Subsynchronous oscillation suppression method and system for virtual synchronous generator

Abstract

The invention discloses a subsynchronous oscillation suppression method and system for a virtual synchronous generator. The method comprises the following steps: acquiring a first parameter set of a target virtual synchronous generator; calculating a first reference angle and a first voltage amplitude according to the first parameter set; calculating a first current reference value according to the first voltage amplitude in combination with a preset voltage control strategy; and calculating a first duty ratio signal according to the first reference angle and the first current reference value in combination with the real-time output current of the target virtual synchronous generator, and performing sub-synchronous oscillation suppression of the virtual synchronous generator. An impedance remodeling control link is added in a current controller of the virtual synchronous generator, and the output impedance of the virtual synchronous generator is reconstructed so as to correct the phase angle characteristic of the virtual synchronous generator. The operation stability of the virtual synchronous generator grid-connected system can be improved, and the subsynchronous oscillation problem of the virtual synchronous generator grid-connected system can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of virtual synchronous machine control in renewable energy power generation, and in particular to a method and system for suppressing subsynchronous oscillation of a virtual synchronous generator. Background Art

[0002] New energy power generation, mainly wind power and photovoltaics, is increasingly used in engineering practice, which has greatly alleviated the energy crisis caused by the gradual depletion of traditional fossil energy. The use of new energy such as wind power and solar energy has the advantages of being clean and low-carbon.

[0003] Grid-connected inverters are important energy conversion equipment between renewable energy power generation and power grids and are often used in renewable energy grid-connected systems. However, with the large-scale access of power electronic equipment represented by grid-connected inverters, the power electronics of power systems have become increasingly prominent. Interaction oscillations between renewable energy power generation equipment and power grids are frequent, which may affect the stable operation of the grid-connected system and reduce the efficiency of power conversion. In severe cases, they may cause large-scale failures and generate huge economic losses.

[0004] In recent years, research on adding virtual synchronous generators to renewable energy grid-connected systems to improve the grid-connected stability of the system has attracted increasing attention. This is because virtual synchronous generators simulate the external characteristics of synchronous generators, do not need to rely on sampling the grid-connected point voltage to generate a reference phase angle, and have frequency and voltage regulation characteristics. However, renewable energy power generation has the characteristics of intermittency and volatility, which causes the grid strength to fluctuate within a wide range, which will cause the virtual synchronous generator grid-connected system to be in an unstable state. At present, the oscillation suppression methods for virtual synchronous generator grid-connected systems are mainly control parameter optimization and improved control methods. The control parameter optimization method usually designs a narrow parameter adjustment range that cannot meet the needs of engineering practice; and most of the existing improved control methods require cumbersome derivation processes, which are not conducive to promotion and application.

[0005] To solve the above problems, the present invention proposes an improved control method for improving the stability of the virtual synchronous generator grid-connected system when the power grid strength changes over a wide range, which is of great significance for improving the stability of new energy grid-connected operation and the level of new energy consumption. Summary of the invention

[0006] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0007] In view of the above existing problems, the present invention is proposed.

[0008] Therefore, the present invention provides a method and system for suppressing subsynchronous oscillation of a virtual synchronous generator, which can solve the problems mentioned in the background technology.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0010] In a first aspect, the present invention provides a method for suppressing subsynchronous oscillation of a virtual synchronous generator, comprising:

[0011] Acquire a first parameter set of a target virtual synchronous generator, wherein the first parameter set includes a first parameter, a second parameter, and a third parameter;

[0012] Calculate a first reference angle and a first voltage amplitude according to the first parameter set;

[0013] Calculating a first current reference value according to the first voltage amplitude and in combination with a preset voltage control strategy;

[0014] According to the first reference angle and the first current reference value, combined with the real-time output current of the target virtual synchronous generator, a first duty cycle signal is calculated to suppress the sub-synchronous oscillation of the virtual synchronous generator.

[0015] As a preferred solution of the method for suppressing subsynchronous oscillation of a virtual synchronous generator according to the present invention, the voltage control strategy includes:

[0016] The voltage control strategy is any strategy for solving the first current reference value by the first voltage amplitude;

[0017] The first voltage amplitude is obtained through the second parameter and the third parameter.

[0018] As a preferred solution of the method for suppressing subsynchronous oscillation of a virtual synchronous generator according to the present invention, the first duty cycle signal is calculated according to the first reference angle and the first current reference value in combination with the real-time output current of the target virtual synchronous generator, including:

[0019] Calculating a first difference between the first current reference value and the target virtual synchronous generator real-time output current;

[0020] Calculate a first duty cycle component using the first difference through a current control strategy;

[0021] A first duty cycle signal is calculated according to the first duty cycle component in combination with the first reference angle.

[0022] As a preferred solution of the method for suppressing subsynchronous oscillation of a virtual synchronous generator according to the present invention, the current control strategy includes:

[0023] The current control strategy is an arbitrary strategy for solving the first duty cycle component by the first difference;

[0024] The first difference is a difference between the first current reference value component and the target virtual synchronous generator real-time output current component.

[0025] As a preferred solution of the method for suppressing subsynchronous oscillation of a virtual synchronous generator according to the present invention, the calculating of the first reference angle according to the first parameter set comprises:

[0026] Calculating a first angular velocity according to a first parameter in the first parameter set;

[0027] An integration operation is performed on the first angular velocity to obtain a first reference angle.

[0028] As a preferred solution of the method for suppressing subsynchronous oscillation of a virtual synchronous generator according to the present invention, the first parameter set of the target virtual synchronous generator is obtained, and the first parameter set includes a first parameter, a second parameter and a third parameter, including:

[0029] The first parameter is the active power of the target virtual synchronous generator and its reference value;

[0030] The second parameter is the voltage amplitude and rated value at the grid connection point of the target virtual synchronous generator;

[0031] The third parameter is the reactive power at the target virtual synchronous generator grid connection point and its reference value.

[0032] As a preferred solution of the method for suppressing subsynchronous oscillation of a virtual synchronous generator according to the present invention, the step of calculating the first duty cycle signal according to the first duty cycle component in combination with the first reference angle comprises:

[0033] Performing a first coordinate system transformation on the first duty cycle component by using the first reference angle;

[0034] Recording the parameter after the transformation of the first coordinate system as a first duty cycle signal;

[0035] The first duty cycle signal includes three-phase duty cycle signals a, b, and c.

[0036] In a second aspect, the present invention provides a virtual synchronous generator subsynchronous oscillation suppression system, comprising:

[0037] A parameter acquisition module, used to acquire a first parameter set of a target virtual synchronous generator, wherein the first parameter set includes a first parameter, a second parameter and a third parameter;

[0038] A first calculation module, configured to calculate a first reference angle and a first voltage amplitude according to the first parameter set;

[0039] A second calculation module, configured to calculate a first current reference value according to the first voltage amplitude and in combination with a preset voltage control strategy;

[0040] The suppression module is used to calculate a first duty cycle signal according to the first reference angle and the first current reference value in combination with the real-time output current of the target virtual synchronous generator, so as to suppress the sub-synchronous oscillation of the virtual synchronous generator.

[0041] In a third aspect, the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned method when executing the computer program.

[0042] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the method described above when executed by a processor.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention proposes a method and system for suppressing subsynchronous oscillations of a virtual synchronous generator, obtaining a first parameter set of a target virtual synchronous generator, the first parameter set including a first parameter, a second parameter and a third parameter; calculating a first reference angle and a first voltage amplitude according to the first parameter set; calculating a first current reference value according to the first voltage amplitude in combination with a preset voltage control strategy; calculating a first duty cycle signal according to the first reference angle and the first current reference value in combination with the real-time output current of the target virtual synchronous generator, and suppressing subsynchronous oscillations of the virtual synchronous generator. By adding an impedance reshaping control link in the virtual synchronous generator current controller, the output impedance of the virtual synchronous generator is reconstructed to correct its phase angle characteristics. The present application can improve the operating stability of the virtual synchronous generator grid-connected system, and can be used to solve the subsynchronous oscillation problem of the virtual synchronous generator grid-connected system. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0045] Figure 1 A method flow chart of a method and system for suppressing subsynchronous oscillation of a virtual synchronous generator provided by an embodiment of the present invention;

[0046] Figure 2A main circuit topology and control structure diagram of a virtual synchronous generator subsynchronous oscillation suppression method and system after adopting an impedance reshaping control method provided by an embodiment of the present invention;

[0047] Figure 3 A d-axis voltage waveform diagram of the PCC point before and after the impedance reshaping control method is adopted in a virtual synchronous generator subsynchronous oscillation suppression method and system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0049] Example 1

[0050] Reference Figure 1-Figure 3 , which is the first embodiment of the present invention, provides a method and system for suppressing subsynchronous oscillation of a virtual synchronous generator, including:

[0051] There are some problems in the existing related technologies. For example, when the virtual synchronous generator grid-connected system faces a wide range of changes in grid strength, it is easy to have stability problems, resulting in sub-synchronous oscillation.

[0052] The present application provides a method that can effectively solve the above-mentioned problems. Next, how to implement the sub-synchronous oscillation suppression method of the virtual synchronous generator will be described in detail in combination with multiple embodiments;

[0053] Figure 1 A method flow chart of a virtual synchronous generator subsynchronous oscillation suppression method and system is shown, including:

[0054] S101, obtaining a first parameter set of a target virtual synchronous generator, where the first parameter set includes a first parameter, a second parameter, and a third parameter;

[0055] In an optional embodiment, the first parameter set of the target virtual synchronous generator is to achieve subsynchronous oscillation suppression for the virtual synchronous generator, so the specific parameters selected as the first parameter set are selected according to the actual operation process selected by relevant technical personnel;

[0056] In an optional embodiment, the first parameter set may select different parameters according to actual needs. For example, when subsynchronous oscillation suppression is performed by designing a detailed topological circuit structure, the active power of the target virtual synchronous generator and its reference value, the voltage amplitude at the target virtual synchronous generator grid connection point and its rated value, and the reactive power at the target virtual synchronous generator grid connection point and its reference value may be used as the first parameter set;

[0057] In an optional embodiment, when subsynchronous oscillation suppression is performed by designing a control strategy, the speed, torque and reference value of the target virtual synchronous generator, and the frequency and reference value of the target virtual synchronous generator may be used as the first parameter set.

[0058] In an embodiment of the present application, a first parameter set of a target virtual synchronous generator is obtained, and the first parameter set includes a first parameter, a second parameter, and a third parameter including:

[0059] The first parameter is the active power of the target virtual synchronous generator and its reference value;

[0060] The second parameter is the voltage amplitude and rated value at the grid connection point of the target virtual synchronous generator;

[0061] The third parameter is the reactive power at the target virtual synchronous generator grid connection point and its reference value.

[0062] In an optional embodiment, the active power of the target virtual synchronous generator and its reference value, the voltage amplitude and its rated value at the target virtual synchronous generator grid-connected point, and the reactive power and its reference value at the target virtual synchronous generator grid-connected point can be obtained by real-time measurement through measuring equipment, or the corresponding data can be obtained from the power grid management system through a communication interface.

[0063] In an optional embodiment, the measuring device may be a current transformer, a voltage transformer, etc., for real-time monitoring of the operating status of the target virtual synchronous generator. The communication interface may be a standard communication protocol interface, such as Modbus, IEC61850, etc., for data exchange with a power grid management system.

[0064] It should be noted that obtaining the first parameter set of the target virtual synchronous generator, the first parameter set including the first parameter, the second parameter and the third parameter can provide accurate operating parameters for the subsequent virtual synchronous generator control, thereby ensuring the correct implementation of the control strategy and the stability of the system. By real-time monitoring and obtaining these key parameters, the working state of the virtual synchronous generator can be adjusted in time to adapt to changes in the strength of the power grid and prevent the occurrence of subsynchronous oscillations. It can also provide necessary input data for the calculation and control in the following embodiments.

[0065] S102, calculating a first reference angle and a first voltage amplitude according to a first parameter set;

[0066] In an embodiment of the present application, calculating the first reference angle according to the first parameter set includes:

[0067] calculating a first angular velocity according to a first parameter in a first parameter set;

[0068] An integration operation is performed on the first angular velocity to obtain a first reference angle.

[0069] In an optional embodiment, the calculation of the first angular velocity according to the first parameter in the first parameter set can be calculated in different ways, for example, the angular velocity can be calculated using the active power of the target virtual synchronous generator and its reference value. The calculation of the angular velocity can be based on the mechanical characteristics of the generator, such as the moment of inertia and damping coefficient of the rotor, and the electromagnetic characteristics, such as the inductance and resistance of the stator and the rotor. Through these parameters, a dynamic model can be established to simulate the motion equation of the generator to obtain the angular velocity.

[0070] In an optional embodiment, a neural network model or a machine learning model may be established to calculate the first angular velocity according to the first parameter in the first parameter set. The neural network model or the machine learning model may be obtained by training with historical data to predict and calculate the angular velocity, thereby improving the accuracy and efficiency of the calculation.

[0071] In an optional embodiment, the relationship between the first parameter and the first angular velocity can be obtained by fitting the historical data, and the first angular velocity can be calculated by using the relationship. This method can use the statistical characteristics of historical data to provide a fast and relatively accurate way to calculate the angular velocity.

[0072] In an optional embodiment, after the first angular velocity is calculated, the first reference angle is obtained by an integration operation. The integration operation may be a numerical integration, such as a trapezoidal integration or a Simpson integration, or an analytical integration, depending on the real-time computing capability and accuracy requirements of the system.

[0073] In the embodiment of the present application, according to the active power P of the virtual synchronous generator s and its reference value P s *, get the first angular velocity ω of the virtual synchronous generator s (The first reference angle θ s Can be obtained by s Obtained through the integral link):

[0074]

[0075] Where, ω0 represents the fundamental frequency angular velocity; D prepresents the active damping coefficient; J represents the moment of inertia.

[0076] In an optional embodiment, the first voltage amplitude may be calculated in different ways, for example, by calculating the voltage amplitude and its rated value at the target virtual synchronous generator grid connection point and the reactive power and its reference value at the target virtual synchronous generator grid connection point;

[0077] In an optional embodiment, the first voltage amplitude can be calculated by establishing a mathematical model. The model can be based on the load characteristics of the power grid, the electrical parameters of the generator, and the voltage control requirements of the grid connection point. Through these parameters, the voltage response of the power grid can be simulated to obtain the first voltage amplitude.

[0078] In an optional embodiment, the mathematical model can be trained and predicted by a neural network model or a machine learning model. These models can use a large amount of historical data to learn the complex relationship between voltage amplitude and grid parameters, thereby providing an accurate prediction result.

[0079] In an optional embodiment, the historical data may be fitted to obtain a relational expression between the first parameter and the first voltage amplitude, and the first voltage amplitude may be calculated by using the relational expression. This method may utilize the statistical characteristics of the historical data to provide a fast and relatively accurate way to calculate the voltage amplitude.

[0080] In the embodiment of the present application, according to the PCC voltage amplitude U s and its rated value U s *, reactive power Q s and its reference value Q s *, the first voltage amplitude E of the virtual synchronous generator can be obtained s , and its calculation formula is:

[0081]

[0082] Among them, D q represents the reactive damping coefficient; K represents the excitation regulation coefficient.

[0083] It should be noted that calculating the first reference angle and the first voltage amplitude according to the first parameter set can provide an accurate reference benchmark for the control of the virtual synchronous generator, ensuring that the generator can maintain a stable operating state when the grid strength changes. The calculation of the first reference angle and the first voltage amplitude is a key step in achieving effective control, and they provide necessary input parameters for the subsequent current reference value calculation and duty cycle signal generation.

[0084] S103, calculating a first current reference value according to the first voltage amplitude and in combination with a preset voltage control strategy;

[0085] In the embodiment of the present application, the voltage control strategy includes:

[0086] The voltage control strategy is any strategy for solving the first current reference value by the first voltage amplitude;

[0087] The first voltage amplitude is obtained through the second parameter and the third parameter.

[0088] In an optional embodiment, the voltage control strategy can be implemented by different control algorithms, such as proportional-integral-derivative (PID) control, fuzzy control or adaptive control, etc. These control strategies can be dynamically adjusted according to the real-time state of the power grid and the operating parameters of the virtual synchronous generator to achieve the best voltage control effect.

[0089] In an optional embodiment, the voltage control strategy can be implemented by establishing a relationship model between the first voltage amplitude and the first current reference value, and the model can be designed based on the electrical characteristics of the virtual synchronous generator and the load characteristics of the power grid. In this way, it can be ensured that when the power grid voltage fluctuates, the virtual synchronous generator can output an appropriate current to maintain voltage stability.

[0090] In an optional embodiment, the method for establishing the relationship model can adopt a machine learning algorithm to obtain a prediction model through historical data training. The model can predict the optimal first current reference value according to the input first voltage amplitude, thereby realizing accurate control of the output current of the virtual synchronous generator.

[0091] In an optional embodiment, the method for establishing the relationship model may also determine the mathematical relationship between the first voltage amplitude and the first current reference value by fitting a function. For example, a polynomial fitting, exponential fitting, or logarithmic fitting method may be used to establish a mathematical expression based on the corresponding relationship between the first voltage amplitude and the first current reference value in the historical data, so that the first current reference value can be quickly and accurately calculated when the first voltage amplitude is given.

[0092] In the embodiment of the present application, the first voltage amplitude E s and the voltage d-axis component u d , voltage q-axis reference value 0 and voltage q-axis component u q The difference is respectively made and input into the voltage control loop. The voltage control loop is designed by the preset voltage control strategy and the dq components of the output current reference value are:

[0093]

[0094] Among them, k pu and k iu are the proportional coefficient and integral coefficient of the virtual synchronous generator voltage control loop, C fis the filter capacitance value of the virtual synchronous generator.

[0095] In an optional embodiment, an impedance reshaping controller may be designed according to actual needs. For example, the transfer function of the designed impedance reshaping controller Gir(s) is:

[0096]

[0097] Among them, λ1 and λ2 are impedance reshaping coefficients, ω z ,ω p Reshape the angular frequency for impedance, and λ1<λ2<1, ω p >ω z .

[0098] It should be noted that, according to the first voltage amplitude, combined with the preset voltage control strategy, calculating the first current reference value can ensure that the virtual synchronous generator can output an appropriate current to maintain voltage stability when the grid voltage fluctuates. By accurately controlling the output current, the subsynchronous oscillation phenomenon can be effectively suppressed and the stability of the entire grid-connected system can be improved. In addition, the design and implementation of the voltage control strategy need to consider the electrical characteristics of the virtual synchronous generator and the load characteristics of the grid to ensure the adaptability and effectiveness of the control strategy.

[0099] S104, calculating a first duty cycle signal according to the first reference angle and the first current reference value in combination with the real-time output current of the target virtual synchronous generator, and performing subsynchronous oscillation suppression of the virtual synchronous generator.

[0100] In the embodiment of the present application, according to the first reference angle and the first current reference value, combined with the real-time output current of the target virtual synchronous generator, calculating the first duty cycle signal includes:

[0101] Calculating a first difference between a first current reference value and a target virtual synchronous generator real-time output current;

[0102] Calculate a first duty cycle component using the first difference through a current control strategy;

[0103] A first duty cycle signal is calculated based on the first duty cycle component in combination with a first reference angle.

[0104] In the embodiment of the present application, the current control strategy includes:

[0105] The current control strategy is an arbitrary strategy for solving the first duty cycle component by the first difference;

[0106] The first difference is the difference between the first current reference value component and the target virtual synchronous generator real-time output current component.

[0107] In an optional embodiment, the current control strategy may adopt different control algorithms, such as proportional-integral (PI) control, proportional-integral-derivative (PID) control or fuzzy control, etc. These control strategies may be dynamically adjusted according to the real-time grid status and the operating parameters of the virtual synchronous generator to achieve precise control of the current.

[0108] In an optional embodiment, the current control strategy can be implemented by establishing a relationship model between the first difference and the first duty cycle component, and the model can be designed based on the electrical characteristics of the virtual synchronous generator and the load characteristics of the power grid. In this way, it can be ensured that when the power grid current fluctuates, the virtual synchronous generator can output an appropriate duty cycle signal to maintain current stability.

[0109] In an optional embodiment, the method for establishing the relationship model can adopt a machine learning algorithm to obtain a prediction model through historical data training. The model can predict the optimal first duty cycle component according to the input first difference, thereby realizing accurate control of the virtual synchronous generator output duty cycle signal.

[0110] In an optional embodiment, the method for establishing the relationship model may also determine the mathematical relationship between the first difference and the first duty cycle component by fitting a function. For example, a polynomial fitting, exponential fitting, or logarithmic fitting method may be used to establish a mathematical expression based on the corresponding relationship between the first difference and the first duty cycle component in the historical data, so that the first duty cycle component can be quickly and accurately calculated when the first difference is given.

[0111] In an embodiment of the present application, calculating the first duty cycle signal according to the first duty cycle component combined with the first reference angle includes:

[0112] Performing a first coordinate system transformation on the first duty cycle component by using a first reference angle;

[0113] Recording the parameter after the transformation of the first coordinate system as a first duty cycle signal;

[0114] The first duty cycle signal includes three-phase duty cycle signals a, b, and c.

[0115] In the embodiment of the present application, the d-axis component i of the output current of the virtual synchronous generator is d and the q-axis component i q With its reference value i d * and i q * Make the difference respectively, input the current control loop, and output the dq component of the virtual synchronous generator duty cycle d , d q ; through θ s Perform an inverse Park transform on the duty cycle dq component to obtain the three-phase duty cycle signal da , d b , d c , used to control the on and off of the virtual synchronous generator switch tube.

[0116] In summary, the present invention proposes a method for suppressing subsynchronous oscillations of a virtual synchronous generator, obtaining a first parameter set of a target virtual synchronous generator, wherein the first parameter set includes a first parameter, a second parameter, and a third parameter; calculating a first reference angle and a first voltage amplitude according to the first parameter set; calculating a first current reference value according to the first voltage amplitude in combination with a preset voltage control strategy; calculating a first duty cycle signal according to the first reference angle and the first current reference value in combination with the real-time output current of the target virtual synchronous generator, and suppressing subsynchronous oscillations of the virtual synchronous generator. By adding an impedance reshaping control link in the virtual synchronous generator current controller, the output impedance of the virtual synchronous generator is reconstructed to correct its phase angle characteristics. The present application can improve the operating stability of the virtual synchronous generator grid-connected system, and can be used to solve the subsynchronous oscillation problem of the virtual synchronous generator grid-connected system.

[0117] Example 2

[0118] This embodiment also provides a virtual synchronous generator subsynchronous oscillation suppression system, including:

[0119] A parameter acquisition module, used to acquire a first parameter set of a target virtual synchronous generator, the first parameter set including a first parameter, a second parameter and a third parameter;

[0120] A first calculation module, configured to calculate a first reference angle and a first voltage amplitude according to a first parameter set;

[0121] A second calculation module, used to calculate a first current reference value according to the first voltage amplitude in combination with a preset voltage control strategy;

[0122] The suppression module is used to calculate a first duty cycle signal according to a first reference angle and a first current reference value in combination with a real-time output current of a target virtual synchronous generator, so as to suppress subsynchronous oscillation of the virtual synchronous generator.

[0123] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0124] This embodiment also provides a computer device, which can be a terminal. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. 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 and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for suppressing subsynchronous oscillation of a virtual synchronous generator is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the housing of the computer device, or an external keyboard, touchpad or mouse.

[0125] This embodiment further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0126] Acquire a first parameter set of a target virtual synchronous generator, the first parameter set comprising a first parameter, a second parameter and a third parameter;

[0127] Calculate a first reference angle and a first voltage amplitude according to a first parameter set;

[0128] Calculating a first current reference value according to the first voltage amplitude and in combination with a preset voltage control strategy;

[0129] According to the first reference angle and the first current reference value, combined with the real-time output current of the target virtual synchronous generator, a first duty cycle signal is calculated to suppress the subsynchronous oscillation of the virtual synchronous generator.

[0130] Example 3

[0131] Reference Figure 2-Figure 3 , which is an embodiment of the present invention, provides a method and system for suppressing subsynchronous oscillation of a virtual synchronous generator. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0132] like Figure 2 As shown, the embodiment of the present invention provides a virtual synchronous generator grid-connected system and an impedance reshaping control method, which achieves the purpose of improving the stability of the grid-connected system by adding an impedance reshaping controller to the current controller of the virtual synchronous generator. The DC side voltage is V dc , e a 、eb 、e c Represents the output port voltage; i a 、i b 、i c Represents the output port current, whose dq component is i d 、i q , whose reference values ​​are i d * and i q *;u a 、u b 、u c represents the voltage at the PCC point, whose dq component is u d 、u q .L f , R f Represent the filter inductance and parasitic resistance respectively. s Indicates the active loop output reference angle, E s Indicates the output voltage amplitude of the reactive loop, d a d b d c Represents the duty cycle signal; R g Indicates the equivalent resistance of the power grid, L g Indicates the equivalent inductance of the power grid, U g Indicates the grid voltage.

[0133] The active power control loop output reference angle θ of the virtual synchronous generator s , reactive power control loop output voltage amplitude E s ; The d-axis voltage u of the virtual synchronous generator d and its reference value E s , q-axis voltage u d The difference between the reference value 0 and the reference value 0 is input into the voltage control loop to obtain the dq components i of the current reference value. d * and i q *, change i d and i d *、i q and i q * Make the difference respectively, and superimpose the voltage decoupling components respectively, and then input them into the current control loop, and superimpose the current decoupling components on the output dq components of the current control loop respectively, and output the dq components of the duty cycle; through θ s Perform an inverse Park transform on the dq component of the virtual synchronous generator duty cycle signal to output the virtual synchronous generator duty cycle signal d a d b d c , used to control the on and off of the virtual synchronous generator switch tube.

[0134] Figure 3This is a waveform comparison diagram of the d-axis component of the PCC point voltage in the virtual synchronous generator grid-connected system. Before adding the impedance reshaping controller, the d-axis voltage oscillates; after adding the impedance reshaping controller, the d-axis voltage tends to be stable after a short oscillation.

[0135] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0136] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0137] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0138] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0139] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0140] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0141] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for suppressing subsynchronous oscillation of a virtual synchronous generator, characterized in that: include: Acquire a first parameter set of a target virtual synchronous generator, wherein the first parameter set includes a first parameter, a second parameter, and a third parameter; Calculate a first reference angle and a first voltage amplitude according to the first parameter set; Calculating a first current reference value according to the first voltage amplitude and in combination with a preset voltage control strategy; According to the first reference angle and the first current reference value, combined with the real-time output current of the target virtual synchronous generator, a first duty cycle signal is calculated to suppress the sub-synchronous oscillation of the virtual synchronous generator.

2. The method for suppressing subsynchronous oscillation of a virtual synchronous generator according to claim 1, characterized in that: The voltage control strategy includes: The voltage control strategy is any strategy for solving the first current reference value by the first voltage amplitude; The first voltage amplitude is obtained through the second parameter and the third parameter.

3. The method for suppressing subsynchronous oscillation of a virtual synchronous generator according to claim 2, characterized in that: The calculating of the first duty cycle signal according to the first reference angle and the first current reference value in combination with the real-time output current of the target virtual synchronous generator includes: Calculating a first difference between the first current reference value and the target virtual synchronous generator real-time output current; Calculate a first duty cycle component using the first difference through a current control strategy; A first duty cycle signal is calculated according to the first duty cycle component in combination with the first reference angle.

4. The method for suppressing subsynchronous oscillation of a virtual synchronous generator according to claim 3, characterized in that: The current control strategy includes: The current control strategy is an arbitrary strategy for solving the first duty cycle component by the first difference; The first difference is a difference between the first current reference value component and the target virtual synchronous generator real-time output current component.

5. The method for suppressing subsynchronous oscillation of a virtual synchronous generator according to claim 4, characterized in that: Calculating the first reference angle according to the first parameter set comprises: Calculating a first angular velocity according to a first parameter in the first parameter set; An integration operation is performed on the first angular velocity to obtain a first reference angle.

6. The method for suppressing subsynchronous oscillation of a virtual synchronous generator according to claim 5, characterized in that: The first parameter set of the target virtual synchronous generator is obtained, wherein the first parameter set includes a first parameter, a second parameter and a third parameter, and includes: The first parameter is the active power of the target virtual synchronous generator and its reference value; The second parameter is the voltage amplitude and rated value at the grid connection point of the target virtual synchronous generator; The third parameter is the reactive power at the target virtual synchronous generator grid connection point and its reference value.

7. The method for suppressing subsynchronous oscillation of a virtual synchronous generator according to claim 6, characterized in that: Calculating a first duty cycle signal according to the first duty cycle component in combination with the first reference angle comprises: Performing a first coordinate system transformation on the first duty cycle component by using the first reference angle; Recording the parameter after the transformation of the first coordinate system as a first duty cycle signal; The first duty cycle signal includes three-phase duty cycle signals a, b, and c.

8. A virtual synchronous generator subsynchronous oscillation suppression system, characterized in that: include: A parameter acquisition module, used to acquire a first parameter set of a target virtual synchronous generator, wherein the first parameter set includes a first parameter, a second parameter and a third parameter; A first calculation module, configured to calculate a first reference angle and a first voltage amplitude according to the first parameter set; A second calculation module, configured to calculate a first current reference value according to the first voltage amplitude and in combination with a preset voltage control strategy; The suppression module is used to calculate a first duty cycle signal according to the first reference angle and the first current reference value in combination with the real-time output current of the target virtual synchronous generator, so as to suppress the sub-synchronous oscillation of the virtual synchronous generator.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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