Power converter for frequency support, control method and equipment

Abstract

The invention discloses a power converter for frequency support, and a control method and equipment of the power converter. The power converter comprises a power conversion circuit and a controller. The first end of the power conversion circuit is connected with a power grid, and the second end is connected with a power supply; the controller serves as a core control unit, calculates and determines an adaptive damping compensation coefficient according to the virtual inertia and the active frequency modulation coefficient of the power converter, and then achieves decoupling of a damping control link and an active frequency modulation link by adding a first-order lead-lag link in an electromagnetic power feedback channel of an active ring of the power converter. Meanwhile, in the first-order lead-lag link, the determined damping compensation coefficient is utilized to superpose transient compensation electromagnetic power for output of an electromagnetic power feedback channel, and complete network construction control logic is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power converters, in particular to a power converter for frequency support, a control method and equipment. BACKGROUND

[0002] With the rapid development of new energy power generation technology, the penetration rate of distributed power sources such as wind power and photovoltaic power in the power grid continues to increase. In order to solve the problem of power grid stability caused by the difference in characteristics between new energy power sources and traditional synchronous generators, grid-forming power converters are widely used. The power converter simulates the inertia, damping and frequency regulation characteristics of the synchronous generator to provide voltage and frequency support for the power grid, and becomes a key device in the high-penetration new energy power grid. The core control logic includes virtual inertia control, damping control and active frequency regulation control, which work together to maintain the stability of the power grid frequency.

[0003] However, the control strategy of the existing grid-forming power converter has inherent defects. The traditional damping control link and the active frequency regulation link are implemented through the same control channel, resulting in the coupling of the parameters of the two. Specifically, increasing the damping coefficient can suppress power oscillation, but will introduce an additional steady-state power deviation; reducing the damping coefficient can reduce the steady-state deviation, but will weaken the dynamic stability of the grid-connected system. This coupling relationship makes the controller parameter design fall into the dilemma of being unable to balance dynamic performance and steady-state accuracy.

[0004] At the same time, with the increase of new energy penetration, the equivalent inertia of the power grid decreases, and the traditional control strategy is difficult to meet the frequency change rate constraint and steady-state frequency deviation requirement at the same time in the high disturbance scene, which limits the further consumption of new energy. Therefore, how to decouple the damping control and active frequency regulation has become a problem to be solved in the control technology of grid-forming power converters. SUMMARY

[0005] Based on the above problems, the present application provides a power converter for frequency support, a control method and equipment.

[0006] The embodiments of the present application disclose the following technical solutions:

[0007] In a first aspect, the embodiments of the present application provide a power converter for frequency support, the power converter comprising a power conversion circuit and a controller;

[0008] The first end of the power conversion circuit is connected to the power grid, and the second end of the power conversion circuit is connected to the power source; the synchronous generator is connected to the power grid;

[0009] The controller is configured to determine a damping compensation coefficient of the power conversion circuit according to a virtual inertia of the power conversion circuit and an active frequency modulation coefficient of the power conversion circuit, and add a first-order lead-lag link to an electromagnetic power feedback channel in an active ring of the power conversion circuit to decouple a damping control link and an active frequency modulation link of the power conversion circuit, and use the damping compensation coefficient to superimpose transient-state compensation electromagnetic power on an output of the electromagnetic power feedback channel in the first-order lead-lag link.

[0010] In a possible implementation, the controller is further configured to determine the virtual inertia of the power conversion circuit according to an inertia time constant of the synchronous generator, a minimum inertia of a grid-connected system under a frequency rate of change safety constraint, and a capacity penetration rate.

[0011] In a possible implementation, the controller is further configured to determine the minimum inertia according to a maximum value of the frequency rate of change and a maximum value of a disturbance power of a regional grid-connected system.

[0012] In a possible implementation, the controller is further configured to determine the active frequency modulation coefficient of the power conversion circuit according to a minimum value of an active frequency modulation coefficient of a grid-connected system, the active frequency modulation coefficient of the synchronous generator, and the capacity penetration rate.

[0013] In a possible implementation, the controller is further configured to determine the minimum value of the active frequency modulation coefficient according to a steady-state frequency deviation range of the grid-connected system and the maximum value of the disturbance power of the regional grid-connected system.

[0014] In a possible implementation, the controller is specifically configured to determine the damping compensation coefficient according to the virtual inertia, the active frequency modulation coefficient, a damping ratio, and a time constant of the first-order lead-lag link.

[0015] In a possible implementation, the controller is further configured to perform order reduction on the active ring after the first-order lead-lag link is added by using a dominant pole method.

[0016] In a possible implementation, when the power conversion circuit is in a steady state, the transient-state compensation electromagnetic power in the first-order lead-lag link is zero.

[0017] In a possible implementation, an expression of the transient-state compensation electromagnetic power is as follows:

[0018] ;

[0019] wherein, is the transient-state compensation electromagnetic power, is electromagnetic power, a time constant of the first-order lead-lag element, a damping compensation coefficient, s is a Laplace operator, a transfer function of the first-order lead-lag element.

[0020] In a possible implementation, a transfer function of the active loop with the added first-order lead-lag element is:

[0021] ;

[0022] wherein, a reference value of the active power, an electromagnetic power, a time constant of the first-order lead-lag element, a damping compensation coefficient, s is a Laplace operator, J is a virtual inertia of the power conversion circuit, an active frequency modulation coefficient of the power conversion circuit, a rated angular frequency; K = EU / X, E is an output voltage of the power conversion circuit, U is a common coupling point voltage of the power conversion circuit, and X is an equivalent impedance between the power conversion circuit and the power grid.

[0023] In a possible implementation, a transfer function of the reduced-order active loop is:

[0024] .

[0025] In a possible implementation, the controller is configured to determine the virtual inertia of the power conversion circuit according to the following formula:

[0026] ;

[0027] wherein, a minimum value of the virtual inertia of the power conversion circuit, a minimum inertia of the grid-connected system under the frequency change rate safety constraint, an inertia time constant of the synchronous generator, a capacity penetration rate.

[0028] In a possible implementation, the controller is configured to determine the active frequency modulation coefficient of the power conversion circuit according to the following formula:

[0029] ;

[0030] wherein, an active frequency modulation coefficient of the power conversion circuit, a minimum value of the active frequency modulation coefficient of the grid-connected system, a damping compensation coefficient of the power conversion circuit, a capacity penetration ratio.

[0031] In a possible implementation, an expression of the damping compensation coefficient is:

[0032]

[0033] wherein, a damping compensation coefficient of the power conversion circuit, a damping ratio, J is a virtual inertia of the power conversion circuit, an active frequency regulation coefficient of the power conversion circuit, a rated angular frequency; K = EU / X, E is an output voltage of the power conversion circuit, U is a common coupling point voltage of the power conversion circuit, and X is an equivalent impedance between the power conversion circuit and the power grid.

[0034] In a second aspect, the embodiments of the present application disclose a control method of a power converter, the method being applied to the power converter of any of the embodiments of the first aspect, and the method comprising:

[0035] determining a damping compensation coefficient of the power conversion circuit according to a virtual inertia of the power conversion circuit and an active frequency regulation coefficient of the power conversion circuit;

[0036] adding a first-order lead-lag link to an electromagnetic power feedback channel in an active loop of the power conversion circuit, so as to decouple a damping control link and an active frequency regulation link of the power conversion circuit; and using the damping compensation coefficient to superimpose transient-state compensation electromagnetic power on an output of the electromagnetic power feedback channel in the first-order lead-lag link.

[0037] In a possible implementation, the method further comprises determining the virtual inertia of the power conversion circuit according to an inertia time constant of the synchronous generator, a minimum inertia of a grid-connected system under a frequency change rate safety constraint, and a capacity penetration ratio; and the capacity penetration ratio is a ratio of installed capacity of the power conversion circuit to total capacity of the power grid.

[0038] In a possible implementation, the method further comprises determining the minimum inertia according to a maximum value of the frequency change rate and a maximum value of disturbance power of a regional grid-connected system.

[0039] In a possible implementation, the method further comprises determining the active frequency regulation coefficient of the power conversion circuit according to a minimum value of an active frequency regulation coefficient of the grid-connected system, the active frequency regulation coefficient of the synchronous generator, and the capacity penetration ratio.

[0040] ​In one possible implementation, the method further includes determining the minimum value of the active frequency regulation coefficient based on the steady-state frequency deviation range of the grid-connected system and the maximum disturbance power of the regional grid-connected system.

[0041] In one possible implementation, determining the damping compensation coefficient of the power conversion circuit based on the virtual inertia of the power conversion circuit and the active frequency modulation coefficient of the power conversion circuit includes: determining the damping compensation coefficient based on the virtual inertia, the active frequency modulation coefficient, the damping ratio, and the time constant of the first-order lead-lag element.

[0042] In one possible implementation, the method further includes using the dominant pole method to reduce the order of the active power loop after adding a first-order lead-lag element.

[0043] In one possible implementation, when the power conversion circuit is in a steady state, the transient compensation electromagnetic power in the first-order lead-lag element is zero.

[0044] When the power conversion circuit is in steady state, the electromagnetic power of transient compensation in the first-order lead-lag element is zero.

[0045] In one possible implementation, the expression for the electromagnetic power of the transient compensation is:

[0046] ;

[0047] in, The electromagnetic power for the transient compensation, Electromagnetic power, Let be the time constant of the first-order lead-lag element. Let be the damping compensation coefficient, and s be the Laplace operator. It is the transfer function of a first-order lead-lag element.

[0048] In one possible implementation, the transfer function of the active power loop with the added first-order lead-lag element is:

[0049] ;

[0050] in, This is a reference value for active power. Electromagnetic power, Let be the time constant of the first-order lead-lag element. Here, s is the damping compensation coefficient, s is the Laplace operator, and J is the virtual inertia of the power conversion circuit. The active frequency modulation coefficient of the power conversion circuit is denoted as . The rated angular frequency is K = EU / X, where E is the output voltage of the power conversion circuit, U is the common coupling point voltage of the power conversion circuit, and X is the equivalent impedance between the power conversion circuit and the power grid.

[0051] In one possible implementation, the transfer function of the reduced-order active power loop is:

[0052] .

[0053] In one possible implementation, the controller is used to determine the virtual inertia of the power conversion circuit according to the following formula:

[0054] ;

[0055] in, This represents the minimum virtual inertia of the power conversion circuit. The minimum inertia of the grid-connected system under the safety constraint of the rate of change of frequency is given. The inertial time constant of the synchronous generator is... The capacity permeability is denoted as .

[0056] In one possible implementation, the controller is used to determine the active frequency modulation coefficient of the power conversion circuit according to the following formula:

[0057] ;

[0058] in, The active frequency modulation coefficient of the power conversion circuit is denoted as . This represents the minimum active power frequency regulation coefficient of the grid-connected system. The active power frequency regulation coefficient of the synchronous generator is denoted as . The capacity permeability is denoted as .

[0059] In one possible implementation, the expression for the damping compensation coefficient is:

[0060] ;

[0061] in, The damping compensation coefficient is... Where J is the damping ratio, and J is the virtual inertia of the power conversion circuit. The active frequency modulation coefficient of the power conversion circuit is denoted as . The rated angular frequency is K = EU / X, where E is the output voltage of the power conversion circuit, U is the common coupling point voltage of the power conversion circuit, and X is the equivalent impedance between the power conversion circuit and the power grid.

[0062] Thirdly, embodiments of this application disclose a control device, including a processor and a memory, wherein the memory is used to store programs, instructions or code, and the processor is used to execute the programs, instructions or code in the memory to perform the control method of the power converter as described in any of the second aspects.

[0063] Fourthly, embodiments of this application disclose a computer-readable storage medium, characterized in that it stores a computer program, which is loaded by a processor to execute the control method of the power converter as described in any of the second aspects.

[0064] This application provides a power converter, a control method for the power converter, and an apparatus. The power converter includes a power conversion circuit and a controller. The first terminal of the power conversion circuit is connected to the power grid, and the second terminal is connected to a power source; the power grid also connects to a synchronous generator. The controller, as the core control unit, first calculates and determines the appropriate damping compensation coefficient based on the power converter's virtual inertia and active power frequency regulation coefficient. Then, by adding a first-order lead-lag element to the electromagnetic power feedback channel of the power converter's active power loop, the damping control element and the active power frequency regulation element are decoupled. Simultaneously, in this first-order lead-lag element, the determined damping compensation coefficient is used to superimpose transient compensation electromagnetic power onto the output of the electromagnetic power feedback channel, forming a complete network control logic.

[0065] This application embodiment separates the damping control and active power frequency regulation stages in terms of control logic by adding a first-order lead-lag element to the electromagnetic power feedback channel. The damping compensation coefficient can be used independently to optimize the dynamic stability of the grid-connected system, such as suppressing power oscillations; while the active power frequency regulation coefficient can be used independently to ensure the steady-state accuracy of the system, such as maintaining the frequency deviation within the allowable range. Combined with the damping compensation coefficient determined based on virtual inertia and the active power frequency regulation coefficient, and superimposed with transient compensation electromagnetic power, the damping compensation coefficient can independently optimize the dynamic stability of the grid-connected system to suppress power oscillations, and the active power frequency regulation coefficient can independently ensure steady-state accuracy to control frequency deviation. The active power frequency regulation stage and the damping control stage no longer affect each other, allowing the controller to achieve good dynamic response and steady-state performance under various operating conditions (such as load changes and fluctuations in new energy output) according to the specific needs of grid operation, thereby improving the overall stability and control flexibility of the grid-connected system. Attached Figure Description

[0066] 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.

[0067] Figure 1 This is a schematic diagram of the structure of a grid-connected system provided in an embodiment of this application;

[0068] Figure 2 A schematic diagram of an active power loop with an added first-order lead-lag element provided in an embodiment of this application;

[0069] Figure 3 This is a schematic diagram illustrating the calculation process for determining the damping compensation coefficient, as provided in an embodiment of this application. Detailed Implementation

[0070] As described earlier, with the continuous increase in the penetration rate of new energy sources, grid-connected power converters are widely used because they can simulate the characteristics of synchronous generators to provide frequency support for the power grid. Traditional power converters simulate the characteristics of synchronous generators through virtual inertia and damping coefficients. However, while increasing the damping coefficient can suppress power oscillations (dynamic performance), it will lead to steady-state power deviation (steady-state accuracy), forming a seesaw effect between dynamic and steady-state performance. This makes it difficult to achieve both dynamic stability and steady-state accuracy, thus limiting the absorption of new energy sources.

[0071] To address this technical problem, this application provides a power converter, a control method for the power converter, and an apparatus. The power converter includes a power conversion circuit and a controller. The first terminal of the power conversion circuit is connected to the power grid, and the second terminal is connected to a power source; the power grid also connects to a synchronous generator. The controller, as the core control unit, first calculates and determines the appropriate damping compensation coefficient based on the power converter's virtual inertia and active power frequency regulation coefficient. Then, by adding a first-order lead-lag element to the electromagnetic power feedback channel of the power converter's active power loop, the damping control element and the active power frequency regulation element are decoupled. Simultaneously, in this first-order lead-lag element, the determined damping compensation coefficient is used to superimpose transient compensation electromagnetic power onto the output of the electromagnetic power feedback channel, forming a complete grid-based control logic.

[0072] This application embodiment separates the damping control and active power frequency regulation stages in terms of control logic by adding a first-order lead-lag element to the electromagnetic power feedback channel. The damping compensation coefficient can be used independently to optimize the dynamic stability of the grid-connected system, such as suppressing power oscillations; while the active power frequency regulation coefficient can be used independently to ensure the steady-state accuracy of the system, such as maintaining the frequency deviation within the allowable range. Combined with the damping compensation coefficient determined based on virtual inertia and the active power frequency regulation coefficient, and superimposed with transient compensation electromagnetic power, the damping compensation coefficient can independently optimize the dynamic stability of the grid-connected system to suppress power oscillations, and the active power frequency regulation coefficient can independently ensure steady-state accuracy to control frequency deviation. The active power frequency regulation stage and the damping control stage no longer affect each other, allowing the controller to achieve good dynamic response and steady-state performance under various operating conditions (such as load changes and fluctuations in new energy output) according to the specific needs of grid operation, thereby improving the overall stability and control flexibility of the grid-connected system.

[0073] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0074] This application embodiment uses a power converter (specifically a grid-type power converter) as the core hardware carrier, and relies on the coordinated connection between the power converter and the power grid, power source and synchronous generator to achieve the grid connection stability requirements under high new energy penetration.

[0075] The power converters in this application are applicable to grid-connected scenarios such as distribution networks and regional transmission networks where the penetration rate of new energy sources is gradually increasing. Examples include distributed photovoltaic power stations, clustered grid-connected wind farms, industrial park power grids that combine new energy and traditional power sources, and microgrids in remote areas that require active frequency support from grid-type equipment.

[0076] In these scenarios, the power converter, through the decoupled control logic of the controller, works with the synchronous generator to maintain grid frequency stability. It is particularly suitable for high-frequency disturbance scenarios such as fluctuations in new energy output and sudden load changes, solving the problem of the contradiction between dynamic and steady-state performance of traditional grid-connected equipment under high penetration, and ensuring the reliable operation of the grid.

[0077] See Figure 1 , Figure 1 This is a schematic diagram of a grid-connected system provided in an embodiment of this application. The grid-connected system includes a power converter, a synchronous generator, and a power grid.

[0078] The power converter includes a power conversion circuit and a controller. The first terminal of the power conversion circuit is connected to the power grid, while the second terminal can be connected to renewable energy sources such as wind power and solar power. A synchronous generator is connected to the power grid in parallel with the power converter.

[0079] The grid-connected system adopts a topology in which power converters and traditional synchronous generators are connected to the grid in parallel. This not only retains the basic stability support role of traditional synchronous generators for the grid, but also enables the grid-friendly connection of new energy sources through power converters, adapting to the grid operation needs of the gradually increasing penetration rate of new energy sources.

[0080] As the energy transmission and distribution carrier of the entire grid-connected system, the power grid is a common connection platform for power converters, synchronous generators, and various electrical loads. Its stable operation depends on the coordinated matching of the inertia, damping, and frequency regulation capabilities of the connected equipment. The power grid can be a power network at different levels, such as a distribution network, a regional transmission network, or a microgrid.

[0081] Synchronous generators, as the core hardware of traditional power sources, are typically paired with primary energy plants such as thermal power and hydropower. Synchronous generators convert mechanical energy into electrical energy through the principle of electromagnetic induction. After being connected to the power grid, the synchronous generator, relying on the inherent inertia and damping characteristics of its physical rotor, provides fundamental frequency support for the power grid, suppressing frequency abrupt changes and oscillations. It is a fundamental support unit for the stable operation of the grid-connected system.

[0082] Power converters are the key link connecting new energy sources to the power grid. A power converter includes a power conversion circuit and a controller.

[0083] The power conversion circuit employs a converter topology (such as a two-level or three-level inverter topology) composed of power electronic switching devices (e.g., insulated-gate bipolar transistors, silicon carbide MOSFETs, etc.). The first terminal of the power conversion circuit can be connected to the power grid via a circuit breaker or filter, while the second terminal can be directly connected to renewable energy sources such as wind power or solar power. The power conversion circuit can convert the unstable DC power (solar power) or frequency-converted AC power (wind power) output from renewable energy sources into power frequency AC power that conforms to grid standards, achieving efficient energy transfer.

[0084] As the core of the power converter, the controller can be a high-performance processor such as a Digital Signal Processing (DSP) chip or a Field Programmable Gate Array (FPGA). The controller performs logic such as calculating damping compensation coefficients and controlling first-order lead-lag elements, outputting control signals to drive the switching devices in the power conversion circuit, achieving coordinated optimization of virtual inertia, damping control, and active power frequency regulation.

[0085] This application embodiment adds a first-order lead-lag element to the electromagnetic power feedback channel in the active loop of the power conversion circuit, thereby decoupling the damping control element and the active frequency modulation element of the power conversion circuit.

[0086] In the first-order lead-lag element, the damping compensation coefficient is used to superimpose the electromagnetic power of the electromagnetic power feedback channel output and the transient compensation electromagnetic power.

[0087] The active power loop is the closed-loop control path in the power converter's control system responsible for regulating and stabilizing the output active power.

[0088] The electromagnetic power feedback channel is used to feed back the electromagnetic power from the output side of the power converter to the comparator or regulator of the controller.

[0089] This embodiment of the application superimposes a first-order lead-lag element onto the electromagnetic power feedback channel. The electromagnetic power is processed by combining this first-order lead-lag element with a damping compensation coefficient to obtain transiently compensated electromagnetic power. This transiently compensated electromagnetic power is then used as a correction signal and superimposed onto the original electromagnetic power feedback channel. The transiently compensated electromagnetic power only functions during transient processes (such as power surges or frequency fluctuations), providing an additional damping torque to the grid-connected system and quickly suppressing oscillations. During steady-state processes (after the grid-connected system stabilizes), the transiently compensated electromagnetic power gradually decays to zero, without interfering with the precise regulation of active power.

[0090] A first-order lead-lag element takes electromagnetic power as input and outputs transient compensation electromagnetic power. At different frequencies, the first-order lead-lag element is used to change the phase and amplitude of the signal. When the signal frequency is much higher than 1 / T1 (lead characteristic), the first-order lead-lag element causes the output signal to lead the input signal, mainly used to enhance the dynamic response and stability of the grid-connected system and suppress its oscillations. When the signal frequency is much lower than 1 / T2 (lag characteristic), the first-order lead-lag element causes the output signal to lag the input signal, mainly used to improve the steady-state accuracy of the system.

[0091] In the embodiments of this application, the controller utilizes the transient lead and steady-state lag characteristics of the first-order lead-lag element to decouple the damping control element and the active frequency regulation element.

[0092] In one possible implementation, the active power loop with a first-order lead-lag element can be as follows: Figure 2 As shown.

[0093] exist Figure 2 In the active power loop shown, the rated angular frequency is... and real-time angular frequency As the input to the angular frequency difference detection stage of the active power loop, the rated angular frequency It can be used as a standard reference value for the power grid, and the real-time angular frequency. This can be the current operating angular frequency of the power grid. The angular frequency difference detection stage measures the rated angular frequency. and real-time angular frequency The difference is calculated to determine the degree and direction of the power grid frequency deviation from steady state. The angular frequency difference output from the angular frequency difference detection circuit is then used to determine this deviation. As the input to the active frequency regulation coefficient stage, combined with the active frequency regulation coefficient and angular frequency difference Output primary frequency modulation power difference .

[0094] In the electromagnetic power feedback channel, the transient compensation electromagnetic power output by the first-order lead-lag element is used. Similarly, as feedback, the electromagnetic power of transient compensation will be... Active power reference value Primary frequency modulation power difference and electromagnetic power The power deviation signal is obtained by fusion.

[0095] Active power reference value Target active power set for grid-connected system scheduling or local control. Electromagnetic power. It is calculated based on the output voltage E of the power conversion circuit, the common coupling point voltage U of the power conversion circuit, and the equivalent impedance X between the power conversion circuit and the power grid.

[0096] In the electromagnetic power feedback channel, the transient lead and steady-state lag characteristics of the first-order lead-lag element are utilized to enable transient compensation of electromagnetic power. Damping compensation is provided only during the transient phase and approaches zero in steady state, thus decoupling damping control from active frequency regulation.

[0097] The power deviation signal is used as the input to the virtual inertia circuit. The virtual inertia simulates the inertial characteristics of the physical rotor of the synchronous generator, outputting the virtual speed change. The virtual speed change and the rated angular frequency are then compared. and real-time angular frequency of the power grid The power converter is fused, and the fusion result is integrated to output the power angle δ. The power angle δ reflects the phase difference between the output voltage of the power conversion circuit and the grid voltage. The controller can refer to the power angle δ to control the power converter, reducing the frequency deviation and frequency variation rate of the grid-connected system.

[0098] In the embodiments of this application, the electromagnetic power of the transient compensation output of the first-order lead-lag element is... The expression can be:

[0099] ;

[0100] in, Electromagnetic power for transient compensation; Electromagnetic power; It is the time constant of the first-order lead-lag element, used to adjust the dynamic response speed of the element, and can be designed in combination with the grid disturbance characteristics and power converter parameters; is the damping compensation coefficient, which directly determines the damping strength of transient compensation; s is the Laplace operator; It is the transfer function of a first-order lead-lag element.

[0101] A first-order lead-lag element is a dynamic correction circuit or algorithm module based on the Laplace transform. It utilizes the lead and lag frequency characteristics to compensate for transient electromagnetic power. It only works during transient phases such as sudden changes in grid frequency and automatically decays in steady state, thereby decoupling damping control from active power frequency regulation. This ensures that transient oscillations are quickly suppressed without affecting the steady-state power regulation accuracy of the active power loop.

[0102] Through the damping compensation coefficient Time constant of the first-order lead-lag element The synergistic effect of these factors increases the electromagnetic power of transient compensation. It becomes a transient quantity positively correlated with the rate of change of frequency (the differential characteristic characterized by s), thereby rapidly providing damping torque during frequency abrupt changes and suppressing power oscillations.

[0103] To further quantify the control characteristics of this scheme from a theoretical perspective, the transfer function of the active power loop with added first-order lead-lag elements can be expressed as:

[0104] ;

[0105] in, This is a reference value for active power. Electromagnetic power, The time constant of the first-order lead-lag element. Here, is the damping compensation coefficient, s is the Laplace operator, and J is the virtual inertia of the power conversion circuit. This represents the active frequency modulation coefficient of the power conversion circuit. The rated angular frequency is denoted by K, which is the power transfer coefficient, K=EU / X. E is the output voltage of the power conversion circuit, U is the common coupling point voltage of the power conversion circuit, and X is the equivalent impedance between the power conversion circuit and the power grid.

[0106] The transfer function of the active power loop with added first-order lead-lag elements describes the active power reference value. With electromagnetic power The dynamic relationship between them. This transfer function integrates the synergistic effect of virtual inertia, active frequency modulation, damping compensation, and lead-lag elements from the perspective of the complex frequency domain. Through the characteristics of a third-order system, it demonstrates the decoupling optimization between transient damping and steady-state frequency modulation in the embodiments of this application, providing a theoretical basis for subsequent system stability analysis (such as pole placement and damping ratio calculation).

[0107] To simplify the design of control parameters and ensure the dynamic characteristics of the system, the controller in this embodiment also uses the dominant pole method to reduce the order of the active loop third-order system after adding a first-order lead-lag element.

[0108] Specifically, the controller first establishes a mathematical model of the third-order system based on the active power loop transfer function and solves its characteristic equation to obtain three poles. Then, it selects the dominant pole with the smallest absolute value of the real part and ignores the non-dominant poles, approximating the third-order system as a second-order system with the dominant pole as the core. Finally, it verifies the effectiveness of the order reduction by comparing the step response of the third-order system with the reduced second-order system through simulation, thereby simplifying the design of control parameters while retaining the core dynamic characteristics.

[0109] The transfer function of the reduced-order active power loop is:

[0110] .

[0111] In this embodiment, the controller can determine the damping compensation coefficient of the power conversion circuit based on the virtual inertia of the power conversion circuit and the active frequency modulation coefficient of the power conversion circuit.

[0112] The virtual inertia of a power converter is simulated through a control algorithm, similar to the inertia of the physical rotor of a traditional synchronous generator. It is not a physical entity, but rather a dynamic characteristic achieved through mathematical models and control strategies. The main function of virtual inertia is to buffer rapid changes in grid frequency. When power disturbances occur in the grid, a larger virtual inertia can reduce the rate of frequency change, buying time for subsequent frequency regulation control and thus improving the stability of the grid-connected system.

[0113] The active power frequency regulation coefficient of a power converter is a proportional coefficient that measures the power converter's ability to participate in grid frequency regulation. The active power frequency regulation coefficient defines the amount of active power the power converter should generate or decrease per unit frequency deviation. When the grid frequency deviates from its rated value, the active power frequency regulation coefficient determines the frequency regulation capability of the power converter. A larger active power frequency regulation coefficient means that, for the same frequency deviation, the change in active power output by the power converter is greater, and the frequency recovery speed is faster, which helps maintain the steady-state frequency accuracy of the system.

[0114] The damping compensation coefficient comprehensively reflects the grid-connected system's ability to suppress power oscillations. It is used to establish the correlation between virtual inertia and active power frequency regulation coefficients. The damping compensation coefficient directly affects the damping effect provided by subsequent first-order lead-lag elements, thus determining the grid-connected system's ability to suppress dynamic oscillations.

[0115] The controller can obtain the virtual inertia and active power frequency regulation coefficient of the power converter from preset parameter configurations, or it can determine the virtual inertia and active power frequency regulation coefficient of the power converter based on the parameters of the grid-connected system. After obtaining the virtual inertia and active power frequency regulation coefficient of the power converter, the controller determines the damping compensation coefficient according to a preset algorithm, so that the grid-connected system can effectively suppress oscillations and ensure good steady-state performance.

[0116] Specifically, the controller can determine the damping compensation coefficient based on the virtual inertia, all power frequency modulation coefficients, damping ratio, and the time constant of the first-order lead-lag element. The expression for the damping compensation coefficient can be:

[0117] ;

[0118] in, This is the damping compensation coefficient. Where is the damping ratio, and J is the virtual inertia of the power conversion circuit. The active frequency modulation coefficient of the power conversion circuit is denoted as . Where ω is the rated angular frequency; K is the power transfer coefficient, K=EU / X, E is the output voltage of the power conversion circuit, U is the common coupling point voltage of the power conversion circuit, and X is the equivalent impedance between the power conversion circuit and the power grid.

[0119] The damping ratio is an indicator for measuring the dynamic oscillation characteristics of a system. The larger the damping ratio, the weaker the system oscillation and the more stable the dynamic response. This parameter provides a dynamic characteristic target for the design of the damping compensation coefficient.

[0120] The expression for the damping compensation coefficient is mathematically derived, linking core control parameters such as virtual inertia, active power frequency regulation coefficient, and damping ratio with the damping compensation coefficient. This achieves precise matching between the damping compensation strength and the system's dynamic characteristics. In practical applications, the controller can calculate an appropriate damping compensation coefficient based on the grid's requirements for dynamic oscillations and steady-state frequency regulation, combined with hardware parameters such as virtual inertia and power transmission coefficient. This provides a crucial damping strength reference for the first-order lead-lag element, thereby rapidly suppressing oscillations during transient states by superimposing transient compensation electromagnetic power, and ensuring the accuracy of active power frequency regulation is not interfered with during steady states. Ultimately, this achieves decoupling optimization of damping control and active power frequency regulation.

[0121] This application provides a schematic diagram illustrating the calculation process for determining the damping compensation coefficient, as shown in the embodiment. Figure 3 As shown below, in conjunction with Figure 3The calculation process for determining the damping compensation coefficient is introduced.

[0122] To further adapt to the grid's demand for inertia support, in this embodiment, the controller can also determine the virtual inertia of the power conversion circuit based on the synchronous generator's inertia time constant, the minimum inertia of the grid-connected system under the safety constraints of the frequency change rate, and the capacity penetration rate.

[0123] Capacity penetration rate is the proportion of the installed capacity of power conversion circuits in the total grid capacity. It quantifies the scale weight of power converters in the grid and is used to determine the proportion that they should bear in inertia support, ensuring that inertia allocation matches the installed capacity.

[0124] The inertial time constant of a synchronous generator reflects a key parameter of the physical rotor inertial characteristics of a traditional synchronous generator. It demonstrates the synchronous generator's ability to buffer frequency changes during frequency disturbances and provides a traditional power supply side inertial reference for calculating the virtual inertia that needs to be added to the power conversion circuit.

[0125] The minimum inertia of a grid-connected system under frequency change rate safety constraints is a threshold determined by the power grid according to frequency regulation safety standards or operating procedures. This ensures that when the power grid experiences power disturbances, the frequency change rate will not exceed a range that endangers equipment or grid stability; it is the bottom-line indicator for system inertia requirements. Frequency change rate safety constraints are the limitations imposed by the power system on the magnitude of frequency change per unit time to ensure equipment safety and stable grid operation. In a power system, the grid frequency changes when power disturbances occur. If the frequency change rate is too large, it can damage generators, electrical equipment, and even cause grid instability. In this embodiment, the virtual inertia of the power conversion circuit is determined by considering the minimum inertia of the grid-connected system under frequency change rate safety constraints, combined with the inertial time constant and capacity penetration rate of the synchronous generator. The aim is to ensure that the frequency change rate of the power grid does not exceed a safe range when subjected to power disturbances, thereby ensuring the stable operation of the power grid.

[0126] The inertial time constant of a synchronous generator defines the inherent inertia benchmark of traditional power sources, providing a basis for calculating the grid inertia gap. The minimum inertia of the grid-connected system under the frequency change rate safety constraint defines the inertia baseline required for stable grid operation, ensuring that frequency disturbances do not exceed the safety threshold. The capacity penetration rate quantifies the scale weight of the power conversion circuit in the grid, clarifying its proportion of inertia supplementation. The combination of these three factors allows the virtual inertia configuration of the power conversion circuit to both compensate for the inertia deficiency of traditional power sources and meet system safety requirements, while also matching its own installed capacity, achieving grid inertia balance and stable operation. The controller determines the virtual inertia of the power conversion circuit by integrating the above parameters, enabling the power conversion circuit to simulate the inertial characteristics of a synchronous generator, supplement grid inertia, meet the frequency change rate safety constraint, and improve grid transient stability.

[0127] Specifically, the controller is used to determine the virtual inertia of the power conversion circuit according to the following formula:

[0128] ;

[0129] in, This represents the minimum virtual inertia of the power conversion circuit. The minimum inertia of the grid-connected system under the safety constraint of the rate of change of frequency. The inertial time constant of the synchronous generator. This refers to capacity penetration rate.

[0130] The controller integrates the minimum inertia requirement of the grid-connected system, the inertia time constant of the synchronous generator, and the installed capacity ratio of the power conversion circuit to quantitatively calculate the minimum virtual inertia that the power conversion circuit needs to provide. This ensures that while making up for the insufficiency of traditional inertia, it matches the installed capacity and meets the safety constraints of the grid frequency change rate, thereby achieving precise inertia configuration and stable system operation.

[0131] To further clarify the quantitative basis for the minimum inertia of the system under the safety constraint of the rate of frequency change, in the embodiments of this application, the controller can also determine the minimum inertia based on the maximum value of the rate of frequency change and the maximum value of the disturbance power of the regional grid-connected system.

[0132] Specifically, the controller can determine the minimum inertia using the following formula:

[0133] ;

[0134] in, The maximum value of the rate of change of frequency is the safe threshold for the rate of change of frequency. The disturbance power of the regional power grid system can be estimated in advance based on system operating conditions and historical data. .

[0135] Based on the physical relationship between the power system inertia and the maximum rate of frequency change, the controller derives the minimum inertia to ensure system safety by using the maximum rate of frequency change and the maximum disturbance power that may occur in the regional grid-connected system.

[0136] In addition to the precise configuration of virtual inertia, the active power frequency regulation coefficient, as a core parameter to ensure the steady-state frequency accuracy of the system, also needs to be deeply adapted to the characteristics of the power grid. In the embodiments of this application, the controller can also determine the active power frequency regulation coefficient of the power conversion circuit based on the minimum value of the active power frequency regulation coefficient of the grid-connected system, the inertial time constant of the synchronous generator, and the capacity penetration rate.

[0137] Specifically, the controller is used to determine the active frequency regulation coefficient of the power conversion circuit according to the following formula:

[0138] ;

[0139] in, This represents the active frequency modulation coefficient of the power conversion circuit; This represents the minimum active power frequency regulation coefficient of the grid-connected system, signifying the minimum requirement for the system's steady-state frequency accuracy. The active frequency regulation coefficient of a synchronous generator reflects the frequency regulation capability of a traditional power source. This refers to capacity penetration rate.

[0140] The controller first calculates the synchronous generator's capacity percentage and then deducts the percentage of its own capacity. The subsequent contribution to the system's active frequency regulation coefficient Then use the minimum active power frequency regulation coefficient required by the grid-connected system. Subtracting this contribution yields the frequency modulation gap that the power conversion circuit needs to handle, and finally, dividing by the capacity penetration rate. This allows us to determine the active power frequency modulation coefficient that the power conversion circuit should be configured with. This approach ensures both the overall steady-state frequency regulation accuracy of the system and matches the frequency regulation responsibility of the power conversion circuit with its installed capacity, achieving a reasonable allocation of active power frequency regulation capability between the traditional power supply and the power conversion circuit.

[0141] In this embodiment of the application, the minimum value of the active frequency modulation coefficient It can be determined based on the steady-state frequency deviation range of the grid-connected system and the maximum disturbance power of the regional grid-connected system.

[0142] In the steady-state phase following a system disturbance, the system frequency remains essentially constant, and the disturbance power... Minimum active power frequency regulation coefficient under steady-state frequency deviation constraints, achieved solely by balancing the primary frequency regulation power of synchronous generators and grid-connected power units. It can be represented as:

[0143] ;

[0144] in, The maximum disturbance power of the regional grid-connected system refers to the power gap or surplus of the power grid under extreme operating conditions (such as sudden changes in maximum load or fluctuations in the maximum output of new energy sources), which is the maximum order of magnitude of frequency regulation demand; The steady-state frequency deviation range of the grid-connected system represents the grid's requirement for steady-state frequency accuracy and signifies the safe threshold for frequency deviation.

[0145] In the steady-state phase following a system disturbance, the frequency remains essentially constant, and the disturbance power is balanced by the primary frequency regulation power of the synchronous generator sets and grid-connected power sources. Based on the physical meaning of the active power frequency regulation coefficient (the amount of active power adjustment corresponding to a unit frequency deviation), to ensure maximum disturbance power... Below, the steady-state frequency deviation does not exceed , must meet Therefore, the minimum value of the above active frequency modulation coefficient is derived. The expression quantifies the relationship between the system's steady-state frequency modulation accuracy requirements and the maximum disturbance power, providing a fundamental safety basis for configuring the active power frequency modulation coefficient of the power conversion circuit.

[0146] Based on the power converter described in the above embodiments, this application also provides a control method for the power converter, the method comprising:

[0147] The damping compensation coefficient of the power conversion circuit is determined based on the virtual inertia of the power conversion circuit and the active frequency modulation coefficient of the power conversion circuit.

[0148] A first-order lead-lag element is added to the electromagnetic power feedback channel in the active loop of the power conversion circuit to decouple the damping control link and the active frequency modulation link of the power conversion circuit; the first-order lead-lag element uses the damping compensation coefficient to superimpose the transient compensation electromagnetic power of the output of the electromagnetic power feedback channel.

[0149] In one possible implementation, the method further includes determining the virtual inertia of the power conversion circuit based on the synchronous generator's inertial time constant, the minimum inertia of the grid-connected system under the frequency change rate safety constraint, and the capacity penetration rate; the capacity penetration rate is the proportion of the installed capacity of the power conversion circuit to the total grid capacity.

[0150] In one possible implementation, the method further includes determining the minimum inertia based on the maximum value of the rate of change of frequency and the maximum value of the disturbance power of the regional grid-connected system.

[0151] In one possible implementation, the method further includes determining the active frequency regulation coefficient of the power conversion circuit based on the minimum active frequency regulation coefficient of the grid-connected system, the active frequency regulation coefficient of the synchronous generator, and the capacity penetration rate.

[0152] In one possible implementation, the method further includes determining the minimum value of the active frequency regulation coefficient based on the steady-state frequency deviation range of the grid-connected system and the maximum disturbance power of the regional grid-connected system.

[0153] In one possible implementation, determining the damping compensation coefficient of the power conversion circuit based on the virtual inertia of the power conversion circuit and the active frequency modulation coefficient of the power conversion circuit includes: determining the damping compensation coefficient based on the virtual inertia, the active frequency modulation coefficient, the damping ratio, and the time constant of the first-order lead-lag element.

[0154] In one possible implementation, the method further includes using the dominant pole method to reduce the order of the active power loop after adding a first-order lead-lag element.

[0155] In one possible implementation, when the power conversion circuit is in a steady state, the transient compensation electromagnetic power in the first-order lead-lag element is zero.

[0156] When the power conversion circuit is in steady state, the electromagnetic power of transient compensation in the first-order lead-lag element is zero.

[0157] In one possible implementation, the expression for the electromagnetic power of the transient compensation is:

[0158] ;

[0159] in, The electromagnetic power for the transient compensation, Electromagnetic power, Let be the time constant of the first-order lead-lag element. Let be the damping compensation coefficient, and s be the Laplace operator. It is the transfer function of a first-order lead-lag element.

[0160] In one possible implementation, the transfer function of the active power loop with the added first-order lead-lag element is:

[0161] ;

[0162] in, This is a reference value for active power. Electromagnetic power, Let be the time constant of the first-order lead-lag element. Here, s is the damping compensation coefficient, s is the Laplace operator, and J is the virtual inertia of the power conversion circuit. The active frequency modulation coefficient of the power conversion circuit is denoted as . The rated angular frequency is K = EU / X, where E is the output voltage of the power conversion circuit, U is the common coupling point voltage of the power conversion circuit, and X is the equivalent impedance between the power conversion circuit and the power grid.

[0163] In one possible implementation, the transfer function of the reduced-order active power loop is:

[0164] .

[0165] In one possible implementation, the controller is used to determine the virtual inertia of the power conversion circuit according to the following formula:

[0166] ;

[0167] in, This represents the minimum virtual inertia of the power conversion circuit. The minimum inertia of the grid-connected system under the safety constraint of the rate of change of frequency is given. The inertial time constant of the synchronous generator is... The capacity permeability is denoted as .

[0168] In one possible implementation, the controller is used to determine the active frequency modulation coefficient of the power conversion circuit according to the following formula:

[0169] ;

[0170] in, The active frequency modulation coefficient of the power conversion circuit is denoted as . This represents the minimum active power frequency regulation coefficient of the grid-connected system. The active power frequency regulation coefficient of the synchronous generator is denoted as . The capacity permeability is denoted as .

[0171] In one possible implementation, the expression for the damping compensation coefficient is:

[0172] ;

[0173] in, The damping compensation coefficient is... Where J is the damping ratio, and J is the virtual inertia of the power conversion circuit. The active frequency modulation coefficient of the power conversion circuit is denoted as . The rated angular frequency is K = EU / X, where E is the output voltage of the power conversion circuit, U is the common coupling point voltage of the power conversion circuit, and X is the equivalent impedance between the power conversion circuit and the power grid.

[0174] This application also provides a control device. The control device may include a memory and a processor. The processor is used to execute the control method of the power converter described in any of the above embodiments. The memory may be random access memory (RAM), flash memory, read-only memory (ROM), non-volatile read-only memory (EPROM), registers, hard disk, removable disk, etc.

[0175] Memory can store computer instructions, which, when executed by the processor, can be used to implement control methods for the power converter. Memory can also store data.

[0176] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape) or a semiconductor medium (e.g., solid-state disk (SSD)).

[0177] This application also provides a readable storage medium for storing the methods provided in the above embodiments. For example, RAM, flash memory, ROM, EPROM, registers, hard disk, removable disk, or any other form of storage medium in the art.

[0178] In the embodiments of this application, the terms "first" and "second" (if they exist) are used only as name identifiers and do not represent the order of first and second.

[0179] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Regarding the methods disclosed in the embodiments, since they correspond to the product embodiments disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the description of the product embodiments.

[0180] 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 power converter for frequency support, characterized in that, The power converter includes a power conversion circuit and a controller; The first terminal of the power conversion circuit is connected to the power grid, and the second terminal of the power conversion circuit is connected to the power source; the synchronous generator is connected to the power grid. The controller is used to determine the damping compensation coefficient of the power conversion circuit based on the virtual inertia of the power conversion circuit and the active frequency regulation coefficient of the power conversion circuit; to add a first-order lead-lag element to the electromagnetic power feedback channel in the active loop of the power conversion circuit, thereby decoupling the damping control element and the active frequency regulation element of the power conversion circuit; and to use the damping compensation coefficient to superimpose transiently compensated electromagnetic power on the output of the electromagnetic power feedback channel in the first-order lead-lag element.

2. The power converter according to claim 1, characterized in that, The controller is further configured to determine the virtual inertia of the power conversion circuit based on the inertial time constant of the synchronous generator, the minimum inertia of the grid-connected system under the safety constraints of the frequency change rate, and the capacity penetration rate; the capacity penetration rate is the proportion of the installed capacity of the power conversion circuit to the total grid capacity.

3. The power converter according to claim 2, characterized in that, The controller is also configured to determine the minimum inertia based on the maximum value of the frequency change rate and the maximum value of the disturbance power of the regional grid-connected system.

4. The power converter according to claim 1, characterized in that, The controller is also used to determine the active frequency regulation coefficient of the power conversion circuit based on the minimum active frequency regulation coefficient of the grid-connected system, the active frequency regulation coefficient of the synchronous generator, and the capacity penetration rate.

5. The power converter according to claim 4, characterized in that, The controller is also used to determine the minimum value of the active frequency regulation coefficient based on the steady-state frequency deviation range of the grid-connected system and the maximum disturbance power of the regional grid-connected system.

6. The power converter according to claim 1, characterized in that, The controller is specifically used to determine the damping compensation coefficient based on the virtual inertia, the active frequency modulation coefficient, the damping ratio, and the time constant of the first-order lead-lag element.

7. The power converter according to claim 1, characterized in that, The controller is also used to reduce the order of the active power loop after adding a first-order lead-lag element using the dominant pole method.

8. The power converter according to claim 1, characterized in that, When the power conversion circuit is in steady state, the electromagnetic power of transient compensation in the first-order lead-lag element is zero.

9. The power converter according to claim 1, characterized in that, The expression for the electromagnetic power of the transient compensation is: ； in, The electromagnetic power for the transient compensation, Electromagnetic power, Let be the time constant of the first-order lead-lag element. Let be the damping compensation coefficient, and s be the Laplace operator. It is the transfer function of a first-order lead-lag element.

10. The power converter according to claim 1, characterized in that, The transfer function of the active power loop with an added first-order lead-lag element is: ； in, This is a reference value for active power. Electromagnetic power, Let be the time constant of the first-order lead-lag element. Here, s is the damping compensation coefficient, s is the Laplace operator, and J is the virtual inertia of the power conversion circuit. The active frequency modulation coefficient of the power conversion circuit is denoted as . The rated angular frequency is K = EU / X, where E is the output voltage of the power conversion circuit, U is the common coupling point voltage of the power conversion circuit, and X is the equivalent impedance between the power conversion circuit and the power grid.

11. The power converter according to claim 1, characterized in that, The transfer function of the reduced-order active power loop is: 。 12. The power converter according to claim 2, characterized in that, The controller is used to determine the virtual inertia of the power conversion circuit according to the following formula: ； in, This represents the minimum virtual inertia of the power conversion circuit. The minimum inertia of the grid-connected system under the safety constraint of the rate of change of frequency is given. Let be the inertial time constant of the synchronous generator. The capacity permeability is denoted as .

13. The power converter according to claim 4, characterized in that, The controller is used to determine the active frequency modulation coefficient of the power conversion circuit according to the following formula: ； in, The active frequency modulation coefficient of the power conversion circuit is denoted as . This represents the minimum active power frequency regulation coefficient of the grid-connected system. The active power frequency regulation coefficient of the synchronous generator is denoted as . The capacity permeability is denoted as .

14. The power converter according to claim 1, characterized in that, The expression for the damping compensation coefficient is as follows: ； in, The damping compensation coefficient is... Where J is the damping ratio, and J is the virtual inertia of the power conversion circuit. The active frequency modulation coefficient of the power conversion circuit is denoted as . The rated angular frequency is K = EU / X, where E is the output voltage of the power conversion circuit, U is the common coupling point voltage of the power conversion circuit, and X is the equivalent impedance between the power conversion circuit and the power grid.

15. A control method for a power converter, characterized in that, The first end of the power converter is connected to the power grid, and the second end of the power converter is connected to the power source; the synchronous generator is connected to the power grid. The method includes: The damping compensation coefficient of the power conversion circuit is determined based on the virtual inertia of the power conversion circuit and the active frequency modulation coefficient of the power conversion circuit. A first-order lead-lag element is added to the electromagnetic power feedback channel in the active loop of the power conversion circuit to decouple the damping control link and the active frequency modulation link of the power conversion circuit; the first-order lead-lag element uses the damping compensation coefficient to superimpose the transient compensation electromagnetic power of the output of the electromagnetic power feedback channel.

16. A control device, characterized in that, It includes a processor and a memory, the memory being used to store programs, instructions, or code, and the processor being used to execute the programs, instructions, or code in the memory to perform the control method of the power converter as described in claim 15.

17. A computer-readable storage medium, characterized in that, The device contains a computer program that is loaded by a processor to execute the control method for the power converter as described in claim 15.

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