Large-scale new energy diode phase shift rectification sending-out topological structure and method

Abstract

The invention discloses a large-scale new energy diode phase-shift rectification sending-out topology structure and method. The method comprises the following steps: determining multiple multiples of a diode phase-shift rectification sending-out topology according to alternating-current side harmonic and direct-current side ripple requirements; the distribution number of phase-shifting parallel transformer groups is determined according to a diode phase-shifting rectification output topology multiple number, and the equivalent reconstruction of the multi-winding phase-shifting characteristic is realized through an equal-difference phase-shifting angle sequence; the phase-shifting angle of each phase-shifting parallel transformer bank is controlled by adopting a winding extension connection mode, and the direct-current sides of all the diode rectification units are connected in series to form a high-voltage output loop; the capacity and voltage parameters of the phase-shifting parallel transformer bank are rated by combining a diode phase-shifting rectification topological structure, the new energy power generation capacity and the voltage class of the alternating current and direct current system. And the engineering application of the low-cost, light-weight and high-reliability topology of diode phase-shifting rectification in a large-scale new energy transmission scene can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of DC transmission of renewable energy power generation, and in particular relates to a large-scale new energy diode phase-shift rectification transmission topology structure and method. Background Art

[0002] High Voltage Direct Current (HVDC) technology has become the preferred solution for large-scale transmission of renewable energy power generation due to its outstanding advantages in large-capacity and long-distance transmission.

[0003] Currently, HVDC converters generally utilize modular multilevel converters (MMCs) as their core topology. However, as the installed capacity and transmission distances of renewable energy generation continue to increase, the size, weight, and cost of MMCs have skyrocketed, severely hindering the achievement of grid parity for renewable energy. Diode rectifier (DR)-based HVDC (DR-HVDC) transmission solutions offer significant advantages in both lightweighting and cost-effectiveness, attracting widespread attention from both academia and industry both domestically and internationally. Limited by the highly nonlinear conduction characteristics of DR, conventional DR-HVDC systems experience significant mid- and low-frequency harmonic distortion on the AC side, requiring the addition of numerous passive filtering and reactive power compensation devices to reduce the system's harmonic content and reactive power, undermining the lightweight and cost-effective technical advantages of DR-HVDC solutions. On this basis, the industry has proposed an HVDC (PSDR-HVDC) transmission scheme based on diode phase-shifted rectification (PSDR). This scheme introduces a multi-winding phase-shifted transformer (PST) to replace conventional converter transformers to create a series multiplex topology. This significantly reduces the harmonic content on the AC side of the system and is expected to reduce or even completely eliminate passive filtering devices, thereby further reducing the size, weight and investment cost of HVDC converter valves. This is of great significance for achieving large-scale development, efficient transmission and affordable access to the grid for renewable energy power generation.

[0004] However, existing PSDR-HVDC transmission system research is based on an idealized multi-winding centralized PST topology. While this topology possesses universal applicability and versatility in theoretical analysis, in practical applications of large-scale renewable energy generation, it struggles to overcome platform space and transportation limitations. Furthermore, the electromagnetic coupling design and insulation manufacturing processes between windings are challenging. These engineering challenges make the existing PSDR transmission topology inadequate for large-scale, long-distance renewable energy generation applications.

[0005] Therefore, it is urgent to break through the engineering limitations of multi-winding PST, study the PSDR topology construction method that adapts to the needs of large-scale new energy base construction, and fully ensure the feasibility of the technical advantages of the PSDR-HVDC transmission solution. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the deficiencies in the above-mentioned prior art and provide a large-scale new energy diode phase-shifted rectifier transmission topology structure and method, which is used to solve the technical problems of the PSDR topology equipment based on multi-winding centralized PST in the existing technology, such as the difficulty in manufacturing and the limited transportation and installation. This is conducive to the engineering application of PSDR, a low-cost, lightweight, and highly reliable topology, in new energy transmission scenarios.

[0007] The present invention adopts the following technical solutions: A large-scale new energy diode phase-shift rectification and transmission method includes the following steps: Determine the multiplicity of the diode phase-shift rectifier output topology based on the AC side harmonic and DC side ripple requirements; The number of distributed phase-shifted parallel transformer groups is determined according to the topological multiplicity of the diode phase-shifted rectifier output, and the equivalent reconstruction of the multi-winding phase-shift characteristics is achieved through the equidistant phase-shift angle sequence. The phase shift angle of each phase-shifting parallel transformer group is controlled by connecting the winding extension, and the DC sides of all diode rectifier units are connected in series to form a high-voltage output circuit; The capacity and voltage parameters of the phase-shifted parallel transformer group are determined by combining the diode phase-shifted rectifier topology, the renewable energy power generation capacity and the AC / DC system voltage level quota.

[0008] Preferably, the multiplexing number of the diode phase-shift rectifier output topology is as follows:

[0009] in, is the multiplicity, is a set of positive integers, is the total harmonic distortion rate of the AC side current, is the maximum AC harmonic allowed in actual system operation. is the DC side voltage ripple factor, is the maximum DC ripple.

[0010] Preferably, the number of distributed phase-shifted parallel transformer groups is determined according to the topology multiplicity of the diode phase-shifted rectifier output, and the equivalent reconstruction of the multi-winding phase-shift characteristics is achieved through an equidistant phase-shift angle sequence, specifically: Assume that the number of secondary windings of each phase-shifted parallel transformer group is n , and get the distribution number ; The phase shift angle corresponding to the diode rectifier unit θ i Construct an arithmetic sequence and determine the common difference Δ of the arithmetic sequence θ The phase shift angle difference between the secondary windings of the phase-shifted parallel transformer group is 60° / n ,when n =2, the phase shift angle sequence is equivalently reconstructed to obtain Δ θ .

[0011] Preferably, the distribution number for:

[0012] in, For the multiplicity.

[0013] Preferably, the tolerance Δ θ for:

[0014] in, , For the 2nd i The phase shift angle corresponding to the group of diode rectifier units, For the 2nd i -1 set of diode rectifier units corresponding to the phase shift angle, For the 2nd i +1 set of diode rectifier units corresponding to the phase shift angle.

[0015] Preferably, the phase shift angle of each phase-shifting parallel transformer group is controlled by connecting the winding extensions, and the DC sides of all diode rectifier units are connected in series to form a high-voltage output circuit, specifically: The secondary winding extended phase shift method or the primary winding extended phase shift method is used to respectively perform extended phase shift; The phase-shifting winding of the phase-shifting parallel transformer group adopts two symmetrical extension forms, namely reverse extension and forward extension, to achieve the control of the phase-shifting angle.

[0016] Preferably, when the secondary winding extended phase shift method is adopted, there is N Group PSPT M The secondary windings are extended and phase-shifted, and the phase of the secondary windings satisfies the phase-shift angle sequence; When the primary winding extension phase shift method is adopted, there is N Group PSPT N The primary windings are extended and phase-shifted, and all secondary windings are connected in Y / D type to induce the primary electromotive force. At this time, the phase of the secondary winding meets the phase shift angle sequence.

[0017] Preferably, the phase-shifting parallel transformer group adopts a symmetrical arrangement to reduce the design cost of the equipment. In this case, the first term of the phase-shifting angle sequence is θ 1 is the reverse phase shift angle, which is as follows:

[0018] in, For the multiplicity.

[0019] Preferably, when the secondary winding of the PSPT is in phase shift mode, the output composite voltage is U o = U s When PSPT adopts the primary winding extension phase shift mode, the output composite voltage U o = U p ; Based on the output composite voltage, the voltage rating of the initial and extension windings is:

[0020] in, is the initial winding voltage of the phase shift, is the phase shift angle, is the phase-shifted extended winding voltage.

[0021] In a second aspect, an embodiment of the present invention provides a diode phase-shifted rectifier transmission topology for a new energy power generation base, comprising a phase-shifted parallel transformer group and a diode rectifier unit, wherein the primary windings of the phase-shifted parallel transformer group are connected in parallel to an AC busbar, and the secondary windings are respectively connected to the diode rectifier units, and the DC sides of the diode rectifier units are sequentially connected in series in a phase-shifted angle sequence; For the secondary winding extended phase shift mode, the primary winding adopts Y-type connection mode, and the secondary winding adopts D-type extended phase shift connection mode, with a total of N Phase-shifted parallel transformer group M The secondary windings are extended and phase-shifted, and the phase of the secondary windings satisfies the phase-shift angle sequence; For the primary winding extended phase shift mode, the primary winding adopts the d-type extended phase shift connection type, and the secondary winding adopts the Y / d-type connection to induce the primary electromotive force. N Phase-shifted parallel transformer group N The primary windings are extended and phase-shifted, and the phase of the secondary winding satisfies the phase-shift angle sequence.

[0022] In a third aspect, a computer device includes 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 above-mentioned large-scale new energy diode phase-shift rectification and transmission method are implemented.

[0023] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, comprising a computer program, which, when executed by a processor, implements the steps of the above-mentioned large-scale new energy diode phase-shift rectification and transmission method.

[0024] In a fifth aspect, a chip 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 above-mentioned large-scale new energy diode phase-shift rectification and transmission method are implemented.

[0025] In a sixth aspect, an embodiment of the present invention provides an electronic device, comprising a computer program, which, when executed by the electronic device, implements the steps of the above-mentioned large-scale new energy diode phase-shift rectification and transmission method.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects: A large-scale new energy diode phase-shifted rectification and transmission method is proposed. This method uses phase-shifted parallel transformers (PSPTs) to construct a PSDR transmission topology for a new energy power generation base. Compared to multi-winding centralized PSTs, the PSPT structure can reduce the rated capacity and voltage level of individual transformers while ensuring safe insulation gaps between windings, thereby reducing the difficulty of equipment design, manufacturing, transportation, and installation. Furthermore, each group of PSPTs has a specific phase-shift angle, which gives the PSDR transmission topology multiple external characteristics while effectively reducing harmonic distortion within the transformer itself, thereby ensuring stable and reliable operating conditions for the entire new energy power generation transmission system.

[0027] Furthermore, by increasing the number of multiplexes in the rectifier topology and utilizing the phase superposition effect of phase-shifting technology, the harmonics on the AC side and the ripple on the DC side can be reduced; the multiplexed phase-shifting rectification can offset harmonics of a specific order by superimposing different phase angles, thereby reducing harmonic pollution to the power grid; the output superposition of multiple rectifier units on the DC side can smooth the DC voltage pulsation and reduce the impact on energy storage equipment or inverters; and the grid's mandatory standards for harmonic distortion rate and DC ripple coefficient can be met, avoiding grid connection restrictions due to excessive harmonics.

[0028] Furthermore, according to the multiplicity of the rectifier topology, a corresponding number of phase-shifting transformer groups are configured, and an equivalent phase-shifting characteristic is achieved through an equidistant phase-shifting angle sequence; the equidistant phase-shifting angle sequence ensures that the output phase of each rectifier unit is evenly distributed, maximizing the harmonic cancellation effect; by replacing the complex physical phase-shifting structure with mathematical equivalents, the complexity of transformer design is reduced; by increasing or decreasing the number of parallel transformer groups, it can flexibly adapt to different capacity and voltage level requirements.

[0029] Furthermore, the extended-side connection method of the transformer winding is adopted to accurately control the phase shift angle, and the DC output of each rectifier unit is connected in series to form a high-voltage circuit; the extended-side connection achieves precise phase shift angle adjustment by adjusting the ratio of the number of winding turns to avoid phase error accumulation; the DC side is connected in series and superimposed on the voltage of each unit, so that high DC voltage output can be achieved without additional boosting equipment, reducing equipment costs; the failure of a single rectifier unit in the series structure only affects part of the voltage, and the system can still operate at a reduced rating, thereby improving fault tolerance.

[0030] Furthermore, by combining the diode rectifier topology, renewable energy power generation capacity and AC / DC voltage levels, the capacity and voltage parameters of the phase-shifting transformer group are optimized; ensuring that the transformer capacity matches the renewable energy power generation output to avoid capacity waste or overload risks; reducing transformer manufacturing costs through reasonable allocation of voltage levels and capacities; unifying the AC / DC side voltage parameters to simplify the design of subsequent converters and grid-connected equipment.

[0031] It can be understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0032] In summary, the present invention significantly suppresses harmonics and DC ripple, reducing filtering costs through multiple phase-shift rectification and transformer differential phase-shift reconstruction; DC series connection realizes high-voltage direct transmission, eliminating the need for boosting equipment; the modular design takes into account flexible expansion and high fault tolerance, adapts to long-distance power transmission of wind, solar and storage bases, and is efficient, economical and reliable.

[0033] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0035] Figure 1 is a flow chart of the method of the present invention; Figure 2 This is the basic structure diagram of PSPT; Figure 3 The PSDR output topology diagram shows that (a) is the secondary winding extended phase shift, and (b) is the primary winding extended phase shift. Figure 4 This is the structure diagram of PSPT phase-shift winding; Figure 5 Schematic diagram of the topological harmonic emission process for PSDR; Figure 6 Schematic diagram of the commutation process of the DR unit of the PSDR output topology; Figure 7 Send out the harmonic characteristic curve of the topology for PSDR; Figure 8 Send reactive characteristic curve of PSDR topology; Figure 9 Send the AC voltage / current waveform of the topology to PSDR; Figure 10 Output topology AC current harmonic spectrum for PSDR; Figure 11 Send active / reactive power waveforms of the topology to PSDR; Figure 12 The internal current waveform and harmonic spectrum of the PSPT, where (a) is before the phase shift angle sequence is reconstructed, and (b) is after the phase shift angle sequence is reconstructed; Figure 13 This is the overall structure and control scheme diagram of the deep-sea wind power PSDR transmission system; Figure 14 This is the active / reactive power waveform diagram of the deep-sea wind power PSDR transmission system; Figure 15 The AC voltage / current waveform of the deep-sea wind power PSDR transmission system, where (a) is the PSDR side and (b) is the wind turbine side; Figure 16 This is the AC current harmonic spectrum of the deep-sea wind power PSDR transmission system, where (a) is the PSDR side and (b) is the wind turbine side; Figure 17 A schematic diagram of a computer device provided in accordance with an embodiment of the present invention; Figure 18 The present invention is a block diagram of an electronic device according to an embodiment of the present invention.

[0036] Among them, 60. Computer device; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access memory unit; 6202. Cache memory unit; 6203. Read-only memory unit; 6204. Program / Utility; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] The present invention provides a large-scale new energy diode phase-shift rectifier transmission topology and method. The method determines the multiplexing multiplicity of the PSDR transmission topology based on AC-side harmonic and DC-side ripple requirements. The method also determines the number of PSPTs distributed based on the PSDR transmission topology multiplicity, and achieves equivalent reconstruction of multi-winding phase-shift characteristics through an equidistant phase-shift angle sequence. The method controls the phase-shift angle of each PSPT by connecting the winding extensions, and connects the DC sides of all DR units in series to form a high-voltage output circuit. The method combines the PSDR topology, new energy generation capacity, and the AC / DC system voltage ratings of the PSPT capacity and voltage parameters. Compared to PSDR transmission topologies using multi-winding centralized PSTs, the method of the present invention has the advantage of reconstructing the PSDR transmission topology through PSPTs to achieve completely consistent multiplexing characteristics. This method also reduces the design and manufacturing difficulty of transformer equipment and facilitates transportation and installation, facilitating the engineering application of PSDR-HVDC transmission solutions for new energy power generation bases.

[0045] Example 1 See also Figure 1 The present invention provides a large-scale new energy diode phase-shift rectification transmission topology structure and method, including the following steps: S1. Determine the multiplexing number of the PSDR output topology based on the AC side harmonics and DC side ripple requirements; Let the multiplicity be M , the total harmonic distortion (THD) of the AC side current is THD i , the DC side voltage ripple factor is , then the following relationship exists between the above physical quantities:

[0046]

[0047] Consider the maximum AC harmonics allowed in actual system operation THD max and maximum DC ripple λ max Value, PSDR output topology without filtering device multiplierM The following constraints should be met:

[0048] The multiplexing multiplicity of the PSDR output topology is determined by the above formula.

[0049] S2. Determine the number of PSPT distributions based on the topological multiplicity of PSDR output, and achieve equivalent reconstruction of multi-winding phase shift characteristics through an equidistant phase shift angle sequence; S201, suppose the number of secondary windings of each PSPT is n , then its distribution quantity is:

[0050] Preferably, considering that the current equipment manufacturing process of the double secondary winding PSPT is relatively mature, the present invention adopts n =2 for analysis. It should be emphasized that the structure of PSPT may vary with n The value of varies, but the PSDR sending topology construction method based on PSPT is within the scope of protection of the present invention. The basic structure of PSPT is as follows Figure 2 As shown; S202, will Figure 2 Phase shift angle corresponding to the DR unit θ i Constructed as an arithmetic sequence, the common difference Δ of the arithmetic sequence θ for:

[0051] In order to eliminate the low-order harmonic distortion inside the transformer, the phase shift angle difference between the secondary windings of the PSPT is required to be 60° / n ,when n =2, and the equivalent reconstruction of the phase shift angle sequence is obtained:

[0052] S3, use the winding extension connection method to control the phase shift angle of each PSPT, and connect the DC side of all DR units in series to form a high-voltage output circuit, such as Figure 3 shown.

[0053] S301. The present invention provides two PSDR transmission topology construction methods, and the two topology construction methods have the same phase shift effect; Please refer to Figure 3 , a new energy power generation base diode phase shift rectification transmission topology structure includes: The primary windings of each PSPT are connected in parallel to the AC busbar, and the secondary windings are connected to the DR units respectively, and the DC sides of the DR units are connected in series in the order of the phase shift angle sequence. Figure 3 (a) shows the secondary winding extended phase shift mode, the primary winding uniformly adopts the Y-type connection type, and the secondary winding adopts the D-type extended phase shift connection type; Figure 3 (b) shows the primary winding extended phase shifting method, in which the primary windings respectively adopt the d-type extended phase shifting connection type, and the secondary windings uniformly adopt the Y / d-type connection type.

[0054] When using Figure 3 When the secondary winding is extended and phase shifted as shown in (a), there are N Group PSPT M The secondary windings are extended and phase-shifted, and the phase of the secondary windings satisfies the phase-shift angle sequence; When using Figure 3 (b) When the primary winding is extended and phase shifted, there are N Group PSPT N The primary windings are extended and phase-shifted, and all secondary windings adopt a unified Y / d-type connection to induce the primary electromotive force. At this time, the phase of the secondary winding also satisfies the phase shift angle sequence.

[0055] Preferably, the use of a primary winding extended phase-shifting structure can reduce the number of phase-shifting windings and reduce the design and manufacturing difficulty of the PSPT, and the use of a Y / d-type connection on the secondary side can more accurately control the phase-shifting angle difference to 30°, which can reduce the phase-shifting angle error caused by manufacturing precision.

[0056] S302, PSPT phase-shift winding can adopt two symmetrical extension forms, namely reverse extension and forward extension, so as to realize the control of phase-shift angle. The structure of PSPT phase-shift winding is as follows: Figure 4 As shown in the figure, A0-B0-C0 represents the three-phase initial winding, A1-B1-C1 and A2-B2-C2 represent the three-phase composite winding after reverse and forward phase shifting respectively. U 0. U 1. U 2 represent the initial voltage, reverse composite voltage, and forward composite voltage respectively. θ - and θ + They are respectively the reverse and forward phase shift angles, and are defined in the present invention as θ - <0, θ + >0.

[0057] Preferably, the PSPT is arranged symmetrically to reduce the design cost of the equipment. In this case, the first term of the phase shift angle sequence is θ 1 is the reverse phase shift angle, which is:

[0058] S4. Combine the PSDR topology, renewable energy generation capacity and AC / DC system voltage level to determine the capacity and voltage parameters of the PSPT.

[0059] Assume that the total power generation capacity of the new energy power generation base is S t , the rated voltage of the AC collection system is U c , the rated voltage of the DC transmission system is U d , then the rated capacity of a single PSPT is S PSPT for:

[0060] PSPT primary winding voltage U p According to the AC collection system voltage rating, the secondary winding voltage U s The DC output system voltage rating is:

[0061] When the secondary winding of PSPT is in phase shift mode, the output composite voltage U o = U s ; When PSPT adopts the primary winding extended phase shift method, the output composite voltage U o = U p .

[0062] The voltage rating of the initial and extended windings is determined by the output composite voltage, namely:

[0063] Those skilled in the art will appreciate that various aspects of the present invention may be implemented as systems, methods, or program products. Accordingly, various aspects of the present invention may be implemented in the following forms: entirely in hardware, entirely in software (including firmware, microcode, etc.), or in a combination of hardware and software, collectively referred to herein as "circuits," "modules," or "platforms."

[0064] Example 2 The present invention provides a terminal device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of a large-scale new energy diode phase-shift rectification and transmission method, including: The multiplicity of the diode phase-shift rectifier transmission topology is determined according to the AC side harmonic and DC side ripple requirements; the distributed number of phase-shift parallel transformer groups is determined according to the diode phase-shift rectifier transmission topology multiplicity, and the equivalent reconstruction of the multi-winding phase-shift characteristics is achieved through an equidistant phase-shift angle sequence; the phase-shift angle of each phase-shift parallel transformer group is controlled by connecting the winding extensions, and the DC sides of all diode rectifier units are connected in series to form a high-voltage output circuit; the capacity and voltage parameters of the phase-shift parallel transformer group are determined in combination with the diode phase-shift rectifier topology, the new energy power generation capacity and the AC / DC system voltage level quota.

[0065] See also Figure 17 The terminal device is a computer device. The computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable by the processor 61. When executed by the processor 61, the computer program 63 implements the large-scale new energy diode phase-shifted rectification and transmission method of the embodiment. To avoid repetition, the details are not described here. Alternatively, when executed by the processor 61, the computer program 63 implements the functions of each model / unit in the diode phase-shifted rectification and transmission topology construction system for a new energy power generation base of the embodiment. To avoid repetition, the details are not described here.

[0066] The computer device 60 may be a desktop computer, a notebook computer, a PDA, a cloud server, or other computing devices. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. It will be understood by those skilled in the art that Figure 17 This is merely an example of the computer device 60 and does not constitute a limitation of the computer device 60 . The computer device 60 may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0067] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, a graphics processing unit (GPU), a tensor processing unit (TPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0068] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the computer device 60.

[0069] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is about to be output.

[0070] See also Figure 18 The terminal device is an electronic device 600, which is implemented as a general-purpose computing device. The components of the electronic device may include, but are not limited to, at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), and a display unit 640.

[0071] The storage unit stores program codes, which can be executed by the processing unit 610, so that the processing unit 610 performs the steps according to various exemplary embodiments of the present invention described in the above method section of this specification. For example, the processing unit 610 can perform the following steps: Figure 1 Follow the steps shown in .

[0072] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0073] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0074] Bus 630 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0075] The electronic device 600 may also communicate with one or more external devices 700 (e.g., a keyboard, a pointing device, a Bluetooth device, etc.), one or more devices that enable a user to interact with the electronic device 600, and / or any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., a router, a modem). Such communication may occur via an input / output interface 650. Furthermore, the electronic device 600 may also communicate with one or more networks (e.g., a local area network, a wide area network, and / or a public network, such as the Internet) via a network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 via a bus 630. It should be understood that, although not shown in the figures, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0076] Example 3 The present invention also provides a storage medium, specifically a computer-readable storage medium. The computer-readable storage medium is a memory device in a terminal device, used to store programs and data. It is understood that the computer-readable storage medium herein may include both the built-in storage medium in the terminal device and, of course, the extended storage medium supported by the terminal device. It may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for being loaded and executed by a processor. These instructions may be one or more computer programs (including program code). It should be noted that more specific examples of the computer-readable storage medium herein include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0077] Computer-readable storage media also include data signals propagated in baseband or as part of a carrier wave, which carry readable program code. Such propagated data signals can take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable storage medium can also be any readable medium other than a readable storage medium, which can send, propagate, or transmit programs for use by or in conjunction with an instruction execution system, device, or device. The program code contained on the readable storage medium can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, radio frequency, etc., or any suitable combination of the above.

[0078] The program code for performing the operations of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages such as Java, C++, and the like, as well as conventional procedural programming languages such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a stand-alone software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device via any type of network, including a local area network or a wide area network, or may be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0079] The processor may load and execute one or more instructions stored in a computer-readable storage medium to implement the corresponding steps of the large-scale new energy diode phase-shifted rectification and transmission method in the above embodiment; the processor may load and execute the following steps: The multiplicity of the diode phase-shift rectifier transmission topology is determined according to the AC side harmonic and DC side ripple requirements; the distributed number of phase-shift parallel transformer groups is determined according to the diode phase-shift rectifier transmission topology multiplicity, and the equivalent reconstruction of the multi-winding phase-shift characteristics is achieved through an equidistant phase-shift angle sequence; the phase-shift angle of each phase-shift parallel transformer group is controlled by connecting the winding extensions, and the DC sides of all diode rectifier units are connected in series to form a high-voltage output circuit; the capacity and voltage parameters of the phase-shift parallel transformer group are determined in combination with the diode phase-shift rectifier topology, the new energy power generation capacity and the AC / DC system voltage level quota.

[0080] The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.

[0081] 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.

[0082] The PSDR transmission topology of the new energy power generation base constructed based on the present invention is the same as the PSDR transmission topology based on the multi-winding centralized PST in terms of operating principle and external characteristics. The AC system has the advantages of low harmonic distortion and high power factor operation without a filtering device.

[0083] In terms of harmonic characteristics, the harmonic emission process of the PSDR transmission topology of the new energy power generation base constructed by the present invention is as follows: Figure 5 According to the harmonic emission process, the total harmonic current of the PSDR output topology is i hIt can be generally expressed by the following formula:

[0084] in, Z L is the equivalent load factor, which is affected by both the HVDC line and the receiving converter station. When the renewable energy transmission system is in steady state operation, the DC transmission system has a constant voltage and current. Z L can be considered as a constant coefficient.

[0085] Substituting the equidistant phase shift angle sequence constructed in step S2 of the present invention into the above formula, the non-characteristic coupled subharmonic current component is eliminated, and the above formula is simplified to:

[0086] As can be seen from the above formula, as the multiplicity of the PSDR output topology increases, the total harmonic current i h The smaller it is, the lower the harmonic distortion of the AC system is, and the higher the distribution frequency band of the characteristic coupled harmonics is, which can completely eliminate the need for passive filtering devices.

[0087] In terms of reactive power characteristics, the generation of reactive power from the PSDR topology of the new energy power generation base constructed by the present invention is mainly dominated by the commutation process of the DR unit. Taking the voltage and current waveforms of phase A as an example for analysis, the process is as follows: Figure 6 As shown in the figure, u A 、 i A Indicates the voltage and current of phase A of the AC system, u BC 、 u BA 、 u CA Represents the line voltage between BC, BA and CA phases respectively, u d 、 I d Indicates DC voltage and current, γ represents the commutation overlap angle, which can be calculated as follows:

[0088] in, X γ Indicates the leakage reactance of the PSPT.

[0089] also, i + 、 i - express i A The rising and falling currents are expressed in segments as:

[0090] By performing reactive expansion on the fundamental component, the total reactive power generated by the PSDR transmission topology can be obtained as:

[0091] Substituting the rated voltage in step S4 of the present invention into the above equation, it can be seen that during steady-state operation of the renewable energy transmission system, the reactive power generated by the PSDR transmission topology is primarily affected by the number of PSPT distributions and its own leakage reactance. Since renewable energy power generation bases employing conventional DR transmission topologies also require the deployment of multiple converter transformers, the reactive power generated by the commutation process of the DR units is similar to that of the PSDR transmission topology. However, the PSDR transmission topology eliminates the need for a large number of passive filtering devices, significantly reducing the overall reactive power of the system and providing the advantage of high power factor operation.

[0092] The PSDR transmission topology of the new energy power generation base constructed by the present invention achieves the effect of multiple rectification through PSPT. The above theoretical analysis shows that this topology has the significant advantages of low harmonic distortion and high power factor.

[0093] according to i h The calculation formula can be further used to obtain the THD of the PSDR output topology AC system current, and the curve of its change with the PSDR topology multiplicity is plotted as follows: Figure 7 As shown. It can be seen that as the PSDR topology multiplicity increases, THD i Significantly reduced when M When big enough THD i The corresponding power quality standards are met and passive filtering devices can be completely omitted.

[0094] according to Q The calculation formula can be used to obtain the system reactive power and the number of PSPT distribution and its own leakage reactance X γ The relationship between the changes is as follows Figure 8 As shown in Figure 2, it can be seen that the reactive component of the AC system is positively correlated with the PSPT leakage reactance. X γ When 0.1pu Q Since there is no passive filter device, the AC system power factor is 0.964. At this time, the system reactive component can be balanced only by fan reactive power distribution.

[0095] In addition, the PSDR transmission topology construction method for a new energy power generation base provided by the present invention is characterized in that by equivalently reconstructing the phase shift angle sequence, the low-order characteristic harmonics within each PSPT are eliminated and the THD is reduced, thereby reducing the impact of harmonic current impact on the aging of transformer equipment.

[0096] A PSDR output topology simulation model based on PSPT is built in the MATLAB / Simulink environment according to the parameters in Table 1 to verify the above advantages.

[0097] Table 1 PSDR output topology parameters

[0098] Depend on Figure 9 It can be seen that the voltage and current waveforms of the PSDR transmission topology AC system are highly sinusoidal, and the phase difference between voltage and current is small, which intuitively shows the characteristics of the PSDR transmission topology of low harmonic distortion and high power factor. Figure 10 The spectrum distribution of AC current after Fast Fourier Transform (FFT) and THD calculation results show that the harmonics are mainly distributed in the high frequency band and the content is low ( THD i =0.14%), no additional filtering device is required; Figure 11 This shows that when the system delivers a rated active power of 1.0 pu, it generates 0.258 pu of reactive power. The calculated power factor PF is 0.968, which is close to the theoretical analysis of PF = 0.964.

[0099] Depend on Figure 12 It can be seen that the phase shift angle sequence reconstruction can eliminate the low-frequency characteristic harmonics inside the PSPT and reduce the harmonic content (THD before reconstruction = 21.68%, THD after reconstruction = 6.77%), which is beneficial to improving the operating performance of the PSPT.

[0100] A million-kilowatt deep-sea wind power transmission system is one of the typical application scenarios of large-scale, long-distance renewable energy power generation bases. The present invention implements the topology construction method using a 1000MW deep-sea wind power PSDR transmission system as an example. Figure 13 This paper describes the overall structure and control scheme of a deep-sea wind power system, in which: the machine-side converter of the wind turbine adopts constant voltage control, the grid-side converter adopts a grid-type control strategy, and the offshore AC power grid exhibits voltage source characteristics; the receiving-end converter station adopts a grid-following control strategy with a constant DC bus voltage.

[0101] In particular, the deep sea wind power PSDR transmission topology is constructed using the PSPT provided by the present invention. According to the harmonic requirements of the offshore AC power grid, M =12 and n=2, forming 6 groups of PSDR transmission topologies distributed by PSPT; performing equivalent reconstruction on the phase shift angle sequence according to step S202, and calculating Δ θ =5°; PSPT is constructed by using the primary winding extended phase shift method, and the calculated value in step S302 is obtained. θ 1=-27.5°; finally, according to the capacity and voltage of the rated PSPT in step S4, take S t =1200 MVA, U c =66 kV, U d =500 kV, calculated S PSPT =200 MVA, U p =66 kV, U s =30.85 kV, and take U o = U p =66 kV rated different phase shift angles corresponding to U i and U e .

[0102] According to the PSDR transmission topology construction method provided by the present invention, a 1000MW deep-sea wind power PSDR transmission system simulation model was built in the MATLAB / Simulink environment. The main parameters of the system are shown in Table 2.

[0103] Table 2 Parameters of deep-sea wind power PSDR transmission system

[0104] Assume that the deep-sea wind farm has an independent starting power supply and has been fully started. At 0~1s, the receiving-end converter station establishes the HVDC bus voltage and the wind turbine grid-side converter is locked. At 1s, the wind turbine grid-side converter starts and the wind power is sent out through the PSDR converter station. At this time, the wind turbine power waveform is as follows: Figure 14 As shown in Figure 2, when the active power transmitted is 1000 MW, the reactive power generated by the PSDR transmission topology is 350 MVar, and the power factor of the system is 0.944.

[0105] The voltage / current waveforms of deep sea wind power AC systems are as follows: Figure 15 As shown in the figure, it can be seen that without the installation of filtering devices, the deep sea wind power PSDR transmission system has stable operation capabilities, and the voltage and current waveforms of the AC system have extremely high sinusoidal degree. FFT analysis of the harmonic current can be obtained as follows: Figure 16 The harmonic spectrum shown in the figure shows that the THD of the current on both the PSDR AC side and the wind turbine port side of the deep-sea wind power AC system using the PSDR transmission topology is kept at a very low level.

[0106] In summary, the large-scale new energy diode phase-shifted rectification transmission topology structure and method structure of the present invention have application potential in actual new energy power generation and transmission scenarios. The topology construction method based on PSPT can meet the actual needs of the project. While realizing large-scale new energy low-cost and lightweight transmission, it can achieve low harmonic distortion and high power factor effects that match the flexible direct current transmission system without a filtering device.

[0107] The above content is only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A large-scale new energy diode phase-shift rectification and transmission method, characterized in that: The following steps are involved: Determine the multiplicity of the diode phase-shift rectifier output topology based on the AC side harmonic and DC side ripple requirements; The number of distributed phase-shifted parallel transformer groups is determined according to the topological multiplicity of the diode phase-shifted rectifier output, and the equivalent reconstruction of the multi-winding phase-shift characteristics is achieved through the equidistant phase-shift angle sequence. The phase shift angle of each phase-shifting parallel transformer group is controlled by connecting the winding extension, and the DC sides of all diode rectifier units are connected in series to form a high-voltage output circuit; The capacity and voltage parameters of the phase-shifted parallel transformer group are determined by combining the diode phase-shifted rectifier topology, the renewable energy power generation capacity and the AC / DC system voltage level quota.

2. The large-scale new energy diode phase-shift rectification and transmission method according to claim 1 is characterized in that: The multiplicity of the diode phase-shift rectifier output topology is as follows: in, is the multiplicity, is a set of positive integers, is the total harmonic distortion rate of the AC side current, is the maximum AC harmonic allowed in actual system operation. is the DC side voltage ripple factor, is the maximum DC ripple.

3. The large-scale new energy diode phase-shift rectification and transmission method according to claim 1 is characterized in that: The number of distributed phase-shifted parallel transformer groups is determined according to the topological multiplicity of the diode phase-shifted rectifier output, and the equivalent reconstruction of the multi-winding phase-shift characteristics is achieved through the equidistant phase-shift angle sequence. Specifically, Assume that the number of secondary windings of each phase-shifted parallel transformer group is n , and get the distribution number ; The phase shift angle corresponding to the diode rectifier unit θ i Construct an arithmetic sequence and determine the common difference Δ of the arithmetic sequence θ ; The phase shift angle difference between the secondary windings of the phase-shifted parallel transformer group is 60° / n ,when n =2, the phase shift angle sequence is equivalently reconstructed to obtain Δ θ .

4. The large-scale new energy diode phase-shift rectification and transmission method according to claim 3 is characterized in that: Distribution quantity for: in, For the multiplicity.

5. The large-scale new energy diode phase-shift rectification and transmission method according to claim 3 is characterized in that: Tolerance Δ θ for: in, , For the 2nd i The phase shift angle corresponding to the group of diode rectifier units, For the 2nd i -1 set of diode rectifier units corresponding to the phase shift angle, For the 2nd i +1 set of diode rectifier units corresponding to the phase shift angle.

6. The large-scale new energy diode phase-shift rectification and transmission method according to claim 1 is characterized in that: The winding extension connection method is used to control the phase shift angle of each phase-shifting parallel transformer group, and the DC side of all diode rectifier units are connected in series to form a high-voltage output circuit. Specifically: The secondary winding extended phase shift method or the primary winding extended phase shift method is used to respectively perform extended phase shift; The phase-shifting winding of the phase-shifting parallel transformer group adopts two symmetrical extension forms, namely reverse extension and forward extension, to achieve the control of the phase-shifting angle.

7. The large-scale new energy diode phase-shift rectification and transmission method according to claim 6 is characterized in that: When the secondary winding extended phase shift method is used, there is N Group PSPT M The secondary windings are extended and phase-shifted, and the phase of the secondary windings satisfies the phase-shift angle sequence; When the primary winding extension phase shift method is adopted, there is N Group PSPT N The primary windings are extended and phase-shifted, and all secondary windings are connected in Y / D type to induce the primary electromotive force. At this time, the phase of the secondary winding meets the phase shift angle sequence.

8. The large-scale new energy diode phase-shift rectification and transmission method according to claim 6 is characterized in that: The phase-shifting parallel transformer group adopts a symmetrical arrangement to reduce the design cost of the equipment. In this case, the first item of the phase-shifting angle sequence is θ 1 is the reverse phase shift angle, which is as follows: in, For the multiplicity.

9. The large-scale new energy diode phase-shift rectification and transmission method according to claim 1 is characterized in that: When the secondary winding of PSPT is in phase shift mode, the output composite voltage U o = U s When PSPT adopts the primary winding extension phase shift mode, the output composite voltage U o = U p ; Based on the output composite voltage, the voltage rating of the initial and extension windings is: in, is the initial winding voltage of the phase shift, is the phase shift angle, is the phase-shifted extended winding voltage.

10. A diode phase-shifted rectifier output topology structure for a new energy power generation base, characterized in that: It includes a phase-shifting parallel transformer group and a diode rectifier unit, wherein the primary winding of the phase-shifting parallel transformer group is connected in parallel to the AC bus, and the secondary windings are respectively connected to the diode rectifier units, and the DC sides of the diode rectifier units are sequentially connected in series according to the phase-shifting angle sequence; For the secondary winding extended phase shift mode, the primary winding adopts Y-type connection mode, and the secondary winding adopts D-type extended phase shift connection mode, with a total of N Phase-shifted parallel transformer group M The secondary windings are extended and phase-shifted, and the phase of the secondary windings satisfies the phase-shift angle sequence; For the primary winding extended phase shift mode, the primary winding adopts the d-type extended phase shift connection type, and the secondary winding adopts the Y / d-type connection to induce the primary electromotive force. N Phase-shifted parallel transformer group N The primary windings are extended and phase-shifted, and the phase of the secondary winding satisfies the phase-shift angle sequence.

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