Method, device and apparatus for determining large disturbance instability mode of voltage source converter

Abstract

This invention provides a method, apparatus, and device for determining the large disturbance instability mode of a voltage source converter. The method determines the state of the outer loop control loop within the voltage source converter. If the state indicates that the outer loop control loop is engaged, the instability mode of the voltage source converter is determined using a first preset method. If the state indicates that the outer loop control loop is disengaged, the instability mode of the voltage source converter is determined using a second preset method. The instability modes include current loop instability mode, phase-locked loop instability mode, and outer loop instability mode. By determining the instability mode based on the presence or absence of outer loop control, different instability modes of the voltage source converter can be identified quickly and accurately, providing data support for setting controller parameters and designing control schemes.

Description

Technical Field

[0001] This invention relates to the field of power grid transient stability analysis technology, and in particular to a method, apparatus and equipment for determining the large disturbance instability mode of a voltage source converter. Background Art

[0002] With the increasing penetration rate of renewable energy sources such as wind power and photovoltaics, the continuous commissioning of large-capacity DC projects, and the widespread application of power electronic interface equipment, different instability modes may be triggered. Accurate identification of instability modes is a prerequisite for ensuring the transient stability of new power systems. Voltage source converters (VSCs) have gradually become the main equipment for grid connection of renewable energy.

[0003] Therefore, accurately identifying different instability modes of voltage source converters has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] This invention provides a method, apparatus, and device for determining the large disturbance instability mode of a voltage source converter, which solves the defect in the prior art that it cannot accurately identify the instability mode of a voltage source converter. By accurately determining the instability mode of the voltage source converter, the design of the controller can be guided and modified.

[0005] The present invention provides a method for determining the large disturbance instability mode of a voltage source converter, comprising:

[0006] Determine the state of the outer loop control loop inside the voltage source converter;

[0007] If the state indicates that the outer loop control is engaged, the instability mode of the voltage source converter is determined by the first preset method.

[0008] If the state indicates that the outer loop control loop has exited, the instability mode of the voltage source converter is determined by the second preset method.

[0009] The instability modes include current loop instability mode, phase-locked loop instability mode, and outer loop instability mode.

[0010] According to a method for determining the large disturbance instability mode of a voltage source converter provided by the present invention, the step of determining the instability mode of the voltage source converter by a first preset method includes:

[0011] Determine the first current command value of the d-axis and the first current command value of the q-axis in the grid-connected system where the voltage source converter is located;

[0012] The instability mode of the voltage source converter is determined based on the first current command value of the d-axis and the first current command value of the q-axis.

[0013] According to a method for determining the large disturbance instability mode of a voltage source converter provided by the present invention, the step of determining the instability mode of the voltage source converter based on the first current command value of the d-axis and the first current command value of the q-axis includes:

[0014] If the first current command value of the d-axis and the first current command value of the q-axis are both not equal to the preset value, then the instability mode is determined to be current loop instability.

[0015] If the first current command value of the d-axis and the first current command value of the q-axis are both equal to the preset value, then determine whether the input of the phase-locked loop control loop inside the voltage source converter is equal to the preset value.

[0016] If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability;

[0017] If the input of the phase-locked loop control loop is equal to the preset value, then determine whether the input of the outer loop control loop inside the voltage source converter is equal to the preset value.

[0018] If the input of the outer loop control loop is not equal to the preset value, then the instability mode is determined to be outer loop instability.

[0019] According to a method for determining the large disturbance instability mode of a voltage source converter provided by the present invention, the step of determining the instability mode of the voltage source converter by a second preset method includes:

[0020] Obtain the second current command value of the d-axis and the second current command value of the q-axis in the grid-connected system where the voltage source converter is located;

[0021] The instability mode of the voltage source converter is determined based on the second current command value of the d-axis and the second current command value of the q-axis.

[0022] According to a method for determining the large disturbance instability mode of a voltage source converter provided by the present invention, the step of determining the instability mode of the voltage source converter based on the second current command value of the d-axis and the second current command value of the q-axis includes:

[0023] If the second current command value of the d-axis and the second current command value of the q-axis are both not equal to the preset value, then the instability mode is determined to be current loop instability.

[0024] If both the second current command value of the d-axis and the second current command value of the q-axis are equal to the preset value, then determine whether the input quantity of the phase-locked loop control loop is equal to the preset value.

[0025] If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability.

[0026] According to the method for determining the large disturbance instability mode of a voltage source converter provided by the present invention, the input quantity of the phase-locked loop control loop includes the q-axis component of the AC voltage at the grid connection point of the voltage source converter.

[0027] According to the method for determining the large disturbance instability mode of a voltage source converter provided by the present invention, the input quantity of the outer loop control loop includes the actual value of the DC capacitor voltage of the grid-connected system.

[0028] According to a method for determining the large disturbance instability mode of a voltage source converter provided by the present invention, before determining the state of the outer loop control element inside the voltage source converter, the method further includes:

[0029] The inputs of each control link inside the voltage source converter are obtained based on simulation and waveform recording.

[0030] The present invention also provides a device for determining the large disturbance instability mode of a voltage source converter, comprising:

[0031] The determination module is used to determine the state of the outer loop control loop inside the voltage source converter;

[0032] The determination module is used to determine the instability mode of the voltage source converter by a first preset method if the state indicates that the outer loop control loop is engaged; and to determine the instability mode of the voltage source converter by a second preset method if the state indicates that the outer loop control loop is disengaged; wherein the instability mode includes current loop instability mode, phase-locked loop instability mode and outer loop instability mode.

[0033] The present invention also 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 method for determining the large disturbance instability mode of a voltage source converter as described above.

[0034] 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 method for determining the large disturbance instability mode of a voltage source converter as described above.

[0035] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method for determining the large disturbance instability mode of a voltage source converter as described above.

[0036] This invention provides a method, apparatus, and device for determining the large disturbance instability mode of a voltage source converter. The method determines the state of the outer loop control loop inside the voltage source converter. If the state indicates that the outer loop control loop is engaged, the instability mode of the voltage source converter is determined through a first preset method. If the state indicates that the outer loop control loop is disengaged, the instability mode of the voltage source converter is determined through a second preset method. The instability modes include current loop instability mode, phase-locked loop instability mode, and outer loop instability mode. By determining the instability mode based on the presence or absence of outer loop control, different instability modes of the voltage source converter can be identified quickly and accurately, providing data support for setting controller parameters and designing control schemes. Attached Figure Description

[0037] 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.

[0038] Figure 1 This is one of the flowcharts illustrating the method for determining the large disturbance instability mode of a voltage source converter provided by the present invention;

[0039] Figure 2 This is the second flowchart illustrating the method for determining the large disturbance instability mode of a voltage source converter provided by the present invention.

[0040] Figure 3 This is the third flowchart illustrating the method for determining the large disturbance instability mode of a voltage source converter provided by the present invention.

[0041] Figure 4 This is a schematic diagram of the device for determining the large disturbance instability mode of a voltage source converter provided by the present invention;

[0042] Figure 5 It is a structural schematic diagram of the electronic device provided by the present invention. Detailed Implementation

[0043] 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.

[0044] The following is combined Figures 1-5This invention describes a method, apparatus, and device for determining the large disturbance instability mode of a voltage source converter.

[0045] Figure 1 This is one of the flowcharts illustrating the method for determining the large disturbance instability mode of a voltage source converter provided by the present invention.

[0046] like Figure 1 As shown in the figure, an embodiment of the present invention provides a method for determining the large disturbance instability mode of a voltage source converter, which includes the following steps:

[0047] 101. Determine the state of the outer loop control loop inside the voltage source converter.

[0048] Specifically, before determining the large disturbance instability mode of the voltage source converter, it is first necessary to obtain the inputs of each control loop within the voltage source converter based on simulation and / or waveform recording, namely the proportional-integral (PI) controller inputs of each control loop. Each control loop includes outer loop control (active / reactive power control or DC / AC voltage control), phase-locked loop control, and inner current loop control. It is necessary to determine whether the outer loop control is engaged or disengaged. Different instability mode determination methods are used when the outer loop control is engaged or disengaged. Accurately determining the state of the specific outer loop control loop can better ensure the accuracy of the final instability mode determination.

[0049] 102. If the status indicates that the outer loop control is engaged, the instability mode of the voltage source converter is determined by the first preset method.

[0050] When the outer loop control is determined to be engaged, the instability mode of the voltage source converter is determined using a first preset method. This instability mode includes the current loop instability mode, the phase-locked loop (PLL) instability mode, and the outer loop instability mode. The system instability is determined sequentially for the current loop, the PLL, and the outer loop. These three loops have a logical sequence: the current loop is determined first, then the PLL, and finally the outer loop.

[0051] 103. If the status indicates that the outer loop control loop has exited, the instability mode of the voltage source converter is determined by the second preset method.

[0052] Similarly, when the outer loop control is determined to be inactive, the instability mode of the voltage source converter is determined using the second preset method. That is, it is determined whether the current loop and the phase-locked loop are unstable. First, it is determined whether the current loop is unstable, and then it is determined whether the phase-locked loop is unstable.

[0053] This embodiment provides a method for determining the large disturbance instability mode of a voltage source converter. The method involves determining the state of the outer loop control loop within the voltage source converter. If the state indicates that the outer loop control loop is engaged, the instability mode of the voltage source converter is determined using a first preset method. If the state indicates that the outer loop control loop is disengaged, the instability mode of the voltage source converter is determined using a second preset method. The instability modes include current loop instability mode, phase-locked loop instability mode, and outer loop instability mode. By determining the instability mode based on the presence or absence of outer loop control, the method can quickly and accurately identify different instability modes of the voltage source converter, providing data support for setting controller parameters and designing control schemes.

[0054] Figure 2 This is the second flowchart illustrating the method for determining the large disturbance instability mode of a voltage source converter provided by the present invention.

[0055] like Figure 2 As shown in the figure, this embodiment provides a method for determining the large disturbance instability mode of a voltage source converter, which includes the following steps:

[0056] 201. Determine the state of the outer loop control loop inside the voltage source converter.

[0057] Step 201 has been described in detail in the corresponding step 101 in the above embodiments, so it will not be explained in detail in this embodiment.

[0058] 202. If the status indicates that the outer loop control is engaged, determine the first current command value of the d-axis and the first current command value of the q-axis in the grid-connected system where the voltage source converter is located.

[0059] When the current state indicates that the outer loop control is engaged, the current command values ​​for the d-axis and q-axis are determined by the outer loop control, thus determining the first current command value for the d-axis in the grid-connected system where the voltage source converter is located. and the first current command value of the q-axis Then, based on the first current command value of the d-axis and the first current command value of the q-axis Determine the instability mode of the voltage source converter. Specifically, determine... and The method is as shown in formula (1):

[0060]

[0061] in, This indicates the first current command value of the d-axis in the system. k is the first current command value for the q-axis in the system. p1 k i1and k p3 k i3 These are the proportional and integral coefficients of the outer loop PI control for the d and q axes, respectively; x1 and x3 are the internal integral quantities of the outer loop PI controller for the d and q axes, respectively; U dc and U represents the actual and commanded values ​​of the system's DC capacitor voltage. t and This refers to the actual and commanded values ​​of the effective AC voltage at the VSC grid connection point.

[0062] Formula (1) allows for a precise and quick understanding of the specific first current command value for the d-axis and the first current command value for the q-axis.

[0063] 203. If the first current command value of the d-axis and the first current command value of the q-axis are not equal to the preset value, then the instability mode is determined to be current loop instability.

[0064] Specifically, in this embodiment, the preset value can be zero. Zero is used as the criterion for determining whether instability has occurred. That is, it is determined whether the input quantity of the current loop PI element is zero, and both the first current command value on the d-axis and the first current command value on the q-axis are not equal to the preset value. and If none of the input values ​​are zero, it indicates that the current loop is unstable. The specific method for determining whether the input value is zero is shown in formula (2):

[0065]

[0066] Among them, i d i q These are the actual values ​​of the system's d-axis and q-axis currents.

[0067] 204. If the first current command value of the d-axis and the first current command value of the q-axis are both equal to the preset value, then determine whether the input of the phase-locked loop control loop inside the voltage source converter is equal to the preset value.

[0068] Specifically, when both the first current command value of the d-axis and the first current command value of the q-axis are equal to the preset value, that is... and If the value is zero, it means that the current loop is not unstable at this time. Then it is necessary to determine whether there is phase-locked loop instability.

[0069] 205. If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability.

[0070] Specifically, the determination of whether the phase-locked loop is unstable is shown in formula (3).

[0071]

[0072] The input to the phase-locked loop control circuit includes the q-axis component of the AC voltage at the grid connection point of the voltage source converter, i.e., u. q That is, when u q When the value is not zero, it indicates that the phase-locked loop is unstable.

[0073] 206. If the input of the phase-locked loop control loop is equal to the preset value, then determine whether the input of the outer loop control loop inside the voltage source converter is equal to the preset value.

[0074] And when u q When the value is zero, it indicates that the phase-locked loop is not unstable. At this point, it is necessary to determine whether there is an unstable state in the outer loop. The specific method for determination is as shown in formula (4):

[0075]

[0076] Among them, U dc and This represents the actual and commanded values ​​of the system's DC capacitor voltage. U t and The actual and commanded values ​​of the effective AC voltage at the VSC grid connection point are the actual and commanded values. and This represents the input quantity of the outer loop control loop.

[0077] 207. If the input of the outer loop control loop is not equal to the preset value, then the instability mode is determined to be outer loop instability.

[0078] Specifically, if the input of the outer loop control loop is not equal to zero, then the instability mode is determined to be outer loop instability.

[0079] Steps 202-207 accurately determine the specific methods for identifying different instability modes when the outer loop control is engaged. The following section will further describe how to determine the specific instability mode when the outer loop control is disengaged.

[0080] 208. If the status indicates that the outer loop control loop has exited, then obtain the second current command value of the d-axis and the second current command value of the q-axis in the grid-connected system where the voltage source converter is located.

[0081] Then, based on the second current command value of the d-axis and the second current command value of the q-axis, the instability mode of the voltage source converter is determined. When the outer loop control loop exits, the second current command value of the d-axis and the second current command value of the q-axis are constant, as shown in formula (5):

[0082]

[0083] in, These are the d-axis and q-axis current command values ​​of the system when the outer loop control exits.

[0084] 209. If the second current command value of the d-axis and the second current command value of the q-axis are not equal to the preset value, then the instability mode is determined to be current loop instability.

[0085] If the second current command value of the d-axis and the second current command value of the q-axis are not equal to the preset value, that is, whether the input of the current loop PI element is zero, it indicates that the instability mode is current loop instability.

[0086] 210. If the second current command value of the d-axis and the second current command value of the q-axis are both equal to the preset value, then determine whether the input quantity of the phase-locked loop control loop is equal to the preset value.

[0087] If the second current command value of the d-axis and the second current command value of the q-axis are both equal to the preset value, that is, the current loop is not unstable, then it is necessary to determine whether there is phase-locked loop instability. The determination method is to determine whether the input of the phase-locked loop control loop is equal to the preset value.

[0088] 211. If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability.

[0089] The input value of the drag lock phase loop control loop is not equal to the preset value, i.e., u q If the value is not equal to 0, it indicates that the phase-locked loop is in an unstable state; otherwise, it is not unstable.

[0090] It should be noted that steps 202-207 and steps 208-211 are independent two-way control modes, and there is no logical relationship between the two.

[0091] Figure 3 This is the third flowchart illustrating the method for determining the large disturbance instability mode of a voltage source converter provided by the present invention.

[0092] like Figure 3 As shown, from the perspective of specific judgment formulas, the instability mode of the voltage source converter is determined. First, it is determined whether the outer loop control has exited. When the outer loop control has exited, one instability mode judgment method is executed; when the outer loop control has not exited, another instability mode judgment method is executed. The main difference between when the outer loop control has not exited and when it has exited is that the current command values ​​for the d-axis and q-axis are different. When the outer loop exits, it is only necessary to determine whether current loop instability and phase-locked loop instability exist. When the outer loop has not exited, it is necessary to determine whether current loop instability, phase-locked loop instability, and outer loop instability exist. The specific judgment method is to determine the relationship between the input values ​​of the current loop PI element, the phase-locked loop PI element, and the outer loop PI element and zero. If the input value is not zero, it is determined to be unstable; if it is zero, it is not unstable. Figure 3The meaning of each letter in the formula has been explained in detail in the above embodiments, therefore, it will not be explained in detail again.

[0093] The detailed process is as follows: Step 110: Determine if the outer loop control has exited; Step 120: Outer loop control exits, d and q axis current command values ​​are constant; Step 130: Determine if the input of the current loop PI element is 0. If not, it indicates current loop instability; Step 140: If the input of the current loop PI element is 0, determine if the input of the phase-locked loop PI element is 0. If not, it indicates phase-locked loop instability; Step 150: Outer loop control does not exit, d and q axis current command values ​​are determined by the outer loop control; Step 160: Determine if the input of the current loop PI element is 0. If not, it indicates current loop instability; Step 170: If the input of the current loop PI element is 0, determine if the input of the phase-locked loop PI element is 0. If not, it indicates phase-locked loop instability; Step 180: If the input of the phase-locked loop PI element is 0, determine if the input of the outer loop PI element is 0. If not, it indicates outer loop instability.

[0094] Based on the same general inventive concept, this application also protects a device for determining the large disturbance instability mode of a voltage source converter. The device for determining the large disturbance instability mode of a voltage source converter provided by the present invention will be described below. The device for determining the large disturbance instability mode of a voltage source converter described below and the method for determining the large disturbance instability mode of a voltage source converter described above can be referred to in correspondence with each other.

[0095] Figure 4 This is a schematic diagram of the device for determining the large disturbance instability mode of a voltage source converter provided by the present invention.

[0096] like Figure 4 As shown, this embodiment provides a device for determining the large disturbance instability mode of a voltage source converter, including:

[0097] Determining module 41 is used to determine the state of the outer loop control loop inside the voltage source converter;

[0098] The determination module 42 is used to determine the instability mode of the voltage source converter by a first preset method if the state indicates that the outer loop control link is engaged; and to determine the instability mode of the voltage source converter by a second preset method if the state indicates that the outer loop control link is disengaged; wherein the instability mode includes current loop instability mode, phase-locked loop instability mode and outer loop instability mode.

[0099] This embodiment provides a device for determining the large disturbance instability mode of a voltage source converter. It determines the state of the outer loop control loop within the voltage source converter. If the state indicates that the outer loop control loop is engaged, the instability mode of the voltage source converter is determined using a first preset method. If the state indicates that the outer loop control loop is disengaged, the instability mode of the voltage source converter is determined using a second preset method. The instability modes include current loop instability mode, phase-locked loop instability mode, and outer loop instability mode. By determining the instability mode based on the presence or absence of outer loop control, the device can quickly and accurately identify different instability modes of the voltage source converter, providing data support for setting controller parameters and designing control schemes.

[0100] Furthermore, the determination module 42 in this embodiment is specifically used for:

[0101] Determine the first current command value of the d-axis and the first current command value of the q-axis in the grid-connected system where the voltage source converter is located;

[0102] The instability mode of the voltage source converter is determined based on the first current command value of the d-axis and the first current command value of the q-axis.

[0103] Furthermore, the determination module 42 in this embodiment is specifically used for:

[0104] If the first current command value of the d-axis and the first current command value of the q-axis are both not equal to the preset value, then the instability mode is determined to be current loop instability.

[0105] If the first current command value of the d-axis and the first current command value of the q-axis are both equal to the preset value, then determine whether the input of the phase-locked loop control loop inside the voltage source converter is equal to the preset value.

[0106] If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability;

[0107] If the input of the phase-locked loop control loop is equal to the preset value, then determine whether the input of the outer loop control loop inside the voltage source converter is equal to the preset value.

[0108] If the input of the outer loop control loop is not equal to the preset value, then the instability mode is determined to be outer loop instability.

[0109] Furthermore, the determination module 42 in this embodiment is specifically used for:

[0110] Obtain the second current command value of the d-axis and the second current command value of the q-axis in the grid-connected system where the voltage source converter is located;

[0111] The instability mode of the voltage source converter is determined based on the second current command value of the d-axis and the second current command value of the q-axis.

[0112] Furthermore, the determination module 42 in this embodiment is specifically used for:

[0113] If the second current command value of the d-axis and the second current command value of the q-axis are both not equal to the preset value, then the instability mode is determined to be current loop instability.

[0114] If both the second current command value of the d-axis and the second current command value of the q-axis are equal to the preset value, then determine whether the input quantity of the phase-locked loop control loop is equal to the preset value.

[0115] If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability.

[0116] Furthermore, the input quantity of the phase-locked loop control loop in this embodiment includes the q-axis component of the AC voltage at the grid connection point of the voltage source converter.

[0117] Furthermore, the input quantity of the outer loop control loop in this embodiment includes the actual value of the DC capacitor voltage of the grid-connected system.

[0118] Furthermore, this embodiment also includes: an input module, used for:

[0119] The inputs of each control link inside the voltage source converter are obtained based on simulation and waveform recording.

[0120] Figure 5 It is a structural schematic diagram of the electronic device provided by the present invention.

[0121] like Figure 5 As shown, the electronic device may include a processor 510, a communication interface 520, a memory 530, and a communication bus 540, wherein the processor 510, the communication interface 520, and the memory 530 communicate with each other through the communication bus 540. The processor 510 can call logic instructions in the memory 530 to execute a method for determining the large disturbance instability mode of the voltage source converter. The method includes: determining the state of the outer loop control loop inside the voltage source converter; if the state indicates that the outer loop control loop is engaged, then determining the instability mode of the voltage source converter through a first preset method; if the state indicates that the outer loop control loop is disengaged, then determining the instability mode of the voltage source converter through a second preset method; wherein the instability mode includes a current loop instability mode, a phase-locked loop instability mode, and an outer loop instability mode.

[0122] Furthermore, the logical instructions in the aforementioned memory 530 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.

[0123] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the method for determining the large disturbance instability mode of a voltage source converter provided by the above methods. The method includes: determining the state of the outer loop control link inside the voltage source converter; if the state indicates that the outer loop control link is engaged, then determining the instability mode of the voltage source converter through a first preset method; if the state indicates that the outer loop control link is disengaged, then determining the instability mode of the voltage source converter through a second preset method; wherein, the instability mode includes a current loop instability mode, a phase-locked loop instability mode, and an outer loop instability mode.

[0124] In another aspect, the present invention also provides a non-transient computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements a method for determining the large disturbance instability mode of a voltage source converter provided by the methods described above. This method includes: determining the state of the outer loop control loop within the voltage source converter; if the state indicates that the outer loop control loop is engaged, determining the instability mode of the voltage source converter using a first preset method; if the state indicates that the outer loop control loop is disengaged, determining the instability mode of the voltage source converter using a second preset method; wherein the instability mode includes a current loop instability mode, a phase-locked loop instability mode, and an outer loop instability mode.

[0125] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0126] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0127] 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 method for determining the large disturbance instability mode of a voltage source converter, characterized in that, include: Determine the state of the outer loop control loop inside the voltage source converter; If the state indicates that the outer loop control is engaged, the instability mode of the voltage source converter is determined by the first preset method. If the state indicates that the outer loop control loop has exited, the instability mode of the voltage source converter is determined by the second preset method. The instability modes include current loop instability mode, phase-locked loop instability mode, and outer loop instability mode; The step of determining the instability mode of the voltage source converter through a first preset method includes: Determine the first current command value of the d-axis and the first current command value of the q-axis in the grid-connected system where the voltage source converter is located; The instability mode of the voltage source converter is determined based on the first current command value of the d-axis and the first current command value of the q-axis. The step of determining the instability mode of the voltage source converter based on the first current command value of the d-axis and the first current command value of the q-axis includes: If the first current command value of the d-axis and the first current command value of the q-axis are both not equal to the preset value, then the instability mode is determined to be current loop instability. If the first current command value of the d-axis and the first current command value of the q-axis are both equal to the preset value, then determine whether the input of the phase-locked loop control loop inside the voltage source converter is equal to the preset value. If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability; If the input of the phase-locked loop control loop is equal to the preset value, then determine whether the input of the outer loop control loop inside the voltage source converter is equal to the preset value. If the input of the outer loop control loop is not equal to the preset value, then the instability mode is determined to be outer loop instability; The step of determining the instability mode of the voltage source converter through a second preset method includes: Obtain the second current command value of the d-axis and the second current command value of the q-axis in the grid-connected system where the voltage source converter is located; The instability mode of the voltage source converter is determined based on the second current command value of the d-axis and the second current command value of the q-axis. The step of determining the instability mode of the voltage source converter based on the second current command value of the d-axis and the second current command value of the q-axis includes: If the second current command value of the d-axis and the second current command value of the q-axis are both not equal to the preset value, then the instability mode is determined to be current loop instability. If both the second current command value of the d-axis and the second current command value of the q-axis are equal to the preset value, then determine whether the input quantity of the phase-locked loop control loop is equal to the preset value. If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability.

2. The method for determining the large disturbance instability mode of a voltage source converter according to claim 1, characterized in that, The input quantities of the phase-locked loop control circuit include the q-axis component of the AC voltage at the grid connection point of the voltage source converter.

3. The method for determining the large disturbance instability mode of a voltage source converter according to claim 1, characterized in that, The input quantities of the outer loop control loop include the actual value of the DC capacitor voltage of the grid-connected system.

4. The method for determining the large disturbance instability mode of a voltage source converter according to claim 1, characterized in that, Before determining the state of the outer loop control loop inside the voltage source converter, the method further includes: The inputs of each control link inside the voltage source converter are obtained based on simulation and waveform recording.

5. A device for determining the large disturbance instability mode of a voltage source converter, characterized in that, include: The determination module is used to determine the state of the outer loop control loop inside the voltage source converter; The determination module is used to determine the instability mode of the voltage source converter by a first preset method if the state indicates that the outer loop control loop is engaged; and to determine the instability mode of the voltage source converter by a second preset method if the state indicates that the outer loop control loop is disengaged; wherein the instability mode includes current loop instability mode, phase-locked loop instability mode and outer loop instability mode. The step of determining the instability mode of the voltage source converter through a first preset method includes: Determine the first current command value of the d-axis and the first current command value of the q-axis in the grid-connected system where the voltage source converter is located; The instability mode of the voltage source converter is determined based on the first current command value of the d-axis and the first current command value of the q-axis. The step of determining the instability mode of the voltage source converter based on the first current command value of the d-axis and the first current command value of the q-axis includes: If the first current command value of the d-axis and the first current command value of the q-axis are both not equal to the preset value, then the instability mode is determined to be current loop instability. If the first current command value of the d-axis and the first current command value of the q-axis are both equal to the preset value, then determine whether the input of the phase-locked loop control loop inside the voltage source converter is equal to the preset value. If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability; If the input of the phase-locked loop control loop is equal to the preset value, then determine whether the input of the outer loop control loop inside the voltage source converter is equal to the preset value. If the input of the outer loop control loop is not equal to the preset value, then the instability mode is determined to be outer loop instability; The step of determining the instability mode of the voltage source converter through a second preset method includes: Obtain the second current command value of the d-axis and the second current command value of the q-axis in the grid-connected system where the voltage source converter is located; The instability mode of the voltage source converter is determined based on the second current command value of the d-axis and the second current command value of the q-axis. The step of determining the instability mode of the voltage source converter based on the second current command value of the d-axis and the second current command value of the q-axis includes: If the second current command value of the d-axis and the second current command value of the q-axis are both not equal to the preset value, then the instability mode is determined to be current loop instability. If both the second current command value of the d-axis and the second current command value of the q-axis are equal to the preset value, then determine whether the input quantity of the phase-locked loop control loop is equal to the preset value. If the input quantity of the phase-locked loop control loop is not equal to the preset value, then the instability mode is determined to be phase-locked loop instability.

6. 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 program, it implements the steps of the method for determining the large disturbance instability mode of the voltage source converter as described in any one of claims 1 to 4.

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