Modularized bidirectional plugging DC-DC topological combination system and management method

Abstract

The invention discloses a modularized bidirectional plugging DC-DC topological combination system and a management method. The system comprises a plurality of sub-modules with the same structure, high and low voltage side voltage-sharing and current-sharing modules connected with the sub-modules, and a sub-module number monitoring module. The sub-modules adopt bidirectional symmetrical isolated DC-DC converters, high-voltage side DC ports of the sub-modules are connected in series to a high-voltage DC bus, and low-voltage side DC ports of the sub-modules are connected in parallel to a low-voltage DC bus; the primary side and the secondary side of each submodule are respectively and symmetrically provided with two voltage-sharing current-sharing feedforward error input ports, the high-voltage-side voltage-sharing feedforward error input port is connected with the high-voltage-side voltage-sharing module, the low-voltage-side current-sharing feedforward error input port is connected with the low-voltage-side current-sharing module, voltage and current error correction signals are received and corrected, and voltage sharing and current sharing of the submodules are achieved. The high-voltage side input voltage sharing and the low-voltage side output current sharing of the sub-modules can be realized while bidirectional plugging is realized, and the energy transmission efficiency, the reliability and the flexibility are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct current energy conversion, and particularly relates to a modular bidirectional plug-in DC-DC topology combination system and a management method. BACKGROUND

[0002] Various bidirectional direct current transmission scenarios such as charging piles of electric vehicles or energy storage devices need to undergo bidirectional conversion of direct current-direct current, and bidirectional resonant converters are widely used in vehicle charging piles due to high efficiency and low cost. With the gradual increase of voltage and power levels, multiple bidirectional resonant topologies need to be used in series and parallel.

[0003] Traditional direct current converters mostly use single, high-power bidirectional isolated DC-DC converters. This structure has obvious limitations, such as poor flexibility, high maintenance cost, and low reliability. In actual photovoltaic storage applications, a single bidirectional DC-DC converter cannot feed back the energy of low-voltage side energy storage batteries to the high-voltage bus for use by other loads, limiting the flexibility of system energy management. In order to solve the capacity and redundancy problems, there is a scheme in the prior art that simply connects multiple bidirectional isolated DC-DC converter modules in parallel. However, due to the differences in electrical parameters of components and devices in traditional bidirectional DC-DC converters, this scheme can cause some modules to be overloaded and generate a lot of heat, while the utilization rate of some modules is insufficient, all because the voltage and current balancing energy control strategy is often complex. SUMMARY

[0004] The first purpose of the present application is to provide a modular bidirectional plug-in DC-DC topology combination system, which realizes flexible expansion of system capacity, high reliable operation and efficient energy management through modular symmetrical DC topology and intelligent voltage and current balancing control management. The second purpose of the present application is to provide a management method of the modular bidirectional plug-in DC-DC topology combination system.

[0005] Technical scheme: The modular bidirectional plug-in DC-DC topology combination system comprises a plurality of sub-modules with the same structure, a high-voltage side voltage balancing module, a low-voltage side current balancing module and a sub-module number monitoring module connected with the sub-modules. The sub-modules adopt bidirectional symmetric isolation type DC-DC converters, have symmetric physical interfaces and support bidirectional plugging operations; the sub-modules have two DC ports of high-voltage side and low-voltage side, the high-voltage side DC ports of each sub-module are connected in series to a high-voltage DC bus, and the low-voltage side DC ports are connected in parallel to a low-voltage DC bus; the primary and secondary sides of the sub-modules are symmetrically provided with two voltage and current equalization feedforward error input ports respectively, when the sub-modules are bidirectionally plugged, the high-voltage side of the sub-modules is the voltage equalization feedforward error input port, the voltage equalization feedforward error input port is connected with a high-voltage side voltage equalization module, and the low-voltage side of the sub-modules is the current equalization feedforward error input port, the current equalization feedforward error input port is connected with a low-voltage side current equalization module; The high-voltage side voltage equalization module inputs the voltage error correction signals of each sub-module into the voltage equalization feedforward error input ports of the corresponding sub-modules based on the number of sub-modules in use to realize the series voltage equalization of the input voltages of the high-voltage side of the sub-modules; and the low-voltage side current equalization module inputs the current error correction signals of each sub-module into the current equalization feedforward error input ports of the corresponding sub-modules based on the number of sub-modules in use to realize the parallel current equalization of the output currents of the low-voltage side of the sub-modules. The sub-module number monitoring module is used for monitoring the number of sub-modules in use in real time and feeding back the number to the high-voltage side voltage equalization module and the low-voltage side current equalization module.

[0006] Preferably, the sub-modules are at least two.

[0007] Preferably, the high-voltage DC bus comprises a high-voltage DC power grid, and the low-voltage DC bus comprises a low-voltage charging and discharging device.

[0008] Preferably, the sub-module number monitoring module comprises an accumulator and a sensor for monitoring the access state of the sub-module.

[0009] Preferably, the high-voltage side voltage equalization module inputs the voltage error correction signals of each sub-module into the voltage equalization feedforward error input ports of the corresponding sub-modules, which comprises that the high-voltage side voltage equalization module collects the input voltage signals of the high-voltage side DC ports of each sub-module in real time and compares the input voltage signals with an ideal voltage average value of the sub-modules, the difference is output as the voltage error correction signals of each sub-module after PID adjustment, the voltage error correction signals are received by the corresponding high-voltage side voltage equalization feedforward error input ports, and the high-voltage side input voltage of the sub-module is continuously adjusted according to the feedback voltage error correction signals, so that the high-voltage side input voltage of the single sub-module after adjustment is the ideal voltage average value, and the high-voltage side input voltages of the sub-modules are equalized.

[0010] Preferably, the low-voltage side current sharing module inputs the current error correction signal of each sub-module into the current sharing pre-feed error input port of the corresponding sub-module, including that the low-voltage side current sharing module collects the output current signal of the low-voltage side direct current port of each sub-module in real time and compares with the ideal current average value of the sub-module, and the difference is output as the current error correction signal of each sub-module after PID adjustment, and is received by the corresponding low-voltage side current sharing pre-feed error input port, and each sub-module continuously adjusts the low-voltage side output current according to the feedback current error correction signal, so that the adjusted low-voltage side output current of the single sub-module is the ideal current average value, and the low-voltage side output current sharing of each sub-module is realized.

[0011] The management method of the modular bidirectional plug-in DC-DC topology combination system comprises the following steps: (1) According to the different output power parameters, the sub-modules are switched according to the input power characteristics and the output power requirements, and the sub-module quantity monitoring module monitors the number of sub-modules in use in real time and feeds back to the high-voltage side voltage sharing module and the low-voltage side current sharing module; (2) The high-voltage side voltage sharing module and the low-voltage side current sharing module collect the input voltage of the high-voltage side port and the output current of the low-voltage side port of each sub-module, and compare the number of sub-modules in use with the ideal voltage average value and the ideal current average value, and then obtain two groups of pre-feed error correction signals which are transmitted to the voltage sharing pre-feed error input port and the current sharing pre-feed error input port of each sub-module; (3) The sub-modules continuously adjust the high-voltage side input voltage and the low-voltage side output current according to the feedback error correction signal, so as to realize the high-voltage side input voltage sharing and the low-voltage side output current sharing after bidirectional plug-in.

[0012] Preferably, the sub-module quantity monitoring module monitoring the number of sub-modules in use in real time comprises that the sensor feedback 1 signal monitoring the sub-module access state when the sub-module is inserted and the feedback 0 signal when the sub-module is cut out are fed back to the accumulator, and the accumulator accumulates the signals to generate the actual number of sub-modules in use.

[0013] Preferably, the high-voltage side voltage sharing module collects the input voltage signal of the high-voltage side direct current port of each sub-module ， and compares with the ideal voltage average value, and the voltage error correction signal of each sub-module is output after PID adjustment, and finally the voltage error correction signal is received by the voltage sharing pre-feed error port of each sub-module in use, and the error of the high-voltage side input voltage from each sub-module is continuously corrected, so that the high-voltage side input voltage of each sub-module reaches the ideal voltage average value.

[0014] Preferably, the low-voltage side current sharing module collects the output current signals of the low-voltage side direct current ports of each sub-module, and compares them with the ideal current average value, and outputs the current error correction signals of each sub-module through the PID adjustment, and finally receives the current error correction signals by the current sharing feedforward error input port of each sub-module in use, so as to continuously correct the low-voltage side current error output by each sub-module, so that the low-voltage side current output by each sub-module reaches the ideal current average value.

[0015] Advantages: Compared with the prior art, the present application has the following remarkable advantages: the present application adopts bidirectional symmetric isolation type DC-DC converter sub-modules, the high-voltage side direct current ports of each sub-module are connected in series to the high-voltage direct current bus, and the low-voltage side direct current ports are connected in parallel to the low-voltage direct current bus, the sub-modules are switched according to the input power characteristics and the output power requirements, the number of sub-modules in use is monitored by the sub-module number monitoring module and fed back to the high-voltage side voltage sharing module and the low-voltage side current sharing module, the high-voltage side voltage sharing module and the low-voltage side current sharing module collect the input voltage of each sub-module high-voltage side port and the output current of each sub-module low-voltage side port, and obtain two groups of feedforward error correction signals based on the comparison of the number of sub-modules in use and the ideal voltage average value and the ideal current average value, and transmit them to the voltage sharing feedforward error input port and the current sharing feedforward error input port of each sub-module, respectively, the sub-modules continuously adjust the high-voltage side input voltage and the low-voltage side output current according to the feedback error correction signals, so as to realize the bidirectional plug-in of the modular bidirectional direct current converter, automatically realize the voltage sharing of the high-voltage side series module and the current sharing of the low-voltage side parallel module, and achieve efficient energy transmission between the high-voltage direct current port and the low-voltage direct current port, flexible modular combination and expansion; through the modular symmetric direct current topology and the intelligent voltage and current sharing control management, the flexible expansion of the system capacity, the high-reliability operation and the efficient energy management are realized. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structural schematic diagram of the present application; Figure 2 is a working flow chart of the sub-module number monitoring module of the present application; Figure 3 is a working principle diagram of the high-voltage side voltage sharing module and the low-voltage side current sharing module of the present application; wherein (a) represents the working flow chart of the high-voltage side voltage sharing module, and (b) represents the working flow chart of the low-voltage side current sharing module; Figure 4 is a low-voltage side current sharing simulation experiment waveform diagram of the three sub-module combination topology in the embodiment of the present application; Figure 5 is a high-voltage side voltage sharing simulation experiment waveform diagram of the three sub-module combination topology in the embodiment of the present application. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0018] like Figure 1 As shown, the modular bidirectional pluggable DC-DC topology combination system of the present invention includes several structurally identical sub-modules, a high-voltage side voltage equalization module, a low-voltage side current equalization module, and a sub-module quantity monitoring module.

[0019] The submodule comprises at least two submodules, employing a bidirectional symmetrical isolated DC-DC converter with two DC ports: a high-voltage side and a low-voltage side. These DC ports serve as energy transmission ports. The high-voltage side DC ports of each submodule are connected in series to the high-voltage DC bus on the high-voltage DC side, enabling high-voltage side power input / output, such as when connected in series with a high-voltage DC grid. The low-voltage side DC ports of each submodule are connected in parallel to the low-voltage DC bus on the low-voltage DC side, enabling low-voltage side power input / output, such as when connected in parallel with an energy storage battery or various low-voltage DC conversion devices. The high-voltage DC side includes the high-voltage DC bus and a connection line on one side of the submodule connected to it, and the high-voltage DC side is fixed as a series connection after the submodule is plugged in and out in either direction. The low-voltage DC side includes the low-voltage DC bus and a connection line on one side of the submodule connected to it, and the low-voltage DC side is fixed as a parallel connection after the submodule is plugged in and out in either direction.

[0020] Because the submodule has bidirectional symmetry, two symmetrical voltage and current equalization feedforward error input ports are respectively set on the primary and secondary sides of the submodule. These input ports are control signal ports, used to receive error correction signals transmitted from the high-voltage side voltage equalization module or the low-voltage side current equalization module. When the submodule is bidirectionally plugged in and out, the side connected to the high-voltage DC side is the voltage equalization feedforward error input port, which is connected to the external high-voltage side voltage equalization module. The side connected to the low-voltage DC side is the current equalization feedforward error input port, which is connected to the external low-voltage side current equalization module. The purpose of setting two input ports on the primary and secondary sides is to ensure signal compatibility during bidirectional plugging and unplugging. When the submodule is plugged in or out in either direction, its primary and secondary sides are swapped. Since the high-voltage and low-voltage DC sides on both sides of the submodule contain the connections between submodules, the high-voltage DC side ensures a series connection between submodules, and the low-voltage DC side ensures a parallel connection between submodules. Therefore, plugging and unplugging in either direction will not affect the series connection on the high-voltage side or the parallel connection on the low-voltage side between submodules. The submodules have symmetrical physical interfaces, and the bidirectional symmetrical topology has the same topology parameters. It supports bidirectional plugging and unplugging in either the forward or reverse direction, and the original and secondary sides can automatically adapt and connect after plugging and unplugging.

[0021] The high-voltage side voltage equalization module and the low-voltage side current equalization module are independent of the sub-modules and the high-voltage and low-voltage DC bus, and control the high-voltage side input voltage equalization and the low-voltage side output current equalization of each sub-module. When the sub-modules are plugged in or out, the primary and secondary sides change. The high-voltage side voltage equalization module is connected to the voltage equalization feedforward error input port of each sub-module, and transmits the voltage error correction signal adjusted by PID to the voltage equalization feedforward error input port of the corresponding sub-module. The low-voltage side current equalization module is connected to the current equalization feedforward error input port of each sub-module, and transmits the current error correction signal adjusted by PID to the current equalization feedforward error input port of the corresponding sub-module, so that the high-voltage side input of each sub-module is the ideal voltage average value, and the low-voltage side output is the ideal current average value.

[0022] The voltage and current equalization method does not require additional communication between the sub-modules, greatly simplifies the control architecture, and improves the reliability of the system.

[0023] The sub-module number monitoring module includes an accumulator and a sensor for monitoring the sub-module insertion state. The sensor is installed at the sub-module slot of the system case, and is in communication connection with the accumulator. The system case serves as a physical carrier and an electrical integration platform for the sub-modules. A plurality of pluggable sub-module slots are arranged in the system case, and the sensor for monitoring the sub-module insertion state is arranged in the slot to monitor the sub-module plugging state. When the sub-module is inserted, the sensor feeds back a 1 signal or a 0 signal to the accumulator when the sub-module is cut out. The accumulator accumulates the signals to generate the actual number n of sub-modules, which is transmitted to the high-voltage side voltage equalization module and the low-voltage side current equalization module in real time, and is used to dynamically adjust the ideal voltage average value input by the sub-module and the ideal current average value output by the sub-module.

[0024] When the output power parameter changes, the sub-modules need to be switched. The sub-module monitoring module can automatically monitor the number n of sub-modules, so that the ideal voltage average value input by each sub-module and the ideal current average value output by each sub-module change in real time with the actual number of sub-modules. The high-voltage side voltage equalization module and the low-voltage side current equalization module can automatically match the number of sub-modules actually put into operation to realize high-voltage side series voltage equalization and low-voltage side parallel current equalization. Therefore, the operation of switching or bidirectional plugging of the sub-modules does not affect the functions of the high-voltage side voltage equalization module and the low-voltage side current equalization module.

[0025] The application realizes bidirectional plug-in of sub-modules under direct-direct conversion, greatly simplifies the process of bidirectional direct current energy transmission and realizes automatic voltage sharing and current sharing while plug and play: after the sub-modules are inserted, the voltage sharing and current sharing modules on the high-voltage side and the low-voltage side can automatically share the voltage and current, and the voltage sharing and current sharing modules can match the characteristics of bidirectional plug-in of the sub-modules. Combined with the power management method of on-demand switching, the system always works in the high-efficiency area, reduces the working loss of each sub-module, realizes high efficiency and high reliability. Moreover, the modular design of the application allows flexible configuration of system power, and the faulty sub-module can be replaced online without affecting the overall operation of the system, realizing extremely high scalability and maintainability.

[0026] The management method of the modular bidirectional plug-in DC-DC topology combination system comprises the following steps: (1) Assemble the modular bidirectional plug-in DC-DC topology combination system; the modular bidirectional plug-in DC-DC topology combination system comprises a system case, which serves as a physical carrier and an electrical integrated platform of sub-modules, and is provided with a plurality of pluggable sub-module slots and a sub-module quantity monitoring module inside; the sub-module quantity monitoring module comprises an accumulator and a sensor for monitoring the access state of the sub-module inside the slot; when the sub-module is inserted, the sensor feeds back a 1 signal and a 0 signal to the accumulator when it is cut out; the accumulator accumulates the signals to generate the actual number n of sub-modules put into use, and the linkage process is as shown in Figure 2 The sub-module adopts a bidirectional symmetric isolated DC-DC converter, and the topology parameters of the operation are consistent to ensure the similarity of the operation of the sub-module after bidirectional plug-in. The high-voltage side direct current port of the sub-module is connected in series to a high-voltage direct current bus on the high-voltage direct current side, and the low-voltage side direct current port is connected in parallel to a low-voltage direct current bus on the low-voltage direct current side; the high-voltage side voltage sharing feedforward error input port of the sub-module is connected with an external high-voltage side voltage sharing module, and the low-voltage side current sharing feedforward error input port is connected with an external low-voltage side current sharing module.

[0027] (2) When switching according to the power requirement, the sub-module quantity monitoring module monitors the number of sub-modules put into use in real time and feeds it back to the high-voltage side voltage sharing module and the low-voltage side current sharing module; The high-voltage side voltage sharing module collects the input voltage signals of the high-voltage side direct current ports of each sub-module in real time U r / s(1…n) , wherein U r / s1 represents the input voltage of the sub-module 1, U r / sn represents the input voltage of the sub-module n, and the like, and is compared with the ideal voltage average value U ref / n, wherein U refThe total ideal voltage value of all sub-modules on the high-voltage side is set, and n is the number of sub-modules; the difference between the two is output as the voltage error correction signal of each sub-module after PID adjustment U r / s(1…n) wherein Δ U r / s1 represents the voltage error correction signal of sub-module 1, Δ U r / sn represents the voltage error correction signal of sub-module n, and the like, which are received by the voltage equalization feedforward error input port of the corresponding sub-module on the high-voltage side; the sub-module continuously adjusts the input voltage on the high-voltage side according to the feedback voltage error correction signal, so that the adjusted input voltage on the high-voltage side of the single sub-module is the average value of the ideal voltage U ref / n, so as to realize the voltage equalization of each sub-module on the high-voltage side; as shown in Figure 3 (a); The low-voltage side current equalization module collects the output current signals of each sub-module on the low-voltage side in real time I r / s(1…n) wherein, I r / s1 represents the output current of sub-module 1, I r / sn represents the output current of sub-module n, and is compared with the average value of the ideal current of the sub-module I ref / n, wherein I ref The total ideal current value of all sub-modules on the low-voltage side is set, and n is the number of sub-modules; the difference between the two is output as the current error correction signal of each sub-module after PID adjustment I r / s(1…n) wherein Δ I r / s1 represents the current error correction signal of sub-module 1, Δ I r / sn represents the current error correction signal of sub-module n, and the like, which are received by the current equalization feedforward error input port of the corresponding sub-module on the low-voltage side; the sub-module continuously corrects the output low-voltage side current error according to the feedback current error correction signal, so that the adjusted output current on the low-voltage side of the single sub-module is the average value of the ideal current I ref / n, so as to realize the current equalization of each sub-module on the low-voltage side; as shown in Figure 3 (b).

[0028] To adapt to the input and output power demand, the number of sub-modules put into operation changes, since the sub-module number monitoring module can obtain the actual number of sub-modules put into operation n in real time through an accumulator, the set ideal voltage and current values change in real time with n, therefore the high-voltage side voltage equalization module and the low-voltage side current equalization module can automatically match the actual number of sub-modules put into operation, without affecting the input of the high-voltage side port voltage and current feedforward error signals, realizing the equal division of the ideal high-voltage side total voltage U ref and the ideal low-voltage side total current I ref .

[0029] In order to further verify the method of the application, the high-voltage side total voltage is 650V, the low-voltage side total current is 90A, and a three-sub-module combined topology structure is adopted, and the experimental results are shown in Figs. Figure 4 、 5 . Figure 4 In Fig. , three waveforms sequentially represent the actual output current waveform diagrams of sub-modules 1-3, and it can be seen from the figure that the three waveforms are consistent, realizing the equal division of the ideal output current. Figure 5 In Fig. , three waveforms sequentially represent the actual input voltage waveform diagrams of sub-modules 1-3, and it can be seen from the figure that the voltage of each sub-module is kept at 217x(1±1%)V after stabilization, and the output error is kept within ±1%, realizing the equal division of the ideal input voltage. The experiment shows that, whether the input voltage of the sub-module or the output current, after passing through the high-voltage side voltage equalization module and the low-voltage side current equalization module, the input voltage and the output current of the three sub-modules can realize the equal division of the ideal input voltage U ref and the ideal output current I ref . The method of the application can ensure the high-voltage side input voltage equalization and the low-voltage side output current equalization of each sub-module in the system starting dynamic process and the steady-state working process, and the control error is ≤1%.

[0030] The application can overcome the problems of low power conversion efficiency and unbalanced module utilization, and can solve the problems of high cost and high loss of the traditional bidirectional symmetric isolation type DC-DC converter charge-discharge circuit, and enhance the flexibility and reliability of practical applications such as electric vehicle charging piles and photovoltaic storage and charging integrated power stations.

Claims

1. A modular bidirectional pluggable DC-DC topology combination system, characterized in that, It includes several structurally identical sub-modules, as well as a high-voltage side equalization module, a low-voltage side current equalization module, and a sub-module quantity monitoring module connected to the sub-modules; The submodule adopts a bidirectional symmetrical isolated DC-DC converter with symmetrical physical interfaces that support bidirectional plug-in / plug-out operations. Each submodule has two DC ports: a high-voltage side and a low-voltage side. The high-voltage side DC port of each submodule is connected in series to the high-voltage DC bus, and the low-voltage side DC port is connected in parallel to the low-voltage DC bus. Each submodule has two symmetrically arranged voltage and current sharing feedforward error input ports on its primary and secondary sides. When the submodule is bidirectionally plugged in / out, the high-voltage side becomes the voltage sharing feedforward error input port, and the low-voltage side becomes the current sharing feedforward error input port. The voltage sharing feedforward error input port is connected to the high-voltage side voltage sharing module, and the current sharing feedforward error input port is connected to the low-voltage side current sharing module. The high-voltage side voltage equalization module inputs the voltage error correction signal of each sub-module into the voltage equalization feedforward error input port of the corresponding sub-module based on the number of sub-modules in use, to achieve series voltage equalization of the high-voltage side input voltage of the sub-modules; the low-voltage side current equalization module inputs the current error correction signal of each sub-module into the current equalization feedforward error input port of the corresponding sub-module based on the number of sub-modules in use, to achieve parallel current equalization of the low-voltage side output current of the sub-modules. The submodule quantity monitoring module is used to monitor the number of submodules put into use in real time and feed it back to the high-pressure side equalization module and the low-pressure side current equalization module.

2. The modular bidirectional pluggable DC-DC topology combination system according to claim 1, characterized in that, The submodule has at least two components.

3. The modular bidirectional pluggable DC-DC topology combination system according to claim 1, characterized in that, The high-voltage DC bus includes a high-voltage DC power grid, and the low-voltage DC bus includes a low-voltage charging and discharging device.

4. A modular bidirectional pluggable DC-DC topology combination system according to claim 1, characterized in that, The submodule quantity monitoring module includes an accumulator and sensors that monitor the access status of submodules.

5. A modular bidirectional pluggable DC-DC topology combination system according to claim 1, characterized in that, The high-voltage side voltage equalization module inputs the voltage error correction signal of each submodule to the voltage equalization feedforward error input port of the corresponding submodule to achieve series voltage equalization of the high-voltage side input voltage of the submodules. This includes the high-voltage side voltage equalization module acquiring the input voltage signal of the DC port of the high-voltage side of each submodule in real time and comparing it with the ideal average voltage of the submodule. The difference obtained is adjusted by PID and output as the voltage error correction signal of each submodule. This signal is received by the corresponding high-voltage side voltage equalization feedforward error input port of the submodule. The submodule continuously adjusts the high-voltage side input voltage according to the feedback voltage error correction signal, so that the adjusted high-voltage side input voltage of a single submodule is the ideal average voltage, thereby achieving voltage equalization of the high-voltage side input voltage of each submodule.

6. A modular bidirectional pluggable DC-DC topology combination system according to claim 1, characterized in that, The low-voltage side current sharing module inputs the current error correction signal of each submodule into the current sharing feedforward error input port of the corresponding submodule to realize parallel current sharing of the low-voltage side output current of the submodules. This includes the low-voltage side current sharing module acquiring the output current signal of the DC port of the low-voltage side of each submodule in real time and comparing it with the ideal current average value of the submodule. The difference obtained is adjusted by PID and output as the current error correction signal of each submodule, which is received by the corresponding low-voltage side current sharing feedforward error input port of the submodule. Each submodule continuously adjusts the low-voltage side output current according to the feedback current error correction signal, so that the low-voltage side output current of a single submodule after adjustment is the ideal current average value, thereby realizing the current sharing of the low-voltage side output current of each submodule.

7. A management method for a modular bidirectional pluggable DC-DC topology combination system according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Based on the different output power parameters, the sub-modules are switched on and off according to the input power characteristics and output power requirements. The sub-module quantity monitoring module monitors the number of sub-modules in use in real time and feeds it back to the high-voltage side equalization module and the low-voltage side current equalization module. (2) The high-voltage side voltage equalization module and the low-voltage side current equalization module respectively collect the input voltage of the high-voltage side port and the output current of the low-voltage side port of each sub-module. Based on the number of sub-modules in use, they are compared with the average ideal voltage and the average ideal current of the sub-modules to obtain two sets of feedforward error correction signals, which are then transmitted to the voltage equalization feedforward error input port and the current equalization feedforward error input port of each sub-module respectively. (3) The submodule continuously adjusts the high-voltage side input voltage and low-voltage side output current according to the feedback error correction signal, so as to realize the equalization of high-voltage side input voltage and low-voltage side output current after bidirectional plugging and unplugging.

8. The management method for a modular bidirectional pluggable DC-DC topology combination system according to claim 7, characterized in that, The submodule quantity monitoring module monitors the number of submodules put into use in real time. This includes a sensor that feeds back a 1 signal when a submodule is inserted and a 0 signal when it is cut off. The accumulator accumulates the signals to generate the actual number of submodules put into use.

9. The management method for a modular bidirectional pluggable DC-DC topology combination system according to claim 7, characterized in that, The high-voltage side voltage equalization module collects the input voltage signals from the DC ports of the high-voltage side of each submodule. ， The voltage error is compared with the ideal average voltage. After PID regulation, the voltage error correction signal of each submodule is output. Finally, the voltage equalization feedforward error port of each submodule in use receives the voltage error correction signal and continuously corrects the error of the high voltage side input voltage of each submodule, so that the high voltage side input voltage of each submodule reaches the ideal average voltage.

10. The management method for a modular bidirectional pluggable DC-DC topology combination system according to claim 7, characterized in that, The low-voltage side current sharing module collects the output current signal of the DC port of the low-voltage side of each submodule and compares it with the ideal current average value. After PID regulation, it outputs the current error correction signal of each submodule. Finally, the current error correction signal is received by the current sharing feedforward error input port of each submodule in use, and the low-voltage side current error of each submodule output is continuously corrected so that the low-voltage side current output of each submodule reaches the ideal current average value.

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