Transient cooperative control method, device and equipment of virtual synchronous generator and medium

Abstract

The invention provides a transient cooperative control method and device of a virtual synchronous generator, equipment and a medium. The method comprises the following steps: in response to a short-circuit fault of a power grid, generating a first active power reference value for improving transient power angle stability based on power grid voltage and power angle deviation after the fault; based on the power grid voltage after the fault, a set reactive current reference value and the maximum allowable current of the converter, the maximum active power capable of being output by the converter under the current operation condition is calculated to serve as a second active power reference value; and taking the minimum value of the first active power reference value and the second active power reference value as a target active power reference value, and outputting the target active power reference value to an active control ring of the virtual synchronous generator. According to the method provided by the invention, the dual goals of considering transient stability and equipment protection under the strict current limiting condition are realized, and overcurrent damage and power angle instability are effectively avoided.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of grid-connected inverters, in particular to a transient cooperative control method and device of a virtual synchronous generator, equipment and a medium. BACKGROUND

[0002] With the promotion of the "double carbon" goal, the scale of renewable energy such as wind power and photovoltaic through power electronic converters connected to the grid has increased dramatically. Most of these new energy power stations use grid-following (GFL) control strategies. The essence is to track the grid voltage phase through a phase-locked loop (PLL) and inject a specified power into the grid like a "controlled current source". Due to the lack of voltage and frequency support capability of new energy units, large-scale new energy grid-connected leads to a decrease in short-circuit ratio of the grid, and the system is prone to dynamic instability after disturbance. Grid-forming (GFM) control technology has emerged as the times require. GFM control makes the inverter simulate the external characteristics of a synchronous generator and become a "controllable voltage source" to actively provide voltage and frequency support for the grid.

[0003] At present, although the GFM technology solves the support problem in the steady state, its transient operation still faces severe challenges when the grid experiences serious faults such as three-phase short circuits.

[0004] Therefore, the application provides a transient cooperative control method, device, equipment and medium of a virtual synchronous generator to solve one of the above technical problems. SUMMARY

[0005] The purpose of the application is to provide a transient cooperative control method, device, equipment and medium of a virtual synchronous generator, which can solve at least one of the above technical problems. The specific scheme is as follows: According to the specific embodiment of the application, in a first aspect, the application provides a transient cooperative control method of a virtual synchronous generator, comprising: In response to a short-circuit fault occurring in the power grid, a first active power reference value for improving transient power angle stability is generated based on a post-fault power grid voltage and a power angle deviation; a maximum active power that the converter can output under current operating conditions is calculated as a second active power reference value based on the post-fault power grid voltage, a set reactive current reference value, and a maximum allowable current of the converter; and the minimum value between the first active power reference value and the second active power reference value is taken as a target active power reference value and output to an active control loop of the virtual synchronous generator; wherein the first active power reference value includes a steady-state power angle term, a compensation power term that is proportional to the power angle deviation, and a damping power term that is proportional to a power angle change rate, the compensation power term is used to positively intervene in the steady-state power angle term, and the damping power term is used to negatively intervene in the steady-state power angle term.

[0006] In an embodiment, the first active power reference value is calculated by the following formula: ; wherein, a post-fault converter output voltage, a post-fault power grid voltage, an equivalent connection reactance between a converter output end and a power grid connection point, a steady-state power angle, a post-fault power angle deviation relative to the steady-state power angle, a damping compensation coefficient.

[0007] In an embodiment, the second active power reference value is calculated by the following formula: ; wherein, a second active power reference value, a steady-state power grid voltage, a d-axis current in a dq-axis coordinate system; wherein, ; wherein, a q-axis current in the dq-axis coordinate system, a converter capacity current.

[0008] In an embodiment, a condition for judging that the short-circuit fault occurs in the power grid is that the power grid voltage is detected to drop below 90% of a rated voltage.

[0009] In an embodiment, the method further includes: in response to the power grid voltage recovering to above 90% of the rated voltage, replacing the target active power reference value with a steady-state active power reference value and outputting the steady-state active power reference value to the active control loop of the virtual synchronous generator.

[0010] In one embodiment, the power angle deviation is obtained by subtracting a steady-state power angle difference from an actual difference between a virtual synchronous generator output voltage phase and a grid voltage phase.

[0011] In one embodiment, the maximum allowed current of the converter is 1.2 to 1.5 times the rated current of a power electronic switching device of the converter.

[0012] According to the specific embodiments of the present application, in a second aspect, the present application provides a transient cooperative control device of a virtual synchronous generator, comprising: The fault judgment module is configured to judge whether a short-circuit fault occurs in the grid; the power angle stability control module is configured to, in response to the short-circuit fault occurring in the grid, generate a first active power reference value for improving transient power angle stability based on a post-fault grid voltage and a power angle deviation; the amplitude limiting calculation module is configured to calculate a maximum active power that can be output by the converter under a current operating condition as a second active power reference value based on the post-fault grid voltage, a set reactive current reference value, and a maximum allowed current of the converter; and the cooperative decision module is configured to output, to an active control loop of the virtual synchronous generator, a minimum value of the first active power reference value and the second active power reference value as a target active power reference value. The first active power reference value includes a steady-state power angle term, a compensation power term that is proportional to the power angle deviation, and a damping power term that is proportional to a power angle change rate. The compensation power term is configured to positively intervene in the steady-state power angle term, and the damping power term is configured to negatively intervene in the steady-state power angle term.

[0013] According to the specific embodiments of the present application, in a third aspect, the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the method of any one of the first aspect.

[0014] According to the specific embodiments of the present application, in a fourth aspect, the present application provides a computer-readable storage medium having a computer program / instruction stored thereon. The computer program / instruction is executed by a processor to implement the method of any one of the first aspect.

[0015] Compared with the prior art, the above scheme of the embodiment of the present application has at least the following beneficial effects: the present application provides a transient cooperative control method of a virtual synchronous generator, a first active power reference value is generated based on the post-fault grid voltage and the power angle deviation in response to a short-circuit fault of the grid, the value contains a steady-state reference term, a compensation term proportional to the power angle deviation, and a damping term proportional to the power angle change rate, which can actively suppress the rotor acceleration trend and enhance the system damping, thereby improving the transient power angle stability; at the same time, the maximum active power that can be output by the converter under the current operating condition is calculated as a second reference value to ensure that the output current does not exceed the safety limit of the device; finally, the smaller value of the two reference values is taken as the target value, realizing the dual goals of considering transient stability and device protection under strict current limiting conditions, and effectively avoiding overcurrent damage and power angle instability. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A flowchart of a transient cooperative control method of a virtual synchronous generator is shown; Figure 2 A typical architecture of a grid-forming converter power system is shown; Figure 3 An equal-area rule analysis diagram under a transient power angle control strategy is shown; Figure 4 A power angle change schematic diagram during a fault is shown; Figure 5 A change schematic diagram of the active power output by the converter is shown; Figure 6 A unit block diagram of a transient cooperative control device of a virtual synchronous generator according to the embodiment of the present application is shown; Figure 7 An electronic device block diagram for transient cooperative control of a virtual synchronous generator according to an exemplary embodiment is shown. DETAILED DESCRIPTION

[0017] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be described in further detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0018] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Multiple" generally includes at least two.

[0019] It should be understood that the term "and / or" as used herein merely describes associated objects, and can exist in three forms: A and / or B, A or B, and A and B. In addition, the character " / " generally represents an "or" relationship between the front and rear associated objects.

[0020] It should be understood that although the terms first, second, third, etc. can be used in embodiments of the present application to describe various elements, these descriptions are not intended to be limiting. These terms are only used to distinguish one element from another. For example, a first can be termed a second, and, similarly, a second can be termed a first, without departing from the scope of the present application.

[0021] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "upon" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined" or "if [a stated condition or event] is detected" can be interpreted to mean "upon determining" or "in response to determining" or "upon detecting [the stated condition or event]" or "in response to detecting [the stated condition or event]."

[0022] It should also be noted that the terms "comprising," "including," or any other variation thereof are intended to cover a non-exclusive inclusion, such that a product or process that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such product or process. Without more limitations, an element defined by the phrase "comprising a" does not exclude the existence of additional identical elements in the product or process that includes the stated element.

[0023] In particular, it should be noted that symbols and / or numbers present in the description, if not marked in the description of the drawings, are not drawing reference numbers.

[0024] At present, although the GFM technology solves the problem of support in the steady state, its transient operation still faces severe challenges when the power grid experiences serious faults such as three-phase short circuit: 1. Transient overcurrent problem: The overcurrent capacity of power electronic switching devices (such as IGBT) is extremely limited (usually 1.2-1.5 times the rated current). When the grid voltage drops deeply, in order to maintain the output voltage, the GFM inverter will output a huge short-circuit current, which is extremely easy to trigger protection lockout or cause device damage.

[0025] 2. Transient power angle instability problem: During the fault, the voltage at the inverter end drops sharply, resulting in a sudden decrease in the electromagnetic power output. The input power reference value is not adjusted in time, resulting in a large unbalanced power, which causes the virtual rotor to accelerate and the power angle δ to increase rapidly. If the power angle is too large after the fault is removed, the deceleration area is insufficient, which will lead to power angle instability.

[0026] 3. Conflict between reactive power support and current limiting: During the fault, the inverter needs to output a large amount of reactive current to support the recovery of the grid voltage (i.e. fault ride-through requirement), but this will squeeze the output capacity of the active current and may further increase the total current, exacerbating the overcurrent risk.

[0027] In addition, although there are some calculation methods and theoretical derivations for the configuration of virtual inertia parameters and storage capacity of energy storage for new energy AC transmission systems when encountering short-circuit faults, these methods and derivations are not mature and perfect, and the current research field lacks in-depth theoretical basis and accurate calculation means in this regard.

[0028] In view of this, the application provides a transient cooperative control method of a virtual synchronous generator, which takes into account the transient overcurrent problem and the transient power angle instability problem, and solves the conflict between reactive power support and current limiting.

[0029] The optional embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0030] The embodiments provided by the application are a transient cooperative control method of a virtual synchronous generator.

[0031] The following will be described in detail Figure 1 The embodiments of the application will be described in detail.

[0032] Figure 1 A flowchart of a transient cooperative control method of a virtual synchronous generator is shown, as shown in Figure 1 The following steps are included; S101, in response to a short-circuit fault occurring in the power grid, generating a first active power reference value for improving transient power angle stability based on the power grid voltage after the fault and the power angle deviation.

[0033] In some embodiments, the condition for determining that a short-circuit fault occurs in the power grid is that the power grid voltage is detected to drop below 90% of the rated voltage.

[0034] S102, based on the power grid voltage after the fault, the set reactive current reference value and the maximum allowable current of the converter, calculating the maximum active power that the converter can output under the current operating condition as a second active power reference value.

[0035] S103, output the minimum value between the first active power reference value and the second active power reference value to the active control loop of the virtual synchronous generator as a target active power reference value.

[0036] The first active power reference value comprises a steady-state power angle term, a compensation power term proportional to the power angle deviation, and a damping power term proportional to the power angle change rate, the compensation power term is used for positively intervening the steady-state power angle term, and the damping power term is used for negatively intervening the steady-state power angle term.

[0037] In some embodiments, based on the short-circuit fault of the power grid, the steady-state active power reference value is used to replace the target active power reference value and is output to the active control loop of the virtual synchronous generator in response to the power grid voltage recovering to more than 90% of the rated voltage.

[0038] In the embodiments of the application, the first active power reference value is generated based on the post-fault power grid voltage and the power angle deviation in response to the short-circuit fault of the power grid, the value contains a steady-state reference term, a compensation term proportional to the power angle deviation, and a damping term proportional to the power angle change rate, and can actively inhibit the rotor acceleration trend and enhance the system damping, thereby improving the transient power angle stability; meanwhile, the maximum active power that can be output by the converter under the current operating condition is calculated as the second reference value, and it is ensured that the output current does not exceed the safety limit of the equipment; finally, the smaller value between the two reference values is taken as the target value, the dual goals of considering transient stability and equipment protection under the condition of strict current limiting are realized, and overcurrent damage and power angle instability are effectively avoided.

[0039] The application provides a transient cooperative control method of a virtual synchronous generator, which is characterized in that the contradiction between power angle instability and overcurrent protection is solved simultaneously through a cooperative control mechanism. When a short-circuit fault occurs in the power grid, the system dynamically generates a first active power reference value based on the post-fault power grid voltage and the power angle deviation, simultaneously calculates the maximum safe active output capability of the converter under the current operating condition, and finally selects the smaller value between the two values as a target active power reference value and outputs the target active power reference value to the active control loop, so as to maintain the voltage support of the power grid while avoiding the overcurrent risk of the equipment and effectively improving the transient power angle stability of the system.

[0040] In some embodiments, the generation of the first active power reference value is based on a dynamic calculation of a post-fault grid voltage and a power angle deviation. The power angle deviation is obtained by subtracting a steady-state power angle deviation from an actual difference between a virtual synchronous generator output voltage phase and a grid voltage phase, which represents a degree of power angle deviation of the system after the fault. The first active power reference value includes a steady-state power angle term, a compensation power term proportional to the power angle deviation, and a damping power term proportional to a power angle change rate, wherein the compensation power term positively intervenes in the steady-state reference value to offset the power gap caused by the voltage drop, and the damping power term negatively intervenes in the steady-state reference value to suppress the rotor acceleration trend. When the grid voltage drops below 90% of the rated voltage, the system starts the control strategy, so that the compensation power term and the damping power term are dynamically adjusted according to the real-time power angle change, thereby providing effective intervention at the initial stage of the power angle deviation, and avoiding the vicious accumulation of unbalanced power.

[0041] Figure 2 A typical architecture of a grid-forming converter power system is shown.

[0042] As shown in Figure 2 , the grid-connected inverter (GFM) works in a steady state before the fault, and the left converter outputs a voltage through a filter capacitor and inductor, which is connected to the grid (GRID) through an impedance . The grid voltage is , and the power angle is in the steady state. When the fault occurs, the output voltage of the grid-forming virtual synchronous generator (VSC) and the grid voltage drop to and respectively, and the power angle is , is the power angle deviation of the power angle compared to the steady-state value during the fault.

[0043] In some embodiments, the power angle deviation is obtained by subtracting the steady-state power angle deviation from an actual difference between the virtual synchronous generator output voltage phase and the grid voltage phase.

[0044] In some embodiments, the resistance between the converter and the grid is ignored, and the line is regarded as a pure reactance element, the size of which is represented by . The active power output by the virtual synchronous generator before the fault and during the fault is and respectively, and the calculation method is shown as follows: wherein the expression of the converter output active power during the fault is expanded, and is shown as follows: ; Further, after introducing the transient power angle control strategy in the active control link, it can be considered that the power angle of the grid-connected system remains basically unchanged during the transient period, sin≈0, cos≈1, which is simplified as: ; Among them, the first term is the steady-state power angle term, and the second term is the compensation power term proportional to the power angle deviation.

[0045] Figure 3 An equal-area rule analysis diagram under the transient power angle control strategy is shown.

[0046] As shown in Figure 3 , the steady-state power angle is represented by , the critical power angle is represented by , the pink area is the acceleration area, and the green area is the deceleration area. After adding the control, the acceleration area is significantly reduced, and the power angle change is also reduced accordingly. This mode improves the transient power angle stability.

[0047] In some embodiments, the present application attempts to superimpose an electrical damping power Pd on the basis of the power reference value as a damping power term of the first active power reference value, which is calculated by the following formula: ; Among them, Kd is the damping compensation coefficient, which can be understood as the strength of the "electrical brake". The greater the value, the stronger the control system's suppression ability to the rotor speed change trend. The power angle change rate directly represents the severity of the virtual rotor instability trend, and it is introduced into the control loop as a feedback signal, which is equivalent to injecting an electrical damping power term proportional to the speed deviation into the swing equation of the virtual synchronous generator, greatly enhancing the equivalent damping ratio of the system. This component can provide significant electrical braking torque at the initial stage of rotor acceleration when the power angle has not deviated significantly.

[0048] As a possible implementation, when the grid voltage fluctuates within 90 % ~ 110 % , the active power reference value remains unchanged.

[0049] As another possible implementation, when the voltage drops below 90% , that is, when a short-circuit fault occurs, the control strategy superimposes an additional power that changes according to and an electrical braking power that changes according to on the basis of the original active power reference value of the energy storage.

[0050] On this basis, as a specific implementation, the calculation of the first active power reference value is realized by the following formula: ; wherein, is a steady-state power angle term, is a compensation power term, is a damping power term, is a post-fault converter output voltage, is a post-fault grid voltage, is an equivalent connecting reactance between the converter output terminal and the grid connection point, is a steady-state power angle, is a post-fault power angle deviation from the steady-state power angle, is a damping compensation coefficient.

[0051] In specific calculations, the post-fault converter output voltage, the post-fault grid voltage, the equivalent connecting reactance between the converter output terminal and the grid connection point, the steady-state power angle, and the post-fault power angle deviation are all input parameters, and the damping compensation coefficient is used to adjust the strength of the damping power term. This formula enables the compensation power term to be adjusted in real time according to the power angle deviation, and the damping power term provides immediate braking according to the power angle change rate, ensuring that the power angle instability trend can be effectively suppressed at the initial stage of rotor acceleration, significantly improving the equivalent damping ratio of the system.

[0052] In the embodiments of the present application, the second active power reference value is determined by the dq-axis coordinate system. Moreover, the calculation of the second active power reference value comprehensively considers the post-fault grid voltage, the set reactive current reference value, and the maximum allowable current of the converter.

[0053] In some embodiments, the value of the maximum allowable current of the converter is 1.2 to 1.5 times the rated current of the power electronic switching device of the converter.

[0054] In some embodiments, in the dq-axis coordinate system, and are the components of the voltage on the d-axis and the q-axis, respectively. and are the components of the current on the d-axis and the q-axis, respectively. wherein, for simplicity of analysis, it is assumed that the output impedance of the inverter is purely inductive, the active power P is determined only by the d-axis current , and the reactive power is determined only by the q-axis current .

[0055] For example, during normal operation, the grid-forming converter only outputs active power, and the reactive power is 0. For another example, during a fault, the converter should preferentially output reactive current to maintain voltage stability, and is limited by the converter capacity current, so the active current is calculated as follows: ; wherein, is the q-axis current in the dq-axis coordinate system, is the converter capacity current.

[0056] On this basis, the maximum active power calculation method satisfying the converter capacity is as follows: ; wherein, is the maximum active power satisfying the converter capacity, that is, the second active power reference value, is the grid steady-state voltage, is the d-axis current in the dq-axis coordinate system.

[0057] In the embodiments of the present application, in the dq-axis coordinate system, the d-axis current and the q-axis current are respectively used to calculate the active power and the reactive power, the grid steady-state voltage is used as a reference value, and the converter capacity current determines the upper limit of the current. The second active power reference value is calculated by the formula, and its essence is the maximum active power that the converter can output under the current operating condition, which ensures that the active current is not overlimited due to the reactive demand while the output reactive current maintains the voltage stability during the fault. The calculation process strictly follows the current safety constraint of the converter, so that the system maximizes the active output capability under the premise of meeting the current limit.

[0058] Based on the above embodiments, taking the smaller one of the first active power reference value and the second active power reference value can realize the grid-connected inverter transient control strategy considering both power angle stability and fault current limiting, and the value mode is as follows: ; In some specific embodiments, a single-machine grid-connected system model containing a 10kW grid-connected energy storage unit can be built in Simulink, the grid-connected energy storage moment of inertia is 0.01, the damping coefficient is 10, the line impedance Xg is 0.01H, the grid voltage is 220V, the fault occurs at 1s, the voltage drops to 0.5pu, and the fault is removed at 1.5s, and the voltage returns to the normal level.

[0059] Figure 4 A power angle change schematic diagram during a fault is shown.

[0060] As Figure 4As shown, the blue curve represents the period without control, where the power reference value remains at the rated value, and the power angle changes significantly during the fault. The red curve represents the period with control applied during the fault, where the power angle change is smaller. When the power reference value remains at the rated value during the fault, a large unbalanced power is generated due to the sharp drop in grid voltage. This unbalanced power continuously acts on the rotor motion equation, causing the rotor to accelerate continuously, the power angle to increase continuously, and the system to accumulate a large amount of kinetic energy, which can easily lead to power angle instability. After adopting the control strategy in this paper, the power angle change is significantly reduced. The fundamental reason for this is that active compensation based on real-time power angle deviation is introduced through the active power control link. The control algorithm dynamically adjusts the active power reference value according to the dynamic value acquisition method in the above embodiment. When the power angle increases due to the fault, the compensation term is generated and increases accordingly, effectively offsetting the unbalanced power, suppressing the rotor acceleration trend, reducing the acceleration area, and increasing the usable deceleration area, thereby limiting the power angle swing to a small range and maintaining the transient stability of the system.

[0061] Figure 5 A schematic diagram showing the variation of the output active power of a converter is shown.

[0062] like Figure 5 As shown, when the power reference value remains at the rated value during a fault, the converter's output active power increases uncontrollably during the fault. A grid fault causes a sharp voltage drop. To maintain rated power output, the control system attempts to increase the power angle to compensate for the power shortfall caused by the voltage drop. However, under low voltage conditions, the increase in the power angle often enters the unstable region, and its growth rate exceeds the voltage drop rate, causing the increase in the power angle to exceed the decrease in the voltage product, ultimately resulting in an abnormal increase in output active power. This is a positive feedback instability process; the larger the power angle, the more positive the unbalanced power, the faster the rotor accelerates, and the further the power angle increases. With the above control strategy, the converter's output active power can remain stable. The core lies in the introduction of an active damping mechanism based on the power angle deviation. The control algorithm dynamically adjusts the active power command based on the calculation formulas for active and reactive power. When a fault occurs and the power angle shows an increasing trend, the compensation term immediately generates an additional power command proportional to the deviation. This command essentially provides a negative feedback electrical damping torque, effectively suppressing rotor acceleration and preventing the power angle from entering the deep nonlinear instability region. Meanwhile, the new reference value is a lower and more stable power setpoint calculated based on the post-fault voltage level, which fundamentally reduces unbalanced power and allows the system to quickly converge to a new stable operating point that matches the post-fault grid conditions, thereby maintaining stable active power output. Furthermore, when the voltage drops to 0.5 pu, the short-circuit current during the fault does not exceed the converter's maximum allowable value. According to the dynamic value selection method in the above embodiment, during the fault period, the power reference value is dynamically set to the smaller of the first and second active power reference values. The application also provides a device embodiment consistent with the above-mentioned embodiment, for realizing the method steps of the above-mentioned embodiment, based on the same name meaning explanation as the above-mentioned embodiment, having the same technical effect as the above-mentioned embodiment, which will not be described here.

[0063] As shown in Figure 6 The application provides a transient cooperative control device 600 of a virtual synchronous generator, comprising: A fault judgment module 601 is configured to judge whether a short-circuit fault occurs in the power grid.

[0064] A power angle stability control module 602 is configured to, in response to the short-circuit fault occurring in the power grid, generate a first active power reference value for improving transient power angle stability based on a power grid voltage after the fault and a power angle deviation.

[0065] A limiting calculation module 603 is configured to calculate a maximum active power that can be output by the converter under the current operating condition as a second active power reference value based on the power grid voltage after the fault, a set reactive current reference value and a maximum allowable current of the converter.

[0066] A cooperative decision module 604 is configured to output the minimum value between the first active power reference value and the second active power reference value as a target active power reference value to an active control loop of the virtual synchronous generator.

[0067] The first active power reference value comprises a steady-state power angle term, a compensation power term proportional to the power angle deviation, and a damping power term proportional to the power angle change rate, the compensation power term is used for positively intervening the steady-state power angle term, and the damping power term is used for negatively intervening the steady-state power angle term.

[0068] As to the device in the above-mentioned embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment related to the method, which will not be described in detail here.

[0069] Figure 7 is a block diagram of an electronic device 700 for transient cooperative control of a virtual synchronous generator according to an exemplary embodiment.

[0070] As shown in Figure 7As shown, one embodiment of the present application provides an electronic device 700. Wherein the electronic device 700 includes a memory 701, a processor 702, an input / output (I / O) interface 703. Wherein the memory 701 is configured to store instructions. The processor 702 is configured to invoke the instructions stored in the memory 701 to execute the method of transient cooperative control of virtual synchronous generator according to the embodiments of the present application. Wherein the processor 702 is connected with the memory 701 and the I / O interface 703 respectively, for example, through a bus system and / or other forms of connection mechanism (not shown). The memory 701 can be configured to store programs and data, including the programs of the method of transient cooperative control of virtual synchronous generator according to the embodiments of the present application. The processor 702 executes various functional applications and data processing of the electronic device 700 by running the programs stored in the memory 701.

[0071] The processor 702 in the embodiments of the present application can be implemented in at least one of a hardware form of a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic array (PLA), the processor 702 can be a central processing unit (CPU) or a combination of one or several of other forms of processing units with data processing capability and / or instruction execution capability.

[0072] The memory 701 in the embodiments of the present application can include one or more computer program products, which can include various forms of computer readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may, for example, include read only memory (ROM), flash memory, hard disk drive (HDD) or solid state drive (SSD), etc.

[0073] In the embodiments of the present application, the I / O interface 703 can be used to receive input instructions (such as digital or character information, and generate key signal inputs related to user settings and function control of the electronic device 700, etc.), and can also output various information to the outside (such as images or sounds, etc.). In the embodiments of the present application, the I / O interface 703 can include one or more of a physical keyboard, function buttons (such as volume control buttons, on-off buttons, etc.), a mouse, a joystick, a trackball, a microphone, a speaker, and a touch panel, etc.

[0074] In some embodiments, the present application provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, perform any of the methods described above.

[0075] In some embodiments, the present application provides a computer program product comprising a computer program that, when executed by a processor, performs any of the methods described above.

[0076] Although the operations are described in a particular, sequential order, it should be understood that the order described is not the only manner in which the operations can be carried out, and that the embodiments can generally be practiced in the sequences other than the order described. Alternate ordering and parallelism of operations are examples of the many possible modifications to the embodiments.

[0077] The methods, apparatus, devices, and media of the present application can be implemented using standard programming techniques, with rules-based logic or other logic that is executed by a computer processor. It should be noted that the words "component" and "module," as used herein and in the claims, are intended to encompass a tangible part that is implemented using one or more lines of software code, and / or hardware implementations and / or devices that receive input.

[0078] Any of the steps, operations, or procedures described herein can be performed or implemented using one or more hardware or software modules, alone or in combination with other devices. In one embodiment, a software module is implemented using a computer program product comprising a computer-readable medium containing computer program code, which can be executed by a computer processor for performing any or all of the steps, operations, or procedures described.

[0079] The foregoing description of the present application has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the application to the precise form disclosed, and various modifications and variations are possible in light of the above teachings or can be acquired from practice of the application. Other embodiments can be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the application being indicated by the following claims.

[0080] As to the apparatus in the above-mentioned embodiments, the specific manner in which each module performs operations has been described in detail in the embodiments related to the method, and thus will not be described in detail here.

[0081] It should be further understood that, unless otherwise specified, "connected" or "coupled" means both "directly connected or coupled" and "indirectly connected or coupled" through an intervening element.

[0082] It should be further understood that, although the operations of some of the embodiments have been described in a particular, sequential order, this should not be understood as a requirement and that one or more of the operations can be performed in parallel, serially or in other orders, omitted, or combined with other operations, including from other embodiments or methods described herein and / or known to one of ordinary skill in the art.

[0083] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0084] It is to be understood that the application is not limited to the precise construction described in the specification and shown in the drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the claims that follow.

[0085] The above embodiments are only used to illustrate the technical solutions of the present application, not limit the present application; even though the present application 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 recorded in the foregoing embodiments, or make equivalent replacements for part 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 the embodiments of the present application.

Claims

1. A transient cooperative control method for a virtual synchronous generator, characterized in that, include: In response to a short-circuit fault in the power grid, a first active power reference value is generated based on the deviation between the grid voltage and the power angle after the fault to improve the transient power angle stability. Based on the grid voltage after the fault, the set reactive current reference value, and the maximum allowable current of the converter, the maximum active power that the converter can output under the current operating conditions is calculated and used as the second active power reference value. The minimum value between the first active power reference value and the second active power reference value is used as the target active power reference value and output to the active power control loop of the virtual synchronous generator. The first active power reference value includes: a steady-state power angle term, a compensation power term proportional to the power angle deviation, and a damping power term proportional to the power angle change rate. The compensation power term is used to positively intervene in the steady-state power angle term, and the damping power term is used to negatively intervene in the steady-state power angle term.

2. The method according to claim 1, characterized in that, The first active power reference value is calculated using the following formula: ； in, The converter output voltage after the fault The grid voltage after the fault This is the equivalent connection reactance between the converter output and the grid connection point. For steady-state work angle, This refers to the deviation of the power angle after a fault compared to the steady-state power angle. This is the damping compensation coefficient.

3. The method according to claim 1, characterized in that, The second active power reference value is calculated using the following formula: ； in, This is the second active power reference value. This is the steady-state voltage of the power grid. The d-axis current is in the dq-axis coordinate system; in, ; in, Let q be the current in the dq-axis coordinate system. This represents the converter's capacity current.

4. The method according to claim 1, characterized in that, The conditions for determining that a short-circuit fault has occurred in the power grid are as follows: The grid voltage was detected to have dropped to below 90% of its rated voltage.

5. The method according to claim 1, characterized in that, The method further includes: In response to the grid voltage recovering to more than 90% of the rated voltage, the target active power reference value is replaced by a steady-state active power reference value, and output to the active power control loop of the virtual synchronous generator.

6. The method according to claim 1, characterized in that, The power angle deviation is obtained in the following way: The power angle deviation is obtained by subtracting the steady-state power angle difference from the actual difference between the output voltage phase of the virtual synchronous generator and the grid voltage phase.

7. The method according to claim 1, characterized in that, The maximum allowable current of the converter is 1.2 to 1.5 times the rated current of the power electronic switching device of the converter.

8. A transient cooperative control device for a virtual synchronous generator, characterized in that, include: The fault diagnosis module is used to determine whether a short-circuit fault has occurred in the power grid; The power angle stabilization control module, in response to a short-circuit fault in the power grid, generates a first active power reference value to improve transient power angle stability based on the deviation between the grid voltage and power angle after the fault. The limiting calculation module is used to calculate the maximum active power that the converter can output under the current operating conditions based on the grid voltage after the fault, the set reactive current reference value, and the converter's maximum allowable current, and use it as the second active power reference value. The collaborative decision-making module is used to take the minimum value between the first active power reference value and the second active power reference value as the target active power reference value and output it to the active power control loop of the virtual synchronous generator. The first active power reference value includes: a steady-state power angle term, a compensation power term proportional to the power angle deviation, and a damping power term proportional to the power angle change rate. The compensation power term is used to positively intervene in the steady-state power angle term, and the damping power term is used to negatively intervene in the steady-state power angle term.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the method described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instructions are executed by the processor, they implement the method described in any one of claims 1-7.

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