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

Abstract

A phase jump fault recovery method and system for a grid-forming inverter. The method comprises: in response to a phase jump fault having occurred in a power grid and a current limiting request of a grid-forming inverter having been triggered, setting the -q-axis current component of a current loop reference value of the grid-forming inverter to an allowable maximum current value, so as to form current-limited loop reference value, and limiting an output current of the grid-forming inverter; after releasing the current limiting, 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, wherein the current loop reference value is a current loop reference value obtained after releasing the current limiting for the current-limited loop reference value; and when the current loop reference value is less than a preset current threshold value, switching the power grid to a grid-forming controlled state, thereby enhancing the transient stability of a system, and enabling the system to autonomously return to an equilibrium point and restore the grid-forming operating state.

Description

A method and system for recovering phase transition faults in grid-connected inverters

[0001] This application is required to be filed with the China Patent Office on October 16, 2024, application number:

[0002] Priority is given to Chinese Patent Application No. 202411446206.7, entitled “A Method and System for Recovering Phase Jump Faults in a Grid-Based Inverter”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of power grid equipment technology, and in particular to a method and system for recovering phase jump faults in grid-connected inverters. Background Technology

[0004] As the interface between renewable energy generation units and the power grid, the control performance of grid-connected inverters is crucial to the stability of the power system. There are two control schemes for grid-connected inverters: grid-connected control architecture and grid-connected control architecture. The former controls the grid-connected inverter as a controlled current source, obtaining angle information from the terminal voltage through a phase-locked loop (PLL) to control the active and reactive power injected into the grid. The latter controls the grid-connected inverter as a controlled voltage source, generating power angle information through a power synchronization mechanism to control the active power injected into the grid.

[0005] When a grid voltage fault occurs, grid-connected inverters are required to control their output current. However, the current control strategy of current grid-connected inverters greatly reduces the limit cut-off angle of the grid-connected inverter system, weakening the transient stability of the system. At the same time, under phase jump fault conditions, grid-connected inverters have difficulty autonomously desaturating and returning to the voltage source state, affecting the stability of grid operation. Summary of the Invention

[0006] In view of this, the present invention provides a phase jump fault recovery method and system for grid-connected inverters, which solves the technical problems that the current control strategy of current grid-connected inverters greatly reduces the limit cut-off angle of the grid-connected inverter system, weakens the transient stability of the system, and makes it difficult for the grid-connected inverter to autonomously desaturate and recover to the voltage source state under phase jump fault conditions, thus affecting the stability of grid operation.

[0007] The first aspect of this invention provides a method for recovering phase transition faults in a grid-connected inverter, comprising:

[0008] In response to a phase jump fault in the power grid and triggering a current limiting request for the grid-connected inverter, the -q-axis current component of the current loop reference value of the grid-connected inverter is given as the maximum allowable current value, forming a limiting current loop reference value and limiting the output current of the grid-connected inverter.

[0009] After the current limiting is lifted, the active power of the grid-connected inverter is updated, and the updated active power is used to update the current loop reference value of the grid-connected inverter. The current loop reference value is the current loop reference value after the current limiting is lifted.

[0010] If the current loop reference value is less than the preset current threshold value, the power grid will be switched to grid construction control state.

[0011] Preferably, the condition for triggering the current limiting request of the grid-connected inverter is that the magnitude of the current loop reference value is greater than the maximum allowable current value.

[0012] Preferably, when the current limiting request of the grid-connected inverter is triggered, the d-axis current component of the current loop reference value of the grid-connected inverter is given to zero.

[0013] Preferably, the condition for lifting the current limit is that the voltage at the common access point of the power grid is higher than a preset voltage threshold.

[0014] Preferably, the step of updating the active power of the grid-connected inverter includes:

[0015] 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.

[0016] Preferably, the step of updating the current loop reference value of the grid-connected inverter using the updated active power includes:

[0017] The updated active power is compared with the active power reference value by power difference processing, and the power difference result is subjected to droop control to obtain the angular frequency deviation.

[0018] The power angle is obtained by integral control using the angular frequency deviation.

[0019] The phase is determined based on the power angle and angular frequency, wherein the angular frequency is obtained by integral control of the angular frequency reference value.

[0020] The current loop reference value of the grid-type inverter is rotated and updated using the phase.

[0021] Secondly, the present invention also provides a phase transition fault recovery system for a grid-connected inverter, comprising:

[0022] The current limiting module is used to respond to a phase jump fault in the power grid and trigger a current limiting request of the grid-connected inverter. It sets the -q axis current component of the current loop reference value of the grid-connected inverter as the maximum allowable current value, forms a limiting current loop reference value, and limits the output current of the grid-connected inverter.

[0023] The current update module is used to update the active power of the grid-type inverter after the current limiting is lifted, and to update the current loop reference value of the grid-type inverter using the updated active power. The current loop reference value is the current loop reference value after the current limiting is lifted.

[0024] The state switching module is used to switch the power grid to a grid-connection control state when the current loop reference value is less than a preset current threshold value.

[0025] Thirdly, the present invention also provides an electronic device, the electronic device including a memory and a processor, the memory storing a computer program, the computer program being executed by the processor causing the processor to perform the steps of the phase jump fault recovery method for a grid-type inverter as described in the first aspect.

[0026] Fourthly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the steps of the phase transition fault recovery method for a grid-connected inverter as described in the first aspect.

[0027] Fifthly, the present invention also provides a computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, wherein when the program instructions are executed by a computer, the computer performs the steps of the phase transition fault recovery method for a grid-connected inverter as described in the first aspect.

[0028] As can be seen from the above technical solutions, when triggering the current limiting of the grid-connected inverter, this invention prioritizes setting the -q-axis current component of the current loop reference value of the grid-connected inverter to the maximum allowable current value, which greatly improves the system's limit cut-off angle and enhances the system's transient stability. Furthermore, the virtual power desaturation strategy adopted updates the active power of the grid-connected inverter, thereby updating the current loop reference value of the grid-connected inverter. This eliminates the hidden danger of the grid-connected inverter converging to an abnormal equilibrium point and being unable to return to the grid-connected state, ensuring that the grid-connected inverter has only one equilibrium point and can autonomously return to that equilibrium point to restore the grid-connected operating state, thus ensuring the stable operation of the power grid. Attached Figure Description

[0029] Figure 1 shows the system architecture diagram of the grid-connected inverter;

[0030] Figure 2 is a control block diagram of a grid-connected inverter;

[0031] Figure 3 is the control logic diagram of the d-axis priority current control strategy;

[0032] Figure 4 shows the voltage and current vector diagram under the current limiting method based on the d-axis current priority strategy;

[0033] Figure 5 shows the power angle-output power curves of the grid-type inverter before and after current limiting;

[0034] Figure 6 is a flowchart of a phase jump fault recovery method for a grid-type inverter;

[0035] Figure 7 shows the relationship between the output voltage vector and current vector of a grid-type inverter under the strategy of prioritizing the -q axis current component.

[0036] Figure 8 shows the power angle-output power curve of the grid-type inverter under the strategy of prioritizing the -q axis current component;

[0037] Figure 9 is the control logic diagram for phase jump fault recovery of a grid-type inverter;

[0038] Figure 10 shows the power angle-output power curve of a grid-type inverter;

[0039] Figure 11 shows the change in the system's power angle value during the crossing process when the power angle suddenly increases by π / 6.

[0040] Figure 12 shows the system output power during the crossing process when the power angle increases by π / 6;

[0041] Figure 13 is a schematic diagram of a phase jump fault recovery system for a grid-type inverter.

[0042] Figure 14 is a schematic diagram of the structure of an electronic device. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] This application provides a phase transition fault recovery method for a grid-connected inverter, which can be applied to the system architecture of the grid-connected inverter shown in Figure 1. As shown in Figure 1, the inductor L... f and capacitor C fThis forms the output LC filter, L g Indicates the line impedance. V dc and v g Here, represents the DC link voltage and the grid voltage, respectively; 'e' represents the voltage at the Point of Common Coupling (PCC), and 'i' represents the converter-side current. The inner loop uses dual-loop vector control to make 'e' track the voltage reference value 'i'. ref E and θ represent the voltage reference value e, respectively. ref The amplitude and phase of P. ref and P e These represent the reference value of active power and the actual output power, respectively. pf Q represents the droop coefficient of the active power loop, Δω represents the angular frequency deviation, and δ is the power angle of the grid inverter, which is generated by integrating Δω. ref and Q e k represents the reactive power reference value and the actual output reactive power value, respectively. pf E0 represents the droop factor of the reactive power loop and E0 represents the rated grid voltage amplitude.

[0045] From the perspective of the common access point, the overall output characteristics of the grid-connected inverter can be viewed as a controlled voltage loop resistor. As shown in the control block diagram in Figure 2, the grid-connected inverter is equivalent to a controlled voltage source, which generates power angle information through a power synchronization mechanism, thereby controlling the active power injected into the grid.

[0046] When a grid voltage fault occurs, it is necessary to limit the output current of the grid-connected inverter, as shown in Figure 3. d-axis priority-current control ensures that when various grid voltage faults trigger current limiting in the grid-connected inverter, the power angle generated by the active power loop is directly applied to the current loop. The entire system current capacity is allocated to the d-axis. In this case, the current reference expression is as follows:

[0047] In Equation 1, I dref I qref These are the d-axis and q-axis current components of the current loop reference value for a grid-connected inverter, respectively. max This is the maximum allowable current value for a grid-connected inverter, meaning that the grid-connected inverter operates within the maximum allowable current value without triggering current limiting.

[0048] Under the d-axis priority current control strategy, after the current limiting condition is completed, the inverter enters the normal operating condition, as shown in Figure 3. The output power of the grid-connected inverter under the d-axis priority current control strategy is expressed as follows: P e_saturated =I max V gcos(δ) Equation 2;

[0049] In Equation 2, P e_saturated This refers to the output power.

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

[0051] In Equation 3, E0 is the rated grid voltage amplitude, X g The line impedance between the grid-connected inverter and the power grid.

[0052] Figure 4 shows the voltage-current vector diagram under the current-limiting method based on the d-axis current-priority strategy, where V g I represents the output voltage vector of a grid-connected inverter. c This represents the output current vector of a grid-type inverter.

[0053] Adopting a d-axis priority current control strategy significantly reduces the critical cutoff angle of grid-connected inverters. Figure 5 shows the power angle-output power curves of the grid-connected inverter before and after current limiting. In Figure 5, the system operates at point a before the fault. When a grid voltage phase angle jump fault occurs, the grid-connected inverter will jump to the red curve due to current limiting, and the critical cutoff angle corresponding to the red curve is point b. Before saturation, the critical cutoff angle of the system corresponds to point c. Point b is... Between, and point c is located Therefore, when using the d-axis priority current control strategy, the system's power angle δ eventually stabilizes at [value missing]. This leads to a significant reduction in the limit cut-off angle of the grid-connected inverter system, which weakens the system's transient stability.

[0054] When a grid voltage phase angle jump fault occurs, the grid-connected inverter cannot autonomously desaturate. As shown in Figure 5, after current limiting occurs, the system's equilibrium point will shift from point b to point d. If the fault is a phase jump fault, the system will continue to operate at point d after the fault occurs, remaining in a current-limited state and unable to autonomously exit saturation and return to the rated operating point a of the voltage source state.

[0055] Therefore, as shown in Figure 6, an embodiment of this application provides a phase transition fault recovery method for a grid-connected inverter, including the following steps S1 to S3. Wherein:

[0056] Step S1: In response to a phase jump fault in the power grid and triggering a current limiting request for the grid-connected inverter, the -q axis current component of the current loop reference value of the grid-connected inverter is given as the maximum allowable current value, forming a limiting current loop reference value and limiting the output current of the grid-connected inverter.

[0057] The condition for triggering the current limiting request of the grid-connected inverter is that the magnitude of the current loop reference value is greater than the maximum allowable current value. If the current limiting request condition is not triggered, the grid-connected inverter will automatically return to its original equilibrium point.

[0058] Specifically, for the current loop reference value of a grid-connected inverter, the -q-axis current component is preferentially assigned the maximum allowable current value compared to the d-axis current component. Meanwhile, the d-axis current component of the current loop reference value is assigned zero. In other words, the d-axis and q-axis current components of the current loop reference value of the grid-connected inverter are assigned as follows:

[0059] Under the strategy of prioritizing the -q-axis current component in this embodiment of the invention, the relationship between the output voltage vector and current vector of the grid-type inverter is shown in Figure 7. The output current I of the grid-type inverter is... c Along the -q axis, the output power of the grid-connected inverter is:

[0060] The power angle-output power curve of the grid-connected inverter adopting the strategy of prioritizing the -q-axis current component is shown as the purple curve in Figure 8. In Figure 8, point d1 is the steady-state operating point under current limiting, while point b1 is the operating point corresponding to the limiting cutoff angle under current limiting. Point b1 is located at... Therefore, compared to the d-axis current-priority limiting strategy, the -q-axis current-priority limiting strategy can greatly increase the system's limit cut-off angle (by 90°), thereby improving the system's transient stability under phase jump faults.

[0061] As shown in Figure 9, the control logic for phase transition fault recovery of the grid-connected inverter is as follows: In this embodiment, the -q axis current component of the current loop reference value of the grid-connected inverter is given as the maximum allowable current value, forming a limiting current loop reference value which is sent to the current closed loop of the grid-connected inverter for control. The output current of the grid-connected inverter is modulated by the limiting current loop reference value through the PWM modulator, so that the output current of the grid-connected inverter is limited to the maximum allowable current value by following the limiting current loop reference value.

[0062] Step S2: After removing the current limiting, update the active power of the grid-connected inverter, and use the updated active power to update the current loop reference value of the grid-connected inverter. The current loop reference value is the current loop reference value after removing the current limiting.

[0063] It should be noted that the condition for lifting the current limit is that the voltage of the grid's common access point is higher than the preset voltage threshold. That is, when the voltage of the grid's common access point is detected to be higher than the preset voltage threshold, the current limit is lifted, allowing the grid-connected inverter to enter normal operating conditions. The voltage threshold can be set to 1.0 pu.

[0064] After the current limiting is lifted, the power grid needs to be switched to grid control mode and gradually return to the original equilibrium point, as shown in Figure 5. When the current limiting occurs, the system equilibrium point will move from point b to point d. If the fault is a phase jump fault, the system will continue to operate at point d after the fault occurs, always in the current limiting state, and will not be able to autonomously exit saturation and return to the rated operating point a of the voltage source state. That is, there are two equilibrium points (point a and point d1 in Figure 5). Therefore, when the phase jump fault triggers the circuit limiting, the system may still converge to the abnormal equilibrium point d1 and will not be able to autonomously exit saturation and return to the grid control state.

[0065] Based on this, the embodiments of the present invention adopt a virtual power feedback strategy. Specifically, in the process of updating the active power of the grid-connected inverter, when the current active power of the grid-connected 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-connected inverter is updated using the subtraction result.

[0066] The updated method for calculating the active power of grid-connected inverters is as follows:

[0067] In Equation 6, P e_saturated_qmod For the active power of the updated grid-connected inverter, P e_saturated_q P represents the active power under the -q axis current component. ref This is the reference value for active current.

[0068] As shown in Figure 9, the process of updating the current loop reference value of the grid-connected inverter using the updated active power includes:

[0069] S201. The updated active power is compared with the active power reference value by power difference processing, and the power difference result is subjected to droop control to obtain the angular frequency deviation.

[0070] S202. Integral control is performed using angular frequency deviation to obtain the power angle;

[0071] S203. Determine the phase based on the power angle and angular frequency, where the angular frequency is obtained by integral control of the angular frequency reference value;

[0072] S204. Rotate and update the current loop reference value of the grid-connected inverter using phase pairing.

[0073] Under this strategy, the power angle-output power curve of the grid-connected inverter is shown in Figure 10. As can be seen from Figure 10, the inherent equilibrium point d1 under the current limiting state becomes an unstable saddle point. After the system's operating point converges to point d1, it will continue to decrease until the current meets the exit condition and converges to the unique equilibrium point a.

[0074] Step S3: When the current loop reference value is less than the preset current threshold value, switch the power grid to the grid construction control state.

[0075] It should be noted that the virtual power feedback strategy adopted in this embodiment of the invention can continuously reduce the power angle value of the grid-connected inverter and update the current loop reference value using the power angle. 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, the grid is switched to grid-connected control state and gradually returns to the original equilibrium point. When the current loop reference value is not less than the preset current threshold, the active power of the grid-connected inverter needs to be further updated using the virtual power feedback strategy until the current loop reference value is less than the preset current threshold, at which point the grid is switched to grid-connected control state for stable operation.

[0076] It should be noted that when triggering the current limiting of the grid-connected inverter, this invention prioritizes setting the -q-axis current component of the current loop reference value of the grid-connected inverter to the maximum allowable current value, which greatly improves the system's limit cut-off angle and enhances the system's transient stability. Furthermore, the virtual power desaturation strategy adopted by this invention updates the active power of the grid-connected inverter, thereby updating the current loop reference value of the grid-connected inverter. This eliminates the hidden danger of the grid-connected inverter converging to an abnormal equilibrium point and being unable to return to the grid-connected state, ensuring that the grid-connected inverter has only one equilibrium point and can autonomously return to that equilibrium point to restore the grid-connected operating state, thus ensuring the stable operation of the power grid.

[0077] Figures 11 and 12 show the system power angle and system output power changes when the phase jump fault recovery method for the grid-connected inverter proposed in this application is applied during a phase jump of π / 6. The fault occurs at 4.5 seconds, and the signal enabling the switchback to grid control is triggered at 12 seconds. As shown in Figures 11 and 12, after the phase jump, the system current limiting is triggered, and the system converges to the abnormal equilibrium point d1 shown in Figure 10. When the signal enabling the switchback to grid control (de-saturation signal) is triggered, the grid-connected inverter power angle continuously decreases, and when the current reference value is less than the threshold value, it switches back to grid control. At this time, both the power angle and output power recover to the power angle value before the fault. The system fault ride-through is successful.

[0078] Based on the same inventive concept, this application also provides a phase transition fault recovery system for a grid-connected inverter for implementing the phase transition fault recovery method of the grid-connected inverter mentioned above.

[0079] The solution provided by this system is similar to the solution described in the above method. Therefore, the specific limitations of the phase jump fault recovery system embodiment for one or more grid-connected inverters provided below can be found in the limitations of the phase jump fault recovery method for grid-connected inverters above, and will not be repeated here.

[0080] As shown in Figure 13, this application embodiment provides a phase transition fault recovery system for a grid-connected inverter, including:

[0081] The current limiting module 100 is used to respond to a phase jump fault in the power grid and trigger a current limiting request of the grid-connected inverter. It sets the -q axis current component of the current loop reference value of the grid-connected inverter to the maximum allowable current value, forms a limiting current loop reference value, and limits the output current of the grid-connected inverter.

[0082] The current update module 200 is used to update the active power of the grid-connected inverter after the current limiting is lifted, and to update the current loop reference value of the grid-connected inverter using the updated active power. The current loop reference value is the current loop reference value after the current limiting is lifted.

[0083] The state switching module 300 is used to switch the power grid to the grid construction control state when the current loop reference value is less than the preset current threshold value.

[0084] The condition for triggering the current limiting request of the grid-connected inverter is that the magnitude of the current loop reference value is greater than the maximum allowable current value.

[0085] Specifically, when triggering the current limiting request of the grid-connected inverter, the d-axis current component of the current loop reference value of the grid-connected inverter is given to zero.

[0086] The condition for lifting the current limit is that the voltage at the common access point of the power grid is higher than a preset voltage threshold.

[0087] The active power of the updated grid-connected inverters includes:

[0088] When the current active power of the grid-connected 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-connected inverter is updated using the difference result.

[0089] This includes updating the current loop reference value of the grid-connected inverter using the updated active power, including:

[0090] The updated active power is compared with the active power reference value by power difference processing, and the power difference result is subjected to droop control to obtain the angular frequency deviation.

[0091] The power angle is obtained by integral control using the angular frequency deviation;

[0092] The phase is determined based on the power angle and angular frequency, where the angular frequency is obtained by integral control of the angular frequency reference value.

[0093] The current loop reference value of the grid-connected inverter is updated by rotating the phase.

[0094] As shown in Figure 14, this application embodiment also provides an electronic device. The electronic device 10 includes a memory 20 and a processor 30. The memory 20 stores a computer program. When the computer program is executed by the processor 30, the processor 30 performs the steps of the phase transition fault recovery method for a grid-type inverter as described in any of the above embodiments.

[0095] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed, implements the steps of the phase transition fault recovery method for a grid-type inverter as described in any of the above embodiments.

[0096] This application also 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, wherein when the program instructions are executed by a computer, the computer performs the steps of the phase transition fault recovery method for a grid-type inverter as described in any of the above embodiments.

[0097] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, electronic devices, computer storage media, and computer program products described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0098] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0099] In the several embodiments provided by this invention, it will be understood that each block in the flowchart or block diagram may represent a module, segment, or portion of code, which contains 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 than those shown in the figures. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved.

[0100] In the embodiments provided by this 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 instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms.

[0101] 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 units can be selected to achieve the purpose of this embodiment according to actual needs.

[0102] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0103] If the integrated unit is implemented as 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 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 for executing all or part of the steps of the methods described in the various embodiments of the present invention through a computer device (which may be a personal computer, server, or network device, etc.). The aforementioned storage medium includes: USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media capable of storing program code.

[0104] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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. Such 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 phase jump fault recovery method of a meshed network type inverter, characterized by, include: In response to a phase jump fault in the power grid and triggering a current limiting request for the grid-connected inverter, the -q-axis current component of the current loop reference value of the grid-connected inverter is given as the maximum allowable current value, forming a limiting current loop reference value and limiting the output current of the grid-connected inverter. After the current limiting is lifted, the active power of the grid-connected inverter is updated, and the updated active power is used to update the current loop reference value of the grid-connected inverter. The current loop reference value is the current loop reference value after the current limiting is lifted. If the current loop reference value is less than the preset current threshold value, the power grid will be switched to grid construction control state. 2.The phase jump fault recovery method of a grid-forming inverter according to claim 1, wherein, The condition for triggering a current limiting request for a grid-connected inverter is that the magnitude of the current loop reference value is greater than the maximum allowable current value. 3.The phase jump fault recovery method of a grid-forming inverter according to claim 1, characterized in that, When a current limiting request is triggered for a grid-connected inverter, the d-axis current component of the current loop reference value of the grid-connected inverter is set to zero. 4.The phase jump fault recovery method of a grid-forming inverter according to claim 1, wherein, The condition for lifting the current limit is that the voltage at the common access point of the power grid is higher than a preset voltage threshold. 5.The phase jump fault recovery method of a grid-forming inverter according to claim 1, wherein, The steps for updating the active power of the grid-connected inverter include: 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. 6.The phase jump fault recovery method of a grid-forming inverter according to claim 1, wherein, The step of updating the current loop reference value of the grid-connected inverter using the updated active power includes: The updated active power is compared with the active power reference value by power difference processing, and the power difference result is subjected to droop control to obtain the angular frequency deviation. The power angle is obtained by integral control using the angular frequency deviation. The phase is determined based on the power angle and angular frequency, wherein the angular frequency is obtained by integral control of the angular frequency reference value. The current loop reference value of the grid-type inverter is rotated and updated using the phase.

7. A phase jump fault recovery system for a meshed network inverter, characterized by, include: The current limiting module is used to respond to a phase jump fault in the power grid and trigger a current limiting request of the grid-connected inverter. It sets the -q axis current component of the current loop reference value of the grid-connected inverter as the maximum allowable current value, forms a limiting current loop reference value, and limits the output current of the grid-connected inverter. The current update module is used to update the active power of the grid-type inverter after the current limiting is lifted, and to update the current loop reference value of the grid-type inverter using the updated active power. The current loop reference value is the current loop reference value after the current limiting is lifted. The state switching module is used to switch the power grid to a grid-connection control state when the current loop reference value is less than a preset current threshold value.

8. An electronic device, comprising: The electronic device includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor performs the steps of the phase transition fault recovery method for a grid-connected inverter as described in any one of claims 1 to 6.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program, when executed, implements the steps of the phase jump fault recovery method of a grid-forming inverter according to any one of claims 1 to 6.

10. A computer program product, characterised in that, The computer program product comprises a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, wherein the program instructions, when executed by a computer, cause the computer to perform the steps of the phase jump fault recovery method of a grid-forming inverter according to any one of claims 1 to 6.

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