Transient synchronous control method and device for adaptive power angle and angular velocity deviation

Abstract

The invention discloses a transient synchronous control method and device for adaptive power angle and angular velocity deviation, and relates to the technical field of power system stability control. According to the method disclosed by the invention, the influence control of reactive power control on the power angle stability can be realized by constructing the dynamic equation of the network construction type converter containing the influence of the reactive power control loop; evaluating the stable state of the system in real time by defining a comprehensive stability index based on power angle deviation and angular velocity deviation; the damping coefficient and the reactive droop coefficient are dynamically adjusted by designing an adaptive control law, so that the power angle stability is effectively enhanced and the recovery process is accelerated when transient disturbance occurs in the system.

Description

Technical Field

[0001] This invention discloses a transient synchronization control method and device for adaptive power angle and angular velocity deviation, which relates to the field of power system stability control technology. Background Technology

[0002] With the large-scale integration of renewable energy, the hybrid operation of grid-connected and grid-connected converters in power systems has become a typical scenario. In such hybrid systems, the transient power angle stability of the system faces severe challenges when grid faults occur (such as three-phase short circuits). In existing technologies, grid-connected converters typically employ a virtual synchronous machine control strategy with fixed parameters, whose damping coefficient and reactive power droop coefficient remain constant during operation. However, this fixed-parameter control method has the following drawbacks: It cannot adapt to different fault scenarios: the fixed damping coefficient cannot adaptively adjust according to the severity of the fault and the system state, resulting in insufficient damping and prolonged system oscillations under certain fault conditions; it ignores the impact of the reactive power control loop: traditional analysis often ignores the impact of the reactive power control loop on power angle stability. In reality, when the grid voltage drops, the reactive power loop further affects power angle stability by adjusting the generator terminal voltage; and it has a slow recovery speed: fixed-parameter control cannot provide sufficient damping support during system transients, resulting in a slow power angle recovery process. Especially under severe grid fault conditions, existing fixed-parameter control strategies may lead to a decrease in system transient power angle stability or even system instability. Summary of the Invention

[0003] This invention addresses the problems of existing technologies by providing a transient synchronization control method and apparatus for adaptive power angle and angular velocity deviation. The technical solution adopted is as follows: Firstly, a transient synchronization control method for adaptive power angle and angular velocity deviation includes: S1. Based on the grid-type converter and the grid-connected converter, construct the dynamic equation of the grid-type converter including the reactive power loop; S2, a comprehensive stability index is defined based on the combined indexes of power angle deviation and angular velocity deviation; S3. Based on the comprehensive stability index, an adaptive control law is used to dynamically adjust the damping coefficient and reactive power droop coefficient of the grid-type converter.

[0004] In some implementations, S1 includes: S11, Based on the grid-type converter and the grid-connected converter, establish an equivalent circuit model through the hybrid system; S12, based on the change in power angle during the transient process, analyze the change in terminal voltage through the reactive power control loop; S13, based on the grid-type converter, constructs transient synchronization characteristics through rotor motion equations.

[0005] In some implementations, S2 includes: S21, angular work angle deviation The angular velocity deviation ( ); S22, the comprehensive stability index is a weighted combination of power angle deviation and angular velocity deviation ( ).

[0006] In some implementations, S3 includes: S31, The damping coefficient and reactive power droop coefficient are dynamically adjusted according to the comprehensive stability index; S32, Adaptive control of the power angle stability is performed based on the transient disturbance of the hybrid system.

[0007] In some implementations, S31 includes: S311, when the angle deviation or angular velocity deviation is too large, the damping coefficient is automatically increased and adjusted based on the deviation. S312, when the power angle deviation increases, the reactive power droop coefficient is automatically reduced and adjusted based on the deviation.

[0008] Secondly, embodiments of the present invention provide a transient synchronization control device for adaptive power angle and angular velocity deviation, comprising: The equation construction module is used to construct dynamic equations for grid-type converters, including reactive power loops, based on grid-type and grid-connected converters. The index construction module is used to define a comprehensive stability index based on the combined indices of power angle deviation and angular velocity deviation. The dynamic adjustment module is used to dynamically adjust the damping coefficient and reactive power droop coefficient of the grid-type converter based on the comprehensive stability index and an adaptive control law.

[0009] In some implementations, the equation construction module includes: Equivalent model unit, used to establish equivalent circuit model through hybrid system based on the grid-type converter and the grid-connected converter; The voltage analysis unit is used to analyze the changes in the generator terminal voltage based on the power angle changes during the transient process through the reactive power control loop; The characteristic synchronization unit is used to construct transient synchronization characteristics based on the rotor motion equation of the grid-connected converter.

[0010] In some implementations, the dynamic adjustment module includes: A stabilization adjustment unit is used to dynamically adjust the damping coefficient and reactive power droop coefficient according to the comprehensive stability index. An adaptive adjustment unit is used to adaptively control the power angle stability according to the transient disturbance of the hybrid system.

[0011] Thirdly, embodiments of the present invention provide an electronic device, including a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein when the one or more computer instructions are executed by the processor, they implement the method described in the first aspect above. Fourthly, embodiments of the present invention provide a computer storage medium, wherein a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a processor, it implements the method described in the first aspect.

[0012] One or more embodiments of the present invention can bring at least the following beneficial effects: This invention constructs dynamic equations for a grid-connected converter that incorporates the influence of a reactive power control loop, enabling control over the impact of reactive power control on power angle stability. It defines a comprehensive stability index based on power angle deviation and angular velocity deviation for real-time evaluation of the system's stable state. By designing an adaptive control law to dynamically adjust the damping coefficient and reactive power droop coefficient, it effectively enhances power angle stability and accelerates the recovery process during transient disturbances. This invention can automatically adjust control parameters according to the actual operating state of the system and the severity of the fault, adapting to different fault scenarios, effectively suppressing system oscillations, reducing the maximum power angle deviation, and significantly improving the transient stability of a hybrid grid-connected converter system. Simulation results show that when a three-phase short-circuit fault occurs in the power grid, the control strategy proposed in this invention can reduce the maximum power angle deviation and significantly reduce the duration of oscillations, enhancing the effectiveness and superiority of this invention. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a flowchart of the transient synchronization control method for adaptive power angle and angular velocity deviation provided in an embodiment of the present invention; Figure 2 This is the equivalent circuit diagram of the hybrid system provided in the embodiments of the present invention; Figure 3 This is a voltage vector relationship diagram provided in an embodiment of the present invention; Figure 4 This is a phase plane diagram of GFM when the fault time is relatively long (0.3s) according to an embodiment of the present invention; Figure 5 This is a phase plane diagram of GFM when the fault time is short (0.15s) according to an embodiment of the present invention; Figure 6 This is provided by the embodiments of the present invention. K q Phase plane diagrams of GFM with different damping coefficients when = 0.1; Figure 7 This is provided by the embodiments of the present invention. K q Phase plane diagrams of GFM with different damping coefficients at a value of 0.4 Figure 8 This is a control block diagram of the control strategy of the present invention provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the power angle response curve after applying the control of the present invention, provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of the power angle response curve when the control of the present invention is not applied, provided in an embodiment of the present invention. Detailed Implementation

[0015] 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, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0016] Example 1: Figure 1 A flowchart of a transient synchronization control method for adaptive power angle and angular velocity deviation is shown, as follows: Figure 1 As shown, the transient synchronization control method for adaptive power angle and angular velocity deviation provided in this embodiment includes: S1. Based on the grid-type converter and the grid-connected converter, construct the dynamic equation of the grid-type converter including the reactive power loop; S2, a comprehensive stability index is defined based on the combined indexes of power angle deviation and angular velocity deviation; S3. Based on the comprehensive stability index, an adaptive control law is used to dynamically adjust the damping coefficient and reactive power droop coefficient of the grid-type converter.

[0017] According to S1, specifically including: S11, establishing an equivalent circuit model through a hybrid system based on the grid-connected converter and the grid-connected converter; S12, analyzing the change in terminal voltage through a reactive power control loop based on the change in power angle during the transient process; S13, constructing transient synchronization characteristics through rotor motion equations based on the grid-connected converter.

[0018] The dynamic equations of a grid-connected converter that do not consider the influence of reactive power loops are constructed. This is based on the equivalent circuit of the grid-connected hybrid system (…). Figure 2 ) and voltage vector relationship ( Figure 3 ( ), Derive the expression for the active power output of the GFM and analyze the influence of the damping coefficient on system stability; The dynamic equations of a grid-connected converter considering the influence of the reactive power control loop are constructed. The impact mechanism of the reactive power control loop on the GFM terminal voltage and output power is analyzed using phase plane diagrams. Figure 6 , Figure 7 Verify the deteriorating effect of the reactive power loop on transient power angle stability; The dynamic equations for a grid-connected converter, neglecting reactive power loops, are constructed. Since the external characteristics of a GFM can be equivalent to a voltage source, and the external characteristics of a GFL during a fault are equivalent to a current source, the system can be represented as a scenario with one voltage source and one current source connected in parallel. The equivalent circuit of this system is as follows: Figure 2 As shown, where Y GFL , Y GFM and Y P These are the admittances of their respective lines.

[0019] With grid voltage vector U g As a reference vector, Figure 3 Provide a vector diagram showing the terminal voltage relationships of each generator unit. d GFL and d GFM The angle difference between GFL and GFM relative to the common reference frame can be defined as the power angle of each generating unit. The equivalent current source amplitude is... I GFL The phase angle is d GFL + q IGFL ,in q IGFL =arctan( I GFL_q / I GFL_d ).

[0020] Construct the voltage network equations for the hybrid grid system, in equation (1)I 1. I 2 and I 3 represents the injected currents at nodes 1, 2, and 3, respectively.

[0021] (1) For ease of subsequent analysis, some expressions are defined as follows: (2) By combining the system network equations and the complex power calculation formula, the output power of the GFM can be derived: (3) (4) In formula (3), the first two terms are the active power output of the single-unit grid-connected system, and the third term is the active power coupling term, which characterizes the influence of GFL on the output power of GFM.

[0022] The transient synchronization characteristics of GFM are described based on the second-order rotor equation motion characteristics shown in equation (5).

[0023] (5) (6) In the formula: and These are active and reactive power commands, respectively. P GFM and Q GFM These represent the actual output values ​​of active and reactive power, respectively. J GFM and D GFM For virtual inertia and damping coefficients; K q This refers to the proportional coefficient of the reactive power control loop. U ref This is the rated voltage amplitude.

[0024] Through the above derivation, the dynamic equation for GFM was obtained, and the damping coefficient was analyzed. D GFM The impact on system stability. Figure 4 and Figure 5 As can be seen from the phase plane diagram, a larger damping coefficient is beneficial to power angle stability.

[0025] The dynamic equations of the grid-type converter considering the reactive power loop are constructed, and further derivation can be obtained by combining formula (6) and formula (4). U GFM Regarding the relationship of the power angle: (7) As can be seen from equation (7), the terminal voltage amplitude of GFM U GFM It is not a constant value; in addition to its own control parameters and network impedance, it will also be affected by the operating status of the GFL and the grid voltage. Substituting formula (7) into formula (3), we obtain the expression for the active power output of the GFM: (8) in a , b , c and d The expressions are as follows: (9) Draw the phase plane based on formula (8). Figure 6 and Figure 7 .observe Figure 6 and Figure 7 Compare the deviation of the work angle ( d = d max - 0), with a longer downtime and a larger reactive power regulation coefficient. kq Under these circumstances, the angle of force deviation d The larger the value, the more it indicates that the reactive power loop will worsen the transient power angle stability of the VSG. When the grid voltage drops, if the effect of the reactive power loop is ignored and assumed... U GFM If it remains unchanged, the transient stability assessment results will be overly optimistic. In fact, U GFM Under the action of the reactive power ring, it will follow U g The effect of the reactive power loop on the transient power angle stability of the VSG must be analyzed. The results show that increasing the damping and decreasing the reactive power regulation coefficient are beneficial to power angle stability.

[0026] Next, according to S2, define the stability index: S21, angular work angle deviation The angular velocity deviation ( ); S22, the comprehensive stability index is a weighted combination of power angle deviation and angular velocity deviation ( ).

[0027] The next step, according to S3, includes: S31, Based on the comprehensive stability index, the damping coefficient and reactive power droop coefficient are dynamically adjusted; S32, Adaptive control of the power angle stability is performed based on the transient disturbance of the hybrid system.

[0028] In some implementations, S31 includes: S311, when the angle deviation or angular velocity deviation is too large, the damping coefficient is automatically increased and adjusted based on the deviation. S312, when the power angle deviation increases, the reactive power droop coefficient is automatically reduced and adjusted based on the deviation; the damping coefficient D FGM The adjustment method is as follows: ; in D FGM (0) is the initial damping coefficient. K D To adjust the gain; S311, When the angle deviation or angular velocity deviation is too large, the adaptive control method will automatically increase the value according to the deviation. D FGM To enhance system damping.

[0029] The reactive power droop coefficient K FGM The adjustment method is as follows: ; in K FGM (0) represents the initial reactive power droop coefficient. K K To adjust the gain; S312, when the power angle deviation increases, decrease K FGM To reduce the adverse effects of the reactive power loop on power angle stability The control strategy is based on adaptive adjustment of the damping coefficient according to the power angle deviation and angular velocity deviation. D FGM With reactive power droop coefficient K FGM Improve the stability of system transient synchronization: (10) Figure 8 The control block diagram of the control strategy presented in this paper is given. By adding an adaptive compensation phase, a larger damping coefficient can be provided when the power angle and angular velocity are too large, thereby accelerating energy consumption, speeding up the power angle recovery process, and improving transient synchronization stability.

[0030] In a specific embodiment, a three-phase short-circuit fault is set, with a fault duration of 0.15s and a total simulation duration of 10s. After fault clearance, transient synchronous stabilization is implemented, with the following control parameters: K D =200; KK =2; K w = 0.05. According to Figure 9 From the phase plane diagram, the maximum power angle deviation after control is obtained: 0.0895 rad. (Compared to...) Figure 10 The maximum power angle deviation without adaptive control is 0.095 rad, and the proposed control can improve power angle stability. A three-phase short-circuit fault was set up; after the fault was cleared, control was not applied, and the oscillation duration increased after the fault, verifying the feasibility of the control.

[0031] Example 2: Secondly, embodiments of the present invention provide a transient synchronization control device for adaptive power angle and angular velocity deviation, comprising: The equation construction module is used to construct dynamic equations for grid-type converters, including reactive power loops, based on grid-type and grid-connected converters. The index construction module is used to define a comprehensive stability index based on the combined indices of power angle deviation and angular velocity deviation. The dynamic adjustment module is used to dynamically adjust the damping coefficient and reactive power droop coefficient of the grid-type converter based on the comprehensive stability index and an adaptive control law.

[0032] Furthermore, the equation construction module includes: Equivalent model unit, used to establish equivalent circuit model through hybrid system based on the grid-type converter and the grid-connected converter; The voltage analysis unit is used to analyze the changes in the generator terminal voltage based on the power angle changes during the transient process through the reactive power control loop; The characteristic synchronization unit is used to construct transient synchronization characteristics based on the rotor motion equation of the grid-connected converter.

[0033] Furthermore, the dynamic adjustment module includes: A stabilization adjustment unit is used to dynamically adjust the damping coefficient and reactive power droop coefficient according to the comprehensive stability index. An adaptive adjustment unit is used to adaptively control the power angle stability according to the transient disturbance of the hybrid system.

[0034] Example 3: This embodiment also provides an electronic device, including a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the method of Embodiment 1; In practical applications, the processor can be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller unit (MCU), microprocessor, or other electronic components to execute the methods described in the above embodiments.

[0035] The method implemented in this embodiment is as shown in Embodiment 1.

[0036] Example 4: This embodiment also provides a computer storage medium, in which a computer program is stored, and when the computer program is executed by one or more processors, it implements the method of embodiment one. The computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0037] The method implemented in this embodiment is as shown in Embodiment 1.

[0038] In the several embodiments provided in this invention, it should be understood that the disclosed systems and methods can also be implemented in other ways. The system and method embodiments described above are merely illustrative.

[0039] It should be noted that, in this document, the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A transient synchronization control method for adaptive work angle and angular velocity deviation, characterized in that, include: S1. Based on the grid-type converter and the grid-connected converter, construct the dynamic equation of the grid-type converter including the reactive power loop; S2, a comprehensive stability index is defined based on the combined indexes of power angle deviation and angular velocity deviation; S3. Based on the comprehensive stability index, an adaptive control law is used to dynamically adjust the damping coefficient and reactive power droop coefficient of the grid-type converter.

2. The method according to claim 1, characterized in that, S1 includes: S11, Based on the grid-type converter and the grid-connected converter, establish an equivalent circuit model through the hybrid system; S12, based on the change in power angle during the transient process, analyze the change in terminal voltage through the reactive power control loop; S13, based on the grid-type converter, constructs transient synchronization characteristics through rotor motion equations.

3. The method according to claim 1, characterized in that, S2 include: S21, angular work angle deviation The angular velocity deviation ( ); S22, the comprehensive stability index is a weighted combination of power angle deviation and angular velocity deviation ( ).

4. The method according to claim 2, characterized in that, S3 include: S31, The damping coefficient and reactive power droop coefficient are dynamically adjusted according to the comprehensive stability index; S32, Adaptive control of the power angle stability is performed based on the transient disturbance of the hybrid system.

5. The method according to claim 4, characterized in that, S31 includes: S311, when the angle deviation or angular velocity deviation is too large, the damping coefficient is automatically increased and adjusted based on the deviation. S312, when the power angle deviation increases, the reactive power droop coefficient is automatically reduced and adjusted based on the deviation.

6. A transient synchronization control device for adaptive work angle and angular velocity deviation, characterized in that, include: The equation construction module is used to construct dynamic equations for grid-type converters, including reactive power loops, based on grid-type and grid-connected converters. The index construction module is used to define a comprehensive stability index based on the combined indices of power angle deviation and angular velocity deviation. The dynamic adjustment module is used to dynamically adjust the damping coefficient and reactive power droop coefficient of the grid-type converter based on the comprehensive stability index and an adaptive control law.

7. The apparatus according to claim 6, characterized in that, The equation construction module includes: Equivalent model unit, used to establish equivalent circuit model through hybrid system based on the grid-type converter and the grid-connected converter; The voltage analysis unit is used to analyze the changes in the generator terminal voltage based on the power angle changes during the transient process through the reactive power control loop; The characteristic synchronization unit is used to construct transient synchronization characteristics based on the rotor motion equation of the grid-connected converter.

8. The apparatus according to claim 7, characterized in that, The dynamic adjustment module includes: A stabilization adjustment unit is used to dynamically adjust the damping coefficient and reactive power droop coefficient according to the comprehensive stability index. An adaptive adjustment unit is used to adaptively control the power angle stability according to the transient disturbance of the hybrid system.

9. An electronic device, characterized in that, The system includes a memory and a processor, the memory being used to store one or more computer instructions, wherein the one or more computer instructions, when executed by the processor, implement the method as described in any one of claims 1-5.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, is used to implement the method as described in any one of claims 1-5.

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