ​​a charging station, wherein one or more charging piles 51 are distributed and connected to the same DC power cabinet 4. In other embodiments, the connection method may also be that multiple charging piles 51 are respectively connected to multiple DC power cabinets 4, or one charging pile 51 is connected to multiple DC power cabinets 4.

[0032] like Figure 2 As shown, this embodiment provides a charging circuit for a power cabinet, which is applied (installed) in the DC power cabinet 4 of the aforementioned embodiment. The charging circuit of the DC power cabinet 4 in this embodiment includes at least two sets of parallel branch circuits 41, and each set of branch circuits is independent of each other. Each set of branch circuits is connected to a DC input terminal of a DC power cabinet 4. Thus, each DC power cabinet 4 can couple multiple DC inputs as needed to achieve convenient expansion functionality.

[0033] Furthermore, a first pre-charge circuit 411 is set on the circuit corresponding to each DC input terminal, and a DC-DC converter (DC / DC) module is connected in series on each branch. Specifically, the circuit corresponding to each DC input terminal is connected to multiple DC-DC converter modules 412 through a primary branch 416. Multiple power distribution units (PDUs) are also set in the DC power cabinet 4 for line switching. Thus, in order to achieve a full connection design between the power consumption side and the DC-DC converter module 412, multiple secondary branches 417 are set downstream of the DC-DC converter module 412 on each branch, and the secondary branches 417 are respectively connected to the corresponding power distribution units 413, and the power distribution units 413 are connected to the corresponding charging piles 51 in the charging pile cluster 5.

[0034] Furthermore, combining Figure 3 , Figure 4 and Figure 7As shown, this embodiment uses a DC power cabinet 4 with two sets of parallel branch circuits 41 as an example for explanation. A disconnect switch and a first DC protection circuit 414 are sequentially installed at the DC input terminal of the DC power cabinet 4. The midpoint (one end) of the first DC protection circuit 414 is grounded, and the other two ends are connected to the DC positive bus (+) and the DC negative bus (-), respectively. A first fuse and a first DC surge protector are connected in series on both sides of the midpoint of the first DC protection circuit 414. Specifically, the structure of the first DC protection circuit 414 is as follows: the DC positive and negative buses are connected in series with the first fuse and the first DC surge protector through connection points, and the first DC surge protectors on both sides are connected to the midpoint of the protection circuit. The midpoint is reliably grounded through a grounding electrode, forming a symmetrical clamp-type protection circuit. A second fuse 415 is also connected in series on the DC positive bus (+) downstream of the first DC protection circuit 414. In this embodiment, first contactors are respectively installed on the DC positive bus (+) and DC negative bus (-) downstream of the second fuse 415, and the two ends of the first contactor on the DC positive bus (+) are connected across a first pre-charge circuit 411. A second contactor and a first resistor are connected in series on the first pre-charge circuit 411. The first pre-charge circuit 411 is used to prevent excessive instantaneous charging current of capacitive devices in the circuit when the circuit starts. The principle is that when the circuit starts working, the first pre-charge circuit 411 is first connected to allow the capacitive devices to charge slowly (i.e., pre-charge). After a certain safe voltage is reached, the first contactor of the DC positive bus (+) (also called the DC bus main contactor) closes, and the circuit operates normally. This can extend the equipment life, improve stability, reduce the impact of shocks on the system, and thus protect circuit components.

[0035] In this embodiment, each group of parallel branch circuits 41 has a total of 6 primary branches 416, each connected in series with a DC-DC conversion module 412. Each primary branch 416 also has 4 secondary branches 417, which are connected to the corresponding power distribution unit input terminal 4131. In the power distribution unit 413, the input circuits are connected to the power distribution unit output terminal 4132 after passing through a relay, and are connected to the charging interface 513 of the charging pile 51. The primary branch 416 adopts an open circuit structure, with one end of its positive and negative lines connected to the positive and negative terminals of the parallel branch circuit 41, respectively, and the other end in an open circuit state. Correspondingly, the two ends of the positive side of the DC-DC conversion module 412 are connected in series to the positive line of the primary branch 416, and the two ends of the negative side of the DC-DC conversion module 412 are connected in series to the negative line of the primary branch 416. The secondary branch 417 adopts a loop structure, with its positive and negative lines connected to the corresponding positive and negative lines of the primary branch 416, respectively. The end of the secondary branch 417 is connected to the corresponding charging load (new energy vehicle) through the power distribution unit 413.

[0036] To achieve the aforementioned fully connected design, each charging pile 51 in the charging pile cluster 5 is connected to all DC-DC conversion modules 412 of the DC power cabinet 4 through at least one power distribution unit 413. In this embodiment, a total of 8 power distribution units 413 are designed, divided into 4 groups corresponding to 4 charging piles 51; the input terminal 4131 of each group of power distribution units is connected to all 12 DC-DC conversion modules 412 in the two groups of parallel branch circuits 41, and the output terminal 4132 of the power distribution unit is connected to one charging pile 51 in the charging pile cluster 5.

[0037] like Figure 5 and Figure 6 As shown, the charging pile 51 in this embodiment is provided with an interconnection structure 511 and an output circuit that connects to the charging interface 513.

[0038] This embodiment uses a dual-specification interface as an example. The charging interface 513 includes Combined Charging System Type 1 (CCS1) and North American Charging Standard (NACS). The interconnection structure 511 is used to further realize the hardware design of fully connected and switchable control, enabling the power distribution unit output terminal 4132 to interconnect with either of the above two types of interfaces. Therefore, in this embodiment, since the number of power distribution units 413 in the same charging pile 51 is 2, a daisy-chain interconnection structure 511 is constructed on the output side of the power distribution units 413 in the same charging pile 51, such as... Figure 6 As shown. This ensures that any type of interface can connect to any power distribution unit 413 within the group, thereby achieving a fully connected design that connects to any DC-DC conversion module 412.

[0039] Through the above design, this embodiment can achieve the connection between any charging interface 513 and any DC-DC conversion module 412 in the cluster by switching control, thereby adjusting the number of DC-DC conversion modules 412 in use and the module utilization rate in real time; especially when one DC-DC conversion module 412 fails, the remaining idle DC-DC conversion modules 412 can be seamlessly switched in to replace the failed module; it can also realize that multiple DC-DC conversion modules 412 can be connected to the same charging interface 513 by coordination, thereby improving the maximum charging power of a single gun.

[0040] In other embodiments, when the number of power distribution units 413 connected to the same charging pile 51 is greater than 2, a polygonal topology interconnection structure can be constructed on the output side of the power distribution units 413 of the same charging pile 51. For example, a three-branch scenario corresponds to a triangle connection, a four-branch scenario corresponds to a quadrilateral connection, or a five-branch scenario corresponds to a pentagonal connection, and so on. Similarly, a star-shaped interconnection structure can also be selected, that is, each type of charging interface 513 is connected to the common point of the star-shaped interconnection structure, and the star branches of the star-shaped interconnection structure are connected in series with adjacent relays and then connected to the corresponding power distribution unit output terminal 4132.

[0041] Furthermore, in the charging pile 51, a second DC protection circuit 514 is provided on the output circuit after the interconnection structure 511. The midpoint of the second DC protection circuit 514 is grounded, and its two ends are connected to the output positive line and the output negative line, respectively. Similar to the structure of the aforementioned first DC protection circuit 414, a third fuse and a second DC surge protector are connected in series on the lines on both sides of the midpoint of the second DC protection circuit 514. Furthermore, a fourth fuse is also connected in series on the output positive line downstream of the second DC protection circuit 514.

[0042] Furthermore, a second pre-charge circuit 512 is provided downstream of the fourth fuse. Specifically, second contactors are respectively provided on the positive and negative output lines near the charging interface 513 of the charging pile 51; the second pre-charge circuit 512 is connected across the two ends of the second contactor on the positive output line. A third contactor and a second resistor are connected in series on the second pre-charge circuit 512, and their principle and function are similar to those of the first pre-charge circuit 411, used to protect the electrical system of the charging vehicle and improve charging stability.

[0043] On the other hand, this embodiment also provides a power cabinet in which the above-mentioned charging circuit is applied.

[0044] Finally, it should be noted that the above content is only used to illustrate the technical solution of this application, and is not intended to limit the scope of protection of this application. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of this application shall not depart from the substance and scope of the technical solution of this application.

Claims

1. A charging circuit for a power cabinet, characterized in that, The power cabinet is connected to a charging pile cluster, which includes one or more charging piles; the charging circuit includes: The power cabinet is equipped with at least two sets of parallel branch circuits, each set of which is connected in series with a DC-DC conversion module. The DC-DC conversion module is connected to the power distribution unit through multiple branches; the power distribution unit is connected to the corresponding charging pile in the charging pile cluster. In this configuration, each charging pile in the charging pile cluster can be connected to some or all of the DC-DC conversion modules of the power cabinet through at least one power distribution unit.

2. The charging circuit of the power cabinet according to claim 1, characterized in that, Each set of parallel branch circuits has multiple primary branches; the primary branch is an open circuit structure, and the positive and negative wires of the primary branch are respectively connected to the positive and negative terminals of the parallel branch circuit. The DC-DC conversion module has multiple secondary branches downstream, and each of the secondary branches is connected to a power distribution unit. The secondary branches are loop structures, with their two ends connected to the positive and negative wires of the primary branch, respectively.

3. The charging circuit of the power cabinet according to claim 2, characterized in that, Each power distribution unit corresponds to at least one set of parallel branch circuits, and the input side of the power distribution unit is connected to the secondary branch of the parallel branch circuit, while the output side of the power distribution unit is connected to the DC charging interface of the charging pile.

4. The charging circuit of the power cabinet according to claim 1, characterized in that, Each charging pile in the charging pile cluster is connected to at least two power distribution units; When the number of power distribution units connected to the same charging pile is 2, a daisy-chain interconnection structure is constructed on the output side of the power distribution units of the same charging pile. When the number of power distribution units connected to the same charging pile is greater than 2, a polygonal topology connection and / or a star connection interconnection structure is constructed on the output side of the power distribution unit of the same charging pile.

5. The charging circuit of the power cabinet according to claim 1, characterized in that, An isolating switch and a first DC protection circuit are sequentially provided at the DC input terminal of the power cabinet; The midpoint of the first DC protection circuit is grounded, and its two ends are connected to the DC positive bus and the DC negative bus, respectively. The lines on both sides of the midpoint of the first DC protection circuit are connected in series with a first fuse and a first DC surge protector. A second fuse is connected in series on the DC positive bus downstream of the first DC protection circuit.

6. The charging circuit of the power cabinet according to claim 1, characterized in that, A first pre-charge circuit is provided at the DC input terminal of the power cabinet; On the DC positive bus and DC negative bus of the power cabinet, a first contactor is provided respectively, and the first pre-charge circuit is connected across the two ends of the first contactor on the DC positive bus. A second contactor and a first resistor are connected in series in the first pre-charge circuit.

7. The charging circuit of the power cabinet according to claim 1, characterized in that, A second DC protection circuit is provided on the output circuit of the charging pile; The midpoint of the second DC protection circuit is grounded, and its two ends are connected to the positive output line and the negative output line, respectively. The lines on both sides of the midpoint of the second DC protection circuit are connected in series with a third fuse and a second DC surge protector. A fourth fuse is connected in series on the positive output line downstream of the second DC protection circuit.

8. The charging circuit of the power cabinet according to claim 1, characterized in that, A second pre-charge circuit is provided on the output circuit of the charging pile; A second contactor is provided on the positive and negative output lines of the charging pile, and the second pre-charge circuit is connected across the two ends of the second contactor on the positive output line. A third contactor and a second resistor are connected in series in the second pre-charge circuit.

9. A power cabinet, characterized in that, The charging circuit includes the power cabinet as described in any one of claims 1 to 8.

10. A storage and charging system, characterized in that, Including the power cabinet as described in claim 9, it further includes: Energy storage converters, energy storage devices and charging pile clusters; The input circuit is connected to the energy storage device through the energy storage converter; both the energy storage converter and the energy storage device are connected to the power cabinet.

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