Phase jump fault recovery method and system for a grid-forming inverter

Abstract

The present invention discloses a phase jump fault recovery method and system for a grid-forming inverter. The method includes: in response to a phase jump fault occurring in the power grid and triggering a current limiting request of the grid-forming inverter, setting the -q axis current component of the current loop reference value of the grid-forming inverter to the allowable maximum current value, forming a current-limited current loop reference value and limiting the output current of the grid-forming inverter; after releasing the current limit, updating the active power of the grid-forming inverter, and using the updated active power to update the current loop reference value of the grid-forming inverter, where the current loop reference value is the current loop reference value after releasing the current limit from the current-limited current loop reference value; when the current loop reference value is less than a preset current threshold value, switching the power grid to the grid-forming control state, thereby enhancing the transient stability of the system and being able to autonomously return to this equilibrium point and restore the grid-forming operation state.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid equipment, and in particular, to a phase jump fault recovery method and system for a network-forming inverter. Background Art

[0002] As an interface between a renewable energy power generation unit and the power grid, the control performance of a grid-connected inverter is crucial for the stability of the power system. The control schemes of grid-connected inverters include a grid-following control architecture and a network-forming control architecture. The former controls the grid-connected inverter into a controlled current source, obtains the angle information in the terminal voltage through a phase-locked loop, and then controls the active power and reactive power injected into the grid; while the latter controls the grid-connected inverter into a controlled voltage source, generates the power angle information through a power synchronization mechanism, and then controls the active power injected into the grid.

[0003] When a power grid voltage fault occurs, it is necessary for the network-forming inverter to control its output current. However, the current control strategy of the current network-forming inverter greatly reduces the critical clearing angle of the grid-connected inverter system, weakens the transient stability of the system. At the same time, under the condition of phase jump fault, it is difficult for the grid-connected inverter to desaturate and recover to the voltage source state autonomously, affecting the stability of power grid operation. Summary of the Invention

[0004] In view of this, the present invention provides a phase jump fault recovery method and system for a network-forming inverter, which solves the technical problems that the current current control strategy of the network-forming inverter greatly reduces the critical clearing angle of the grid-connected inverter system, weakens the transient stability of the system, and at the same time, under the condition of phase jump fault, it is difficult for the grid-connected inverter to desaturate and recover to the voltage source state autonomously, affecting the stability of power grid operation.

[0005] The first aspect of the present invention provides a phase jump fault recovery method for a network-forming inverter, including:

[0006] In response to a phase jump fault occurring in the power grid and triggering a current limiting request of the network-forming inverter, the -q axis current component of the current loop reference value of the network-forming inverter is given an allowable maximum current value to form a limited current loop reference value and limit the output current of the network-forming inverter;

[0007] After releasing the current limit, update the active power of the network-forming inverter, and use the updated active power to update the current loop reference value of the network-forming inverter, where the current loop reference value is the current loop reference value after releasing the current limit of the limited current loop reference value;

[0008] When the current loop reference value is less than a preset current threshold value, switch the power grid to the network-forming control state.

[0009] Preferably, the condition for triggering the current limiting request of the network-forming inverter is that the modulus of the current loop reference value is greater than the allowable maximum current value.

[0010] Preferably, when triggering the current limiting request of the network-forming inverter, the d-axis current component of the current loop reference value of the network-forming inverter is set to zero.

[0011] Preferably, the condition for releasing the current limit is that the voltage at the common connection point of the power grid is higher than a preset voltage threshold.

[0012] Preferably, the step of updating the active power of the network-forming inverter includes:

[0013] When the current active power of the network-forming inverter is less than the active power reference value, the difference is calculated between the active power reference value and the current active power, and the difference result is used to update the active power of the network-forming inverter.

[0014] Preferably, the step of updating the current loop reference value of the network-forming inverter using the updated active power includes:

[0015] Perform a power difference operation between the updated active power and the active power reference value, perform droop control on the power difference result to obtain an angular frequency deviation;

[0016] Perform integral control using the angular frequency deviation to obtain a power angle;

[0017] Determine the phase according to the power angle and the angular frequency, where the angular frequency is obtained by performing integral control on the angular frequency reference value;

[0018] Use the phase to perform rotational update on the current loop reference value of the network-forming inverter.

[0019] In a second aspect, the present invention also provides a phase jump fault recovery system for a network-forming inverter, including:

[0020] A current limiting module, configured to respond to a phase jump fault occurring in the power grid and trigger a current limiting request of the network-forming inverter, set the -q axis current component of the current loop reference value of the network-forming inverter to the allowable maximum current value, form a limited current loop reference value, and limit the output current of the network-forming inverter;

[0021] A current update module, configured to update the active power of the network-forming inverter after releasing the current limit, and update the current loop reference value of the network-forming inverter using the updated active power, where the current loop reference value is the current loop reference value after releasing the current limit from the limited current loop reference value;

[0022] A state switching module, configured to switch the power grid to a grid-forming control state when the current loop reference value is less than a preset current threshold value.

[0023] In a third aspect, the present invention further provides an electronic device, which includes a memory and a processor. A computer program is stored in the memory. When the computer program is executed by the processor, the processor is caused to execute the steps of the phase jump fault recovery method of the grid-forming inverter as described in the first aspect.

[0024] In a fourth aspect, the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed, the steps of the phase jump fault recovery method of the grid-forming inverter as described in the first aspect are implemented.

[0025] In a fifth aspect, the present invention further provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer is caused to execute the steps of the phase jump fault recovery method of the grid-forming inverter as described in the first aspect.

[0026] As can be seen from the above technical solutions, when the current limit of the grid-forming inverter is triggered in the present invention, the -q axis current component of the current loop reference value of the grid-forming inverter is preferentially given as the allowable maximum current value, which greatly improves the critical clearing angle of the system, enhances the transient stability of the system, and adopts a reactive power desaturation strategy to update the active power of the grid-forming inverter, thereby updating the current loop reference value of the grid-forming inverter, eliminating the hidden danger that the grid-forming inverter converges to an abnormal equilibrium point and cannot return to the grid-forming state, ensuring that the grid-forming inverter has only one equilibrium point, and can autonomously return to this equilibrium point to restore the grid-forming operation state, guaranteeing the stable operation of the power grid. Description of the Drawings

[0027] Figure 1 It is a system architecture diagram of a grid-forming inverter;

[0028] Figure 2 It is a control block diagram of a grid-forming inverter;

[0029] Figure 3 It is a control logic diagram of a d-axis priority current control strategy;

[0030] Figure 4 It is a voltage-current vector diagram in a current limiting mode based on a d-axis current priority strategy;

[0031] Figure 5is the power angle - output power curve of the network - forming inverter before and after current limiting;

[0032] Figure 6 is the flow chart of a phase jump fault recovery method for a network - forming inverter;

[0033] Figure 7 is the relationship diagram of the output voltage vector and current vector of the network - forming inverter under the strategy of preferentially giving the - q - axis current component;

[0034] Figure 8 is the power angle - output power curve of the network - forming inverter under the strategy of preferentially giving the - q - axis current component;

[0035] Figure 9 is the control logic diagram of the phase jump fault recovery of the network - forming inverter;

[0036] Figure 10 is the power angle - output power curve of the network - forming inverter;

[0037] Figure 11 is the system power angle value change diagram during the crossing process when the power angle suddenly increases by π / 6;

[0038] Figure 12 is the system output power value during the crossing process when the power angle suddenly increases by π / 6;

[0039] Figure 13 is the structural schematic diagram of a phase jump fault recovery system for a network - forming inverter;

[0040] Figure 14 is the structural schematic diagram of an electronic device. Specific embodiments

[0041] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] A phase jump fault recovery method for a network - forming inverter provided by an embodiment of the present application can be applied to the system architecture of a network - forming inverter as shown in Figure 1 As shown in Figure 1 wherein, the inductor L f and the capacitor C f constitute the output LC filter, and L g represents the line impedance. V dc and v gThey respectively represent the DC link voltage and the grid voltage. e represents the voltage at the Point of Common Coupling (PCC), and i represents the converter-side current. The inner loop adopts a double-loop vector control to make e track the voltage reference value e ref . E and θ respectively represent the amplitude and phase of the voltage reference value e ref . P ref and P e respectively represent the active power reference value and the actual output power. k pf represents the droop coefficient of the active power loop. Δω represents the angular frequency deviation, and δ is the power angle of the grid-forming inverter, which is generated by integrating Δω. Q ref and Q e respectively represent the reactive power reference value and the actual output reactive power value. k pf represents the droop coefficient of the reactive power loop, and E0 represents the rated grid voltage amplitude.

[0043] From the perspective of the point of common coupling, the overall output characteristics of the grid-forming inverter can be regarded as a controlled voltage loop in series with a resistor. As shown in the control block diagram in Figure 2 , the grid-connected inverter is equivalent to a controlled voltage source, and the power angle information is generated through the power synchronization mechanism, thereby controlling the active power injected into the grid.

[0044] When a grid voltage fault occurs, it is necessary to limit the output current of the grid-forming inverter. As shown in Figure 3 , in the d-axis Priority-Current Control, when various grid voltage faults cause the grid-forming inverter to trigger current limiting, the power angle generated by the active power loop is directly given to the current loop. The entire current capacity of the system is allocated to the d-axis. At this time, the expression of the current reference is as follows:

[0045] Equation 1

[0046] In Equation 1, , are respectively the d-axis and q-axis current components of the current loop reference value of the grid-forming inverter, and is the allowable maximum current value of the grid-forming inverter, that is, the grid-forming inverter operates within the allowable maximum current value without triggering current limiting.

[0047] Under the d-axis priority current control strategy, after the current limiting condition is completed, it enters the normal condition. As shown in the control logic in Figure 3 , the output power of the grid-forming inverter under the d-axis priority current control strategy is expressed as follows:

[0048] Equation 2

[0049] In Equation 2, is the output power.

[0050] Under the grid-forming control strategy without triggering current limiting, the output power of the grid-forming inverter is:

[0051] Equation 3

[0052] In Equation 3, is the rated grid voltage amplitude, is the line impedance between the grid-forming inverter and the grid.

[0053] The voltage-current vector diagram under the current limiting method based on the d-axis current priority strategy is as shown in Figure 4 , where V g represents the output voltage vector of the grid-forming inverter, and I c represents the output current vector of the grid-forming inverter.

[0054] Adopting the d-axis priority current control strategy will greatly reduce the critical clearing angle of the grid-forming inverter. The power angle-output power curve of the grid-forming inverter before and after current limiting is as shown in Figure 5 . Figure 5 In , before the fault, the system operates at point a. When a grid voltage phase jump fault occurs, the grid-forming inverter will jump to the red curve due to entering current limiting, and the critical clearing angle corresponding to the red curve is point b. Before saturation, the critical clearing angle of the system corresponds to point c. Point b is between , and point c is between . Therefore, when adopting the d-axis priority current control strategy, the power angle δ of the system will finally stabilize between

[0055] , resulting in a significant reduction in the critical clearing angle of the grid-forming inverter system and weakening the transient stability of the system. Figure 5 When a grid voltage phase jump fault occurs, the grid-forming inverter cannot desaturate autonomously. As shown in

[0056] , when current limiting occurs, the equilibrium point of the system will move from point b to point d. If this is a phase jump fault during the fault, after the fault occurs, the system will always operate at point d and always be in the current limiting state, unable to desaturate autonomously and return to the rated operating point a of the voltage source state. Figure 6 For this reason, as shown in

[0057] Step S1: In response to a phase jump fault occurring in the power grid and triggering a current limit request for the grid-forming inverter, the -q axis current component of the current loop reference value of the grid-forming inverter is set to the maximum allowable current value, forming a limited current loop reference value and limiting the output current of the grid-forming inverter.

[0058] Among them, the condition for triggering the current limit request of the grid-forming inverter is that the modulus of the current loop reference value is greater than the maximum allowable current value. When the condition for triggering the current limit request of the grid-forming inverter is not met, the grid-forming inverter will automatically return to the original equilibrium point.

[0059] Among them, the -q axis current component of the current loop reference value of the grid-forming inverter is preferentially set to the maximum allowable current value compared to the d axis current component. At the same time, the d axis current component of the current loop reference value of the grid-forming inverter is set to zero. That is, the d axis and q axis current components of the current loop reference value of the grid-forming inverter are set as follows:

[0060] Equation 4

[0061] Under the strategy of preferentially setting the -q axis current component in the embodiment of the present invention, the relationship between the output voltage vector and the current vector of the grid-forming inverter is as Figure 7 shown, and the output current I of the grid-forming inverter c is along the direction of the -q axis. Then the output power of the grid-forming inverter is:

[0062] Equation 5

[0063] The power angle-output power curve of the grid-forming inverter under the strategy of preferentially setting the -q axis current component is as Figure 8 shown by the purple curve in. Figure 8 Among them, point d1 is the steady-state operating point under the current limit state, and point b1 is the operating point corresponding to the critical clearing angle under the current limit state. Point b1 is located between , so compared with the d axis current priority limit strategy, the -q axis current priority limit strategy can greatly increase the critical clearing angle of the system (increase by 90°) and improve the transient stability of the system under phase jump faults.

[0064] As Figure 9 shown in the control logic for the grid-forming inverter to recover from a phase jump fault, in this embodiment, the -q axis current component of the current loop reference value of the grid-forming inverter is set to the maximum allowable current value, forming a limited current loop reference value and sending it to the current closed-loop of the grid-forming inverter for control. Through the PWM modulator, the output current of the grid-forming inverter is modulated using the limited current loop reference value, so that the output current of the grid-forming inverter follows the limited current loop reference value and is limited within the maximum allowable current value.

[0065] Step S2, after releasing the current limiting, updating the active power of the grid-type inverter, and using the updated active power to update the current loop reference value of the grid-type inverter, the current loop reference value is the current loop reference value after releasing the current limiting.

[0066] It should be noted that the condition for releasing the current limiting is that the voltage at the public access point of the power grid is higher than the preset voltage threshold, that is, when it is detected that the voltage at the public access point of the power grid is higher than the preset voltage threshold, the current limiting is released, so that the grid-connected inverter enters normal operating conditions, where the voltage threshold can be set to 1.0pu.

[0067] After releasing the current limit, the power grid needs to be switched to the grid control state and slowly return to the original balance point, such as Figure 5 As shown in the figure, when current limiting occurs, the system's equilibrium point will move from point b to point d. If the fault is a phase jump fault, the system will always work at point d after the fault occurs, and will always be in the current limiting state. It cannot automatically exit saturation and return to the rated working point a of the voltage source state, that is, there are two equilibrium points ( Figure 5 Therefore, when a phase jump fault occurs and triggers circuit limiting, the system may still converge to the abnormal equilibrium point d1 and cannot autonomously exit saturation and return to the networking state.

[0068] Based on this, an embodiment of the present invention adopts a virtual power feedback strategy. Specifically, in the process of updating the active power of the grid-type inverter, when the current active power of the grid-type inverter is less than the active power reference value, the active power reference value and the current active power are subtracted, and the active power of the grid-type inverter is updated using the subtraction result.

[0069] Among them, the updated calculation method of the active power of the grid-connected inverter is:

[0070] Formula 6

[0071] In formula 6, is the updated active power of the grid-connected inverter, is the active power under the -q axis current component, It is the active current reference value.

[0072] like Figure 9 As shown, the process of updating the current loop reference value of the grid-type inverter using the updated active power includes:

[0073] S201, performing power difference processing on the updated active power and the active power reference value, performing droop control on the power difference result, and obtaining an angular frequency deviation;

[0074] S202. Integrate and control using the angular frequency deviation to obtain the power angle;

[0075] S203. Determine the phase based on the power angle and the angular frequency, where the angular frequency is obtained by integrating and controlling the angular frequency reference value;

[0076] S204. Rotate and update the current loop reference value of the grid-forming inverter using the phase.

[0077] Under this strategy, the power angle-output power curve of the grid-forming inverter is as Figure 10 shown. As Figure 10 can be seen, the inherent equilibrium point d1 in the current-limiting state becomes an unstable saddle point, and the operating point of the system will continue to decrease after converging to point d1 until the current meets the exit condition and converges to the unique equilibrium point a.

[0078] Step S3. When the current loop reference value is less than the preset current threshold value, switch the power grid to the grid-forming control state.

[0079] It should be noted that the feedback strategy of virtual power adopted in the embodiments of the present invention can continuously reduce the power angle value of the grid-connected inverter, and use the power angle to update the current loop reference value. During this process, the current reference value output by the voltage loop is continuously detected. When the current loop reference value is less than the preset current threshold value, the power grid is switched to the grid-forming control state and slowly returns to the original equilibrium point; when the current loop reference value is not less than the preset current threshold value, it is necessary to further update the active power of the grid-forming inverter using the feedback strategy of virtual power until the current loop reference value is less than the preset current threshold value, and then switch the power grid to the grid-forming control state for stable operation.

[0080] It should be noted that when triggering the current limit of the grid-forming inverter, the present invention preferentially sets the -q axis current component of the current loop reference value of the grid-forming inverter to the maximum allowable current value, which greatly improves the critical clearing angle of the system and enhances the transient stability of the system. And the virtual power desaturation strategy is adopted to update the active power of the grid-forming inverter, thereby updating the current loop reference value of the grid-forming inverter, eliminating the hidden danger that the grid-forming inverter converges to an abnormal equilibrium point and cannot return to the grid-forming state, ensuring that the grid-forming inverter has only one equilibrium point, and can autonomously return to this equilibrium point to restore the grid-forming operation state and ensure the stable operation of the power grid.

[0081] As Figure 11 and Figure 12They are the system power angle change and the system output power change when the phase jump fault recovery method of the grid-forming inverter proposed in the embodiment of the present application is adopted when the phase suddenly increases by π / 6. Among them, the fault occurs at 4.5 s, and the signal enabling the switch back to grid-forming control is sent at 12 s. As Figures 11 - 12 shown, after the phase jump occurs, the current limiting of the system is triggered, and the system converges to the Figure 10 abnormal equilibrium point d1 shown. When the signal enabling the switch back to grid-forming control (desaturation signal) is sent, the power angle of the grid-connected inverter continuously decreases, and when the current reference value is less than the threshold value, it switches back to grid-forming control. At this time, both the power angle and the output power recover to the power angle value before the fault. The system successfully rides through the fault.

[0082] Based on the same inventive concept, the embodiment of the present application also provides a grid-forming inverter phase jump fault recovery system for implementing the above-mentioned grid-forming inverter phase jump fault recovery method.

[0083] The implementation solution provided by this system to solve the problem is similar to the implementation solution described in the above method. Therefore, the specific limitations in one or more embodiments of the grid-forming inverter phase jump fault recovery system provided below can refer to the limitations on the grid-forming inverter phase jump fault recovery method in the above text, and will not be repeated here.

[0084] As Figure 13 shown, the embodiment of the present application provides a grid-forming inverter phase jump fault recovery system, including:

[0085] A current limiting module 100, configured to respond to a phase jump fault occurring in the power grid and trigger a current limiting request of the grid-forming inverter, set the -q axis current component of the current loop reference value of the grid-forming inverter to the maximum allowable current value, form a limited current loop reference value, and limit the output current of the grid-forming inverter;

[0086] A current update module 200, configured to update the active power of the grid-forming inverter after releasing the current limit, and update the current loop reference value of the grid-forming inverter by using the updated active power. The current loop reference value is the current loop reference value after the limited current loop reference value is released from the current limit;

[0087] A state switching module 300, configured to switch the power grid to the grid-forming control state when the current loop reference value is less than a preset current threshold value.

[0088] Wherein, the condition for triggering the current limiting request of the grid-forming inverter is that the modulus of the current loop reference value is greater than the maximum allowable current value.

[0089] When the current amplitude limiting request of the grid-type inverter is triggered, the d-axis current component of the current loop reference value of the grid-type inverter is set to zero.

[0090] The condition for releasing the current limitation is that the voltage at the public access point of the power grid is higher than a preset voltage threshold.

[0091] Among them, the active power of the grid-connected inverter is updated, including:

[0092] When the current active power of the grid-forming inverter is less than the active power reference value, the active power reference value and the current active power are subtracted, and the active power of the grid-forming inverter is updated using the subtraction result.

[0093] The current loop reference value of the grid-connected inverter is updated using the updated active power, including:

[0094] Perform power difference processing on the updated active power and the active power reference value, perform droop control on the power difference result, and obtain the angular frequency deviation;

[0095] The power angle is obtained by performing integral control using the angular frequency deviation;

[0096] Determine the phase according to the power angle and the angular frequency, wherein the angular frequency is obtained by integral control of the angular frequency reference value;

[0097] The phase is used to rotate and update the current loop reference value of the grid-connected inverter.

[0098] like Figure 14 As shown, an embodiment of the present application also provides an electronic device, the electronic device 10 includes a memory 20 and a processor 30, the memory 20 stores a computer program, and when the computer program is executed by the processor 30, the processor 30 executes the steps of the phase jump fault recovery method of the grid-type inverter in any of the above embodiments.

[0099] An embodiment of the present application also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed, the steps of the phase jump fault recovery method of the grid-type inverter in any of the above embodiments are implemented.

[0100] An embodiment of the present application also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer executes the steps of the phase jump fault recovery method of the grid-type inverter in any of the above embodiments.

[0101] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, electronic devices, computer storage media, and computer program products described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0102] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or devices.

[0103] In several embodiments provided by the present invention, it can be understood that each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and a module, a program segment, or a part of code includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved.

[0104] In several embodiments provided by the present invention, it should be understood that the disclosed systems, electronic devices, computer storage media, computer program products, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other may be through some interfaces, and the indirect couplings or communication connections of devices or units may be in electrical, mechanical, or other forms.

[0105] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0106] In addition, in each embodiment of the present invention, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0107] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this 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 for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes such as USB flash drives, mobile hard disks, read-only memories (English full name: Read-Only Memory, English abbreviation: ROM), random access memories (English full name: Random Access Memory, English abbreviation: RAM), magnetic disks, or optical discs.

[0108] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A phase jump fault recovery method for a network-forming inverter, characterized in that, Including: In response to a phase jump fault occurring in the power grid and triggering a current limiting request of the grid-forming inverter, the -q axis current component of the current loop reference value of the grid-forming inverter is given as the allowable maximum current value, a limited current loop reference value is formed, and the output current of the grid-forming inverter is limited; After releasing the current limit, the active power of the grid-forming inverter is updated, and the current loop reference value of the grid-forming inverter is updated by using the updated active power, where the current loop reference value is the current loop reference value after the current limit is released from the limited current loop reference value; The step of updating the active power of the grid-forming inverter includes: When the current active power of the grid-forming inverter is less than the active power reference value, the difference is calculated between the active power reference value and the current active power, and the active power of the grid-forming inverter is updated by using the difference result; The step of updating the current loop reference value of the grid-forming inverter by using the updated active power includes: Performing a power difference processing on the updated active power and the active power reference value, performing droop control on the power difference result to obtain an angular frequency deviation; Performing integral control by using the angular frequency deviation to obtain a power angle; Determining a phase according to the power angle and the angular frequency, where the angular frequency is obtained by performing integral control on an angular frequency reference value; Rotating and updating the current loop reference value of the grid-forming inverter by using the phase; When the current loop reference value is less than a preset current threshold value, the power grid is switched to a grid-forming control state.

2. The phase jump fault recovery method of the network-forming inverter according to claim 1, characterized in that The condition for triggering the current limiting request of the grid-forming inverter is that the modulus value of the current loop reference value is greater than the allowable maximum current value.

3. The method for recovering from a phase jump fault of a network-forming inverter according to claim 1, wherein, When triggering the current limiting request of the grid-forming inverter, the d axis current component of the current loop reference value of the grid-forming inverter is given as zero.

4. The phase jump fault recovery method of the network-forming inverter according to claim 1, characterized in that The condition for releasing the current limit is that the voltage at the common connection point of the power grid is higher than a preset voltage threshold value.

5. A phase jump fault recovery system for a network-forming inverter, characterized in that Including: A current limiting module, configured to, in response to a phase jump fault occurring in the power grid and triggering a current limiting request of the grid-forming inverter, give the -q axis current component of the current loop reference value of the grid-forming inverter as the allowable maximum current value, form a limited current loop reference value, and limit the output current of the grid-forming inverter; A current updating module, configured to update the active power of the grid-forming inverter after releasing the current limit, and update the current loop reference value of the grid-forming inverter by using the updated active power, where the current loop reference value is the current loop reference value after the current limit is released from the limited current loop reference value; Updating the active power of the grid-forming inverter includes: When the current active power of the grid-forming inverter is less than the active power reference value, the difference is calculated between the active power reference value and the current active power, and the active power of the grid-forming inverter is updated by using the difference result; Updating the current loop reference value of the grid-forming inverter by using the updated active power includes: Perform a power difference operation on the updated active power and the active power reference value, and perform droop control on the power difference result to obtain an angular frequency deviation; Use the angular frequency deviation to perform integral control to obtain a power angle; Determine a phase according to the power angle and the angular frequency, where the angular frequency is obtained by performing integral control on an angular frequency reference value; Use the phase to perform a rotational update on the current loop reference value of the grid-forming inverter; A state switching module is configured to switch the power grid to a grid-forming control state when the current loop reference value is less than a preset current threshold value.

6. An electronic device, characterized in that, The electronic device includes a memory and a processor. A computer program is stored in the memory. When the computer program is executed by the processor, the processor executes the steps of the method for recovering from a phase jump fault of a grid-forming inverter according to any one of claims 1 to 4.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed, the steps of the method for recovering from a phase jump fault of a grid-forming inverter according to any one of claims 1 to 4 are implemented.

8. A computer program product, characterized in that, The computer program product includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer is caused to execute the steps of the method for recovering from a phase jump fault of a grid-forming inverter according to any one of claims 1 to 4.

Images