Passive control method of modular multilevel matrix converter and related device

Abstract

The invention discloses a passive control method of a modular multi-level matrix converter and a related device, and the method comprises the steps: 1) constructing a state space expression of an M3C according to a mathematical model of the modular multi-level matrix converter M3C, and obtaining a port controlled Hamiltonian PCH model of the M3C according to the state space expression of the M3C; 2) according to a port controlled Hamiltonian model of the M3C, combining an IDA-PBC theory to build an overall framework of a control strategy; (3) constraint conditions are added under the overall framework of the control strategy, and an IDA-PBC controller with an invariable interconnection structure is obtained; and 4) according to the IDA-PBC controller with the invariable interconnection structure, calculating an injection damping parameter range which enables the system to satisfy large-range asymptotic stability, and according to the injection damping parameter range, carrying out passive control on the modular multilevel matrix converter. According to the method and the related device, good steady-state performance and dynamic performance and relatively high robustness of the system can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of converter station control in a flexible frequency-dividing AC system, and relates to a passive control method and related devices for a modular multi-level matrix converter. Background Art

[0002] As the global natural environment deteriorates and fossil energy becomes increasingly scarce, the research and utilization of renewable energy has become a hot topic of concern to countries around the world. Wind power generation is one of the most mature, largest-scale, and most commercially promising renewable energy generation methods. In the future, offshore wind power will develop in a large-scale, deep-sea direction. How to achieve the collection of electricity from offshore wind farms and the transmission of large-capacity electricity over long distances has become an urgent problem to be solved. As a flexible power electronic device, grid-connected converters play an important role in high-voltage direct current (HVDC) systems, flexible alternating current transmission systems (FACTS), and frequency-fractionated transmission systems (FFTS).

[0003] For traditional grid-connected VSC converters, the typical control method currently is vector control, combining an outer power loop with an inner current loop. However, due to the use of a large number of proportional-integral regulators and the influence of high-gain phase-locked loops, traditional vector control parameters are difficult to tune. This can easily lead to system instability and oscillation in special situations, such as when connected to a weak AC system or when the AC system fails. The use of nonlinear control theory to study the transient stability of the system and optimize control performance remains a topic of further research. Due to its excellent dynamic performance, strong robustness, and global stability, PBC control theory has been widely used in recent years in control fields such as motors, power converters, and flexible transmission systems.

[0004] Based on this background, how to achieve good steady-state performance, dynamic performance and strong robustness of the system has become an important technical issue in this industry. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a passive control method and related devices for a modular multi-level matrix converter, which can achieve good steady-state performance, dynamic performance and strong robustness of the system.

[0006] To achieve the above object, the present invention discloses a passive control method for a modular multi-level matrix converter, comprising:

[0007] 1) constructing a state space expression of the modular multi-level matrix converter M3C according to a mathematical model of the M3C, and obtaining a port-controlled Hamiltonian PCH model of the M3C according to the state space expression of the M3C;

[0008] 2) Based on the M3C port-controlled Hamiltonian model and combined with the IDA-PBC theory, the overall framework of the control strategy is established;

[0009] 3) Adding constraints to the overall framework of the control strategy to obtain an IDA-PBC controller with unchanged interconnection structure;

[0010] 4) Based on the IDA-PBC controller with unchanged interconnection structure, an injection damping parameter range that satisfies the system's wide-range asymptotic stability is calculated, and passive control of the modular multilevel matrix converter is performed based on the injection damping parameter range.

[0011] The passive control method of the modular multi-level matrix converter of the present invention is further improved in that:

[0012] Furthermore, the port-controlled Hamiltonian model of the M3C is expressed as:

[0013]

[0014] Among them, J(x) is the interconnection structure matrix reflecting the internal system, R(x) is the damping matrix reflecting the additional port, g(x) is the input matrix reflecting the system port characteristics, and H(x) is the Hamiltonian function reflecting the energy stored in the system.

[0015] Furthermore, the design goal of the IDA-PBC is to obtain a closed-loop PCH system through static state feedback u=β(x):

[0016]

[0017] Among them, J d (x) is the desired interconnection structure matrix, R d (x) is the desired damping structure matrix, H d (x) is the expected equilibrium x * The expected Hamiltonian matrix has a local minimum at .

[0018] Furthermore, the PCH system is a passive network in which energy storage elements, energy consumption elements and ports are interconnected in an energy conservation manner.

[0019] Furthermore, given J(x,u), R(x), H(x), g(x,u) and the desired stable equilibrium point x * ∈R n , when the function β(x) can be found, J a (x), R a (x) and a vector function K(x) satisfying:

[0020]

[0021] And can meet the following conditions at the same time:

[0022] The structure of the system remains unchanged:

[0023]

[0024] K(x) is the gradient of a scalar, satisfying the integrability condition:

[0025]

[0026] Balance point configuration conditions:

[0027]

[0028] Lyapunov stability conditions:

[0029]

[0030] Then x * The closed-loop system with state feedback u=β(x) is a PCH system.

[0031] Furthermore, under closed-loop dynamics, the maximum set of invariants in the set shown in Equation (8) is equal to {x *};

[0032]

[0033] Then x * is the asymptotically stable equilibrium point of the closed-loop system, and the estimated attraction domain range is given by the maximum bounded level set {x∈R n |H d (x)≤0}.

[0034] Furthermore, when the damping matrix R is injected a When the matrix is ​​symmetrical, the closed-loop system will maintain the interconnection structure unchanged, R a The matrix composed of non-diagonal elements in the matrix is ​​a symmetric matrix.

[0035] Furthermore, x * The condition for the large-scale asymptotically stable equilibrium point of the M3C closed-loop system is R d Zhengding.

[0036] The present invention discloses a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the passive control method of the modular multi-level matrix converter are implemented.

[0037] The present invention discloses a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the steps of the passive control method of the modular multi-level matrix converter are implemented.

[0038] The present invention has the following beneficial effects:

[0039] During operation, the passive control method and related devices for a modular multilevel matrix converter described in the present invention comprehensively incorporate the power transmission characteristics, circulating current effects, and frequency leakage of the M3C into a comprehensive set of mathematical models for design. This overcomes the shortcomings of traditional vector control strategies, such as the difficulty in parameter tuning and the tendency to cause system instability or even oscillation in special circumstances such as connection to a weak AC system or AC system failure. The system achieves excellent steady-state performance, dynamic performance, and strong robustness. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0041] Figure 1 This is the main circuit structure diagram of the M3C converter;

[0042] Figure 2 This is the main circuit structure diagram of M3C in the simulation model;

[0043] Figure 3 The overall framework diagram of the M3C control strategy based on IDA-PBC;

[0044] Figure 4 For the IDA-PBC controller, d0s 、m q0s Structural diagram of

[0045] Figure 5 For the IDA-PBC controller, dds 、m dqs 、m qds 、m qqs Structural diagram of

[0046] Figure 6 This is a simulation diagram of the frequency-divided transmission system based on M3C;

[0047] Figure 7 It is the voltage waveform of the power frequency side;

[0048] Figure 8 It is the current waveform of the power frequency side;

[0049] Figure 9This is the working waveform of the phase-locked loop on the power frequency side;

[0050] Figure 10 This is the working waveform of the phase-locked loop on the frequency division side; DETAILED DESCRIPTION

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0052] In the description of the present invention, it is to be understood that the terms “include” and “comprise” indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0053] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0054] It should be further understood that the term "and / or" as used in the present specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0055] It should be understood that although the terms "first," "second," and "third" may be used to describe preset ranges in embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are merely used to distinguish one preset range from another. For example, without departing from the scope of embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0056] The word "if," as used herein, may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0057] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0058] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments disclosed herein. These figures are not drawn to scale; for clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0059] Example 1

[0060] The passive control method of the modular multi-level matrix converter of the present invention includes:

[0061] 1) constructing a state space expression of the modular multi-level matrix converter M3C according to a mathematical model of the M3C, and obtaining a port-controlled Hamiltonian PCH model of the M3C according to the state space expression of the M3C;

[0062] 2) Based on the M3C port-controlled Hamiltonian model and combined with the IDA-PBC theory, the overall framework of the control strategy is established;

[0063] 3) Adding constraints to the overall framework of the control strategy to obtain an IDA-PBC controller with unchanged interconnection structure;

[0064] 4) Based on the IDA-PBC controller with unchanged interconnection structure, an injection damping parameter range that satisfies the system's wide-range asymptotic stability is calculated, and passive control of the modular multilevel matrix converter is performed based on the injection damping parameter range.

[0065] In this embodiment, the port-controlled Hamiltonian model of the M3C is expressed as:

[0066]

[0067] Among them, J(x) is the interconnection structure matrix reflecting the internal system, R(x) is the damping matrix reflecting the additional port, g(x) is the input matrix reflecting the system port characteristics, and H(x) is the Hamiltonian function reflecting the energy stored in the system.

[0068] In this embodiment, the design goal of the IDA-PBC is to obtain a closed-loop PCH system through static state feedback u=β(x):

[0069]

[0070] Among them, J d (x) is the desired interconnection structure matrix, R d (x) is the desired damping structure matrix, H d (x) is the expected equilibrium x * The expected Hamiltonian matrix has a local minimum at .

[0071] In this embodiment, the PCH system is a passive network in which energy storage elements, energy consumption elements and ports are interconnected in an energy conservation manner.

[0072] In this embodiment, given J(x,u), R(x), H(x), g(x,u) and the desired stable equilibrium point x * ∈R n , when the function β(x) can be found, J a (x), R a (x) and a vector function K(x) satisfying:

[0073]

[0074] And can meet the following conditions at the same time:

[0075] The structure of the system remains unchanged:

[0076]

[0077] K(x) is the gradient of a scalar, satisfying the integrability condition:

[0078]

[0079] Balance point configuration conditions:

[0080]

[0081] Lyapunov stability conditions:

[0082]

[0083] Then x * The closed-loop system with state feedback u=β(x) is a PCH system.

[0084] In this embodiment, under closed-loop dynamics, the maximum set of invariants in the set shown in formula (8) is equal to {x *};

[0085]

[0086] Then x * is the asymptotically stable equilibrium point of the closed-loop system, and the estimated attraction domain range is given by the maximum bounded level set {x∈R n |H d (x)≤0}.

[0087] In this embodiment, when the damping matrix R is injected a When the matrix is ​​symmetrical, the closed-loop system will maintain the interconnection structure unchanged, R a The matrix composed of non-diagonal elements in the matrix is ​​a symmetric matrix.

[0088] In this embodiment, x * The condition for the large-scale asymptotically stable equilibrium point of the M3C closed-loop system is R d Zhengding.

[0089] Example 2

[0090] The passive control method of the modular multi-level matrix converter of the present invention comprises the following steps:

[0091] 1) According to the mathematical model of M3C, a state space expression of M3C is derived, and a port controlled Hamiltonian (PCH) model of M3C is constructed according to the state space expression of M3C;

[0092] The energy storage function of the grid-connected converter system is:

[0093]

[0094] The port controlled Hamiltonian (PCH) model of M3C is obtained, wherein the variables of the port controlled Hamiltonian (PCH) model of M3C are:

[0095] The state variables are:

[0096]

[0097] The input variables are:

[0098] u=[V sd V sq V ld V lq ] T (11)

[0099] The output variables are:

[0100] y=[-i sd_s -i sq_s i ld_l i lq_l ] T (12)

[0101] The energy function is differentiated with respect to the state variable, and we have:

[0102]

[0103] The damping matrix added to the reflection port is:

[0104]

[0105] The input matrix reflecting the system port characteristics is:

[0106]

[0107] 2) Combining the IDA-PBC theory, a passive control strategy for modular multilevel converters in a flexible frequency-divided transmission system is proposed, and the overall framework of the control strategy is established;

[0108] The expression of the IDA-PBC controller of the M3C system is obtained as follows:

[0109]

[0110] 3) Adding constraints to the overall framework of the control strategy to obtain an IDA-PBC controller with unchanged interconnection structure;

[0111] When the injection damping matrix is ​​taken as a symmetric matrix, the closed-loop system will maintain the interconnection structure unchanged. The matrix composed of non-diagonal elements in the matrix must be a symmetric matrix. Let:

[0112]

[0113] It is found that the constraints of each injection damping parameter are:

[0114]

[0115] 4) According to the IDA-PBC theory, the injection damping parameter range that makes the system meet the asymptotic stability in a wide range is calculated;

[0116] So that x * The condition for a large-scale asymptotically stable equilibrium point of a closed-loop system is R d Positive determination, further get:

[0117]

[0118] Example 3

[0119] A computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the passive control method for a modular multilevel matrix converter are implemented. For example, the steps include: 1) constructing a state space expression of the modular multilevel matrix converter M3C based on a mathematical model of the M3C, and obtaining a port-controlled Hamiltonian PCH model of the M3C based on the state space expression of the M3C; 2) constructing an overall framework of a control strategy based on the port-controlled Hamiltonian model of the M3C in combination with the IDA-PBC theory; 3) adding constraints to the overall framework of the control strategy to obtain an IDA-PBC controller with an unchanged interconnection structure; 4) calculating, based on the IDA-PBC controller with an unchanged interconnection structure, an injection damping parameter range that satisfies a wide range of asymptotic stability for the system, and performing passive control of the modular multilevel matrix converter according to the injection damping parameter range. The memory may include internal memory, such as high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus. This internal bus may be an Industry Standard Architecture bus, a Peripheral Component Interconnect Standard bus, an Extended Industry Standard Architecture bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The memory is used to store programs. Specifically, the program may include program code, and the program code includes computer operating instructions. The memory may include internal memory and non-volatile memory, and provides instructions and data to the processor.

[0120] Example 4

[0121] A computer-readable storage medium stores a computer program. When executed by a processor, the computer program implements the steps of the passive control method of the modular multilevel matrix converter, for example, including: 1) constructing a state-space expression of the modular multilevel matrix converter M3C based on a mathematical model of the M3C, and obtaining a port-controlled Hamiltonian PCH model of the M3C based on the state-space expression of the M3C; 2) constructing an overall framework of the control strategy based on the port-controlled Hamiltonian model of the M3C and combining it with the IDA-PBC theory; 3) adding constraints to the overall framework of the control strategy to obtain an IDA-PBC controller with an unchanged interconnection structure; 4) calculating an injection damping parameter range that satisfies a wide range of asymptotic stability for the system based on the IDA-PBC controller with an unchanged interconnection structure, and performing passive control of the modular multilevel matrix converter based on the injection damping parameter range. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include a read-only memory (ROM), a hard disk, a flash memory, an optical disk, a magnetic disk, and the like.

[0122] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0123] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0124] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0125] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0126] Those skilled in the art will readily identify other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0127] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0128] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A passive control method for a modular multi-level matrix converter, characterized in that: include: 1) constructing a state space expression of the modular multi-level matrix converter M3C according to a mathematical model of the M3C, and obtaining a port-controlled Hamiltonian PCH model of the M3C according to the state space expression of the M3C; 2) Based on the M3C port-controlled Hamiltonian model and combined with the IDA-PBC theory, the overall framework of the control strategy is established; 3) Adding constraints to the overall framework of the control strategy to obtain an IDA-PBC controller with unchanged interconnection structure; 4) Based on the IDA-PBC controller with unchanged interconnection structure, an injection damping parameter range that satisfies the system's wide-range asymptotic stability is calculated, and passive control of the modular multilevel matrix converter is performed based on the injection damping parameter range.

2. The passive control method for a modular multi-level matrix converter according to claim 1, wherein: The port-controlled Hamiltonian model of the M3C is expressed as: Among them, J(x) is the interconnection structure matrix reflecting the internal system, R(x) is the damping matrix reflecting the additional port, g(x) is the input matrix reflecting the system port characteristics, and H(x) is the Hamiltonian function reflecting the energy stored in the system.

3. The passive control method for a modular multi-level matrix converter according to claim 1, wherein: The design goal of the IDA-PBC is to obtain a closed-loop PCH system through static state feedback u=β(x): Among them, J d (x) is the desired interconnection structure matrix, R d (x) is the desired damping structure matrix, H d (x) is the expected equilibrium x * The expected Hamiltonian matrix has a local minimum at .

4. The passive control method for a modular multi-level matrix converter according to claim 1, wherein: The PCH system is a passive network consisting of energy storage elements, energy consumption elements and ports interconnected in an energy conservation manner.

5. The passive control method for a modular multi-level matrix converter according to claim 1, wherein: Given J(x,u), R(x), H(x), g(x,u) and the desired stable equilibrium point x * ∈R n , when the function β(x) can be found, J a (x), R a (x) and a vector function K(x) satisfying: And can meet the following conditions at the same time: The structure of the system remains unchanged: K(x) is the gradient of a scalar, satisfying the integrability condition: Balance point configuration conditions: Lyapunov stability conditions: Then x * is the local stable equilibrium point of the closed loop, and the closed loop system with state feedback u=β(x) is a PCH system.

6. The passive control method for a modular multi-level matrix converter according to claim 1, wherein: When the closed-loop dynamics is used, the maximum set of invariants in the set shown in Equation (8) is equal to {x * }; Then x * is the asymptotically stable equilibrium point of the closed-loop system, and the estimated attraction domain range is given by the maximum bounded level set {x∈R n |H d (x)≤0}.

7. The passive control method for a modular multi-level matrix converter according to claim 1, wherein: When the damping matrix R is injected a When the matrix is ​​symmetrical, the closed-loop system will keep the interconnection structure unchanged, R a The matrix composed of non-diagonal elements in the matrix is ​​a symmetric matrix.

8. The passive control method for a modular multi-level matrix converter according to claim 1, wherein: x * The condition for the large-scale asymptotically stable equilibrium point of the M3C closed-loop system is R d Zhengding.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the passive control method for a modular multi-level matrix converter according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the passive control method for a modular multi-level matrix converter according to any one of claims 1 to 8 are implemented.

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