Virtual synchronous generator control method and device based on zero pole assignment, medium and product

Abstract

The invention discloses a control method of a virtual synchronous generator based on zero-pole assignment, equipment, a medium and a product, and relates to the technical field of new energy grid-connected converter control. Parameters of a proportional-integral controller, a feed-forward coefficient of an active power difference and a feed-forward coefficient of an active power set value difference are set; the zero point of the first active power transfer function is equal to the second pole of the active loop, and the zero point of the second active power transfer function is equal to the second pole of the active loop, so that the zero points are offset, and the first active power transfer function and the second active power transfer function are reduced into a first-order system, so that the parameter design is simpler; meanwhile, an active ring pole is determined through active customization adjustment time, then proportional-integral controller parameters are determined, a reactive ring integral coefficient is determined through reactive customization adjustment time, and therefore time can be customized flexibly.

Description

Technical Field

[0001] The present application relates to the technical field of new energy grid-connected converter control, and particularly to a control method, device, medium and product of a virtual synchronous generator based on zero-pole configuration. Background Technique

[0002] With the increasing penetration rate of new energy in the power system, the power system faces many problems such as decreased stability and reduced inertia. In this context, the virtual synchronous generator technology (VSG) has been widely applied in the power system by endowing the inverter power supply with the ability to simulate the inertia of a synchronous motor.

[0003] Existing VSG control methods are difficult to solve the problems of grid-connected power overshoot and difficult design of the regulation time. At present, some studies have established a small-signal model of VSG for analyzing and designing the power control loop, but its inertia time is not adjustable, and the optimal selection of parameters is only to ensure good dynamic performance. When using a dynamic model to add a low-pass filter to achieve inertia, the system will become a third-order system, making the parameter design complicated. At present, for the problem of grid-connected power overshoot, there is no control method that can meet both the requirements of simple parameter design and flexible customization of the regulation time. Summary of the Invention

[0004] The purpose of the present application is to provide a control method, device, medium and product of a virtual synchronous generator based on zero-pole configuration, which can meet both the requirements of simple parameter design and flexible customization of the regulation time.

[0005] To achieve the above purpose, the present application provides the following solutions: In the first aspect, the present application provides a control method of a virtual synchronous generator based on zero-pole configuration, including: Obtain voltage and current data and the customized regulation time of active power; the voltage and current data include: the output voltage on the converter side, the output current on the converter side, and the grid voltage; the customized regulation time includes: the customized regulation time of active power and the customized regulation time of reactive power; Combine the grid-connected power calculation formula, and determine the active power gain coefficient and the reactive power gain coefficient according to the output voltage on the converter side and the grid voltage; Determine the first pole of the active power loop and the second pole of the active power loop according to the customized regulation time of active power, the active power gain coefficient, and the steady-state output of active power; Determine the integral controller parameter and the proportional controller parameter according to the first pole of the active power loop, the second pole of the active power loop, and the active power gain coefficient; where, ; in the formula, represents the integral controller parameter, represents the proportional controller parameter,A represents the active power gain coefficient, p 1 represents the first pole of the active power loop, p 2 represents the second pole of the active power loop; Determine the feed - forward coefficient of the active power set value according to the first transfer function of active power: ; where, represents the feed - forward coefficient of the active power set value; represents the second pole of the active power loop; ; in the formula, represents the first pole of the active power loop; represents the steady - state output of active power when the system frequency changes by one hertz; the first transfer function of active power is a small - signal transfer function with the active power set value as the input; at this time, the zero point of the first transfer function of active power is equal to the second pole of the active power loop, and the first transfer function of active power is a first - order control system; Determine the feed - forward coefficient of the active power difference according to the second transfer function of active power: ; where, represents the feed - forward coefficient of the active power difference, represents the active power droop coefficient; the active power difference is the product of the angular frequency difference and the active power droop coefficient; the angular frequency difference is the difference between the grid angular frequency and the rated angular frequency; the second transfer function of active power is a small - signal transfer function with the active power difference as the input; at this time, the zero point of the second transfer function of active power is equal to the second pole of the active power loop, and the second transfer function of active power is a first - order control system; Perform active power control on the active power and the active power set value according to the integral controller parameters, proportional controller parameters, the feed - forward coefficient of the active power set value, and the feed - forward coefficient of the active power difference to obtain the voltage phase angle of the converter; Determine the integral coefficient of the reactive power loop according to the reactive power regulation time and the reactive power gain coefficient; Perform reactive power control according to the integral coefficient of the reactive power loop, reactive power, reactive power set value, reactive power difference, and rated voltage to obtain the voltage amplitude of the converter; where, the reactive power difference is the product of the voltage difference and the reactive power droop coefficient; the voltage difference is the difference between the grid voltage and the rated voltage after the grid voltage changes; Perform voltage - current double - closed - loop control according to the output voltage on the converter side, the output current on the converter side, the voltage phase angle of the converter, and the voltage amplitude of the converter to obtain the voltage control amount of the converter; Generate the PWM signal of the converter according to the voltage control amount of the converter and the high - frequency triangular carrier signal.

[0006] Optionally, the active power gain coefficient: ; Among them, A represents the active power gain coefficient, U C represents the output voltage on the converter side, U g represents the grid voltage, X represents the reactance value between the converter and the grid side; The reactive power gain coefficient: ; Among them, B represents the reactive power gain coefficient.

[0007] Optionally, according to the integral controller parameter, the proportional controller parameter, the feed-forward coefficient of the active power setpoint, and the feed-forward coefficient of the active power difference, the formula for performing active power control on the active power and the active power setpoint to obtain the voltage phase angle of the converter is: ; Among them, represents the voltage phase angle, represents the integral controller parameter, represents the proportional controller parameter, S represents the grid-connected power, P ref represents the active power reference value, p represents the active power, represents the feed-forward coefficient of the active power setpoint; represents the feed-forward coefficient of the active power difference, represents the active power setpoint, P rd represents the active power difference, represents the rated angular frequency.

[0008] Optionally, according to the reactive power loop integral coefficient, the reactive power, the reactive power setpoint, the reactive power difference, and the rated voltage, the formula for obtaining the voltage amplitude of the converter is: ; Among them, represents the voltage amplitude of the converter, k iq represents the reactive power loop integral coefficient, q set represents the reactive power setpoint, q rd represents the reactive power difference, q represents the reactive power, U n represents the rated voltage.

[0009] Optionally, determine the first pole of the active power loop and the second pole of the active power loop according to the active power customization adjustment time, the active power gain coefficient, and the steady-state output of the active power, which specifically includes: Determine the first pole of the active power loop according to the active power customization adjustment time, and the formula is: ; Wherein, represents the active power customization adjustment time; Determine the second pole of the active power loop according to the active power gain coefficient, the steady-state output of the active power, and the first pole of the active power loop, and the formula is: ; Wherein, A represents the active power gain coefficient, represents the steady-state output of the active power when the system frequency changes by one hertz.

[0010] Optionally, the formula for determining the integral coefficient of the reactive power loop according to the reactive power customization adjustment time and the reactive power gain coefficient is: ; Wherein, represents the reactive power customization adjustment time, B represents the reactive power gain coefficient, k iq represents the integral coefficient of the reactive power loop.

[0011] Optionally, generate the PWM signal of the converter according to the voltage control amount of the converter and the high-frequency triangular carrier signal, which specifically includes: Convert the voltage control amount of the converter into the voltage control amount in the coordinate system to obtain the three-phase control amount; Compare the three-phase control amount with the high-frequency triangular carrier signal; when the three-phase control amount is greater than the high-frequency triangular carrier signal, the switching device of the converter is turned on; when the three-phase control amount is less than the high-frequency triangular carrier signal, the switching device of the converter is turned off, and the PWM signal of the converter is generated.

[0012] In a second aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor executes the computer program to implement the control method of the virtual synchronous generator based on zero-pole configuration described in any one of the above.

[0013] In a third aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the control method of the virtual synchronous generator based on zero-pole configuration described in any one of the above is implemented.

[0014] In a fourth aspect, the present application provides a computer program product, including a computer program which, when executed by a processor, implements the control method of the virtual synchronous generator based on zero-pole configuration described in any one of the above.

[0015] According to the specific embodiments provided by the present application, the following technical effects are disclosed in the present application: The present application provides a control method, device, medium and product of a virtual synchronous generator based on zero-pole configuration. The method includes: obtaining voltage and current data and active customization adjustment time; the voltage and current data includes: the converter-side output voltage, the converter-side output current and the grid voltage; the customization adjustment time includes: active customization adjustment time and reactive customization adjustment time; combining the grid-connected power calculation formula, determining the active gain coefficient and the reactive gain coefficient according to the converter-side output voltage and the grid voltage; determining the first pole of the active loop and the second pole of the active loop according to the active customization adjustment time, the active gain coefficient and the steady-state output of the active power; determining the integral controller parameter and the proportional controller parameter according to the first pole of the active loop, the second pole of the active loop and the active gain coefficient; where ; in the formula, represents the integral controller parameter, represents the proportional controller parameter, A represents the active gain coefficient, p 1 represents the first pole of the active loop, p 2 represents the second pole of the active loop; determining the feed-forward coefficient of the active set value according to the first transfer function of the active power: ; where represents the feed-forward coefficient of the active set value; represents the second pole of the active loop; ; in the formula, represents the first pole of the active loop; represents the steady-state output of the active power when the system frequency changes by one hertz; the first transfer function of the active power is a small-signal transfer function obtained with the active set value as the input; at this time, the zero point of the first transfer function of the active power is equal to the second pole of the active loop, and the first transfer function of the active power is a first-order control system; determining the feed-forward coefficient of the active difference according to the second transfer function of the active power: ; where represents the feed-forward coefficient of the active difference, represents the active droop coefficient; the active power difference is the product of the angular frequency difference and the active droop coefficient; the angular frequency difference is the difference between the grid angular frequency and the rated angular frequency; the second transfer function of the active power is a small-signal transfer function obtained with the active power difference as the input; at this time, the zero point of the second transfer function of the active power is equal to the second pole of the active power loop, and the second transfer function of the active power is a first-order control system; according to the integral controller parameter, the proportional controller parameter, the feed-forward coefficient of the active power set value, and the feed-forward coefficient of the active power difference, perform active power control on the active power and the active power set value to obtain the voltage phase angle of the converter; according to the reactive power customization adjustment time and the reactive power gain coefficient, determine the integral coefficient of the reactive power loop; according to the integral coefficient of the reactive power loop, the reactive power, the reactive power set value, the reactive power difference, and the rated voltage, perform reactive power control to obtain the voltage amplitude of the converter; wherein, the reactive power difference is the product of the voltage difference and the reactive droop coefficient; the voltage difference is the difference between the grid voltage and the rated voltage after the grid voltage changes; according to the output voltage on the converter side, the output current on the converter side, the voltage phase angle of the converter, and the voltage amplitude of the converter, perform voltage-current double closed-loop control to obtain the voltage control amount of the converter; according to the voltage control amount of the converter and the high-frequency triangular carrier signal, generate the PWM signal of the converter. In this application, by setting the proportional-integral controller parameters, the active power loop is reduced to a first-order system, so that its parameter design is simpler. At the same time, in this application, the poles of the active power loop are determined by the active power customization adjustment time, and then the proportional-integral controller parameters are determined. The integral coefficient of the reactive power loop is determined by the reactive power customization adjustment time, so that the time can be flexibly customized. In other words, the time is associated with the finally output control amount, and the control amount will also change after the time changes. Therefore, this application can meet the two requirements of simple parameter design and flexible customization of the adjustment time at the same time. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 It is an application environment diagram of a control method for a virtual synchronous generator based on zero-pole configuration in an embodiment of the present application.

[0018] Figure 2 It is a flow schematic diagram of a control method for a virtual synchronous generator based on zero-pole configuration provided by an embodiment of the present application.

[0019] Figure 3Schematic diagram of the VSG control process provided by an embodiment of the present application.

[0020] Figure 4 Schematic diagram of the grid connection of the VSG converter provided by an embodiment of the present application.

[0021] Figure 5 Schematic diagram of the active power control of the VSG provided by an embodiment of the present application.

[0022] Figure 6 Schematic diagram of the reactive power control of the VSG provided by an embodiment of the present application.

[0023] Figure 7 Schematic diagram of the simulation waveform of the sudden change of the reference values of the active power and the reactive power with a dynamic regulation time of 1 s provided by an embodiment of the present application.

[0024] Figure 8 Schematic diagram of the simulation waveform of the sudden change of the reference values of the active power and the reactive power with a dynamic regulation time of 0.2 s provided by an embodiment of the present application.

[0025] Figure 9 Schematic diagram of the simulation waveforms of the active power and the reactive power when the grid frequency suddenly changes by 1 Hz provided by an embodiment of the present application.

[0026] Figure 10 Schematic diagram of the simulation waveforms of the active power and the reactive power when the grid voltage suddenly changes by 5 V provided by an embodiment of the present application.

[0027] Figure 11 Schematic diagram of the simulation waveform of the robustness test when the grid voltage is 150 V provided by an embodiment of the present application.

[0028] Figure 12 Schematic diagram of the structure of a computer device provided by an embodiment of the present application. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0030] Existing VSG control methods are difficult to solve the problems of grid-connected power overshoot and difficult design of regulation time. Whether it is the VSG control that simulates the rotor swing equation or the droop control that introduces inertia through a low-pass filter, its essence makes the active power loop a second-order system. The reference value tracking performance and grid frequency dynamic response of the second-order system usually exhibit overshoot and oscillation. At the same time, the high coupling of the droop coefficient, inertia, and damping coefficient also brings inconvenience to the controller design.

[0031] What this application proposes is a virtual synchronous generator control method with flexible customizable regulation time and good transient and steady-state performance. It has good transient and steady-state performance to solve the problems of power overshoot, inflexible customizable regulation time, and difficult parameter design in the existing control methods.

[0032] To make the above objects, features, and advantages of this application more obvious and understandable, the following further details this application in conjunction with the drawings and specific embodiments.

[0033] The control method of the virtual synchronous generator based on zero-pole configuration provided by the embodiments of this application can be applied to, for example, Figure 1 the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set up separately, integrated on the server 104, or placed on the cloud or other servers. Among them, the terminal 102 can be, but is not limited to, various desktop computers, laptop computers, smartphones, tablet computers, Internet of Things devices, and portable wearable devices. The Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart in-vehicle devices, etc. The portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers, and can also be a cloud server.

[0034] In an exemplary embodiment, as Figure 2 shown, a control method of the virtual synchronous generator based on zero-pole configuration is provided. This method is executed by a computer device, specifically, it can be executed separately by a computer device such as a terminal or a server, or jointly executed by a terminal and a server. In the embodiments of this application, taking this method applied to Figure 1 the server 104 in as an example for explanation, it includes the following steps S1 to step S11. Among them: S1. Obtain voltage and current data and the customized regulation time for active power; the voltage and current data include: the output voltage on the converter side, the output current on the converter side, and the grid voltage; the customized regulation time includes: the customized regulation time for active power and the customized regulation time for reactive power.

[0035] Please refer toFigure 3 , the virtual synchronous generator in this embodiment includes: an inverter power supply, a converter, and a filter circuit. In this embodiment, the output voltage on the converter side of the VSG, , the output current , and the phase angle , the voltage at the grid outlet , and the phase angle , the grid angular frequency are obtained, so as to obtain the voltage on the converter side and the voltage difference between the grid side ( - ) and the phase angle difference between the converter side and the grid side .

[0036] S2. Combining with the grid-connected power calculation formula, determine the active gain coefficient and the reactive gain coefficient according to the output voltage on the converter side and the grid voltage.

[0037] Please refer to Figure 4 to Figure 4 illustrate the connection relationship between the inverter power supply, the converter, the filter circuit and the grid. After the VSG converter filters out the switching frequency harmonics through the filter, the VSG converter can be equivalent to a voltage source, and its terminal voltage is . It is connected to the grid through the grid-connected impedance , and the grid voltage is ; is the grid-connected power, is the active power, is the reactive power; is the phase angle at the converter outlet side, is the phase angle at the grid outlet side, is the converter switching signal generated in this embodiment, R g represents the grid-connected resistance, L g represents the grid-connected inductance, X g represents the grid-connected reactance, j represents the unit of imaginary number, represents the angular frequency.

[0038] Considering that when the grid-connected impedance satisfies is much greater than , the grid-connected power can be expressed by the following formula, where and are respectively the amplitudes of the converter terminal voltage and the grid voltage, is the phase angle difference between the converter terminal voltage and the grid voltage.

[0039] ; It can be obtained through this formula , .

[0040] Among them, A represents the active power gain coefficient, U C represents the output voltage on the converter side, U g represents the grid voltage, X represents the reactance value between the converter and the grid side, B represents the reactive power gain coefficient.

[0041] S3. Determine the first pole and the second pole of the active power loop according to the active power regulation time, the active power gain coefficient, and the steady-state output of the active power.

[0042] Please refer to Figure 5 , Figure 5 for the active power control process. Figure 5 where is the rated angular frequency, and are the grid angular frequency and the actual angular frequency respectively; is the grid angular frequency and the rated angular frequency difference; is the actual angular frequency and the rated angular frequency difference; and are the grid voltage amplitude and the rated voltage amplitude respectively; is the sum of the active droop coefficients; is the active power reference value, and are the active power set value and the active power difference respectively; and are the integral coefficient and the proportional coefficient of the active power loop respectively; is the phase angle output by the active power loop; and are the feed-forward coefficients of the active power set value and the active power difference respectively; is the power angle difference.

[0043] First, determine the active droop coefficient . Use to represent the steady-state output of the active power when the system frequency changes by one hertz. Then, subtract the grid angular frequency from the rated angular frequency , and multiply the result by the active droop coefficient to obtain the active power difference .

[0044] 。

[0045] Obtain the small-signal transfer function related to active power control. Using the active power setpoint as the input to obtain the first transfer function of active power ; using the difference between the grid angular frequency and the rated angular frequency as the input to obtain the second transfer function of active power 。

[0046] ; Among them, 、 are respectively 's two poles (the first pole of the active power loop and the second pole of the active power loop), is 's zero point; is 's zero point.

[0047] Determine the first pole of the active power loop. It can be determined without overshoot through the active power customization adjustment time . The active power customization adjustment time is generally given according to the actual engineering requirements. According to the general definition of the adjustment time, the first pole can be determined by the following formula : ; Among them, represents the active power customization adjustment time.

[0048] Determine the second pole of the active power loop according to the active power gain coefficient, the steady-state output of the active power, and the first pole of the active power loop. The formula is: ; Among them, A represents the active power gain coefficient, represents the steady-state output of the active power when the system frequency changes by one hertz.

[0049] S4. Determine the integral controller parameter and the proportional controller parameter according to the first pole of the active power loop, the second pole of the active power loop, and the active power gain coefficient; among them, ; in the formula, represents the integral controller parameter, represents the proportional controller parameter, A represents the active power gain coefficient,p 1 represents the first pole of the active power loop, p 2 represents the second pole of the active power loop.

[0050] and is used to achieve power tracking, grid frequency phase angle synchronization, and inertia support.

[0051] .

[0052] S5. Determine the feed - forward coefficient of the active power setpoint according to the first transfer function of active power: ; where represents the feed - forward coefficient of the active power setpoint; represents the second pole of the active power loop; ; in the formula, represents the first pole of the active power loop; represents the system frequency (in this embodiment, the system here is specifically a system such as Figure 4 this system, that is, a system where the inverter power supply is connected to the grid through a filter circuit after passing through a converter). When the system frequency changes by one hertz, the steady - state output of the active power (which can be directly obtained). The first transfer function of active power is a small - signal transfer function with the active power setpoint as the input; at this time, the zero point of the first transfer function of active power is equal to the second pole of the active power loop, and the first transfer function of active power is a first - order control system.

[0053] Determine the feed - forward coefficient of the active power setpoint . When it can make the first transfer function of active power control achieve zero - point and pole cancellation, so that the first transfer function of VSG active power is reduced to a first - order control system.

[0054] The feed - forward coefficient of the active power setpoint is determined by the following formula: ; where represents the feed - forward coefficient of the active power setpoint; represents the second pole of the active power loop; ; in the formula, represents the first pole of the active power loop; represents the steady - state output of the active power when the system frequency changes by one hertz.

[0055] Through the above parameter configuration, the first transfer function of active power is reduced to a first - order control system.

[0056] S6. Determine the feedforward coefficient of the active power difference according to the second transfer function of the active power: ; where represents the feedforward coefficient of the active power difference, represents the active power droop coefficient; the active power difference is the product of the angular frequency difference and the active power droop coefficient; the angular frequency difference is the difference between the grid angular frequency and the rated angular frequency (these two frequencies can be obtained through a phase-locked loop); the second transfer function of the active power is a small-signal transfer function with the active power difference as the input; at this time, the zero point of the second transfer function of the active power is equal to the second pole of the active power loop, and the second transfer function of the active power is a first-order control system.

[0057] Determine the active power difference of the feedforward coefficient . When can make the second transfer function of the active power achieve zero point and pole cancellation, so that the second transfer function of the VSG active power is reduced to a first-order control system.

[0058] The active power difference of the feedforward coefficient is determined by the following formula: ; where represents the feedforward coefficient of the active power difference, represents the active power droop coefficient.

[0059] Through the above parameter configuration, the second transfer function of the active power is reduced to a first-order control system.

[0060] The final reduced first-order control system is: .

[0061] S7. According to the integral controller parameters, proportional controller parameters, feedforward coefficient of the active power set value, and the feedforward coefficient of the active power difference, perform active power control on the active power and the active power set value to obtain the voltage phase angle of the converter.

[0062] In this embodiment, the active power and the active power set value are sent into the active power control to obtain the voltage phase angle of the VSG converter: ; where represents the voltage phase angle, Represents the integral controller parameter, Represents the proportional controller parameter, S Represents the grid-connected power, P ref Represents the active power reference value (in this embodiment, it is given according to the active power required by the load in the system. Whatever active power the load requires, the active power reference value is that value). P represents the active power, Represents the feed-forward coefficient of the active power setpoint; Represents the feed-forward coefficient of the active power difference, Represents the active power setpoint, P rd Represents the active power difference, Represents the rated angular frequency.

[0063] S8. Determine the reactive power loop integral coefficient according to the reactive power customization adjustment time and the reactive power gain coefficient.

[0064] Please refer to Figure 6 , which is the reactive power control block diagram, Is the voltage amplitude output by the reactive power loop, Is the output voltage amplitude And the amplitude difference between it and the grid voltage ; Is the grid voltage And the rated voltage Of the amplitude difference; Reactive power droop coefficient; And Are the reactive power setpoint and the reactive power difference respectively; Is the integral coefficient of the reactive power loop.

[0065] Determine the reactive power droop coefficient . After the reactive power droop coefficient changes according to the grid voltage, the reactive power generated by the system is determined as follows. Then, the grid voltage Is subtracted from the rated voltage And multiplied by the reactive power droop coefficient To obtain the reactive power difference .

[0066] ; Where, Δ Q Represents the reactive power required for a unit voltage change, Δ U max Represents the range of voltage change allowed by the grid.

[0067] Customize the reactive power customization adjustment time. By adjusting Determine its reactive power customization adjustment time : ; Among them, represents the reactive power customization adjustment time that can be flexibly customized when the reactive power changes, B represents the reactive power gain coefficient, k iq represents the reactive power loop integral coefficient.

[0068] S9. According to the reactive power loop integral coefficient, reactive power, reactive power set value, reactive power difference, and rated voltage, perform reactive power control to obtain the voltage amplitude of the converter; among them, the reactive power difference is the product of the voltage difference and the reactive power droop coefficient; the voltage difference is the difference between the grid voltage and the rated voltage after the grid voltage changes.

[0069] In this embodiment, the reactive power and the reactive power set value are used to obtain the voltage amplitude of the VSG converter: ; Among them, represents the voltage amplitude of the converter, k iq represents the reactive power loop integral coefficient, q set represents the reactive power set value, q rd represents the reactive power difference, q represents the reactive power, U n represents the rated voltage.

[0070] S10. According to the output voltage on the converter side, the output current on the converter side, the voltage phase angle of the converter, and the voltage amplitude of the converter, perform voltage-current double closed-loop control to obtain the voltage control amount of the converter.

[0071] In this embodiment, after the collected output voltage and output current signals are subjected to Park transformation, the output voltage and output current of the converter in the dq coordinate system are obtained.

[0072] According to the output voltage and output current of the converter in the dq coordinate system, as well as the voltage amplitude and voltage phase angle of the VSG converter, perform voltage-current double closed-loop control to obtain the voltage control amounts and of the VSG converter in the dq coordinate system.

[0073] S11. Generate the PWM signal of the converter based on the voltage control quantity of the converter and the high-frequency triangular carrier signal.

[0074] Based on the obtained voltage control quantity of the VSG converter in the dq coordinate system and perform the Park inverse transformation to obtain the voltage control quantity in the coordinate system (three-phase control quantity).

[0075] Compare the three-phase control quantity with the high-frequency triangular carrier signal; when the three-phase control quantity is greater than the high-frequency triangular carrier signal, the converter switching device is turned on; when the three-phase control quantity is less than the high-frequency triangular carrier signal, the converter switching device is turned off to generate the PWM signal of the converter.

[0076] Generally speaking, in this application, by setting the parameters of the proportional-integral controller, the feed-forward coefficient of the active power difference, and the feed-forward coefficient of the active power set value difference, the zero point of the first transfer function of the active power is made equal to the second pole of the active power loop, and the zero point of the second transfer function of the active power is made equal to the second pole of the active power loop, so as to cancel each other out, and the first transfer function of the active power and the second transfer function of the active power are respectively reduced to a first-order system, making its parameter design simpler. At the same time, in this application, the active power loop pole is determined through the active power customization adjustment time, and then the proportional-integral controller parameters are determined, and the reactive power loop integral coefficient is determined through the reactive power customization adjustment time, so that the time can be flexibly customized.

[0077] In this embodiment, , , , are the adjustment factors designed for this embodiment, and the functions are as follows.

[0078] First, by adjusting and values, the VSG active control loop can be effectively reduced from a second-order system to a first-order system, and then the control goal of no overshoot of power output can be achieved.

[0079] Second, combined with the diverse dynamic response requirements in engineering practice, the , values can be flexibly configured to achieve the customized design of the system adjustment time , , ensuring that the dynamic response performance of the VSG system meets the time index requirements of the specific application scenario.

[0080] This embodiment proposes a control method for a virtual synchronous generator based on zero-pole configuration. Through reasonable zero-pole configuration, this control strategy has excellent transient and steady-state performance when the grid-connected power of the VSG undergoes a sudden change. At the same time, the control parameters can be flexibly designed and dynamically adjusted according to the actual adjustment time requirements, improving the applicability and reliability of the VSG control strategy. Its unique features are: Design a proportional-integral droop controller on the traditional VSG control strategy to alleviate the adjustment contradiction between the droop coefficient and the damping coefficient.

[0081] The proposed new control structure adopts a feed-forward control loop, thus reducing the traditional second-order VSG control to a first-order control, enabling the system to meet the function requirement of no overshoot under different working scenarios.

[0082] Through reasonable zero-pole configuration, on the premise of ensuring no overshoot in the system response, flexible customization of the response time is achieved, so as to adapt to the different response time requirements in different scenarios.

[0083] In addition, to verify the effectiveness of this application, this embodiment also builds a system for a single VSG converter to operate in parallel with the grid. The simulation parameters and control parameter configurations are shown in Tables 1 and 2, and it operates under 3 different working conditions respectively to prove the effectiveness of the control strategy of this embodiment.

[0084]

[0085] Table 2 Control Parameters

[0086] Condition 1: The system power reference value undergoes a sudden change. Figure 7 The following shows the simulation waveforms of the sudden change of the active power and reactive power reference values with a dynamic adjustment time of 1 s. The active power and reactive power reference values suddenly increase by 5 kW (5 kVar) at 2 s and recover at 3.5 s. From Figure 7 it can be seen that the dynamic adjustment times are all 1 s and there is no overshoot in the dynamic process, which is consistent with the theoretical design results. The waveform of the reference value sudden change with a dynamic adjustment time of 0.2 s is as shown in Figure 8 the following.

[0087] Condition 2: When a small disturbance occurs in the power grid. Figure 9 The following shows the simulation waveforms of the active power and reactive power when the grid frequency suddenly changes by 1 Hz. From Figure 9 it can be seen that when the grid frequency suddenly increases / decreases, the grid-forming inverter can autonomously reduce / increase the times of active power, and there is no overshoot in the dynamic process, realizing the function of supporting the grid frequency. Figure 10 The following shows the simulation waveforms of the active power and reactive power when the grid voltage suddenly changes by 5 V. The inverter responds to the change of the grid voltage and autonomously reduces / increases the generation Multi-reactive power realizes the function of reactive power droop.

[0088] Condition 3: When a large disturbance occurs in the power grid. Figure 11 The following shows the simulation waveforms of the robustness test when the grid voltage drops to 150V and the dynamic regulation time is set to 0.5s. From Figure 11 it can be seen that the active power waveform only has a slight overshoot and the regulation time is still 0.5s. The reactive power waveform still shows the response characteristics of a first-order system, indicating that the proposed power control strategy has a certain degree of robustness.

[0089] In this embodiment, a control method for a virtual synchronous generator based on zero-pole configuration is designed. By introducing a feed-forward coefficient into the active power control loop of the VSG and , the zero-poles can be freely configured. Through the reasonable configuration of the zero-poles, the traditional VSG control strategy is reduced to a first-order control system, thus realizing that the dynamic regulation time can be flexibly customized and the system overshoot is eliminated. In addition, the change of the droop coefficient does not affect the dynamic performance of power control, and the dynamic performance of reactive power control can be flexibly adjusted through . This strategy provides a strong guarantee for the stable operation of the VSG grid-connected mode and meets the actual requirements for the regulation time in different engineering application scenarios.

[0090] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as Figure 12 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it realizes a control method for a virtual synchronous generator based on zero-pole configuration.

[0091] Those skilled in the art can understand, Figure 12The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0092] In an exemplary embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0093] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0094] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0095] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0096] Those of ordinary skill in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0097] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0098] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0099] In this article, specific examples are used to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A control method for a virtual synchronous generator based on zero-pole configuration, characterized in that, Including: Obtaining voltage and current data and the active custom regulation time; The voltage and current data includes: the converter side output voltage, the converter side output current, and the grid voltage; the custom regulation time includes: the active custom regulation time and the reactive custom regulation time; Combining with the grid-connected power calculation formula, determining the active gain coefficient and the reactive gain coefficient according to the converter side output voltage and the grid voltage; Determining the first pole and the second pole of the active loop according to the active custom regulation time, the active gain coefficient, and the steady-state output of the active power; Determine the integral controller parameter and the proportional controller parameter according to the first pole of the active loop, the second pole of the active loop, and the active gain coefficient; where, ; In the formula, represents the integral controller parameter, represents the proportional controller parameter, A represents the active gain coefficient, p 1 represents the first pole of the active loop, p 2 represents the second pole of the active loop; Determine the feedforward coefficient of the active power setpoint according to the first transfer function of the active power: ; where represents the feedforward coefficient of the active power setpoint; represents the second pole of the active power loop; ; in the formula represents the first pole of the active power loop; represents the steady-state output of the active power when the system frequency changes by one hertz; the first transfer function of the active power is a small-signal transfer function obtained with the active power setpoint as the input; at this time, the zero point of the first transfer function of the active power is equal to the second pole of the active power loop, and the first transfer function of the active power is a first-order control system; Determine the feedforward coefficient of the active power difference according to the second transfer function of the active power: ; where represents the feedforward coefficient of the active power difference, represents the active power droop coefficient; the active power difference is the product of the angular frequency difference and the active power droop coefficient; the angular frequency difference is the difference between the grid angular frequency and the rated angular frequency; the second transfer function of the active power is a small-signal transfer function obtained with the active power difference as the input; at this time, the zero point of the second transfer function of the active power is equal to the second pole of the active power loop, and the second transfer function of the active power is a first-order control system; According to the integral controller parameter, the proportional controller parameter, the feed-forward coefficient of the active set value, and the feed-forward coefficient of the active power difference, performing active power control on the active power and the active set value to obtain the voltage phase angle of the converter; Determining the integral coefficient of the reactive loop according to the reactive custom regulation time and the reactive gain coefficient; According to the integral coefficient of the reactive loop, the reactive power, the reactive power set value, the reactive power difference, and the rated voltage, performing reactive power control to obtain the voltage amplitude of the converter; wherein, the reactive power difference is the product of the voltage difference and the reactive droop coefficient; the voltage difference is the difference between the grid voltage and the rated voltage after the grid voltage changes; According to the converter side output voltage, the converter side output current, the voltage phase angle of the converter, and the voltage amplitude of the converter, performing voltage and current double closed-loop control to obtain the voltage control amount of the converter; Generating the PWM signal of the converter according to the voltage control amount of the converter and the high-frequency triangular carrier signal.

2. The control method of the virtual synchronous generator based on zero-pole configuration according to claim 1, characterized in that The active gain coefficient: ； Among them, A represents the active power gain coefficient, U C represents the output voltage on the converter side, U g represents the grid voltage, X represents the reactance value between the converter and the grid side; The reactive gain coefficient: ； Among them, B represents the reactive power gain coefficient.

3. The control method of the virtual synchronous generator based on zero-pole configuration according to claim 1, characterized in that, According to the integral controller parameter, the proportional controller parameter, the feed-forward coefficient of the active set value, and the feed-forward coefficient of the active power difference, the formula for performing active power control on the active power and the active set value to obtain the voltage phase angle of the converter is: ； Among them, represents the voltage phase angle, represents the integral controller parameter, represents the proportional controller parameter, S represents the grid-connected power, P ref represents the active reference value, p represents the active power, represents the feed-forward coefficient of the active set value; represents the feed-forward coefficient of the active difference, represents the active set value, P rd represents the active difference, represents the rated angular frequency.

4. The control method of the virtual synchronous generator based on zero-pole configuration according to claim 1, characterized in that According to the integral coefficient of the reactive loop, the reactive power, the reactive power set value, the reactive power difference, and the rated voltage, the formula for obtaining the voltage amplitude of the converter is: ； Among them, represents the voltage amplitude of the converter,[ k iq represents the integral coefficient of the reactive power loop,[ q set represents the reactive power setpoint,[ q rd represents the reactive power difference,[ q represents the reactive power,[ U n represents the rated voltage.[ 5. The control method of the virtual synchronous generator based on zero-pole configuration according to claim 1, characterized in that Determining the first pole and the second pole of the active loop according to the active custom regulation time, the active gain coefficient, and the steady-state output of the active power, specifically including: Determining the first pole of the active loop according to the active custom regulation time, the formula is: ； Among them, represents the active customized regulation time; Determining the second pole of the active loop according to the active gain coefficient, the steady-state output of the active power, and the first pole of the active loop, the formula is: ； Among them, A represents the active power gain coefficient, represents the steady-state output of active power when the system frequency changes by one hertz.

6. The control method of the virtual synchronous generator based on zero-pole configuration according to claim 1, characterized in that The formula for determining the integral coefficient of the reactive loop according to the reactive custom regulation time and the reactive gain coefficient is: ； Among them, represents the reactive power customized regulation time, B represents the reactive power gain coefficient, k iq represents the reactive power loop integral coefficient.

7. The control method of the virtual synchronous generator based on zero-pole configuration according to claim 1, characterized in that Generating the PWM signal of the converter according to the voltage control amount of the converter and the high-frequency triangular carrier signal, specifically including: Convert the voltage control quantity of the converter into the voltage control quantity in the coordinate system to obtain the three-phase control quantity; Comparing the three-phase control amount with the high-frequency triangular carrier signal; when the three-phase control amount is greater than the high-frequency triangular carrier signal, the converter switching device is turned on; when the three-phase control amount is less than the high-frequency triangular carrier signal, the converter switching device is turned off, generating the PWM signal of the converter.

8. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the control method of the virtual synchronous generator based on zero-pole configuration according to any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the control method of the virtual synchronous generator based on zero-pole configuration according to any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the control method of the virtual synchronous generator based on zero-pole configuration according to any one of claims 1-7.

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