Undisturbed resynchronization control method, system and equipment after out-of-step of virtual synchronous generator and medium
By monitoring the virtual power angle and output current of the virtual synchronous generator, clearing the excitation integrator and reducing the limit value, a smooth switch from the out-of-step state to the dual-loop synchronous operation mode of the virtual synchronous generator is achieved. This solves the power surge problem caused by the direct switching of the control mode after the virtual synchronous generator loses step, and improves the autonomy and stability of the system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HNAC TECH
- Filing Date
- 2026-02-11
- Publication Date
- 2026-05-19
AI Technical Summary
When a virtual synchronous generator loses synchronization after a grid disturbance, directly switching the control mode can cause power surges and current spikes, threatening grid stability and equipment safety.
By continuously monitoring the virtual power angle and output current of the virtual synchronous generator, when the limit value is reached and out-of-step oscillation characteristics are exhibited, the virtual excitation integrator is cleared and the current limit value is reduced. When the virtual power angle is less than the preset synchronization threshold, the voltage outer loop control is restored with the current excitation voltage as the initial value to achieve smooth switching.
It eliminates power surges and current spikes in traditional switching methods, and enhances the autonomy and system stability of the virtual synchronous generator during fault recovery.
Smart Images
Figure CN122068451A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of power control technology, and in particular relates to a disturbance-free resynchronization control method, system, equipment and medium for virtual synchronous generators after loss of synchronization. Background Technology
[0002] With the continuous expansion of renewable energy power generation, the penetration rate of new energy grid-connected equipment with power electronic converters as the core in the power system is increasing. In order to improve the stability and adaptability of the power grid, virtual synchronous generator technology has emerged. This technology simulates the rotor motion equation and excitation regulation characteristics of synchronous generators, enabling the converter to have inertia and damping, and to participate autonomously in the frequency and voltage regulation of the power grid, which significantly improves the grid-friendliness of distributed power sources.
[0003] When the power grid experiences a voltage drop or a large disturbance, the output current of the virtual synchronous generator often increases sharply in order to provide effective voltage and frequency support, triggering current limiting protection. Once it enters the current limiting operation mode, it will lose its ability to simulate the external characteristics of a synchronous generator, causing its internal synchronization mechanism to fail and entering a state of out-of-synchronization operation.
[0004] Currently, after the power grid disturbance disappears, the common recovery method is to directly exit the current limiting mode and restart the normal control mode. However, because the internal state of the system (such as phase) is in a mismatched random state with the power grid when operating out of step, if the switch is made directly, a huge current and power surge will be generated at the moment of switching due to the mismatch of the state. This surge may not only trigger the system protection again, but may also damage the equipment and threaten the stability of the power grid in severe cases. Summary of the Invention
[0005] The purpose of this application is to provide a method, system, device, and medium for uninterrupted resynchronization control of a virtual synchronous generator after it loses synchronization. The method, system, device, and medium provided by this application can achieve a smooth and uninterrupted switching from the out-of-synchronization state to the dual-loop synchronous operation mode. It can fundamentally eliminate the power surges and current surges caused by random phase differences and frequency mismatches in traditional direct switching methods, and can significantly improve the autonomy, safety, and overall stability of the virtual synchronous generator in the fault recovery process.
[0006] The technical solution provided in this application is as follows: A method for disturbance-free resynchronization control after a virtual synchronous generator loses synchronization, the method comprising: The virtual power angle and output current of the virtual synchronous generator are continuously acquired. When the output current reaches the limit value and the virtual power angle exhibits out-of-step oscillation characteristics, it is determined that the virtual synchronous generator has entered the limit out-of-step state. Clear the virtual excitation integrator to bring the virtual excitation voltage to zero and reduce the current limit value; Continue to acquire the virtual power angle. When the absolute value of the virtual power angle is less than or equal to the preset synchronization threshold, sample the current virtual excitation voltage, use the current virtual excitation voltage as the initial value to start the voltage outer loop control, and restore the current limiting value.
[0007] Optionally, the virtual power angle is the difference between the virtual rotor phase angle and the grid voltage phase angle, wherein the virtual rotor phase angle is obtained by integrating the active power in the active-frequency control loop of the virtual synchronous generator, and the grid voltage phase angle is obtained through the grid-side electrical phase-locked loop.
[0008] Optionally, the virtual power angle exhibits out-of-step oscillation characteristics, including: The virtual power angle varies periodically within the range of 0° to 180°.
[0009] Optionally, the reduction of the current limiting value includes: Reduce the current limit to 70% to 95% of the current maximum allowable output current.
[0010] Optionally, the preset synchronization threshold is any value between 0.1° and 5°.
[0011] Optionally, the step of starting the voltage outer loop control with the current virtual excitation voltage as the initial value is performed simultaneously with the step of restoring the current limiting value.
[0012] Optionally, before determining that the virtual synchronous generator has entered a limiting out-of-synchronization state and clearing the virtual excitation integrator, the method further includes: The voltage outer loop control is locked, enabling the virtual synchronous generator to operate in a single-loop constant current mode.
[0013] This application also provides a disturbance-free resynchronization control system for a virtual synchronous generator after it loses synchronization, the system comprising: The monitoring module is used to continuously acquire the virtual power angle and output current of the virtual synchronous generator. When the output current reaches the limit value and the virtual power angle exhibits out-of-step oscillation characteristics, it is determined that the virtual synchronous generator has entered the limit-out-of-step state. The pre-synchronization module is used to clear the virtual excitation integrator so that the virtual excitation voltage is returned to zero and the current limit value is reduced. The synchronization switching module is used to continue acquiring the virtual power angle. When the absolute value of the virtual power angle is less than or equal to the preset synchronization threshold, the current virtual excitation voltage is sampled, and the voltage outer loop control is started with the current virtual excitation voltage as the initial value, and the current limiting value is restored.
[0014] This application also provides an electronic device, including: a processor, a memory, and a communication bus; The communication bus is used to realize the connection and communication between the processor and the memory; The processor is used to execute the non-disturbance resynchronization control processing program for virtual synchronous generator loss of synchronization stored in the memory, so as to implement the steps of the non-disturbance resynchronization control method for virtual synchronous generator loss of synchronization as described in any of the above.
[0015] This application also provides a readable storage medium storing computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the disturbance-free resynchronization control method for virtual synchronous generators after loss of synchronization as described in any of the above claims.
[0016] Compared with existing technologies, this application provides a disturbance-free resynchronization control method, system, device, and medium for virtual synchronous generators after loss of synchronization. By continuously acquiring the virtual power angle and output current of the virtual synchronous generator, when the output current reaches a limit value and the virtual power angle exhibits out-of-synchronization oscillation characteristics, the virtual synchronous generator is determined to have entered a limited out-of-synchronization state. The virtual excitation integrator is then cleared to bring the virtual excitation voltage to zero, and the current limit value is reduced. The virtual power angle is then acquired again. When the absolute value of the virtual power angle is less than or equal to a preset synchronization threshold, the current virtual excitation voltage is sampled, and the voltage outer loop control is initiated using the current virtual excitation voltage as the initial value. In this application, after determining that the virtual synchronous generator has entered the limit-out-of-synchronization state, pre-synchronization preparation is carried out by clearing the excitation and reducing the limit. Then, the moment when the virtual power angle meets the synchronization condition is captured, and the voltage outer loop control and rated current limit are seamlessly restored at that moment with the matched system state as the initial value. This enables a smooth and disturbance-free switching from the out-of-synchronization state to the dual-loop synchronous operation mode. It can fundamentally eliminate the power surge and current surge caused by random phase difference and frequency mismatch in the traditional direct switching method, and can significantly improve the autonomy, safety and overall system stability of the virtual synchronous generator in the fault recovery process. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application 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 only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a flowchart of a method for non-disturbance resynchronization control after a virtual synchronous generator loses synchronization, as disclosed in an embodiment of this application. Figure 2 The virtual power angle steady-state waveform diagram of the virtual synchronous generator used to verify the method of this application under normal operating conditions; Figure 3 This is a waveform diagram used to demonstrate the periodic oscillation of the virtual power angle when a virtual synchronous generator enters a limited synchronization loss state. Figure 4 The simulation waveform diagram is used to illustrate the dynamic process of the synthesized electromotive force E0 after the virtual excitation integrator is cleared in this application. Figure 5 This is a simulation waveform diagram to demonstrate the entire process of virtual power angle convergence and recovery to stability after pre-synchronization preparation and switching using the method of this application; Figure 6 This is a schematic diagram of the structure of a disturbance-free resynchronization control system for a virtual synchronous generator after it loses synchronization, as disclosed in an embodiment of this application. Figure 7 This is a schematic diagram of the structure of an electronic device disclosed in an embodiment of this application. Detailed Implementation
[0019] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0020] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "electrically connected to" another component, it can be directly electrically connected to or indirectly electrically connected to the other component.
[0021] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.
[0023] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.
[0024] like Figure 1 As shown in the figure, this application provides a disturbance-free resynchronization control method for a virtual synchronous generator after it loses synchronization. The method includes: S11. Continuously acquire the virtual power angle and output current of the virtual synchronous generator. When the output current reaches the limit value and the virtual power angle exhibits out-of-step oscillation characteristics, determine that the virtual synchronous generator has entered the limit out-of-step state. In this embodiment, the determination that the virtual synchronous generator has entered the limited out-of-step state is based on the simultaneous fulfillment of two key conditions: first, the output current reaches the safe limit value set by hardware or software, indicating that the system is under severe disturbance; second, the virtual power angle exhibits continuous out-of-step oscillation characteristics.
[0025] This dual-criteria design effectively eliminates situations such as instantaneous overcurrent or synchronous swing, ensuring the accuracy of state identification and laying a reliable foundation for subsequent targeted and safe resynchronization control.
[0026] S12. Clear the virtual excitation integrator to bring the virtual excitation voltage to zero and reduce the current limit value; In this embodiment, the virtual excitation voltage can be cleared by forcibly resetting the integrator output representing the excitation intensity in the reactive-voltage control loop of the virtual synchronous generator to zero; the current limit value can be reduced by temporarily lowering the current maximum allowable output current value (e.g., 1.2 pu) by a preset ratio (e.g., 90%) (e.g., lowering it to 1.08 pu).
[0027] The two operations of zeroing excitation and reducing the limit together constitute the pre-synchronization preparation stage of the system, which aims to actively eliminate the reactive power deviation accumulated during the out-of-synchronization period and weaken the power exchange intensity between the virtual synchronous generator and the grid, thereby creating favorable conditions for the rapid convergence of the virtual power angle and the smooth arrival of the synchronization point.
[0028] S13. Continue to acquire the virtual power angle. When the absolute value of the virtual power angle is less than or equal to the preset synchronization threshold, sample the current virtual excitation voltage, use the current virtual excitation voltage as the initial value to start the voltage outer loop control, and restore the current limiting value.
[0029] In this embodiment, the preset synchronization threshold is a very small angle value (e.g., 0.5°). When the absolute value of the virtual power angle is less than or equal to the preset synchronization threshold, or when the absolute value of the virtual power angle is less than or equal to the preset synchronization threshold and its rate of change approaches zero, it indicates that the phase of the internal electromotive force of the virtual synchronous generator is almost completely aligned with the phase of the grid voltage, and the synchronization point is determined to have been reached. At this time, sampling and switching operations are immediately performed to ensure that the system exits the single-loop mode at the optimal moment when the phase error is minimal. The virtual excitation voltage value at this moment is used as the initial value of the voltage outer loop, realizing the continuous connection of the control state. At the same time, the current limiting value is restored, so that the system immediately has full support capability, thereby completing the shock-free mode conversion.
[0030] Compared with existing technologies, this application provides a disturbance-free resynchronization control method, system, device, and medium for virtual synchronous generators after loss of synchronization. By continuously acquiring the virtual power angle and output current of the virtual synchronous generator, when the output current reaches a limit value and the virtual power angle exhibits out-of-synchronization oscillation characteristics, the virtual synchronous generator is determined to have entered a limited out-of-synchronization state. The virtual excitation integrator is then cleared to bring the virtual excitation voltage to zero, and the current limit value is reduced. The virtual power angle is then acquired again. When the absolute value of the virtual power angle is less than or equal to a preset synchronization threshold, the current virtual excitation voltage is sampled, and the voltage outer loop control is initiated using the current virtual excitation voltage as the initial value. In this application, after determining that the virtual synchronous generator has entered the limit-out-of-synchronization state, pre-synchronization preparation is carried out by clearing the excitation and reducing the limit. Then, the moment when the virtual power angle meets the synchronization condition is captured, and the voltage outer loop control and rated current limit are seamlessly restored at that moment with the matched system state as the initial value. This enables a smooth and disturbance-free switching from the out-of-synchronization state to the dual-loop synchronous operation mode. It can fundamentally eliminate the power surge and current surge caused by random phase difference and frequency mismatch in the traditional direct switching method, and can significantly improve the autonomy, safety and overall system stability of the virtual synchronous generator in the fault recovery process.
[0031] In one implementation, in this embodiment of the application, the virtual power angle is the difference between the virtual rotor phase angle and the grid voltage phase angle. The virtual rotor phase angle is obtained by integrating the active power in the active-frequency control loop of the virtual synchronous generator, and the grid voltage phase angle is obtained through the grid-side electrical phase-locked loop.
[0032] In this embodiment, through the above definition and acquisition method, the virtual power angle accurately represents the phase difference between the simulated rotor position inside the virtual synchronous generator and the actual voltage waveform of the power grid. The virtual rotor phase angle is generated by integrating the active power, which essentially simulates the mechanical inertia of the synchronous generator rotor. The real-time tracking of the power grid voltage phase by a high-precision phase-locked loop ensures synchronization with the reference benchmark of the real power grid. This method makes the virtual power angle a core observation that can simultaneously reflect the internal state of the system and the external power grid conditions.
[0033] As one implementation method, in this embodiment of the application, the virtual power angle exhibits out-of-step oscillation characteristics, including: The virtual power angle varies periodically within the range of 0° to 180°.
[0034] In this embodiment, under the single-loop operation mode of current limiting and voltage loop blocking, the virtual synchronous generator loses its synchronous torque with the grid. At this time, the virtual rotor inside it will accelerate or decelerate freely relative to the grid synchronous speed under the action of inertia, causing the virtual power angle to continuously increase or decrease. Due to the sinusoidal periodicity of the power angle characteristic, when the power angle exceeds 90° (stability limit point), the system loses the synchronous restoring force, so that the virtual power angle exhibits periodic "slippery pole" oscillation in the main value range of 0° to 180° (or -180° to 0°). This phenomenon is the most intuitive and reliable electrical characteristic for judging that the system has entered an essential loss of synchronization state.
[0035] As one implementation method, in this embodiment of the application, reducing the current limiting value includes: Reduce the current limit to 70% to 95% of the current maximum allowable output current.
[0036] In this embodiment, it is preferable to reduce the current limit value to 90% of the currently allowed maximum output current value.
[0037] Setting the reduction ratio to 70% to 95% is based on a balance between engineering practice and control objectives. If the ratio is too low (e.g., below 70%), it will excessively weaken the virtual synchronous generator's support capability for the power grid and may affect voltage recovery during faults. If the ratio is too high (e.g., above 95%), it will weaken the guidance effect on system dynamics and the convergence acceleration effect will not be obvious. This range ensures accelerated convergence of out-of-step phases and reduces switching impact while preserving the transient support function of the system to the greatest extent.
[0038] As one implementation method, in this embodiment of the application, the preset synchronization threshold is any value between 0.1° and 5°.
[0039] In this embodiment, the preset synchronization threshold is preferably 0.5°.
[0040] Setting the synchronization threshold range requires balancing switching accuracy and system feasibility. If the threshold is set too small (e.g., below 0.1°), the accuracy requirements of the phase detection circuit and the delay of the control system are extremely high, which may be difficult to reliably capture in a real physical system, resulting in resynchronization delay. If the threshold is set too large (e.g., above 5°), it means that switching may not completely eliminate the switching impact when there is a significant phase difference, affecting the disturbance-free effect. A range of 0.1° to 5° can ensure high synchronization accuracy while taking into account the reliability of engineering implementation.
[0041] In one implementation, in this embodiment of the application, the step of starting the voltage outer loop control with the current virtual excitation voltage as the initial value is performed simultaneously with the step of restoring the current limiting value.
[0042] In this embodiment, the simultaneous execution of the two steps is crucial for achieving a smooth switching. If the current limit is restored first and then the voltage loop is started, the system may operate at full current capacity at the moment when the voltage is not yet under control, which poses a risk of short-term loss of control. If the voltage loop is started first and then the current limit is restored, the output of the voltage loop will be calculated based on a limited current capacity, which may lead to a slow or biased initial response. By executing them simultaneously, the synchronous update of the control system state (voltage loop) and the execution capability (current limit) is ensured, so that the system is in a fully controlled and fully capable coordinated state at the moment of switching.
[0043] As one implementation method, in this embodiment of the application, before determining that the virtual synchronous generator has entered a limiting out-of-synchronization state and clearing the virtual excitation integrator, the following steps are also included: The closed-loop voltage control enables the virtual synchronous generator to operate in a single-loop constant current mode.
[0044] In this embodiment, the outer loop voltage control is the first operation automatically executed by the protection logic when the system detects that the output current has reached the limit value set by the hardware or software. This is intended to prevent the outer loop voltage controller from continuously integrating in the current saturation state, causing its output (i.e., the virtual excitation voltage command) to accumulate to an abnormally high level without limit. This avoids serious overvoltage or overcurrent impact caused by huge command deviation when exiting the limit. After locking, the outer loop voltage output remains at the value at the instant before locking, and the system switches to a single-loop constant current mode where only the inner current loop works.
[0045] As one implementation method, the method described in this application embodiment is implemented in a three-phase virtual synchronous generator grid-connected inverter. In practical implementation, a grid-connected inverter platform equipped with a digital signal processor (DSP) and a field-programmable gate array (FPGA) can be used. The steps (S11-S13) of the method described in this application embodiment are implemented by a control program running in the DSP. This program includes the active-frequency control loop, reactive-voltage control loop, virtual rotor motion equation calculation, and virtual power angle monitoring and switching logic for the virtual synchronous generator. The FPGA is responsible for tasks such as high-speed PWM (pulse width modulation) signal generation, analog signal acquisition, and hardware protection.
[0046] To verify the effectiveness of this method, the following simulations and experiments were conducted: like Figure 2 As shown, the steady-state waveform of the virtual power angle of the virtual synchronous generator under normal operating conditions (the output of the DAC-B channel is the virtual power angle signal) indicates that under dual-loop control, the virtual power angle is stable within a small angle range, and the system is in a synchronous operating state.
[0047] like Figure 3 As shown, when the virtual synchronous generator enters the limited synchronization out-of-step state, the virtual power angle exhibits a characteristic waveform of periodic oscillation (the output of the DAC-B channel is the virtual power angle signal). It can be seen that when the system enters the limited synchronization out-of-step state, the virtual power angle exhibits periodic rotation between 0° and 180°, which is consistent with the theoretical analysis.
[0048] like Figure 4 As shown, the simulated waveform of the synthetic electromotive force E0 during the dynamic process after performing the virtual excitation voltage zeroing operation of this application is illustrated. The yellow curve represents the base electromotive force Ed, and the blue curve represents the virtual excitation voltage increment ΔEd. The synthetic electromotive force E0 = Ed + ΔEd. The figure shows that after the virtual excitation integrator is zeroed during the out-of-step period, E0 quickly returns to zero, creating conditions for a smooth restart of the voltage loop.
[0049] like Figure 5 As shown, the simulation waveform of the entire process of virtual power angle convergence and recovery to stability after pre-synchronization preparation and switching using the method of this application is illustrated. The yellow curve represents the change of virtual power angle over time. It can be seen that after performing pre-synchronization preparation (zeroing excitation and reducing the amplitude limit), the oscillation amplitude of the virtual power angle gradually decreases, and when the synchronization condition is met (e.g., |δ| ≤ 0.5°, where δ is the virtual power angle), the system successfully completes the disturbance-free switching, and the virtual power angle recovers to stability.
[0050] The simulation and experimental results above show that the method proposed in this application can effectively identify out-of-synchronization state and perform pre-synchronization adjustment in actual three-phase virtual synchronous generator grid-connected systems, and achieve shock-free mode switching at the optimal synchronization point, verifying the feasibility and engineering applicability of the method.
[0051] like Figure 6As shown in the illustration, this application also provides a disturbance-free resynchronization control system for a virtual synchronous generator after it loses synchronization. The system includes: The monitoring module 61 is used to continuously acquire the virtual power angle and output current of the virtual synchronous generator. When the output current reaches the limit value and the virtual power angle exhibits out-of-step oscillation characteristics, it is determined that the virtual synchronous generator has entered the limit out-of-step state. The pre-synchronization module 62 is used to clear the virtual excitation integrator so that the virtual excitation voltage is returned to zero and the current limit value is reduced. The synchronous switching module 63 is used to continue acquiring the virtual power angle. When the absolute value of the virtual power angle is less than or equal to the preset synchronous threshold, the current virtual excitation voltage is sampled, and the voltage outer loop control is started with the current virtual excitation voltage as the initial value, and the current limiting value is restored.
[0052] like Figure 7 As shown, this application embodiment also provides an electronic device, including: a processor 71, a memory 72, and a communication bus 73; Communication bus 73 is used to realize the connection and communication between processor 71 and memory 72; The processor 71 is used to execute the non-disturbance resynchronization control processing program after the virtual synchronous generator loses synchronization stored in the memory 72, so as to implement the steps of any of the above-described non-disturbance resynchronization control methods after the virtual synchronous generator loses synchronization.
[0053] This application also provides a readable storage medium storing computer-executable instructions, which, when loaded and executed by a processor, implement the steps of any of the above-described methods for the disturbance-free resynchronization control of a virtual synchronous generator after it loses synchronization.
[0054] It should be understood that the use of terms such as "system," "device," "unit," and / or "module" in this application is merely one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.
[0055] The embodiments in this specification are described in a progressive manner, with each embodiment focusing on the related aspects. For any differences between the embodiments, or for the same or similar parts between the embodiments, please refer to each other.
[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for disturbance-free resynchronization control after a virtual synchronous generator loses synchronization, characterized in that, The method includes: The virtual power angle and output current of the virtual synchronous generator are continuously acquired. When the output current reaches the limit value and the virtual power angle exhibits out-of-step oscillation characteristics, it is determined that the virtual synchronous generator has entered the limit out-of-step state. Clear the virtual excitation integrator to bring the virtual excitation voltage to zero and reduce the current limit value; Continue to acquire the virtual power angle. When the absolute value of the virtual power angle is less than or equal to the preset synchronization threshold, sample the current virtual excitation voltage, use the current virtual excitation voltage as the initial value to start the voltage outer loop control, and restore the current limiting value.
2. The method according to claim 1, characterized in that, The virtual power angle is the difference between the virtual rotor phase angle and the grid voltage phase angle. The virtual rotor phase angle is obtained by integrating the active power in the active-frequency control loop of the virtual synchronous generator, and the grid voltage phase angle is obtained through the grid-side electrical phase-locked loop.
3. The method according to claim 1, characterized in that, The virtual power angle exhibits out-of-step oscillation characteristics, including: The virtual power angle varies periodically within the range of 0° to 180°.
4. The method according to claim 1, characterized in that, The reduced current limiting value includes: Reduce the current limit to 70% to 95% of the current maximum allowable output current.
5. The method according to claim 1, characterized in that, The preset synchronization threshold is any value between 0.1° and 5°.
6. The method according to claim 1, characterized in that, The step of starting the voltage outer loop control with the current virtual excitation voltage as the initial value is performed simultaneously with the step of restoring the current limiting value.
7. The method according to any one of claims 1 to 6, characterized in that, Before determining that the virtual synchronous generator has entered a limited synchronization out-of-synchronization state and clearing the virtual excitation integrator, the method further includes: The voltage outer loop control is locked, enabling the virtual synchronous generator to operate in a single-loop constant current mode.
8. A disturbance-free resynchronization control system for a virtual synchronous generator after loss of synchronization, characterized in that, The system includes: The monitoring module is used to continuously acquire the virtual power angle and output current of the virtual synchronous generator. When the output current reaches the limit value and the virtual power angle exhibits out-of-step oscillation characteristics, it is determined that the virtual synchronous generator has entered the limit-out-of-step state. The pre-synchronization module is used to clear the virtual excitation integrator so that the virtual excitation voltage is returned to zero and the current limit value is reduced. The synchronization switching module is used to continue acquiring the virtual power angle. When the absolute value of the virtual power angle is less than or equal to the preset synchronization threshold, the current virtual excitation voltage is sampled, and the voltage outer loop control is started with the current virtual excitation voltage as the initial value, and the current limiting value is restored.
9. An electronic device, characterized in that, include: Processor, memory, and communication bus; The communication bus is used to realize the connection and communication between the processor and the memory; The processor is used to execute the non-disturbance resynchronization control processing program for virtual synchronous generator loss of synchronization stored in the memory, so as to implement the steps of the non-disturbance resynchronization control method for virtual synchronous generator loss of synchronization as described in any one of claims 1-7.
10. A readable storage medium, characterized in that, The readable storage medium stores computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the non-disturbance resynchronization control method for virtual synchronous generators after loss of synchronization as described in any one of claims 1 to 7.