Reconfigurable series-parallel connection network type converter with strong overcurrent capability and construction method of reconfigurable series-parallel connection network type converter

Abstract

The invention provides a reconfigurable series-parallel connection network type converter with high overcurrent capacity and a construction method, and belongs to the technical field of power electronic directional power converters. Comprising the following steps of: respectively connecting two corresponding ports of two asymmetric half-bridge modules, symmetric half-bridge modules or H-bridge modules through two bridge type bidirectional switches or reverse series bidirectional switches, and connecting a group of two non-corresponding ports of the modules through a third bridge type bidirectional switch or reverse series bidirectional switch; according to the converter example, two corresponding ports of two H-bridge modules are connected through two bridge type bidirectional switches respectively, and a group of two non-corresponding ports of the two H-bridge modules are connected through a third bridge type bidirectional switch; on the basis that the number of modules is not increased, the overcurrent capacity of the grid-forming type converter is remarkably improved, and the saturation problem of magnetic elements such as a power semiconductor device and a filter inductor is avoided; the system is modularized, simple in structure, malleable and easy to standardize.

Description

Technical Field

[0001] The invention belongs to the technical field of power converters in the power electronics direction, and particularly relates to a reconfigurable series-parallel grid-forming converter with strong overcurrent capacity and a construction method thereof. Background Technique

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] Grid-connected converters are required in applications such as photovoltaic power generation, wind power generation, grid-connected energy storage, electric vehicle chargers / pile chargers, high-voltage AC / DC power transmission, power quality management, and microgrids, and they undertake the task of AC / DC power conversion. According to the grid support function, grid-connected converters can be divided into two categories: grid-following converters and grid-forming converters. Among them, grid-following converters are equivalent to controlled current sources, and grid-forming converters are equivalent to controlled voltage sources. The latter has advantages such as seamless grid-connected / off-grid switching, good weak grid stability, programmable inertia and damping, and automatic multi-machine synchronization, and plays a crucial role in modern power grids.

[0004] Strong overcurrent is one of the key challenges still faced by grid-forming converters. According to the requirements of standards and grid guidelines, grid-forming converters need to bear an overcurrent of about 3 times for 10 s, while the overcurrent capacity of power semiconductor devices and magnetic components does not exceed 1.5 times the rated value, and there is an irreconcilable conflict between the two. To improve the overcurrent capacity, existing grid-forming converter products are usually composed of several converters connected in parallel, which have disadvantages such as high cost, large volume, heavy weight, low efficiency, and complex control.

[0005] In addition, existing methods for improving the overcurrent capacity of grid-forming converters mostly target power semiconductor devices, cannot solve the problem of saturation of magnetic components such as filter inductors, and the regulation cost of related drive circuits is high and the design is complex, making it difficult to be universal and standardized. Summary of the Invention To solve the above problems, the present invention proposes a reconfigurable series-parallel grid-forming converter with strong overcurrent capacity and a construction method thereof. The present invention uses bidirectional switches to connect modules according to certain rules, so that the modules can be reconfigured into series or parallel operating states in real time according to grid requirements. Compared with traditional grid-forming converters, the present invention significantly improves the overcurrent capacity of grid-forming converters without increasing the number of modules, and has a simple structure and ductility.

[0006] According to some embodiments, the present invention adopts the following technical solutions: In the first aspect, the present invention provides a construction method of a reconfigurable series-parallel grid-forming converter with strong overcurrent capacity.

[0007] The construction method of a reconfigurable series-parallel grid-forming converter with strong overcurrent capacity includes: Connect the corresponding two ends of at least two modules together through a bidirectional switch respectively, and connect a group of non-corresponding two ends of these two modules together through another bidirectional switch, as shown in Figure 4 .

[0008] In a second aspect, the present invention provides an example of a reconfigurable series-parallel grid-connected converter with strong overcurrent capacity.

[0009] The reconfigurable series-parallel grid-connected converter with strong overcurrent capacity adopts the construction method of the reconfigurable series-parallel grid-connected converter described in the first aspect, and connects at least two Figure 2a as shown in the bidirectional switches to connect at least two Figure 1c as shown in the H-bridge modules to form Figure 6 the reconfigurable series-parallel grid-connected converter shown; including: at least three bidirectional switches, at least two H-bridge modules, at least two output terminals; Among them, the first port of the first H-bridge module is connected to the first port of the second H-bridge module through the first bidirectional switch, the second port of the first H-bridge module is connected to the second port of the second H-bridge module through the second bidirectional switch, and the second port of the first H-bridge module is connected to the first port of the second H-bridge module through the third bidirectional switch; The first port of the first H-bridge module is the first output port of the grid-connected converter, and the second port of the second H-bridge module is the second output port of the grid-connected converter.

[0010] Compared with the prior art, the beneficial effects of the present invention are: Compared with the traditional grid-connected converter, the present invention can reconfigure the converter into a series or parallel operation state of the modules in real time as needed; significantly improve the overcurrent capacity of the converter without increasing the number of modules; the voltage can be evenly distributed among the modules and more levels can be output in the series operation state; the current can be evenly distributed among the modules in the parallel operation state, avoiding the saturation of power semiconductor devices and magnetic components (including filter inductors); the converter has a simple structure and is easy to standardize. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0012] Figure 1a is a structural diagram of a traditional asymmetric half-bridge module; Figure 1b is a structural diagram of a traditional symmetric half-bridge module; Figure 1c is a structural diagram of a traditional H-bridge module; Figure 2aIt is a structural diagram of a traditional bridge-type bidirectional switch; Figure 2b It is a structural diagram of a traditional anti-series bidirectional switch; Figure 3a It is a structural diagram of a traditional cascaded network-forming converter; Figure 3b It is a structural diagram of a traditional parallel network-forming converter; Figure 4 It is a structural diagram of a construction method of a reconfigurable series-parallel network-forming converter implemented in the present invention; Figure 5 It is a structural diagram of a three-phase construction method of a reconfigurable series-parallel network-forming converter implemented in the present invention; Figure 6 It is a structural diagram of an example of a reconfigurable series-parallel network-forming converter implemented in the present invention; Figure 7a It is a schematic diagram of the series operating state of an example of a reconfigurable series-parallel network-forming converter implemented in the present invention; Figure 7b It is a schematic diagram of the parallel operating state of an example of a reconfigurable series-parallel network-forming converter implemented in the present invention; Figure 8a It is the load voltage of an example of a reconfigurable series-parallel network-forming converter implemented in the present invention under the series operating state v load and load current i load (upper left), module current i ac1 / i ac2 (upper right), bidirectional switch voltage v s1 / v s2 / v s3 (lower left), bidirectional switch current i s1 / i s2 / i s3 (lower right) simulation waveform diagram.

[0013] Figure 8b It is the load voltage of an example of a reconfigurable series-parallel network-forming converter implemented in the present invention under the parallel operating state v load and load current i load (upper left), module current i ac1 / i ac2 (upper right), bidirectional switch voltage vs1 / v s2 / v s3 (lower left), bidirectional switch current i s1 / i s2 / i s3 The simulation waveform diagrams of (lower right).

[0014] Table 1 is the simulation system and control parameter table of the reconfigurable series-parallel networked converter example implemented in the present invention. Specific implementation manners

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0016] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further descriptions of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0017] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary implementation manners according to the present invention. As used herein, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should be understood that when the term "comprising" is used in this specification, it indicates the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0018] In the present invention, terms such as "connected" and "connected" should be understood in a broad sense, which may mean a fixed connection, an integral connection or a detachable connection; it may be directly connected or indirectly connected through an intermediate medium. For those related scientific research or technical personnel in the field, the specific meanings of the above terms in the present invention can be determined according to specific circumstances and should not be construed as a limitation to the present invention.

[0019] Embodiment 1 This embodiment provides a construction method of a reconfigurable series-parallel networked converter with strong overcurrent capacity.

[0020] A construction method of a reconfigurable series-parallel networked converter with strong overcurrent capacity, comprising: Connect the corresponding first ports (418 and 417) of at least two modules 411 (specifically, the asymmetric half-bridge module 101, or the symmetric half-bridge module 102, or the H-bridge module 103) and the module 412 (specifically, the asymmetric half-bridge module 101, or the symmetric half-bridge module 102, or the H-bridge module 103) together through a first bidirectional switch 413 (specifically, the bridge-type bidirectional switch 201 or the anti-series bidirectional switch 202); connect the corresponding second ports (416 and 419) of the module 411 (specifically, the asymmetric half-bridge module 101, or the symmetric half-bridge module 102, or the H-bridge module 103) and the module 412 (specifically, the asymmetric half-bridge module 101, or the symmetric half-bridge module 102, or the H-bridge module 103) together through a second bidirectional switch 415 (specifically, the bridge-type bidirectional switch 201 or the anti-series bidirectional switch 202); connect the second port 416 of the module 411 (specifically, the asymmetric half-bridge module 101, or the symmetric half-bridge module 102, or the H-bridge module 103) and the first port 417 of the module 412 (specifically, the asymmetric half-bridge module 101, or the symmetric half-bridge module 102, or the H-bridge module 103) together through a third bidirectional switch 414 (specifically, the bridge-type bidirectional switch 201 or the anti-series bidirectional switch 202). After the connection is completed, the port 418 is the first output port of the reconfigurable series-parallel network converter, and the port 419 is the second output port of the reconfigurable series-parallel network converter, as Figure 4 shown.

[0021] Optionally, the module 411 and the module 412 can be ( Figure 1a the asymmetric half-bridge module 101 shown), ( Figure 1b the symmetric half-bridge module 102 shown), or ( Figure 1c the H-bridge module 103 shown).

[0022] Optionally, the first bidirectional switch 413, the third bidirectional switch 414, and the second bidirectional switch 415 can be ( Figure 2a the bridge-type bidirectional switch 201 shown) or ( Figure 2b the anti-series bidirectional switch 202 shown).

[0023] Among them, as Figure 1aAs shown, the asymmetric half-bridge module 101 includes at least two switches (the first switch 111 and the second switch 112), at least one energy storage element 113 and at least one filter inductor 114 or filter inductor 115. The first port of the first switch 111 is connected to one port of the energy storage element 113 (the connection point is 116), the other port of the energy storage element 113 is connected to the second port of the second switch 112 (the connection point is 117), the first port of the second switch 112 is connected to the second port of the first switch 111 (the connection point is 118), the connection point 118 of the two switches is the second port of the filter inductor 114, the first port of the filter inductor 114 is the first output port 119 of the module, the connection point 117 of the energy storage element and the second switch is the second port of the filter inductor 113, the first port of the filter inductor 113 is the second output port 1110 of the module, and the filter inductor 114 and the filter inductor 113 can work simultaneously or one of them can be short-circuited.

[0024] Among them, as Figure 1b As shown, the symmetric half-bridge module 102 includes at least two switches (the first switch 121 and the second switch 122), at least two energy storage elements (the first energy storage element 123 and the second energy storage element 124) and at least one filter inductor 125 or filter inductor 126. The first port of the first switch 121 is connected to the first port of the first energy storage element 123 (the connection point is 127), the second port of the second switch 122 is connected to the second port of the second energy storage element 124 (the connection point is 128), the second port of the first switch 121 is connected to the first port of the second switch 122 (the connection point is 129), the second port of the first energy storage element 123 is connected to the first port of the second energy storage element 124 (the connection point is 1210), the connection point 129 of the two switches is the second port of the filter inductor 125, the first port of the filter inductor 125 is the first output port 1211 of the module, the connection point 1210 of the two energy storage elements is the second port of the filter inductor 126, the first port of the filter inductor 126 is the second output port 1212 of the module, and the filter inductor 125 and the filter inductor 126 can work simultaneously or one of them can be short-circuited.

[0025] Among them, as Figure 1cAs shown, the H-bridge module 103 includes at least four switches (the first switch 131, the second switch 132, the third switch 133, and the fourth switch 134), at least one energy storage element 135, and at least one filter inductor 136 or filter inductor 137. The first port of the first switch 131 is connected to the first port of the energy storage element 135 and the first port of the third switch 133 (the connection point is 138). The second port of the second switch 132 is connected to the second port of the energy storage element 135 and the second port of the fourth switch 134 (the connection point is 139). The second port of the first switch 131 is connected to the first port of the second switch 132 (the connection point is 1310). The second port of the third switch 133 is connected to the first port of the fourth switch 134 (the connection point is 1311). The connection point 1310 of the first switch and the second switch is the second port of the filter inductor 136, and the first port of the filter inductor 136 is the first output port 1312 of the module. The connection point 1311 of the third switch and the fourth switch is the second port of the filter inductor 137, and the first port of the filter inductor 137 is the second output port 1313 of the module. The two filter inductors 136 and 137 can work simultaneously or one of them can be short-circuited.

[0026] Among them, as Figure 2a shown, the bridge-type bidirectional switch 201 includes at least one semiconductor power switch 211 and at least four diodes (the first diode 212, the second diode 213, the third diode 214, and the fourth diode 215). The first port of the semiconductor power switch 211 is connected to the first port of the first diode 212 and the first port of the third diode 214 (the connection point is 216). The second port of the semiconductor power switch 211 is connected to the second port of the second diode 213 and the second port of the fourth diode 215 (the connection point is 217). The second port of the first diode 212 is connected to the first port of the second diode 213 and serves as the first output port 218 of the bridge-type bidirectional switch. The second port of the third diode 214 is connected to the first port of the fourth diode 215 and serves as the second output port 219 of the bridge-type bidirectional switch.

[0027] Among them, as Figure 2b shown, the anti-series bidirectional switch 202 includes at least two switches (the first switch 221 and the second switch 222). The first port of the first switch 221 is connected to the first port of the second switch 222 (the connection point is 223). The second port of the first switch 221 is the first output port 224 of the anti-series bidirectional switch. The second port of the second switch 222 is the second output port 225 of the anti-series bidirectional switch.

[0028] Optionally, the switch can be implemented using IGBT, MOSFET, SiC, or GaN power switch devices.

[0029] Optionally, the energy storage element includes: a capacitor, a supercapacitor, a lithium battery pack, a lead-acid battery pack, or a sodium-sulfur battery pack.

[0030] Embodiment 2 This embodiment provides an example of a reconfigurable series-parallel grid-connected converter with strong overcurrent capacity.

[0031] A reconfigurable series-parallel grid-connected converter with strong overcurrent capacity, which adopts the construction method of the reconfigurable series-parallel grid-connected converter described in Embodiment 1, includes: at least two H-bridge modules 103, at least three bidirectional switches 413, 414, 415 as Figure 6 shown.

[0032] See Appendix Figure 1a , the asymmetric half-bridge module 101 has a total of 3 operating modes, including positive voltage output, zero voltage output, and open circuit mode. Among them, when the first switch 111 or the second switch 112 is turned on, it is the positive voltage and zero voltage output modes respectively; when all switches are turned off, it is the open circuit mode. By controlling and changing the time ratio of different operating modes, the voltages of the output ports 119 and 1110 of the asymmetric half-bridge module can be adjusted.

[0033] See Appendix Figure 1b , the symmetric half-bridge module 102 has a total of 3 operating modes, including positive voltage output, negative voltage output, and open circuit mode. Among them, when the first switch 121 or the second switch 122 is turned on, it is the positive voltage and negative voltage output modes respectively; when all switches are turned off, it is the open circuit mode. By controlling and changing the time ratio of different operating modes, the voltages of the output ports 1211 and 1212 of the symmetric half-bridge module can be adjusted.

[0034] See Appendix Figure 1c , the H-bridge module 103 has a total of 4 operating modes, including positive voltage output, negative voltage output, zero voltage output, and open circuit mode. Among them, when two diagonal switches 131, 134 or 132, 133 are turned on, they are the positive voltage and negative voltage output modes respectively; when two upper switches 131, 133 or two lower switches 132, 134 are turned on, it is the zero voltage output mode; when all switches are turned off, it is the open circuit mode. By controlling and changing the time ratio of different operating modes, the voltages of the output ports 1312 and 1313 of the H-bridge module can be adjusted.

[0035] See Appendix Figure 2a , the bridge-type bidirectional switch 201 has a total of 2 operating modes, including conduction mode and open circuit mode. Among them, when the switch 211 is turned on, it corresponds to the conduction mode of the bridge-type bidirectional switch 201, and when the switch 211 is turned off, it corresponds to the open circuit mode of the bridge-type bidirectional switch 201.

[0036] See Appendix Figure 2b, the anti-series-connected bidirectional switch 202 has a total of two operating modes, including a conduction mode and an open-circuit mode. Among them, when both the first switch 221 and the second switch 222 are conducting, it corresponds to the conduction mode of the anti-series-connected bidirectional switch 202, and when both the first switch 221 and the second switch 222 are turned off, it corresponds to the open-circuit mode of the anti-series-connected bidirectional switch 202.

[0037] See Appendix Figure 3a , multiple modules 311 (asymmetric half-bridge module 101 or symmetric half-bridge module 102 or H-bridge module 103) can be connected in series end to end to form a traditional module series-connected network-type converter 301.

[0038] See Appendix Figure 3a , multiple modules 321 (asymmetric half-bridge module 101 or symmetric half-bridge module 102 or H-bridge module 103) can be connected in parallel at both ends to form a traditional module parallel-connected network-type converter 302.

[0039] See Appendix Figure 4 , a single-phase reconfigurable series-parallel network-type converter can be constructed based on the above modules and bidirectional switches according to the construction method described in Embodiment 1.

[0040] See Appendix Figure 5 , it is possible to Figure 4 connect a set of corresponding ends of each of the three reconfigurable series-parallel network-type converters shown, and use the unconnected ports as output terminals, thereby constructing a three-phase reconfigurable series-parallel network-type converter.

[0041] See Appendix Figure 6 , replace the two modules 411 and 412 of Figure 4 shown in 401 with an H-bridge module 103, and replace the first bidirectional switch 413, the third bidirectional switch 414, and the second bidirectional switch 415 with a bidirectional switch 201 to obtain an example of a reconfigurable series-parallel network-type converter.

[0042] See Appendix Figure 7a , when the first bidirectional switch 413 and the second bidirectional switch 415 are turned off and the bidirectional switch 414 is conducting, the reconfigurable series-parallel network-type converter can achieve module series operation.

[0043] See Appendix Figure 7b , when the first bidirectional switch 413 and the second bidirectional switch 415 are conducting and the bidirectional switch 414 is turned off, the reconfigurable series-parallel network-type converter can achieve module parallel operation.

[0044] The simulation system and control parameters of the example of the reconfigurable series-parallel network-type converter implemented in the present invention are shown in Table 1.

[0045] Table 1 Simulation System and Control Parameter Table

[0046] See the appendix Figure 8a , which shows the load voltage of the reconfigurable series-parallel network-forming converter example in the series operating state v load and the load current i load (upper left), the module current i ac1 / i ac2 (upper right), the bidirectional switch voltage v s1 / v s2 / v s3 (lower left), the bidirectional switch current i s1 / i s2 / i s3 (lower right); as can be seen Figure 8a , in the series mode, the modules can evenly divide the load voltage, and the turned-off bidirectional switches evenly divide the load voltage, while the turned-on bidirectional switches bear the load current.

[0047] See the appendix Figure 8b , which shows the load voltage of the reconfigurable series-parallel network-forming converter example in the parallel operating state v load and the load current i load (upper left), the module current i ac1 / i ac2 (upper right), the bidirectional switch voltage v s1 / v s2 / v s3 (lower left), the bidirectional switch current i s1 / i s2 / i s3 (lower right); as can be seen Figure 8b , in the parallel mode, the modules can evenly divide the load current, and on the premise of ensuring the current-carrying capacity of the power semiconductor and the filter inductor remains unchanged, the overcurrent capacity of the network-forming converter is increased by at least 2 times. At the same time, the turned-on bidirectional switches evenly divide the load current, and the turned-off bidirectional switches bear the load voltage.

[0048] The present invention provides a method for constructing a reconfigurable series-parallel network-forming converter and an example of a reconfigurable series-parallel network-forming converter, which can be applied to scenarios such as photovoltaic power generation, wind power generation, grid-connected energy storage, electric vehicle chargers / pile chargers, high-voltage AC / DC power transmission, power quality management, and microgrids. Compared with traditional network-forming converters, the present invention significantly improves the overcurrent capacity of the network-forming converter without increasing the number of modules, and the voltage and current can be evenly distributed among the modules as needed, with a simple structure and extensibility.

[0049] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Construction method of a reconfigurable series-parallel networked converter with strong over-current capacity, characterized in that, Comprising: Connecting the first ports corresponding to at least two modules together through a first bidirectional switch; The two modules are a first module and a second module respectively; Connecting the second ports corresponding to the first module and the second module together through a second bidirectional switch; Connecting the second port of the first module and the first port of the second module together through a third bidirectional switch; After the connection is completed, the first port of the first module is the first output port of the reconfigurable series-parallel network-forming converter, and the second port of the second module is the second output port of the reconfigurable series-parallel network-forming converter.

2. The construction method of the reconfigurable series-parallel network type converter according to claim 1, wherein, The first module and the second module can be an asymmetric half-bridge module, a symmetric half-bridge module or a symmetric H-bridge module.

3. The construction method of the reconfigurable series-parallel network type converter according to claim 1, characterized in that, The first bidirectional switch, the second bidirectional switch and the third bidirectional switch can be a bridge-type bidirectional switch or an anti-series-connected bidirectional switch.

4. The method for constructing a reconfigurable series-parallel network type converter according to claim 2, characterized in that, The asymmetric half-bridge module includes at least two switches, at least one energy storage element and at least one filter inductor; The two switches are a first switch and a second switch respectively; the filter inductor is a first filter inductor or a second filter inductor; The first port of the first switch is connected to one port of the energy storage element, the other port of the energy storage element is connected to the second port of the second switch, the first port of the second switch is connected to the second port of the first switch, the connection point of the first switch and the second switch is the second port of the first filter inductor, the first port of the first filter inductor is the first output port of the module, the connection point of the energy storage element and the second switch is the second port of the second filter inductor, the first port of the second filter inductor is the second output port of the module, and the two filter inductors can work simultaneously or short-circuit one of them.

5. The method for constructing a reconfigurable series-parallel network type converter according to claim 2, characterized in that The symmetric half-bridge module includes at least two switches, at least two energy storage elements and at least one filter inductor; The two switches are a first switch and a second switch respectively; the two energy storage elements are a first energy storage element and a second energy storage element respectively; the filter inductor is a first filter inductor or a second filter inductor; The first port of the first switch is connected to the first port of the first energy storage element, the second port of the second switch is connected to the second port of the second energy storage element, the second port of the first switch is connected to the first port of the second switch, the second port of the first energy storage element is connected to the first port of the second energy storage element, the connection point of the two switches is the second port of the first filter inductor, the first port of the first filter inductor is the first output port of the module, the connection point of the two energy storage elements is the second port of the second filter inductor, the first port of the second filter inductor is the second output port of the module, and the two filter inductors can work simultaneously or short-circuit one of them.

6. The method for constructing a reconfigurable series-parallel network type converter according to claim 2, wherein, The H-bridge module includes at least four switches, at least one energy storage element and at least one filter inductor; The four switches are a first switch, a second switch, a third switch and a fourth switch respectively; the filter inductor is a first filter inductor or a second filter inductor; The first port of the first switch is connected to the first port of the energy storage element and the first port of the third switch. The second port of the second switch is connected to the second port of the energy storage element and the second port of the fourth switch. The second port of the first switch is connected to the first port of the second switch. The second port of the third switch is connected to the first port of the fourth switch. The connection point of the first switch and the second switch is the second port of the first filter inductor. The first port of the first filter inductor is the first output port of the module. The connection point of the third switch and the fourth switch is the second port of the second filter inductor. The first port of the second filter inductor is the second output port of the module. The two filter inductors can work simultaneously or one of them can be short-circuited.

7. The method for constructing a reconfigurable series-parallel network type converter according to claim 3, wherein The bridge-type bidirectional switch includes at least one semiconductor power switch and at least four diodes; The four diodes are respectively the first diode, the second diode, the third diode, and the fourth diode; The first port of the semiconductor power switch is connected to the first port of the first diode and the first port of the third diode. The second port of the semiconductor power switch is connected to the second port of the second diode and the second port of the fourth diode. The second port of the first diode is connected to the first port of the second diode and serves as the first output port of the bridge-type bidirectional switch. The second port of the third diode is connected to the first port of the fourth diode and serves as the second output port of the bridge-type bidirectional switch.

8. The method for constructing a reconfigurable series-parallel network type converter according to claim 3, wherein The anti-series bidirectional switch includes at least two switches; The two switches are respectively the first switch and the second switch; The first port of the first switch is connected to the first port of the second switch. The second port of the first switch is the first output port of the anti-series bidirectional switch. The second port of the second switch is the second output port of the anti-series bidirectional switch.

9. The construction method of the reconfigurable series-parallel networked converter according to any one of claims 1-8, characterized in that, The switch adopts including: IGBT, MOSFET, SiC or GaN power switch devices.

10. The method for constructing a reconfigurable series-parallel networked converter according to any one of claims 4-6, characterized in that, The described energy storage element adopts including: capacitor, supercapacitor, lithium battery pack, lead-acid battery pack or sodium-sulfur battery pack.

11. The construction method of the reconfigurable series-parallel network type converter according to claim 1, characterized in that, The method is applicable to three-phase applications and can be connected into a star structure through three single-phase converters.

12. A reconfigurable series-parallel networked converter with strong overcurrent capacity, characterized in that, Obtained by using the method for constructing a reconfigurable series-parallel networked converter described in claim 1, including: two H-bridge modules and three bidirectional switches.

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