Active frequency support synchronous control method for high-voltage direct-current converter valve and related device

Abstract

The application discloses a kind of active frequency support synchronous control method of high-voltage direct-current converter valve and related equipment, it is related to direct current transmission control technical field.The method comprises: obtaining the three-phase voltage signal of the alternating current network connected to high-voltage direct-current converter valve, and three-phase voltage signal is converted into orthogonal voltage component under two-phase stationary coordinate system;Based on orthogonal voltage component and the virtual oscillator state variable of high-voltage direct-current converter valve, calculate error tracking item;Based on error tracking item, at least one of the frequency inertia coefficient, damping coefficient and synchronous gain control parameter is combined, to calculate the internal frequency state of high-voltage direct-current converter valve, and synchronous gain control parameter is used to adjust convergence speed;Based on internal frequency state calculation synchronous phase reference signal, and based on synchronous phase reference signal, generate the valve control signal of high-voltage direct-current converter valve.According to the embodiment of the application, active frequency support and improve weak network stable operation ability can be realized.

Description

Technical Field

[0001] This application belongs to the field of DC power transmission control technology, and in particular relates to an active frequency support synchronization control method and related equipment for a high-voltage DC converter valve. Background Technology

[0002] Conventional high-voltage direct current (HVDC) transmission technology has been widely used globally due to its superior economic efficiency and high reliability. However, this technology relies on grid voltage for commutation, and the synchronous triggering of the converter valves depends entirely on a phase-locked loop (PLL) for closed-loop tracking of the AC voltage phase and frequency. In terms of control strategy, HVDC rectifiers typically employ constant DC current control to track power commands. This results in a dynamic physical decoupling between the DC station and the system frequency. The PLL only eliminates phase errors and does not inject inertial or damping power into the system. When the grid short-circuit ratio decreases or the renewable energy penetration rate increases, leading to a reduction in frequency margin, the converter valves maintain their inherent power settings. They cannot actively adjust the frequency and are susceptible to voltage transients caused by renewable energy fluctuations, potentially leading to commutation failure. Furthermore, the priority of the polarity control trigger angle lies in commutation safety and harmonic suppression, rather than frequency support, which further limits the potential of conventional DC in terms of frequency stability.

[0003] With the large-scale grid connection of renewable energy through power electronic converters, the system's equivalent rotational inertia continues to decrease, the rate of change of frequency (RoCoF) rises, and the frequency trough deepens, increasingly limiting the timeliness of traditional primary frequency regulation and load shedding strategies. While conventional DC transmission holds a backbone position for long-distance, high-power transmission, its constant power and constant current control paradigm lacks dynamic inertia and damping support mechanisms. In weak grids or scenarios with large disturbances, this may amplify frequency deviations and exacerbate system frequency stability risks. Therefore, systematically exploring the active frequency support potential of conventional DC transmission technology, upgrading it from a passive transmission channel to a system-friendly frequency regulation unit, has become a key requirement for the safe and stable operation of highly penetrated renewable energy grids. Summary of the Invention

[0004] This application provides an active frequency support synchronization control method and related equipment for a high-voltage DC converter valve, which can realize active frequency support and improve the stable operation capability of weak grids.

[0005] In a first aspect, embodiments of this application provide an active frequency support synchronization control method for a high-voltage DC converter valve, the active frequency support synchronization control method for the high-voltage DC converter valve comprising: The three-phase voltage signal of the AC power grid connected to the high-voltage DC converter valve is obtained and converted into orthogonal voltage components in a two-phase stationary coordinate system. The error tracking term is calculated based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve; Based on the error tracking term, and combined with at least one of the preset frequency inertia coefficient, damping coefficient and synchronous gain control parameters, the internal frequency state of the high voltage DC converter valve is calculated. The synchronous gain control parameters are used to adjust the convergence speed. The synchronization phase reference signal is calculated based on the internal frequency state, and the valve control signal of the high-voltage DC converter valve is generated based on the synchronization phase reference signal.

[0006] In some possible implementations, after calculating the internal frequency state of the high-voltage DC converter valve, the active frequency support synchronization control method for the high-voltage DC converter valve further includes: Update the virtual oscillator state variables based on the internal frequency state and the virtual oscillator state variables, and... Returning to the step of calculating the error tracking term based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, the internal frequency state of the high-voltage DC converter valve is updated.

[0007] In some possible implementations, the virtual oscillator state variables are updated based on the internal frequency state and the virtual oscillator state variables, including: The virtual oscillator state variables are updated based on the nonlinear limit cycle oscillator equation, according to the internal frequency state and the virtual oscillator state variables. The equations for the nonlinear limit ring oscillator include:

[0008] in, , For virtual oscillator state variables, A For the amplitude of the virtual oscillator, This refers to the internal frequency state.

[0009] In some possible implementations, the error tracking term is calculated based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, including: Based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, the error tracking term is calculated using a preset error calculation formula; the error calculation formula includes:

[0010] in, , For virtual oscillator state variables, , These are orthogonal voltage components. This is the error tracking term.

[0011] In some possible implementations, the internal frequency state of the high-voltage DC converter valve is calculated based on the error tracking term, combined with at least one of the preset frequency inertia coefficient, damping coefficient, and synchronous gain control parameters, including: Based on the error tracking term, and combined with at least one of the frequency inertia coefficient, damping coefficient, and synchronous gain control parameters, calculate the differential value of the internal frequency state. The internal frequency state is determined based on the differential value of the internal frequency state.

[0012] In some possible implementations, the differential value of the internal frequency state is calculated based on the error tracking term, combined with at least one of the frequency inertia coefficient, damping coefficient, and synchronization gain control parameters, including: Based on the error tracking term, and combined with the frequency inertia coefficient, damping coefficient, and synchronization gain control parameters, the differential value of the internal frequency state is calculated through a preset first-order frequency dynamic equation; the first-order frequency dynamic equation includes:

[0013] in, For error tracking, H The frequency inertia coefficient, D The damping coefficient is... For reference, the rated frequency, These are the synchronization gain control parameters. This refers to the internal frequency state.

[0014] In some possible implementations, the frequency inertia coefficient satisfies a first constraint relationship, the damping coefficient satisfies a second constraint relationship, and / or, the synchronization gain control parameter satisfies a third constraint relationship; The first constraint relationship includes: The second constraint relationship includes: The third constraint relationship includes: in, H The frequency inertia coefficient, D The damping coefficient is... These are the synchronization gain control parameters. This is the design value for the maximum frequency error; This represents the maximum rate of change of the power grid frequency. The phase angle difference at the steady-state operating point or the maximum permissible linearized phase shift; It is the maximum permissible dynamic phase margin; It is the synchronous stiffness coefficient. This represents the minimum voltage amplitude of the power grid.

[0015] In some possible implementations, the frequency inertia coefficient and the damping coefficient satisfy a first constraint condition corresponding to the natural angular frequency, and / or, the frequency inertia coefficient and the damping coefficient satisfy a second constraint condition corresponding to the damping ratio. The first constraint includes: , The range of values ​​is ; The second constraint includes: , The value range is 0.6 to 0.8; in, H The frequency inertia coefficient, D The damping coefficient is... It is the natural angular frequency. These are the synchronization gain control parameters. This is the initial phase of the phase-locked loop. is the damping ratio.

[0016] Based on the same inventive concept, in a second aspect, embodiments of this application provide an active frequency support synchronization control device for a high-voltage DC converter valve, the active frequency support synchronization control device for the high-voltage DC converter valve comprising: The acquisition module is used to acquire the three-phase voltage signal of the AC power grid connected to the high-voltage DC converter valve and convert the three-phase voltage signal into orthogonal voltage components in a two-phase stationary coordinate system. The first calculation module is used to calculate the error tracking term based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve; The second calculation module is used to calculate the internal frequency state of the high voltage DC converter valve based on the error tracking term and in combination with at least one of the preset frequency inertia coefficient, damping coefficient and synchronous gain control parameters. The synchronous gain control parameters are used to adjust the convergence speed. The generation module is used to calculate the synchronization phase reference signal based on the internal frequency state, and generate the valve control signal of the high voltage DC converter valve based on the synchronization phase reference signal.

[0017] Thirdly, embodiments of this application provide an active frequency support synchronization control device for a high-voltage DC converter valve, the active frequency support synchronization control device for the high-voltage DC converter valve comprising: Processor and memory storing computer program instructions; When the processor executes the computer program instructions, it implements the active frequency support synchronization control method for the high-voltage DC converter valve provided in any of the embodiments of this application above.

[0018] Fourthly, embodiments of this application provide a computer storage medium storing computer program instructions, which, when executed by a processor, implement the active frequency support synchronization control method for a high-voltage DC converter valve as provided in any of the embodiments of this application above.

[0019] Fifthly, embodiments of this application provide a computer program product in which instructions, when executed by a processor of an electronic device, cause the electronic device to perform an active frequency support synchronization control method for a high-voltage DC converter valve as provided in any of the embodiments of this application described above.

[0020] This application provides an active frequency support synchronization control method and related equipment for a high-voltage direct current (HVDC) converter valve. The method acquires the three-phase voltage signal of the AC power grid connected to the HVDC converter valve and converts it into orthogonal voltage components in a two-phase stationary coordinate system, thus establishing a direct coupling relationship with the grid voltage. Based on this, an error tracking term is calculated using the orthogonal voltage components and the virtual oscillator state variables of the HVDC converter valve. This error tracking term reflects the real-time deviation between the grid voltage and the internal oscillation state, providing a basis for subsequent dynamic frequency adjustment. Next, based on the error tracking term and at least one of the preset frequency inertia coefficient, damping coefficient, and synchronization gain control parameters used to adjust the convergence speed, the internal frequency state of the HVDC converter valve is calculated. This allows the internal frequency state to adaptively adjust according to grid frequency disturbances, simulating the rotor motion characteristics of a synchronous generator. Subsequently, a synchronization phase reference signal is calculated based on the internal frequency state, and a valve control signal for the HVDC converter valve is generated based on the synchronization phase reference signal. This triggers phase adjustment to achieve dynamic frequency adjustment, realizing the physical coupling of power response and frequency change.

[0021] As described above, the embodiments of this application replace the passive tracking of the external voltage phase by the traditional phase-locked loop by dynamically synchronizing the synchronization phase reference signal with the power grid. This technology directly responds to the power grid voltage waveform and autonomously generates a synchronization phase reference signal that is both synchronized with the power grid and contains controllable dynamic characteristics (frequency inertia coefficient, damping coefficient, and synchronization gain control parameters for adjusting convergence speed). This improves synchronization robustness under non-ideal voltage conditions and reduces the risk of commutation failure due to synchronization errors. Simultaneously, by mapping power grid frequency disturbances to changes in internal frequency states, the valve control signal is directly adjusted, enabling the DC converter valve to have a rapid active power support response capability to frequency deviations and rates of change, achieving the inertia support and damping regulation functions of a synchronous machine. Compared with the prior art, the active frequency support synchronization control method and related equipment for a high-voltage DC converter valve in this application embodiment can achieve the above functions by replacing the polarity control synchronization loop without adding additional hardware equipment. It can solve the technical problems of conventional DC converter valves being unable to operate stably in weak grid environments and receiving-end converter valves lacking frequency support capabilities at low cost, effectively improving the safe and stable operation level of renewable energy grids, and realizing active frequency support and improving the stable operation capability in weak grids at low cost. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart illustrating an embodiment of the active frequency support synchronization control method for a high-voltage DC converter valve provided in this application. Figure 2 This is a schematic diagram illustrating the principle of an active frequency support synchronization control method for a high-voltage DC converter valve provided in an embodiment of this application. Figure 3 This is a schematic diagram comparing the active frequency support synchronization control method for a high-voltage DC converter valve provided in one embodiment of this application with the traditional PLL control method; Figure 4 This is a schematic diagram comparing the active frequency support synchronization control method for a high-voltage DC converter valve under extremely weak grid conditions provided in an embodiment of this application with the traditional PLL control method; Figure 5 This is an active-frequency droop characteristic diagram of the active frequency support synchronization control method for a high-voltage DC converter valve provided in an embodiment of this application. Figure 6 This is a schematic diagram of the active frequency support synchronization control device for a high-voltage DC converter valve provided in one embodiment of this application; Figure 7 This is a schematic diagram of the active frequency support synchronization control device for a high-voltage DC converter valve provided in one embodiment of this application. Detailed Implementation

[0024] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0025] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0026] As described in the background section, systematically exploring the active frequency support potential of conventional DC transmission technology, and upgrading it from a passive transmission channel to a system-friendly frequency regulation unit, has become a key requirement for the safe and stable operation of high-penetration renewable power grids.

[0027] Specifically, from the perspective of existing frequency support methods, the primary frequency regulation of synchronous generators is limited by the continuously declining output limit of the units and the grid connection ratio, while the rapid frequency response of energy storage faces high cost constraints, and demand-side regulation suffers from insufficient load availability and reliability. In contrast, existing conventional DC transmission has significant advantages such as large capacity, critical geographical layout, mature technology, and low unit cost. If it can be endowed with active frequency support capabilities, it can effectively suppress the rate of change of frequency (RoCoF) and reduce frequency troughs on a time scale of hundreds of milliseconds to seconds, thus securing a valuable recovery window for subsequent slow frequency regulation resources. At the same time, conventional DC converter valves with active frequency support capabilities are no longer limited to connecting to strong AC grids, but can also operate stably in renewable energy aggregation systems with extremely low short-circuit ratios or at the end of remote weak grids, significantly reducing reliance on dynamic reactive power compensation equipment, thereby significantly reducing investment costs, and effectively integrating and transmitting the potential regulation capabilities of renewable energy bases to the receiving-end system, providing key technical support for the reliable consumption of high proportions of renewable energy.

[0028] However, the generation of trigger pulses for conventional HVDC converter valves is highly dependent on the phase-locked loop (PLL) for accurate tracking of the grid voltage phase. In low short-circuit ratio and weak grid environments, the high impedance characteristics of the system amplify the disturbances to AC voltage during commutation, leading to significant commutation voltage distortion and drops. The dynamic tracking error of the PLL under non-ideal voltage conditions is directly converted into trigger phase offset, further compressing the already insufficient arc-extinguishing angle margin. Once encountering transient disturbances, it is highly susceptible to inducing commutation failure. The instantaneous overvoltages and harmonic impacts generated by commutation failures further deteriorate the grid voltage quality, disrupt the PLL's synchronization reference, and form a positive feedback instability loop that leads to continuous commutation failures or even system shutdown, threatening the safe and stable operation of the transmission system.

[0029] Furthermore, the core objective of existing conventional high-voltage direct current (HVDC) converter valves is to maintain the stable operation of the DC transmission channel. Their power control typically follows upper-level dispatch instructions or closed-loop regulation of DC voltage / current, lacking a mechanism for active power response to AC system frequency change rates or frequency deviations. Therefore, when the AC system experiences frequency drops due to disturbances, the line commutated converter (LCC) system not only fails to provide inertial support power similar to that of a synchronous generator, but may also reduce sending-end power due to protection actions or poor control system responses, thereby exacerbating system frequency imbalance. This lack of active support capability directly reduces the overall inertia level and frequency stability of power systems with a high proportion of LCCs, making it difficult to adapt to the development needs of high-proportion renewable energy grid integration.

[0030] Current research on the integration of line commutated high voltage direct current (HVDC) transmission lines into weak grids and the implementation of active frequency support mainly focuses on two directions. On the one hand, research emphasizes weak grid adaptation and stability enhancement, relying on a high short-circuit ratio to ensure commutation safety. However, in environments with low short-circuit ratios (SCR), the stability of the LCC faces significant risks. On the other hand, many studies have proposed frequency support control strategies, enhancing the frequency response capability of LCC-HVDC through rate of power compensation (RPC). However, these methods mostly focus on power compensation rather than power angle mapping simulating synchronous machines, and often employ passive response methods for frequency regulation. This fails to adequately address the coupling problem between commutation margin and frequency response. Furthermore, control delays and measurement errors can easily lead to response lag under large-scale frequency fluctuations, making it difficult to achieve fast and effective frequency support. In summary, a systematic control strategy that balances conventional DC active frequency support with adaptability to weak grid environments has not yet been formed. There is an urgent need to develop a new synchronization method that can replace PLL from the perspective of power synchronization of virtual synchronous machines, so as to break through the existing technical bottlenecks and meet the operation requirements of new power systems.

[0031] In view of the above, and addressing the issues of conventional DC converter valves failing to operate stably under weak grid conditions via PLLs and the receiving-end converter valves lacking frequency support, this application provides an active frequency support synchronization control method and related equipment for high-voltage DC converter valves. This allows conventional phase-controlled DC converter valves to achieve active frequency support and improve stable operation under weak grid conditions simply by replacing the polarity control synchronization loop, at a low cost. It should be noted that the embodiments provided in this application are not intended to limit the scope of this application.

[0032] The active frequency support synchronization control method for high-voltage DC converter valves provided in the embodiments of this application will be introduced first.

[0033] Figure 1 A schematic flowchart of an active frequency support synchronization control method for a high-voltage DC converter valve according to an embodiment of this application is shown. This active frequency support synchronization control method for a high-voltage DC converter valve is applied to electronic equipment. Figure 1 As shown, the active frequency support synchronization control method for the high-voltage DC converter valve includes the following steps: S110: Obtain the three-phase voltage signal of the AC power grid connected to the high-voltage DC converter valve, and convert the three-phase voltage signal into orthogonal voltage components in a two-phase stationary coordinate system. S120, based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, calculate the error tracking term; S130, based on the error tracking term, combined with at least one of the preset frequency inertia coefficient, damping coefficient and synchronous gain control parameters, calculates the internal frequency state of the high voltage DC converter valve. The synchronous gain control parameters are used to adjust the convergence speed. S140 calculates the synchronous phase reference signal based on the internal frequency state, and generates the valve control signal for the high-voltage DC converter valve based on the synchronous phase reference signal.

[0034] This application provides an active frequency support synchronization control method for a high-voltage direct current (HVDC) converter valve. The method acquires the three-phase voltage signal of the AC grid connected to the HVDC converter valve and converts it into orthogonal voltage components in a two-phase stationary coordinate system, thus establishing a direct coupling relationship with the grid voltage. Based on this, an error tracking term is calculated using the orthogonal voltage components and the virtual oscillator state variables of the HVDC converter valve. This error tracking term reflects the real-time deviation between the grid voltage and the internal oscillation state, providing a basis for subsequent dynamic frequency adjustment. Next, based on the error tracking term and at least one of the preset frequency inertia coefficient, damping coefficient, and synchronization gain control parameters used to adjust the convergence speed, the internal frequency state of the HVDC converter valve is calculated. This allows the internal frequency state to adaptively adjust according to grid frequency disturbances, simulating the rotor motion characteristics of a synchronous generator. Subsequently, a synchronization phase reference signal is calculated based on the internal frequency state, and a valve control signal for the HVDC converter valve is generated based on the synchronization phase reference signal. This triggers phase adjustment to achieve dynamic frequency adjustment, realizing the physical coupling of power response and frequency change.

[0035] As described above, the embodiments of this application replace the passive tracking of the external voltage phase by the traditional phase-locked loop by dynamically synchronizing the synchronization phase reference signal with the power grid. This technology directly responds to the power grid voltage waveform and autonomously generates a synchronization phase reference signal that is both synchronized with the power grid and contains controllable dynamic characteristics (frequency inertia coefficient, damping coefficient, and synchronization gain control parameters for adjusting convergence speed). This improves synchronization robustness under non-ideal voltage conditions and reduces the risk of commutation failure due to synchronization errors. Simultaneously, by mapping power grid frequency disturbances to changes in internal frequency states, the valve control signal is directly adjusted, enabling the DC converter valve to have a rapid active power support response capability to frequency deviations and rates of change, achieving the inertia support and damping regulation functions of a synchronous machine. Compared with the prior art, the active frequency support synchronization control method for a high-voltage DC converter valve in this application embodiment can achieve the above functions by replacing the polarity control synchronization loop without adding additional hardware equipment. It can solve the technical problems of conventional DC converter valves being unable to operate stably in weak grid environments and receiving-end converter valves lacking frequency support capabilities at low cost, effectively improving the safe and stable operation level of renewable energy grids, and realizing active frequency support and improving the stable operation capability in weak grids at low cost.

[0036] The specific implementation methods of steps 110 to 140 above are described in detail below. It should be noted that, for ease of understanding the control principle of the embodiments of this application, the following description of formulas is adaptable to various situations. Figure 2 , Figure 2 This is a schematic diagram illustrating the principle of an active frequency support synchronization control method for a high-voltage DC converter valve provided in one embodiment of this application.

[0037] In S110, the three-phase voltage signal of the AC power grid connected to the high-voltage DC converter valve is acquired, and the three-phase voltage signal is converted into orthogonal voltage components in a two-phase stationary coordinate system. In specific implementation, the three-phase voltage signal on the AC side of the converter valve can be acquired through a voltage transformer, and then the Clarke transform is used to convert the voltage signal in the three-phase stationary coordinate system into orthogonal voltage components in a two-phase stationary coordinate system, namely the α-axis voltage component and the β-axis voltage component.

[0038] Therefore, by converting the orthogonal voltage components in the two-phase stationary coordinate system, a direct coupling relationship with the grid voltage is established, avoiding the dependence of the traditional phase-locked loop on the ideal sinusoidal voltage, and laying the foundation for subsequent synchronous control under non-ideal voltage conditions.

[0039] This application provides an active frequency-supported synchronization control method for a high-voltage direct current converter valve, applicable to conventional high-voltage direct current systems at the sending or receiving end. In one example, the per-unit values ​​of the three-phase voltage of the power grid are collected. The Clarke transformation is performed using the following equation (1) to convert it into a two-phase stationary coordinate system voltage. and .

[0040] (1) In step S120, an error tracking term is calculated based on the quadrature voltage components and the virtual oscillator state variables of the high-voltage DC converter valve. Specifically, the quadrature voltage components obtained in step 110 are compared with the preset virtual oscillator state variables inside the high-voltage DC converter valve, and the deviation between the two is calculated as the error tracking term.

[0041] In some specific examples, the orthogonal voltage components in the two-phase stationary coordinate system will include α-axis voltage components and β-axis voltage components. Correspondingly, the virtual oscillator state variables include an internal first state variable and an internal second state variable, which correspond to the state components in the two-phase stationary coordinate system, respectively.

[0042] Therefore, by quantifying the real-time deviation between the grid voltage and the internal oscillation state in this step, the corresponding error tracking term is obtained, providing an accurate basis for subsequent dynamic frequency adjustment, so that the control of the actual valve control signal can be related to the disturbance of the grid voltage.

[0043] Optionally, according to some embodiments of this application, an error tracking term is calculated based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, including: Based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, the error tracking term is calculated using a preset error calculation formula; the error calculation formula is shown in equation (2): (2) in, , For virtual oscillator state variables, , These are orthogonal voltage components. This is the error tracking term.

[0044] In this embodiment, , This refers to the virtual oscillator state variables, corresponding to the aforementioned internal first and second state variables. This error tracking term reflects the deviation between the grid voltage and the internal virtual oscillator, helping to provide a basis for subsequent dynamic frequency adjustments.

[0045] In S130, specifically, based on the error tracking term, and combined with at least one of the preset frequency inertia coefficient, damping coefficient, and synchronous gain control parameters used to adjust the convergence speed, the internal frequency state of the high-voltage DC converter valve is calculated. This allows the internal frequency state to adaptively adjust according to grid frequency disturbances, thereby simulating the rotor motion characteristics of a synchronous generator.

[0046] It should be added that by independently adjusting parameters such as frequency inertia coefficient, damping coefficient, or synchronous gain control parameters, the frequency support strength and dynamic response speed that a conventional DC system should provide can be flexibly configured without changing the main circuit hardware of the system, so as to adapt to the access requirements of power grids of different strengths and different power grid operation specifications.

[0047] Optionally, according to some embodiments of this application, based on the error tracking term and in combination with at least one of the preset frequency inertia coefficient, damping coefficient, and synchronous gain control parameters, the internal frequency state of the high-voltage DC converter valve is calculated, including: Based on the error tracking term, and combined with at least one of the frequency inertia coefficient, damping coefficient, and synchronous gain control parameters, calculate the differential value of the internal frequency state. The internal frequency state is determined based on the differential value of the internal frequency state.

[0048] In this embodiment, by simulating the rotor motion characteristics of a synchronous generator, based on the error tracking term obtained in step S120, and combined with preset frequency inertia coefficient, damping coefficient, and synchronous gain control parameters used to adjust the convergence speed, the differential value of the internal frequency state is calculated. Based on the differential value of the internal frequency state, the corresponding internal frequency state can be determined using a numerical integration method.

[0049] Therefore, this embodiment enables the internal frequency state to adaptively adjust according to grid frequency disturbances, achieving a rapid response to the rate of frequency change. Furthermore, by independently adjusting the frequency inertia coefficient, damping coefficient, or synchronization gain control parameters, the system's equivalent inertia and damping characteristics can be flexibly configured to meet the operational requirements of different grid intensities. For example, a larger frequency inertia coefficient results in a larger equivalent rotational inertia, a smoother frequency response, and a longer support duration; a larger damping coefficient results in a stronger ability to suppress frequency deviations and faster dynamic oscillation decay.

[0050] Optionally, according to some embodiments of this application, based on the error tracking term, and in combination with at least one of the frequency inertia coefficient, damping coefficient, and synchronization gain control parameters, the differential value of the internal frequency state is calculated, including: Based on the error tracking term, and combined with the frequency inertia coefficient, damping coefficient, and synchronization gain control parameters, the differential value of the internal frequency state is calculated through a preset first-order frequency dynamic equation; the first-order frequency dynamic equation includes: (3) in, For error tracking, H The frequency inertia coefficient, D The damping coefficient is... For reference, the rated frequency, These are the synchronization gain control parameters. This refers to the internal frequency state.

[0051] In this embodiment, the error tracking term obtained in step S120 is input into the first-order frequency dynamic equation. Combined with preset frequency inertia coefficients, damping coefficients, and synchronization gain control parameters used to adjust the convergence speed, the differential value of the internal frequency state is calculated. In this way, through the aforementioned first-order frequency dynamic equation, the inertial response and damping characteristics of the synchronous generator are actively simulated, enabling the internal frequency state to adaptively adjust according to grid frequency disturbances and achieve rapid response to the rate of frequency change.

[0052] Furthermore, by setting frequency inertia parameters and damping coefficients, conventional DC systems can simulate synchronous generators and autonomously and rapidly adjust their power exchange when the grid frequency is disturbed, thereby providing active frequency support for the grid and suppressing frequency oscillations.

[0053] In S140, specifically, the internal frequency state updated in step S130 is integrated to obtain the synchronization phase reference signal, for example, combined with... Figure 2 As shown, This refers to the internal frequency state (estimated angular frequency), achieved through... Integration (1 / s represents the integrator) yields the synchronous phase reference signal. Next, using this synchronous phase reference signal as a reference, the pulse trigger, combined with a preset conduction angle... This generates the trigger pulse signal for the thyristor of the converter valve.

[0054] Therefore, by dynamically mapping the frequency directly to trigger phase adjustment, the high-voltage DC converter valve possesses active frequency support capability. Simultaneously, through a virtual oscillator self-synchronization mechanism, the dependence of the traditional PLL on ideal grid voltage is replaced, enabling stable synchronization under weak grid conditions and reducing the risk of commutation failure.

[0055] Optionally, according to some embodiments of this application, after calculating the internal frequency state of the high-voltage DC converter valve, the active frequency support synchronization control method for the high-voltage DC converter valve further includes: Update the virtual oscillator state variables based on the internal frequency state and the virtual oscillator state variables, and... Returning to the step of calculating the error tracking term based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, the internal frequency state of the high-voltage DC converter valve is updated.

[0056] In this embodiment, combined with Figure 2 The principle shown is to update the virtual oscillator state variables based on the internal frequency state and the virtual oscillator state variables, and return to the step of calculating the error tracking term based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, so as to update the internal frequency state of the high-voltage DC converter valve, thereby forming a closed-loop iterative calculation to ensure the continuous synchronization between the internal virtual oscillator state and the grid dynamics.

[0057] Optionally, according to some embodiments of this application, updating the virtual oscillator state variables based on the internal frequency state and the virtual oscillator state variables includes: The virtual oscillator state variables are updated based on the nonlinear limit cycle oscillator equation, according to the internal frequency state and the virtual oscillator state variables. The equations for the nonlinear limit ring oscillator include: (4) in, , For virtual oscillator state variables, A For the amplitude of the virtual oscillator, This refers to the internal frequency state.

[0058] In this embodiment, combined with Figure 2 As shown, the implementation of this closed-loop iterative mechanism is to input the currently calculated internal frequency state and the virtual oscillator state variables into the nonlinear limit loop oscillator equation to generate updated virtual oscillator state variables. Then, the updated virtual oscillator state variables and the acquired orthogonal voltage components are used to recalculate the error tracking term, thereby updating the internal frequency state again, forming a continuous loop dynamic calculation process.

[0059] This ensures real-time synchronization between the internal oscillation state and the grid voltage, enabling the system to continuously track dynamic changes in the grid frequency and maintain synchronization stability during disturbances. The phase is generated through this nonlinear limit-ring oscillator equation, possessing inherent amplitude stability and phase generation capability, and the synchronization gain control parameters further enhance this capability. Adjusting the coupling strength with the power grid. When disturbances such as grid voltage distortion, sag, or phase jump occur, it exhibits stronger robustness and smoother phase tracking performance compared to traditional phase-locked loops, reducing the risk of commutation failure due to inaccurate synchronization signals.

[0060] Meanwhile, the virtual oscillator self-synchronization mechanism replaces the traditional phase-locked loop's dependence on the ideal grid voltage. The update of the virtual oscillator's state variables does not directly depend on the instantaneous phase of the grid voltage, but rather on the autonomous oscillation driven by the internal frequency state. The grid voltage only indirectly affects the internal frequency state through the error tracking term, which can maintain stable synchronization in a weak grid environment and reduce the risk of commutation failure.

[0061] Optionally, according to some embodiments of this application, the frequency inertia coefficient satisfies a first constraint relationship, the damping coefficient satisfies a second constraint relationship, and / or, the synchronization gain control parameter satisfies a third constraint relationship; The first constraint relationship includes: (5) The second constraint relationship includes: (6) The third constraint relationship includes: (7) in, H The frequency inertia coefficient, D The damping coefficient is... These are the synchronization gain control parameters. This is the design value for the maximum frequency error; This represents the maximum rate of change of the power grid frequency. The phase angle difference at the steady-state operating point or the maximum permissible linearized phase shift; It is the maximum permissible dynamic phase margin; It is the synchronous stiffness coefficient. This represents the minimum voltage amplitude of the power grid.

[0062] In this embodiment, The design value for the maximum frequency error is usually taken as... . The maximum rate of change of the power grid frequency characterizes the drastic degree of dynamic change in the power grid frequency. It is the synchronous stiffness coefficient, usually equal to It can be designed according to needs.

[0063] Equations (5), (6), and (7) provide clear tuning boundaries for the frequency inertia coefficient, damping coefficient, and synchronization gain control parameters, forming the frequency-power angle stability region. This represents the theoretical limit for parameter tuning and safe system operation. To ensure system synchronization under maximum frequency deviation and maximum frequency change rate, the grid voltage must drop to the minimum voltage amplitude. Under operating conditions, if it is possible to lock, for example If the grid frequency deviation is such that the synchronization gain control parameters must satisfy the third constraint relationship (7) mentioned above. Considering the dynamic damping characteristics and inertial tracking capability, the expression of the boundary of the synchronization gain control parameters can be found in the first constraint relationship (5) and the second constraint relationship (6) mentioned above.

[0064] By applying the above constraint relationships, parameter optimization design is achieved, directly linking performance indicators such as virtual inertia and damping coefficient with the physical safety margin of the converter. This provides a quantifiable design basis for tuning the synchronous gain control parameters under different grid strengths and application scenarios, thereby helping to improve the reliability of operation under the above parameter design.

[0065] Optionally, it should be added that when the grid frequency Not equal to the reference rated frequency At that time, the system had a phase difference problem. : (8) Therefore, the steady-state phase error generated during frequency offset will be directly and equally subtracted from the target value of the arc extinction angle of a conventional DC controller, thereby reducing the system's commutation failure safety margin. The maximum phase difference of the system must be less than the safety margin set by the conventional DC controller, i.e. , This represents the maximum commutation margin for conventional DC transmission, corresponding to the maximum permissible dynamic phase angle margin in the aforementioned formula.

[0066] Optionally, according to some embodiments of this application, the frequency inertia coefficient and the damping coefficient satisfy a first constraint condition corresponding to the natural angular frequency, and / or, the frequency inertia coefficient and the damping coefficient satisfy a second constraint condition corresponding to the damping ratio. The first constraint includes: (9) in, The range of values ​​is ; The second constraint includes: (10) in, The value range of ζ is 0.6~0.8, which can ensure that the system has sufficient damping characteristics, avoid underdamped oscillations or even instability when ζ is too small, and avoid overdamping when ζ is too large, which would cause the dynamic response to be too slow and reduce the system's ability to track power disturbances.

[0067] in, H The frequency inertia coefficient, D The damping coefficient is... It is the natural angular frequency. These are the synchronization gain control parameters. This is the initial phase of the phase-locked loop. is the damping ratio. H The recommended value range is 1 to 5. This can avoid insufficient system inertia due to an excessively small value of H, which would lead to excessively drastic frequency dynamic response and excessive transient frequency deviation. At the same time, it can also avoid an excessively large value of H, which would result in an excessively slow system dynamic response, making it difficult to quickly track power changes and affecting the system's regulation performance.

[0068] In this embodiment, by combining the first constraint condition corresponding to the natural angular frequency and / or the second constraint condition corresponding to the damping ratio, the natural angular frequency characterizes the inherent oscillation frequency of the system in the undamped state, directly determining the small-signal closed-loop bandwidth and response speed of the self-synchronization loop. The damping ratio determines the rate of energy dissipation and the mode of oscillation decay of the system. The frequency inertia coefficient and damping coefficient are further optimized to achieve an optimal trade-off between the dynamic response speed, anti-disturbance capability and oscillation suppression capability of the system, thereby facilitating flexible configuration according to different grid strengths and application requirements.

[0069] To facilitate understanding of the technical advantages of the active frequency support synchronization control method for high-voltage DC converter valves provided in the above embodiments compared to the traditional PLL control method, please refer to the following: Figures 3-5 ,See Figures 3-5 The effects of the embodiments of this application were further verified through simulation.

[0070] Please see first. Figure 3 , Figure 3 This is a schematic diagram comparing the active frequency support synchronization control method for a high-voltage DC converter valve provided in one embodiment of this application with the traditional PLL control method; Figure 3 This is a graph showing the active power and output frequency response of the embodiment of this solution compared with that of a PLL. Figure 3 The upper part of the image (a) is set as scene 2. The power grid frequency dropped sharply by 1 second. Hz, 3.1 Under typical operating conditions of frequency recovery, frequency tracking lag under PLL control fails to provide effective frequency support. The proposed solution enables rapid frequency self-synchronization and increases active power injection in the early stages of frequency dips, demonstrating spontaneous synchronization capability and disturbance response consistent with dynamic changes in grid frequency. Figure 3 The lower half of Figure (b) further analyzes how this scheme achieves different dynamic support performances by adjusting the virtual inertia coefficient in the scenario of a 1Hz increase in grid frequency. The larger the inertia coefficient, the smoother the active power response and the longer the support duration, exhibiting typical inertial release characteristics; conversely, the smaller the inertia coefficient, the steeper the power response, verifying that the proposed method has the inertial regulation capability of a synchronous machine, and that controllable active power inertia support can be achieved through parameter setting.

[0071] Figure 4 This is a schematic diagram comparing the active frequency support synchronization control method for a high-voltage DC converter valve under extremely weak grid conditions provided in an embodiment of this application with the traditional PLL control method. Figure 4 Setting the scenario as an extremely weak network with SCR=1, this scheme enables the DC-side voltage to quickly establish and smoothly converge to 1.0. PU, steady-state fluctuation amplitude is less than 0.02 The PU (Power Transmission Line) method achieves a stable arc-extinguishing angle within the target range of 35° without significant jitter. The filtered AC current waveform is regular with neat peaks, and the harmonic content is below 3%, preventing secondary grid oscillations. In contrast, the traditional PLL method consistently exhibits a 0.8 ohm harmonic after initial setup. The violent oscillation of the PU makes it impossible to maintain stable operation. The arc extinction angle exhibits continuous fluctuations of more than ±10° throughout the entire simulation process, leading to a double increase in the risk of commutation failure and reactive power consumption. Its current amplitude and phase fluctuate synchronously with the DC voltage and the arc extinction angle oscillation, resulting in obvious asymmetry and distortion.

[0072] Figure 5 This is an active-frequency droop characteristic diagram of the active frequency support synchronization control method for a high-voltage DC converter valve provided in an embodiment of this application; its droop coefficient is equivalent to... The formula is: (11) in, The droop coefficient is... This refers to the per-unit value of phase A voltage in the three-phase voltage per-unit value of the power grid. D The damping coefficient is... These are the parameters for synchronous gain control.

[0073] Combination Figure 5 As shown, the vertical axis represents power (per unit, pu), and the horizontal axis represents frequency f (Hz), illustrating the droop relationship between the active power of the converter valve and the grid frequency under the self-synchronization control strategy in this embodiment. Figure 5 The solid blue line represents the ideal linear droop characteristic, indicating a linear relationship between the converter valve's active power output and frequency deviation; the dashed orange line represents the actual characteristic with saturation limiting. "Saturation (+1.0 pu)" and "Saturation (-1.0 pu)" are marked at ±1.0 pu, respectively, and "Sat@ 50.25Hz" at 50.25Hz indicates the positive saturation point, reflecting the actual operating boundary when the converter valve's capacity is limited; the dashed green line shows a gentler droop characteristic under another parameter configuration. Combined with... Figure 5As shown, unlike the traditional phase-locked loop (PLL) phase detection-tracking mechanism, the self-synchronization strategy directly couples the frequency deviation into a synchronization torque. When the grid frequency drops or rises sharply, the converter valve can spontaneously and instantaneously increase or decrease active power without additional outer loop Pf droop commands, providing the grid with primary frequency regulation support similar to that of a synchronous generator. By adjusting the damping coefficient and synchronization gain, this curve can be flexibly tuned: a steeper slope results in a strong response to small frequency deviations and greater support; a gentler slope provides a wider frequency locking range. This allows the converter valve to flexibly adapt to the strength of the grid at the connection point.

[0074] Compared to existing conventional DC converter valve synchronization calculations, this embodiment replaces the traditional phase-locked loop's dependence on ideal grid voltage with a virtual oscillator self-synchronization mechanism. This technology directly responds to the grid voltage waveform, autonomously generating a synchronization phase reference signal that is both synchronized with the grid and contains controllable dynamic characteristics. This enables stable synchronization in weak grid environments, significantly reducing the risk of commutation failure. Furthermore, by generating the phase through a nonlinear limit cycle equation, it possesses inherent amplitude stability and phase generation capability. By adjusting the coupling strength with the grid through synchronization gain parameters, it exhibits stronger robustness and smoother phase tracking performance compared to traditional phase-locked loops when grid voltage distortion, sags, or phase jumps occur.

[0075] Secondly, this embodiment integrates virtual inertia and droop characteristics into the synchronous control algorithm. Through an internal first-order frequency dynamic equation, it actively simulates the inertial response and damping characteristics of a synchronous generator, enabling the conventional DC system to possess rapid active power response capabilities to grid frequency change rates and frequency deviations. It also features adjustable virtual inertia and damping, filling the functional gaps in inertia support and primary frequency regulation. By setting frequency inertia parameters and damping coefficients, the DC system can simulate a synchronous generator when grid frequency disturbances occur, autonomously and rapidly adjusting its power exchange to provide active frequency support to the grid and suppress frequency oscillations.

[0076] Furthermore, this embodiment integrates synchronization and power regulation within a unified framework. It simplifies the design complexity of traditional multi-loop control by employing a dynamic synchronization control mechanism with adjustable inertia and damping characteristics, achieving faster and more direct dynamic response and enhancing the system's transient stability. In addition, this embodiment provides a design method that directly correlates performance indicators such as virtual inertia and damping coefficient with physical safety margins such as the converter's arc-extinguishing angle. Its core dynamic parameters are clearly defined and decoupled. By independently adjusting these synchronization gain control parameters, the frequency support strength and dynamic response speed required by a conventional DC system can be flexibly configured without changing the system's main circuit hardware, adapting to the grid connection requirements of different strengths and different grid operation specifications.

[0077] In summary, the active frequency support synchronization control method for the high-voltage DC converter valve in this application embodiment can ultimately achieve a synergistic improvement in active frequency support and stable operation capability in weak grids at low cost.

[0078] Based on the active frequency support synchronization control method for high-voltage DC converter valves provided in the above embodiments, and following the same conceptual framework, this application also provides an active frequency support synchronization control device for high-voltage DC converter valves, corresponding to the above-described active frequency support synchronization control method. The following describes... Figure 6 A detailed introduction is given to the active frequency support synchronization control device for high-voltage DC converter valves.

[0079] Figure 6 A schematic diagram of the active frequency support synchronization control device for a high-voltage DC converter valve provided in an embodiment of this application is shown. Figure 6 The active frequency support synchronization control device 600 for the high-voltage DC converter valve shown includes: The acquisition module 610 is used to acquire the three-phase voltage signal of the AC power grid connected to the high-voltage DC converter valve, and convert the three-phase voltage signal into orthogonal voltage components in a two-phase stationary coordinate system. The first calculation module 620 is used to calculate the error tracking term based on the virtual oscillator state variables of the orthogonal voltage components and the high-voltage DC converter valve; The second calculation module 630 is used to calculate the internal frequency state of the high voltage DC converter valve based on the error tracking term and in combination with at least one of the preset frequency inertia coefficient, damping coefficient and synchronous gain control parameters. The synchronous gain control parameters are used to adjust the convergence speed. The generation module 640 is used to calculate the synchronization phase reference signal based on the internal frequency state, and generate the valve control signal of the high voltage DC converter valve based on the synchronization phase reference signal.

[0080] This application provides an active frequency support synchronization control device for a high-voltage direct current (HVDC) converter valve. By setting corresponding functional modules, it acquires the three-phase voltage signal of the AC power grid connected to the HVDC converter valve and converts the three-phase voltage signal into orthogonal voltage components in a two-phase stationary coordinate system, thereby establishing a direct coupling relationship with the power grid voltage. Based on this, an error tracking term is calculated based on the orthogonal voltage components and the virtual oscillator state variables of the HVDC converter valve. This error tracking term reflects the real-time deviation between the power grid voltage and the internal oscillation state, providing a basis for subsequent dynamic frequency adjustment. Next, based on the error tracking term, and combined with at least one of the preset frequency inertia coefficient, damping coefficient, and synchronization gain control parameters used to adjust the convergence speed, the internal frequency state of the HVDC converter valve is calculated. This allows the internal frequency state to adaptively adjust according to power grid frequency disturbances, simulating the rotor motion characteristics of a synchronous generator. Subsequently, a synchronization phase reference signal is calculated based on the internal frequency state, and a valve control signal for the HVDC converter valve is generated based on the synchronization phase reference signal. This triggers phase adjustment to achieve dynamic frequency adjustment, realizing the physical coupling of power response and frequency change.

[0081] As described above, the embodiments of this application replace the passive tracking of the external voltage phase by the traditional phase-locked loop by dynamically synchronizing the synchronization phase reference signal with the power grid. This technology directly responds to the power grid voltage waveform and autonomously generates a synchronization phase reference signal that is both synchronized with the power grid and contains controllable dynamic characteristics (frequency inertia coefficient, damping coefficient, and synchronization gain control parameters for adjusting convergence speed). This improves synchronization robustness under non-ideal voltage conditions and reduces the risk of commutation failure due to synchronization errors. Simultaneously, by mapping power grid frequency disturbances to changes in internal frequency states, the valve control signal is directly adjusted, enabling the DC converter valve to have a rapid active power support response capability to frequency deviations and rates of change, achieving the inertia support and damping regulation functions of a synchronous machine. Compared to existing technologies, the active frequency support synchronization control device for a high-voltage DC converter valve in this application embodiment can achieve the above functions by replacing the polarity control synchronization loop without adding additional hardware. It can solve the technical problems of conventional DC converter valves being unable to operate stably in weak grid environments and receiving-end converter valves lacking frequency support capabilities at low cost, effectively improving the safe and stable operation level of renewable energy grids, and achieving active frequency support and improved stable operation capability in weak grids at low cost.

[0082] In some possible implementations, after calculating the internal frequency state of the high-voltage DC converter valve, the active frequency support synchronization control device for the high-voltage DC converter valve further includes: The update module is used to update the virtual oscillator state variables based on the internal frequency state and the virtual oscillator state variables, and... The return module is used to return to the steps of calculating the error tracking term based on the virtual oscillator state variables of the high-voltage DC converter valve and the orthogonal voltage components, in order to update the internal frequency state of the high-voltage DC converter valve.

[0083] In some possible implementations, the virtual oscillator state variables are updated based on the internal frequency state and the virtual oscillator state variables, including: The virtual oscillator state variables are updated based on the nonlinear limit cycle oscillator equation, according to the internal frequency state and the virtual oscillator state variables. The equations for the nonlinear limit ring oscillator include:

[0084] in, , For virtual oscillator state variables, A For the amplitude of the virtual oscillator, This refers to the internal frequency state.

[0085] In some possible implementations, the error tracking term is calculated based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, including: Based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, the error tracking term is calculated using a preset error calculation formula; the error calculation formula includes:

[0086] in, , For virtual oscillator state variables, , These are orthogonal voltage components. This is the error tracking term.

[0087] In some possible implementations, the second calculation module, based on the error tracking term and in conjunction with at least one of the preset frequency inertia coefficient, damping coefficient, and synchronous gain control parameters, calculates the internal frequency state of the high-voltage DC converter valve, including: The calculation submodule is used to calculate the differential value of the internal frequency state based on the error tracking term, combined with at least one of the frequency inertia coefficient, damping coefficient and synchronization gain control parameters. The determination submodule is used to determine the internal frequency state based on the differential value of the internal frequency state.

[0088] In some possible implementations, the differential value of the internal frequency state is calculated based on the error tracking term, combined with at least one of the frequency inertia coefficient, damping coefficient, and synchronization gain control parameters, including: Based on the error tracking term, and combined with the frequency inertia coefficient, damping coefficient, and synchronization gain control parameters, the differential value of the internal frequency state is calculated through a preset first-order frequency dynamic equation; the first-order frequency dynamic equation includes:

[0089] in, For error tracking, H The frequency inertia coefficient, D The damping coefficient is... For reference, the rated frequency, These are the synchronization gain control parameters. This refers to the internal frequency state.

[0090] In some possible implementations, the frequency inertia coefficient satisfies a first constraint relationship, the damping coefficient satisfies a second constraint relationship, and / or, the synchronization gain control parameter satisfies a third constraint relationship; The first constraint relationship includes: The second constraint relationship includes: The third constraint relationship includes: in, H The frequency inertia coefficient, D The damping coefficient is... These are the synchronization gain control parameters. This is the design value for the maximum frequency error; This represents the maximum rate of change of the power grid frequency. The phase angle difference at the steady-state operating point or the maximum permissible linearized phase shift; It is the maximum permissible dynamic phase margin; It is the synchronous stiffness coefficient. This represents the minimum voltage amplitude of the power grid.

[0091] In some possible implementations, the frequency inertia coefficient and the damping coefficient satisfy a first constraint condition corresponding to the natural angular frequency, and / or, the frequency inertia coefficient and the damping coefficient satisfy a second constraint condition corresponding to the damping ratio. The first constraint includes: , The range of values ​​is ; The second constraint includes: , The value range is 0.6 to 0.8; in, H The frequency inertia coefficient, D The damping coefficient is... It is the natural angular frequency. These are the synchronization gain control parameters. This is the initial phase of the phase-locked loop. is the damping ratio.

[0092] Based on the active frequency support synchronization control method for high-voltage DC converter valves provided in the above embodiments, and with the same inventive concept, this application also provides an active frequency support synchronization control device for high-voltage DC converter valves, corresponding to the above-mentioned active frequency support synchronization control method for high-voltage DC converter valves. The following describes... Figure 7 This paper provides a detailed introduction to the active frequency support synchronization control equipment for high-voltage DC converter valves.

[0093] Please see below. Figure 7 , Figure 7 This is a schematic diagram of the active frequency support synchronization control device for a high-voltage DC converter valve provided in one embodiment of this application.

[0094] The active frequency support synchronization control device for the high voltage DC converter valve may include a processor 701 and a memory 702 storing computer program instructions.

[0095] Specifically, the processor 701 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0096] Memory 702 may include mass storage for data or instructions. For example, and not limitingly, memory 702 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 702 may include removable or non-removable (or fixed) media. Where appropriate, memory 702 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, memory 702 is non-volatile solid-state memory.

[0097] Memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the methods according to one aspect of this disclosure.

[0098] The processor 701 reads and executes computer program instructions stored in the memory 702 to implement any of the active frequency support synchronization control methods for high voltage DC converter valves in the above embodiments.

[0099] In one example, the active frequency support synchronization control device for the data high-voltage DC converter valve may further include a communication interface 703 and a bus 710. Wherein, as Figure 7 As shown, the processor 701, memory 702, and communication interface 703 are connected through bus 710 and complete communication with each other.

[0100] The communication interface 703 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0101] Bus 710 includes hardware, software, or both, that couples together components of the active frequency support synchronization control device for the high-voltage DC converter valve. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 710 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, any suitable bus or interconnect is contemplated herein.

[0102] The active frequency support synchronization control device of the high voltage DC converter valve executes the active frequency support synchronization control method of the high voltage DC converter valve in the embodiments of this application, thereby realizing the active frequency support synchronization control method of the high voltage DC converter valve described in the embodiments of this application.

[0103] Furthermore, in conjunction with the active frequency support synchronization control method for the high-voltage DC converter valve in the above embodiments, this application embodiment can provide a computer storage medium for implementation. This computer storage medium stores computer program instructions; when these computer program instructions are executed by a processor, they implement any of the active frequency support synchronization control methods for the high-voltage DC converter valve in the above embodiments.

[0104] Based on the active frequency support synchronization control method for high-voltage DC converter valves in the above embodiments, this application provides a computer program product. When the instructions in the computer program product are executed by the processor of an electronic device, the electronic device executes the active frequency support synchronization control method for high-voltage DC converter valves provided in any of the above embodiments of this application.

[0105] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0106] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0107] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0108] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in 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, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0109] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A method of active frequency support synchronization control of a high voltage direct current converter valve, characterized in that, include: The three-phase voltage signal of the AC power grid connected to the high-voltage DC converter valve is obtained, and the three-phase voltage signal is converted into orthogonal voltage components in a two-phase stationary coordinate system. Based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, the error tracking term is calculated; Based on the error tracking term, and combined with at least one of the preset frequency inertia coefficient, damping coefficient and synchronous gain control parameter, the internal frequency state of the high voltage DC converter valve is calculated. The synchronous gain control parameter is used to adjust the convergence speed. The synchronization phase reference signal is calculated based on the internal frequency state, and the valve control signal of the high-voltage DC converter valve is generated based on the synchronization phase reference signal.

2. The method of claim 1, wherein, After calculating the internal frequency state of the high-voltage DC converter valve, the method further includes: Update the virtual oscillator state variables based on the internal frequency state and the virtual oscillator state variables, and... Returning to the step of calculating the error tracking term based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, in order to update the internal frequency state of the high-voltage DC converter valve.

3. The method according to claim 1, characterized in that, The step of updating the virtual oscillator state variables based on the internal frequency state and the virtual oscillator state variables includes: The virtual oscillator state variables are updated based on the nonlinear limit ring oscillator equation according to the internal frequency state and the virtual oscillator state variables. The nonlinear limit ring oscillator equations include: ， in, , For the virtual oscillator state variables, A For the amplitude of the virtual oscillator, This refers to the internal frequency state.

4. The method according to claim 1, characterized in that, The calculation of the error tracking term based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve includes: Based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve, the error tracking term is calculated using a preset error calculation formula; the error calculation formula includes: ， in, , For the virtual oscillator state variables, , These are the orthogonal voltage components. This refers to the error tracking term.

5. The method according to claim 1, characterized in that, The calculation of the internal frequency state of the high-voltage DC converter valve based on the error tracking term, combined with at least one of the preset frequency inertia coefficient, damping coefficient, and synchronous gain control parameters, includes: Based on the error tracking term, and in combination with at least one of the frequency inertia coefficient, the damping coefficient, and the synchronization gain control parameter, the differential value of the internal frequency state is calculated. The internal frequency state is determined based on the differential value of the internal frequency state.

6. The method according to claim 5, characterized in that, The step of calculating the differential value of the internal frequency state based on the error tracking term, combined with at least one of the frequency inertia coefficient, the damping coefficient, and the synchronization gain control parameter, includes: Based on the error tracking term, and in conjunction with the frequency inertia coefficient, the damping coefficient, and the synchronization gain control parameters, the differential value of the internal frequency state is calculated using a preset first-order frequency dynamic equation; the first-order frequency dynamic equation includes: ， in, For the error tracking term, H The frequency inertia coefficient, D The damping coefficient is... For reference, the rated frequency, These are the synchronization gain control parameters. This refers to the internal frequency state.

7. The method according to claim 1, characterized in that, The frequency inertia coefficient satisfies the first constraint relationship, the damping coefficient satisfies the second constraint relationship, and / or the synchronization gain control parameter satisfies the third constraint relationship; The first constraint relationship includes: , The second constraint relationship includes: , The third constraint relation includes: , in, H The frequency inertia coefficient, D The damping coefficient is... These are the synchronization gain control parameters. This is the design value for the maximum frequency error; This represents the maximum rate of change of the power grid frequency. The phase angle difference at the steady-state operating point or the maximum permissible linearized phase shift; It is the maximum permissible dynamic phase margin; It is the synchronous stiffness coefficient. This represents the minimum voltage amplitude of the power grid.

8. The method according to claim 1, characterized in that, The frequency inertia coefficient and the damping coefficient satisfy the first constraint condition corresponding to the natural angular frequency, and / or the frequency inertia coefficient and the damping coefficient satisfy the second constraint condition corresponding to the damping ratio. The first constraint includes: , The range of values ​​is ; The second constraint includes: , The value range is 0.6 to 0.8; in, H The frequency inertia coefficient, D The damping coefficient is... The natural angular frequency, These are the synchronization gain control parameters. This is the initial phase of the phase-locked loop. The damping ratio is given.

9. An active frequency support synchronization control device for a high-voltage DC converter valve, characterized in that, The device includes: The acquisition module is used to acquire the three-phase voltage signal of the AC power grid connected to the high-voltage DC converter valve, and convert the three-phase voltage signal into orthogonal voltage components in a two-phase stationary coordinate system. The first calculation module is used to calculate the error tracking term based on the orthogonal voltage components and the virtual oscillator state variables of the high-voltage DC converter valve; The second calculation module is used to calculate the internal frequency state of the high voltage DC converter valve based on the error tracking term and in combination with at least one of the preset frequency inertia coefficient, damping coefficient and synchronous gain control parameter. The synchronous gain control parameter is used to adjust the convergence speed. The generation module is used to calculate the synchronization phase reference signal based on the internal frequency state, and generate the valve control signal of the high voltage DC converter valve based on the synchronization phase reference signal.

10. An active frequency support synchronization control device for a high-voltage DC converter valve, characterized in that, The device includes: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, it implements the active frequency support synchronization control method for the high-voltage DC converter valve as described in any one of claims 1-8.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer program instructions, which, when executed by a processor, implement the active frequency support synchronization control method for a high-voltage DC converter valve as described in any one of claims 1-8.

12. A computer program product, characterized in that, When the instructions in the computer program product are executed by the processor of the electronic device, the electronic device performs the active frequency support synchronization control method for the high-voltage DC converter valve as described in any one of claims 1-8.

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