High-voltage direct-hanging type network-constructing energy storage system and topological structure

Abstract

The invention relates to the technical field of energy storage, in particular to a high-voltage direct-hanging type net-forming type energy storage system and a topological structure, and a PCS converter in the energy storage system comprises a plurality of sub-modules, each sub-module comprises an H-bridge circuit, and each H-bridge circuit is composed of four insulated gate bipolar transistors; at least one DC support capacitor and inductor connected to the DC side of the H-bridge circuit and used for smoothing DC voltage fluctuation; the bypass switch is connected to two ends of the H-bridge circuit in parallel and is used for isolating the sub-module when the sub-module fails; and the direct-current interface circuit is connected in parallel to two ends of the plurality of sub-modules and is used for adjusting input and output of voltage according to instructions issued by the control system. Therefore, the problems that in the prior art, basic over-current protection is relied on, the reliability is poor in the face of complex faults, the structure occupies a large space, and maintenance is inconvenient are solved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a high-voltage direct-hanging grid-type energy storage system and topological structure. Background Art

[0002] As the global demand for clean energy grows, energy storage technology has received widespread attention as a key means to balance electricity supply and demand, improve grid stability, and promote access to renewable energy. As an efficient and reliable solution, high-voltage direct-mounted grid-connected energy storage systems have shown great potential in large-scale energy storage applications. As the core component of the system, the PCS converter (Power Conversion System Converter) is responsible for achieving bidirectional conversion between DC and AC, and ensuring that the output voltage and frequency meet load requirements and grid standards, thereby ensuring power quality.

[0003] In related technologies, PCS converters rely only on basic overcurrent protection and lack multi-level and multi-dimensional protection strategies. They may perform poorly in the face of complex faults and have poor reliability. They do not fully consider possible problems under long-term operation, such as corona discharge leading to aging of insulation materials. They do not properly handle the coupling interference between the primary circuit and the secondary control system, which can easily cause control signal distortion or malfunction. Some products have not undergone rigorous EMC testing, resulting in unexpected situations during field use. They fail to fully utilize the compact advantages brought by modular design, and the equipment is bulky, which is not conducive to deployment and transportation. Due to the limitations of existing technologies, fluctuations may occur in the power conversion process, which in turn affects the stability of the power grid. Summary of the invention

[0004] The present application provides a high-voltage direct-mounted grid-type energy storage system and topology structure to solve the problems in the related technology of relying on basic overcurrent protection, poor reliability in the face of complex faults, and inconvenient maintenance due to large structure space occupation.

[0005] In a first aspect, an embodiment of the present application provides a PCS converter, comprising: a plurality of sub-modules, each sub-module comprising an H-bridge circuit, wherein the H-bridge circuit is composed of four insulated gate bipolar transistors; at least one DC support capacitor and inductor connected to the DC side of the H-bridge circuit, for smoothing DC voltage fluctuations; a bypass switch connected in parallel at both ends of the H-bridge circuit, for isolating the sub-module when it fails; and a DC interface circuit connected in parallel at both ends of the plurality of sub-modules, for adjusting the input and output of the voltage according to instructions issued by a control system.

[0006] Optionally, the submodule includes: a first insulated gate bipolar transistor to a fourth insulated gate bipolar transistor and a diode; wherein, the first insulated gate bipolar transistor and the second insulated gate bipolar transistor are connected in series to form a first bridge arm, the third insulated gate bipolar transistor and the fourth insulated gate bipolar transistor are connected in series to form a second bridge arm, the first bridge arm and the second bridge arm constitute an H-bridge circuit, and the first insulated gate bipolar transistor to the fourth insulated gate bipolar transistor are anti-parallel connected by a diode.

[0007] Optionally, the DC interface circuit includes: a battery pack, a first switch, a second switch, a resistor and a fuse, wherein the battery pack is composed of a plurality of battery cells connected in series, the positive pole of the battery pack is connected to the second switch and the second switch, the negative pole of the battery pack is connected to the fuse, the other end of the fuse is connected to the resistor, and the other end of the resistor is connected to the first switch or the second switch depending on the switch.

[0008] Optionally, it also includes: a conductive busbar, which is used to efficiently distribute DC power to each sub-module and aggregate the AC output of each sub-module; an optical cable assembly, which is used to transmit control signals and monitoring data, realize communication between the control system and the sub-modules, and provide electrical isolation; and a supporting insulator, which is used to mechanically support and electrically isolate the internal components of the converter.

[0009] Optionally, the bypass switch is a relay, the conductive busbar is made of a metal material with low resistivity and good conductivity, and the supporting insulator is made of a high-strength ceramic material.

[0010] The second aspect of the present application provides a high-voltage direct-mounted grid-connected energy storage system, comprising: a PCS converter as described in the above embodiment, used for bidirectional conversion between direct current and alternating current; a control system, used to generate corresponding control instructions according to grid demand to control the PCS converter to perform target operations.

[0011] Optionally, the control system includes: a battery management system, a submodule control unit, a valve control module and a power control panel; wherein the battery management system is connected to the battery pack of the PCS converter, and is used to output a corresponding voltage value to match the grid demand, or to store the direct current converted by the PCS converter; the submodule control unit is connected to multiple submodules of the PCS converter, and is used to control multiple submodules of the PCS converter; the valve control module is communicatively connected to the submodule control unit, and is used to send valve control instructions to the submodule control unit according to grid demand to control the valve status of each submodule; a power control panel is used to control the regulation of the charging and discharging power of the high-voltage direct-mounted grid-type energy storage system.

[0012] Optionally, it also includes: a switch for network communication between modules of the high-voltage direct-mounted grid-forming energy storage system; and a monitoring system for real-time monitoring of the operating status of modules of the high-voltage direct-mounted grid-forming energy storage system.

[0013] Optionally, it also includes: an inspection platform for maintaining and inspecting the internal structure of the converter, wherein the inspection platform is equipped with safety guardrails and anti-slip floors.

[0014] The third aspect of the present application provides a topological structure of a high-voltage direct-mounted grid-type energy storage system, comprising: a container; a plurality of load-bearing frames arranged inside the container, an energy storage valve group being arranged on the load-bearing frames, and an insulating base being arranged between the energy storage valve group and the container; guide rails arranged in parallel are installed on the energy storage valve group bracket, a tray structure is arranged on the guide rail, and a PCS converter and a control system are placed inside the tray structure; wherein, a sub-module removable design based on a slide rail controls the pushing and pulling of a sub-module board, a sub-module body, and a control system to realize independent partitioning arrangement of each sub-module of the converter, wherein a primary and secondary partition shielding design is adopted inside each sub-module, and a primary power circuit and a secondary control system are placed in independent cavities respectively to reduce electromagnetic interference; a roof-mounted air conditioner is arranged on the top of the container, and a fire auxiliary control system is arranged on both sides.

[0015] Therefore, this application has at least the following beneficial effects:

[0016] (1) The embodiments of the present application are based on the optimized coordination of high current density insulated gate bipolar transistors and autonomous digital drive, thereby achieving micro-process optimization of turning on and off the insulated gate bipolar transistors, reducing overvoltage stress, optimizing the operating area of ​​the insulated gate bipolar transistors, ensuring current and voltage margins, and taking into account both steady-state and transient characteristics, thereby improving the reliability of the converter.

[0017] (2) The embodiment of the present application not only ensures the rapidity of protection but also provides excellent fault handling capabilities by jointly implementing a multi-level overcurrent protection mechanism.

[0018] (3) In the embodiment of the present application, the submodule structure adopts an explosion-proof design, so that the failed device can be well isolated from other components, and the reliable operation of adjacent components or the entire converter will not be affected when it fails; the installation position of the submodule board takes into account the convenience of debugging and maintenance, and can be easily detached from the submodule body; a high-speed vacuum bypass switch is used to avoid equipment tripping caused by submodule failure, which is convenient for operation and maintenance; the submodule is removable based on a slide rail, which is convenient for installation, inspection and maintenance; parallel guide rails are installed on the converter tower bracket, and when the submodule is pushed in and pulled out as a whole, there is rolling friction between the chassis and the guide rails, which is easy to operate.

[0019] (4) The embodiments of the present application are to distinguish interference circuits from sensitive circuits and arrange them in zones; focus on shielding sensitive circuits to reduce mutual electromagnetic coupling and improve anti-interference performance; use coaxial cables for drive lines and optimize drive routing paths, while taking into account the shutdown characteristics and consistency of the upper and lower tubes.

[0020] (5) The embodiment of the present application reduces the floor space through modular and supported valve stack design, facilitates installation and maintenance, and improves the integration and flexibility of the system.

[0021] (6) The software in the embodiment of the present application is structured in design and visually developed, and has complete self-monitoring and alarm functions, which makes it easy for operation and maintenance personnel to find and deal with problems; the dual configuration and online maintenance are combined to improve the reliability of the valve control system.

[0022] (7) The embodiments of the present application cover the entire range of components, submodules, valve sections, and converters, including basic device testing, converter module testing, high voltage and high current operation testing, control and protection system testing, and closed-loop verification of the entire system, providing a verification method for system research, equipment development, and engineering implementation; it not only improves the overall performance of the system, but also provides a solid technical guarantee for future engineering implementation.

[0023] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0025] Figure 1 A schematic diagram of a PCS converter provided according to an embodiment of the present application;

[0026] Figure 2 A block diagram of a high-voltage direct-mounted grid-type energy storage system provided according to an embodiment of the present application;

[0027] Figure 3 A schematic diagram of a high-voltage direct-mounted grid-type energy storage system provided according to an embodiment of the present application;

[0028] Figure 4 A schematic diagram of the topological structure of a high-voltage direct-mounted grid-type energy storage system provided according to an embodiment of the present application;

[0029] Figure 5 A front view of the containerized energy storage converter arrangement provided according to an embodiment of the present application;

[0030] Figure 6A top view of the containerized energy storage inverter arrangement provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0032] The following describes the high-voltage direct-mounted grid-type energy storage system and topological structure of an embodiment of the present application with reference to the accompanying drawings.

[0033] Specifically, Figure 1 A schematic diagram of a PCS converter provided in an embodiment of the present application.

[0034] like Figure 1 As shown, the PCS converter includes: a plurality of submodules SM, a DC support capacitor C, an inductor L, a bypass switch KM and a DC interface circuit.

[0035] Each submodule SM includes an H-bridge circuit, which is composed of four insulated gate bipolar transistors; at least one DC support capacitor C and inductor L connected to the DC side of the H-bridge circuit are used to smooth DC voltage fluctuations; a bypass switch KM connected in parallel at both ends of the H-bridge circuit is used to isolate the submodule when it fails; and a DC interface circuit connected in parallel at both ends of multiple submodules SM is used to adjust the voltage input and output according to instructions issued by the control system.

[0036] Among them, the bypass switch KM is a relay.

[0037] It can be understood that the sub-module in the embodiment of the present application realizes efficient, stable and easy-to-maintain power conversion function by integrating an efficient H-bridge circuit, a stable DC support element and a safe and reliable bypass mechanism, which can ensure the long-term stable operation of the system.

[0038] In the embodiment of the present application, the submodule SM includes: a first insulated gate bipolar transistor G1, a second insulated gate bipolar transistor G2, a third insulated gate bipolar transistor G3, a fourth insulated gate bipolar transistor G4 and a diode D.

[0039] Among them, the first insulated gate bipolar transistor G1 and the second insulated gate bipolar transistor G2 are connected in series to form a first bridge arm, the third insulated gate bipolar transistor G3 and the fourth insulated gate bipolar transistor G4 are connected in series to form a second bridge arm, the first bridge arm and the second bridge arm constitute an H-bridge circuit, and the first insulated gate bipolar transistor G1 to the fourth insulated gate bipolar transistor G4 are anti-parallel connected by a diode D.

[0040] It can be understood that the embodiment of the present application can realize bidirectional power conversion from DC to AC (inversion) and AC to DC (rectification) through the switching action of the IGBT in the H-bridge circuit, and adjust the working state of the H-bridge circuit as needed, so as to accurately control the amplitude and frequency of the output voltage to ensure that the power quality meets the load requirements and grid standards; each IGBT is anti-parallel with a diode D, which provides a current follow-up path when the IGBT is turned off, avoids overvoltage stress, and enhances the reliability of the system; when an IGBT fails, the anti-parallel diode can continue to carry current to prevent other components from being damaged; in addition, the bypass switch KM can isolate the entire submodule in the event of a fault without affecting the normal operation of other parts of the system; IGBT has a low on-state voltage drop, reduces power loss, improves overall conversion efficiency, has a fast switching speed, can respond quickly to control signals, reduces switching losses, and further improves efficiency.

[0041] It should be noted that the DC support capacitor (C) and inductor (L) are used to smooth DC voltage fluctuations, provide a stable DC power supply, absorb instantaneous power fluctuations, play an energy buffering role, and reduce the impact on energy storage equipment or power grids; the fast switching characteristics of IGBT and the design of anti-parallel diodes help reduce the electromagnetic interference generated during the switching process and improve the electromagnetic compatibility of the system; by rationally laying out the drive lines and optimizing the routing paths, electromagnetic coupling can be further reduced and anti-interference performance can be improved.

[0042] In the embodiment of the present application, the DC interface circuit includes: a battery pack E, a first switch DS 1 , the second switch DS 2 , resistor R and fuse F U .

[0043] The battery pack E is composed of a plurality of battery cells connected in series, and the positive electrode of the battery pack E is connected to the second switch DS. 1 and the second switch DS 2 , the negative pole of battery pack E is connected to fuse F U , Fuse F U The other end of the resistor R is connected to the first switch DS according to the switch. 1 Or the second switch DS 2 .

[0044] It can be understood that the DC interface circuit design of the embodiment of the present application not only achieves high safety and flexible energy management by introducing key components such as fuse FU, dual switch control, resistor R, but also provides many advantages such as overload protection, easy expansion and maintenance, high-efficiency conversion and precise control.

[0045] It should be noted that the fuse FU can quickly blow when the current exceeds the set threshold, cutting off the current path and preventing short circuit or other faults from causing serious damage to the system; by controlling the states of the first switch DS1 and the second switch DS2, the direction of energy flow between the battery pack E and the external circuit can be flexibly adjusted; for example: when DS1 is closed and DS2 is disconnected, the battery pack E can supply power to the load through DS1; when DS2 is closed and DS1 is disconnected, the battery pack E can be charged from the power grid through DS2. The bidirectional control enables the system to dynamically adjust the working mode according to actual needs and improve energy utilization efficiency.

[0046] When an abnormal situation (such as a short circuit) occurs, the resistor R can limit the sharp rise in current, providing more time for the fuse FU to respond; the resistor R can also be used to detect the current, helping the control system identify potential problems and take appropriate measures. Due to the use of modular components (such as battery packs, switches, resistors, and fuses), the entire DC interface circuit is easy to expand and maintain. If a component has a problem, it can be quickly replaced without affecting the functions of other parts. Reasonable selection of the resistance value of the resistor R and the rated current of the fuse FU can minimize energy loss and improve the overall efficiency of the system while ensuring safety.

[0047] In the embodiment of the present application, it also includes: a conductive busbar, an optical cable assembly and a supporting insulator.

[0048] Among them, the conductive busbar is used to efficiently distribute DC power to each sub-module and aggregate the AC output of each sub-module; the optical cable assembly is used to transmit control signals and monitoring data, realize communication between the control system and the sub-modules, and provide electrical isolation; the supporting insulator is used to mechanically support and electrically isolate the internal components of the converter.

[0049] Among them, the conductive busbar is made of metal material with low resistivity and good conductivity, and the supporting insulator is made of high-strength ceramic material.

[0050] It can be understood that the embodiments of the present application can not only improve the performance and reliability of the system through carefully designed conductive busbars, optical cable assemblies and supporting insulators, but also provide solid technical support for future engineering implementation.

[0051] It should be noted that the conductive busbar is used to efficiently distribute DC power to each submodule and aggregate the AC output of each submodule. By using metal materials with low resistivity and good conductivity (such as copper or aluminum), the energy loss during transmission can be significantly reduced and the overall efficiency can be improved; low-resistivity conductive materials can reduce the heat generated when current flows, thereby reducing temperature rise and extending the service life of the equipment, while reducing dependence on additional cooling systems; the conductive busbar can integrate multiple connection points, simplifying complex cable wiring, improving the convenience of installation and maintenance, and also reducing problems caused by wiring errors.

[0052] Optical cable assemblies are used to transmit control signals and monitoring data to achieve communication between the control system and submodules. Optical fiber communication has the characteristics of high bandwidth and low latency, and can support real-time monitoring and rapid response to ensure the stable operation of the system. Compared with traditional wires, optical cables are not affected by electromagnetic interference and are particularly suitable for use in power electronic equipment, avoiding noise problems in signal transmission and improving communication reliability. Optical cables provide natural electrical isolation characteristics, effectively preventing the risk of short circuits between different potentials and enhancing the safety and stability of the system.

[0053] The supporting insulators are made of high-strength ceramic material, which provides solid mechanical support and ensures the stable installation of the internal components of the converter, especially in vibration and impact environments, thus ensuring the long-term reliability of the equipment. The ceramic material has excellent insulation properties and can provide reliable electrical isolation under high voltage conditions, preventing current leakage and other safety hazards, thus improving the overall safety of the system. The ceramic material also has good corrosion resistance and high temperature resistance, making it suitable for various harsh working environments, further extending the service life of the equipment.

[0054] Specifically, the PCS power module is the smallest unit of testing and design, which consists of IGBT, DC capacitor, bypass switch and control circuit, etc. The power unit is mainly composed of H-bridge power unit composed of high-speed fully controlled power electronic power devices, which can output AC voltage with adjustable amplitude and frequency. A power unit includes 4 high-speed power electronic switching devices IGBT (1700V voltage level IGBT is used in this project), two switching devices are connected in series to form a bridge arm, and the middle connection end of the two bridge arms is led out as the AC output end of the power unit. The power unit also includes DC support capacitors, AC bypass switches and necessary unit control protection systems, etc. The DC support capacitors use thin film capacitors and are connected between the DC positive and negative busbars of the power unit.

[0055] According to the PCS converter proposed in the embodiment of the present application, the sub-module realizes an efficient, stable and easy-to-maintain power conversion function by integrating an efficient H-bridge circuit, a stable DC support element and a safe and reliable bypass mechanism, which can ensure the long-term stable operation of the system. Through the switching action of the IGBT in the H-bridge circuit, bidirectional power conversion from DC to AC (inversion) and AC to DC (rectification) can be achieved. The working state of the H-bridge circuit is adjusted as needed to accurately control the amplitude and frequency of the output voltage to ensure that the power quality meets the load requirements and grid standards.

[0056] Next, the high-voltage direct-hanging grid-type energy storage system proposed according to the embodiment of the present application is described with reference to the accompanying drawings.

[0057] Figure 2 It is a block diagram of a high-voltage direct-mounted grid-type energy storage system according to an embodiment of the present application.

[0058] like Figure 2 As shown, the high-voltage direct-mounted grid-connected energy storage system 20 includes: a PCS converter 10 and a control system 30 .

[0059] The PCS converter 10 is used for bidirectional conversion between direct current and alternating current; the control system 30 is used to generate corresponding control instructions according to grid demand to control the PCS converter to perform target operations.

[0060] It can be understood that the embodiment of the present application can generate corresponding control instructions according to the needs of the power grid to control the PCS converter to perform the target operation, and realize the micro-process optimization of IGBT opening and closing based on the optimized coordination of high current density IGBT and autonomous digital drive, reduce overvoltage stress, optimize the IGBT operating working area, ensure current and voltage margin, take into account the steady-state and transient characteristics, and improve the reliability of the converter; through the combination of digital drive, valve control, and control protection, multi-level overcurrent protection is realized, and through the coordination of protection parameters such as setting value and delay, while ensuring the rapidity of protection, excellent fault handling capability is provided.

[0061] In the embodiment of the present application, the control system 30 includes: a battery management system, a submodule control unit, a valve control module and a power control panel.

[0062] Among them, the battery management system is connected to the battery pack of the PCS converter, and is used to output the corresponding voltage value to match the grid demand, or to store the DC power converted by the PCS converter; the submodule control unit is connected to multiple submodules of the PCS converter, and is used to control multiple submodules of the PCS converter; the valve control module is communicated with the submodule control unit, and is used to send valve control instructions to the submodule control unit according to the grid demand to control the valve status of each submodule; the power control panel is used to control the regulation of the charging and discharging power of the high-voltage direct-mounted grid-type energy storage system.

[0063] It can be understood that the control system of the embodiment of the present application not only achieves efficient power conversion and management through carefully designed components, but also significantly improves the reliability and safety of the system, ensuring the long-term stable operation of the system.

[0064] In the embodiment of the present application, it also includes: a switch for network communication between the modules of the high-voltage direct-mounted grid-type energy storage system; and a monitoring system for real-time monitoring of the operating status of the modules of the high-voltage direct-mounted grid-type energy storage system.

[0065] It can be understood that the introduction of the switch and monitoring system of the embodiment of the present application not only improves the communication efficiency and monitoring capabilities of the high-voltage direct-mounted grid-type energy storage system, but also significantly enhances the reliability and safety of the system, simplifies the operation and maintenance work, and provides a solid technical guarantee for the efficient and safe operation of the system.

[0066] In the embodiment of the present application, it also includes: a maintenance platform for maintaining and inspecting the internal structure of the inverter, wherein the maintenance platform is equipped with safety guardrails and anti-slip floors.

[0067] It can be understood that the maintenance platform equipped with safety guardrails and anti-slip floors in the embodiment of the present application not only improves the maintenance safety and efficiency of the high-voltage direct-hanging grid-type energy storage system, but also significantly enhances the reliability and compliance of the system.

[0068] Specifically, if Figure 3 As shown in the figure, all the type test items of voltage source converters cover the entire range of components, submodules, valve sections, and converters. Including testing of basic devices such as IGBT and high-speed switches, converter module testing, converter high voltage and high current operation testing, control and protection system testing, and closed-loop verification of the entire system, providing verification means for system research, equipment development, and engineering implementation; building a high junction temperature and non-delay short-circuit test platform with a short-circuit current peak of 60kA and an adjustable waveform to meet the converter short-circuit test requirements; building a flexible AC equipment whole machine access test platform with a voltage of 35kV to fully examine the overall operating performance of the converter, valve control, and control protection. With the help of multi-level test methods, the converter is tested and verified in strict accordance with the test requirements of this project, and the converter equipment is ensured to meet the engineering requirements through test optimization and iteration.

[0069] According to the high-voltage direct-mounted grid-connected energy storage system proposed in the embodiment of the present application, corresponding control instructions are generated according to the grid demand to control the PCS converter to perform the target operation, and the micro-process optimization of IGBT opening and closing is realized based on the optimized coordination of high current density IGBT and autonomous digital drive, the overvoltage stress is reduced, the IGBT operating working area is optimized, the current and voltage margins are ensured, the steady-state and transient characteristics are taken into account, and the reliability of the converter is improved; multi-level overcurrent protection is realized through the combination of digital drive, valve control, and control protection, and through the coordination of protection parameters such as protection setting and delay, while ensuring the rapidity of protection, excellent fault handling capability is provided.

[0070] Next, the topological structure of the high-voltage direct-mounted grid-type energy storage system proposed in accordance with an embodiment of the present application will be described with reference to the accompanying drawings.

[0071] Figure 4 It is a schematic diagram of the topological structure of the high-voltage direct-mounted grid-type energy storage system of an embodiment of the present application.

[0072] like Figure 4 As shown, the topological structure of the high-voltage direct-mounted grid-type energy storage system includes the following structures: a container; a plurality of load-bearing frames are arranged inside the container, a storage valve group is arranged on the load-bearing frame, and an insulating base is arranged between the storage valve group and the container; parallel guide rails are installed on the energy storage valve group bracket, a tray structure is arranged on the guide rail, and a PCS converter and a control system are placed inside the tray structure; wherein, the sub-module removable design based on the slide rail controls the push-in and pull-out of the sub-module board and the sub-module body and the control system to realize the independent partition arrangement of each sub-module of the converter, wherein each sub-module adopts a primary and secondary partition shielding design, and the primary power circuit and the secondary control system are placed in independent cavities respectively to reduce electromagnetic interference; a roof-mounted air conditioner is arranged on the top of the container, and a fire auxiliary control system is arranged on both sides.

[0073] It can be understood that the embodiment of the present application can adopt a primary and secondary partition shielding design inside the sub-module, and place the primary power circuit and the secondary control system in independent cavities respectively, which can ensure that the secondary control system is effectively electromagnetically shielded and suppress the coupling interference between the primary and secondary circuits; the partition shielding method can effectively isolate the main power device when it fails, avoiding physical damage to the secondary circuit, so that the faulty sub-module can be bypassed normally to ensure the normal operation of the whole machine; the tray-type structure design is adopted, which greatly improves the scalability and versatility of the sub-module and effectively reduces the product development cost; the structural strength of the valve group is improved, the difficulty of installing the sub-module into the valve frame is reduced, and the feasibility of the project implementation is improved; the horizontal structure scheme is adopted, which greatly reduces the overall spatial size of the valve group and is conducive to the electrical connection between the sub-modules.

[0074] It should be noted that this application proposes and practices a converter submodule design method with partition layout and shielding design:

[0075] (1) Distinguish interference circuits and sensitive circuits and arrange them in zones;

[0076] (2) Focus on shielding sensitive circuits to reduce mutual electromagnetic coupling and improve anti-interference performance;

[0077] (3) The drive line uses coaxial cable to optimize the drive line path, while taking into account the shutdown characteristics and the consistency of the upper and lower tubes;

[0078] Relying on the CNAS laboratory, a comprehensive submodule electromagnetic compatibility test was carried out, in which the radio frequency electromagnetic field radiation immunity in the three directions of XYZ was not less than 50V / m;

[0079] Through electromagnetic compatibility testing, sensitive ports, secondary lines, and electronic circuits were further identified, and suppression units were installed in a targeted manner. The reliability of the design was confirmed through multiple flexible AC and DC projects.

[0080] Specifically, the power module structure adopts an explosion-proof design as a whole. When a power device fails inside the module, it will not affect the adjacent valve units. The submodule adopts a primary and secondary partition shielding design, placing the primary power circuit and the secondary control system in independent cavities, which can ensure that the secondary control system is effectively electromagnetically shielded and suppress the coupling interference between the primary and secondary circuits. The partition shielding method can effectively isolate the main power device when it fails, avoiding physical damage to the secondary circuit, so that the faulty submodule can be bypassed normally to ensure the normal operation of the whole machine. At the same time, the partition design can realize the overall disassembly and assembly of the secondary control system, greatly simplifying the production process and improving the maintainability of the equipment.

[0081] Based on the partition shielding structure design, such as Figure 5 As shown, the tray-type structural design is adopted, which greatly improves the scalability and versatility of the sub-modules and effectively reduces the product development cost; improves the structural strength of the valve group, reduces the difficulty of installing the sub-modules into the valve frame, and improves the feasibility of engineering implementation; adopts a horizontal structural solution, which greatly reduces the overall spatial size of the valve group and is conducive to the electrical connection between sub-modules.

[0082] The converter mainly includes submodules, supporting insulators, conductive busbars, optical cables / optical fibers, maintenance platforms, etc. The conductive busbars and optical cables / optical fibers are connected to the electrical circuit and converter control and protection system respectively.

[0083] Valve container Figure 6As shown in the figure, it is mainly a valve group, with a top-mounted air conditioner on the top and fire auxiliary control systems on both sides. The overall layout of the valve tower takes into account factors such as land occupation, earthquake resistance, and economy. It not only takes into account the needs of aesthetics and electrical design, but also carefully considers many related complex factors, such as creepage distance, air clearance, internal interference, stray inductance, distributed capacitance, weight distribution, ease of installation, maintenance and testing, etc. At the same time, in order to achieve high reliability and long-term safe operation, the selection of structural materials and component design are carefully considered to reduce the risk of fire in the converter.

[0084] The optical cable trough consists of the main optical cable trough and the interlayer optical cable trough, and is made of SMC material. The main optical cable trough leads to the vertical main optical cable trough to each interlayer optical cable trough. The inlet of the optical cable trough is at the same potential as the frame, and the outlet is at the same potential as the ground. The creepage distance of the optical cable trough is >25mm / kV.

[0085] The converter insulation (plastic parts) are made of materials with anti-corona discharge properties. The converter structural design calculates the voltage distribution of each structural part, arranges the structural parts reasonably, and cooperates with the shielding cover to avoid corona discharge during the operation of the converter and reduce the risk of aging of the insulating material due to corona discharge.

[0086] In summary, the electrical design points of the PCS converter of the high-voltage direct-mounted energy storage system in this application are as follows:

[0087] 1) High reliability:

[0088] IGBT drive, heat dissipation, protection coordination and other key technologies to improve reliability;

[0089] A. Based on the optimized coordination of high current density IGBT and autonomous digital drive, the micro-process optimization of IGBT opening and closing is realized, overvoltage stress is reduced, the IGBT operating area is optimized, the current and voltage margins are ensured, the steady-state and transient characteristics are taken into account, and the reliability of the converter is improved;

[0090] B. Digital drive, valve control, and control protection jointly realize multi-level overcurrent protection. Through the coordination of protection setting value, delay and other parameters, it ensures the rapidity of protection while providing excellent fault ride-through capability;

[0091] C. The submodule structure adopts an explosion-proof design, which can isolate the failed components from other components. When the submodule fails, it will not affect the adjacent components of the module, nor will it affect the reliable operation of the adjacent submodules or the entire converter.

[0092] Key technologies of electromagnetic compatibility of modular multi-level topology:

[0093] A. A design method for converter submodules with partition layout and shielding design was proposed and implemented:

[0094] (1) Distinguish interference circuits and sensitive circuits and arrange them in zones;

[0095] (2) Focus on shielding sensitive circuits to reduce mutual electromagnetic coupling and improve anti-interference performance;

[0096] (3) The drive line uses coaxial cable to optimize the drive line path, while taking into account the shutdown characteristics and the consistency of the upper and lower tubes;

[0097] B. The CNAS laboratory we rely on has carried out comprehensive submodule electromagnetic compatibility testing, in which the radio frequency electromagnetic field radiation immunity in the three directions of XYZ is not less than 50V / m;

[0098] C. Through electromagnetic compatibility testing, sensitive ports, secondary lines, and electronic circuits were further identified, and suppression units were installed in a targeted manner. Through multiple flexible AC and DC projects, the reliability of the design was confirmed.

[0099] 2) Compact and easy to maintain:

[0100] Valve tower compact design:

[0101] The inverter structure adopts a modular, supported valve stack design. The designed modules are easy to install and maintain, effectively reducing the inverter's footprint.

[0102] Sub-module multi-stage separation design, easy installation and maintenance:

[0103] The submodule board installation position takes into account the convenience of debugging and maintenance, and can be easily separated from the submodule body; the converter adopts a high-speed vacuum bypass switch to avoid equipment tripping caused by submodule failure, which is convenient for operation and maintenance;

[0104] The submodules based on the slide rails are removable, which is convenient for installation, inspection and maintenance. The converter tower bracket is equipped with parallel rails. The submodules are as a whole. When pushing in and pulling out, there is rolling friction between the chassis and the rails, which makes it easy to push in and pull out.

[0105] Valve control system: platform design, visual development, and convenient maintenance:

[0106] The software is structured and developed visually. It has perfect self-monitoring and alarm functions, which makes it easy for operation and maintenance personnel to find problems with the valve control device. Combined with dual configuration and online maintenance, it can improve the reliability of the valve control system.

[0107] 3) Test capability

[0108] Complete test system and multi-level test verification:

[0109] All type test items of voltage source converters cover the entire range of components, submodules, valve sections, and converters. Including testing of basic devices such as IGBTs and high-speed switches, converter module testing, converter high voltage and high current operation testing, control and protection system testing, and closed-loop verification of the entire system, providing verification means for system research, equipment development, and engineering implementation; building a high junction temperature, non-delay short-circuit test platform with a short-circuit current peak of 60kA and an adjustable waveform to meet the converter short-circuit test requirements; building a flexible AC equipment whole machine access test platform with a voltage of 35kV to fully examine the overall operating performance of the converter, valve control, and control protection. With the help of multi-level test methods, the converter is tested and verified in strict accordance with the test requirements of this project, and the converter equipment is ensured to meet the engineering requirements through test optimization and iteration.

[0110] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0111] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0112] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

Claims

1. A PCS converter, characterized in that: include: A plurality of submodules, each submodule comprising an H-bridge circuit, wherein the H-bridge circuit is composed of four insulated gate bipolar transistors; At least one DC support capacitor and inductor connected to the DC side of the H-bridge circuit for smoothing DC voltage fluctuations; A bypass switch connected in parallel at both ends of the H-bridge circuit is used to isolate the submodule when it fails; The DC interface circuit connected in parallel at both ends of the multiple submodules is used to adjust the input and output of the voltage according to the instructions sent by the control system.

2. The PCS converter according to claim 1, characterized in that: The submodule includes: first to fourth insulated gate bipolar transistors and a diode; wherein, The first insulated gate bipolar transistor and the second insulated gate bipolar transistor are connected in series to form a first bridge arm, the third insulated gate bipolar transistor and the fourth insulated gate bipolar transistor are connected in series to form a second bridge arm, the first bridge arm and the second bridge arm constitute an H-bridge circuit, and the first insulated gate bipolar transistor to the fourth insulated gate bipolar transistor are anti-parallel connected by a diode.

3. The PCS converter according to claim 2, characterized in that: The DC interface circuit comprises: A battery pack, a first switch, a second switch, a resistor and a fuse, wherein: The battery pack is composed of multiple battery cells connected in series, the positive electrode of the battery pack is connected to the second switch and the second switch, the negative electrode of the battery pack is connected to the fuse, the other end of the fuse is connected to a resistor, and the other end of the resistor is connected to the first switch or the second switch according to the switch.

4. The PCS converter according to claim 3, characterized in that: Also includes: A conductive busbar, used to efficiently distribute the DC power to each submodule and aggregate the AC outputs of the submodules; Optical cable assemblies, used to transmit control signals and monitoring data, enable communication between the control system and submodules, and provide electrical isolation; Support insulators are used to mechanically support and electrically isolate the internal components of the converter.

5. The PCS converter according to any one of claims 4, characterized in that: The bypass switch is a relay, the conductive busbar is made of a metal material with low resistivity and good conductivity, and the supporting insulator is made of a high-strength ceramic material.

6. A high-voltage direct-hanging grid-type energy storage system, characterized in that: include: The PCS converter according to any one of claims 1 to 5, used for bidirectional conversion between direct current and alternating current; The control system is used to generate corresponding control instructions according to the grid demand to control the PCS converter to perform target operations.

7. The high-voltage direct-hanging grid-type energy storage system according to claim 6 is characterized in that: The control system includes: a battery management system, a submodule control unit, a valve control module and a power control panel; wherein, The battery management system is connected to the battery pack of the PCS converter and is used to output a corresponding voltage value to match the grid demand, or to store the DC power converted by the PCS converter; The submodule control unit is connected to the multiple submodules of the PCS converter and is used to control the multiple submodules of the PCS converter; The valve control module is in communication with the submodule control unit and is used to send valve control instructions to the submodule control unit according to power grid requirements to control the valve status of each submodule; The power control panel is used to control the charging and discharging power regulation of the high-voltage direct-mounted grid-type energy storage system.

8. The high-voltage direct-mounted grid-type energy storage system according to claim 6 is characterized in that: Also includes: Switches, used for network communication between modules of high-voltage direct-mounted grid-type energy storage systems; The monitoring system is used to monitor the operating status of each module of the high-voltage direct-mounted grid-type energy storage system in real time.

9. The high-voltage direct-hanging grid-type energy storage system according to claim 6 is characterized in that: Also includes: The maintenance platform is used for maintaining and inspecting the internal structure of the converter, wherein the maintenance platform is equipped with safety guardrails and anti-slip floors.

10. A topological structure of a high-voltage direct-mounted grid-type energy storage system, characterized in that: include: container; A plurality of load-bearing frames are arranged inside the container, an energy storage valve group is arranged on the load-bearing frame, and an insulating base is arranged between the energy storage valve group and the container; The bracket of the energy storage valve group is equipped with parallel guide rails, and a tray structure is arranged on the guide rails. A PCS converter and a control system are placed inside the tray structure; The slide-based submodule removable design controls the push-in and pull-out of the submodule board, submodule body, and control system to achieve independent partition layout of each submodule of the converter. Each submodule adopts a primary and secondary partition shielding design to place the primary power circuit and the secondary control system in independent cavities to reduce electromagnetic interference. A roof-mounted air conditioner is arranged on the top of the container, and fire auxiliary control systems are arranged on both sides.

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