A variable-ratio configurable combined dc-dc transformer, design method and system

Abstract

The application discloses a variable-ratio configurable combined direct-current transformer, a design method and a system, and comprises the following steps: designing a resonant switch capacitor module according to the high-voltage operation environment requirement of the direct-current transformer; determining the quantity of the resonant switch capacitor modules to be combined, the connection mode and the combination mode according to the variable ratio of the direct-current transformer required by a user; and establishing the direct-current transformer after variable-ratio configuration according to the quantity of the resonant switch capacitor modules to be combined, the connection mode, the combination mode and the resonant switch capacitor module. The application can be flexibly applied to different application scenarios under different user requirements by changing the module quantity, the number of series-connected devices and the combination mode.

Description

Technical Field

[0001] This invention relates to the field of DC transformer turns ratio configuration technology, and in particular to a combined DC transformer with configurable turns ratio, its design method, and system. Background Technology

[0002] Existing renewable energy access methods mainly include three forms: AC aggregation-AC transmission, AC aggregation-DC transmission, and DC aggregation-DC transmission. AC aggregation-AC transmission and AC aggregation-DC transmission are currently the mainstream access methods for renewable energy. However, when large-scale renewable energy is connected to a weak AC power grid using these two methods, it poses a severe challenge to the grid's carrying capacity and stability. Compared to the other two grid connection technologies, DC aggregation-DC transmission technology (i.e., pure DC access technology for renewable energy) only needs to maintain DC voltage stability to achieve overall grid stability. It has a single control objective and a fast response speed, making it a beneficial exploration for solving renewable energy access and realizing a new generation of power systems.

[0003] New energy DC grids often require multiple DC boost stages to transmit renewable energy. While medium- and low-voltage DC transformer technology has seen some research and application, there is still a lack of targeted research for large-scale new energy DC aggregation. On the one hand, DC transformers for large-scale new energy aggregation can only have unidirectional power flow and single-ended voltage control capabilities, and existing topologies are mainly bidirectional, resulting in high costs. On the other hand, large-scale new energy aggregation requires high-voltage output DC voltages of several hundred kilovolts to meet long-distance aggregation needs. Existing topologies are mainly designed for voltage levels of 10kV and below. For voltage levels above several hundred kilovolts, existing topologies have a large number of modules and transformers, and their cost, size, efficiency, and reliability cannot yet meet the requirements for large-scale new energy DC aggregation.

[0004] High-voltage direct current (HVDC) transformers currently lack engineering applications. Existing ISOP, multilevel, and MMC solutions, when directly applied to high-voltage applications, suffer from numerous modules and isolation transformers, resulting in high costs, large size, low efficiency, and low reliability. This not only hinders the widespread application of DC transformers themselves but also severely impedes the promotion and application of new energy DC grid connection systems. Therefore, there is an urgent need to develop new, low-cost, high-power-density, high-efficiency, and high-reliability HVDC transformers. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the aforementioned existing problems, the present invention is proposed.

[0007] Therefore, the present invention provides a combined DC transformer with configurable turns ratio, a design method and a system that can solve the problems mentioned in the background art.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a combined DC transformer with configurable turns ratio, characterized in that it includes at least two interleaved parallel high-voltage conversion modules.

[0009] The interleaved parallel high-voltage conversion module includes at least two high-voltage conversion modules, and the interleaved parallel high-voltage conversion module is composed of at least two high-voltage conversion modules connected in parallel;

[0010] The high-voltage conversion module includes at least two resonant switched capacitor modules, and the high-voltage conversion module is composed of at least two resonant switched capacitor modules connected in series.

[0011] The at least two interleaved parallel high-voltage conversion modules are cascaded to form a DC transformer.

[0012] As a preferred embodiment of the configurable-ratio combined DC transformer described in this invention, the resonant switched capacitor module includes:

[0013] A diode or / and a diode series valve system is referred to as a diode bridge arm, and a thyristor or / and a thyristor series valve system is referred to as a thyristor bridge arm;

[0014] The resonant switched capacitor module consists of a set of thyristor bridge arms containing anti-parallel diode bridge arms, a DC capacitor, and a resonant branch.

[0015] The thyristor bridge arm includes an auxiliary voltage equalization branch. The auxiliary voltage equalization circuit is used for voltage equalization of devices and reliable turn-off of the thyristor bridge arm. The auxiliary voltage equalization circuit consists of at least one capacitor and at least one resistor.

[0016] The resonant branch exchanges energy between the DC capacitor and the input side through an energy transfer path composed of a resonant inductor and a resonant capacitor.

[0017] As a preferred embodiment of the configurable-ratio combined DC transformer described in this invention, the high-voltage conversion module includes:

[0018] The high-voltage conversion module consists of at least two resonant switched capacitor modules and a set of thyristor bridge arms on the input side;

[0019] The DC capacitors of the at least two resonant switched capacitor modules are connected in series with the input side to simultaneously support the output voltage. When the output voltage is n+1 times the input voltage, the high-voltage conversion module composed of the at least two resonant switched capacitor modules and a set of thyristor bridge arms on the input side has a transformation ratio of n+1.

[0020] As a preferred embodiment of the configurable-ratio combined DC transformer described in this invention, it further includes:

[0021] Establish n I Each high-voltage conversion module, and respectively converts the n... I The input side of each high-voltage conversion module is connected in parallel, and the output side is connected in parallel to form a high-voltage conversion module with an interleaved parallel structure.

[0022] When high-voltage converter modules are configured in an interleaved parallel structure, n I The current stress and capacitor voltage ripple in the high-voltage conversion module are reduced compared to the high-voltage conversion module that is not interleaved in parallel.

[0023] Establish n s A high-voltage conversion module with an interleaved parallel structure, and respectively converts the n s The input and output sides of a high-voltage conversion module with an interleaved parallel structure are connected in series to form a high-ratio DC transformer.

[0024] As a preferred embodiment of the configurable-ratio combined DC transformer described in this invention, it further includes:

[0025] Establish n s Each of the aforementioned interleaved parallel high-voltage conversion modules, and respectively converts the n... s The input and output sides of a high-voltage converter module with an interleaved parallel structure are connected in series to perform n... s If the transformation ratio of the high-voltage converter module is n+1, then the transformation ratio of the high-voltage converter modules connected in series is: This constitutes a change ratio The DC transformer, wherein n I and n s Determined by the variation in user demand.

[0026] As a preferred embodiment of the configurable-ratio combined DC transformer described in this invention, the high-voltage conversion module further includes:

[0027] When energy is transferred from the low-voltage side to the high-voltage side, and all even-numbered switches are triggered, the second lower thyristor bridge arm on the input side conducts. At this time, the voltage of the resonant capacitor is less than the voltage of the input capacitor, and the anti-parallel diode of the second right thyristor bridge arm of the resonant switching capacitor module conducts under forward voltage drop. The resonant branch forms a resonant circuit with the input side through the thyristor bridge arm and the diode bridge arm.

[0028] If the resonant capacitor absorbs energy, the voltage rises and the resonant current returns to 0, at which point the thyristor bridge arm naturally turns off.

[0029] As a preferred embodiment of the configurable-ratio combined DC transformer described in this invention, the high-voltage conversion module further includes:

[0030] When energy is transferred from the low-voltage side to the high-voltage side, and the voltage of the resonant capacitor in the resonant branch absorbs energy and rises, the voltage of the resonant capacitor is greater than the voltage of the input capacitor. At this time, the second lower thyristor bridge arm is in the reverse recovery stage. Both the diode bridge arm and the thyristor bridge arm have voltage equalization branches. The resonant branch forms a reverse resonant circuit with the input side through the voltage equalization branch.

[0031] When the circuit parameters meet the overdamping condition, the reverse resonance monotonically decays, and the reverse resonance current passes through the voltage equalization branch of the reverse parallel diode of the second lower thyristor bridge arm. At this time, a constant reverse voltage is applied to the second lower thyristor bridge arm.

[0032] When the time for applying the reverse voltage is greater than the turn-off time of the second lower thyristor bridge arm, the second lower thyristor bridge arm is reliably turned off.

[0033] As a preferred embodiment of the configurable-ratio combined DC transformer described in this invention, the high-voltage conversion module further includes:

[0034] When energy is transferred from the low-voltage side to the high-voltage side, and all the odd-numbered switches are triggered, the first lower thyristor bridge arm on the input side is turned on. At this time, the voltage of the resonant capacitor is less than the voltage of the input capacitor. The anti-parallel diode of the first left thyristor bridge arm of the resonant switching capacitor module is turned on by the forward voltage drop. The resonant branch forms a resonant circuit through the thyristor bridge arm, the diode bridge arm and the DC capacitor.

[0035] If the resonant capacitor releases energy, the voltage drops, the resonant current returns to 0, and the thyristor bridge arm naturally turns off.

[0036] As a preferred embodiment of the configurable-ratio combined DC transformer described in this invention, the high-voltage conversion module further includes:

[0037] When energy is transferred from the low-voltage side to the high-voltage side, and the voltage of the resonant capacitor in the resonant branch drops as it releases energy, the voltage of the resonant capacitor is less than the voltage of the DC capacitor. At this time, the first upper thyristor bridge arm on the input side is in the reverse recovery phase. Both the diode bridge arm and the thyristor bridge arm have voltage equalization branches. The resonant branch forms a reverse resonant circuit with the DC capacitor through the voltage equalization branch and the anti-parallel diode.

[0038] When the circuit parameters meet the overdamping condition, the reverse resonance monotonically decays, and the reverse resonance current passes through the voltage equalization branch of the reverse parallel diode of the first upper thyristor bridge arm. At this time, a constant reverse voltage is applied to the first upper thyristor bridge arm.

[0039] When the time for applying the reverse voltage is greater than the turn-off time of the first upper thyristor bridge arm, the first upper thyristor bridge arm is reliably turned off.

[0040] As a preferred embodiment of the configurable DC transformer described in this invention, the high-voltage conversion module further includes, when transmitting energy from the high-voltage side to the low-voltage side, switching the switch control sequence, and the remaining working principle is the same as that for transmitting energy from the low-voltage side to the high-voltage side.

[0041] As a preferred embodiment of the configurable-ratio combined DC transformer described in this invention, it further includes:

[0042] When a set of thyristors containing anti-parallel diodes and / or thyristor series valves in a resonant switched capacitor module is replaced by a set of valves containing anti-diodes and / or diodes in series, the DC transformer becomes unidirectional.

[0043] A design method for a combined DC transformer with configurable turns ratio, characterized in that it includes:

[0044] Design a resonant switched capacitor module based on the requirements of high-voltage operation environment of DC transformers;

[0045] Based on the DC transformer turns ratio required by the user, determine the number, connection method, and combination method of the resonant switched capacitor modules to be combined.

[0046] The DC transformer is configured with turns ratio based on the number, connection method, and combination method of the resonant switched capacitor modules to be combined.

[0047] A combined DC transformer system with configurable turns ratio, characterized in that it includes a resonant switched capacitor design module, a parameter determination module, and a turns ratio configuration module.

[0048] A resonant switched capacitor design module is used to design a resonant switched capacitor module according to the requirements of the high-voltage operating environment of a DC transformer.

[0049] The parameter determination module is used to determine the number, connection method, and combination method of the resonant switched capacitor modules to be combined according to the DC transformer turns ratio required by the user.

[0050] A turns ratio configuration module is used to establish a DC transformer with a turns ratio configuration based on the number, connection method, and combination method of the resonant switched capacitor modules to be combined and the resonant switched capacitor modules.

[0051] A computer device includes a memory and a processor, the memory storing a computer program, characterized in that the processor executes the computer program to implement the steps of the method described above.

[0052] A computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the steps of the method described above.

[0053] The beneficial effects of this invention are as follows: This invention proposes a combined DC transformer with configurable turns ratio, a design method, and a system. The DC transformer has a simple structure, achieving self-balancing only through the resonance principle. It does not require a large number of submodules to achieve high-voltage applications; only high-capacity semi-controlled devices or their series valves are needed. Using semi-controlled devices instead of fully controlled devices results in lower cost and lower losses. Based on the flexible series-parallel combination capability between modules, this DC transformer topology can achieve high turns ratio and high power transmission capability under high voltage. The staggered parallel structure reduces the stress on the devices. The series structure combined with cascaded configurations allows for non-linear increases in turns ratio, significantly reducing the number of modules. This invention can be flexibly adapted to different application scenarios with varying user needs by changing the number of modules, the number of devices connected in series, and the combination method. Attached Figure Description

[0054] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0055] Figure 1 A flowchart illustrating a design method and system for a combined DC transformer with configurable turns ratio, as provided in one embodiment of the present invention.

[0056] Figure 2 A flowchart illustrating the construction of a DC transformer with configurable turns ratio, design method, and system, as provided in one embodiment of the present invention.

[0057] Figure 3 A schematic diagram of a resonant switched capacitor module for a combined DC transformer with configurable turns ratio, a design method, and a system provided in an embodiment of the present invention;

[0058] Figure 4 A schematic diagram of a thyristor bridge arm structure for a combined DC transformer with configurable turns ratio, a design method and a system provided in an embodiment of the present invention;

[0059] Figure 5 A schematic diagram of a high-voltage conversion module based on a resonant switching module is provided for an embodiment of the present invention, which includes a combined DC transformer with configurable turns ratio, a design method, and a system.

[0060] Figure 6 This invention provides an embodiment of a configurable-ratio combined DC transformer, a design method, and a high-voltage conversion module based on a resonant switching module, which serves as the working principle of such a module. Figure 1 ;

[0061] Figure 7 This invention provides an embodiment of a configurable-ratio combined DC transformer, a design method, and a high-voltage conversion module based on a resonant switching module, which serves as the working principle of such a module. Figure 2 ;

[0062] Figure 8 This invention provides an embodiment of a configurable-ratio combined DC transformer, a design method, and a high-voltage conversion module based on a resonant switching module, which serves as the working principle of such a module. Figure 3 ;

[0063] Figure 9 This invention provides an embodiment of a configurable-ratio combined DC transformer, a design method, and a high-voltage conversion module based on a resonant switching module, which serves as the working principle of such a module. Figure 4 ;

[0064] Figure 10 Typical current and voltage waveforms of a high-voltage conversion module based on a resonant switching module, which is provided in an embodiment of the present invention, for a combined DC transformer with configurable turns ratio, design method and system;

[0065] Figure 11 A schematic diagram of an interleaved parallel high-voltage conversion module based on a resonant switch module is provided for an embodiment of the present invention, which includes a combined DC transformer with configurable turns ratio, a design method and system.

[0066] Figure 12A schematic diagram of a DC transformer consisting of multiple stages of interleaved parallel high-voltage conversion modules is provided as an embodiment of the present invention, including a configurable-ratio combined DC transformer, a design method and a system;

[0067] Figure 13 A graph of the high-voltage side voltage in a DC transformer, which is a combination DC transformer with configurable turns ratio, a design method and system provided in an embodiment of the present invention;

[0068] Figure 14 A voltage curve of the DC capacitor of a DC transformer is provided as an embodiment of the present invention, which includes a configurable-ratio combined DC transformer, a design method and a system.

[0069] Figure 15 The resonant current i of a resonant module in a combined DC transformer with configurable turns ratio, a design method, and a system provided in one embodiment of the present invention. r A graph showing the voltage of the resonant capacitor, the voltage of the thyristor bridge arm S1, and the voltage of the thyristor bridge arm S2.

[0070] Figure 16 This is an internal structural diagram of a computer device for a combined DC transformer with configurable turns ratio, a design method, and a system provided in one embodiment of the present invention. Detailed Implementation

[0071] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0072] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0073] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0074] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0075] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0076] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0077] Example 1

[0078] Reference Figures 1-16 This is the first embodiment of the present invention, which provides a combined DC transformer with configurable turns ratio, a design method, and a system, including:

[0079] Based on the requirements of the high-voltage operating environment of DC transformers, a resonant switched capacitor module is designed.

[0080] Furthermore, based on the DC transformer turns ratio required by the user, the number, connection method, and combination method of the resonant switched capacitor modules to be combined are determined.

[0081] Furthermore, based on the number of resonant switched capacitor modules to be combined, their connection method, their combination method, and the resonant switched capacitor modules, a DC transformer with a turns ratio configuration is established.

[0082] In one embodiment, a combination DC transformer with configurable turns ratio includes at least two interleaved parallel high-voltage conversion modules.

[0083] It should be noted that the interleaved parallel high-voltage conversion module includes at least two high-voltage conversion modules, and the interleaved parallel high-voltage conversion module is composed of at least two high-voltage conversion modules connected in parallel.

[0084] The high-voltage conversion module includes at least two resonant switched capacitor modules, which are connected in series; at least two interleaved parallel high-voltage conversion modules are cascaded to form a DC transformer.

[0085] Specifically, the resonant switched capacitor module includes, denoted as diodes and / or diode series valves as diode bridge arms, and denoted as thyristors and / or thyristor series valves as thyristor bridge arms;

[0086] Furthermore, the resonant switched capacitor module consists of a set of thyristor bridge arms containing anti-parallel diode bridge arms, a DC capacitor, and a resonant branch.

[0087] Furthermore, the thyristor bridge arm includes an auxiliary voltage equalization branch, which is used for voltage equalization of the devices and reliable turn-off of the thyristor bridge arm. The auxiliary voltage equalization circuit consists of at least one capacitor and at least one resistor.

[0088] Furthermore, the resonant branch exchanges energy between the DC capacitor and the input side through the energy transfer path composed of the resonant inductor and the resonant capacitor.

[0089] It should be noted that the high voltage conversion module includes, and the high voltage conversion module consists of at least two resonant switched capacitor modules and a set of thyristor bridge arms on the input side;

[0090] Furthermore, the DC capacitors of at least two resonant switched capacitor modules are connected in series with the input side to simultaneously support the output voltage. When the output voltage is n+1 times the input voltage, the high-voltage converter module consisting of at least two resonant switched capacitor modules and a set of thyristor bridge arms on the input side has a turns ratio of n+1.

[0091] Furthermore, establish n I Each high-voltage conversion module, and respectively converts n I The input and output sides of several high-voltage converter modules are connected in parallel to form an interleaved parallel high-voltage converter module. Taking a high-voltage converter module with a transformation ratio of 2 connected in interleaved parallel as an example, the structure of the interleaved parallel high-voltage converter module is shown in [reference needed]. Figure 11 .

[0092] It should be noted that when high-voltage converter modules are configured in an interleaved parallel structure, n I In high-voltage converter modules, current stress and capacitor voltage ripple are reduced compared to high-voltage converter modules that are not interleaved in parallel.

[0093] Furthermore, establish n s A high-voltage converter module with an interleaved parallel structure, and respectively converts n s The input and output sides of a high-voltage conversion module with an interleaved parallel structure are connected in series to form a high-ratio DC transformer.

[0094] Furthermore, establish n s n interleaved parallel high-voltage converter modules, and respectively n s The input and output sides of a high-voltage converter module with an interleaved parallel structure are connected in series to perform n... s If the transformation ratio of the high-voltage converter module is n+1, then the transformation ratio of the high-voltage converter modules connected in series is: This constitutes a change ratio DC transformer, n I and n s The turns ratio is determined by user requirements. Taking a cascaded interleaved parallel high-voltage converter module with a turns ratio of 2 as an example, see the section on DC transformers. Figure 12 .

[0095] It should be noted that the high-voltage conversion module also includes the following: when energy is transferred from the low-voltage side to the high-voltage side and all even-numbered switches are triggered, the second lower thyristor bridge arm on the input side is turned on. At this time, the voltage of the resonant capacitor is less than the voltage of the input capacitor, and the anti-parallel diode of the second right thyristor bridge arm of the resonant switching capacitor module is turned on under forward voltage drop. The resonant branch forms a resonant circuit with the input side through the thyristor bridge arm and the diode bridge arm.

[0096] Furthermore, if the resonant capacitor absorbs energy, the voltage rises and the resonant current returns to 0, at which point the thyristor bridge arm naturally turns off.

[0097] Furthermore, when energy is transferred from the low-voltage side to the high-voltage side, and the voltage of the resonant capacitor in the resonant branch absorbs energy and rises, the voltage of the resonant capacitor is greater than the voltage of the input capacitor. At this time, the second lower thyristor bridge arm is in the reverse recovery phase. Both the diode bridge arm and the thyristor bridge arm have voltage equalization branches. The resonant branch forms a reverse resonant circuit with the input side through the voltage equalization branch.

[0098] Furthermore, when the circuit parameters meet the overdamping condition, the reverse resonance monotonically decays, and the reverse resonance current passes through the voltage equalization branch of the reverse parallel diode of the second lower thyristor bridge arm. At this time, a constant reverse voltage is applied to the second lower thyristor bridge arm.

[0099] Furthermore, when the time for which the reverse voltage is applied is greater than the turn-off time of the second lower thyristor bridge arm, the second lower thyristor bridge arm is reliably turned off.

[0100] Furthermore, when energy is transferred from the low-voltage side to the high-voltage side, and all the odd-numbered switches are triggered, the first lower thyristor bridge arm on the input side is turned on. At this time, the voltage of the resonant capacitor is less than the voltage of the input capacitor. The anti-parallel diode of the first left thyristor bridge arm of the resonant switching capacitor module is turned on by the forward voltage drop. The resonant branch forms a resonant circuit through the thyristor bridge arm, the diode bridge arm, and the DC capacitor.

[0101] Furthermore, if the resonant capacitor releases energy, the voltage drops, the resonant current returns to 0, and the thyristor bridge arm naturally turns off.

[0102] Furthermore, when energy is transferred from the low-voltage side to the high-voltage side, and the voltage of the resonant capacitor in the resonant branch drops as it releases energy, the voltage of the resonant capacitor is less than the voltage of the DC capacitor. At this time, the first upper thyristor bridge arm on the input side is in the reverse recovery phase. Both the diode bridge arm and the thyristor bridge arm have voltage equalization branches. The resonant branch forms a reverse resonant circuit with the DC capacitor through the voltage equalization branch and the anti-parallel diode.

[0103] Furthermore, when the circuit parameters meet the overdamping condition, the reverse resonance monotonically decays, and the reverse resonance current passes through the voltage equalization branch of the reverse parallel diode of the first upper thyristor bridge arm. At this time, a constant reverse voltage is applied to the first upper thyristor bridge arm.

[0104] It should be noted that, furthermore, when the time for which the reverse voltage is applied is greater than the turn-off time of the first upper thyristor bridge arm, the first upper thyristor bridge arm is reliably turned off.

[0105] It should be noted that the high-voltage conversion module also includes switching the switch control sequence when energy is transferred from the high-voltage side to the low-voltage side; the rest of the working principle is the same as when energy is transferred from the low-voltage side to the high-voltage side.

[0106] It should be noted that when a set of thyristors containing anti-parallel diodes and / or thyristor series valves in the resonant switched capacitor module is replaced by a set of valves containing anti-diodes and / or diodes in series, the DC transformer becomes unidirectional.

[0107] In one embodiment, a combined DC transformer system with configurable turns ratio includes a resonant switched capacitor design module, a parameter determination module, and a turns ratio configuration module.

[0108] A resonant switched capacitor design module is used to design a resonant switched capacitor module according to the requirements of the high-voltage operating environment of a DC transformer.

[0109] The parameter determination module is used to determine the number, connection method, and combination method of the resonant switched capacitor modules to be combined according to the DC transformer turns ratio required by the user.

[0110] A turns ratio configuration module is used to establish a DC transformer with a turns ratio configuration based on the number, connection method, and combination method of the resonant switched capacitor modules to be combined and the resonant switched capacitor modules.

[0111] The above-mentioned unit modules can be embedded in the processor of the computer device in hardware form or independent of it, or they can be stored in the memory of the computer device in software form, so that the processor can call and execute the corresponding operations of the above modules.

[0112] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 16 As shown, the computer device includes a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. When executed by the processor, the computer program implements a design method for a combined DC transformer with configurable turns ratio. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device casing, or an external keyboard, touchpad, or mouse.

[0113] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0114] Based on the requirements of the high-voltage operating environment of DC transformers, a resonant switched capacitor module is designed.

[0115] Based on the DC transformer turns ratio required by the user, determine the number, connection method, and combination method of the resonant switched capacitor modules to be combined.

[0116] The DC transformer with the turns ratio configuration is established based on the number of resonant switched capacitor modules to be combined, their connection method, their combination method, and the turns ratio configuration of the resonant switched capacitor modules.

[0117] Example 2

[0118] Reference Figure 1 , Figures 13-15 As one embodiment of the present invention, a combined DC transformer with configurable turns ratio, a design method and a system are provided. To verify the beneficial effects of the present invention, comparative experiments are conducted for scientific demonstration.

[0119] based on Figure 1The DC transformer structure shown is built using MATLAB / Simulink software. Figure 12 The DC transformer structure shown is used for simulation verification of this topology. The simulation parameters are shown in Table 1 below.

[0120] Table 1: Simulation Parameters of DC Transformer

[0121] Input voltage 10kV Output voltage 160kV Switching frequency 200Hz resonant frequency 300Hz Transmission power 100MW Serial series 4 High voltage converter module turns ratio 2 Transformer turns ratio 16

[0122] Under the operating conditions shown in the table above, with a given input voltage of 10kV and an output voltage of 160kV, a DC transformer with a turns ratio of 16 is formed by cascading four high-voltage conversion modules with a turns ratio of 2; the rated transmission power is 100MW; to ensure reliable thyristor turn-off, the switching frequency is set to 200Hz and the resonant frequency to 300Hz. The simulation results are as follows. Figures 13-15 As shown.

[0123] Figure 13 The curve shown is the high-voltage side output voltage curve in embodiment two of the present invention. It can be seen that under a fixed turns ratio, the high-voltage side voltage V dc2 The voltage amplitude fluctuates around 160kV.

[0124] Figure 14 The voltage curve of the DC capacitor in embodiment two of the present invention shows that the voltage of the DC capacitor fluctuates around 10kV, 20kV, 40kV and 80kV respectively, achieving a 2-fold voltage boost between each two stages, and also achieving self-balancing capability.

[0125] Figure 15 The resonant current i of one of the resonant modules in embodiment two of the present invention r The curves depict the resonant capacitor voltage and the voltages of thyristor bridge arms S1 and S2. Specifically: When thyristor bridge arm S2 is turned on, the resonant current starts resonating from zero, and the resonant capacitor voltage starts resonating and rising from its minimum value. At this point, the conduction voltage of thyristor bridge arm S2 is zero. When the resonant current resonates to zero again, the thyristor bridge arm is turned off. At this time, thyristor bridge arm T2 experiences a reverse voltage drop, enabling reliable thyristor turn-off.

[0126] The above examples demonstrate that the DC transformer implemented in this example, which uses a resonant switched capacitor module based on thyristor bridge arms, can reliably turn off. By utilizing the circuit structure, a stable reverse voltage is applied to the thyristor bridge arms to ensure reliable turn-off; no voltage equalization control strategy is required, and self-balancing of all DC capacitor voltages is achieved.

[0127] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

[0128] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0129] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0130] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0131] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0132] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0133] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A combined DC transformer with configurable turns ratio, characterized in that: Includes at least two interleaved parallel high-voltage converter modules, The interleaved parallel high-voltage conversion module includes at least two high-voltage conversion modules, and the interleaved parallel high-voltage conversion module is composed of at least two high-voltage conversion modules connected in parallel; The high-voltage conversion module includes at least two resonant switched capacitor modules, and the high-voltage conversion module is composed of at least two resonant switched capacitor modules connected in series. The at least two interleaved parallel high-voltage conversion modules are cascaded to form a DC transformer; The resonant switched capacitor module includes, A diode or / and a diode series valve system is referred to as a diode bridge arm, and a thyristor or / and a thyristor series valve system is referred to as a thyristor bridge arm. The resonant switched capacitor module consists of a set of thyristor bridge arms containing anti-parallel diode bridge arms, a DC capacitor, and a resonant branch. The thyristor bridge arm includes an auxiliary voltage equalization branch. The auxiliary voltage equalization circuit is used for voltage equalization of devices and reliable turn-off of the thyristor bridge arm. The auxiliary voltage equalization circuit consists of at least one capacitor and at least one resistor. The resonant branch exchanges energy between the DC capacitor and the input side through an energy transfer path composed of a resonant inductor and a resonant capacitor.

2. The combined DC transformer with configurable turns ratio as described in claim 1, characterized in that: The high-voltage conversion module includes, The high-voltage conversion module consists of at least two resonant switched capacitor modules and a set of thyristor bridge arms on the input side; The DC capacitors of the at least two resonant switched capacitor modules are connected in series with the input side to simultaneously support the output voltage. When the output voltage is n+1 times the input voltage, the high-voltage conversion module composed of the at least two resonant switched capacitor modules and a set of thyristor bridge arms on the input side has a transformation ratio of n+1.

3. The combined DC transformer with configurable turns ratio as described in claim 1, characterized in that: It also includes, Establish Each high-voltage conversion module, and respectively converts the... The input side of each high-voltage conversion module is connected in parallel, and the output side is connected in parallel to form a high-voltage conversion module with an interleaved parallel structure. When high-voltage converter modules are configured in an interleaved parallel structure The current stress and capacitor voltage ripple in the high-voltage conversion module are reduced compared to the high-voltage conversion module that is not interleaved in parallel. Establish A high-voltage conversion module with an interleaved parallel structure, and respectively converts the... The input and output sides of a high-voltage conversion module with an interleaved parallel structure are connected in series to form a high-ratio DC transformer.

4. The combined DC transformer with configurable turns ratio as described in claim 3, characterized in that: It also includes, Establish Each of the aforementioned interleaved parallel high-voltage conversion modules, and respectively converts the... The input and output sides of a high-voltage converter module with an interleaved parallel structure are connected in series for... If the transformation ratio of the high-voltage converter module is n+1, then the transformation ratio of the high-voltage converter modules connected in series is: This constitutes a change ratio The DC transformer, the as well as Determined by the variation ratio of user needs.

5. The combined DC transformer with configurable turns ratio as described in claim 4, characterized in that: The high-voltage conversion module also includes, When energy is transferred from the low-voltage side to the high-voltage side, and all even-numbered switches are triggered, the second lower thyristor bridge arm on the input side conducts. At this time, the voltage of the resonant capacitor is less than the voltage of the input capacitor, and the anti-parallel diode of the second right thyristor bridge arm of the resonant switching capacitor module conducts under forward voltage drop. The resonant branch forms a resonant circuit with the input side through the thyristor bridge arm and the diode bridge arm. If the resonant capacitor absorbs energy, the voltage rises and the resonant current returns to 0, at which point the thyristor bridge arm naturally turns off.

6. The combined DC transformer with configurable turns ratio as described in claim 5, characterized in that: The high-voltage conversion module also includes, When energy is transferred from the low-voltage side to the high-voltage side, and the voltage of the resonant capacitor in the resonant branch absorbs energy and rises, the voltage of the resonant capacitor is greater than the voltage of the input capacitor. At this time, the second lower thyristor bridge arm is in the reverse recovery stage. Both the diode bridge arm and the thyristor bridge arm have voltage equalization branches. The resonant branch forms a reverse resonant circuit with the input side through the voltage equalization branch. When the circuit parameters meet the overdamping condition, the reverse resonance monotonically decays, and the reverse resonance current passes through the voltage equalization branch of the reverse parallel diode of the second lower thyristor bridge arm. At this time, a constant reverse voltage is applied to the second lower thyristor bridge arm. When the time for applying the reverse voltage is greater than the turn-off time of the second lower thyristor bridge arm, the second lower thyristor bridge arm is reliably turned off.

7. The combined DC transformer with configurable turns ratio as described in claim 6, characterized in that: The high-voltage conversion module also includes, When energy is transferred from the low-voltage side to the high-voltage side, and all odd-numbered switches are triggered, the first lower thyristor bridge arm on the input side conducts. At this time, the voltage of the resonant capacitor is less than the voltage of the input capacitor. ， The anti-parallel diode of the first left thyristor bridge arm of the resonant switched capacitor module conducts under forward voltage drop, and the resonant branch forms a resonant circuit through the thyristor bridge arm, the diode bridge arm, and the DC capacitor. ； If the resonant capacitor releases energy, the voltage drops, the resonant current returns to 0, and the thyristor bridge arm naturally turns off.

8. The combined DC transformer with configurable turns ratio as described in claim 7, characterized in that: The high-voltage conversion module also includes, When energy is transferred from the low-voltage side to the high-voltage side, and the voltage of the resonant capacitor in the resonant branch drops as it releases energy, the voltage of the resonant capacitor is less than the voltage of the DC capacitor. At this time, the first upper thyristor bridge arm on the input side is in the reverse recovery phase. Both the diode bridge arm and the thyristor bridge arm have voltage equalization branches. The resonant branch forms a reverse resonant circuit with the DC capacitor through the voltage equalization branch and the anti-parallel diode. When the circuit parameters meet the overdamping condition, the reverse resonance monotonically decays, and the reverse resonance current passes through the voltage equalization branch of the reverse parallel diode of the first upper thyristor bridge arm. At this time, a constant reverse voltage is applied to the first upper thyristor bridge arm. When the time for applying the reverse voltage is greater than the turn-off time of the first upper thyristor bridge arm, the first upper thyristor bridge arm is reliably turned off.

9. The combined DC transformer with configurable turns ratio as described in claim 8, characterized in that: The high-voltage conversion module also includes a switch control sequence that is switched when energy is transmitted from the high-voltage side to the low-voltage side, and the rest of the working principle is the same as that of transmitting energy from the low-voltage side to the high-voltage side.

10. The combined DC transformer with configurable turns ratio as described in claim 9, characterized in that: It also includes, When a set of thyristors containing anti-parallel diodes and / or thyristor series valves in a resonant switched capacitor module is replaced by a set of valves containing anti-diodes and / or diodes in series, the DC transformer becomes unidirectional.

11. A design method for a combined DC transformer with configurable turns ratio as described in claim 1, characterized in that: include, Design a resonant switched capacitor module based on the requirements of high-voltage operation environment of DC transformers; Based on the DC transformer turns ratio required by the user, determine the number, connection method, and combination method of the resonant switched capacitor modules to be combined. The DC transformer is configured with turns ratio based on the number, connection method, and combination method of the resonant switched capacitor modules to be combined.

12. A system using a combined DC transformer with configurable turns ratio as described in claim 1, characterized in that: It includes a resonant switched capacitor design module, a parameter determination module, and a turns ratio configuration module. A resonant switched capacitor design module is used to design a resonant switched capacitor module according to the requirements of the high-voltage operating environment of a DC transformer. The parameter determination module is used to determine the number, connection method, and combination method of the resonant switched capacitor modules to be combined according to the DC transformer turns ratio required by the user. A turns ratio configuration module is used to establish a DC transformer with a turns ratio configuration based on the number, connection method, and combination method of the resonant switched capacitor modules to be combined and the resonant switched capacitor modules.

13. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method of claim 11.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method of claim 11.

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