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

Abstract

The invention belongs to the technical field of power electronics, and provides an energy storage valve sub-module, an energy storage valve and an energy storage station, the energy storage valve sub-module can disconnect electrical connection between a power module and an energy storage module through a switch module to form electrical isolation, so that the electrical connection between the power module and the energy storage module is released, and the energy storage station is protected. When parts except the energy storage module in the energy storage valve are overhauled, leakage current does not exist, and the personal safety of maintainers can be guaranteed. Similarly, under the condition that the energy storage module side of the energy storage valve has a non-serious fault, on the premise that the energy storage valve is locked, the energy storage module is separated from the system through the switch module, safe operation of the whole machine is not affected, and the availability rate of the system can be effectively increased.

Description

Technical Field

[0001] 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

[0002] At present, from the perspective of market development, the application of high-voltage direct-mounted energy storage systems is becoming more and more widespread. Energy storage stations are widely used in the field of transmission and distribution networks. With the continuous expansion of the application field of energy storage stations, the market demand is also constantly expanding.

[0003] When the high-voltage direct-mounted energy storage system is being overhauled, it is necessary to power off the system. Due to the characteristics of the high-voltage direct-mounted energy storage system, the voltage will accumulate due to the series connection of the sub-modules. Even if the main circuit is disconnected from the high-voltage bus, the voltage of each sub-module to the ground cannot be directly reduced to the voltage level of a single sub-module, and the system still presents high voltage to the ground. In addition, due to the existence of the energy storage module voltage, the voltage of the capacitor in the power module cannot be completely discharged and reduced to 0, resulting in leakage current in the system, and the safety of personnel on-board maintenance is very low. Furthermore, in the event of a non-serious fault on the energy storage module side, the fault handling means of the related technology are only the power module electronic bypass and bypass switch action, and the system has to be shut down for maintenance, resulting in low system availability. Summary of the invention

[0004] 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.

[0005] 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 to form electrical isolation.

[0006] In the technical solution of the embodiment of the present application, the energy storage valve submodule can disconnect the power module from the energy storage module and the electrical connection with the energy storage module through the switch module to form electrical isolation. When repairing components other than the energy storage module, the energy storage system housing platform can be effectively grounded, so there will be no leakage current, and the personal safety of the maintenance personnel can be guaranteed. Similarly, in the case of a non-serious fault on the energy storage module side, the energy storage module is separated from the system by using a switch module under the premise of locking the energy storage valve, without affecting the safe operation of the entire machine, and the availability of the system can be effectively improved.

[0007] 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.

[0008] In the technical solution of the embodiment of the present application, a centralized control device is used to improve the flexibility of switch module control.

[0009] In some embodiments, the first switch group includes a first switch and a second switch;

[0010] The first switch is connected between the positive terminal of the power module and the positive terminal of the energy storage module;

[0011] The second switch is connected between the negative terminal of the power module and the negative terminal of the energy storage module.

[0012] In the technical solution of the embodiment of the present application, the power module and the energy storage module can be connected to each other through the first switch and the second switch, which simplifies the circuit design while releasing the electrical connection between the power module and the energy storage module.

[0013] In some embodiments, the first switch and the second switch each include a load switch.

[0014] In the technical solution of the embodiment of the present application, the load switch can disconnect the current and meet the electrical isolation at the same time. The disconnection speed of the load switch can generally reach tens of milliseconds, and the response is fast. However, the response speed and protection effect are lower than 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 cannot successfully protect, the energy storage module is protected.

[0015] In some embodiments, the first switch and the second switch each comprise an isolation switch.

[0016] 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 release 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 release the electrical connection between the power module and the energy storage module to achieve reliable electrical isolation.

[0017] In some embodiments, the system further includes a second switch group for disconnecting load current, wherein the second switch group is connected to the first switch group.

[0018] In the technical solution of the embodiment of the present application, when the isolating switch in the first switch group is of the type that cannot disconnect the 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.

[0019] In some embodiments, the second switch group includes a solid-state circuit breaker connected in series with the first switch or the second switch.

[0020] 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, disconnect the load current, and then the isolating switch is used to isolate the system, release the electrical connection between the power module and the energy storage module, and achieve reliable electrical isolation.

[0021] In some embodiments, the second switch group includes:

[0022] Two circuit breakers, the two circuit breakers are respectively connected in series with the first switch and the second switch; or

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

[0024] 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 circuit, 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.

[0025] In some embodiments, the power module serves as the second switch group.

[0026] 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, and then the system is isolated by 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 cost.

[0027] In some embodiments, the power module includes a first switch element and an energy storage element connected in parallel to the first switch element, and the energy storage element is connected in parallel to the energy storage module through the switch module.

[0028] 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.

[0029] In the technical solution of the embodiment of the present application, the power module includes a half-bridge circuit or a full-bridge circuit.

[0030] By adopting the above solution, flexible configuration of the power module is achieved, and the flexibility of the design of the energy storage valve submodule is improved.

[0031] 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.

[0032] 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.

[0033] In a second aspect, an embodiment of the present application further provides an energy storage valve, which includes an energy storage valve submodule as described above.

[0034] In the technical solution of the embodiment 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 the switch module, so that the power module and the energy storage module are electrically decoupled. When repairing components other than the energy storage module in the energy storage valve, there will be no leakage current, thereby ensuring the personal safety of the repair personnel. Similarly, if a non-serious fault occurs on the energy storage module side of the energy storage valve, the switch module is used to separate the energy storage module from the system under the premise that the energy storage valve is locked, which does not affect the safe operation of the entire machine and improves the system availability.

[0035] 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.

[0036] In the technical solution of the embodiment 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 the switch module, so that the power module and the energy storage module are electrically decoupled. When repairing components other than the energy storage module in the energy storage station, there will be no leakage current, ensuring the personal safety of the maintenance personnel. Similarly, if a non-serious fault occurs on the energy storage module side of the energy storage station, the switch module is used to separate the energy storage module from the system under the premise of locking the energy storage station, which does not affect the safe operation of the entire machine and improves the system availability.

[0037] 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

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0039] Figure 1 A schematic diagram of the structure of an energy storage valve submodule provided in one embodiment of the present application;

[0040] Figure 2 Another structural schematic diagram of an energy storage valve submodule provided in an embodiment of the present application;

[0041] Figure 3 Another structural schematic diagram of an energy storage valve submodule provided in an embodiment of the present application;

[0042] Figure 4 Another structural schematic diagram of an energy storage valve submodule provided in an embodiment of the present application;

[0043] Figure 5 Another structural schematic diagram of an energy storage valve submodule provided in an embodiment of the present application;

[0044] Figure 6 A schematic diagram of the structure of a power module in an energy storage valve submodule provided in an embodiment of the present application;

[0045] Figure 7 A schematic diagram of the structure of a power module in an energy storage valve submodule provided in an embodiment of the present application;

[0046] Figure 8 A structural schematic diagram of an MMC type AC direct-mounted energy storage system provided in one embodiment of the present application;

[0047] Fig. 9 A schematic diagram of the structure of a DC direct-mounted energy storage system provided in one embodiment of the present application;

[0048] Fig.10 A schematic diagram of the structure of an AC direct-mounted energy storage system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0049] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field 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" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0051] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0052] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0053] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0054] 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).

[0055] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0056] High-voltage direct-mounted energy storage systems are mainly divided into several technical routes, including MMC (Modular Multilevel Converter) type AC direct-mounted energy storage systems, DC direct-mounted energy storage systems, AC cascade energy storage systems, etc. Compared with traditional energy storage technologies, direct-mounted energy storage systems have higher voltage levels, larger capacities, stronger grid regulation capabilities and grid support functions, and have important research significance for new power systems based on new energy.

[0057] However, the current high-voltage direct-mounted energy storage system still has some problems. For example, when it is necessary to power off during maintenance, due to the characteristics of the high-voltage direct-mounted energy storage system itself, the voltage will accumulate due to the series connection of the energy storage valve submodules. Even if the connection between the main circuit and the high-voltage bus is disconnected, the voltage of each energy storage valve submodule to the ground cannot be directly reduced to the voltage level of a single submodule, and the system still presents high voltage to the ground. In addition, due to the existence of the energy storage module voltage, if the capacitors in the power module and the energy storage module cannot be electrically decoupled, the capacitor voltage cannot be completely discharged and reduced to 0, resulting in leakage current in the system, and the safety of personnel on-board maintenance is very low. In addition, in the case of non-serious faults on the energy storage module side, the fault handling means are only the power module electronic bypass and bypass switch action, and the fault isolation means are limited, and electrical breakpoint isolation cannot be achieved. And in the case of failure of the electronic bypass and bypass switch, the system has to be shut down for maintenance, and the system availability is low.

[0058] According to some embodiments of the present application, referring to Figure 1 , Figure 1 The schematic diagram of the structure of the energy storage valve submodule provided in one embodiment of the present application is shown. For the convenience of explanation, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0059] 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 .

[0060] 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 disconnected from the electrical connection with 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 disconnect the load current between the power module 120 and the energy storage module 110 to form an electrical breakpoint between the two, 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 disconnected from the energy storage module 110 in an electrically isolated manner, so that the housing platform of the energy storage system 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 maintenance personnel; in the case of a type of fault such as relay welding and adhesion in the system that cannot effectively disconnect the electrical connection, this isolation method can be used to achieve safe repair and replacement of relays or other equipment that cannot be disconnected. Similarly, in the case of a non-serious fault on the energy storage module 110 side, the energy storage module 110 is separated from the system composed of the energy storage valve submodule 100, which does not affect the safe operation of the entire machine and 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 action are used in the absence of an isolation switch. If problems such as power switch conduction occur, the nature of the fault is prone to change, resulting in serious faults such as battery direct short circuit. After introducing this isolation method, such problems are effectively avoided, and further development of the fault can be prevented, thereby avoiding serious consequences.

[0061] According to some embodiments of the present application, continue to refer to Figure 1 The switch module 130 includes a first switch group. The first switch group is connected to the positive terminal and the negative terminal of the power module 120 and the positive electrode and the negative electrode of the energy storage module 110. The entire switch module can be the same operating mechanism, that is, integrated into one device, and adopt the same control system, so that the control is more flexible. It is understandable that the form of independently operated switches can also be adopted to achieve electrical isolation.

[0062] According to some embodiments of the present application, referring to Figure 2 , Figure 2 The schematic diagram of the structure of the energy storage valve submodule provided in one embodiment of the present application is shown. For the convenience of explanation, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0063] 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.

[0064] 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, and the circuit design is simplified while the electrical connection between the power module 120 and the energy storage module 110 is released.

[0065] In some embodiments, the first switch S1 and the second switch S2 both include load switches. The load switch may also be referred to as a load isolation switch, which is a type of isolation switch capable of cutting off load current.

[0066] In the technical solution of the embodiment of the present application, the load switch can disconnect the load current while meeting the electrical isolation. 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 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 cannot successfully protect, the energy storage module 110 is protected.

[0067] In some embodiments, the first switch S1 and the second switch S2 both include isolating switches, such as isolators and isolating switches.

[0068] 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 release the electrical connection between the power module 120 and the energy storage module 110; it can also be of a type that cannot disconnect the load current, and 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 release the electrical connection between the power module 120 and the energy storage module 110 to achieve reliable electrical isolation.

[0069] According to some embodiments of the present application, referring to Figure 3 , Figure 3 The schematic diagram of the structure of the energy storage valve submodule provided in one embodiment of the present application is shown. For the convenience of explanation, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0070] 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 .

[0071] 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 the 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.

[0072] According to some embodiments of the present application, referring to Figure 4 , Figure 4 The schematic diagram of the structure of the energy storage valve submodule provided in one embodiment of the present application is shown. For the convenience of explanation, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0073] In some embodiments, the second switch group 140 includes a solid-state circuit breaker S3 , which is connected in series with the first switch S1 or the second switch S2 .

[0074] Solid-state circuit breaker S3 is a type of fast-acting protection device. By using power electronics, it can suppress the rise of short-circuit current within a few microseconds and transfer the short-circuit current out of the circuit, which is equivalent to reducing the circuit current to near 0. The response speed and protection capability of solid-state circuit breaker S3 are far better than the fuses generally configured in the energy storage system. It is understandable that if solid-state circuit breaker S3 is used to protect the circuit, it will no longer be necessary to configure any fuses in the energy storage system, greatly reducing the cumbersomeness of fuse configuration. At the same time, it avoids the cumbersome process of replacing the fuse after the system short-circuit blows. Even if the energy storage system is still configured with a fuse, it is only used as a backup and redundant protection method for the solid-state circuit breaker S3, and no longer relies on the fuse as the main protection method.

[0075] 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.

[0076] According to some embodiments of the present application, referring to Figure 5 , Figure 5 The schematic diagram of the structure of the energy storage valve submodule provided in one embodiment of the present application is shown. For the convenience of explanation, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0077] In some embodiments, the second switch group 140 includes: two circuit breakers or two relays, see Figure 5 S4 and S5 are shown. The second switch group 140 includes two circuit breakers, which are respectively connected in series with the first switch S1 and the second switch S2; the second switch group 140 includes two relays, which are respectively connected in series with the first switch S1 and the second switch S2.

[0078] Use isolating switches and devices that can disconnect load current. Circuit breakers, contactors and other devices can cut off load current in the circuit, but they cannot serve as reliable electrical isolation means. Therefore, isolating switches are used in conjunction with circuit breakers, contactors and other devices. A set of devices is used to disconnect load current, and then the isolating switches are used as reliable electrical isolation means.

[0079] 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.

[0080] According to some embodiments of the present application, continue to refer to Figure 2 In some embodiments, the second switch group 140 includes a power module 120 .

[0081] 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.

[0082] In some embodiments, the power module 120 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 110 through the switch module 130 .

[0083] There may be a plurality of first switch elements, and the plurality of first switch elements are connected in series and / or in parallel, and the energy storage element is connected in parallel with the plurality of first switch elements connected in series and / or in parallel. In a specific implementation, the plurality of first switch elements connected in series and / or in parallel include a full-bridge circuit or a half-bridge circuit. When the power module 120 is connected to the energy storage module 110, the energy storage element may be charged first, thereby reducing the impact of the large current on the first switch element and improving the reliability of the energy storage valve submodule 100.

[0084] In the technical solution of the embodiment of the present application, the power module 120 includes a half-bridge circuit or a full-bridge circuit. It should be noted that the half-bridge circuit is a power circuit including two switch tubes, and the full-bridge circuit is a power circuit including four switch tubes. The half-bridge circuit has low cost and simple circuit; the full-bridge circuit has high cost and relatively complex circuit. However, the full-bridge circuit has less interference than the half-bridge circuit and has higher reliability. Flexible configuration of the power module 120 is achieved, and the flexibility of the design of the energy storage valve submodule 100 is improved.

[0085] According to some embodiments of the present application, referring to Figure 6 , Figure 6The schematic diagram of the structure of the power module in the energy storage valve submodule provided in one embodiment of the present application is shown. For the sake of convenience, only the part related to the present embodiment is shown, which is described in detail as follows:

[0086] 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;

[0087] The input end of the first switch tube T1, the cathode of the first diode D1, the input end of the third switch tube T3, the cathode of the third diode D3 and the first end of the first capacitor C1 collectively serve as the first positive terminal of the full-bridge circuit; the output end of the second switch tube T2, the cathode of the second diode D2, the output end of the fourth switch tube T4, the cathode of the fourth diode D4 and the second end of the first capacitor C1 collectively serve as the first negative terminal of the full-bridge circuit; the output end of the third switch tube T3, the cathode of the third diode D3, the input end of the fourth switch tube T4 and the cathode of the fourth diode D4 collectively serve as the second positive terminal of the full-bridge circuit; the output end of the first switch tube T1, the cathode of the first diode D1, the input end of the second switch tube T2 and the cathode of the second diode D2 collectively serve as the second negative terminal of the full-bridge circuit;

[0088] 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; the second negative terminal of the full-bridge circuit is the second negative terminal of the power module 120.

[0089] It should be noted that the above-mentioned switch tubes include triodes, field effect tubes and insulated gate bipolar transistors.

[0090] The full-bridge circuit works in the first switching state as follows: the positive electrode of the third diode D3 is connected to the first direct current output by the grid, the negative electrode of the third diode D3 outputs the first direct current to the energy storage module 110, the positive electrode of the second diode D2 is connected to the first direct current charged by the energy storage module 110, and the negative electrode of the second diode D2 outputs the first direct current charged by the energy storage module 110 to the grid.

[0091] The full-bridge circuit works in the second switching state as follows: the input end of the third switch tube T3 is connected to the second direct current output from the positive electrode of the energy storage module 110, the output end of the third switch tube T3 outputs the second direct current to the grid, the input end of the second switch tube T2 is connected to the second direct current fed back from the grid, and the output end of the second switch tube T2 outputs the fed back second direct current to the negative electrode of the energy storage module 110.

[0092] The full-bridge circuit works 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 power 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.

[0093] The full-bridge circuit works 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.

[0094] The above full-bridge circuit can self-eliminate DC faults and can be applied in scenarios with high input voltage.

[0095] According to some embodiments of the present application, referring to Figure 7 , Figure 7 A schematic diagram of the structure of the power module in the energy storage valve submodule provided in an embodiment of the present application is shown. For the convenience 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.

[0096] 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 together 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 together serve as the first negative terminal of the half-bridge circuit 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 together serve as the second positive terminal of the half-bridge circuit.

[0097] 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; the second negative terminal of the half-bridge circuit is the second negative terminal of the power module 120.

[0098] It should be noted that the above-mentioned switch tubes include triodes, field effect tubes and insulated gate bipolar transistors.

[0099] The above-mentioned half-bridge circuit works in the first transfer state specifically as follows: the positive electrode of the fifth diode D5 is connected to the first direct current output by the power grid, the negative electrode of the fifth diode D5 outputs the first direct current to the positive electrode of the energy storage module 110, and the negative electrode of the energy storage module 110 outputs the first direct current charged by the energy storage module 110 to the power grid.

[0100] The above-mentioned half-bridge circuit works in the second transfer state specifically as follows: the input end of the fifth switch tube T5 is connected to the second direct current output by the positive electrode of the energy storage module 110, the output end of the fifth switch tube T5 outputs the second direct current to the grid, and the grid feeds back the second direct current to the negative electrode of the energy storage module 110.

[0101] The above half-bridge circuit works in the first cut-off state specifically as follows: the input end of the sixth switch tube T6 is connected to the first direct current output by the power grid, and the output end of the sixth switch tube T6 outputs the first direct current.

[0102] Specifically, the half-bridge circuit works 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.

[0103] The above half-bridge circuit has a simple structure and low cost.

[0104] 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 turn on and off, and the control signal is used to control the switch module 130 to turn on and off.

[0105] The controller can also output a driving signal with a preset duty cycle to modulate the power module 120, so that the current between the power module 120 and the energy storage module 110 changes, such as approaching 0 to disconnect the load current, or the duty cycle is 100% to fully conduct. The controller outputs multiple control signals, which are generally high and low levels, to drive each switch in the switch module 130 to turn on and off.

[0106] Optionally, the controller includes a submodule controller (SubModuleController, SMC), which is used to monitor the working state of the energy storage valve submodule 100, receive control information issued by the valve base controller (VBC) of the energy storage valve, and transmit the state of the energy storage valve submodule 100 to the VBC. At the same time, when the SMC detects that the energy storage valve submodule 100 fails, the SMC controls the power module 120 and the switch module 130 to be turned off so that the energy storage module 110 is bypassed, and transmits the fault information to the VBC, which can ensure that other submodules continue to operate normally.

[0107] 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.

[0108] 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.

[0109] Since 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, so that the power module 120 is electrically decoupled from the energy storage module 110. When repairing components other than the energy storage module 110 in the energy storage valve, there will be no leakage current, thereby ensuring the personal safety of the repair personnel. Similarly, if a non-serious fault occurs on the energy storage module 110 side of the energy storage valve, the switch module 130 is used to separate the energy storage module 110 from the system under the premise that the energy storage valve is locked, which does not affect the safe operation of the entire machine and improves the system availability.

[0110] 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.

[0111] 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.

[0112] Since 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 to ensure the personal safety of maintenance personnel. Similarly, if a non-serious fault occurs on the energy storage module 110 side of the energy storage station, the switch module 130 is used to separate the energy storage module 110 from the system under the premise of locking the energy storage station, which does not affect the safe operation of the entire machine and improves the system availability.

[0113] Figure 8 The structure diagram of an MMC type AC direct-mounted energy storage system that can be applied to an energy storage station according to an embodiment of the present application is shown. Figure 8As shown, the MMC type AC direct-mounted energy storage system includes 6 converter bridge arm groups, and the 6 converter bridge arm groups (i.e., energy storage valves) 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. Among them, the first converter bridge arm group 810 and the second converter bridge arm group 820 are connected in series, the third converter bridge arm group 880 and the fourth converter bridge arm group 840 are connected in series, the fifth converter bridge arm group 850 and the sixth converter bridge arm group 860 are connected in series, and the connection point between the first converter bridge arm group 810 and the second converter bridge arm group 820, the connection point between the third converter bridge arm group 880 and the fourth converter bridge arm group 840, and the connection point between the fifth converter bridge arm group 850 and the sixth converter bridge arm group 860 are respectively connected to the three-phase AC power grid. Each converter bridge arm group is composed of N energy storage valve submodules 801 and other auxiliary devices connected in series, where N is a positive integer. Figure 8 As shown, the N energy storage valve submodules 801 include energy storage valve submodules 801_1, 801_2, ..., 801_N. The auxiliary device 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 device may be Figure 8 The reactors L1~L6.

[0114] Fig. 9 The structure diagram of a DC direct-mounted energy storage system according to an embodiment of the present application is shown. Fig. 9 As shown in FIG. 1 , the DC direct-mounted energy storage system is also called an energy storage valve, which is composed of n energy storage valve submodules SM and other auxiliary equipment connected in series, where n is a positive integer. Fig. 9 As shown, the n energy storage valve submodules SM include energy storage submodules SM#1, ..., SM#n-1, SM#n. The auxiliary device 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 device may include Fig. 9 The fast switch S11 between the positive pole and the positive DC bus of the n energy storage valve submodules SM, the isolating knife S12, the grounding knife S13 connected to both ends of the fast switch S11 and the isolating knife S12, the current transformer CT1 and the current limiting reactor L7, the isolating knife S14 between the negative pole and the positive DC bus of the n energy storage valve submodules SM, the grounding knife S15 connected to both ends of the isolating knife S14 and the current transformer CT2. In addition, a voltage transformer VT1 is also provided on the positive DC bus.

[0115] Fig.10 The structure 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 is shown. Fig.10As shown, 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 the three-phase AC power grid. Each energy storage valve is composed of N energy storage valve submodules 1101 and other auxiliary equipment connected in series, where N is a positive integer. Fig.10 As shown, the N energy storage valve submodules 1101 include energy storage valve submodules 1101_1, 1101_2, ..., 1101_N. The auxiliary device 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 device may be Fig.10 The reactor.

[0116] 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 replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: The first switch and the second switch include load switches.

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

6. The energy storage valve submodule according to claim 5, characterized in that: 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, characterized in that: 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, characterized in that: The second switch group includes: Two circuit breakers, the two circuit breakers are respectively connected in series with the first switch and the second switch; or Two relays are respectively connected in series with the first switch and the second switch.

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

10. The energy storage valve submodule according to claim 1, characterized in that: 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.

11. The energy storage valve submodule according to claim 1, characterized in that: The power module includes a half-bridge circuit or a full-bridge circuit.

12. The energy storage valve submodule according to any one of claims 1 to 11, characterized in that: 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.

13. An energy storage valve, characterized in that: The energy storage valve comprises an energy storage valve submodule as described in any one of claims 1 to 12.

14. An energy storage station, characterized in that: The energy storage station comprises the energy storage valve submodule according to any one of claims 1 to 12.

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