Method and apparatus for grid-forming converter control

Abstract

The application discloses a method and device for network-constructed converter control, which comprises the following steps: obtaining actual values of output current and internal potential; if any one of the actual values of the output current and the internal potential is greater than a maximum threshold value, then adding an active ring front feed compensation power link to power outer ring control and reshaping reactive ring key control parameters. The method and device provided by the embodiment of the application can effectively avoid the risk of system saturation instability caused by internal potential limiting or current limiting.

Description

Technical Field

[0001] This invention relates to the field of power electronic converter technology, and more specifically, to a method and apparatus for controlling a grid-type converter. Background Technology

[0002] In recent years, to further explore the potential of power electronic equipment to support the safe and stable operation of new power systems, grid-forming (GFM) control technology, originating from the microgrid field, has once again attracted widespread attention from academia and industry. The core components of grid-forming control technology include two parts: power outer-loop control and inner-loop control. Power outer-loop control aims to autonomously generate internal potential amplitude and phase references, providing a voltage vector reference for inner-loop control. Currently, various power outer-loop control methods have been proposed, including droop control, virtual synchronous machine control, matching control, and virtual oscillator control, to adapt to the differentiated needs of different equipment carriers or application scenarios. Furthermore, regarding the time scale of the power outer loop, numerous studies have explored in depth the small-disturbance oscillation characteristics, transient stability mechanisms, and system strength support characteristics of grid-connected systems with grid-forming equipment. Overall, research on power outer-loop control is relatively mature.

[0003] Currently, most existing studies have not deeply analyzed the impact of voltage and current inner loop control on the transient performance of grid-type converters (GFM-VSC), which can easily lead to GFM-VSC falling into saturation instability mode dominated by current limiting or internal potential limiting. Summary of the Invention

[0004] In view of this, the present invention proposes a method and apparatus for controlling a grid-type converter, which aims to solve one or more of the technical problems mentioned in the background section above.

[0005] In a first aspect, embodiments of the present invention provide a method for controlling a grid-type converter, the method comprising: obtaining the actual values ​​of the output current and the internal potential; if either the actual value of the output current or the internal potential is greater than a maximum threshold, then adding an active power loop feedforward compensation power link to the power outer loop control and reshaping the key control parameters of the reactive power loop.

[0006] Furthermore, the actual value of the output current is obtained in the following manner: ; in, i d , i q These are the instantaneous values ​​of the dq-axis current of the grid-type converter: ; in, U vscThe actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered: ; in, U g This refers to the grid-side voltage amplitude. X L For line inductance, θ For port voltage phase, U N This is the port voltage rating. K Q This is the reactive voltage droop factor. Q N This is the rated reactive power setting value. ρ This indicates the degree of grid-side voltage fault.

[0007] Furthermore, the actual value of the internal potential is obtained in the following manner: ; in, U g This refers to the grid-side voltage amplitude. X L For line inductance, X F For filtering inductors, θ For port voltage phase, U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. ρ This indicates the degree of grid-side voltage fault.

[0008] Furthermore, the additional active power loop feedforward compensation power link to the outer power loop control includes: transferring the active power loop feedforward compensation power... P N =( mU vsc I max –1)× P N The reference power is added to the outer power loop; where, P N This is the rated active power setting value. U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. I max The maximum threshold value for the output current. m This is the proportionality coefficient.

[0009] Furthermore, the key control parameters for reshaping the reactive power loop include: the steady-state reactive power voltage droop coefficient. KQ With port voltage rating U N Replace with the reshaped K Q and U N Among them, the reshaped K Q By I = k 1 I max Substitute the values ​​into the formula for calculating the actual output current to obtain the result; after reshaping U N By K Q = K Q and E = k 2 E max Substitute the values ​​into the formula for calculating the actual value of the internal potential to obtain the result; where... k 1 and k 2 represents the output current capability compensation coefficient and the output internal potential capability compensation coefficient, respectively. I max and E max These are the maximum threshold values ​​for output current and internal potential, respectively.

[0010] Furthermore, the method further includes: if either the actual value of the output current or the internal potential is greater than the maximum threshold, then the output enable signal is changed from 0 to 1 until the actual values ​​of the internal potential and the output current are both less than or equal to the maximum threshold, then the output enable signal is changed from 1 to 0.

[0011] Secondly, embodiments of the present invention also provide a device for controlling a grid-type converter, the device comprising: an acquisition unit for acquiring the actual values ​​of the output current and the internal electromotive force; and a control unit for, if either the actual value of the output current or the internal electromotive force is greater than a maximum threshold, adding an active power loop feedforward compensation power link to the power outer loop control and reshaping the key control parameters of the reactive power loop.

[0012] Furthermore, the actual value of the output current is obtained in the following manner: ; in, i d , i qThese are the instantaneous values ​​of the dq-axis current of the grid-type converter: ; in, U vsc The actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered: ; in, U g This refers to the grid-side voltage amplitude. X L For line inductance, θ For port voltage phase, U N This is the port voltage rating. K Q This is the reactive voltage droop factor. Q N This is the rated reactive power setting value. ρ This indicates the degree of grid-side voltage fault.

[0013] Furthermore, the actual value of the internal potential is obtained in the following manner: ; in, U g This refers to the grid-side voltage amplitude. X L For line inductance, X F For filtering inductors, θ For port voltage phase, U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. ρ This indicates the degree of grid-side voltage fault.

[0014] Furthermore, the additional active power loop feedforward compensation power link to the outer power loop control includes: transferring the active power loop feedforward compensation power... P N =( mU vsc I max –1)× P N The reference power is added to the outer power loop; where, P N This is the rated active power setting value. U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. I max The maximum threshold value for the output current.m This is the proportionality coefficient.

[0015] Furthermore, the key control parameters for reshaping the reactive power loop include: the steady-state reactive power voltage droop coefficient. K Q With port voltage rating U N Replace with the reshaped K Q and U N Among them, the reshaped K Q By I = k 1 I max Substitute the values ​​into the formula for calculating the actual output current to obtain the result; after reshaping U N By K Q = K Q and E = k 2 E max Substitute the values ​​into the formula for calculating the actual value of the internal potential to obtain the result; where... k 1 and k 2 represents the output current capability compensation coefficient and the output internal potential capability compensation coefficient, respectively. I max and E max These are the maximum threshold values ​​for output current and internal potential, respectively.

[0016] Furthermore, the control unit is also configured to: if either the actual value of the output current or the internal potential is greater than the maximum threshold, change the output enable signal from 0 to 1, until the actual values ​​of the internal potential and the output current are both less than or equal to the maximum threshold, and then change the output enable signal from 1 to 0.

[0017] Thirdly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the methods provided in the above embodiments.

[0018] Fourthly, embodiments of the present invention also provide an electronic device, including: a processor; a memory for storing executable instructions of the processor; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the methods provided in the above embodiments.

[0019] The grid-type converter control method and apparatus provided in this invention can effectively avoid the risk of the system falling into saturation instability due to internal potential limitation or current limitation when either the actual value of the output current or the internal potential exceeds the maximum threshold. This is achieved by adding an active power loop feedforward compensation power link to the power outer loop control and reshaping the key control parameters of the reactive power loop. Attached Figure Description

[0020] Figure 1 An exemplary flowchart of a method for controlling a grid-type converter according to an embodiment of the present invention is shown; Figure 2 A schematic diagram illustrating the system topology and control strategy of a grid-type converter according to an embodiment of the present invention is shown; Figure 3 A simplified circuit diagram of a grid-connected converter connected to an equivalent power grid according to an embodiment of the present invention is shown. Figure 4 An embodiment of the present invention is shown. I max A schematic diagram of the unsaturated characteristic operating range of a grid-type converter under different outer loop parameters under constraints; Figure 5 An embodiment of the present invention is shown. E max A schematic diagram of the unsaturated characteristic operating range of a grid-type converter under different outer loop parameters under constraints; Figure 6 A schematic diagram of the control strategy for the additional active power loop feedforward compensation power link to the power outer loop control and the reshaping of key control parameters of the reactive power loop is shown according to an embodiment of the present invention. Figure 7 A schematic diagram of the simulation waveform of the transient output characteristics of a grid converter under uncontrolled trigger internal potential limiting according to an embodiment of the present invention is shown; Figure 8 A schematic diagram of the simulation waveform of the d-axis transient output characteristics of a grid converter under uncontrolled trigger current limiting according to an embodiment of the present invention is shown. Figure 9 A schematic diagram of the simulation waveform of the transient output characteristics of a grid converter under the control of the grid converter control method provided in the above embodiments according to an embodiment of the present invention is shown. Figure 10 A schematic diagram of a grid-type converter control device according to an embodiment of the present invention is shown. Detailed Implementation

[0021] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0022] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0023] Figure 1 An exemplary flowchart of a method for controlling a grid-type converter according to an embodiment of the present invention is shown.

[0024] like Figure 1 As shown, the method includes: Step S101: Obtain the actual values ​​of output current and internal potential.

[0025] Furthermore, the actual value of the output current is obtained as follows: ; in, i d , i q These are the instantaneous values ​​of the dq-axis current of the grid-type converter: ; in, U vsc The actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered: ; in, U g This refers to the grid-side voltage amplitude. X L For line inductance, θ For port voltage phase, U N This is the port voltage rating. K Q This is the reactive voltage droop factor. Q N This is the rated reactive power setting value. ρ This indicates the degree of grid-side voltage fault.

[0026] Furthermore, the actual value of the internal potential is obtained as follows: ; in, U g This refers to the grid-side voltage amplitude. X L For line inductance, X F For filtering inductors, θ For port voltage phase, U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. ρ This indicates the degree of grid-side voltage fault.

[0027] Specifically, Figure 2 A schematic diagram illustrating the system topology and control strategy of a grid-type converter according to an embodiment of the present invention is shown. Figure 2 As shown, u , i These are the port output voltage and current, respectively. P T and Q T Output the active and reactive power of the node; U ref , ω ref , δ These represent the amplitude, frequency, and phase of the outer loop output reference voltage, respectively. u ref This is the outer loop output reference voltage; e The internal potential is given. The control system of the grid-type converter uses the following virtual synchronous power outer loop control: In the formula, P N and Q N These are the rated active and reactive power settings, respectively. J and τ These are the virtual inertia coefficient and the reactive power regulation coefficient, respectively. K P and K Q These are the active frequency and the reactive voltage droop coefficient, respectively. D P This is the virtual damping coefficient; U N and ω N These are the rated AC voltage amplitude and frequency, respectively.

[0028] Figure 3A simplified circuit diagram of a grid-connected converter connected to an equivalent power grid according to an embodiment of the present invention is shown. Figure 3 The circuit structure shown allows us to derive the actual output current amplitude of the grid converter when the saturation stage is not triggered: (1) The output current of the grid-type converter in the dq-axis coordinate system is: (2) In the formula, i d , i q These are the instantaneous values ​​of the dq-axis current of the grid-type converter, respectively. ρ The degree of grid-side voltage fault; Therefore, the actual output current amplitude is: (3) Figure 4 An embodiment of the present invention is shown. I max A schematic diagram showing the unsaturated operating range of a grid-type converter under different outer loop parameters under constraints. (See diagram below.) Figure 4 As shown, the colored area is... I max The operating range of the unsaturated characteristics of the grid-type converter under different outer loop parameters under constraints. K Q When the value is large, as the severity of the fault increases, there exists a power angle operating range where the voltage source characteristics cannot be maintained, meaning it will inevitably enter saturation operation; as... K Q The value decreases during the fault period. I max The virtual power angle margin that a constrained grid-type converter can withstand gradually increases, enabling it to maintain normal operation. Similarly, U N The decrease also increases the unsaturated normal operating range.

[0029] according to Figure 3 The circuit structure shown allows us to derive the internal potential amplitude of the grid-type converter when the saturation stage is not triggered: (4) Figure 5 An embodiment of the present invention is shown. E max A schematic diagram showing the unsaturated operating range of a grid-type converter under different outer loop parameters under constraints. (See diagram below.) Figure 5 As shown, the colored area is... E maxOperating range of unsaturated characteristics of grid-type converters under different outer loop parameters under constraints. Figure 5 In medium-voltage circuits, when the short-circuit ratio is high, the unsaturated normal operating range of the grid-type converter is significantly reduced, and under severe faults, there exists an operating range that inevitably triggers internal potential saturation. Simultaneously, the outer-loop control parameters also significantly affect the internal potential saturation characteristics of the grid-type converter, such as... U N The increase in will also significantly reduce the unsaturated operating range.

[0030] Step S102: If either the actual value of the output current or the internal potential is greater than the maximum threshold, then add the active loop feedforward compensation power link to the power outer loop control and reshape the key control parameters of the reactive loop.

[0031] Furthermore, the method also includes: If either the actual value of the output current or the internal potential is greater than the maximum threshold, the output enable signal will be changed from 0 to 1 until the actual values ​​of the internal potential and the output current are both less than or equal to the maximum threshold, at which point the output enable signal will be changed from 1 to 0.

[0032] Figure 6 A schematic diagram illustrating the control strategy for the additional active power loop feedforward compensation power link to the outer power loop control and the reshaping of key control parameters of the reactive power loop according to an embodiment of the present invention is shown. Figure 6 As shown, the power outer loop control strategy is as follows to avoid the dual constraints of current and internal potential saturation; Furthermore, an additional active power loop feedforward compensation power stage is added to the outer power loop control, including: The active loop feedforward compensation power P N =( mU vsc I max –1)× P N The reference power is added to the outer power loop; where, P N This is the rated active power setting value. U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. I max The maximum threshold value for the output current. m This is the proportionality coefficient.

[0033] Specifically, the active power loop feedforward compensation power is calculated as follows: (5) In the formula, mThis is a proportionality coefficient, which can be set to 0.8 to ensure the existence of a stable equilibrium point while also providing a certain power transmission capability.

[0034] Furthermore, the key control parameters of the reactive power loop are reshaped, including: Steady-state reactive voltage droop factor K Q With port voltage rating U N Replace with the reshaped K Q and U N ; Among them, the reshaped K Q By I = k 1 I max Substitute the values ​​into the formula for calculating the actual output current to obtain the result; after reshaping U N By K Q = K Q and E = k 2 E max Substitute the values ​​into the formula for calculating the actual value of the internal potential to obtain the result; where... k 1 and k 2 represents the output current capability compensation coefficient and the output internal potential capability compensation coefficient, respectively. I max and E max These are the maximum threshold values ​​for output current and internal potential, respectively.

[0035] Specifically, regarding the method for reshaping key parameters of the reactive power loop, k 1 and k 2 represents the output current capability compensation coefficient and the output internal potential capability compensation coefficient of the grid-type converter, respectively, and their parameter ranges are (0,1). k 1 and k 2. The larger the selected value, the closer it is to the output capacity limit of the grid-type converter. Considering both equipment safety and system support requirements, it can be set to 0.8~0.95. Once the grid-type converter operates in the saturation range, even if the energy signal is 1, the steady-state reactive power voltage droop factor will be... K Q With port voltage rating UN Replace with the reshaped K Q and U N ,in K Q The calculation can I = k 1 I max Substitute into formula (3) to obtain the result. U N The calculation can K Q = K Q and E = k 2 E max Substitute the values ​​into formula (4) to obtain the result. If the enable signal is 0, the original parameters are retained unchanged.

[0036] Figure 7 A schematic diagram of the simulation waveform of the transient output characteristics of a grid converter under uncontrolled trigger internal potential limiting according to an embodiment of the present invention is shown. Figure 8 A schematic diagram of the simulated waveform of the d-axis transient output characteristics of a grid converter under uncontrolled trigger current limiting according to an embodiment of the present invention is shown. Figure 7 and Figure 8 As shown, after the internal potential limiting and current limiting are triggered under a large disturbance, even if the fault is cleared, the grid-type converter cannot return to normal operation and falls into a saturated unstable state of internal potential or current limiting.

[0037] Under the same perturbation, Figure 9 A schematic diagram of the simulated transient output characteristics of a grid converter under the control of the grid converter control method provided in the above embodiments according to an embodiment of the present invention is shown. Figure 9 As shown in (a) and (b), after the addition of improved control, during the fault duration, neither the internal potential nor the output current of the grid-type converter operated in saturation. Furthermore, after the fault was cleared, the system quickly returned to steady state. From Figure 9 As shown in (e) and (f), during the disturbance period, both the voltage inner loop control and the current inner loop control meet the negative feedback operating conditions, enabling rapid adjustment of the reference value and the actual value. Figure 9 As shown in (c) and (d), the virtual power angle, output active and reactive power have all recovered to the initial operating state, and the transient stability is achieved.

[0038] In the above embodiments, when either the actual value of the output current or the internal potential exceeds the maximum threshold, by adding an active power loop feedforward to compensate the power loop to the power outer loop control and reshaping the key control parameters of the reactive power loop, the risk of the system falling into saturation instability due to internal potential limiting or current limiting can be effectively avoided.

[0039] Figure 10 A schematic diagram of a grid-type converter control device according to an embodiment of the present invention is shown.

[0040] like Figure 10 As shown, the device includes: Acquisition unit 1001 is used to acquire the actual values ​​of output current and internal potential; The control unit 1002 is used to add active loop feedforward compensation power link to the power outer loop control and reshape the key control parameters of the reactive loop if either the actual value of the output current or the internal potential is greater than the maximum threshold.

[0041] Furthermore, the actual value of the output current is obtained as follows: ; in, i d , i q These are the instantaneous values ​​of the dq-axis current of the grid-type converter: ; in, U vsc The actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered: ; in, U g This refers to the grid-side voltage amplitude. X L For line inductance, θ For port voltage phase, U N This is the port voltage rating. K Q This is the reactive voltage droop factor. Q N This is the rated reactive power setting value. ρ This indicates the degree of grid-side voltage fault.

[0042] Furthermore, the actual value of the internal potential is obtained as follows: ; in, U g This refers to the grid-side voltage amplitude. XL For line inductance, X F For filtering inductors, θ For port voltage phase, U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. ρ This indicates the degree of grid-side voltage fault.

[0043] Furthermore, an additional active power loop feedforward compensation power stage is added to the outer power loop control, including: The active loop feedforward compensation power P N =( mU vsc I max –1)× P N The reference power is added to the outer power loop; where, P N This is the rated active power setting value. U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. I max The maximum threshold value for the output current. m This is the proportionality coefficient.

[0044] Furthermore, the key control parameters of the reactive power loop are reshaped, including: Steady-state reactive voltage droop factor K Q With port voltage rating U N Replace with the reshaped K Q and U N ; Among them, the reshaped K Q By I = k 1 I max Substitute the values ​​into the formula for calculating the actual output current to obtain the result; after reshaping U N By K Q = K Q and E = k 2E max Substitute the values ​​into the formula for calculating the actual value of the internal potential to obtain the result; where... k 1 and k 2 represents the output current capability compensation coefficient and the output internal potential capability compensation coefficient, respectively. I max and E max These are the maximum threshold values ​​for output current and internal potential, respectively.

[0045] Furthermore, the control unit is also used for: If either the actual value of the output current or the internal potential is greater than the maximum threshold, the output enable signal will be changed from 0 to 1 until the actual values ​​of the internal potential and the output current are both less than or equal to the maximum threshold, at which point the output enable signal will be changed from 1 to 0.

[0046] In the above embodiments, when either the actual value of the output current or the internal potential exceeds the maximum threshold, by adding an active power loop feedforward to compensate the power loop to the power outer loop control and reshaping the key control parameters of the reactive power loop, the risk of the system falling into saturation instability due to internal potential limiting or current limiting can be effectively avoided.

[0047] It should be noted that the apparatus provided in the above embodiments is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the apparatus and method embodiments provided in the above embodiments belong to the same concept, and their specific implementation process can be found in the method embodiments, which will not be repeated here.

[0048] This invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the grid-type converter control method provided in the above embodiments.

[0049] This invention also provides an electronic device, including: a processor; a memory for storing processor-executable instructions; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the grid-type converter control method provided in the above embodiments.

[0050] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

[0051] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0052] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0053] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0054] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0055] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0056] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method of meshed grid type converter control, characterized in that, The method includes: Obtain the actual values ​​of output current and internal potential; If either the actual value of the output current or the internal potential exceeds the maximum threshold, then the active power loop feedforward compensation power link is added to the power outer loop control and the key control parameters of the reactive power loop are reshaped.

2. The method of claim 1, wherein, The actual value of the output current is obtained in the following way: ； in, i d , i q These are the instantaneous values ​​of the dq-axis current of the grid-type converter: ； in, U vsc The actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered: ； in, U g This refers to the grid-side voltage amplitude. X L For line inductance, θ For port voltage phase, U N This is the port voltage rating. K Q This is the reactive voltage droop factor. Q N This is the rated reactive power setting value. ρ This indicates the degree of grid-side voltage fault.

3. The method according to claim 2, characterized in that, The actual value of the internal potential is obtained in the following way: ； in, U g This refers to the grid-side voltage amplitude. X L For line inductance, X F For filtering inductors, θ For port voltage phase, U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. ρ This indicates the degree of grid-side voltage fault.

4. The method according to claim 1, characterized in that, The additional active power loop feedforward compensation power link to the power outer loop control includes: The active loop feedforward compensation power P N =( mU vsc I max –1)× P N The reference power is added to the outer power loop; where, P N This is the rated active power setting value. U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. I max The maximum threshold value for the output current. m This is the proportionality coefficient.

5. The method according to claim 3, characterized in that, The key control parameters for reshaping the reactive power loop include: Steady-state reactive voltage droop factor K Q With port voltage rating U N Replace with the reshaped K Q and U N ; Among them, the reshaped K Q By I = k 1 I max Substitute the values ​​into the formula for calculating the actual output current to obtain the result; after reshaping U N By K Q = K Q and E = k 2 E max Substitute the values ​​into the formula for calculating the actual value of the internal potential to obtain the result; where... k 1 and k 2 represents the output current capability compensation coefficient and the output internal potential capability compensation coefficient, respectively. I max and E max These are the maximum threshold values ​​for output current and internal potential, respectively.

6. The method according to claim 1, characterized in that, The method further includes: If either the actual value of the output current or the internal potential is greater than the maximum threshold, the output enable signal will be changed from 0 to 1 until the actual values ​​of the internal potential and the output current are both less than or equal to the maximum threshold, at which point the output enable signal will be changed from 1 to 0.

7. A device for controlling a grid-type converter, characterized in that, The device includes: The acquisition unit is used to acquire the actual values ​​of the output current and internal potential. The control unit is used to add active loop feedforward compensation power link to the power outer loop control and reshape the key control parameters of the reactive loop if either the actual value of the output current or the internal potential is greater than the maximum threshold.

8. The apparatus according to claim 7, characterized in that, The actual value of the output current is obtained in the following way: ； in, i d , i q These are the instantaneous values ​​of the dq-axis current of the grid-type converter: ； in, U vsc The actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered: ； in, U g This refers to the grid-side voltage amplitude. X L For line inductance, θ For port voltage phase, U N This is the port voltage rating. K Q This is the reactive voltage droop factor. Q N This is the rated reactive power setting value. ρ This indicates the degree of grid-side voltage fault.

9. The apparatus according to claim 8, characterized in that, The actual value of the internal potential is obtained in the following way: ； in, U g This refers to the grid-side voltage amplitude. X L For line inductance, X F For filtering inductors, θ For port voltage phase, U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. ρ This indicates the degree of grid-side voltage fault.

10. The apparatus according to claim 7, characterized in that, The additional active power loop feedforward compensation power link to the power outer loop control includes: The active loop feedforward compensation power P N =( mU vsc I max –1)× P N The reference power is added to the outer power loop; where, P N This is the rated active power setting value. U vsc This represents the actual output current amplitude of the grid-connected converter when the saturation circuit is not triggered. I max The maximum threshold value for the output current. m This is the proportionality coefficient.

11. The apparatus according to claim 9, characterized in that, The key control parameters for reshaping the reactive power loop include: Steady-state reactive voltage droop factor K Q With port voltage rating U N Replace with the reshaped K Q and U N ; Among them, the reshaped K Q By I = k 1 I max Substitute the values ​​into the formula for calculating the actual output current to obtain the result; after reshaping U N By K Q = K Q and E = k 2 E max Substitute the values ​​into the formula for calculating the actual value of the internal potential to obtain the result; where... k 1 and k 2 represents the output current capability compensation coefficient and the output internal potential capability compensation coefficient, respectively. I max and E max These are the maximum threshold values ​​for output current and internal potential, respectively.

12. The apparatus according to claim 7, characterized in that, The control unit is also used for: If either the actual value of the output current or the internal potential is greater than the maximum threshold, the output enable signal will be changed from 0 to 1 until the actual values ​​of the internal potential and the output current are both less than or equal to the maximum threshold, at which point the output enable signal will be changed from 1 to 0.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1-6.

14. An electronic device, comprising: processor; Memory used to store the processor's executable instructions; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method according to any one of claims 1-6.

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