Energy storage valve sub-module, energy storage valve and energy storage station

Abstract

The present application belongs to the technical field of power electronics. Provided are an energy storage valve sub-module (100), an energy storage valve and an energy storage station. By means of a switch module (130), the energy storage valve sub-module (100) may disconnect a power module (120) from an electrical connection to the energy storage module (110), so as to form electrical isolation, such that the power module (120) is electrically disconnected from the energy storage module (110), thus eliminating the presence of a leakage current when components other than the energy storage module (110) in the energy storage valve are overhauled, and ensuring the personal safety of overhauling staff. By the same reasoning, when an energy storage module (110) side of the energy storage valve has a non-severe failure, insofar as the energy storage valve is locked, using the switch module (130) to separate the energy storage module (110) from a system will not affect the safe operation of the whole machine, thus effectively improving the availability of the system.

Description

Energy storage valve submodule, energy storage valve and energy storage station

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on June 28, 2023, with application number 202310779892.9 and invention name "Energy Storage Valve Submodule, Energy Storage Valve and Energy Storage Station", the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the field of power electronics technology, and in particular relates to an energy storage valve submodule, an energy storage valve, and an energy storage station. Background Art

[0003] Currently, market developments indicate that the application of high-voltage, direct-mounted energy storage systems is becoming increasingly widespread. Energy storage stations are widely used in transmission and distribution grids. As the application of energy storage stations continues to expand, market demand is also growing. When powering down a high-voltage, direct-mounted energy storage system for maintenance, due to its inherent characteristics, voltage accumulates due to the series connection of submodules. Even if the main circuit is disconnected from the high-voltage busbar, the voltage to ground of each submodule cannot be directly reduced to the voltage level of a single submodule, and the system remains high relative to ground. Furthermore, due to the voltage of the energy storage module, the voltage of the capacitors in the power module cannot be fully discharged to zero, resulting in leakage current in the system and compromising the safety of personnel performing maintenance. Furthermore, in the event of a non-critical fault on the energy storage module side, the conventional fault handling method is limited to electronic bypassing of the power module and activation of the bypass switch, necessitating a system shutdown for maintenance, resulting in low system availability.

[0004] Application Contents

[0005] In view of the above problems, the present application provides an energy storage valve submodule, an energy storage valve and an energy storage station, aiming to solve the problems of low maintenance safety and low system availability in related high-pressure direct-mounted energy storage systems.

[0006] In a first aspect, an embodiment of the present application provides an energy storage valve submodule, comprising an energy storage module, a power module, and a switch module; the power module is connected to the energy storage module through the switch module, or the power module is disconnected from the electrical connection with the energy storage module through the switch module, thereby forming electrical isolation.

[0007] In the technical solution of the embodiments of the present application, the energy storage valve submodule, through a switch module, can disconnect the power module from the energy storage module, achieving electrical isolation. This allows the energy storage system housing platform to be effectively grounded during maintenance of components outside the energy storage module, eliminating leakage current and ensuring the safety of maintenance personnel. Similarly, in the event of a non-critical fault on the energy storage module side, the switch module can be used to isolate the energy storage module from the system while the energy storage valve is locked, without affecting the safe operation of the entire system, effectively improving system availability.

[0008] In some embodiments, the switch module includes a first switch group, and the first switch group is connected to the positive terminal and the negative terminal of the power module and the positive electrode and the negative electrode of the energy storage module.

[0009] In the technical solution of the embodiment of the present application, a centralized control device is adopted to improve the flexibility of the switch module control.

[0010] In some embodiments, the first switch group includes a first switch and a second switch;

[0011] The first switch is connected between the positive terminal of the power module and the positive terminal of the energy storage module;

[0012] The second switch is connected between the negative terminal of the power module and the negative terminal of the energy storage module.

[0013] In the technical solution of the embodiment of the present application, the power module and the energy storage module can be connected by controlling the first switch and the second switch respectively, thereby removing the electrical connection between the power module and the energy storage module and simplifying the circuit design.

[0014] In some embodiments, the first switch and the second switch each comprise a load switch.

[0015] In the technical solution of the embodiment of the present application, the load switch can disconnect the current while meeting the electrical isolation requirement. The disconnection speed of the load switch can generally reach tens of milliseconds, and the response is relatively fast. However, the response speed and protection effect are lower than those of the fuse in the energy storage module. Therefore, it plays the role of backup protection and redundant protection. When the fuse on the energy storage module side fails to provide successful protection, the energy storage module is protected.

[0016] In some embodiments, the first switch and the second switch each comprise an isolating switch.

[0017] In the technical solution of the embodiment of the present application, the isolating switch is, for example, an isolator or an isolating knife switch, wherein the isolating switch can be of a type that can disconnect the load current, and can disconnect the electrical connection between the power module and the energy storage module; or it can be of a type that cannot disconnect the load current, and then the power module can be modulated so that the current between the power module and the energy storage module is close to 0 (the transistor of the power module may have a weak leakage current, but it can disconnect the load current) to achieve current disconnection, and can also disconnect the electrical connection between the power module and the energy storage module to achieve reliable electrical isolation.

[0018] In some embodiments, the system further includes a second switch group for disconnecting the load current, wherein the second switch group is connected to the first switch group.

[0019] In the technical solution of the embodiment of the present application, when the isolating switch in the first switch group adopts the type of non-disconnectable load current, a second switch group will be set to disconnect the load current, thereby releasing the electrical connection between the power module and the energy storage module and achieving reliable electrical isolation.

[0020] In some embodiments, the second switch group includes a solid-state circuit breaker connected in series with the first switch or the second switch.

[0021] In the technical solution of the embodiment of the present application, in order to achieve reliable isolation, a solid-state circuit breaker and an isolating switch are used in combination. The solid-state circuit breaker is used to reduce the loop current to near 0, disconnecting the load current, and then the isolating switch is used to isolate the system, disconnecting the electrical connection between the power module and the energy storage module, and achieving reliable electrical isolation.

[0022] In some embodiments, the second switch group includes:

[0023] Two circuit breakers, the two circuit breakers are connected in series with the first switch and the second switch respectively; or

[0024] Two relays, the two relays are connected in series with the first switch and the second switch respectively;

[0025] In the technical solution of the embodiment of the present application, in order to achieve reliable isolation, a circuit breaker or relay is used in conjunction with an isolating switch. The circuit breaker or relay is used to cut off the current in the loop, and then the isolating switch is disconnected to release the electrical connection between the power module and the energy storage module, thereby achieving reliable electrical isolation.

[0026] In some embodiments, the power module serves as the second switch group.

[0027] In the technical solution of the embodiment of the present application, in order to achieve reliable isolation, the power module is directly modulated so that the loop current of the energy storage valve submodule is close to 0, thereby disconnecting the load current. The system is then isolated using an isolating switch to release the electrical connection between the power module and the energy storage module. This solution is simpler and has lower costs.

[0028] In some embodiments, the power module includes a first switching element and an energy storage element connected in parallel to the first switching element, and the energy storage element is connected in parallel to the energy storage module through the switching module.

[0029] In the technical solution of the embodiment of the present application, when the power module is connected to the energy storage module, the energy storage element can be charged first, thereby reducing the impact of large current on the first switching element and improving the reliability of the energy storage valve submodule.

[0030] In the technical solution of the embodiment of the present application, the power module includes a half-bridge circuit or a full-bridge circuit.

[0031] By adopting the above solution, flexible configuration of the power module is achieved, and the design flexibility of the energy storage valve submodule is improved.

[0032] In some embodiments, a controller is also included, which is connected to the power module and the switch module. The controller is used to output a drive signal and a control signal. The drive signal is used to drive the power module to turn on and off, and the control signal is used to control the switch module to turn on and off.

[0033] In the technical solution of the embodiment of the present application, both the power module and the switch module can be controlled online by a controller, thereby realizing the intelligence and automation of the energy storage valve submodule.

[0034] In a second aspect, an embodiment of the present application further provides an energy storage valve, which includes the energy storage valve submodule as described above.

[0035] In the technical solution of the embodiments of the present application, each energy storage valve submodule in the energy storage valve can electrically isolate and disconnect the power module from the energy storage module through a switch module, thereby electrically decoupling the power module from the energy storage module. This prevents leakage current when repairing components other than the energy storage module in the energy storage valve, thereby ensuring the personal safety of maintenance personnel. Similarly, if a non-critical fault occurs on the energy storage module side of the energy storage valve, the switch module can be used to disconnect the energy storage module from the system while the energy storage valve is locked, without affecting the safe operation of the entire system and improving system availability.

[0036] In a third aspect, an embodiment of the present application further provides an energy storage station, which includes the energy storage valve submodule as described above.

[0037] In the technical solution of the embodiments of the present application, each energy storage valve submodule in the energy storage station can electrically isolate and disconnect the power module from the energy storage module through a switch module, thereby electrically decoupling the power module from the energy storage module. This prevents leakage current when repairing components other than the energy storage module in the energy storage station, thereby ensuring the personal safety of maintenance personnel. Similarly, if a non-critical fault occurs on the energy storage module side of the energy storage station, the switch module can be used to disconnect the energy storage module from the system while the energy storage station is locked, without affecting the safe operation of the entire system and improving system availability.

[0038] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustration purposes only and are not to be construed as limiting the present application. The same reference numerals are used throughout the drawings to denote the same components. In the drawings:

[0040] FIG1 is a schematic structural diagram of an energy storage valve submodule provided in one embodiment of the present application;

[0041] FIG2 is another structural schematic diagram of an energy storage valve submodule provided in one embodiment of the present application;

[0042] FIG3 is another structural schematic diagram of an energy storage valve submodule provided in one embodiment of the present application;

[0043] FIG4 is another structural schematic diagram of an energy storage valve submodule provided in one embodiment of the present application;

[0044] FIG5 is another structural schematic diagram of an energy storage valve submodule provided in one embodiment of the present application;

[0045] FIG6 is a schematic structural diagram of a power module in an energy storage valve submodule provided in an embodiment of the present application;

[0046] FIG7 is a schematic structural diagram of a power module in an energy storage valve submodule provided in one embodiment of the present application;

[0047] FIG8 is a structural diagram of an MMC type AC direct-mounted energy storage system provided in one embodiment of the present application;

[0048] FIG9 is a structural diagram of a DC direct-mounted energy storage system provided in one embodiment of the present application;

[0049] FIG10 is a structural diagram of an AC direct-mounted energy storage system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0050] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0052] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0053] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0054] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0055] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0056] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0057] High-voltage direct-mount energy storage systems are primarily categorized into several technical approaches, including MMC (Modular Multilevel Converter) AC direct-mount energy storage systems, DC direct-mount energy storage systems, and AC cascade energy storage systems. Compared to traditional energy storage technologies, direct-mount energy storage systems offer higher voltage levels, larger capacities, and enhanced grid regulation and support capabilities, making them of significant research significance for new power systems primarily based on renewable energy.

[0058] However, current high-voltage direct-mounted energy storage systems still face several challenges. For example, when power is turned off for maintenance, the inherent characteristics of high-voltage direct-mounted energy storage systems can lead to voltage accumulation due to the series connection of the energy storage valve submodules. Even if the main circuit is disconnected from the high-voltage busbar, the voltage to ground of each energy storage valve submodule cannot be directly reduced to the voltage level of a single submodule, and the system remains high to ground. Furthermore, due to the voltage of the energy storage modules, if the capacitors in the power modules and the energy storage modules are not electrically decoupled, the capacitor voltage cannot be completely discharged to zero, resulting in leakage current in the system and compromising safety for personnel accessing the system. Furthermore, in the event of a non-critical fault on the energy storage module side, the only means of fault resolution are electronic bypass of the power module and activation of the bypass switch. Fault isolation is limited, and electrical isolation of the fault point is impossible. Furthermore, in the event of failure of the electronic bypass or bypass switch, the system must be shut down for maintenance, resulting in low system availability.

[0059] According to some embodiments of the present application, referring to FIG1 , FIG1 shows a schematic structural diagram of an energy storage valve submodule provided in an embodiment of the present application. For ease of illustration, only parts related to the present embodiment are shown, which are described in detail as follows:

[0060] The energy storage valve submodule 100 includes an energy storage module 110 , a power module 120 and a switch module 130 ; the power module 120 is connected to the energy storage module 110 through the switch module 130 , or the power module 120 is electrically isolated and disconnected from the energy storage module 110 through the switch module 130 .

[0061] Among them, the main components of the energy storage module 110 include energy storage devices, and the number of energy storage devices is at least one. The energy storage device can be in various forms, including one or more of the energy storage methods such as electrochemical energy storage devices (such as batteries), supercapacitors, flywheel energy storage, compressed air energy storage, and superconducting energy storage. The power module 120 is electrically disconnected from the energy storage module 110 through the switch module 130 to form electrical isolation. Specifically, the switch module 130 or the power module 120 can form an electrical breakpoint between the power module 120 and the energy storage module 110 to disconnect the load current, thereby releasing the electrical connection between the power module 120 and the energy storage module 110. If maintenance is required or the energy storage module 110 fails, the power module 120 can be effectively electrically isolated and disconnected from the energy storage module 110, so that the energy storage system casing platform can be effectively grounded. When repairing components other than the energy storage module 110, there will be no leakage current, which can ensure the personal safety of the repair personnel. In the event of a system fault such as relay welding and adhesion, which makes it impossible to effectively disconnect the electrical connection, this isolation method can be used to safely repair and replace the relay or other equipment that causes the problem of being unable to disconnect. Similarly, in the event of a non-serious fault on the energy storage module 110 side, the energy storage module 110 can be separated from the system composed of the energy storage valve submodule 100 without affecting the safe operation of the entire machine, which can effectively improve the availability of the system. After a minor fault occurs in the energy storage module 110, temporary measures such as electronic bypass and bypass switch operation are used in the absence of an isolation switch. If problems such as the power switch being turned on occur, the nature of the fault is likely to change, resulting in serious faults such as battery short circuits. After introducing this isolation method, such problems are effectively avoided, and the fault can be prevented from further development and serious consequences can be avoided.

[0062] According to some embodiments of the present application, referring again to FIG. 1 , the switch module 130 includes a first switch group. The first switch group is connected to the positive and negative terminals of the power module 120 and the positive and negative terminals of the energy storage module 110. The entire switch module can have a single operating mechanism, i.e., integrated into a single device and utilizing a single control system, enabling more flexible control. It is understood that independently operated switches can also be employed to achieve electrical isolation.

[0063] According to some embodiments of the present application, referring to FIG. 2 , FIG. 2 shows a schematic structural diagram of an energy storage valve submodule provided in an embodiment of the present application. For ease of illustration, only portions related to the present embodiment are shown, as detailed below:

[0064] The first switch group includes a first switch S1 and a second switch S2; the first switch S1 is connected between the positive terminal of the power module 120 and the positive terminal of the energy storage module 110; the second switch S2 is connected between the negative terminal of the power module 120 and the negative terminal of the energy storage module 110.

[0065] In the technical solution of the embodiment of the present application, the power module 120 and the energy storage module 110 can be connected to each other through the first switch S1 and the second switch S2, respectively, so that the control is reliable. While the electrical connection between the power module 120 and the energy storage module 110 is released, the circuit design is simplified.

[0066] In some embodiments, the first switch S1 and the second switch S2 each comprise a load switch, which may also be referred to as a load isolation switch, and is a type of isolation switch capable of cutting off load current.

[0067] In the technical solution of the embodiment of the present application, the load switch can disconnect the load current while meeting the electrical isolation requirement. The disconnection speed of the load switch can generally reach tens of milliseconds, and the response is relatively fast. However, the response speed and protection effect are lower than those of the fuse in the energy storage module 110. Therefore, it plays the role of backup protection and redundant protection. When the fuse on the energy storage module 110 side fails to provide successful protection, the energy storage module 110 is protected.

[0068] In some embodiments, the first switch S1 and the second switch S2 both include isolating switches, such as isolators and isolating switches.

[0069] In the technical solution of the embodiment of the present application, the isolating switch can be of a type that can disconnect the load current, and can disconnect the electrical connection between the power module 120 and the energy storage module 110; or it can be of a type that cannot disconnect the load current, in which case other devices can be used, such as modulating the power module 120 so that the current between the power module 120 and the energy storage module 110 is close to 0 (because the transistor in the power module 120 may have leakage current, but it can meet the disconnection compliance current) to achieve load current disconnection, and can also disconnect the electrical connection between the power module 120 and the energy storage module 110, thereby achieving reliable electrical isolation.

[0070] According to some embodiments of the present application, referring to FIG3 , FIG3 shows a schematic structural diagram of an energy storage valve submodule provided in an embodiment of the present application. For ease of illustration, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0071] In some embodiments, the switch module 130 further includes a second switch group 140 for disconnecting the load current, and the second switch group 140 is connected to the switch module 130 .

[0072] For example, when the isolating switch in the switch module 130 is of the type that cannot disconnect the load current, it is necessary to further set a second switch group 140 to disconnect the load current, thereby releasing the electrical connection between the power module 120 and the energy storage module 110 and achieving reliable electrical isolation.

[0073] According to some embodiments of the present application, referring to FIG4 , FIG4 shows a schematic structural diagram of an energy storage valve submodule provided in an embodiment of the present application. For ease of illustration, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0074] In some embodiments, the second switch group 140 includes a solid-state circuit breaker S3 connected in series with the first switch S1 or the second switch S2.

[0075] Solid-state circuit breaker S3 is a fast-acting protection device that uses power electronics to suppress the rise of short-circuit current within microseconds and divert the short-circuit current out of the circuit, effectively reducing the circuit current to near zero. The response speed and protection capabilities of solid-state circuit breaker S3 are far superior to the fuses typically used in energy storage systems. Understandably, if solid-state circuit breaker S3 is used to protect the circuit, no fuses are required within the energy storage system, greatly reducing the complexity of fuse configuration. It also avoids the tedious process of replacing fuses after a system short circuit blows. Even if fuses are still configured in the energy storage system, they serve only as backup and redundant protection for solid-state circuit breaker S3, eliminating the reliance on fuses as the primary protection method.

[0076] In the technical solution of the embodiment of the present application, in order to achieve reliable decoupling, a solid-state circuit breaker S3 and an isolating switch are used in combination. The solid-state circuit breaker S3 is used to reduce the loop current to near 0, and then the isolating switch is used to isolate the system, thereby releasing the electrical connection between the power module 120 and the energy storage module 110 and achieving reliable electrical isolation.

[0077] According to some embodiments of the present application, referring to FIG5 , FIG5 shows a schematic structural diagram of an energy storage valve submodule provided in an embodiment of the present application. For ease of illustration, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0078] In some embodiments, the second switch group 140 includes two circuit breakers or two relays, as shown in S4 and S5 in FIG5 . Specifically, the second switch group 140 includes two circuit breakers, which are connected in series with the first switch S1 and the second switch S2, respectively; the second switch group 140 includes two relays, which are connected in series with the first switch S1 and the second switch S2, respectively.

[0079] Use an isolating switch in conjunction with a device capable of interrupting the load current. Circuit breakers, contactors, and other devices can interrupt the load current in a circuit, but they cannot provide reliable electrical isolation. Therefore, an isolating switch is used in conjunction with other devices, such as circuit breakers and contactors. One device interrupts the load current, while the isolating switch provides reliable electrical isolation.

[0080] In the technical solution of the embodiment of the present application, in order to achieve reliable isolation, a circuit breaker or relay is used in conjunction with an isolating switch. The circuit breaker or relay is used to cut off the load current in the loop, and then the isolating switch is used to isolate the system, thereby achieving complete decoupling and reliable isolation of the power module 120 and the energy storage module 110.

[0081] According to some embodiments of the present application, with continued reference to FIG2 , in some embodiments, the second switch group 140 includes a power module 120 .

[0082] In the technical solution of the embodiment of the present application, the power module 120 in the energy storage valve submodule 100 is directly modulated so that the loop current of the energy storage valve submodule 100 is close to 0, thereby cutting off the load current. The system is then isolated using an isolating switch to release the electrical isolation between the power module 120 and the energy storage module 110. This solution is simpler and has lower costs.

[0083] In some embodiments, the power module 120 includes a first switching element and an energy storage element connected in parallel to the first switching element. The energy storage element is connected in parallel to the energy storage module 110 through the switching module 130 .

[0084] There may be multiple first switching elements, connected in series and / or in parallel, and the energy storage element is connected in parallel with the multiple first switching elements connected in series and / or in parallel. In a specific implementation, the multiple first switching elements connected in series and / or in parallel comprise a full-bridge circuit or a half-bridge circuit. When connecting the power module 120 to the energy storage module 110, the energy storage element can be charged first, thereby reducing the impact of high current on the first switching element and improving the reliability of the energy storage valve submodule 100.

[0085] In the technical solutions of the embodiments of the present application, power module 120 comprises a half-bridge circuit or a full-bridge circuit. It should be noted that a half-bridge circuit is a power circuit comprising two switching transistors, while a full-bridge circuit is a power circuit comprising four switching transistors. A half-bridge circuit is low-cost and simple; a full-bridge circuit is high-cost and relatively complex. However, a full-bridge circuit exhibits less interference and is more reliable than a half-bridge circuit. This enables flexible configuration of power module 120 and increases the design flexibility of the energy storage valve submodule 100.

[0086] According to some embodiments of the present application, referring to FIG6 , FIG6 shows a schematic structural diagram of a power module in an energy storage valve submodule provided in an embodiment of the present application. For ease of illustration, only portions related to the present embodiment are shown, as detailed below:

[0087] The full-bridge circuit includes a first switch tube T1, a second switch tube T2, a third switch tube T3, a fourth switch tube T4, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4 and a first capacitor C1;

[0088] The input end of the first switching transistor T1, the cathode of the first diode D1, the input end of the third switching transistor T3, the cathode of the third diode D3, and the first end of the first capacitor C1 collectively serve as a first positive terminal of the full-bridge circuit; the output end of the second switching transistor T2, the anode of the second diode D2, the output end of the fourth switching transistor T4, the anode of the fourth diode D4, and the second end of the first capacitor C1 collectively serve as a first negative terminal of the full-bridge circuit; the output end of the third switching transistor T3, the anode of the third diode D3, the input end of the fourth switching transistor T4, and the cathode of the fourth diode D4 collectively serve as a second positive terminal of the full-bridge circuit; the output end of the first switching transistor T1, the anode of the first diode D1, the input end of the second switching transistor T2, and the cathode of the second diode D2 collectively serve as a second negative terminal of the full-bridge circuit.

[0089] Among them, the first positive terminal of the full-bridge circuit is the first positive terminal of the power module 120; the second positive terminal of the full-bridge circuit is the second positive terminal of the power module 120; the first negative terminal of the full-bridge circuit is the first negative terminal of the power module 120; and the second negative terminal of the full-bridge circuit is the second negative terminal of the power module 120.

[0090] It should be noted that the above-mentioned switching transistors include triodes, field effect transistors and insulated gate bipolar transistors.

[0091] Specifically, the full-bridge circuit operates in the first switching state as follows: the anode of the third diode D3 is connected to the first DC power output from the grid, the cathode of the third diode D3 outputs the first DC power to the energy storage module 110, the anode of the second diode D2 is connected to the first DC power charged by the energy storage module 110, and the cathode of the second diode D2 outputs the first DC power charged by the energy storage module 110 to the grid.

[0092] The full-bridge circuit operates in the second switching state as follows: the input end of the third switch tube T3 is connected to the second DC power output from the positive electrode of the energy storage module 110, the output end of the third switch tube T3 outputs the second DC power to the grid, the input end of the second switch tube T2 is connected to the second DC power fed back from the grid, and the output end of the second switch tube T2 outputs the fed-back second DC power to the negative electrode of the energy storage module 110.

[0093] The full-bridge circuit operates in the first cut-off state as follows: the input end of the fourth switch tube T4 is connected to the first DC power output by the grid, the output end of the fourth switch tube T4 outputs the first DC power to the anode of the second diode D2, and the cathode of the second diode D2 outputs the first DC power.

[0094] Specifically, the full-bridge circuit operates in the second cut-off state as follows: the anode of the first diode D1 is connected to the third DC power, the cathode of the first diode D1 outputs the third DC power to the input end of the third switch tube T3, and the output end of the third switch tube T3 outputs the third DC power.

[0095] The above full-bridge circuit can self-eliminate DC faults and can be used in scenarios with high input voltage.

[0096] According to some embodiments of the present application, referring to FIG7 , FIG7 shows a schematic structural diagram of a power module in an energy storage valve submodule provided in an embodiment of the present application. For ease of explanation, only the parts related to the present embodiment are shown, which are described in detail as follows: The half-bridge circuit includes a fifth switch tube T5, a sixth switch tube T6, a fifth diode D5, a sixth diode D6, and a second capacitor C2.

[0097] The input end of the fifth switch tube T5, the cathode of the fifth diode D5, and the first end of the second capacitor C2 collectively serve as the first positive terminal of the half-bridge circuit; the output end of the sixth switch tube T6, the anode of the sixth diode D6, and the second end of the second capacitor C2 collectively serve as the first negative terminal and the second negative terminal of the half-bridge circuit; the output end of the fifth switch tube T5, the anode of the fifth diode D5, the input end of the sixth switch tube T6, and the cathode of the sixth diode D6 collectively serve as the second positive terminal of the half-bridge circuit.

[0098] Among them, the first positive terminal of the half-bridge circuit is the first positive terminal of the power module 120; the second positive terminal of the half-bridge circuit is the second positive terminal of the power module 120; the first negative terminal of the half-bridge circuit is the first negative terminal of the power module 120; and the second negative terminal of the half-bridge circuit is the second negative terminal of the power module 120.

[0099] It should be noted that the above-mentioned switching transistors include triodes, field effect transistors and insulated gate bipolar transistors.

[0100] Specifically, the half-bridge circuit operates in the first switching state as follows: the anode of the fifth diode D5 is connected to the first DC power output from the grid, the cathode of the fifth diode D5 outputs the first DC power to the anode of the energy storage module 110, and the cathode of the energy storage module 110 outputs the first DC power charged by the energy storage module 110 to the grid.

[0101] Specifically, the half-bridge circuit operates in the second switching state as follows: the input end of the fifth switch tube T5 is connected to the second DC power output by the positive electrode of the energy storage module 110, the output end of the fifth switch tube T5 outputs the second DC power to the grid, and the grid feeds the second DC power back to the negative electrode of the energy storage module 110.

[0102] Specifically, the half-bridge circuit operates in the first cut-off state as follows: the input end of the sixth switch tube T6 is connected to the first DC power output by the grid, and the output end of the sixth switch tube T6 outputs the first DC power.

[0103] Specifically, the above-mentioned half-bridge circuit operates in the second cut-off state as follows: the anode of the sixth diode D6 is connected to the third direct current, and the cathode of the sixth diode D6 outputs the third direct current.

[0104] The above half-bridge circuit has a simple structure and low cost.

[0105] In some embodiments, the energy storage valve submodule 100 also includes a controller, which is connected to the power module 120 and the switch module 130. The controller is used to output a drive signal and a control signal. The drive signal is used to drive the power module 120 to be turned on and off, and the control signal is used to control the switch module 130 to be turned on and off.

[0106] The controller can also output a drive signal with a preset duty cycle to modulate the power module 120, causing the current between the power module 120 and the energy storage module 110 to change, such as approaching zero to disconnect the load current, or achieving a duty cycle of 100% to fully conduct the current. The controller outputs multiple control signals, generally at high and low levels, to drive the individual switches in the switch module 130 on and off.

[0107] In some embodiments, the controller includes a submodule controller (SMC). The SMC is used to monitor the operating status of the energy storage valve submodule 100, receive control information from the energy storage valve's valve base controller (VBC), and transmit the status of the energy storage valve submodule 100 to the VBC. Furthermore, when the SMC detects a fault in the energy storage valve submodule 100, it controls the power module 120 and the switch module 130 to shut down, bypassing the energy storage module 110, and transmits fault information to the VBC, ensuring that other submodules continue to operate normally.

[0108] In the technical solution of the embodiment of the application, both the power module 120 and the switch module 130 can be controlled online by a controller, thereby realizing the intelligence and automation of the energy storage valve submodule.

[0109] According to some embodiments of the present application, the present application further provides an energy storage valve, including the above-mentioned energy storage valve submodule 100; the energy storage valve submodule 100 can be connected in series to a power grid.

[0110] Because the energy storage valve includes the energy storage valve submodule 100 of any of the above solutions, each energy storage valve submodule 100 can electrically isolate and disconnect the power module 120 from the energy storage module 110 through the switch module 130, thereby electrically decoupling the power module 120 from the energy storage module 110. This prevents leakage current when repairing components other than the energy storage module 110 in the energy storage valve, thereby ensuring the personal safety of maintenance personnel. Similarly, if a non-critical fault occurs on the energy storage module 110 side of the energy storage valve, the switch module 130 can be used to disconnect the energy storage module 110 from the system while the energy storage valve is locked, without affecting the safe operation of the entire system and improving system availability.

[0111] According to some embodiments of the present application, the present application further provides an energy storage station, comprising the energy storage valve submodule 100 of any of the above solutions.

[0112] It should be noted that the energy storage station includes a plurality of energy storage valve submodules 100. The plurality of energy storage valve submodules 100 are connected in series and / or in parallel.

[0113] Because the energy storage station includes the energy storage valve submodule 100 of any of the above solutions, the power module 120 can be electrically decoupled from the energy storage module 110 during maintenance, ensuring the personal safety of maintenance personnel. Similarly, if a non-critical fault occurs on the energy storage module 110 side of the energy storage station, the switch module 130 can be used to disconnect the energy storage module 110 from the system while the energy storage station is locked, without affecting the safe operation of the entire system and improving system availability.

[0114] Figure 8 shows a schematic diagram of the structure of an MMC-type AC direct-mounted energy storage system applicable to an energy storage station according to an embodiment of the present application. As shown in Figure 8, the MMC-type AC direct-mounted energy storage system includes six converter bridge arm groups, which include a first converter bridge arm group 810, a second converter bridge arm group 820, a third converter bridge arm group 830, a fourth converter bridge arm group 840, a fifth converter bridge arm group 850, and a sixth converter bridge arm group 860. The first converter arm group 810 and the second converter arm group 820 are connected in series, the third converter arm group 830 and the fourth converter arm group 840 are connected in series, and the fifth converter arm group 850 and the sixth converter arm group 860 are connected in series. The connection point between the first converter arm group 810 and the second converter arm group 820, the connection point between the third converter arm group 830 and the fourth converter arm group 840, and the connection point between the fifth converter arm group 850 and the sixth converter arm group 860 are respectively connected to the three-phase AC power grid. Each converter arm group is composed of N energy storage valve submodules 801 and other auxiliary devices connected in series, where N is a positive integer. As shown in Figure 8, the N energy storage valve submodules 801 include energy storage valve submodules 801_1, 801_2, ..., 801_N. The auxiliary devices can be starting devices, / or switching devices, / or line protection devices, and / or sampling devices. For example, the auxiliary device may be the reactors L1 to L6 described in FIG. 8 .

[0115] FIG9 shows a schematic structural diagram of a DC direct-mounted energy storage system according to an embodiment of the present application. As shown in FIG9 , the DC direct-mounted energy storage system, also known as an energy storage valve, is composed of n energy storage valve submodules SM connected in series with other auxiliary equipment, where n is a positive integer. As shown in FIG9 , the n energy storage valve submodules SM include energy storage submodules SM#1, ..., SM#n-1, and SM#n. The auxiliary equipment may be a starting device and / or a switching device and / or a line protection device and / or a sampling device. For example, the auxiliary equipment may include a fast switch S11 between the positive pole and the positive DC bus of the n energy storage valve submodules SM shown in FIG9 , an isolation knife S12, a grounding knife S13 connected to both ends of the fast switch S11 and the isolation knife S12, a current transformer CT1, and a current-limiting reactor L7; an isolation knife S14 between the negative pole and the positive DC bus of the n energy storage valve submodules SM, a grounding knife S15 connected to both ends of the isolation knife S14, and a current transformer CT2. In addition, a voltage transformer VT1 is also provided on the positive DC bus.

[0116] FIG10 shows a schematic structural diagram of an AC direct-mounted energy storage system that can be applied to an energy storage station according to an embodiment of the present application. As shown in FIG10 , the AC direct-mounted energy storage system includes three converter bridge arm groups, and the three converter bridge arm groups (i.e., energy storage valves) include a first energy storage valve 1110, a second energy storage valve 1120, and a third energy storage valve 1130. The first energy storage valve 1110, the second energy storage valve 1120, and the third energy storage valve 1130 are respectively connected to a three-phase AC power grid. Each energy storage valve is composed of N energy storage valve submodules 1101 and other auxiliary devices connected in series, where N is a positive integer. As shown in FIG10 , the N energy storage valve submodules 1101 include energy storage valve submodules 1101_1, 1101_2, ..., 1101_N. The auxiliary device can be a starting device and / or a switching device and / or a line protection device and / or a sampling device. For example, the auxiliary device can be the reactor described in FIG10 .

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A storage valve submodule, wherein: It includes an energy storage module, a power module and a switch module; the power module is connected to the energy storage module through the switch module, or the power module is disconnected from the electrical connection with the energy storage module through the switch module to form electrical isolation.

2. The energy storage valve submodule according to claim 1, wherein: The switch module includes a first switch group, and the first switch group is connected to the positive terminal and the negative terminal of the power module and the positive electrode and the negative electrode of the energy storage module.

3. The energy storage valve submodule according to claim 2, wherein: The first switch group includes a first switch and a second switch; The first switch is connected between the positive terminal of the power module and the positive terminal of the energy storage module; The second switch is connected between the negative terminal of the power module and the negative terminal of the energy storage module.

4. The energy storage valve submodule according to claim 3, wherein: The first switch and the second switch include load switches.

5. The energy storage valve submodule according to claim 3, wherein: The first switch and the second switch include isolation switches.

6. The energy storage valve submodule according to claim 5, wherein: The switch module further includes a second switch group for disconnecting load current, and the second switch group is connected to the first switch group.

7. The energy storage valve submodule according to claim 6, wherein: The second switch group includes a solid-state circuit breaker connected in series with the first switch or the second switch.

8. The energy storage valve submodule according to claim 6, wherein: The second switch group includes: Two circuit breakers are respectively connected in series with the first switch and the second switch.

9. The energy storage valve submodule according to claim 6, wherein: The second switch group includes: Two relays are respectively connected in series with the first switch and the second switch.

10. The energy storage valve submodule according to claim 6, wherein: The power module serves as the second switch group for disconnecting load current.

11. The energy storage valve submodule according to any one of claims 1 to 10, wherein: The power module includes a first switch element and an energy storage element connected in parallel to the first switch element. The energy storage element is connected in parallel to the energy storage module through the switch module.

12. The energy storage valve submodule according to any one of claims 1 to 11, wherein: The power module includes a half-bridge circuit or a full-bridge circuit.

13. The energy storage valve submodule according to any one of claims 1 to 12, wherein: It also includes a controller, which is connected to the power module and the switch module. The controller is used to output a drive signal and a control signal. The drive signal is used to drive the power module to turn on and off, and the control signal is used to control the switch module to turn on and off.

14. A storage valve, wherein: The energy storage valve comprises an energy storage valve submodule as described in any one of claims 1 to 13.

15. An energy storage station, wherein: The energy storage station comprises the energy storage valve submodule according to any one of claims 1 to 13.

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