A high-voltage box of a medium-high voltage direct-hanging energy storage system

Abstract

This invention provides a high-voltage box for a medium- and high-voltage direct-connected energy storage system. The input terminals of the redundant power supply receive AC and DC power through corresponding conversion units. The AC power supply conversion unit employs an isolation current transformer (CT). A DC switch is located between the battery and the power supply unit (PCS) in the energy storage system. A power supply control unit (BCMU) controls the switching on and off of the DC switch. The output terminals of the redundant power supply power the BCMU and other electrical components. This high-voltage box can be applied to medium- and high-voltage direct-connected energy storage systems, primarily considering power isolation. Furthermore, the high-voltage box features a redundant and reliable power supply design, employing a dual-power supply method: one channel uses a high-voltage isolation CT to receive AC power, and the other channel uses a DC battery bus power supply. This ensures that in extreme cases, even if the entire power system loses power, the DC bus power supply method guarantees a black start for the medium- and high-voltage direct-connected energy storage system, driving important loads and gradually restoring the power system to normal operation.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, and more specifically, relates to a high-voltage box for a medium- and high-voltage direct-connected energy storage system. Background Technology

[0002] Medium- and high-voltage direct-connected energy storage systems have advantages such as large single-unit capacity, high system efficiency, and space saving, and have attracted widespread attention in applications such as new energy power generation, power supply side, and grid side. The high-voltage box is an important component of the BMS (Battery Management System), which internally includes the BCMU (Battery Cluster Management Unit), shunts or Hall current detectors, circuit breakers, contactors, soft-start circuits, and various connection terminals.

[0003] The high-voltage box communicates with the PCS (Power Control System, energy storage converter) and BAMS (Battery Array Management System) via CAN (Controller Area Network) to manage the batteries, collect the voltage and temperature of each cell, collect the voltage and current of the battery pack, and participate in the calculation of SOC (State of Charge), SOH (State of Health), and DC-side power. Simultaneously, the PCS maintains CAN or 485 communication with the BCMU inside the high-voltage box, resolving important information for PCS control, such as the SOC of each battery cluster, to participate in intra-phase and inter-phase SOC balancing control. The BMS uploads PCS alarm signals and PCS protection signals to the PCS or connects them in series to the high-voltage circuit breaker trip coil. When a battery issues a level 3 alarm (such as a level 3 temperature overshoot), the PCS protection signal dry contact closes, quickly disconnecting the energy storage system's incoming circuit breaker, disconnecting the energy storage system from the grid, locating the fault, activating relevant protections, and ensuring the safety of the energy storage system.

[0004] Medium- and high-voltage direct-connected energy storage systems typically operate in 3kV to 35kV power systems. Each converter unit is connected one-to-one with each battery cluster. The operating voltage of the converter unit and battery system relative to ground is 3kV to 35kV, and the high-voltage box is also the same. Traditional low-voltage energy storage solutions' high-voltage boxes cannot be used in medium- and high-voltage direct-connected energy storage systems, mainly due to power isolation considerations. Furthermore, the functionality of low-voltage energy storage high-voltage boxes cannot meet the requirements of high-voltage boxes in medium- and high-voltage direct-connected energy storage systems. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a high-voltage box for a medium- and high-voltage direct-connected energy storage system, which is used for the medium- and high-voltage direct-connected energy storage system and ensures the black start of the medium- and high-voltage direct-connected energy storage system, drives the important loads of the power system, and gradually restores the normal operation of the power system.

[0006] This application discloses a high-voltage box for a medium-high voltage direct-connected energy storage system, including: a DC switch, a battery management control unit (BCMU), and a redundant power supply;

[0007] The input terminals of the redundant power supply receive AC power and DC power through corresponding conversion units; wherein, the conversion unit corresponding to the AC power supply adopts an isolated CT.

[0008] The DC switch is located between the battery and the PCS in the energy storage system;

[0009] The BCMU is used to control the on / off state of the DC switch;

[0010] The output of the redundant power supply powers the BCMU and other electrical devices.

[0011] Optionally, in the high-voltage box of the above-mentioned medium- and high-voltage direct-connected energy storage system, the input terminal of the redundant power supply is connected to the AC power supply through the AC / DC conversion unit of the high-voltage isolation CT.

[0012] The input terminal of the redundant power supply is also connected to a high-voltage DC power supply through a high-voltage isolated DC / DC converter unit.

[0013] The output terminals of the redundant power supply are respectively the BCMU, the core board of the converter unit of the energy storage system, and the battery management system (BMS).

[0014] Optionally, the high-voltage box of the aforementioned medium- and high-voltage direct-connected energy storage system also includes: a current detection module;

[0015] The current detection module is used to detect the battery current value of the energy storage system and transmit the battery current value to the BCMU.

[0016] Optionally, in the high-voltage box of the above-mentioned medium- and high-voltage direct-connected energy storage system, the BCMU is also used to receive the status feedback from the DC switch; and to determine the status parameters of the battery based on the battery current value, and to control the PCS in the energy storage system based on the status parameters.

[0017] Optionally, in the high-voltage box of the above-mentioned medium- and high-voltage direct-connected energy storage system, the communication method between the BCMU and the energy storage system is 485 and CAN communication.

[0018] Optionally, the high-voltage box of the aforementioned medium- and high-voltage direct-connected energy storage system also includes: a CAN-to-optical module;

[0019] The CAN-to-optical module is used to convert CAN signals into optical signals.

[0020] Optionally, in the high-voltage box of the aforementioned medium- and high-voltage direct-connected energy storage system, the CAN-to-optical module is powered by the redundant power supply.

[0021] Optionally, in the high-voltage box of the above-mentioned medium- and high-voltage direct-connected energy storage system, the BCMU communicates with the CAN-to-optical module;

[0022] The CAN-to-optical module communicates with the optical-to-CAN module in the energy storage system;

[0023] The optical-to-CAN module communicates with the Battery Management System (BAMS) in the energy storage system.

[0024] The BAMS communicates with the energy management system (EMS) in the energy storage system.

[0025] Optionally, in the high-voltage box of the above-mentioned medium- and high-voltage direct-connected energy storage system, the CAN-to-optical module is powered by a first power supply, and the optical-to-CAN module and the BAMS are powered by a second power supply.

[0026] Optionally, the high-voltage box of the above-mentioned medium- and high-voltage direct-connected energy storage system also includes: inlet and outlet terminal blocks;

[0027] The redundant power supply communicates with the outside world through the incoming and outgoing terminal blocks.

[0028] As can be seen from the above technical solution, the high-voltage box of the medium-high voltage direct-connected energy storage system provided by the present invention includes: a DC switch, a battery management main control unit (BCMU), and a redundant power supply; the input end of the redundant power supply receives AC power and DC power through corresponding conversion units; wherein, the conversion unit corresponding to the AC power supply adopts an isolation CT; the DC switch is set between the battery and the PCS in the energy storage system; the BCMU is used to control the opening and closing of the DC switch; the output end of the redundant power supply supplies power to the BCMU and other electrical components. This high-voltage box can be applied to medium-high voltage direct-connected energy storage systems, and its design mainly considers power isolation; at the same time, the power supply of the high-voltage box is designed for redundant reliability, adopting a dual power supply mode, one of which uses a high-voltage isolation CT to receive AC power, and the other uses a DC battery bus power supply, ensuring that in extreme cases, if the entire power system loses power, the DC power bus power supply mode can ensure the black start of the medium-high voltage direct-connected energy storage system, drive the important loads of the power system, and gradually restore the normal operation of the power system. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the high-voltage box of a medium-high voltage direct-connected energy storage system provided in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of a redundant power supply in the high-voltage box of a medium-high voltage direct-connected energy storage system provided in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the communication process in the high-voltage box of a medium-high voltage direct-connected energy storage system provided in an embodiment of the present invention;

[0033] Figure 4 This is the appearance design of a medium-high voltage direct-connected energy storage system provided in an embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0036] This application provides a high-voltage box for a medium- and high-voltage direct-connected energy storage system, which solves the problem that the high-voltage boxes of traditional low-voltage energy storage schemes in the prior art cannot be applied to medium- and high-voltage direct-connected energy storage systems, mainly due to considerations of power isolation. At the same time, the functions of the high-voltage boxes for low-voltage energy storage cannot meet the requirements of the high-voltage boxes for medium- and high-voltage direct-connected energy storage systems.

[0037] like Figure 1As shown, the high-voltage box of this medium-high voltage direct-connected energy storage system includes: a DC switch (such as...) Figure 1 The DC circuit breaker / DC contactor shown), and the battery management control unit (BCMU) (as shown) Figure 1 The diagram shows a binary master control unit (BCMU) and a redundant power supply.

[0038] The input terminals of the redundant power supplies are respectively connected to corresponding conversion units (such as...). Figure 1 The power conversion shown receives both AC and DC power; the conversion unit corresponding to the AC power supply uses an isolated CT.

[0039] Specifically, the input of the redundant power supply receives AC power through the first conversion unit, such as when connected to the power grid, and receives DC power through the second conversion unit, such as the DC bus of the battery in the energy storage power supply.

[0040] The specific connection relationships of the input terminals of this redundant power supply will not be detailed here. As long as it has both AC and DC power supplies, and the AC power supply uses an isolated current transformer (CT), it is all within the protection scope of this application. It should be noted that PT stands for voltage transformer, and CT stands for current transformer.

[0041] The redundant power supply adopts a dual power source approach, with one source drawing power from an external AC isolation CT and the other from a DC bus. A power redundancy control board is designed to improve the reliability of the power supply.

[0042] A DC switch is installed between the battery and the PCS in the energy storage system. P+ is the positive terminal of the PCS, and P- is the negative terminal of the PCS; B+ is the positive terminal of the battery, and B- is the negative terminal of the battery.

[0043] The BCMU is used to control the switching on and off of the DC switch. In other words, the energy storage system can be protected by controlling the switching on and off of this DC switch. The specific working process will not be described in detail here, but will depend on the actual situation, and all are within the scope of protection of this application.

[0044] In practical applications, DC switches are either DC circuit breakers or DC contactors.

[0045] In other words, the DC switch can be a DC circuit breaker or a DC contactor; of course, a combination of a DC circuit breaker and a DC contactor is also possible. These will not be elaborated on here, but will be determined according to the actual situation, and all are within the protection scope of this application.

[0046] Specifically, one path of the redundant power supply uses a high-voltage isolated CT to draw power, and outputs 24V through AC / DC conversion; the other path of the redundant power supply uses a high-voltage DC bus to draw power, and outputs 24V through DC / DC conversion; the two 24V DC outputs are smoothly switched through the power redundancy control board, i.e., the redundant power supply, to achieve reliable power supply to the load.

[0047] The output of the redundant power supply powers the BCMU and other electrical devices.

[0048] In other words, in extreme cases where the entire power system loses power, a DC power supply can be used to ensure the black start of the medium- and high-voltage direct-connected energy storage system, thereby driving important loads of the power system and gradually restoring the normal operation of the power system.

[0049] It should be noted that the above description is based on the medium- and high-voltage direct-connected energy storage system with a ground floating voltage of 3kV to 35kV, that is, the high-voltage box can be applied to medium- and high-voltage direct-connected energy storage systems.

[0050] In this embodiment, the high-voltage box can be applied to medium- and high-voltage direct-connected energy storage systems, mainly considering power isolation. Simultaneously, the high-voltage box features a redundant and reliable power supply design, employing a dual-power supply method: one supply uses a high-voltage isolation CT to receive AC power, and the other uses a DC battery bus power supply. This ensures that in extreme cases, if the entire power system loses power (complete blackout), the DC power bus supply method can guarantee a black start for the medium- and high-voltage direct-connected energy storage system, driving important loads of the power system and gradually restoring normal operation of the power system.

[0051] It should be noted that existing technologies using traditional isolation power extraction methods employ voltage-isolated power supply (PTs). For lower voltage levels, such as 3kV to 10kV, the isolation PT solution can still meet design requirements in terms of size and weight. However, when the voltage level is 20kV to 35kV, the isolation PT's insulation frame is relatively large and heavy, which will significantly impact the improvement of the battery volume ratio of the containerized energy storage system. The presence of the isolation PT reduces the battery volume ratio of the containerized energy storage system and brings great difficulty to the structural design.

[0052] In this embodiment, the dual power supply adopts a redundant and smooth design scheme to ensure that the high-voltage isolated CT power supply is used under normal system operation, thereby improving battery capacity utilization and efficiency.

[0053] In practical applications, such as Figure 2 As shown, the input terminal of the redundant power supply is connected to the AC power supply through the AC / DC conversion unit of the high-voltage isolation CT.

[0054] Specifically, the AC side of the AC / DC converter unit of the high-voltage isolation CT is connected to the AC power supply; the DC side of the AC / DC converter unit of the high-voltage isolation CT is connected to the input terminal of the redundant power supply.

[0055] The input of the redundant power supply is also connected to a high-voltage DC power supply through a high-voltage isolated DC / DC converter unit.

[0056] Specifically, one side of the high-voltage isolated DC / DC converter unit is connected to a high-voltage DC power supply, such as the DC bus of a battery in an energy storage system; the other side of the high-voltage isolated DC / DC converter unit is connected to the input of a redundant power supply.

[0057] It should be noted that the power of the high-voltage isolated DC / DC converter unit and the AC / DC converter unit of the high-voltage isolated CT are combined before being transmitted to the redundant power supply; of course, a scheme that does not combine the power can also be adopted, which will not be elaborated here, depending on the actual situation, and all are within the protection scope of this application.

[0058] The input voltage at the input terminal of the redundant power supply can be 24V, or other values, which will not be elaborated here, and are all within the protection scope of this application.

[0059] The output terminals of the redundant power supplies are the BCMU, the core board of the converter unit of the energy storage system, and the BMS power supply.

[0060] like Figure 2 and Figure 1 As shown, the output of the redundant power supply is 24V for the BCMU; at the same time, it also supplies power to the core board of the converter unit, i.e. the PCS core board, and the BMS.

[0061] It should be noted that the high-voltage box may also include an electrical control (such as...) Figure 3 (The electrified operation shown).

[0062] The electric actuator is used to complete automatic control through auxiliary contacts. Its specific working process will not be described in detail here, but can be determined according to the actual situation, and all are within the protection scope of this application.

[0063] It should be noted that the electrical control can also be powered by this redundant power supply.

[0064] In practical applications, the high-voltage box also includes a current detection module.

[0065] The current detection module is used to detect the battery current value of the energy storage system and transmit the battery current value to the BCMU.

[0066] Specifically, the current detection module includes a Hall current sensor and a current module. The Hall current sensor acquires the battery current value, then transmits the battery current value to the current module, which in turn transmits the battery current value to the BCMU.

[0067] In practical applications, this BCMU is also used to receive the status feedback from the DC switch; and to determine the status parameters of the battery based on the battery current value, and to control the PCS in the energy storage system based on the status parameters.

[0068] As can be seen from the above description, the BCMU can control the state of the DC switch. Therefore, the success of the BCMU control can be determined by obtaining the feedback state of the DC switch. If the control fails, it can be continuous control or even alarm, etc., which will not be elaborated here. It depends on the actual situation and is all within the protection scope of this application.

[0069] Specifically, the Hall current detection element detects the current flowing through each cluster. The BCMU uses this current value to calculate data such as the DC-side power of the battery cluster, the SOC and SOH of each battery cluster, and then uses the data to control the PCS.

[0070] Meanwhile, if the BCMU detects overcharging, over-discharging, or temperature exceeding limits in the battery cell, it will issue a dry contact alarm signal and a protection signal. Normal signals will maintain communication with the PCS via RS-485 and CAN communication. These dry contact alarm and protection signals can also communicate with the PCS via RS-485 and CAN communication to control the PCS's operating status.

[0071] It should be noted that the power redundancy design within the high-voltage box is crucial for reliable power supply. The functional design of the high-voltage box needs to be expanded to suit the characteristics of medium- and high-voltage direct-connected energy storage systems, ensuring the normal operation of the system's protection, communication, and data functions. The structure and panel design of the high-voltage box need to be redesigned to meet the requirements of functional expansion and specific scenario structures for medium- and high-voltage direct-connected energy storage systems.

[0072] In practical applications, the BCMU communicates with the energy storage system using both 485 and CAN communication methods.

[0073] Of course, other communication methods are also possible, which will not be elaborated here. They can be determined according to the actual situation and are all within the scope of protection of this application.

[0074] Furthermore, the specific communication process and content between the BCMU and the energy storage system will not be elaborated here, but will be determined according to the actual situation, and are all within the scope of protection of this application.

[0075] It should be noted that battery management systems (BMS) generally employ a three-tier architecture. The primary slave control unit (BMU) mainly monitors cell voltage and temperature, uploading relevant information to the secondary master control unit (BCMU) via the CAN bus. The BCMU is located in the high-voltage box. Since the secondary master control unit in a medium-to-high voltage direct-connected energy storage system needs to communicate with the tertiary master control unit (BAMS), and the entire system operates in a 3kV–35kV high-voltage environment, direct communication between the secondary master control unit and the tertiary master control unit (BAMS) would burn out the equipment and cause a serious short circuit. To avoid this problem, optical isolation technology is used. Specifically, the BCMU signal transmits cell voltage, temperature, and cluster-related information to the tertiary master control unit (BAMS) via a CAN-to-optical-fiber-to-CAN conversion, where the relevant information is managed and displayed. Both the primary slave control unit (BMU) and the tertiary master control unit (BAMS) are located within the energy storage system.

[0076] Based on this, the high-voltage box may also include: a CAN-to-optical module.

[0077] The CAN-to-optical module is used to convert CAN signals into optical signals.

[0078] The specific conversion process of the CAN-to-optical module will not be described in detail here. For details, please refer to the relevant prior art, all of which are within the protection scope of this application.

[0079] In practical applications, this CAN-to-optical module is powered by a redundant power supply. Of course, it is also possible that the CAN-to-optical module is powered by other power supplies; these will not be elaborated upon here, but will depend on the actual situation, and all are within the scope of protection of this application.

[0080] In practical applications, such as Figure 3 As shown, the BCMU communicates with the CAN-to-optical module.

[0081] In other words, the CAN-to-optical module receives the CAN signal from the BCMU and converts the CAN signal into an optical signal.

[0082] The CAN-to-optical module communicates with the optical-to-CAN module in the energy storage system.

[0083] In other words, the CAN-to-optical module outputs an optical signal to the optical-to-CAN module in the energy storage system. The optical-to-CAN module is used to convert the optical signal into corresponding signals and data.

[0084] The optical-to-CAN module communicates with the Battery Management System (BAMS) in the energy storage system.

[0085] In other words, the optical-to-CAN module transmits the corresponding signals and data to the BAMS; the BAMS then receives and processes the signals and data.

[0086] BAMS communicates with the Energy Management System (EMS) in the energy storage system.

[0087] In other words, the BAMS transmits the processed data and signals to the EMS.

[0088] Specifically, the high-voltage box of the medium- and high-voltage direct-connected energy storage system is equipped with PCS alarm and PCS protection dry contact functions, as well as PCS communication functions such as 485 communication and CAN communication. A high-voltage isolation function for CAN-to-optical signal output is also added. The PCS alarm and PCS protection dry contacts are connected to the output dry contacts of the secondary main control BCMU through isolation. The PCS communication function is connected to the 485 output and CAN output of the secondary main control BCMU through the ARM communication serial communication port and CAN port via isolation. The input signal of the CAN-to-optical module is connected to the CAN communication interface of the secondary main control BCMU, and the CAN-to-optical output signal is connected to the CAN receiving signal via optical fiber.

[0089] In this embodiment, the high-voltage box of the medium- and high-voltage direct-connected energy storage system has been expanded with corresponding functions according to the needs of the application scenario. These functions include medium- and high-voltage cascaded PCS alarm signals, protection signals, communication functions, fire protection functions (isolation), and three-level master control CAN communication functions (CAN to optical isolation). This ensures the safety and reliability of the protection, communication, and fire protection systems of the medium- and high-voltage direct-connected energy storage system. The secondary master control unit (BCMU) inside the high-voltage box and the external tertiary master control unit (BAMS) are completely isolated by using CAN to optical isolation technology and different power supplies and optical isolation to ensure the safe and reliable transmission of signals, while also ensuring the safety of the equipment.

[0090] In practical applications, the CAN-to-optical module uses the first power supply (such as...). Figure 3 The power supply shown is 1), while the optical-to-CAN module and BAMS use a second power supply (such as...). Figure 3 The power supply shown is 2) power supply.

[0091] It should be noted that the first power supply and the second power supply are different because the CAN to optical module, the optical to CAN module, and BAMS use different power supplies.

[0092] The first power supply can be a power supply installed in the high-voltage box; the second power supply can be a power supply installed in the energy storage system; of course, other situations are not excluded, which will not be elaborated here, depending on the actual situation, and all are within the protection scope of this application.

[0093] In practical applications, the high-voltage box may also include: inlet and outlet terminal blocks.

[0094] The redundant power supply is connected to the external environment through the incoming and outgoing terminal blocks.

[0095] The high-voltage box of the medium- and high-voltage direct-connected energy storage system adds a high-voltage isolation power extraction method and DC bus power extraction, as well as terminal input and output. It also adds communication between BMS and PCS, such as 485 and CAN functions and terminal output; it adds dry contact between BMS and PCS, such as PCS alarm and PCS protection functions and terminal output; and it adds high-voltage isolation CAN to optical function for communication between the secondary master control BCMU and the tertiary master control BAMS.

[0096] In this embodiment, the isolation power supply and reliability redundancy design, functional expansion, communication interface design, and overall structure design of the high-voltage box solve the problem that the high-voltage box of the traditional low-voltage energy storage system cannot be directly applied to the medium- and high-voltage direct-connected energy storage system, and ensure the safety and reliability of communication, protection, and control of the medium- and high-voltage direct-connected energy storage system.

[0097] It should be noted that the structure and panel of the high-voltage box are designed specifically for the application scenarios and structural size requirements of medium- and high-voltage direct-connected energy storage systems to meet the functions of signal transmission, protection, and control. The panel of this high-voltage box can be designed as follows: Figure 4 The design shown.

[0098] Interface board 1 may include interfaces for fire protection power supply (±24V) and backup power supply (±24V); interface board 2 may include interfaces for BMS power supply (±24V), BMS communication, and addressing; interface board 3 may include interfaces for CT input power supply; interface board 4 may include interfaces for debugging, PCS-CAN communication, and PCS-485 communication; interface board 5 may include interfaces for PCS power supply (±24V), PCS alarm, and PCS protection; and interface board 6 may include interfaces for CAN to optical interface and fiber optic interface.

[0099] Of course, the settings of each interface are not limited to those described above, and will not be elaborated on here. They can be determined according to the actual situation, and are all within the protection scope of this application.

[0100] Specifically, the high-voltage box panel of the medium- and high-voltage direct-connected energy storage system is designed with added secondary terminals that lead signals out to the front panel via internal leads, facilitating connections with the medium- and high-voltage cascaded PCS for power, signal, dry contacts, and communication. The CAN-to-optical high-voltage isolation system connects to the third-level main control BAMS via fiber optic cables connected to the panel terminals. The panel layout considers ease of wiring while also taking into account the avoidance of various electromagnetic interferences during signal transmission.

[0101] In this embodiment, the high-level power extraction problem has always been one of the main reasons why medium- and high-voltage direct-connected energy storage systems are difficult to promote. This is mainly due to the use of high-voltage power isolation PT technology, which is large in size and weight, making it difficult to implement in medium- and high-voltage direct-connected containerized energy storage systems, reducing the volume ratio of the battery system in containerized energy storage systems, and increasing costs. This invention adopts high-voltage CT isolation power extraction technology, which reduces the size and weight while improving power supply reliability. It adopts a dual power extraction method of external high-voltage CT isolation power supply and high-voltage DC bus power extraction, ensuring mutual redundancy of power supplies and greatly improving power supply safety and reliability. Considering the high-potential floating characteristics of medium- and high-voltage direct-connected energy storage systems, the high-voltage box has been functionally expanded, eliminating the defects of low-voltage energy storage system high-voltage boxes that are not suitable for medium- and high-voltage direct-connected energy storage systems. Communication function, dry contact function, power input and output functions have been added; CAN to optical signal function has been added, which isolates the high- and low-voltage systems through optical signals to ensure safe signal transmission; the structure and panel of the medium- and high-voltage energy storage system have been designed to meet the specific application scenarios and structural layout and wiring requirements, and the high-voltage box has the characteristics of beautiful and compact appearance and complete functions.

[0102] The features described in the various embodiments of this specification can be substituted for or combined with each other. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0103] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0104] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-voltage box for a medium-high voltage direct-connected energy storage system, characterized in that, include: DC switch, battery management control unit (BCMU), redundant power supply, and CAN-to-optical module; The input terminal of the redundant power supply is connected to an AC power source through the AC / DC conversion unit of the high-voltage isolation CT. The input terminal of the redundant power supply is also connected to a high-voltage DC power supply through a high-voltage isolated DC / DC converter unit. The DC switch is located between the battery and the energy storage converter PCS in the energy storage system. The BCMU is used to control the on / off state of the DC switch; The output of the redundant power supply is the BCMU, as well as the power supply for the PCS core board and the battery management system (BMS) of the energy storage system. The BCMU communicates with the energy storage system via RS-485 and CAN communication. The CAN-to-optical module is used to convert CAN signals into optical signals; The BCMU communicates with the CAN-to-optical module; The CAN-to-optical module communicates with the optical-to-CAN module in the energy storage system; The optical-to-CAN module communicates with the Battery Management System (BAMS) in the energy storage system. The BAMS communicates with the energy management system (EMS) in the energy storage system. The CAN-to-optical module is powered by a first power supply, and the optical-to-CAN module and the BAMS are powered by a second power supply; the first power supply is located in the high-voltage box, and the second power supply is located in the energy storage system.

2. The high-voltage box of the medium-high voltage direct-connected energy storage system according to claim 1, characterized in that, Also includes: Current detection module; The current detection module is used to detect the battery current value of the energy storage system and transmit the battery current value to the BCMU.

3. The high-voltage box of the medium-high voltage direct-connected energy storage system according to claim 2, characterized in that, The BCMU is also used to receive the status feedback from the DC switch; and to determine the status parameters of the battery based on the battery current value, and to control the PCS in the energy storage system based on the status parameters.

4. The high-voltage box of the medium-high voltage direct-connected energy storage system according to any one of claims 1-3, characterized in that, Also includes: Terminal blocks for incoming and outgoing lines; The redundant power supply communicates with the outside world through the incoming and outgoing terminal blocks.

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