Integrated main wiring structure

Abstract

The utility model relates to an integrated main wiring structure, and belongs to the technical field of new energy application. Comprising a modular multilevel converter, a photovoltaic power generation system, a super capacitor and a lithium battery, according to the application, a 35kV medium-voltage direct current system, a photovoltaic power generation system, a super capacitor and a lithium iron phosphate battery realize flexible direct current interconnection through various power electronic converters, and a multi-port alternating current and direct current hybrid power distribution system is constructed. The introduction of the DC system effectively reduces the conversion links of AC and DC, thereby improving the overall efficiency of the system, avoiding the common electric energy quality problem in the AC system, reducing the control complexity, effectively improving the new energy permeability, and providing a solid technical support for the high-quality development of the new energy system.

Description

Technical Field

[0001] This utility model relates to an integrated main wiring structure, belonging to the field of new energy application technology. Background Technology

[0002] Renewable energy has developed rapidly in recent years and plays an important role in addressing global climate change, ensuring power supply security, and guaranteeing sustained and rapid economic and social development. However, due to its inherent randomness, volatility, and intermittency, large-scale grid integration can have adverse effects on power system operation.

[0003] Currently, constructing large-scale coupled energy storage renewable energy systems to mitigate the volatility and intermittency of renewable energy, improve grid connection rates, and promote renewable energy development has become a trend. Various energy storage technologies are also being applied in practice, such as electrochemical energy storage and physical energy storage, among which lithium iron phosphate battery electrochemical energy storage, flywheel energy storage, and supercapacitors are widely used. However, most current DC systems have AC-DC conversion links, resulting in low overall system efficiency, reduced power quality, and increased control complexity. To ensure the stable and economical operation of hybrid energy storage integrated power supply systems, a novel main wiring structure suitable for photovoltaic and hybrid energy storage integration is proposed. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an integrated main wiring structure to solve the problem that most current DC systems have AC-DC conversion links, resulting in low overall system efficiency and reduced power quality.

[0005] To solve the above-mentioned technical problems, this utility model is implemented using the following technical solution:

[0006] An integrated main wiring structure includes:

[0007] Modular multilevel converters, photovoltaic power generation systems, supercapacitors, and lithium batteries;

[0008] The modular multilevel converters are connected back-to-back.

[0009] The photovoltaic power generation system is connected to the DC bus via a low-voltage DC / DC converter and an isolated DC transformer.

[0010] The supercapacitor is connected to the DC bus via a modular series-connected medium-voltage chain converter.

[0011] The lithium battery is connected to the DC bus via a modular series-connected medium-voltage cascaded converter.

[0012] Furthermore, the modular multilevel converter includes two units, with the AC side of the modular multilevel converter connected to the photovoltaic power generation system and the lithium battery respectively, and the DC side of the modular multilevel converter connected to the supercapacitor and the photovoltaic power generation system via a ±5kV DC bus.

[0013] like Figure 6 As shown, a power regulator employing a back-to-back Modular Multilevel Converter (MMC) structure is modeled. Based on its conventional mathematical model of time domain → αβ coordinates → dq rotating coordinates, a second-order generalized integral is used to construct an orthogonal virtual component along the β-axis to complete the transformation process. Furthermore, a small-signal model of the MMC is established, providing guidance for controller design through an accurate small-signal model.

[0014] The MMC consists of multiple sub-modules, each of which is relatively independent and can be controlled and maintained independently. The MMC adopts a hybrid sub-module topology, which can complete fault ride-through and system voltage reconstruction when a bipolar short circuit occurs in a multi-terminal DC distribution network. During the fault, the MMC does not need to be locked out of the grid. The hybrid sub-module topology of the MMC can complete fault ride-through and system voltage reconstruction when a bipolar short circuit occurs in a multi-terminal DC distribution network. During the fault, the MMC does not need to be locked out of the grid, which improves the operational reliability of the DC system.

[0015] Furthermore, the photovoltaic power generation system is connected to a 750V DC bus via a low-voltage DC / DC converter, and the 750V DC bus is stepped up to a ±5kV DC bus via an isolated DC transformer. For the DC modules in the front-end of the system, a built-in transformer and a built-in transformer voltage multiplier unit are used to achieve high-gain and high-efficiency conversion. For the inverter modules in the rear-end of the system, which are connected in parallel, linear power control is used to improve the dynamic performance of the system and enhance its stability and reliability. The transformer is embedded in a traditional interleaved parallel Boost AC converter to form a non-isolated high-gain AC converter. By reconstructing the rectifier structure commonly used in isolated converters, a built-in transformer structure is derived as a voltage gain extension unit.

[0016] Furthermore, the modular multilevel converter is installed in the core location, while the photovoltaic power generation system is located in an area far from the core location and its access point is close to the low-voltage side of the DC bus.

[0017] Furthermore, the medium-voltage chain converter includes multiple medium-voltage chain converter modules, which are connected in series and then connected to a 5kV DC bus.

[0018] Furthermore, the input end of the medium-voltage chain converter module is connected to a supercapacitor cluster via a high-voltage box. The supercapacitor cluster is composed of multiple supercapacitor groups connected in series, and the supercapacitor group is composed of multiple supercapacitor cells connected in series and parallel.

[0019] Each supercapacitor bank is equipped with a supercapacitor management submodule.

[0020] The supercapacitor system operates at a voltage level of ±5kV, with a rated power of 2MW and an energy storage capacity of 15kWh (30 seconds). The 2MW / 15kWh supercapacitor system consists of a centralized compartment containing a control cabinet, local monitoring cabinet, DC switch cabinet, high-voltage DC power modules, supercapacitor clusters, a battery management system, and a fire suppression system. Each supercapacitor cluster is connected to a power module via a high-voltage box. Internally, it comprises nine supercapacitor modules, each equipped with a supercapacitor management submodule (CMU). These nine supercapacitor modules are connected in series to form a cluster. The positive and negative terminals of the cluster are connected to the positive and negative terminals of the high-voltage box circuit breaker, respectively.

[0021] Furthermore, the medium-voltage cascaded converter includes multiple medium-voltage chain converter modules, which are connected in series to a 5kV DC bus.

[0022] Furthermore, the input terminal of the medium-voltage cascaded converter is connected to a lithium iron phosphate battery cluster via a high-voltage box. The lithium iron phosphate battery cluster is composed of multiple lithium iron phosphate battery packs connected in series, and the lithium iron phosphate battery packs are composed of multiple lithium iron phosphate battery cells connected in series and parallel.

[0023] The 2.5MW / 3MWh lithium battery energy storage system has a voltage rating of ±5kV, a rated power of 2.5MW, and a storage capacity of 3MWh. It consists of a centralized DC cascaded energy storage module, including a control cabinet, local monitoring cabinet, DC switch cabinet, high-voltage DC power valve body, battery clusters, battery management system, and fire protection system. It also employs a medium-voltage DC cascaded energy storage converter, composed of 14 cascaded power modules. Each power module includes a half-bridge arm and an LC filter to reduce voltage and current ripple on the battery side. On the high-voltage side, an energy storage inductor Ls and a supporting capacitor Cs are included to smooth DC-side fluctuations. The lithium batteries are distributed across the power modules, avoiding concentrated cell accumulation at the DC electrode.

[0024] Based on the most advanced AC / DC hybrid power distribution network technology, photovoltaic power generation, supercapacitors and lithium batteries are interconnected flexibly via various power electronic converters to form a multi-port AC / DC hybrid power distribution system. The system can achieve three operating modes: grid-connected operation mode, off-grid operation mode and system shutdown operation mode.

[0025] In the dual-end grid-connected operation mode, both MMC converters in the AC / DC hybrid power distribution system operate in grid-connected mode, and the ±5kV DC bus voltage can be controlled by the MMC or DC cascaded energy storage converter. When one of the two AC grids loses power, the system operates in single-end grid-connected mode. In the off-grid operation mode, both MMC converters in the AC / DC hybrid power distribution system operate in VF mode and supply power to the corresponding AC lines, and the ±5kV DC bus voltage is controlled by the DC cascaded energy storage converter.

[0026] Compared with the prior art, the beneficial effects achieved by this utility model are as follows:

[0027] 1. This application provides an integrated main wiring structure that flexibly interconnects a 35kV medium-voltage DC system, photovoltaic power generation, supercapacitors, and lithium iron phosphate batteries through various power electronic converters, constructing a multi-port AC / DC hybrid power distribution system. The introduction of the DC system effectively reduces AC / DC conversion links, thereby improving the overall system efficiency, avoiding common power quality problems in AC systems, reducing control complexity, effectively increasing the penetration rate of new energy sources, and providing solid technical support for the high-quality development of new energy systems.

[0028] 2. This application realizes the high-voltage DC interconnection of photovoltaic and hybrid energy storage systems, improves power distribution efficiency by reducing AC-DC conversion links, and adopts modular multilevel converter (MMC) technology; at the same time, it directly connects supercapacitors and lithium batteries to the high-voltage DC bus through a modular series high-voltage chain converter, which improves the reliability and energy efficiency of the system, and also provides a new application mode for physical energy storage.

[0029] 3. This application adopts a modular chain converter topology, which not only makes voltage level optimization easier but also allows for more flexible capacity adjustment. This structure is highly scalable, can adapt to different application needs and scales, and has good scalability. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This utility model provides a main wiring diagram of an integrated main wiring structure;

[0032] Figure 2This utility model provides an integrated main wiring structure, including a DC cascaded lithium battery energy storage wiring diagram in the main wiring diagram.

[0033] Figure 3 This utility model provides an integrated main wiring structure, and the main wiring diagram of the isolated PV DC transformer is shown in the diagram.

[0034] Figure 4 This utility model provides an integrated main wiring structure, and the main wiring diagram shows the DC cascaded supercapacitor energy storage wiring diagram.

[0035] Figure 5 This utility model provides a back-to-back multi-port DC topology wiring diagram in the main wiring diagram of an integrated main wiring structure.

[0036] Figure 6 This utility model provides a schematic diagram of the topology of an MMC power valve group with an integrated main wiring structure;

[0037] Figure 7 This utility model provides a schematic diagram of a medium-voltage DC cascaded energy storage converter with an integrated main wiring structure.

[0038] Figure label:

[0039] 1. 35kV grid connection point; 2. First current transformer; 3. First circuit breaker; 4. Bypass switch; 5. First grounding switch; 6. First voltage transformer; 7. MMC matching transformer; 8. MMC submodule; 9. MMC (Modular Multilevel Converter) topology; 10. DC bus; 11. Second grounding switch; 12. Surge arrester; 13. Live indicator; 14. First disconnecting switch; 15. Contactor; 16. Precharge resistor; 17. Electronic voltage and current transformers; 18. Cascaded energy storage system; 19. Medium-voltage cascaded converter; 20. Photovoltaic power generation system; 21. Isolated DC transformer; 22. Supercapacitor system. Detailed Implementation

[0040] The technical solutions of this disclosure / application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure / application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure / application or its application or use. Example

[0041] like Figure 1-5As shown, this embodiment provides an integrated main wiring structure, including: a modular multilevel converter, a photovoltaic power generation system, a supercapacitor, and a lithium battery;

[0042] The modular multilevel converters are connected back-to-back.

[0043] The photovoltaic power generation system is connected to the DC bus via a low-voltage DC / DC converter and an isolated DC transformer.

[0044] The supercapacitor is connected to the DC bus via a modular series-connected medium-voltage chain converter.

[0045] The lithium battery is connected to the DC bus via a modular series-connected medium-voltage cascaded converter.

[0046] The modular multilevel converter includes two units. The AC side of the modular multilevel converter is connected to the photovoltaic power generation system and the lithium battery, respectively. The DC side of the modular multilevel converter is connected to the supercapacitor and the photovoltaic system through a ±5kV DC bus.

[0047] A power regulator employing a back-to-back Modular Multilevel Converter (MMC) structure was modeled. Based on its conventional mathematical model of time-domain → αβ coordinates → dq rotating coordinates, a second-order generalized integral was used to construct an orthogonal virtual component along the β-axis to complete the transformation process. Furthermore, a small-signal model of the MMC was established, providing guidance for controller design through an accurate small-signal model.

[0048] The MMC (Multi-Module Control) consists of multiple independent submodules, each capable of separate control and maintenance. Employing a hybrid submodule topology, the MMC can achieve fault ride-through and system voltage reconstruction during bipolar short circuits in multi-terminal DC distribution networks without requiring the MMC to be locked out of the grid, thus improving the operational reliability of the DC system. In the MMC converter, each arm of the power valve group comprises half full-bridge modules and half-bridge modules, structurally arranged centrally according to module type.

[0049] like Figure 3As shown, the photovoltaic power generation system is connected to a 750V DC bus via a low-voltage DC / DC converter. The 750V DC bus is then stepped up to a ±5kV DC bus via an isolated DC transformer. For the front-end DC modules, a built-in transformer and a built-in transformer voltage multiplier unit are used to achieve high-gain and high-efficiency conversion. For the rear-end inverter modules connected in parallel, linear power control is used to improve the system's dynamic performance, stability, and reliability. The transformer is embedded in a traditional interleaved parallel Boost AC converter to form a non-isolated high-gain AC converter. By reconstructing the rectifier structure commonly used in isolated converters, a built-in transformer structure is derived as a voltage gain extension unit.

[0050] The modular multilevel converter is installed in the core location, while the photovoltaic power generation system is located in an area far from the core location and its access point is close to the low-voltage side of the DC bus.

[0051] The medium-voltage chain converter includes multiple medium-voltage chain converter modules, which are connected in series and then connected to a 5kV DC bus.

[0052] The input terminal of the medium-voltage chain converter module is connected to a supercapacitor cluster via a high-voltage box. The supercapacitor cluster is composed of multiple supercapacitor groups connected in series, and the supercapacitor group is composed of multiple supercapacitor cells connected in series and parallel.

[0053] Each supercapacitor bank is equipped with a supercapacitor management submodule.

[0054] like Figure 4 As shown, the supercapacitor system has a voltage level of ±5kV, a rated power of 2MW, and an energy storage capacity of 15kWh (30 seconds). The 2MW / 15kWh supercapacitor system consists of a centralized compartment containing a control cabinet, a local monitoring cabinet, a DC switch cabinet, high-voltage DC power modules, supercapacitor clusters, a battery management system, and a fire protection system. Each supercapacitor cluster is connected to a power module via a high-voltage box. Internally, it contains nine supercapacitor modules, each equipped with a supercapacitor management submodule (CMU). The nine supercapacitor modules are connected in series to form a cluster. The positive and negative terminals of the cluster are connected to the positive and negative terminals of the high-voltage box circuit breaker, respectively.

[0055] The supercapacitor management system (CMS) adopts a three-level architecture design consisting of a supercapacitor management unit (CMU), a supercapacitor cluster management unit (CCM), and a supercapacitor centralized management unit (CAM), enabling efficient management of four layers of supercapacitors: individual supercapacitors, supercapacitor modules, supercapacitor clusters, and single-phase supercapacitor systems.

[0056] like Figure 2As shown, the medium-voltage cascaded converter includes multiple medium-voltage chain converter modules, which are connected in series to a 5kV DC bus.

[0057] The input terminal of the medium-voltage cascaded converter is connected to a lithium iron phosphate battery cluster via a high-voltage box. The lithium iron phosphate battery cluster is composed of multiple lithium iron phosphate battery packs connected in series, and the lithium iron phosphate battery packs are composed of multiple lithium iron phosphate battery cells connected in series and parallel.

[0058] A medium-voltage DC cascaded energy storage converter is used for the control and management of charging and discharging of the energy storage components. The medium-voltage DC cascaded energy storage converter operates in two modes: grid-connected and off-grid. In grid-connected operation, it operates in power mode and can receive power commands from the monitoring system or energy management system. In off-grid operation, it provides voltage support to the bus and operates in constant voltage or constant current mode. The circuit topology of the medium-voltage DC cascaded energy storage converter is as follows: Figure 7 As shown, it consists of 14 cascaded power modules. Each power module includes a half-bridge arm and an LC filter to reduce voltage and current ripple on the energy storage battery side. On the high-voltage side, an energy storage inductor Ls and a supporting capacitor Cs are included to smooth DC-side fluctuations.

[0059] The lithium battery energy storage system has a voltage rating of ±5kV. It consists of a centralized DC cascaded energy storage module, including a control cabinet, local monitoring cabinet, DC switch cabinet, high-voltage DC power valve body, battery clusters, battery management system, and fire protection system. It also employs a medium-voltage DC cascaded energy storage converter, composed of 14 cascaded power modules. Each power module includes a half-bridge arm and an LC filter to reduce voltage and current ripple on the battery side. On the high-voltage side, an energy storage inductor Ls and a supporting capacitor Cs are included to smooth DC-side fluctuations. The lithium batteries are distributed across the power modules, avoiding concentrated cell accumulation at the DC electrode.

[0060] like Figure 5 As shown, based on the most advanced AC / DC hybrid distribution network technology, photovoltaic power generation, supercapacitors and lithium batteries are interconnected by a variety of power electronic converters to form a multi-port AC / DC hybrid distribution system. The system can realize three operating modes: grid-connected operation mode, off-grid operation mode and system shutdown operation mode.

[0061] In the dual-end grid-connected operation mode, both MMC converters in the AC / DC hybrid power distribution system operate in grid-connected mode, and the ±5kV DC bus voltage can be controlled by the MMC or DC cascaded energy storage converter. When one of the two AC grids loses power, the system operates in single-end grid-connected mode. In the off-grid operation mode, both MMC converters in the AC / DC hybrid power distribution system operate in VF mode and supply power to the corresponding AC lines, and the ±5kV DC bus voltage is controlled by the DC cascaded energy storage converter.

[0062] In dual-end grid-connected operation mode, both MMC converters in the AC / DC hybrid distribution system operate in grid-connected mode, and the ±5kV DC bus voltage can be controlled by the MMC or DC cascaded energy storage converter. In modes 1 and 2, one MMC converter operates in VdcQ mode, controlling the ±5kV DC bus voltage; the other MMC converter operates in PQ mode, controlling the active and reactive power on the AC side; the DC cascaded energy storage operates in power control mode to smooth power fluctuations caused by photovoltaic power generation; and the photovoltaic DC transformer operates in low-voltage side voltage control mode. In mode 3, the DC cascaded lithium-ion battery energy storage controls the ±5kV DC bus voltage, and both MMCs operate in PQ mode, which can regulate the active power of the AC systems on both sides and perform reactive power compensation.

[0063] Table 1: Dual-end grid-connected operation mode

[0064]

[0065] When one of the two AC grids loses power, the system operates in single-end grid-connected mode. In the AC / DC hybrid distribution system, one MMC converter operates grid-connected, while the other operates off-grid in VF mode, supplying power to the corresponding AC line. The ±5kV DC bus voltage can be controlled by the MMC or DC cascaded energy storage converter. In modes 4 and 5, one MMC converter operates in VdcQ mode, controlling the ±5kV DC bus voltage, while the other MMC converter is shut down. The DC cascaded energy storage operates in power control mode to smooth power fluctuations caused by photovoltaic power generation. The photovoltaic DC transformer operates in low-voltage side voltage control mode. In modes 6 and 7, the DC cascaded lithium-ion energy storage controls the ±5kV DC bus voltage, and one MMC operates in PQ mode, which can regulate the active power of the AC systems on both sides and perform reactive power compensation.

[0066] Table 2: Single-End Grid Connection Mode

[0067]

[0068] In off-grid operation mode, both MMC converters in the AC / DC hybrid power distribution system operate in VF mode and supply power to the corresponding AC lines. The ±5kV DC bus voltage is controlled by the DC cascaded energy storage converter. The DC cascaded supercapacitor energy storage operates in power control mode to smooth out power fluctuations caused by photovoltaic power generation. The photovoltaic DC transformer operates in low-voltage side voltage control mode.

[0069] Table 3: Off-grid Operation Mode

[0070]

[0071] The shutdown operation mode is when all equipment in the AC / DC hybrid power distribution system is in a shutdown state.

[0072] The following control functions are achieved through this traction station control system:

[0073] The system includes braking energy recovery, energy sharing, reactive power compensation, enhanced photovoltaic absorption capacity, and off-grid power supply assurance. Braking energy recovery involves timely recovery of the energy generated by locomotive braking into an overcapacitive or lithium battery energy storage system. Energy sharing allows for back-to-back energy sharing between locomotives on different lines if one line brakes while another line starts. Reactive power compensation allows a single-ended MMC to provide reactive power compensation to the AC system, with adjustable inductive and capacitive characteristics. Enhanced photovoltaic absorption capacity involves the rational allocation of power and energy storage based on distributed photovoltaic systems and load conditions. Off-grid power supply assurance ensures that when the traction substation is without grid power, the DC bus voltage can be maintained through a lithium battery energy storage system, and power can then be supplied through a dual-ended MMC AC system.

[0074] like Figure 5 As shown, the 35kV grid connection point is the interface connecting the entire system to the external power grid. The first current transformer monitors the current and provides protection data. The first circuit breaker is used for circuit safety isolation and fault interruption. The bypass switch can skip specific equipment and continue operation during system maintenance or faults. The first grounding switch is used to protect the equipment grounding and prevent power damage.

[0075] The first voltage transformer detects the system voltage. The core equipment in the back-to-back structure is the MMC modular multilevel converter and its matching MMC transformer, which is responsible for efficient AC to DC power conversion and regulation. It is connected to the ±5kV DC bus for DC power distribution. The second grounding switch provides grounding protection for the bus. The surge arrester protects the DC bus and equipment from lightning current. The live display monitors the live status of the equipment. The first disconnecting switch achieves safe electrical isolation from the system.

[0076] like Figure 2 As shown, the DC cascaded lithium battery energy storage system is connected to the ±5kV DC bus through a medium-voltage cascaded converter. The system employs a modular series design, with a pre-charge resistor used to suppress inrush current during startup, and a contactor responsible for connecting and disconnecting the circuit. Electronic voltage and current transformers accurately monitor the current and voltage of the lithium battery energy storage to ensure safe operation. The modular design of the cascaded energy storage system improves flexibility and efficiency, enabling rapid response to grid demands.

[0077] In the description of this disclosure / application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this disclosure / application based on the specific circumstances.

[0078] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this disclosure / application, and these improvements and modifications should also be considered within the protection scope of this disclosure / application.

Claims

1. An integrated main wiring structure, characterized in that, This includes modular multilevel converters, photovoltaic power generation systems, supercapacitors, and lithium batteries; The modular multilevel converters are connected back-to-back. The photovoltaic power generation system is connected to the DC bus via a low-voltage DC / DC converter and an isolated DC transformer. The supercapacitor is connected to the DC bus via a modular series-connected medium-voltage chain converter. The lithium battery is connected to the DC bus via a modular series-connected medium-voltage cascaded converter.

2. The integrated main wiring structure according to claim 1, characterized in that, The modular multilevel converter includes two units. The AC side of the modular multilevel converter is connected to the photovoltaic power generation system and the lithium battery, respectively. The DC side of the modular multilevel converter is connected to the supercapacitor and the photovoltaic power generation system through a ±5kV DC bus.

3. The integrated main wiring structure according to claim 1, characterized in that, The photovoltaic power generation system is connected to a 750V DC bus via a low-voltage DC / DC converter, and the 750V DC bus is stepped up to a ±5kV DC bus via an isolation DC transformer.

4. The integrated main wiring structure according to claim 1, characterized in that, The modular multilevel converter is installed in the core location, while the photovoltaic power generation system is located in an area far from the core location and its access point is close to the low-voltage side of the DC bus.

5. The integrated main wiring structure according to claim 1, characterized in that, The medium-voltage chain converter includes multiple medium-voltage chain converter modules, which are connected in series and then connected to a 5kV DC bus.

6. The integrated main wiring structure according to claim 5, characterized in that, The input terminal of the medium-voltage chain converter module is connected to a supercapacitor cluster via a high-voltage box. The supercapacitor cluster is composed of multiple supercapacitor groups connected in series, and the supercapacitor group is composed of multiple supercapacitor cells connected in series and parallel. Each supercapacitor bank is equipped with a supercapacitor management submodule.

7. The integrated main wiring structure according to claim 1, characterized in that, The medium-voltage cascaded converter includes multiple medium-voltage chain converter modules, which are connected in series to a 5kV DC bus.

8. The integrated main wiring structure according to claim 7, characterized in that, The input terminal of the medium-voltage cascaded converter is connected to a lithium iron phosphate battery cluster via a high-voltage box. The lithium iron phosphate battery cluster is composed of multiple lithium iron phosphate battery packs connected in series, and the lithium iron phosphate battery packs are composed of multiple lithium iron phosphate battery cells connected in series and parallel.

Images