Network construction amplitude locking control method, device and system and medium

Abstract

The invention provides a network construction amplitude locking control method, device and system and a medium, and the method comprises the steps: configuring an amplitude locking ring detection unit based on a unit negative feedback structure, and calculating a vector error signal of a terminal voltage d-axis component through an amplitude locking ring; and respectively inputting the d-axis voltage vector error signal and the q-axis component of the terminal voltage into two independent first-order filters for processing to generate corresponding filtering current signals. And the two filtering current signals jointly form a damping compensation current signal. And then the damping compensation current signal is injected into a current reference value of the grid-forming converter to enhance the response capability of the unstable dynamic phenomenon at the terminal voltage of the grid-forming converter, so that the system stability is improved. According to the invention, the instability phenomenon is inhibited by detecting the dynamic characteristics of the terminal voltage and generating the compensation signal. The dynamic characteristics of the PCC voltage need to be reflected on d-axis and q-axis components at the same time, and network-building amplitude-locking control cooperatively considers the dynamic response of a voltage vector in two axial directions, so that two-dimensional damping is realized. According to the method, the system stability is enhanced by injecting the additional compensation signal into the current control ring, and the network-forming converter does not need to be fundamentally modified.

Description

Technical Field

[0001] This invention relates to the field of DC power grid stability and control, specifically to a grid-connected converter grid-locking control method, device, system, and medium. Background Technology

[0002] With the acceleration of my country's energy transition, the proportion of low-carbon and clean energy use continues to rise. The integration of new energy sources such as wind and solar power has presented unprecedented challenges to the power grid, especially in some weak-end grid areas. These areas have high grid loads, low inertia, and generally rely on external power sources. The volatility and instability of new energy sources pose a serious threat to the safety and stability of the power grid. According to statistics from the National Energy Administration, in 2022, subsynchronous / supersynchronous oscillation events caused by new energy power plants increased by 37% year-on-year, seriously threatening the safe operation of the power grid. Against this backdrop, grid-based energy storage technology, with its unique voltage source characteristics and self-supporting inertia capabilities, has become a key breakthrough in solving the stability dilemma of "high-voltage and high-inertia" systems.

[0003] Grid-based converters possess unique capabilities in adjusting inertia and damping, effectively enhancing the grid's response to frequency fluctuations and suppressing small-scale disturbances caused by renewable energy fluctuations. Particularly in weak-end grids, grid-based energy storage plays a crucial role, providing necessary frequency and voltage support and improving the system's disturbance immunity. While demonstrating key capabilities in wind power, energy storage, and hybrid power supply scenarios, large-scale engineering still faces challenges. For example, the Dersalloch wind farm in Scotland, the Hornsdale energy storage project in South Australia, and grid-based energy storage power stations in Jingmen, Hubei and Laiwu, Shandong, China, demonstrate that research on the application of grid-based converters in weak-end grids, especially in terms of stability support, oscillation suppression, and control optimization, has significant practical implications. Summary of the Invention

[0004] The proposed grid-locked amplitude controller falls under the category of active damping methods for small-signal stability. This method suppresses instability by detecting the dynamic characteristics of the terminal voltage and generating a compensation signal. The dynamic characteristics of the PCC voltage need to be reflected in both the d-axis and q-axis components. The grid-locked amplitude control collaboratively considers the dynamic response of the voltage vector in both axes to achieve two-dimensional damping.

[0005] A method for controlling the width of a screen includes the following steps:

[0006] Step S1: Configure a locking loop detection unit based on a unity negative feedback structure, and calculate the voltage amplitude error signal of the terminal voltage d-axis component in the rotating coordinate system through the locking loop detection unit;

[0007] Step S2: Input the voltage amplitude error signal and the terminal voltage component in the q-axis of the rotating coordinate system into two independent first-order filters for processing to generate two corresponding filtered current signals. The two filtered current signals together constitute the damping compensation current signal.

[0008] Step S3 injects the damping compensation current signal into the current reference value of the grid-type converter to enhance the response capability of the grid-type converter to dynamic phenomena of unstable terminal voltage, thereby improving system stability.

[0009] Furthermore, in step S1, the voltage amplitude error signal of the terminal voltage in the d-axis component of the rotating coordinate system is calculated by the amplitude-locking loop detection unit, including:

[0010] The synchronization phase angle of the power grid is obtained through virtual synchronization control, and the three-phase instantaneous terminal voltage V is used to... ta V tb V tc Perform a dq rotation coordinate transformation to obtain the corresponding d-axis voltage component V. td and q-axis voltage component V tq :

[0011] (1);

[0012] (2);

[0013] Where T abc / dq This is the rotation coordinate transformation matrix;

[0014] The amplitude-locking loop in the amplitude-locking loop detection unit is implemented using a unity negative feedback structure. Its forward channel consists of an integrator with a transfer function of 1 / s and a gain coefficient of 1 / k. ca Composed of series connection;

[0015] The d-axis voltage component V td Input to the amplitude-locked loop, and output the estimated value V of the voltage amplitude. m ;

[0016] Calculate the d-axis voltage component V td Compared with the estimated value V m The difference between them is used to obtain the voltage amplitude error signal V. e :

[0017] (3);

[0018] (4);

[0019] Furthermore, step S2 includes:

[0020] The voltage amplitude error signal V obtained from the amplitude-locking loop in step S2 e Input first-order filter K q (s), outputting the damping compensation current signal injected into the q-axis:

[0021] (5);

[0022] The q-axis component V of the terminal voltage tq Input to the second first-order filter K d (s), outputting the damping compensation current signal injected into the d-axis:

[0023] (6);

[0024] Among them, the first-order filter K q (s) and the second first-order filter K d The transfer functions of (s) are as follows:

[0025] (7);

[0026] (8);

[0027] Where k q and k d The scaling factor, T, of a first-order filter q and T d is the time constant of the first-order filter.

[0028] Furthermore, step S3 injects the damping compensation current signal into the current reference value of the grid-type converter to enhance the response capability of the grid-type converter to dynamic phenomena of unstable terminal voltage, thereby improving system stability. Specifically, this includes:

[0029] The grid-type converter generates initial reference current signals i*d and i*q through a voltage control loop;

[0030] (9);

[0031] (10);

[0032] The damping compensation current signal , The new reference current signals are obtained by injecting them into the initial reference current signals respectively.

[0033] The new reference current signal is input into the current control loop to obtain the reference internal potential signal, which is then input into the PWM generator after Parker inverse transformation to generate the trigger signal for the power device.

[0034] The new reference current is:

[0035] (11);

[0036] (12);

[0037] The reference internal electromotive force signal is:

[0038] (13);

[0039] (14);

[0040] Where k p1 k p2 , where k is the proportional gain of the voltage control loop. i1 k i2 k represents the integral coefficient of the voltage control loop. p3 k p4 , where k is the proportional coefficient of the current control loop. i4 k i4 is the integral coefficient of the current control loop.

[0041] A net width locking control device, comprising:

[0042] The amplitude-locking loop module is used to detect the amplitude of the terminal voltage and calculate the voltage amplitude error signal of the d-axis component of the terminal voltage in the rotating coordinate system.

[0043] The filter module, connected to the amplitude-locking loop module, is used to input the voltage amplitude error signal and the q-axis component of the terminal voltage in the rotating coordinate system into two independent first-order filters for processing, generating two corresponding filtered current signals. The two filtered current signals together constitute the damping compensation current signal.

[0044] The grid-type amplitude locking control module, connected to the filter module, is used to inject the damping compensation current signal into the current reference value of the grid-type converter to enhance system stability.

[0045] Furthermore, the amplitude-locking loop module is implemented using a unity negative feedback structure, and its forward channel consists of an integrator with a transfer function of 1 / s and a gain coefficient of 1 / k. ca Composed of series connection;

[0046] The input terminal of the amplitude-locked loop module receives the d-axis voltage component V after dq transformation. td The estimated value of the output voltage amplitude V m And by comparing V td Compared with the estimated value V m The difference between them is used to obtain the voltage amplitude error signal V. e .

[0047] Furthermore, the filter module includes:

[0048] The first-order filter is used to filter the voltage amplitude error signal V. e Filtering is performed to output the q-axis damping compensation current signal. ;

[0049] The second first-order filter is used to filter the q-axis voltage component V. tq Filtering is performed to output the d-axis damping compensation current signal. .

[0050] Furthermore, the mesh-locking control module includes:

[0051] The current reference correction unit is used to convert the damping compensation current signal , A new reference current signal is obtained by injecting it into the initial reference current signal output by the voltage control loop;

[0052] A current control unit is used to generate a reference internal potential signal based on the new reference current signal;

[0053] The coordinate transformation unit is used to convert the reference internal potential signal into a modulation signal in a three-phase stationary coordinate system and input it into the PWM generator.

[0054] A net-locking control system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the net-locking control method described above.

[0055] A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the meshing and width-locking control method described above.

[0056] This invention enhances system stability by injecting an additional compensation signal into the current control loop without requiring fundamental modifications to the grid-type converter. This compensation signal is zero during steady-state operation, thus not affecting the system operating point, but during dynamic processes, it accurately tracks voltage dynamics and rapidly completes adjustments. Attached Figure Description

[0057] Figure 1 This is the control block diagram of the flap lock loop;

[0058] Figure 2 This is a topology diagram of a grid-type converter with grid-locked amplitude control;

[0059] Figure 3 These are waveforms of active power when a traditional grid-type converter and a grid-type converter with added grid-type amplitude locking control are subjected to disturbances.

[0060] Figure 4 This is a flowchart of a web-locking width control method according to an embodiment of the present invention. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0062] like Figure 4 As shown, an embodiment of the present invention provides a method for controlling the width of a wire mesh, comprising the following steps:

[0063] Step (1): Configure a amplitude-locked loop detection unit based on a unity negative feedback structure. The vector error signal of the d-axis component of the terminal voltage is calculated using the amplitude-locked loop. The amplitude-locked loop is implemented using a unity negative feedback structure. Its forward channel consists of an integrator (transfer function 1 / s) and a gain coefficient 1 / k. ca It is connected in series.

[0064] After obtaining the synchronization phase angle of the power grid through virtual synchronization control, the three-phase instantaneous terminal voltages are transformed using this phase angle to obtain the corresponding d-axis voltage components V. td and q-axis voltage component V tq .

[0065] (1)

[0066] (2)

[0067] The amplitude-locked loop (MLL) is implemented using a unity negative feedback structure. Its forward path consists of an integrator (transfer function 1 / s) and a gain coefficient 1 / k. ca Series configuration (e.g.) Figure 1 (As shown). The core working principle of the amplitude-locking loop is to transform the terminal voltage into V after dq transformation. td The component is taken as the input signal, and the output signal after passing through the amplitude-locked loop module is regarded as the estimated value V of the terminal voltage amplitude. m By calculating the input signal V td With output signal V m The difference between them forms the voltage amplitude error signal V. e Voltage amplitude error signal V e Represented as:

[0068] (3)

[0069] (4)

[0070] The error signal V e After passing through the forward passage (1 / s*k) ca After processing, the output is the locked terminal voltage amplitude V. m Its closed-loop control objective is the steady-state error V. e The voltage approaches zero, thus achieving the voltage amplitude V at the opposite end. m Precise tracking and locking.

[0071] Step (2): The d-axis voltage error signal and the q-axis component of the terminal voltage in the rotating coordinate system are respectively input into two independent first-order low-pass filters for processing, generating corresponding filtered compensation current signals. These two filtered current signals are superimposed and combined to form the damping compensation current signal:

[0072] The d-axis voltage error signal V obtained by the amplitude locking loop in step (1) e Input a first-order filter K q (s), whose output is the damping compensation current signal injected into the q-axis:

[0073] (5)

[0074] The q-axis component V of the terminal voltage tq Input another first-order filter K d (s), whose output is the damping compensation current signal injected into the d-axis:

[0075] (6)

[0076] The transfer functions of the first-order filters used for generating q-axis and d-axis compensation currents are as follows:

[0077] (7)

[0078] (8)

[0079] Where k q and k d The scaling factor, T, of a first-order filter q and T d is the time constant of the first-order filter.

[0080] Step (3): As Figure 2 The generated filtered current signal is injected into the current reference value of the grid converter, causing the current loop to adjust according to the new reference value: The grid converter's sensing terminal voltage V... tAnd the output current i0, V is obtained by using the Park transform. t-dq i 0-dq After decoupling, the voltage and current are used for power calculation to obtain the active and reactive power values ​​in real time. Then, the active power P, reactive power Q, and corresponding reference values ​​are input to the power outer loop control. By simulating the synchronous machine rotor and excitation equations, the reference phase and reference voltage V are output. t * .

[0081] Furthermore, the reference voltage serves as the input value for the d-axis voltage control loop reference value, while the input value for the q-axis reference value is 0. The voltage control loop then generates the initial reference current signals i*d and i*q.

[0082] (9)

[0083] (10)

[0084] The grid-locked amplitude control injects the damping compensation signal obtained in step (2) into the reference current to obtain a new reference current:

[0085] (11)

[0086] (12)

[0087] Then, a reference internal potential signal is obtained through current loop control:

[0088] (13)

[0089] (14)

[0090] Finally, the internal potential in the three-phase coordinate system is obtained through the Park inverse transformation, and it is used as the modulation signal input to the PWM generator to generate the trigger signal for the power device.

[0091] Where k p1 k p2 , where k is the proportional gain of the voltage control loop. i1 k i2 k represents the integral coefficient of the voltage control loop. p3 k p4 , where k is the proportional coefficient of the current control loop. i4 k i4 is the integral coefficient of the current control loop.

[0092] Grid-locked amplitude control suppresses instability by analyzing the dynamic characteristics of the terminal voltage and generating a compensation signal. The dynamic characteristics of the PCC voltage must be reflected in both the d-axis and q-axis components. Grid-locked amplitude control considers the dynamic response of the voltage vector in both axes to achieve two-dimensional damping, avoiding fundamental modifications to the grid-type converter. During steady-state operation, the compensation signal is zero, not changing the system operating point, and it can accurately track the reference value during dynamic processes. Figure 3 As shown, under the same parameter conditions, comparing the active power waveforms of a traditional grid-type converter and a grid-type converter with grid-type amplitude locking control under disturbances, it can be seen that grid-type amplitude locking control effectively suppresses active power oscillations and improves system stability.

[0093] This invention also provides a net-setting width-locking control device, comprising:

[0094] The amplitude-locking loop module is used to detect the amplitude of the terminal voltage and calculate the voltage amplitude error signal of the d-axis component of the terminal voltage in the rotating coordinate system.

[0095] The filter module, connected to the amplitude-locking loop module, is used to input the voltage amplitude error signal and the q-axis component of the terminal voltage in the rotating coordinate system into two independent first-order filters for processing, generating two corresponding filtered current signals. The two filtered current signals together constitute the damping compensation current signal.

[0096] The grid-type amplitude locking control module, connected to the filter module, is used to inject the damping compensation current signal into the current reference value of the grid-type converter to enhance system stability.

[0097] Another embodiment of the present invention provides a net-locking control system, comprising: a computer-readable storage medium and a processor;

[0098] The computer-readable storage medium is used to store executable instructions;

[0099] The processor is used to read executable instructions stored in the computer-readable storage medium and execute the meshing and width-locking control method described in the first aspect.

[0100] Another embodiment of the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the meshing and width-locking control method described in the first aspect.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling the width of a mesh, characterized in that, Includes the following steps: Step S1: Configure a locking loop detection unit based on a unity negative feedback structure, and calculate the voltage amplitude error signal of the terminal voltage d-axis component in the rotating coordinate system through the locking loop detection unit; Step S2: Input the voltage amplitude error signal and the terminal voltage component in the q-axis of the rotating coordinate system into two independent first-order filters for processing to generate two corresponding filtered current signals. The two filtered current signals together constitute the damping compensation current signal. Step S3 injects the damping compensation current signal into the current reference value of the grid-type converter to enhance the response capability of the grid-type converter to dynamic phenomena of unstable terminal voltage, thereby improving system stability.

2. The mesh width locking control method as described in claim 1, characterized in that: Step S1, which involves calculating the voltage amplitude error signal of the terminal voltage d-axis component in the rotating coordinate system using the amplitude-locking loop detection unit, includes: The synchronization phase angle of the power grid is obtained through virtual synchronization control, and the three-phase instantaneous terminal voltage V is used to... ta V tb V tc Perform a dq rotation coordinate transformation to obtain the corresponding d-axis voltage component V. td and q-axis voltage component V tq : （1）； （2）； Where T abc / dq This is the rotation coordinate transformation matrix; The amplitude-locking loop in the amplitude-locking loop detection unit is implemented using a unity negative feedback structure. Its forward channel consists of an integrator with a transfer function of 1 / s and a gain coefficient of 1 / k. ca Composed of series connection; The d-axis voltage component V td Input to the amplitude-locked loop, and output the estimated value V of the voltage amplitude. m ; Calculate the d-axis voltage component V td Compared with the estimated value V m The difference between them is used to obtain the voltage amplitude error signal V. e : （3）； （4）。 3. The mesh width locking control method as described in claim 1, characterized in that: Step S2 includes: The voltage amplitude error signal V obtained from the amplitude-locking loop in step S2 e Input first-order filter K q (s), outputting the damping compensation current signal injected into the q-axis: （5）； The q-axis component V of the terminal voltage tq Input to the second first-order filter K d (s), outputting the damping compensation current signal injected into the d-axis: （6）； Among them, the first-order filter K q (s) and the second first-order filter K d The transfer functions of (s) are as follows: （7）； （8）； Where k q and k d The scaling factor, T, of a first-order filter q and T d is the time constant of the first-order filter.

4. The mesh-locking width control method as described in claim 1, characterized in that: Step S3 involves injecting the damping compensation current signal into the current reference value of the grid-type converter to enhance the response capability of the grid-type converter to dynamic phenomena of unstable terminal voltage, thereby improving system stability. Specifically, this includes: The grid-type converter generates initial reference current signals i*d and i*q through a voltage control loop; （9）； （10）； The damping compensation current signal , The new reference current signals are obtained by injecting them into the initial reference current signals respectively. The new reference current signal is input into the current control loop to obtain the reference internal potential signal, which is then input into the PWM generator after Parker inverse transformation to generate the trigger signal for the power device. The new reference current is: （11）； （12）； The reference internal electromotive force signal is: （13）； （14）； Where k p1 k p2 , where k is the proportional gain of the voltage control loop. i1 k i2 k represents the integral coefficient of the voltage control loop. p3 k p4 , where k is the proportional coefficient of the current control loop. i4 k i4 is the integral coefficient of the current control loop.

5. A net-setting width-locking control device, characterized in that, include: The amplitude-locking loop module is used to detect the amplitude of the terminal voltage and calculate the voltage amplitude error signal of the d-axis component of the terminal voltage in the rotating coordinate system. The filter module, connected to the amplitude-locking loop module, is used to input the voltage amplitude error signal and the q-axis component of the terminal voltage in the rotating coordinate system into two independent first-order filters for processing, generating two corresponding filtered current signals. The two filtered current signals together constitute the damping compensation current signal. The grid-type amplitude locking control module, connected to the filter module, is used to inject the damping compensation current signal into the current reference value of the grid-type converter to enhance system stability.

6. The netting width-locking control device as described in claim 5, characterized in that: The amplitude-locking loop module is implemented using a unity negative feedback structure. Its forward channel consists of an integrator with a transfer function of 1 / s and a gain coefficient of 1 / k. ca Composed of series connection; The input terminal of the amplitude-locked loop module receives the d-axis voltage component V after dq transformation. td The estimated value of the output voltage amplitude V m And by comparing V td Compared with the estimated value V m The difference between them is used to obtain the voltage amplitude error signal V. e .

7. The netting width-locking control device as described in claim 5, characterized in that: The filter module includes: The first-order filter is used to filter the voltage amplitude error signal V. e Filtering is performed to output the q-axis damping compensation current signal. ; The second first-order filter is used to filter the q-axis voltage component V. tq Filtering is performed to output the d-axis damping compensation current signal. .

8. The netting width-locking control device as described in claim 5, characterized in that: The net-structure width-locking control module includes: The current reference correction unit is used to convert the damping compensation current signal , A new reference current signal is obtained by injecting it into the initial reference current signal output by the voltage control loop; A current control unit is used to generate a reference internal potential signal based on the new reference current signal; The coordinate transformation unit is used to convert the reference internal potential signal into a modulation signal in a three-phase stationary coordinate system and input it into the PWM generator.

9. A net-locking control system, characterized in that: It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the meshing and width-locking control method as described in any one of claims 1-4.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the meshing and width-locking control method as described in any one of claims 1-4.

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