A method and apparatus for fusion control of a converter

Abstract

This invention provides a fusion control method and apparatus for a converter, belonging to the field of power electronic control technology. The method includes: calculating the initial operating short-circuit ratio of the converter under a single grid-connected control mode and the operating short-circuit ratio after fusion control; obtaining an improvement index for the operating short-circuit ratio by subtracting the two, and setting the improvement index in segments according to the value of the operating short-circuit ratio after fusion control; calculating the fusion coefficient between grid-connected control and grid-connected control based on the improvement index; weighting the modulation signals of the two controls according to the fusion coefficient to obtain the modulation signal of the fusion-controlled converter, and generating the PWM control signal of the converter. The fusion control method for the converter provided by this invention achieves a smooth transition of the converter's operating mode and improves the stability of the system under different grid operating conditions.

Description

Technical Field

[0001] This invention relates to the field of power electronic control technology, specifically to a fusion control method and system for a converter. Background Technology

[0002] With the large-scale grid connection of renewable energy, the penetration rate of power electronic devices in the power grid has increased significantly, causing the power system to gradually evolve from being dominated by traditional synchronous generators to being highly electronic, which poses challenges to the stable operation of the power system.

[0003] Currently, there are two main types of grid-connected control methods for power electronic equipment: grid-following (GFL) control technology and grid-connecting (GFM) control technology. GFL control tracks the grid voltage through a phase-locked loop (PLL), offering advantages such as simple control and extensive engineering experience. It can operate stably under strong grid conditions, but it cannot actively support the grid in weak grid conditions, leading to small-signal stability issues. GFM control, on the other hand, simulates the external characteristics of a synchronous generator, actively providing inertia and damping to the grid. It can operate stably under weak grid conditions, but its control complexity is high, and it can experience stability problems in strong grid conditions.

[0004] Due to the complex and variable operating conditions of actual power grids, single converter control is no longer sufficient to meet current grid demands. Therefore, converters with GFL / GFM dual-mode operation capabilities have become an important technological direction for improving system flexibility and stability. However, existing hybrid-mode control strategies typically perform hard switching of converter operating modes based on grid conditions. This switching method usually generates certain disturbances, and in severe cases, may cause oscillations that lead to system instability, making it difficult to guarantee a smooth transition and stable operation of the converter under different grid intensities. Summary of the Invention

[0005] To address the problem that existing technologies can easily cause disturbances or even instability when converters switch between grid-connected and grid-connected modes, this application proposes a converter fusion control method. This method adaptively adjusts the fusion coefficient based on the change in the grid short-circuit ratio, thereby achieving a smooth transition of the converter's operating mode and improving the system's stability under different grid operating conditions.

[0006] In a first aspect, the present invention provides a method for fusion control of a converter, comprising: calculating the initial operating short-circuit ratio of the converter in a single grid-type control mode; calculating the operating short-circuit ratio after fusion control; subtracting the operating short-circuit ratio after fusion control from the initial operating short-circuit ratio to obtain an improvement index for the operating short-circuit ratio, and setting the improvement index in segments according to the value of the operating short-circuit ratio after fusion control; calculating the fusion coefficient of grid-type control and grid-type control of the converter according to the improvement index of the operating short-circuit ratio; weighting the modulation signal of the grid-type control and the modulation signal of the grid-type control according to the fusion coefficient to obtain the modulation signal of the fusion-controlled converter, and generating a PWM control signal of the converter according to the modulation signal of the fusion-controlled converter.

[0007] According to the converter fusion control method provided by the present invention, the initial operating short-circuit ratio satisfies:

[0008] in, OSCR 0 represents the initial short-circuit ratio during operation; It is the per-unit value of the reciprocal of the active power currently output by the converter; B g This is the per-unit value of the grid admittance.

[0009] According to the converter fusion control method provided by the present invention, the operating short-circuit ratio after fusion control satisfies:

[0010] in, OSCR The short-circuit ratio of the system after adopting fusion control; K GFL The fusion coefficient controlled by GFL; K GFM The fusion coefficient is controlled by GFM; S B This refers to the rated capacity of the converter; This is the per-unit admittance value of the small-signal control for a grid-type control under unit capacity.

[0011] According to the converter fusion control method provided by the present invention, the step of segmenting the setting of the improvement index includes: when the operating short-circuit ratio after fusion control is less than a first preset threshold, setting the improvement index to a first improvement index value; when the operating short-circuit ratio after fusion control is greater than or equal to the first preset threshold and less than or equal to a second preset threshold, setting the improvement index to a second improvement index value; and when the operating short-circuit ratio after fusion control is greater than the second preset threshold, setting the improvement index to a third improvement index value.

[0012] According to the converter fusion control method provided by the present invention, the first preset threshold is 3 and the second preset threshold is 10.

[0013] According to the converter fusion control method provided by the present invention, the fusion coefficient of the grid-type control satisfies:

[0014] The fusion coefficient of the network control satisfies:

[0015] in, The fusion coefficient for network-type control. The integration coefficient with the network control. To improve the short-circuit ratio, The initial short-circuit ratio, It is the per-unit value of the reciprocal of the active power currently output by the converter; For the rated capacity of the converter, This is the per-unit admittance value of the small-signal control for a grid-type control under unit capacity.

[0016] According to the converter fusion control method provided by the present invention, the weighting of the modulation signal of the grid-based control and the modulation signal of the network-based control satisfies:

[0017] in, To integrate the modulation signals of the control converter, This is the integration coefficient with the network control. The modulation signal is for the mesh control section; The fusion coefficient for network-type control; This is the modulation signal for the network-type control section.

[0018] Secondly, the present invention also provides a fusion control device for a converter, comprising: The first calculation module is configured to calculate the initial operating short-circuit ratio of the converter in a single-network control mode; The second calculation module is configured to calculate the short-circuit ratio after fusion control is adopted; The improvement index module is configured to calculate the difference between the operating short-circuit ratio after adopting fusion control and the initial operating short-circuit ratio to obtain an improvement index for the operating short-circuit ratio, and to set the improvement index in segments according to the value of the operating short-circuit ratio after adopting fusion control. The fusion coefficient module is configured to calculate the fusion coefficient of converter and grid-type control and grid-type control based on the improvement index of the operating short-circuit ratio; The modulation module is configured to weight the modulation signal of the grid-type control and the modulation signal of the network-type control according to the fusion coefficient to obtain the modulation signal of the fusion control converter, and generate the PWM control signal of the converter according to the modulation signal of the fusion control converter.

[0019] Thirdly, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the fusion control method for any of the converters described above.

[0020] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the fusion control method for the converter as described above.

[0021] The converter fusion control method and apparatus provided by the present invention have the following advantages compared with the prior art: This invention quantifies changes in grid strength by calculating the initial operating short-circuit ratio and the operating short-circuit ratio after fusion control. By introducing an enhancement index for the operating short-circuit ratio and setting it in segments, differentiated adjustment strategies can be adopted according to different grid strength intervals. By establishing a mapping relationship between the enhancement index and the fusion coefficient, adaptive adjustment of control weights for grid-following and grid-building types is achieved. Finally, through weighted modulation signals, smooth fusion of the two control modes is realized. This scheme effectively solves the problems of poor adaptability of a single control mode and disturbances caused by hard mode switching, significantly improving the adaptability of the converter and the system stability under different grid operating conditions. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a control block diagram of a converter grid-connected system provided by the present invention.

[0024] Figure 2 This is a flowchart of the GFL / GFM converter fusion control method.

[0025] Figure 3 This is a waveform diagram of the current and active power output of the converter when the short-circuit ratio varies from 1 to 50. Figure 3 (a) is a graph showing the change in the operating short-circuit ratio. Figure 3 (b) is the output current waveform of the converter. Figure 3 (c) is the waveform of the output active power of the converter.

[0026] Figure 4 This is a waveform diagram of the converter's output active power when the system frequency drops, where... Figure 4 (a) Waveform of the output active power of a grid-connected converter configured with a fixed ratio grid. Figure 4 (b) is a waveform diagram of the active power output of the fusion control converter.

[0027] Figure 5 This is a waveform diagram of the converter's output reactive power when the system voltage drops. Figure 5 (a) A waveform diagram of the reactive power output of a grid-connected converter configured with a fixed-ratio grid structure. Figure 5 (b) is a waveform diagram of the reactive power output of the integrated control converter.

[0028] Figure 6 This is a waveform diagram of the converter's output active power when the system generates power fluctuations. Figure 6 (a) Waveform of the output active power of a grid-connected converter configured with a fixed ratio grid. Figure 6 (b) is a waveform diagram of the active power output of the fusion control converter.

[0029] Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0031] It should be noted that, in the description of the embodiments of the present invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0032] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more.

[0033] The following is combined Figures 1-7 The present invention describes the fusion control method and apparatus for converters provided in the embodiments of the present invention.

[0034] Example 1: This embodiment provides a fusion control method for a converter, applied to a converter system including a grid-following (GFL) control module and a grid-forming (GFM) control module, aiming to solve the problems of poor adaptability of a single control mode and disturbances caused by hard mode switching.

[0035] like Figure 1 As shown, in the system section, the integrated control converter, after filtering, is connected to the grid at the PCC point, and the current injected into the grid is... I HCC In the control section, the converter includes a GFL control module and a GFM control module. The GFL control module generates the synchronization phase through a phase-locked loop. θ GFL Synchronize the grid voltage using the active power reference value from the outer power loop. P GFL and reactive power reference value Q GFL A reference signal for the inner current loop is generated, and then a modulation voltage is generated through the inner current loop. e GFL The GFM control module employs virtual synchronous motor control. In the control section, active power is used... P GFM Generate synchronous phase θ GFM In the circuit section, voltage-current dual closed-loop control is used. I HCC Through filter admittance Y HCC The modulation voltage difference between the two control modes of the converter Δe Generates GFL-controlled current I GFL Current controlled by GFM I GFM Finally, the fusion coefficients of the GFL control section are used. K GFLFusion coefficient with GFM control part K GFM The modulation signals generated by the two are weighted and the output modulation signal of the fusion control converter is obtained.

[0036] like Figure 2 As shown, the specific steps include: Step S100: Calculate the initial operating short-circuit ratio of the converter in single-network control mode.

[0037] Specifically, the initial operating short-circuit ratio This indicator serves as a baseline for characterizing the grid strength before the introduction of grid-based control strategies. During converter startup or initial operation, the system defaults to a single grid-based control mode. At this time, the initial short-circuit ratio is calculated by collecting the current active power output of the converter and the grid admittance parameters. This indicator serves as a benchmark for subsequent evaluation of the fusion control effect, directly reflecting the strength of the current grid environment and providing a quantitative basis for adjusting subsequent control strategies.

[0038] Step S200: Calculate the short-circuit ratio after adopting fusion control.

[0039] Specifically, after introducing a strategy that combines network-based control and grid-following control, the equivalent impedance characteristics of the system change, thus affecting the value of the operating short-circuit ratio. This step aims to quantify the effect of the combined control strategy on improving the system's short-circuit ratio. It should be noted that when calculating the combined operating short-circuit ratio, the formula involves a combination coefficient (such as...). , However, the fusion coefficient has not yet been calculated within the current control cycle. To solve this logical loop problem, this embodiment adopts the idea of ​​"iterative calculation," that is, using the fusion coefficient value calculated in the previous control cycle, or using a preset initial fusion coefficient value (e.g., setting) at system startup. , (Initially set to pure network mode) is substituted into the formula for calculation. This method allows for real-time estimation of the system's short-circuit ratio under the current convergence strategy, providing real-time data support for subsequent adjustments.

[0040] Step S300: The difference between the operating short-circuit ratio after adopting fusion control and the initial operating short-circuit ratio is used to obtain the improvement index of the operating short-circuit ratio, and the improvement index is set in segments according to the value of the operating short-circuit ratio after adopting fusion control.

[0041] Specifically, the improvement index of the operating short-circuit ratio This directly reflects the contribution of the integrated control strategy to improving grid strength. A larger improvement index indicates a more significant enhancement effect of the current integrated strategy on system stability. More importantly, this embodiment does not simply adjust control parameters linearly based on the improvement index, but introduces a "segmented setting" mechanism. This is because grid strength itself has nonlinear characteristics: in a weak grid environment (low operating short-circuit ratio), system stability is extremely sensitive to parameter changes, requiring a large improvement index to quickly enhance support capabilities; while in a strong grid environment (high operating short-circuit ratio), system stability is better, and an excessively large improvement index may lead to wasted control resources or even over-adjustment. Therefore, by dividing the operating short-circuit ratio into different intervals based on the magnitude of the integrated short-circuit ratio, and setting different improvement index values ​​in different intervals, the control strategy can be finely adapted, taking into account both the system's response speed and stability under different operating conditions.

[0042] Step S400: Calculate the fusion coefficient of converter and grid-type control and network-type control based on the improvement index of the operating short-circuit ratio.

[0043] Specifically, the fusion coefficient and This determines the weighting of the two control modes in the final output. This step establishes the mapping relationship between the enhancement index and the fusion coefficient, enabling adaptive adjustment of the control strategy. A larger enhancement index means the system needs stronger network support capabilities, and the calculated network fusion coefficient... The corresponding increase will be made in the network integration coefficient. The corresponding decrease will occur; conversely, the decrease will also occur. This dynamic solution process enables the converter to automatically find the optimal balance between grid-following and grid-connected modes based on the real-time grid conditions, avoiding current surges and system oscillations caused by hard mode switching in traditional technologies.

[0044] Step S500: Based on the fusion coefficient, the modulation signal of the grid-type control and the modulation signal of the network-type control are weighted to obtain the modulation signal of the fusion control converter, and the PWM control signal of the converter is generated based on the modulation signal of the fusion control converter.

[0045] Specifically, such as Figure 1 As shown, the corresponding modulation signal is output by the mesh control module. The network-type control module outputs its corresponding modulation signal. This step uses the fusion coefficients calculated in step S400 to perform a weighted summation of the two modulation signals, generating the final fused modulation signal. The signal is then input to a PWM (Pulse Width Modulation) generator to generate control pulses for driving the power switching devices of the converter. Through this weighted fusion at the signal level, the converter is no longer limited to a single operating mode, but can smoothly transition between two control characteristics. This ensures the fast response advantage of grid-connected control while incorporating the active support capability of grid-connected control for weak grids, significantly improving the converter's adaptability and operational stability under various grid conditions.

[0046] Example 2: Taking the converter initially operating in GFL control mode as an example, firstly, the initial short-circuit ratio of the system is calculated as follows:

[0047] in, OSCR 0 represents the initial short-circuit ratio of the system. P -1 It is the per-unit value of the reciprocal of the active power currently output by the converter; B g This is the per-unit value of the grid admittance.

[0048] After adopting fusion control, the system's short-circuit ratio is improved to:

[0049] in, OSCR The short-circuit ratio of the system after adopting fusion control; K GFL The fusion coefficient controlled by GFL; K GFM The fusion coefficient is controlled by GFM; S B This refers to the rated capacity of the converter; b GFM This represents the per-unit admittance of the small signal controlled by GFM under unit capacity.

[0050] After obtaining the short-circuit ratio of the system using fusion control, the difference between it and the initial short-circuit ratio is used to obtain the improvement index of the short-circuit ratio. Simultaneously, the improvement index of the short-circuit ratio is segmented according to different short-circuit ratios of the system. The calculation method for the improvement index and segmentation of the short-circuit ratio is as follows:

[0051]

[0052] in, ΔOSCR 1 is the indicator for improving the operating short-circuit ratio when the operating short-circuit ratio is less than 3; ΔOSCR 2 is the indicator for improving the operating short-circuit ratio when the operating short-circuit ratio is in the range of 3 to 10; ΔOSCR3 is the indicator for improving the operating short-circuit ratio when the operating short-circuit ratio is greater than 10.

[0053] After obtaining the improvement index of the operating short-circuit ratio, the fusion coefficients of GFL control and GFM control are calculated separately:

[0054] Based on the fusion coefficients and modulation signals of GFL control and GFM control, the final PWM control signal of the fused control converter can be obtained through weighted modulation.

[0055] in, e HCC To integrate the modulation signal of the control converter; e GFL The modulation signal for the GFL control section; e GFM This is the modulation signal for the GFM control section.

[0056] This embodiment compares the converter output power waveforms when using grid-following control with a fixed-ratio grid configuration and when using a fusion control method, demonstrating the superiority of the converter fusion control method proposed in this invention.

[0057] Taking the converter initially operating in GFL control mode as an example, this embodiment sets the initial short-circuit ratio of the system to 50. During the simulation time, this ratio is gradually reduced to 1, resulting in the output current waveform and output active power waveform of the fusion-controlled converter, as shown below. Figure 3 As shown. Among them, Figure 3 (a) is a graph showing the change in the short-circuit ratio during system operation. Figure 3 (b) is the waveform of the converter output current. Figure 3 (c) is the waveform diagram of the active power output of the converter. From Figure 3 (a) and Figure 3 (b) It can be seen that when the grid short-circuit ratio gradually decreases, the converter's output current and output active power remain stable, with only minor fluctuations at the moment of change in the operating short-circuit ratio. This avoids system oscillations caused by the decrease in the short-circuit ratio under a single control mode. This embodiment illustrates that when the grid operating short-circuit ratio fluctuates, the converter fusion control method proposed in this invention can adaptively adjust the fusion coefficients of GFL control and GFM control to maintain stable system operation.

[0058] Taking the converter initially operating in GFL control mode as an example, the initial short-circuit ratio of the system was calculated to be 3. With a simulation time of 20 seconds, a 0.03Hz frequency sag was introduced into the grid frequency. The output active power waveform of the converter under fixed-ratio grid configuration and fusion control mode was obtained, as shown below. Figure 4 As shown, including Figure 4 (a) and Figure 4 (b). From Figure 4 As can be seen in (a), when the grid frequency drops by 0.03Hz, the converter configured with a fixed-ratio grid structure cannot actively provide frequency support to the grid, and its active power drops instantaneously after 15s of increased generation, causing the system to lose stability. When the converter adopts the fusion control method proposed in this invention, since the converter needs to increase active power to provide frequency support to the grid, the system's operating short-circuit ratio decreases. Therefore, the converter adaptively adjusts the fusion coefficient of GFL control and GFM control, increases the proportion of GFM control, actively provides frequency support to the grid, and maintains stable system operation. Figure 4 As shown in (b), this embodiment verifies that the converter fusion control method proposed in this invention can quickly respond to frequency changes in the power grid and actively provide frequency support for the power grid.

[0059] Taking the converter initially operating in GFL control mode as an example, the initial short-circuit ratio of the system was calculated to be 3. With a simulation time of 20 seconds, a 5% voltage drop in the grid was set, and the output reactive power waveform of the converter under fixed-ratio grid configuration and fused control mode was obtained, as shown below. Figure 5 As shown, including Figure 5 (a) and Figure 5 As shown in (b). From Figure 5 (a) and Figure 5 As shown in (b), when the grid voltage drops by 5%, the converter needs to generate additional reactive power to provide voltage support to the grid. The active power output of the converter only experiences a small fluctuation at the moment of the grid voltage drop, and then returns to its original value. Since the system's operating short-circuit ratio is related to the active power output of the converter but not to the reactive power output, the system's operating short-circuit ratio remains essentially unchanged. Both grid configurations with a fixed ratio and converters using a fusion control mode can operate stably. This embodiment demonstrates that the converter fusion control method proposed in this invention has high accuracy in responding to the operating short-circuit ratio and will not misjudge the system's operating short-circuit ratio due to changes in other system conditions.

[0060] Taking the converter initially operating in GFL control mode as an example, the initial short-circuit ratio of the system was calculated to be 3. With a simulation time of 20 seconds, a 15% fluctuation in the converter's output active power was set to simulate the continuous change in the short-circuit ratio. This yielded the converter's output active power under both fixed-ratio grid configuration and fusion control mode. Figure 6 As shown, including Figure 6 (a) and Figure 6 (b). From Figure 6As shown in (a), when the converter's output active power fluctuates by 15%, the converter with a fixed-ratio network configuration cannot suppress this fluctuation. When the converter adopts the fusion control method proposed in this invention, due to the fluctuation in the converter's output active power, the system's operating short-circuit ratio changes continuously. Therefore, the converter adaptively adjusts the fusion coefficient of GFL control and GFM control. When the operating short-circuit ratio decreases, the GFM control ratio is increased; when the operating short-circuit ratio increases, the GFL control ratio is increased. This measure effectively suppresses the fluctuation value of the converter's output active power, such as... Figure 6 As shown in (b), the output active power fluctuation of the converter is limited to within 10%. This embodiment illustrates that the converter fusion control method proposed in this invention can adaptively adjust its fusion coefficient to suppress the output active power fluctuation of the converter when the short-circuit ratio of the system changes continuously.

[0061] This invention, through specific embodiments, illustrates that the proposed GFL / GFM converter fusion control method can adaptively adjust the fusion coefficients of GFL control and GFM control according to the system's operating short-circuit ratio. It enables flexible changes in the converter's operating mode under typical operating conditions such as large variations in the operating short-circuit ratio, system frequency / frequency drops, and continuous changes in the operating short-circuit ratio, thus maintaining stable system operation. These conclusions demonstrate that the proposed GFL / GFM converter fusion control method can improve the adaptability of renewable energy grid-connected converters under different grid operating conditions, illustrating the superiority of the proposed converter fusion control method.

[0062] On the other hand, the present invention also provides a fusion control device for a converter, comprising: The first calculation module is configured to calculate the initial operating short-circuit ratio of the converter in a single-network control mode; The second calculation module is configured to calculate the short-circuit ratio after fusion control is adopted; The improvement index module is configured to calculate the difference between the operating short-circuit ratio after adopting fusion control and the initial operating short-circuit ratio to obtain an improvement index for the operating short-circuit ratio, and to set the improvement index in segments according to the value of the operating short-circuit ratio after adopting fusion control. The fusion coefficient module is configured to calculate the fusion coefficient of converter and grid-type control and grid-type control based on the improvement index of the operating short-circuit ratio; The modulation module is configured to weight the modulation signal of the grid-type control and the modulation signal of the network-type control according to the fusion coefficient to obtain the modulation signal of the fusion control converter, and generate the PWM control signal of the converter according to the modulation signal of the fusion control converter.

[0063] It should be noted that the converter fusion control device provided in this embodiment of the invention can execute the converter fusion control method described in any of the above embodiments during specific operation, which will not be elaborated in this embodiment.

[0064] Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention, such as... Figure 7 As shown, the electronic device may include a processor 710, a communications interface 720, a memory 730, and a communication bus 740. The processor 710, communications interface 720, and memory 730 communicate with each other via the communication bus 740. The processor 710 can call logic instructions from the memory 730 to execute the converter's fusion control method.

[0065] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0066] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the fusion control method of the converter provided in the above embodiments.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fusion control method for a converter, characterized in that, include: Calculate the initial operating short-circuit ratio of the converter under a single-grid control mode; Calculate the short-circuit ratio after adopting fusion control; The difference between the operating short-circuit ratio after adopting fusion control and the initial operating short-circuit ratio is used to obtain the improvement index of the operating short-circuit ratio, and the improvement index is set in segments according to the value of the operating short-circuit ratio after adopting fusion control. Based on the aforementioned short-circuit ratio improvement index, calculate the fusion coefficient of converter and grid-type control and grid-type control; Based on the fusion coefficient, the modulation signal of the grid-type control and the modulation signal of the network-type control are weighted to obtain the modulation signal of the fusion control converter, and the PWM control signal of the converter is generated based on the modulation signal of the fusion control converter.

2. The fusion control method for a converter according to claim 1, characterized in that, The initial operating short-circuit ratio satisfies: in, OSCR 0 represents the initial short-circuit ratio during operation; It is the per-unit value of the reciprocal of the active power currently output by the converter; B g This is the per-unit value of the grid admittance.

3. The fusion control method for a converter according to claim 1, characterized in that, The short-circuit ratio after adopting fusion control satisfies: in, OSCR The short-circuit ratio of the system after adopting fusion control; K GFL The fusion coefficient controlled by GFL; K GFM The fusion coefficient is controlled by GFM; S B This refers to the rated capacity of the converter; This is the per-unit admittance value of the small-signal control for a grid-type control under unit capacity.

4. The fusion control method for a converter according to claim 1, characterized in that, The segmented setting of the improvement indicators includes: When the short-circuit ratio after fusion control is less than the first preset threshold, the improvement index is set to the first improvement index value. When the short-circuit ratio after fusion control is greater than or equal to the first preset threshold and less than or equal to the second preset threshold, the improvement index is set to the second improvement index value. When the short-circuit ratio after fusion control is greater than the second preset threshold, the improvement index is set to the third improvement index value.

5. The fusion control method for a converter according to claim 4, characterized in that, The first preset threshold is 3, and the second preset threshold is 10.

6. The fusion control method for a converter according to claim 1, characterized in that, The fusion coefficients of the network-type control satisfy: The fusion coefficient of the network control satisfies: in, The fusion coefficient for network-type control. The integration coefficient with the network control. To improve the short-circuit ratio, The initial short-circuit ratio, It is the per-unit value of the reciprocal of the active power currently output by the converter; For the rated capacity of the converter, This is the per-unit admittance value of the small-signal control for a grid-type control under unit capacity.

7. The fusion control method for a converter according to claim 1, characterized in that, The weighting of the modulation signal for the mesh control and the modulation signal for the mesh formation control satisfies: in, To integrate the modulation signal of the control converter, This is the fusion coefficient with the network control; The modulation signal is for the mesh control section; The fusion coefficient for network-type control; This is the modulation signal for the network-type control section.

8. A fusion control device for a converter, characterized in that, include: The first calculation module is configured to calculate the initial operating short-circuit ratio of the converter in a single-network control mode; The second calculation module is configured to calculate the short-circuit ratio after fusion control is adopted; The improvement index module is configured to calculate the difference between the operating short-circuit ratio after adopting fusion control and the initial operating short-circuit ratio to obtain an improvement index for the operating short-circuit ratio, and to set the improvement index in segments according to the value of the operating short-circuit ratio after adopting fusion control. The fusion coefficient module is configured to calculate the fusion coefficient of converter and grid-type control and grid-type control based on the improvement index of the operating short-circuit ratio; The modulation module is configured to weight the modulation signal of the grid-type control and the modulation signal of the network-type control according to the fusion coefficient to obtain the modulation signal of the fusion control converter, and generate the PWM control signal of the converter according to the modulation signal of the fusion control converter.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the fusion control method for the converter as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the fusion control method for the converter as described in any one of claims 1 to 7.

Images