Railway flexible traction system based on multi-source fusion

Abstract

The invention provides a railway flexible traction system based on multi-source fusion. The system is composed of a central control unit, a V / v traction transformer unit and a multi-port flexible interconnection unit. The V / v traction transformer unit comprises a first power supply arm, a second power supply arm and a third power supply arm, the input ends of the V / v traction transformer unit are connected with a public power grid, the first and second power supply arms are connected to the multi-port flexible interconnection unit, and the third power supply arm provides passive support for a traction network. The multi-port flexible interconnection unit comprises a two-phase rectification module, a photovoltaic power generation module, an energy storage module and a single-phase inversion module which are commonly connected to a DC bus. The central control unit adjusts the output power of the multi-port flexible interconnection system and the control strategy of the single-phase inversion module in real time so as to realize flexible consumption of new energy and improvement of power supply stability. The system has the advantages of compatibility, cost effectiveness, new energy access and consumption, power supply reliability improvement, electric energy quality optimization, high adaptability and the like, and is suitable for upgrading and reconstruction of newly-built railway lines and existing railway lines.

Description

Technical Field

[0001] The present invention relates to the technical field of railway traction power supply systems, and particularly to a railway flexible traction system based on multi-source fusion. Background Art

[0002] Traditional railway traction power supply systems have many structural defects, such as power supply interruptions caused by phase separators, power quality problems (such as negative sequence current, harmonic interference), and increasing locomotive energy consumption. These problems seriously affect the efficiency, reliability, and economy of railway transportation. With the development of new energy technologies, how to connect new energy systems to railway traction power supply systems and achieve high-quality integrated development has become an important development direction for modern railway traction power supply systems.

[0003] The patent application with the application number 201810934439X discloses an invention patent for an off-grid traction power supply system with multi-energy complementarity based on battery energy storage. Three-phase wind power generation and three-phase photovoltaic power generation cooperate with an energy storage unit to supply power to a three-phase AC bus, and then a traction transformer connected to the three-phase AC bus supplies power to the traction network. However, the resource investment in the three-phase AC bus, three-phase wind power, and photovoltaic power is relatively large.

[0004] However, transforming the existing railway traction power supply system is a large-scale, complex, and costly systematic project. How to balance the transformation cost of the traction line with the power quality and operation benefit requirements of the new line will be the key research direction for the new traction power supply system. At the same time, due to the demand for low-carbon energy conservation in the railway traction power supply system, how to improve the new energy access and consumption capacity of the traction power supply system and build a green and intelligent traction power supply system will also be an important development direction for the modern traction power supply system. Based on the above analysis, the in-phase traction power supply system architecture with multi-source fusion is deeply studied, and a railway flexible traction system based on multi-source fusion is proposed. This system takes into account the transformation cost, power quality problems, and new energy access and consumption requirements, and can completely eliminate the phase separator, improving the power supply reliability of the railway traction power supply system. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a railway flexible traction system based on multi-source fusion to solve the problems existing in the prior art and achieve the efficient, reliable, and low-carbon operation of the railway traction power supply system.

[0006] To solve the above technical problems, in a first aspect, the technical solution adopted by the present invention is a railway flexible traction system based on multi-source fusion, which is composed of a central control unit, a V / v traction transformer unit, and a multi-port flexible interconnection unit:

[0007] The V / v traction transformer unit includes a first power supply arm, a second power supply arm, and a third power supply arm. Its input end is connected to the public power grid. The first power supply arm and the second power supply arm are connected to a multi-port flexible interconnection unit, and the third power supply arm is drawn from the first power supply arm and the second power supply arm to provide passive support for the traction network.

[0008] The multi-port flexible interconnection unit includes a two-phase rectification module, a photovoltaic power generation module, an energy storage module, and a single-phase inversion module that are commonly connected to the DC bus.

[0009] Convert the alternating current of the first power supply arm and the second power supply arm of the V / v traction transformer into direct current and connect it to the DC bus of the multi-port flexible interconnection system.

[0010] Single-phase inversion module: Invert the direct current on the DC bus into single-phase alternating current to provide active support for the traction network, complement the passive output of the third power supply arm of the V / v traction transformer, and improve the operation reliability of the system.

[0011] Photovoltaic power generation module and energy storage module: Each includes a photovoltaic module and an energy storage module, and is incorporated into the DC bus of the multi-port flexible interconnection system through a DC / DC converter. The energy storage module has the function of recovering the braking feedback energy of the locomotive, further optimizing the energy utilization efficiency.

[0012] The central control unit adjusts the output power of the multi-port flexible interconnection system and the control strategy of the single-phase inversion module in real time.

[0013] Optionally, the multi-port flexible interconnection unit has three different topological structure forms to adapt to different application scenarios and requirements.

[0014] Optionally, the two-phase rectification module includes a step-down transformer and a two-phase PWM rectifier. The output ends of the PWM rectifier, the photovoltaic power generation module, and the energy storage module are connected to the common medium-voltage and low-voltage DC bus. The effective value of the output current of the two-phase PWM rectifier is equal to the effective value of the line current of the secondary side ab phase of the V / v traction transformer.

[0015] Optionally, the two-phase rectification module includes a multi-winding transformer and a railway power conditioner (RPC). The multi-winding transformer steps down the 27.5 kV voltage output by the first power supply arm and the second power supply arm of the V / v traction transformer to medium and low voltages. The output ends of the railway power conditioner, the photovoltaic power generation module, and the energy storage module are connected to the common medium-voltage and low-voltage DC bus. The effective value of the output current of the two-phase PWM rectifier is equal to the effective value of the line current of the secondary side ab phase of the V / v traction transformer.

[0016] Optionally, the two-phase rectification module is composed of an MMC-based rectifier, which boosts the 27.5 kV voltage output by the first power supply arm and the second power supply arm to medium-high voltage. The output terminals of the rectifier, the photovoltaic power generation module, and the energy storage module are connected to a common medium-high voltage DC bus. The effective value of the output current of the two-phase PWM rectifier is equal to the effective value of the line current of the ab phase on the secondary side of the V / v traction transformer.

[0017] Optionally, the photovoltaic power generation module includes a photovoltaic array, a DC / DC converter, and a control circuit, and the control circuit adaptively adjusts the output power according to the light conditions.

[0018] Optionally, the energy storage module includes an energy storage battery pack, a bidirectional DC / DC converter, and a battery management system, and the battery management system has overcharge, over-discharge, over-voltage, and over-current protection functions.

[0019] Optionally, the single-phase inverter module adopts inverter technology and control algorithms, and the control algorithms adaptively adjust the output power according to the load changes.

[0020] Optionally, the central control unit includes a data acquisition module, a signal processing module, a control algorithm module, and a communication module, which can collect information such as traction network load data, new energy output power, and energy storage module status in real time, and dynamically adjust the operating parameters of the multi-port flexible interconnection system and the single-phase inverter module through control strategies.

[0021] Optionally, the system supports remote monitoring and operation and maintenance management, and operation and maintenance personnel can remotely obtain system operation data, adjust operation parameters, and perform maintenance operations.

[0022] Optionally, the central control unit also has a fault diagnosis and protection function, which can monitor the system operation status in real time and perform on-line monitoring and fault location.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0024] Compatibility and cost-effectiveness: A new type of flexible traction power supply system is constructed based on the traditional V / v traction transformer, which greatly reduces the construction cost of the new system and is compatible with the original system.

[0025] New energy access and consumption: The centralized access of new energy along the railway and the local utilization of photovoltaic green power are realized, which improves the low-carbon energy-saving ability of the system.

[0026] Improved power supply reliability: Through the active support and passive output complementarity of the multi-port flexible interconnection unit, the electrical phase separation is completely eliminated, and the power supply reliability of the traction power supply system is significantly improved.

[0027] Power quality optimization: The system has a two-way energy transmission function, can recover the energy feedback during locomotive braking, optimize the energy utilization efficiency, and further improve the power supply stability through the flexible adjustment of the central control unit.

[0028] Strong adaptability: The three topological structure forms of the multi-port flexible interconnection unit can be selected according to different application scenarios and requirements, with wide applicability. Brief Description of the Drawings

[0029] Figure 1 Schematic diagram of a railway flexible traction system based on multi-source fusion provided by an embodiment of the present invention;

[0030] Figure 2 Schematic diagram of the architecture of a railway flexible traction system based on multi-source fusion provided by an embodiment of the present invention;

[0031] Figure 3 Topological structure of a multi-port flexible interconnection unit provided by an embodiment of the present invention;

[0032] Figure 4 Another topological structure of a multi-port flexible interconnection unit provided by an embodiment of the present invention;

[0033] Figure 5 Yet another topological structure of a multi-port flexible interconnection unit provided by an embodiment of the present invention;

[0034] Figure 6 Vector operation diagram of a railway flexible traction system based on multi-source fusion provided by an embodiment of the present invention. Detailed Description of the Invention

[0035] Obviously, many modifications and changes made by those skilled in the art based on the purpose of the present invention fall within the protection scope of the present invention.

[0036] Those skilled in the art of this technology can understand that unless specifically stated otherwise, the singular forms "a", "an", "the" and "said" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the description of the present invention means the presence of the stated features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. It should be understood that when an element or component is referred to as being "connected" to another element or component, it can be directly connected to other elements or components, or there may also be intermediate elements or components. The phrase "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment 1:

[0039] In this embodiment, a railway flexible traction system based on multi-source fusion is provided. As Figure 1-2 shown, the system consists of a central control unit, a V / v traction transformer unit, and a multi-port flexible interconnection unit:

[0040] Among them, the V / v traction transformer unit includes a first power supply arm, a second power supply arm, and a third power supply arm. Its input end is connected to the public power grid. The first power supply arm and the second power supply arm are connected to the multi-port flexible interconnection unit. The third power supply arm is drawn from the first power supply arm and the second power supply arm to provide passive support for the traction network.

[0041] Among them, the multi-port flexible interconnection unit includes a two-phase rectification module, a photovoltaic power generation module, an energy storage module, and a single-phase inversion module that are commonly connected to the DC bus. The two-phase rectification module converts the alternating current of the first power supply arm and the second power supply arm of the V / v traction transformer into direct current and accesses the DC bus of the multi-port flexible interconnection unit. The single-phase inversion module inverses the direct current on the DC bus into single-phase alternating current to provide active support for the traction network, which complements the passive output of the third power supply arm of the V / v traction transformer to improve the operation reliability of the system. The photovoltaic power generation module and the energy storage module are respectively incorporated into the DC bus of the multi-port flexible interconnection system through DC / DC converters. The energy storage module has the function of recovering the braking feedback energy of the locomotive to further optimize the energy utilization efficiency.

[0042] Among them, the central control unit realizes the real-time and flexible consumption of the output power of new energy by adjusting the output power of the multi-port flexible interconnection system. At the same time, by adjusting the control strategy of the single-phase inversion module, it improves the inertial damping of its output active and reactive power and enhances the power supply stability of the single-phase traction network.

[0043] The system also adopts a redundant design. When a certain module fails, the standby module can be quickly switched to ensure the uninterrupted operation of the system. The system is equipped with overvoltage, overcurrent, short-circuit and other protection devices. When an abnormality is detected, the central control unit immediately activates the protection mechanism to cut off the faulty module to ensure the safety of the equipment.

[0044] The system also supports remote monitoring and operation and maintenance management. Operation and maintenance personnel can remotely obtain system operation data, adjust operation parameters, and perform maintenance operations.

[0045] The central control unit also has the functions of fault diagnosis and protection, can monitor the system operation status in real time, and perform on-line monitoring and fault location.

[0046] Embodiment 2

[0047] In this embodiment, a railway flexible traction system based on multi-source fusion is provided. The topological structure of its multi-port flexible interconnection unit is as Figure 3 shown. It is applied to a newly built railway line. The main equipment and parameters of the system are as follows:

[0048] V / v traction transformer: The input voltage is 110 kV, and the output voltage is 27.5 kV (for the first power supply arm and the second power supply arm).

[0049] Step-down transformer: Step down the 27.5 kV voltage to 10 kV.

[0050] Two-phase PWM rectifier: Rectify the 10 kV alternating current into a medium and low voltage DC bus (DC Bus) with a voltage level of ±750 V.

[0051] Photovoltaic power generation module: The installed capacity is 500 kW, and it is connected to the DC bus through a DC / DC converter.

[0052] Energy storage module: The capacity is 1 MW / 2 MWh, and it has the function of recovering the locomotive braking feedback energy.

[0053] Single-phase inverter module: It includes a DC / AC converter and a step-up transformer, which invert the ±750 V direct current into 27.5 kV single-phase alternating current to provide active support for the traction network.

[0054] The system operation includes the following stages:

[0055] 1. Initial operation stage:

[0056] Photovoltaic power generation access: When there is sufficient sunlight during the day, the photovoltaic system converts solar energy into direct current, which is connected to the DC bus through a DC / DC converter to provide part of the power supply demand for the traction network.

[0057] Energy storage module pre-charging: The energy storage module is in the pre-charging state in the initial stage to ensure that there is enough energy support when the system starts.

[0058] 2. Normal operation stage

[0059] Two-phase rectification module: After stepping down the 27.5 kV alternating current to 10 kV, it is rectified into ±750 V direct current through a two-phase PWM rectifier to provide stable voltage support for the DC bus.

[0060] Single-phase Inverter Module: According to the load demand of the traction network, it converts the electric energy on the DC bus into single-phase alternating current of 27.5 kV, which complements the passive output of the third power supply arm of the V / v traction transformer to ensure the power supply reliability of the traction network.

[0061] New Energy Absorption: The central control unit monitors the output power of the photovoltaic system and the energy storage module in real time. By adjusting the control strategy of the single-phase inverter module, it flexibly absorbs the output power of new energy and optimizes the system operation.

[0062] 3. Locomotive Brake Feedback Stage

[0063] When the locomotive enters the braking state, the braking feedback energy is transmitted to the single-phase inverter module through the traction network, and the inverted direct current flows back to the DC bus. Under the command of the central control unit, the energy storage module absorbs the braking feedback energy to achieve the reuse of energy and reduce the system energy consumption.

[0064] System Control Strategy: By collecting the traction network load data, new energy output power and energy storage module status in real time, it dynamically adjusts the output power and control strategy of the single-phase inverter module to optimize the system operation efficiency. By adjusting the PWM modulation strategy of the two-phase rectifier module, it reduces the harmonic content and improves the power quality. On the premise of meeting the traction network power supply demand, it preferentially schedules the output power of the photovoltaic system, reduces the dependence on the public power grid, and enhances the low-carbon operation ability of the system.

[0065] Embodiment 3

[0066] In this embodiment, a railway flexible traction system based on multi-source fusion is provided. The topological structure of its multi-port flexible interconnection unit is as Figure 4 shown, and it is applied to the upgrade and transformation of a certain existing railway line. The main equipment and parameters of the system are as follows:

[0067] V / v Traction Transformer: The input voltage is 110 kV, and the output voltage is 27.5 kV (the first power supply arm and the second power supply arm).

[0068] Multi-winding Transformer: It reduces the 27.5 kV voltage to 10 kV.

[0069] Railway Power Conditioner (RPC): It realizes the access of photovoltaic and energy storage through the common medium and low voltage DC bus (DC Bus).

[0070] Photovoltaic Power Generation Module: The installed capacity is 300 kW, and it is connected to the DC bus through a DC / DC converter.

[0071] Energy Storage Module: The capacity is 500 kW / 1 MWh, and it has the function of recovering the locomotive braking feedback energy.

[0072] Single-phase inverter module: It includes a DC / AC converter and a step-up transformer, which invert ±750V DC power into 27.5kV single-phase AC power to provide active support for the traction network.

[0073] The system operation includes the following stages:

[0074] 1. Initial operation stage

[0075] System compatibility test: When upgrading and transforming on the existing railway line, first test the compatibility between the new system and the existing system to ensure seamless docking.

[0076] Energy storage module initialization: The energy storage module is initialized in the initial stage to ensure that it can provide stable energy support when the system starts.

[0077] 2. Normal operation stage

[0078] Multi-winding transformer operation: After stepping down the 27.5kV voltage to 10kV, the photovoltaic and energy storage modules are connected through the Railway Power Conditioner (RPC).

[0079] RPC power regulation: RPC dynamically adjusts the power flow direction according to the real-time load demand and new energy output power to optimize the system operation efficiency.

[0080] Single-phase inverter module: According to the load demand of the traction network, it inverts the electric energy on the DC bus into 27.5kV single-phase AC power, which complements the passive output of the third power supply arm of the V / v traction transformer to ensure the power supply reliability of the traction network.

[0081] 3. Locomotive braking feedback stage

[0082] Energy recovery: When the locomotive enters the braking state, the braking feedback energy is transmitted to the single-phase inverter module through the traction network, and the inverted DC power flows back to the DC bus.

[0083] Energy storage module charging: Under the command of the central control unit, the energy storage module absorbs the braking feedback energy to realize the reuse of energy and reduce the system energy consumption.

[0084] System control strategy: The central control unit dynamically adjusts the output power and control strategy of the single-phase inverter module by collecting real-time traction network load data, new energy output power, and energy storage module status to optimize the system operation efficiency. By adjusting the power regulation strategy of RPC, it optimizes the access and consumption of new energy and reduces the dependence on the public power grid. By adjusting the PWM modulation strategy of the two-phase rectifier module, it reduces the harmonic content and improves the power quality.

[0085] Embodiment 4

[0086] In this embodiment, a railway flexible traction system based on multi-source fusion is provided. The topological structure of its multi-port flexible interconnection unit is as Figure 5 shown. It is applied to the upgrading and transformation of a certain existing railway line. The main equipment and parameters of the system are as follows:

[0087] V / v traction transformer: The input voltage is 220 kV, and the output voltage is 27.5 kV (for the first power supply arm and the second power supply arm).

[0088] MMC-based rectifier: Boosts the 27.5 kV voltage to 35 kV and outputs a medium-high voltage DC bus (DC Bus) with a voltage level of ±17.5 kV.

[0089] Photovoltaic power generation module: The installed capacity is 1 MW, and it is connected to the DC bus through a DC / DC converter.

[0090] Energy storage module: The capacity is 2 MW / 4 MWh, and it has the function of recovering and storing the braking feedback energy of locomotives.

[0091] MMC-based single-phase inverter module: Inverts the ±17.5 kV DC power into 27.5 kV single-phase AC power to provide active support for the traction network.

[0092] The system operation includes the following stages:

[0093] 1. Initial operation stage

[0094] System commissioning: Conduct system commissioning on the high-speed railway line to ensure the coordinated operation of each device.

[0095] Energy storage module pre-charging: The energy storage module is pre-charged in the initial stage to ensure sufficient energy support when the system starts.

[0096] 2. Normal operation stage

[0097] MMC rectifier operation: The MMC-based rectifier boosts the 27.5 kV voltage to 35 kV and outputs a medium-high voltage DC bus to provide a stable access platform for the photovoltaic and energy storage modules.

[0098] Photovoltaic power generation access: The photovoltaic system converts solar energy into DC power and connects it to the DC bus through a DC / DC converter to provide part of the power supply demand for the traction network.

[0099] Single-phase inverter module: According to the load demand of the traction network, it inverts the electric energy on the DC bus into 27.5 kV single-phase AC power, which complements the passive output of the third power supply arm of the V / v traction transformer to ensure the power supply reliability of the traction network.

[0100] New energy consumption: The central control unit monitors the output power of the photovoltaic system and the energy storage module in real time. By adjusting the control strategy of the single-phase inverter module, it flexibly consumes the output power of new energy and optimizes the system operation.

[0101] 3. Locomotive braking feedback stage

[0102] Energy recovery: When the locomotive enters the braking state, the braking feedback energy is transmitted to the single-phase inverter module through the traction network, and the inverted direct current flows back to the DC bus.

[0103] Energy storage module charging: Under the command of the central control unit, the energy storage module absorbs the braking feedback energy, realizes the reuse of energy, and reduces the system energy consumption.

[0104] System control strategy: The central control unit dynamically adjusts the output power and control strategy of the single-phase inverter module by collecting the traction network load data, new energy output power, and energy storage module status in real time, optimizing the system operation efficiency. By adjusting the modulation strategy of the MMC, it optimizes the access and consumption of new energy and reduces the dependence on the public power grid. By adjusting the PWM modulation strategy of the two-phase rectifier module, it reduces the harmonic content and improves the power quality. On the premise of meeting the power supply demand of the traction network, it preferentially schedules the output power of the photovoltaic system, reduces the dependence on the public power grid, and enhances the low-carbon operation ability of the system.

[0105] The railway flexible traction system architecture based on multi-source fusion of the present invention realizes multi-source fusion, new energy access and consumption, power quality optimization, and power supply reliability improvement through three different multi-port flexible interconnection unit topologies. Specific embodiments show the construction, operation, and control strategies of the system in different application scenarios, verifying its technical feasibility and economy. This system is not only applicable to newly built railway lines but also can upgrade and transform existing railway lines, having broad application prospects and significant economic and social benefits.

[0106] Among them, the relationship between the primary current and the secondary current of the V / v transformer is as Figure 6 shown. Assuming the transformer turns ratio is k,, i A , i B , i C are the primary three-phase currents; i ac , i bc are respectively the two-phase output currents of the secondary PWM rectifier, i ab (i L ) is the line current of the secondary ab phase, i Ld is the total load current of this traction substation, i o is the output current of the inverter grid-forming port of the multi-port system. It can be seen from the formula and the vector operation diagram that when the two-phase PWM rectifier output currents (i ac , i bc) The effective value of () is equal to I ab When they are equal, the three-phase currents on the primary side are symmetric and balanced.

[0107] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0108] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in the form of hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0109] Finally, it should also be noted that in this article, relationships such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device.

Claims

1. A railway flexible traction system based on multi-source fusion, consisting of a central control unit, a V / v traction transformer unit and a multi-port flexible interconnection unit, characterized in that: The V / v traction transformer unit comprises a first power supply arm, a second power supply arm and a third power supply arm, wherein the input end thereof is connected to the public power grid, the first power supply arm and the second power supply arm are connected to the multi-port flexible interconnection unit, and the third power supply arm is led out from the first power supply arm and the second power supply arm to provide passive support for the traction network; The multi-port flexible interconnection unit includes a two-phase rectifier module, a photovoltaic power generation module, an energy storage module and a single-phase inverter module which are commonly connected to a DC bus; The central control unit adjusts the output power of the multi-port flexible interconnection system and the control strategy of the single-phase inverter module in real time.

2. The railway flexible traction system based on multi-source fusion according to claim 1 is characterized in that: The two-phase rectifier module includes a step-down transformer and a two-phase PWM rectifier. The output ends of the PWM rectifier, photovoltaic power generation module and energy storage module are connected to a common medium and low voltage DC bus. The effective value of the output current of the two-phase PWM rectifier is equal to the effective value of the line current of the secondary ab phase of the V / v traction transformer.

3. The railway flexible traction system based on multi-source fusion according to claim 1 is characterized in that: The two-phase rectifier module includes a multi-winding transformer and a railway power conditioner (RPC). The multi-winding transformer reduces the 27.5kV voltage output by the first power supply arm and the second power supply arm of the V / v traction transformer to a medium and low voltage. The output ends of the railway power conditioner, photovoltaic power generation module and energy storage module are connected to a common medium and low voltage DC bus. The effective value of the output current of the two-phase PWM rectifier is equal to the effective value of the line current of the secondary ab phase of the V / v traction transformer.

4. The railway flexible traction system based on multi-source fusion according to claim 1 is characterized in that: The two-phase rectifier module is composed of an MMC-based rectifier, which boosts the 27.5kV voltage output by the first power supply arm and the second power supply arm to medium and high voltage. The output ends of the rectifier, photovoltaic power generation module and energy storage module are connected to a common medium and high voltage DC bus. The effective value of the output current of the two-phase PWM rectifier is equal to the effective value of the line current of the secondary ab phase of the V / v traction transformer.

5. A railway flexible traction system based on multi-source fusion according to any one of claims 1 to 4, characterized in that: The photovoltaic power generation module includes a photovoltaic array, a DC / DC converter and a control circuit, and the control circuit adaptively adjusts the output power according to the lighting conditions.

6. A railway flexible traction system based on multi-source fusion according to any one of claims 1 to 4, characterized in that: The energy storage module includes an energy storage battery pack, a bidirectional DC / DC converter and a battery management system. The battery management system has overcharge, over-discharge, overvoltage and overcurrent protection functions.

7. A railway flexible traction system based on multi-source fusion according to any one of claims 1 to 4, characterized in that: The single-phase inverter module adopts an inverter technology and a control algorithm, and the control algorithm adaptively adjusts the output power according to load changes.

8. A railway flexible traction system based on multi-source fusion according to any one of claims 1 to 4, characterized in that: The central control unit includes a data acquisition module, a signal processing module, a control algorithm module and a communication module, which can collect information such as traction network load data, new energy output power and energy storage module status in real time, and dynamically adjust the operating parameters of the multi-port flexible interconnection system and the single-phase inverter module through control strategies.

9. The railway flexible traction system based on multi-source fusion according to claim 1 is characterized in that: The system supports remote monitoring and operation and maintenance management, and operation and maintenance personnel can remotely obtain system operation data, adjust operation parameters and perform maintenance operations.

10. The railway flexible traction system based on multi-source fusion according to claim 1, characterized in that: The central control unit also has fault diagnosis and protection functions, can monitor the system operation status in real time, and perform online monitoring and fault location.

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