A time difference fusion control method, system and device of a virtual synchronous generator

Abstract

The application discloses a time difference fusion control method, system and device of a virtual synchronous generator, relates to the technical field of virtual synchronous generators, and has the technical scheme as follows: a VSG control algorithm is used to calculate control parameters of VSG control; the control parameters at the current moment are decomposed into a first parameter participating in the VSG control at the current moment and a second parameter participating in the VSG control at the next moment; the first parameter participating in the VSG control at the current moment and the second parameter participating in the VSG control at the current moment and decomposed at the last moment are fused to obtain actual parameters of the VSG control at the current moment; the actual parameters of the VSG control at the current moment are input into double-loop control, and control signals for switching of the switch in the inverter are obtained after processing by an SPWM modulator. The application can effectively reduce the frequency and amplitude of primary frequency modulation and enhance the stability of distributed new energy grid connection while keeping the virtual inertia unchanged.

Description

Technical Field

[0001] This invention relates to the field of virtual synchronous generator technology, and more specifically, to a time difference fusion control method, system, and device for a virtual synchronous generator. Background Technology

[0002] As more and more distributed energy sources are connected to the power grid through power inverters, power inverters have the advantage of fast response speed, but they do not have the mechanical inertia and damping characteristics of traditional synchronous motors. They cannot provide inertia and damping for the system. Therefore, too many distributed energy sources connected to the power grid can easily cause the power system to lose stability.

[0003] A Virtual Synchronous Generator (VSG) embeds the mathematical model of a synchronous generator into the control algorithm of an inverter, simulating the operation of a rotating electrical machine using static power electronic devices. By simulating the primary frequency and voltage regulation of a synchronous generator, it enables functions such as damping rapid voltage and frequency fluctuations, automatic power distribution, and synchronous grid operation. In the entire VSG grid-connected system, the distributed renewable energy generation unit acts as a virtual prime mover, and the inverter acts as a virtual generator. During primary frequency regulation, the output power is generally compared with the power command of the VSG control, and the VSG control algorithm is used to calculate the control parameters (such as angle of attack and terminal voltage amplitude). These control parameters are then input into a dual-loop control system and processed by an SPWM (Sinusoidal PWM) modulator to obtain the control signals for controlling the on / off state of the switching transistors in the inverter, thereby adjusting the output power on the inverter's output side to adapt to load fluctuations.

[0004] However, when load fluctuations are large, the virtual inertia of the virtual synchronous generator needs to be sufficiently large. If the virtual inertia is insufficient to handle rapid power fluctuations, the power input of the virtual prime mover needs to be adjusted to achieve primary frequency regulation, and frequency restoration is performed after the system power is balanced. When the load fluctuates rapidly with large amplitudes, there is a problem of both the frequency and amplitude of primary frequency regulation being large, and the stability of distributed renewable energy grid connection needs further improvement. Therefore, how to research and design a time-difference fusion control method, system, and device for virtual synchronous generators that can overcome the above-mentioned defects is an urgent problem we need to solve. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a time-difference fusion control method, system, and device for virtual synchronous generators. When the load fluctuates rapidly with large amplitude, the parameters of two adjacent moments are superimposed and fused to cancel out adjacent fluctuations, resulting in smaller fluctuations in the actual parameters of VSG control. While keeping the virtual inertia constant, the frequency and amplitude of primary frequency regulation can be effectively reduced, thereby enhancing the stability of distributed renewable energy grid connection.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0007] Firstly, a time-difference fusion control method for a virtual synchronous generator is provided, comprising the following steps:

[0008] Collect the output power of the virtual synchronous generator during operation;

[0009] The output power is compared with the power command of VSG control, and the control parameters of VSG control are calculated using the VSG control algorithm.

[0010] The control parameters at the current moment are decomposed into a first parameter that participates in the VSG control at the current moment and a second parameter that participates in the VSG control at the next moment.

[0011] The first parameter involved in the VSG control at the current moment and the second parameter involved in the VSG control at the current moment, which was decomposed in the previous moment, are fused together to obtain the actual parameters of the VSG control at the current moment.

[0012] The actual parameters of the VSG control at the current moment are input into the dual-loop control, and after being processed by the SPWM modulator, the control signal for controlling the on and off of the switching transistors in the inverter is obtained.

[0013] Furthermore, the control parameters are the angle of attack and / or the terminal voltage amplitude.

[0014] Furthermore, after the control parameters are decomposed, the absolute value of the first parameter participating in the VSG control at the current moment is greater than the absolute value of the second parameter participating in the VSG control at the next moment.

[0015] Furthermore, the process of decomposing the control parameters at the current moment into a first parameter participating in the VSG control at the current moment and a second parameter participating in the VSG control at the next moment specifically involves:

[0016] The first parameter participating in the VSG control at the current moment is calculated by multiplying the control parameter at the current moment with the first decomposition coefficient;

[0017] The second parameter for the next VSG control is calculated by the difference between the control parameter at the current moment and the first parameter involved in the VSG control at the current moment.

[0018] The first decomposition coefficient is greater than 0.5 and less than 1.

[0019] Furthermore, the first decomposition coefficient is determined by the fluctuation range of the output power;

[0020] The greater the fluctuation range of the output power, the smaller the first decomposition coefficient.

[0021] Furthermore, the process of decomposing the control parameters at the current moment into a first parameter participating in the VSG control at the current moment and a second parameter participating in the VSG control at the next moment specifically involves:

[0022] The parameter variable is calculated by the difference between the control parameter at the current moment and the actual parameter at the previous moment;

[0023] The second parameter participating in the VSG control at the next moment is calculated by multiplying the parameter variable with the second decomposition coefficient;

[0024] The first parameter for VSG control at the current moment is calculated by the difference between the control parameter at the current moment and the second parameter for VSG control at the next moment;

[0025] The second decomposition coefficient is greater than 0 and less than 1.

[0026] Furthermore, the second decomposition coefficient is determined by the fluctuation range of the output power;

[0027] The greater the fluctuation range of the output power, the larger the second decomposition coefficient.

[0028] Furthermore, the specific formula for calculating the actual parameters is as follows:

[0029] B i =β i，1 +β i-1，2 ;

[0030] Among them, B i This represents the actual parameters of the VSG control at time i; β i，1 β represents the first parameter participating in the VSG control at time i after the control parameter decomposition at time i; i-1，2 This represents the second parameter that participates in the VSG control at time i after the control parameters at time i-1 are decomposed.

[0031] Secondly, a time-difference fusion control system for a virtual synchronous generator is provided, including:

[0032] The data acquisition module is used to collect the output power of the virtual synchronous generator during operation;

[0033] The initial control module is used to compare the output power with the power command of VSG control and to calculate the control parameters of VSG control using the VSG control algorithm;

[0034] The parameter decomposition module is used to decompose the control parameters at the current moment into a first parameter that participates in the VSG control at the current moment and a second parameter that participates in the VSG control at the next moment.

[0035] The parameter fusion module is used to fuse the first parameter involved in the current VSG control and the second parameter involved in the current VSG control decomposed from the previous time step to obtain the actual parameters of the current VSG control.

[0036] The signal modulation module is used to input the actual parameters of the VSG control at the current moment into the dual-loop control, and after processing by the SPWM modulator, obtain the control signal for controlling the on and off of the switching transistors in the inverter.

[0037] Thirdly, a VSG grid-connected device is provided, including a distributed photovoltaic power generation unit, an inverter, and at least one time-difference fusion control system for a virtual synchronous generator as described in the second aspect;

[0038] The distributed photovoltaic power generation unit is connected to the power grid system via an inverter;

[0039] The data acquisition module acquires the output power of the inverter output side;

[0040] The control signals generated by the time difference fusion control system of the virtual synchronous generator control the switching on and off of the switching transistors in the inverter.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The present invention provides a time-difference fusion control method for a virtual synchronous generator. The method uses the VSG control algorithm to calculate the control parameters of the VSG control and decompose them into two parts. One part is used for the VSG control at the current moment, and the other part is used for the VSG control at the next moment. When the load fluctuates rapidly with large amplitude, the parameters of two adjacent moments are superimposed and fused to cancel out adjacent fluctuations. This makes the actual parameter fluctuation of the VSG control smaller. While keeping the virtual inertia unchanged, the frequency and amplitude of primary frequency regulation can be effectively reduced, thereby enhancing the stability of distributed new energy grid connection.

[0043] 2. This invention has lower requirements for the virtual inertia of the system while keeping the frequency and amplitude of the first frequency modulation constant;

[0044] 3. This invention directly decomposes the control parameters at the current moment, which can enhance the response speed of time difference fusion control, while improving the effect of reducing the frequency and amplitude of primary frequency modulation.

[0045] 4. In order to reduce errors in the time difference fusion control process, this invention calculates the parameter variable by the difference between the control parameter at the current moment and the actual parameter at the previous moment, and then decomposes it based on the parameter variable, which can effectively ensure the accuracy of time difference fusion control. Attached Figure Description

[0046] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0047] Figure 1 This is a flowchart from Embodiment 1 of the present invention;

[0048] Figure 2 This is a system block diagram in Embodiment 2 of the present invention;

[0049] Figure 3 This is a schematic diagram of the working principle in Embodiment 3 of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0051] Example 1: A time-difference fusion control method for a virtual synchronous generator, such as... Figure 1 As shown, it includes the following steps:

[0052] S1: Collect the output power of the virtual synchronous generator during operation;

[0053] S2: Compare the output power with the power command of VSG control, and use the VSG control algorithm to calculate the control parameters of VSG control;

[0054] S3: Decompose the control parameters at the current moment into a first parameter that participates in the VSG control at the current moment and a second parameter that participates in the VSG control at the next moment;

[0055] S4: Combine the first parameter involved in the current VSG control with the second parameter involved in the current VSG control decomposed from the previous time step to obtain the actual parameters of the current VSG control.

[0056] S5: Input the actual parameters of the VSG control at the current moment into the dual-loop control, and after processing by the SPWM modulator, obtain the control signal for controlling the on and off of the switching transistors in the inverter.

[0057] In this embodiment, the control parameter can be the angle of attack, the terminal voltage amplitude, or both the angle of attack and the terminal voltage amplitude; there is no limitation on this.

[0058] It should be noted that, in order to ensure the reliability of the time difference fusion control process, after the control parameters are decomposed, the absolute value of the first parameter participating in the VSG control at the current moment is greater than the absolute value of the second parameter participating in the VSG control at the next moment.

[0059] As an optional implementation method, the process of decomposing the control parameters at the current moment into a first parameter participating in the VSG control at the current moment and a second parameter participating in the VSG control at the next moment is as follows: the first parameter participating in the VSG control at the current moment is calculated by the product of the control parameters at the current moment and the first decomposition coefficient; the second parameter participating in the VSG control at the next moment is calculated by the difference between the control parameters at the current moment and the first parameter participating in the VSG control at the current moment; wherein, the first decomposition coefficient is greater than 0.5 and less than 1.

[0060] It should be noted that the first decomposition coefficient can be flexibly adjusted as needed, such as by the fluctuation range of the output power; the greater the fluctuation range of the output power, the smaller the first decomposition coefficient.

[0061] Taking the terminal voltage amplitude as an example, the first decomposition coefficient is set to 0.8. If the VSG control algorithm is used to calculate the terminal voltage amplitude under VSG control in the previous time period as E... t-1 The current VSG-controlled terminal voltage amplitude is E. t Traditional technology directly converts E t-1 E t The input is fed into a dual-loop control system, which includes voltage outer loop control and current inner loop control.

[0062] The present invention will measure the terminal voltage amplitude E t-1 The decomposition process is as follows:

[0063]

[0064] Among them, E t-1,1 Indicates the amplitude of the terminal voltage E t-1 The first parameter obtained from the decomposition, and E t-1,2 Indicates the amplitude of the terminal voltage E t-1 The second parameter obtained from the decomposition.

[0065] Similarly, it can be concluded that the present invention will increase the terminal voltage amplitude E t The decomposition process is as follows:

[0066]

[0067] Among them, Et,1 Indicates the amplitude of the terminal voltage E t The first parameter obtained from the decomposition, and E t,2 Indicates the amplitude of the terminal voltage E t The second parameter obtained from the decomposition.

[0068] When performing time zone fusion control, it is necessary to adjust E t,1 and E t-1,2 The sum of these values ​​serves as the actual parameter E for VSG control at the current moment. t,all That is: E t,all =E t,1 +E t-1,2 =0.8E t +0.2E t-1 And regardless of the terminal voltage amplitude E t-1 Is it large, or is it the amplitude E of the terminal voltage controlled by the VSG at the current moment? t Larger, compared to the terminal voltage amplitude E t In terms of actual parameter E t,all Both will reduce the amplitude E of the terminal voltage. t-1 The difference between them allows for an effective reduction in the frequency and amplitude of primary frequency regulation while keeping the virtual inertia constant, thus enhancing the stability of distributed new energy grid connection.

[0069] As another optional implementation, the process of decomposing the control parameters at the current moment into a first parameter participating in the VSG control at the current moment and a second parameter participating in the VSG control at the next moment is as follows: the parameter variable is calculated by the difference between the control parameters at the current moment and the actual parameters at the previous moment; the second parameter participating in the VSG control at the next moment is calculated by the product of the parameter variable and the second decomposition coefficient; the first parameter participating in the VSG control at the current moment is calculated by the difference between the control parameters at the current moment and the second parameter participating in the VSG control at the next moment; wherein, the second decomposition coefficient takes a value greater than 0 and less than 1.

[0070] It should be noted that the second decomposition coefficient can be flexibly adjusted as needed, such as by the fluctuation range of the output power; the greater the fluctuation range of the output power, the larger the second decomposition coefficient.

[0071] In this embodiment, the formula for calculating the actual parameters is as follows:

[0072] B i =β i，1 +β i-1，2 ;

[0073] Among them, B i This represents the actual parameters of the VSG control at time i; β i，1β represents the first parameter participating in the VSG control at time i after the control parameter decomposition at time i; i-1，2 This represents the second parameter that participates in the VSG control at time i after the control parameters at time i-1 are decomposed.

[0074] Example 2: A time-difference fusion control system for a virtual synchronous generator, which implements the time-difference fusion control method for a virtual synchronous generator described in Example 1, such as... Figure 2 As shown, it includes a data acquisition module, an initial control module, a parameter decomposition module, a parameter fusion module, and a signal modulation module.

[0075] The system comprises the following modules: a data acquisition module for acquiring the output power of the virtual synchronous generator during operation; an initial control module for comparing the output power with the power command of the VSG control and calculating the control parameters of the VSG control using the VSG control algorithm; a parameter decomposition module for decomposing the control parameters at the current moment into a first parameter participating in the VSG control at the current moment and a second parameter participating in the VSG control at the next moment; a parameter fusion module for fusing the first parameter participating in the VSG control at the current moment with the second parameter decomposed from the previous moment to obtain the actual parameters of the VSG control at the current moment; and a signal modulation module for inputting the actual parameters of the VSG control at the current moment into the dual-loop control and processing them through an SPWM modulator to obtain the control signal for controlling the switching of the transistors in the inverter.

[0076] Example 3: A VSG grid-connected device, such as Figure 3 As shown, the system includes a distributed photovoltaic power generation unit, an inverter, and a time-difference fusion control system for a virtual synchronous generator as described in Example 2. The distributed photovoltaic power generation unit is connected to the power grid via the inverter; a data acquisition module acquires the output power from the inverter's output side; and the control signals generated by the time-difference fusion control system of the virtual synchronous generator control the switching on and off of the switching transistors in the inverter.

[0077] Working principle: This invention uses the VSG control algorithm to calculate the control parameters of VSG control, which are decomposed into two parts. One part is used for VSG control at the current moment, and the other part is used for VSG control at the next moment. When the load fluctuates rapidly with large amplitude, the parameters of two adjacent moments are superimposed and fused to cancel out adjacent fluctuations, resulting in smaller fluctuations in the actual parameters of VSG control. While keeping the virtual inertia unchanged, it can effectively reduce the frequency and amplitude of primary frequency regulation and enhance the stability of distributed new energy grid connection.

[0078] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0079] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0080] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0081] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0082] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A time-difference fusion control method for a virtual synchronous generator, characterized in that, Includes the following steps: Collect the output power of the virtual synchronous generator during operation; The output power is compared with the power command of VSG control, and the control parameters of VSG control are calculated using the VSG control algorithm. The control parameters at the current moment are decomposed into a first parameter that participates in the VSG control at the current moment and a second parameter that participates in the VSG control at the next moment. The first parameter involved in the VSG control at the current moment and the second parameter involved in the VSG control at the current moment, which was decomposed in the previous moment, are fused together to obtain the actual parameters of the VSG control at the current moment. The actual parameters of the VSG control at the current moment are input into the dual-loop control, and after being processed by the SPWM modulator, the control signal for controlling the on and off of the switching transistors in the inverter is obtained.

2. The time-difference fusion control method for a virtual synchronous generator according to claim 1, characterized in that, The control parameters are the power angle and / or the terminal voltage amplitude.

3. The time-difference fusion control method for a virtual synchronous generator according to claim 1, characterized in that, After the control parameters are decomposed, the absolute value of the first parameter participating in the VSG control at the current moment is greater than the absolute value of the second parameter participating in the VSG control at the next moment.

4. The time-difference fusion control method for a virtual synchronous generator according to claim 1, characterized in that, The process of decomposing the control parameters at the current moment into a first parameter participating in the VSG control at the current moment and a second parameter participating in the VSG control at the next moment is as follows: The first parameter participating in the VSG control at the current moment is calculated by multiplying the control parameter at the current moment with the first decomposition coefficient; The second parameter for the next VSG control is calculated by the difference between the control parameter at the current moment and the first parameter involved in the VSG control at the current moment. The first decomposition coefficient is greater than 0.5 and less than 1.

5. The time-difference fusion control method for a virtual synchronous generator according to claim 4, characterized in that, The first decomposition coefficient is determined by the fluctuation range of the output power; The greater the fluctuation range of the output power, the smaller the first decomposition coefficient.

6. The time-difference fusion control method for a virtual synchronous generator according to claim 1, characterized in that, The process of decomposing the control parameters at the current moment into a first parameter participating in the VSG control at the current moment and a second parameter participating in the VSG control at the next moment is as follows: The parameter variable is calculated by the difference between the control parameter at the current moment and the actual parameter at the previous moment; The second parameter participating in the VSG control at the next moment is calculated by multiplying the parameter variable with the second decomposition coefficient; The first parameter for VSG control at the current moment is calculated by the difference between the control parameter at the current moment and the second parameter for VSG control at the next moment; The second decomposition coefficient is greater than 0 and less than 1.

7. The time-difference fusion control method for a virtual synchronous generator according to claim 6, characterized in that, The second decomposition coefficient is determined by the fluctuation range of the output power; The greater the fluctuation range of the output power, the larger the second decomposition coefficient.

8. The time-difference fusion control method for a virtual synchronous generator according to claim 1, characterized in that, The specific formula for calculating the actual parameters is as follows: B i ＝β i，1 +β i-1，2 ； Among them, B i This represents the actual parameters of the VSG control at time i; β i，1 β represents the first parameter participating in the VSG control at time i after the control parameter decomposition at time i; i-1，2 This represents the second parameter that participates in the VSG control at time i after the control parameters at time i-1 are decomposed.

9. A time-difference fusion control system for a virtual synchronous generator, characterized in that, include: The data acquisition module is used to collect the output power of the virtual synchronous generator during operation; The initial control module is used to compare the output power with the power command of VSG control and to calculate the control parameters of VSG control using the VSG control algorithm; The parameter decomposition module is used to decompose the control parameters at the current moment into a first parameter that participates in the VSG control at the current moment and a second parameter that participates in the VSG control at the next moment. The parameter fusion module is used to fuse the first parameter involved in the current VSG control and the second parameter involved in the current VSG control decomposed from the previous time step to obtain the actual parameters of the current VSG control. The signal modulation module is used to input the actual parameters of the VSG control at the current moment into the dual-loop control, and after processing by the SPWM modulator, obtain the control signal for controlling the on and off of the switching transistors in the inverter.

10. A VSG grid-connected device, characterized in that, Includes a distributed photovoltaic power generation unit, an inverter, and at least one time-difference fusion control system for a virtual synchronous generator as described in claim 9; The distributed photovoltaic power generation unit is connected to the power grid system via an inverter; The data acquisition module acquires the output power of the inverter output side; The control signals generated by the time difference fusion control system of the virtual synchronous generator control the switching on and off of the switching transistors in the inverter.

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