Matrix converter system and control method thereof

Abstract

The application provides a matrix converter system and a control method thereof. The matrix converter system comprises a first output port and a second output port, at least two phases, N converter valve bridge arms, Q first magnetic elements, the i-th first magnetic element comprises N first ports, M second ports, the N first ports of the i-th first magnetic element are connected in series with one end of the N converter valve bridge arms respectively, the other end of the N converter valve bridge arms is connected with any one phase of the first output port respectively, and the other end of at least one converter valve bridge arm is connected with a phase of the first output port which is different from the phase of the first output port connected with the other end of the remaining converter valve bridge arms, and the M second ports of the i-th first magnetic element are connected with any one phase of the second output port respectively, and at least one second port is connected with a phase of the second output port which is different from the phase of the second output port connected with the remaining second ports. i i i i i i ​​​​​​

Description

Technical Field

[0001] This application relates to the field of power electronics application technology, and more specifically, to a matrix converter system and its control method. Background Technology

[0002] In low-frequency power transmission systems, AC-AC converters are used for power frequency and low-frequency voltage conversion. In high-voltage applications, the most common and mature AC-AC converter is the modular multilevel matrix converter (M3C). However, this converter requires nine links, resulting in a large number of modules and high system cost. Therefore, a method is adopted to reduce the voltage level on the converter valve side by adding isolation transformers. This reduces the number of modules and lowers system cost while ensuring the current stress on the switching devices. However, the system still requires magnetic components such as reactors and isolation transformers, resulting in a still large system footprint.

[0003] Patent CN113381620A proposes a circuit that combines a transformer and a reactor, eliminating the need for an external isolation transformer. However, in this scheme, the three primary windings of the transformer carry mixed-frequency currents, while the secondary winding carries low-frequency currents, which can lead to excessive excitation current in the core of the actual transformer.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] This application aims to provide a matrix converter system and its control method, which can fully consider magnetic coupling and magnetic balance characteristics, reduce the design requirements of magnetic components, and reduce the overall system cost and footprint.

[0006] According to one aspect of this application, a matrix converter system is proposed, comprising:

[0007] The first output port includes at least two phases;

[0008] The second output port includes at least two phases;

[0009] There are N converter valve bridge arms, where N is an integer greater than or equal to 2;

[0010] Q first magnetic elements, where Q is an integer greater than or equal to 1;

[0011] The i-th first magnetic element includes N i The first port, M i There are two second ports, where Q*N i=N, i∈[1,Q],N i M is an integer greater than or equal to 2. i It is an integer greater than or equal to 2;

[0012] N of the i-th first magnetic element i Each of the first ports is connected in series with the N i One end of the aforementioned converter valve bridge arm, N i The other end of each of the converter valve bridge arms is connected to any one phase of the first output port, and the phase to which the other end of at least one of the converter valve bridge arms is connected to the first output port is different from the phase to which the other end of the other converter valve bridge arms is connected to the first output port.

[0013] M of the i-th first magnetic element i Each of the second ports is connected to any one of the phases of the second output port, and at least one of the second ports is connected to a different phase than the other two second ports are connected to the second output port.

[0014] According to some embodiments, it also includes:

[0015] Q second magnetic elements, wherein the j-th second magnetic element includes K j A third port, L j There are four fourth ports, where Q*K j =N, j∈[1, Q], N j M is an integer greater than or equal to 2. j It is an integer greater than or equal to 2;

[0016] The Kj third ports of the j-th second magnetic element are respectively connected in series with the K j The other end of the aforementioned converter valve bridge arm;

[0017] The j-th second magnetic element L j Each of the fourth ports is connected to any one of the phases of the first output port, and at least one of the fourth ports is connected to a different phase from the other fourth ports to the first output port.

[0018] According to some embodiments, it also includes:

[0019] A first frequency AC system is connected to the first output port in phase sequence; and

[0020] The second frequency AC system is connected to the second output port in phase order.

[0021] According to some embodiments, it also includes a first buffer reactance and a second buffer reactance, wherein,

[0022] The first output port of the matrix converter system is connected to the first buffer reactor in phase order, and then connected to the first frequency AC system.

[0023] The second output port of the matrix converter system is connected to the second buffer reactor in phase order, and then connected to the second frequency AC system.

[0024] According to some embodiments, it also includes a first soft-start branch and a second soft-start branch, wherein,

[0025] The first output port of the matrix converter system is connected to the first soft-start branch and then to the first frequency AC system.

[0026] The second output port of the matrix converter system is connected to the second soft-start branch and then to the second frequency AC system.

[0027] According to some embodiments, one of the first soft-start branch and the second soft-start branch includes a charging switch, a charging resistor, and a bypass switch, while the other soft-start branch includes an isolating switch; or

[0028] Both the first soft-start branch and the second soft-start branch include the charging switch, the charging resistor, and the bypass switch;

[0029] Wherein, the charging switch is connected in series with the charging resistor, and the bypass switch is connected in parallel with the charging resistor; or

[0030] The bypass switch is connected in parallel with the branch of the charging switch and the charging resistor that are connected in series.

[0031] According to some embodiments, the first magnetic element and the second magnetic element include:

[0032] Coupled inductors consist of two or more windings, with any one winding constituting a phase; or

[0033] A two-winding transformer includes a primary winding and a secondary winding, wherein: one end of the primary winding and one end of the secondary winding are in one phase, and the other end of the primary winding and the other end of the secondary winding are in another phase; or

[0034] A multiphase transformer includes a primary winding and a secondary winding, wherein the primary winding and the secondary winding of the multiphase transformer are connected in a star or delta configuration, and the terminals led out from the corresponding phase windings constitute one phase.

[0035] According to some embodiments, the multiphase transformer adopts the star connection method, and the grounding method includes: direct grounding, grounding through the target coil, grounding through the target resistor, or no grounding; or

[0036] The multiphase transformer adopts a delta connection method, and the grounding methods include: grounding through a Z-type transformer, grounding after three reactors, or no grounding.

[0037] According to some embodiments, the converter valve bridge arm includes n sub-modules connected in series, where n is a positive integer; wherein, each sub-module includes a full-bridge circuit, and each sub-module is connected in series through an AC port.

[0038] According to another aspect of this application, a control method for a matrix converter system is proposed. The matrix converter system includes a first soft-start branch and a second soft-start branch. One of the first and second soft-start branches includes a charging switch, a charging resistor, and a bypass switch, while the other soft-start branch includes an isolating switch, or both include the charging switch, the charging resistor, and the bypass switch. A first output port includes at least two phases. A second output port includes at least two phases. N converter valve bridge arms, where N is an integer greater than or equal to 2. Q first magnetic elements, where Q is an integer greater than or equal to 1. The i-th first magnetic element includes Ni first ports and Mi second ports, where Q*Ni = N, i ∈ [1, Q], and Ni... Mi is an integer greater than or equal to 2; the Ni first ports of the i-th first magnetic element are respectively connected in series with one end of the Ni converter valve bridge arms, and the other ends of the Ni converter valve bridge arms are respectively connected to any one phase of the first output port, and the phase of the other end of at least one converter valve bridge arm connected to the first output port is different from the phase of the other end of the converter valve bridge arms connected to the first output port; the Mi second ports of the i-th first magnetic element are respectively connected to any one phase of the second output port, and the phase of the second port connected to the second output port is different from the phase of the other second ports connected to the second output port. The control method of the matrix converter system includes:

[0039] Start from the first frequency AC system or start from the second frequency AC system.

[0040] According to some embodiments, the initiation from the first frequency AC system includes:

[0041] If the first soft starter branch or the second soft starter branch includes a disconnect switch, close the disconnect switch;

[0042] Close the charging switch of the first soft starter branch;

[0043] In response to the completion of charging of the converter valve bridge arm, the bypass switch of the first soft start branch is closed;

[0044] Unlock the converter valve bridge arm;

[0045] Close the charging switch of the second soft starter branch and close the bypass switch of the second soft starter branch.

[0046] According to some embodiments, the startup from the second frequency AC system includes:

[0047] If the second soft starter branch or the first soft starter branch includes a disconnect switch, close the disconnect switch;

[0048] Close the charging switch of the second soft start branch;

[0049] In response to the completion of charging of the converter valve bridge arm, the bypass switch of the second soft start branch is closed;

[0050] Unlock the converter valve bridge arm;

[0051] Close the charging switch of the first soft starter branch and close the bypass switch of the first soft starter branch.

[0052] This application provides a matrix converter system and its control method. By analyzing the operating current characteristics of the matrix converter, appropriate converter valve arms are selected and grouped. After grouping, the mixing current in the converter valve arms can achieve three-phase or multi-phase balance in two frequency dimensions. The arm reactors are configured as coupled reactors that can achieve magnetic balance. After the magnetically balanced coupled reactors are replaced with three-phase or multi-phase transformers, both the primary and secondary sides of the transformer can achieve magnetic balance, which can reduce the design requirements of the three-phase transformer used and indirectly reduce its cost and footprint.

[0053] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0054] The above and other objects, features, and advantages of this application will become more apparent from the detailed description of exemplary embodiments with reference to the accompanying drawings. The drawings described below are merely some embodiments of this application and are not intended to limit the scope of this application.

[0055] Figure 1 A connection diagram of a matrix converter system according to an exemplary embodiment is shown;

[0056] Figure 2A schematic diagram of a soft-start branch of an exemplary embodiment is shown;

[0057] Figure 3 Another embodiment of an exemplary soft-start branch is shown in the diagram;

[0058] Figure 4 A schematic diagram of an exemplary buffer reactance is shown;

[0059] Figure 5 A schematic diagram of a magnetic element is shown in an exemplary embodiment;

[0060] Figure 6 Another embodiment of an exemplary magnetic element schematic diagram is shown;

[0061] Figure 7 Another embodiment of an exemplary magnetic element schematic diagram is shown;

[0062] Figure 8 Another embodiment of an exemplary magnetic element schematic diagram is shown;

[0063] Figure 9 A schematic diagram of a full-bridge circuit of an exemplary embodiment is shown;

[0064] Figure 10 A schematic diagram of a matrix converter system of an exemplary embodiment is shown;

[0065] Figure 11 Another embodiment of an exemplary matrix converter system schematic diagram is shown;

[0066] Figure 12 Another embodiment of an exemplary matrix converter system schematic diagram is shown;

[0067] Figure 13 A flowchart illustrating a control method for a matrix converter system in an exemplary embodiment is shown.

[0068] Figure 14 Another embodiment of a control method flowchart for an exemplary matrix converter system is shown. Detailed Implementation

[0069] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0070] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. In these cases, well-known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.

[0071] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0072] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0073] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments, and the modules or processes in the drawings are not necessarily essential for implementing this application, and therefore cannot be used to limit the scope of protection of this application.

[0074] This application proposes a matrix converter system, comprising: a first output port including at least two phases; a second output port including at least two phases; N converter valve bridge arms, where N is an integer greater than or equal to 2; Q first magnetic elements, where Q is an integer greater than or equal to 1; the i-th first magnetic element includes N... i The first port, M i There are two second ports, where Q*N i =N, i∈[1,Q],N i M is an integer greater than or equal to 2. i N is an integer greater than or equal to 2; N is the first magnetic element of the i-th element. i Each of the first ports is connected in series with N. i One end of a converter valve bridge arm, N iThe other end of each converter valve bridge arm is connected to any one phase of the first output port, and the phase to which the other end of at least one converter valve bridge arm is connected to the first output port is different from the phase to which the other ends of the converter valve bridge arms are connected to the first output port; the M of the i-th first magnetic element i Each second port is connected to any one phase of the second output port, and at least one second port is connected to a different phase than the other second ports are connected to the second output port.

[0075] Figure 1 A schematic diagram of the connection of a matrix converter system according to an exemplary embodiment is shown.

[0076] like Figure 1 As shown, component 1001 represents the first output port of the matrix converter system, with phases A, B, and C shown in the figure; component 1002 represents the second output port of the matrix converter system, with phases a, b, and c shown in the figure; components 1031, 1032, and 1033 represent the first magnetic element, connected in series between the first output port 1001 of the matrix converter system and the converter valve bridge arm 105; component 105 represents the converter valve bridge arm.

[0077] The converter valve bridge arm 105 comprises n sub-modules connected in series, where n is a positive integer greater than or equal to 1; these n sub-modules are constructed using a full-bridge circuit and connected in series through AC ports. For example... Figure 1 As shown, components 1051 to 105N represent n sub-modules connected in series.

[0078] According to some embodiments, the matrix converter system further includes Q second magnetic elements, wherein the j-th second magnetic element includes K... j A third port, L j There are four fourth ports, where Q*K j =N, j∈[1, Q], N j M is an integer greater than or equal to 2. j K is an integer greater than or equal to 2; the K of the j-th second magnetic element j Each of the third ports is connected in series with K. j The other end of the converter valve bridge arm; L of the j-th second magnetic element j Each of the fourth ports is connected to any one of the phases of the first output port, and at least one of the fourth ports is connected to a different phase of the first output port than the other fourth ports are connected to the first output port.

[0079] According to an example embodiment, the matrix converter system of this application further includes a second magnetic element, connected in series between the second output port 1002 of the matrix converter system and the converter valve bridge arm 105. Figure 1As shown, components 1041, 1042 and 1043 represent the second magnetic element.

[0080] According to some embodiments, the matrix converter system further includes a first frequency AC system 101 and a second frequency AC system 102; the first output port 1001 of the matrix converter system is connected to the first frequency AC system 101 in phase order; the second output port 1002 of the matrix converter system is connected to the second frequency AC system 102 in phase order. Figure 1 As shown, component 1001 can be connected to the first frequency AC system 101 according to phases A, B, and C, and component 1002 can be connected to the second frequency AC system 102 according to phases a, b, and c.

[0081] According to some embodiments, the matrix converter system further includes: a first buffer reactor and / or a second buffer reactor. For example... Figure 1 As shown, component 108 represents the first buffer reactance, and component 109 represents the second buffer reactance; Figure 4 This is a schematic diagram of the buffer reactance.

[0082] According to some embodiments, the first output port 1001 of the matrix converter system is connected to the first buffer reactor 108 in phase order, and then connected to the first frequency AC system 101; the second output port 1002 of the matrix converter system is connected to the second buffer reactor 109 in phase order, and then connected to the second frequency AC system 102.

[0083] According to some embodiments, the matrix converter system further includes a first soft-start branch and a second soft-start branch; such as Figure 1 As shown, component 106 represents the first soft start branch, and component 107 represents the second soft start branch.

[0084] The first output port 1001 of the matrix converter system is connected to the first soft start branch 106 and / or the first buffer reactor 108, and then connected to the first frequency AC system 101; the second output port 1002 of the matrix converter system is connected to the second soft start branch 107 and / or the second buffer reactor 109, and then connected to the second frequency AC system 102.

[0085] This application proposes a matrix converter system that optimizes the configuration of magnetic components. The magnetic components are connected to the converter valve bridge arms according to phase, and then connected to the corresponding phases of the first output port and the second output port. The bridge arm combination is reasonably configured to optimize the operating state of the magnetic components and reduce the magnetic saturation of magnetic devices such as bridge arm reactance or transformers.

[0086] Figure 2 A schematic diagram of a soft-start branch of an exemplary embodiment is shown.

[0087] In the first soft-start branch and the second soft-start branch, at least one soft-start branch adopts a structure including a charging switch, a charging resistor, and a bypass switch. The specific connection method of the soft-start branch is as follows: the charging switch and the charging resistor of the soft-start branch are connected in series, and the bypass switch and the charging resistor are connected in parallel; or the bypass switch of one of the soft-start branches is connected in parallel with the branch in which the charging switch and the charging resistor are connected in series.

[0088] Figure 2 and Figure 3 The diagram shows two connection methods for the first soft starter branch or the second soft starter branch. Components 201 and 301 represent charging switches, components 202 and 302 represent charging resistors, and components 203 and 204 represent bypass switches.

[0089] According to some embodiments, in the first soft start branch and the second soft start branch, at least one soft start branch adopts a structure including a charging switch, a charging resistor and a bypass switch, and the remaining branches adopt an isolating switch; or all soft start branches include a structure including a charging switch, a charging resistor and a bypass switch.

[0090] Figure 5 A schematic diagram of a magnetic element is shown in an exemplary embodiment.

[0091] The first magnetic element and the second magnetic element include the following three forms:

[0092] Form 1: Coupled inductor, the first magnetic element and the second magnetic element include two or more windings, any one of the windings is a phase;

[0093] Form 2: Two-winding transformer, i.e. single-phase transformer. The first and second magnetic elements include a primary winding and a secondary winding, with a phase number of 2. One end of any primary winding and one end of any secondary winding constitute one phase, and one end of the remaining primary winding and one end of the secondary winding constitute the other phase.

[0094] Form 3: Multiphase transformer, consisting of primary winding and secondary winding; the primary and secondary windings are connected in a star or delta configuration, and the terminals of the corresponding phase windings are one phase.

[0095] like Figure 5 As shown, this represents a three-phase coupled inductor, with windings 401, 402, and 403 each being a phase.

[0096] like Figure 6 As shown, this represents a two-winding transformer, with windings 501 and 502 each representing a phase.

[0097] like Figure 7As shown, this is a three-phase transformer with a "star" connection, where windings 601, 602, and 603 each represent a phase.

[0098] like Figure 8 As shown, this is a three-phase transformer with a "star-delta" connection. Windings 701, 702, and 703 each represent a phase.

[0099] According to some embodiments, in Form 3, in particular, the multiphase transformer of the first magnetic element and the second magnetic element is a three-phase transformer, which adopts a "star" or "star-delta" connection method.

[0100] For windings using a star connection, the grounding method is determined according to system requirements. Grounding methods include: direct grounding, grounding through the target coil, grounding through the target resistor, and no grounding.

[0101] For windings using delta connections, the grounding method is determined according to system requirements. Grounding methods include: grounding through a Z-type transformer, grounding through three reactors, and no grounding.

[0102] like Figure 7 As shown, winding 604 represents the direct grounding method in a star-connected winding.

[0103] like Figure 8 As shown, winding 704 represents the grounding method via a Z-type transformer in a delta-connected winding, including a Z-type transformer, three-phase reactor, surge arrester, and grounding resistor.

[0104] Figure 9 A schematic diagram of a full-bridge circuit of an exemplary embodiment is shown.

[0105] like Figure 9 As shown, the full-bridge circuit includes an AC port 901, a controllable switching device 902, and a capacitor 903 connected in parallel.

[0106] According to some embodiments, the full-bridge circuit may also include an energy storage element 904, such as a supercapacitor and a battery, connected in parallel with the capacitor element 903.

[0107] Figure 10 A schematic diagram of a matrix converter system of an exemplary embodiment is shown.

[0108] like Figure 10As shown, the matrix converter system includes three first magnetic elements, each with three phases, and nine converter valve arms. The first output port includes three phases A, B, and C, and the second output port includes three phases a, b, and c. The phase numbers of the three first magnetic elements are denoted as phases 1-9; phases 1, 2, and 3 are located on the first magnetic element; phases 4, 5, and 6 are located on the second magnetic element; and phases 7, 8, and 9 are located on the third magnetic element. The system connection is as follows:

[0109] One end of phase 1 is connected to the first output port A phase, and the other end is connected to the second output port a phase;

[0110] One end of phase 2 is connected to the first output port B phase, and the other end is connected to the second output port b phase;

[0111] One end of phase 3 is connected to the first output port C phase, and the other end is connected to the second output port C phase;

[0112] One end of phase 4 is connected to the first output port A phase, and the other end is connected to the second output port b phase;

[0113] One end of phase 5 is connected to the first output port B phase, and the other end is connected to the second output port c phase;

[0114] One end of phase 6 is connected to the first output port C phase, and the other end is connected to the second output port a phase;

[0115] One end of phase 7 is connected to the first output port A phase, and the other end is connected to the second output port c phase;

[0116] One end of phase 8 is connected to the first output port B phase, and the other end is connected to the second output port a phase;

[0117] One end of phase 9 is connected to the first output port C phase, and the other end is connected to the second output port b phase.

[0118] Figure 10 and Figure 11 Two common matrix converter systems are shown, each consisting of three first magnetic elements, each with a phase number of three, and nine converter valve arms; wherein, Figure 10 This is an example of a matrix converter system using three-phase coupled inductors. Figure 11 This is an example of a matrix converter system using three-phase transformers.

[0119] Figure 12 The diagram shows a matrix converter system comprising two phase-specific first magnetic elements, employing a two-phase conversion matrix converter system with a dual-winding transformer.

[0120] According to some embodiments, the number of converter valve bridge arms is the same as the number of phases of the first magnetic element.

[0121] This application provides a matrix converter system. By analyzing the operating current characteristics of the matrix converter, appropriate converter valve arms are selected and grouped. According to an example embodiment, such as... Figure 10 As shown, the converter valve bridge arms with phases 1-3 of the first magnetic element form one group, the converter valve bridge arms with phases 4-6 of the first magnetic element form another group, and the converter valve bridge arms with phases 7-9 of the first magnetic element form yet another group. After grouping, the mixing current in the converter valve bridge arms can achieve three-phase or multi-phase balance in two frequency dimensions, thus forming a coupled reactor capable of achieving magnetic balance. One end of phases 1-9 is connected to the three phases ABC of the first output port, and the other end is connected to the three phases abc of the second output port. This can optimize the operating state of the magnetic element and reduce the magnetic saturation of magnetic devices such as bridge arm reactors or transformers.

[0122] By replacing the magnetically balanced coupling reactor with a three-phase or multi-phase transformer, magnetic balance can be achieved on both the primary and secondary sides of the transformer. This reduces the design requirements of the three-phase transformer used, indirectly reducing its cost and footprint.

[0123] Figure 13 A flowchart illustrating a control method for a matrix converter system of an exemplary embodiment is shown.

[0124] According to some embodiments, the control process of the matrix converter system includes starting from a first frequency AC system 101 and starting from a second frequency AC system 102.

[0125] According to some embodiments, if the input side of the matrix converter system is a first-frequency AC system, the startup process is as follows:

[0126] S11: If there is an isolating switch in the first soft starter branch and the second soft starter branch, close the isolating switch; otherwise, skip this step.

[0127] S12: Close the charging switch of the first soft starter branch, and after the converter valve bridge arm module has completed charging, close the bypass switch of the first soft starter branch.

[0128] S13: Unlock the converter valve bridge arm;

[0129] According to some embodiments, some sub-modules in the converter valve bridge arm are unlocked according to the actual system requirements.

[0130] S14: The second soft starter branch is an isolating switch, and the start-up process has ended;

[0131] According to some embodiments, if the second soft start branch is an isolating switch, the start-up ends; if the second soft start branch is not an isolating switch, then proceed to S15.

[0132] S15: Close the charging switch of the second soft starter branch, and after a delay, close the bypass switch of the second soft starter branch to end the start-up process.

[0133] According to some embodiments, the delay time depends on the size of the capacitor in the charging switch.

[0134] Figure 14 Another embodiment of a control method flowchart for an exemplary matrix converter system is shown.

[0135] According to some embodiments, if the input side of the matrix converter system is a second-frequency AC system, the startup process is as follows:

[0136] S21: If there is an isolating switch in the first soft starter branch and the second soft starter branch, close the isolating switch; otherwise, skip this step.

[0137] S22: Close the charging switch of the second soft starter branch, and after the converter valve bridge arm module has completed charging, close the bypass switch of the second soft starter branch.

[0138] S23: Unlock the converter valve bridge arm;

[0139] According to some embodiments, some sub-modules in the converter valve bridge arm are unlocked according to the actual system requirements.

[0140] S24: The first soft starter branch is an isolating switch, and the start-up process has ended;

[0141] According to some embodiments, if the first soft start branch is an isolating switch, the start-up ends; if the first soft start branch is not an isolating switch, then proceed to S25.

[0142] S25: Close the charging switch of the first soft starter branch, and after a delay, close the bypass switch of the first soft starter branch to end the start-up process.

[0143] According to some embodiments, the delay time depends on the size of the capacitor in the charging switch.

[0144] It should be clearly understood that this application describes how specific examples are formed and used, but this application is not limited to any details of these examples. Rather, based on the teachings of the disclosure of this application, these principles can be applied to many other embodiments.

[0145] Furthermore, it should be noted that the above figures are merely illustrative representations of the processes included in the method according to exemplary embodiments of this application, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0146] Exemplary embodiments of this application have been specifically shown and described above. It should be understood that this application is not limited to the detailed structures, arrangements, or implementation methods described herein; rather, this application is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. A matrix converter system, characterized in that, include: The first output port includes at least two phases; The second output port includes at least two phases; There are N converter valve bridge arms, where N is an integer greater than or equal to 2; Q first magnetic elements, where Q is an integer greater than or equal to 1; Wherein, the i-th first magnetic element includes N i The first port, M i There are two second ports, where Q*N i =N, i∈[1,Q],N i M is an integer greater than or equal to 2. i It is an integer greater than or equal to 2; N of the i-th first magnetic element i Each of the first ports is connected in series with the N i One end of the aforementioned converter valve bridge arm, N i The other end of each of the converter valve bridge arms is connected to any one phase of the first output port, and the phase to which the other end of at least one of the converter valve bridge arms is connected to the first output port is different from the phase to which the other end of the other converter valve bridge arms is connected to the first output port. M of the i-th first magnetic element i Each of the second ports is connected to any one of the phases of the second output port, and at least one of the second ports is connected to a different phase than the other two second ports are connected to the second output port. The matrix converter system further includes: First frequency AC system and second frequency AC system; First buffer reactor and second buffer reactor; and / or first soft start branch and second soft start branch; The first output port of the matrix converter system is connected to the first buffer reactor in phase order, and then connected to the first frequency AC system. The second output port of the matrix converter system is connected to the second buffer reactor in phase order, and then connected to the second frequency AC system. The first output port of the matrix converter system is connected to the first soft-start branch and then to the first frequency AC system. The second output port of the matrix converter system is connected to the second soft-start branch and then to the second frequency AC system.

2. The matrix converter system as described in claim 1, characterized in that, Also includes: Q second magnetic elements, wherein the j-th second magnetic element includes K j A third port, L j There are four fourth ports, where Q*K j =N, j∈[1, Q], N j M is an integer greater than or equal to 2. j It is an integer greater than or equal to 2; K of the j-th second magnetic element j Each of the third ports is connected in series with the K. j The other end of the aforementioned converter valve bridge arm; The j-th second magnetic element L j Each of the fourth ports is connected to any one of the phases of the first output port, and at least one of the fourth ports is connected to a different phase from the other fourth ports to the first output port.

3. The matrix converter system as described in claim 1, characterized in that, One of the first soft-start branch and the second soft-start branch includes a charging switch, a charging resistor, and a bypass switch, and the other soft-start branch includes an isolating switch; or Both the first soft-start branch and the second soft-start branch include the charging switch, the charging resistor, and the bypass switch; Wherein, the charging switch is connected in series with the charging resistor, and the bypass switch is connected in parallel with the charging resistor; or The bypass switch is connected in parallel with the branch of the charging switch and the charging resistor that are connected in series.

4. The matrix converter system as described in claim 2, characterized in that, The first magnetic element and the second magnetic element include: Coupled inductors consist of two or more windings, with any one winding constituting a phase; or A two-winding transformer includes a primary winding and a secondary winding, wherein: one end of the primary winding and one end of the secondary winding are in one phase, and the other end of the primary winding and the other end of the secondary winding are in another phase; or A multiphase transformer includes a primary winding and a secondary winding, wherein the primary winding and the secondary winding of the multiphase transformer are connected in a star or delta configuration, and the terminals led out from the corresponding phase windings constitute one phase.

5. The matrix converter system as described in claim 4, characterized in that: The multiphase transformer adopts the star connection method, and the grounding method includes: direct grounding, grounding through the target coil, grounding through the target resistor, or no grounding; or The multiphase transformer adopts a delta connection method, and the grounding methods include: grounding through a Z-type transformer, grounding after three reactors, or no grounding.

6. The matrix converter system as described in claim 1, characterized in that, The converter valve bridge arm includes n sub-modules connected in series, where n is a positive integer; wherein, each sub-module includes a full-bridge circuit, and each sub-module is connected in series through an AC port.

7. A control method for a matrix converter system according to any one of claims 1-6, characterized in that, The control method includes: Start from the first frequency AC system or start from the second frequency AC system.

8. The control method as described in claim 7, characterized in that, One of the first soft-start branch and the second soft-start branch includes a charging switch, a charging resistor, and a bypass switch, and the other soft-start branch includes an isolating switch, or both include the charging switch, the charging resistor, and the bypass switch. The starting from the first frequency AC system includes: If the first soft starter branch or the second soft starter branch includes a disconnect switch, close the disconnect switch; Close the charging switch of the first soft starter branch; In response to the completion of charging of the converter valve bridge arm, the bypass switch of the first soft start branch is closed; Unlock the converter valve bridge arm; Close the charging switch of the second soft starter branch and close the bypass switch of the second soft starter branch.

9. The control method as described in claim 7, characterized in that, One of the first soft-start branch and the second soft-start branch includes a charging switch, a charging resistor, and a bypass switch, and the other soft-start branch includes an isolating switch, or both include the charging switch, the charging resistor, and the bypass switch. The starting from the second frequency AC system includes: If the second soft starter branch or the first soft starter branch includes a disconnect switch, close the disconnect switch; Close the charging switch of the second soft start branch; In response to the completion of charging of the converter valve bridge arm, the bypass switch of the second soft start branch is closed; Unlock the converter valve bridge arm; Close the charging switch of the first soft starter branch and close the bypass switch of the first soft starter branch.

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