A damping control method, system, medium and device for a grid-type flexible DC converter

Abstract

The present invention discloses a damping control method, system, medium, and equipment for a grid-type flexible DC converter, belonging to the field of stability control of high-voltage direct current transmission systems. The method comprises: generating a normalized power deviation based on a reference value and output value of the active power of the grid-type flexible DC converter and the rated angular frequency of the grid-connected system; performing deviation superposition processing on the normalized power deviation based on the damping compensation power deviation to obtain a first power deviation, and integrating the first power deviation based on the inertia coefficient to obtain an angular frequency deviation; wherein, after each angular frequency deviation is generated, the damping compensation power deviation is updated; and voltage reference data is generated based on the angular frequency deviation and the output voltage amplitude of the virtual synchronous machine, and a pulse width modulation signal is further generated to control the grid-type flexible DC converter. Therefore, by implementing the present invention, the problem that the traditional strategy of the virtual synchronous machine in the prior art is difficult to achieve high stability and high-precision power control at the same time can be solved.

Description

Technical Field

[0001] The present invention belongs to the field of stability control of high-voltage direct current transmission systems, and relates to a damping control method, system, medium and equipment for a grid-type flexible direct current converter. Background Art

[0002] Flexible DC transmission systems, due to their flexible active and reactive power regulation capabilities, have become a key solution for large-scale renewable energy integration and regional grid interconnection. Traditional flexible DC transmission systems employ a phase-locked loop (PLL)-based vector control strategy, achieving power control by sampling the grid voltage phase. However, under extremely weak operating conditions with reduced grid strength, the PLL struggles to accurately track the grid voltage phase, which can easily lead to instability in response to small disturbances. To address this, grid-based control methods (such as droop control and virtual synchronous generator control) have been proposed to enhance system support capabilities in weak grids. Virtual synchronous generator control simulates the inertia and damping characteristics of synchronous generators, providing the system with inertial response and dynamic damping. It is widely used in weak grid access and renewable energy grid connection scenarios.

[0003] However, in traditional virtual synchronous machine control strategies, the selection of the damping coefficient must balance system stability and power output accuracy. When the system is in constant power control mode, if the damping coefficient is set high to ensure stability, the output power of the flexible DC converter will deviate from the command value during normal grid frequency fluctuations, and the steady-state power deviation may exceed the 1% limit required by national standards. Conversely, if the damping coefficient is reduced to prioritize power accuracy, the risk of system oscillation may arise. This contradiction makes it difficult for traditional methods to achieve both high stability and high-precision power control under weak grid conditions, limiting the engineering application of grid-type converters. Summary of the Invention

[0004] The present application provides a damping control method, system, medium and equipment for a grid-type flexible DC converter, which can solve the problem in the prior art that the traditional strategy of virtual synchronous machine is difficult to achieve high stability and high-precision power control at the same time.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a damping control method for a grid-type flexible DC converter, comprising:

[0006] Generate a normalized power deviation based on the active power reference value of the grid-connected flexible DC converter, the current output value, and the rated angular frequency of the grid-connected system;

[0007] A deviation superposition process is performed on the preset damping compensation power deviation and the normalized power deviation to obtain a first power deviation, and an integral operation is performed on the first power deviation according to a preset inertia coefficient to obtain an angular frequency deviation; wherein, after each angular frequency deviation is generated, the damping compensation power deviation is updated according to the angular frequency deviation and a preset angular frequency deviation compensation amount; and after each update of the damping compensation power deviation, the angular frequency deviation compensation amount is updated according to the first power deviation and the updated damping compensation power deviation.

[0008] generating voltage reference data according to the angular frequency deviation and the output voltage amplitude of the virtual synchronous machine;

[0009] A pulse width modulation signal is generated according to the voltage reference data, and the grid-type flexible direct current converter is controlled according to the pulse width modulation signal.

[0010] Compared with the prior art, the embodiments of the present application have the following beneficial effects: by generating a normalized power deviation based on the active power reference value of the grid-type flexible DC converter, the current output value and the rated angular frequency of the grid-connected system, the power deviation is converted into a frequency-related per-unit value to adapt to the dimensional unification requirements of the subsequent control link; by superimposing the preset damping compensation power deviation and the normalized power deviation, a closed-loop feedback mechanism is formed to enhance the transient response speed; the first power deviation is integrated by a preset inertia coefficient to simulate the mechanical inertia characteristics of the synchronous generator and suppress the power oscillation caused by the sudden change of the grid frequency; by The preset angular frequency deviation compensation dynamically updates the damping compensation power deviation, and adjusts the damping compensation in real time to optimize the transient damping performance. By updating the angular frequency deviation compensation based on the first power deviation and the updated damping compensation power deviation, the steady-state power deviation is eliminated through combined integral compensation to improve control accuracy. By integrating the angular frequency deviation with the output voltage amplitude, voltage reference data adapted to the current working conditions is generated to ensure real-time matching of the power command with the system state. The voltage reference data is converted into a pulse width modulation signal, and the converter output is dynamically adjusted based on the modulation signal to ensure rapid tracking of active power and grid frequency, thereby improving transient response speed and steady-state execution efficiency. Through the synergistic combination design of the above-mentioned features, this solution constructs local negative feedback within the damping link, avoids direct feedback of the angular frequency deviation, improves steady-state power control accuracy and transient damping enhancement, and resolves the contradiction between stability and accuracy in traditional virtual synchronous machine control.

[0011] In some embodiments of the first aspect of the present application, generating a normalized power deviation based on a reference value of the active power of the grid-connected flexible DC converter, a current output value, and a rated angular frequency of the grid-connected system includes:

[0012] Performing deviation calculation on the reference value and current output value of the active power of the grid-type flexible DC converter to obtain the original power deviation;

[0013] The original power deviation is normalized according to the rated angular frequency of the grid-connected system to obtain a normalized power deviation.

[0014] Compared with the existing technology, the above embodiment has the following beneficial effects: by performing deviation calculation on the active power reference value and the current output value of the grid-connected flexible DC converter to obtain the original power deviation, the instantaneous error signal between the power instruction and the actual output is directly extracted to provide a basic input for closed-loop control; by normalizing the original power deviation based on the rated angular frequency of the grid-connected system, the dimensional difference under different grid frequency scenarios is eliminated, thereby improving the cross-operating condition versatility of the control strategy.

[0015] In some embodiments of the first aspect of the present application, the damping compensation power deviation is updated according to the angular frequency deviation and a preset angular frequency deviation compensation amount each time the angular frequency deviation is generated, including:

[0016] After each angular frequency deviation is generated, a damping proportional operation is performed on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine to obtain an updated damping compensation power deviation; wherein the formula for the damping proportional operation is:

[0017] ;in, represents the damping compensation power deviation, D represents the damping coefficient, represents the angular frequency deviation, Indicates the angular frequency deviation compensation amount.

[0018] Compared with the prior art, the above embodiment has the following beneficial effects: after each angular frequency deviation is generated, a damping proportional operation is performed on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine, the damping coefficient is used to quantify the dynamic deviation weight, and the damping compensation power deviation is quickly adjusted to suppress transient power fluctuations.

[0019] In some embodiments of the first aspect of the present application, the angular frequency deviation compensation amount is updated according to the first power deviation and the updated damping compensation power deviation after each update of the damping compensation power deviation, including:

[0020] After each update of the damping compensation power deviation, a joint integral compensation operation is performed according to the preset adjustment coefficient, the first power deviation and the updated damping compensation power deviation to obtain an updated angular frequency deviation compensation amount;

[0021] The formula for the joint integral compensation operation is:

[0022] ; Where K represents the adjustment coefficient, s represents the Laplace operator, Indicates the first power deviation.

[0023] Compared with the prior art, the above embodiment has the following beneficial effects: by performing a joint integral compensation operation based on the preset adjustment coefficient, the first power deviation and the updated damping compensation power deviation after each update of the damping compensation power deviation, the steady-state error is gradually eliminated through the integral action, ensuring that the power output strictly tracks the command value; by jointly adjusting the forward power deviation and the feedback compensation amount, a dynamic compensation mechanism is formed, thereby enhancing the system's adaptive correction capability for long-term deviations.

[0024] In some embodiments of the first aspect of the present application, generating voltage reference data according to the angular frequency deviation and the output voltage amplitude of the virtual synchronous machine includes:

[0025] Performing a phase synthesis integration operation on the angular frequency deviation and the rated angular frequency to generate an output phase of the virtual synchronous machine;

[0026] Polar coordinate transformation is performed according to the output voltage amplitude and the output phase of the virtual synchronous machine to generate a first voltage reference value and a second voltage reference value as voltage reference data.

[0027] Compared with the existing technology, the above embodiment has the following beneficial effects: by synthesizing the dynamic angular frequency deviation with the rated angular frequency and integrating them, a continuous phase signal synchronized with the power grid is generated, ensuring that the output phase of the virtual synchronous machine dynamically matches the grid reference frequency, thereby improving the synchronization stability under weak power grids; the integral operation smoothes the sudden change of angular frequency and suppresses the power oscillation caused by transient phase jumps. The output voltage amplitude and phase in the polar coordinate system are converted to the voltage reference value in the stationary coordinate system to adapt to the requirements of the converter modulation algorithm and realize the precise mapping of power control instructions to voltage waveforms; the polar coordinate transformation retains the orthogonal characteristics of amplitude and phase through trigonometric function operations, ensuring the amplitude consistency and phase continuity of the voltage reference value, thereby improving the quality of the converter output waveform and the dynamic tracking accuracy.

[0028] In a second aspect, the present invention further provides a grid-type flexible DC converter damping control system, comprising: a normalized power deviation calculation module, an angular frequency deviation calculation module, a voltage data generation module, and a signal control module;

[0029] The normalized power deviation calculation module is configured to generate a normalized power deviation based on a reference value of the active power of the grid-connected flexible DC converter, a current output value, and a rated angular frequency of the grid-connected system;

[0030] The angular frequency deviation calculation module is configured to perform deviation superposition processing based on a preset damping compensation power deviation and the normalized power deviation to obtain a first power deviation, and perform an integration operation on the first power deviation based on a preset inertia coefficient to obtain an angular frequency deviation; wherein, after each angular frequency deviation is generated, the damping compensation power deviation is updated based on the angular frequency deviation and a preset angular frequency deviation compensation amount; and after each update of the damping compensation power deviation, the angular frequency deviation compensation amount is updated based on the first power deviation and the updated damping compensation power deviation.

[0031] The voltage data generating module is configured to generate voltage reference data according to the angular frequency deviation and the output voltage amplitude of the virtual synchronous machine;

[0032] The signal control module is used to generate a pulse width modulation signal according to the voltage reference data, and control the grid-type flexible direct current converter according to the pulse width modulation signal.

[0033] Compared with the prior art, the above embodiments of the present application have the following beneficial effects: by generating a normalized power deviation based on the active power reference value of the grid-type flexible DC converter, the current output value and the rated angular frequency of the grid-connected system, the power deviation is converted into a frequency-related per-unit value to adapt to the dimensional unification requirements of the subsequent control link; by superimposing the preset damping compensation power deviation and the normalized power deviation, a closed-loop feedback mechanism is formed to enhance the transient response speed; the first power deviation is integrated by a preset inertia coefficient to simulate the mechanical inertia characteristics of the synchronous generator and suppress the power oscillation caused by the sudden change of the grid frequency; by Dynamically update the damping compensation power deviation with the preset angular frequency deviation compensation, and adjust the damping compensation in real time to optimize the transient damping performance; update the angular frequency deviation compensation based on the first power deviation and the updated damping compensation power deviation, and eliminate the steady-state power deviation through joint integral compensation to improve control accuracy; generate voltage reference data adapted to the current working conditions by integrating the angular frequency deviation with the output voltage amplitude, ensuring real-time matching of the power instruction with the system state; convert the voltage reference data into a pulse width modulation signal, and dynamically adjust the converter output based on the modulation signal to ensure rapid tracking of active power and grid frequency, thereby improving transient response speed and steady-state execution efficiency. This solution, through the synergistic combination design of the above-mentioned features, constructs local negative feedback within the damping link, avoids direct feedback of the angular frequency deviation, improves steady-state power control accuracy and transient damping enhancement, and resolves the contradiction between stability and accuracy in traditional virtual synchronous machine control.

[0034] In some embodiments of the second aspect of the present application, the normalized power deviation calculation module includes: an original power deviation calculation unit and a normalization processing unit;

[0035] The original power deviation calculation unit is used to perform deviation calculation on the reference value and current output value of the active power of the grid-type flexible DC converter to obtain the original power deviation;

[0036] The normalization processing unit is used to perform normalization processing on the original power deviation according to the rated angular frequency of the grid-connected system to obtain a normalized power deviation.

[0037] Compared with the existing technology, the above embodiment has the following beneficial effects: by performing deviation calculation on the active power reference value and the current output value of the grid-connected flexible DC converter to obtain the original power deviation, the instantaneous error signal between the power instruction and the actual output is directly extracted to provide a basic input for closed-loop control; by normalizing the original power deviation based on the rated angular frequency of the grid-connected system, the dimensional difference under different grid frequency scenarios is eliminated, thereby improving the cross-operating condition versatility of the control strategy.

[0038] In some embodiments of the second aspect of the present application, the angular frequency deviation calculation module includes: a first updating unit;

[0039] The first updating unit is configured to perform a damping proportional operation on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine each time the angular frequency deviation is generated, to obtain an updated damping compensation power deviation; wherein the damping proportional operation is calculated as follows:

[0040] ;in, represents the damping compensation power deviation, D represents the damping coefficient, represents the angular frequency deviation, Indicates the angular frequency deviation compensation amount.

[0041] Compared with the prior art, the above embodiment has the following beneficial effects: after each angular frequency deviation is generated, a damping proportional operation is performed on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine, the damping coefficient is used to quantify the dynamic deviation weight, and the damping compensation power deviation is quickly adjusted to suppress transient power fluctuations.

[0042] In a third aspect, the present invention also provides a grid-type flexible DC converter damping control device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when loaded into the processor, implements any one of the steps of a grid-type flexible DC converter damping control method.

[0043] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of any one of the methods for controlling damping of a grid-type flexible direct current converter are implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 : A flow chart of a damping control method for a grid-type flexible DC converter provided in some embodiments of the present invention.

[0045] Figure 2 : A structural schematic diagram of a grid-type flexible DC converter damping control system provided in some embodiments of the present invention.

[0046] Figure 3 : A structural diagram of a grid-type flexible DC converter damping control device provided in some embodiments of the present invention.

[0047] Figure 4 : A control diagram of a typical virtual synchronous machine provided in some embodiments of the present invention.

[0048] Figure 5 : A control schematic diagram of a virtual synchronous machine that implements an optimized damping strategy provided in some embodiments of the present invention.

[0049] Figure 6 : A comparison diagram of response curves of a power grid frequency step provided in some embodiments of the present invention. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] Example 1:

[0052] Please refer to Figure 1 To solve the problem in the prior art that the traditional strategy of virtual synchronous machines is difficult to achieve both high stability and high-precision power control, an embodiment of the present invention provides a damping control method for a grid-type flexible DC converter, comprising steps S1 to S4:

[0053] Step S1: Generate a normalized power deviation based on the reference value of the active power of the grid-connected flexible DC converter, the current output value and the rated angular frequency of the grid-connected system.

[0054] Furthermore, step S1 can be implemented by the following preferred implementation, including steps S11-S12, as follows:

[0055] S11: performing a deviation operation on the reference value of the active power of the grid-forming flexible DC converter and the current output value to obtain an original power deviation.

[0056] S12: Normalizing the original power deviation according to the rated angular frequency of the grid-connected system to obtain a normalized power deviation.

[0057] In a specific implementation, the original power deviation in step S11 and the normalized power deviation in step S12 can be calculated using the following formula:

[0058] ;in represents the original power deviation, Indicates the reference value of active power of grid-connected flexible DC converter. Indicates the output value of active power of the grid-connected flexible DC converter.

[0059] ;in, represents the normalized power deviation, Indicates the rated angular frequency of the grid-connected system.

[0060] In this preferred embodiment, steps S11-S12 obtain the original power deviation by performing deviation calculation on the active power reference value and the current output value of the grid-connected flexible DC converter, directly extract the instantaneous error signal between the power command and the actual output, and provide a basic input for closed-loop control; by normalizing the original power deviation based on the rated angular frequency of the grid-connected system, the dimensional difference under different grid frequency scenarios is eliminated, thereby improving the cross-operating-condition versatility of the control strategy.

[0061] Step S2: According to the preset damping compensation power deviation and the normalized power deviation, deviation superposition processing is performed to obtain a first power deviation, and according to the preset inertia coefficient, the first power deviation is integrated to obtain an angular frequency deviation; wherein, after each angular frequency deviation is generated, the damping compensation power deviation is updated according to the angular frequency deviation and the preset angular frequency deviation compensation amount; after each update of the damping compensation power deviation, the angular frequency deviation compensation amount is updated according to the first power deviation and the updated damping compensation power deviation.

[0062] In specific implementation, the first power deviation in step S2 can be obtained by the following calculation:

[0063] ;in, represents the first power deviation, Represents the damping-compensated power deviation. Specifically, when the first power deviation of the current control cycle needs to be calculated, the damping-compensated power deviation updated in the previous cycle can be used. The damping-compensated power deviation updated in the current cycle can be used in the next cycle, and so on. The specific update method of the damping-compensated power deviation can be referred to in step S21 below.

[0064] Additionally, the angular frequency deviation is calculated as follows:

[0065] ;in represents the angular frequency deviation, J represents the inertia coefficient, and s represents the Laplace operator.

[0066] Furthermore, in step S2, the updating of the damping compensation power deviation can be achieved by the following preferred implementation, including step S21, specifically as follows:

[0067] S21: After each angular frequency deviation is generated, a damping proportional operation is performed on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine to obtain an updated damping compensation power deviation; wherein the damping proportional operation formula is:

[0068] ;in, represents the damping compensation power deviation, D represents the damping coefficient, represents the angular frequency deviation, Indicates the angular frequency deviation compensation amount.

[0069] Similarly, like the damping compensation power deviation, after the damping compensation power deviation is updated, the angular frequency deviation compensation amount also needs to be updated. For details, please refer to the following step S22.

[0070] In this preferred embodiment, step S21 performs a damping proportional operation on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine after each angular frequency deviation is generated, quantifies the dynamic deviation weight using the damping coefficient, and quickly adjusts the damping compensation power deviation to suppress transient power fluctuations.

[0071] Furthermore, in step S2, the updating of the angular frequency deviation compensation amount can be achieved by the following preferred implementation, including step S22, specifically as follows:

[0072] S22: After each update of the damping compensation power deviation, performing a joint integral compensation operation according to the preset adjustment coefficient, the first power deviation, and the updated damping compensation power deviation to obtain an updated angular frequency deviation compensation amount;

[0073] The formula for the joint integral compensation operation is:

[0074] ; Where K represents the adjustment coefficient, s represents the Laplace operator, Indicates the first power deviation.

[0075] In this preferred embodiment, step S22 performs a joint integral compensation operation based on the preset adjustment coefficient, the first power deviation and the updated damping compensation power deviation after each update of the damping compensation power deviation, gradually eliminating the steady-state error through the integral action to ensure that the power output strictly tracks the command value; by jointly adjusting the forward power deviation and the feedback compensation amount, a dynamic compensation mechanism is formed to enhance the system's adaptive correction capability for long-term deviations.

[0076] Step S3: generating voltage reference data according to the angular frequency deviation and the output voltage amplitude of the virtual synchronous machine.

[0077] Furthermore, step S3 can be implemented by the following preferred implementation, including steps S31-S32, as follows:

[0078] S31: performing a phase synthesis integration operation on the angular frequency deviation and the rated angular frequency to generate an output phase of the virtual synchronous machine.

[0079] In specific implementation, the output phase can be calculated using the following formula:

[0080] ;in Indicates the output phase.

[0081] S32: Perform polar coordinate transformation processing according to the output voltage amplitude and the output phase of the virtual synchronous machine to generate a first voltage reference value and a second voltage reference value as voltage reference data.

[0082] In a specific implementation, the calculation formulas of the first voltage reference value and the second voltage reference value are as follows:

[0083] ; ;in, and Respectively represent stillness Voltage reference value on the coordinate system component (ie, the first voltage reference value) and the voltage reference value Component (ie, the second voltage reference value), U represents the output voltage amplitude of the virtual synchronous machine obtained based on the reactive power control of the virtual synchronous machine.

[0084] In this preferred embodiment, steps S31-S32 generate a continuous phase signal synchronized with the grid by synthesizing the dynamic angular frequency deviation and the rated angular frequency and integrating them. This ensures that the output phase of the virtual synchronous machine dynamically matches the grid reference frequency, thereby improving synchronization stability in weak grid conditions. The integral operation smoothes sudden angular frequency changes and suppresses power oscillations caused by transient phase jumps. The output voltage amplitude and phase in the polar coordinate system are converted to voltage reference values ​​in the stationary coordinate system to adapt to the requirements of the converter modulation algorithm and achieve precise mapping of power control commands to voltage waveforms. The polar coordinate transformation preserves the orthogonality of amplitude and phase through trigonometric function operations, ensuring amplitude consistency and phase continuity of the voltage reference value, thereby improving the quality of the converter output waveform and dynamic tracking accuracy.

[0085] Step S4: Generate a pulse width modulation signal according to the voltage reference data, and control the grid-type flexible DC converter according to the pulse width modulation signal.

[0086] In specific implementation, the voltage reference data can be and The input voltage and current dual closed-loop control system outputs a PWM signal (i.e., a pulse width modulation signal) to achieve control of the grid-type flexible DC converter.

[0087] In this embodiment, step S4 converts the voltage reference data into a pulse width modulation signal, and dynamically adjusts the converter output based on the modulation signal to ensure fast tracking of active power and grid frequency, thereby improving transient response speed and steady-state execution efficiency.

[0088] In summary, compared with the prior art, the above embodiments of the present application have the following beneficial effects: by generating a normalized power deviation based on the active power reference value of the grid-type flexible DC converter, the current output value and the rated angular frequency of the grid-connected system, the power deviation is converted into a frequency-related per-unit value to adapt to the dimensional unification requirements of the subsequent control link; by superimposing the preset damping compensation power deviation and the normalized power deviation, a closed-loop feedback mechanism is formed to enhance the transient response speed; the first power deviation is integrated by a preset inertia coefficient to simulate the mechanical inertia characteristics of the synchronous generator and suppress the power oscillation caused by the sudden change of the grid frequency; by The damping compensation power deviation is dynamically updated based on the deviation and the preset angular frequency deviation compensation, and the damping compensation is adjusted in real time to optimize the transient damping performance; by updating the angular frequency deviation compensation based on the first power deviation and the updated damping compensation power deviation, the steady-state power deviation is eliminated by combined integral compensation to improve the control accuracy; by integrating the angular frequency deviation and the output voltage amplitude, voltage reference data adapted to the current working conditions is generated to ensure real-time matching of the power command and the system state; the voltage reference data is converted into a pulse width modulation signal, and the converter output is dynamically adjusted based on the modulation signal to ensure rapid tracking of active power and grid frequency, thereby improving transient response speed and steady-state execution efficiency. Through the synergistic combination design of the above-mentioned features, this solution constructs local negative feedback within the damping link, avoids direct feedback of the angular frequency deviation, improves the steady-state power control accuracy and transient damping enhancement, and solves the contradiction between stability and accuracy in traditional virtual synchronous machine control.

[0089] refer to Figure 4 A typical control diagram of a virtual synchronous machine is shown in FIG. Figure 5 A control diagram of a virtual synchronous machine that executes an optimized damping strategy (i.e., this solution) is shown as follows: Figure 6 The following figure shows a comparison of the response curves for a grid frequency step. To verify the effectiveness of the proposed method, a comparative simulation study was conducted with a typical virtual synchronous machine. The active power reference value of the grid-forming flexible DC converter was set to 5MW. At the first second, the grid frequency stepped from 50Hz to 50.5Hz and maintained for 1 second before returning to 50Hz. During the simulation, the damping element D of the typical virtual synchronous machine was set to 5000. In the proposed method, the damping element D is set to 5000, and K is set to 1 / 600.

[0090] Depend on Figure 6 As can be seen, both the existing damping strategy and the proposed damping link grid control generate damping power during sudden frequency changes. This power blocks sudden changes in grid frequency and promotes system frequency stability. While the existing damping strategy results in an active power deviation of 5MW, the proposed optimized damping strategy restores the power command value after a short period of damping, ensuring stable system power after damping.

[0091] Example 2:

[0092] Please refer to Figure 2 Based on the same inventive concept, an embodiment of the present invention discloses a grid-type flexible DC converter damping control system, comprising: a normalized power deviation calculation module M1, an angular frequency deviation calculation module M2, a voltage data generation module M3, and a signal control module M4;

[0093] The normalized power deviation calculation module M1 is used to generate a normalized power deviation based on a reference value of the active power of the grid-connected flexible DC converter, a current output value and a rated angular frequency of the grid-connected system.

[0094] Furthermore, the normalized power deviation calculation module M1 includes: an original power deviation calculation unit and a normalization processing unit;

[0095] The original power deviation calculation unit is used to perform deviation calculation on the reference value and current output value of the active power of the grid-type flexible DC converter to obtain the original power deviation;

[0096] The normalization processing unit is used to perform normalization processing on the original power deviation according to the rated angular frequency of the grid-connected system to obtain a normalized power deviation.

[0097] In this preferred embodiment, the original power deviation calculation unit and the normalization processing unit obtain the original power deviation by performing deviation calculation on the active power reference value and the current output value of the grid-connected flexible DC converter, directly extract the instantaneous error signal between the power instruction and the actual output, and provide a basic input for closed-loop control; by normalizing the original power deviation based on the rated angular frequency of the grid-connected system, the dimensional difference under different grid frequency scenarios is eliminated, thereby improving the cross-operating condition versatility of the control strategy.

[0098] The angular frequency deviation calculation module M2 is used to perform deviation superposition processing based on the preset damping compensation power deviation and the normalized power deviation to obtain a first power deviation, and to perform an integration operation on the first power deviation based on the preset inertia coefficient to obtain an angular frequency deviation; wherein, after each angular frequency deviation is generated, the damping compensation power deviation is updated based on the angular frequency deviation and the preset angular frequency deviation compensation amount; and after each update of the damping compensation power deviation, the angular frequency deviation compensation amount is updated based on the first power deviation and the updated damping compensation power deviation.

[0099] Furthermore, the angular frequency deviation calculation module M2 includes: a first updating unit;

[0100] The first updating unit is configured to perform a damping proportional operation on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine each time the angular frequency deviation is generated, to obtain an updated damping compensation power deviation; wherein the damping proportional operation is calculated as follows:

[0101] ;in, represents the damping compensation power deviation, D represents the damping coefficient, represents the angular frequency deviation, Indicates the angular frequency deviation compensation amount.

[0102] In this preferred embodiment, the first update unit performs a damping proportional operation on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine after each angular frequency deviation is generated, uses the damping coefficient to quantify the dynamic deviation weight, and quickly adjusts the damping compensation power deviation to suppress transient power fluctuations.

[0103] Furthermore, the angular frequency deviation calculation module M2 further includes: a second updating unit;

[0104] The second updating unit is configured to perform a joint integral compensation operation according to a preset adjustment coefficient, the first power deviation, and the updated damping compensation power deviation after each update of the damping compensation power deviation to obtain an updated angular frequency deviation compensation amount;

[0105] The formula for the joint integral compensation operation is:

[0106] ; Where K represents the adjustment coefficient, s represents the Laplace operator, Indicates the first power deviation.

[0107] In this preferred embodiment, the second update unit performs a joint integral compensation operation based on the preset adjustment coefficient, the first power deviation and the updated damping compensation power deviation after each update of the damping compensation power deviation, and gradually eliminates the steady-state error through the integral action to ensure that the power output strictly tracks the instruction value; by jointly adjusting the forward power deviation and the feedback compensation amount, a dynamic compensation mechanism is formed to enhance the system's adaptive correction capability for long-term deviations.

[0108] The voltage data generating module M3 is configured to generate voltage reference data according to the angular frequency deviation and the output voltage amplitude of the virtual synchronous machine.

[0109] Furthermore, the voltage data generating module M3 includes: a phase generating unit and a voltage data generating unit;

[0110] The phase generating unit is configured to perform a phase synthesis integral operation on the angular frequency deviation and the rated angular frequency to generate an output phase of the virtual synchronous machine;

[0111] The voltage data generating unit is configured to perform polar coordinate transformation processing according to the output voltage amplitude and the output phase of the virtual synchronous machine to generate a first voltage reference value and a second voltage reference value as voltage reference data.

[0112] In this preferred embodiment, the phase generation unit and the voltage data generation unit generate a continuous phase signal synchronized with the power grid by synthesizing the dynamic angular frequency deviation and the rated angular frequency and integrating them, thereby ensuring that the output phase of the virtual synchronous machine dynamically matches the grid reference frequency, thereby improving the synchronization stability under weak power grids; the integral operation smoothes the sudden change in angular frequency and suppresses the power oscillation caused by transient phase jumps. The output voltage amplitude and phase in the polar coordinate system are converted to the voltage reference value in the stationary coordinate system to adapt to the requirements of the converter modulation algorithm and realize the precise mapping of power control instructions to voltage waveforms; the polar coordinate transformation retains the orthogonal characteristics of amplitude and phase through trigonometric function operations, ensuring the amplitude consistency and phase continuity of the voltage reference value, thereby improving the quality of the converter output waveform and the dynamic tracking accuracy.

[0113] The signal control module M4 is configured to generate a pulse width modulation signal according to the voltage reference data, and control the grid-type flexible DC converter according to the pulse width modulation signal.

[0114] In this embodiment, the signal control module M4 converts the voltage reference data into a pulse width modulation signal and dynamically adjusts the converter output based on the modulation signal to ensure fast tracking of active power and grid frequency, thereby improving transient response speed and steady-state execution efficiency.

[0115] In summary, compared with the prior art, the embodiments of the present application have the following beneficial effects: by generating a normalized power deviation based on the active power reference value of the grid-type flexible DC converter, the current output value and the rated angular frequency of the grid-connected system, the power deviation is converted into a frequency-related per-unit value to adapt to the dimensional unification requirements of the subsequent control link; by superimposing the preset damping compensation power deviation and the normalized power deviation, a closed-loop feedback mechanism is formed to enhance the transient response speed; the first power deviation is integrated by a preset inertia coefficient to simulate the mechanical inertia characteristics of the synchronous generator and suppress the power oscillation caused by the sudden change of the grid frequency; by The damping compensation power deviation is dynamically updated based on the difference between the first power deviation and the preset angular frequency deviation compensation, and the damping compensation is adjusted in real time to optimize the transient damping performance; by updating the angular frequency deviation compensation based on the first power deviation and the updated damping compensation power deviation, the steady-state power deviation is eliminated by combined integral compensation to improve the control accuracy; by integrating the angular frequency deviation and the output voltage amplitude, voltage reference data adapted to the current working conditions is generated to ensure real-time matching of the power instruction and the system state; the voltage reference data is converted into a pulse width modulation signal, and the converter output is dynamically adjusted based on the modulation signal to ensure rapid tracking of active power and grid frequency, thereby improving transient response speed and steady-state execution efficiency. Through the synergistic combination design of the above-mentioned features, this solution constructs local negative feedback within the damping link, avoids direct feedback of the angular frequency deviation, improves steady-state power control accuracy and transient damping enhancement, and solves the contradiction between stability and accuracy in traditional virtual synchronous machine control.

[0116] Example 3:

[0117] Figure 3 The structure diagram of a grid-type flexible DC converter damping control device of the present application is presented. Figure 3 As shown, the grid-type flexible DC converter damping control device may include: a processor N1, a memory N2, a data interface N3 and a communication bus N4.

[0118] Among them: the processor N1, the memory N2, and the data interface N3 communicate with each other through the communication bus N4; the data interface N3 is used for data communication with other devices such as an input device or an output device; the processor N1 is used to execute the program N5, which can specifically execute the relevant steps in any of the above-mentioned embodiments of the damping control method for a grid-type flexible direct current converter.

[0119] Specifically, the program N5 may include program code, which includes computer-executable instructions.

[0120] Processor N1 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. The one or more processors included in the grid-type flexible DC converter damping control device may be processors of the same type, such as one or more CPUs, or processors of different types, such as one or more CPUs and one or more ASICs.

[0121] The memory N2 is used to store the program N5. The memory N2 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0122] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. In addition, the embodiments of the present application are not directed to any particular programming language.

[0123] Example 4:

[0124] An embodiment of the present invention also provides a computer-readable storage medium, which stores at least one executable instruction. When the executable instruction is run on a grid-type flexible DC converter damping control device / system, the grid-type flexible DC converter damping control device / system executes a grid-type flexible DC converter damping control method in any of the above method embodiments.

[0125] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. Similarly, in order to streamline the application and help understand one or more of the various inventive aspects, in the above description of the exemplary embodiments of the application, the various features of the embodiments of the application are sometimes grouped together into a single embodiment, figure, or description thereof. Wherein, the claims that follow the specific embodiment are hereby clearly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the application.

[0126] Those skilled in the art will appreciate that the modules in the devices of the embodiments can be adaptively changed and installed in one or more devices different from the embodiments. The modules, units, or components in the embodiments can be combined into one module, unit, or component, and furthermore, they can be divided into multiple submodules, subunits, or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive.

Claims

1. A damping control method for a grid-type flexible DC converter, characterized in that: include: Generate a normalized power deviation based on the active power reference value of the grid-connected flexible DC converter, the current output value, and the rated angular frequency of the grid-connected system; A deviation superposition process is performed on the preset damping compensation power deviation and the normalized power deviation to obtain a first power deviation, and an integral operation is performed on the first power deviation according to a preset inertia coefficient to obtain an angular frequency deviation; wherein, after each angular frequency deviation is generated, the damping compensation power deviation is updated according to the angular frequency deviation and a preset angular frequency deviation compensation amount; and after each update of the damping compensation power deviation, the angular frequency deviation compensation amount is updated according to the first power deviation and the updated damping compensation power deviation. generating voltage reference data according to the angular frequency deviation and the output voltage amplitude of the virtual synchronous machine; generating a pulse width modulation signal according to the voltage reference data, and controlling the grid-type flexible direct current converter according to the pulse width modulation signal; The angular frequency deviation compensation amount is updated according to the first power deviation and the updated damping compensation power deviation each time after the damping compensation power deviation is updated, including: After each update of the damping compensation power deviation, a joint integral compensation operation is performed according to the preset adjustment coefficient, the first power deviation and the updated damping compensation power deviation to obtain an updated angular frequency deviation compensation amount; The formula for the joint integral compensation operation is: ; Where K represents the adjustment coefficient, s represents the Laplace operator, Indicates the first power deviation.

2. A damping control method for a grid-type flexible DC converter according to claim 1, characterized in that: The generating of the normalized power deviation based on the active power reference value of the grid-connected flexible DC converter, the current output value and the rated angular frequency of the grid-connected system includes: Performing deviation calculation on the reference value and current output value of the active power of the grid-type flexible DC converter to obtain the original power deviation; The original power deviation is normalized according to the rated angular frequency of the grid-connected system to obtain a normalized power deviation.

3. A damping control method for a grid-type flexible DC converter according to claim 1, characterized in that: The damping compensation power deviation is updated according to the angular frequency deviation and a preset angular frequency deviation compensation amount each time the angular frequency deviation is generated, including: After each angular frequency deviation is generated, a damping proportional operation is performed on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine to obtain an updated damping compensation power deviation; wherein the formula for the damping proportional operation is: ;in, represents the damping compensation power deviation, D represents the damping coefficient, represents the angular frequency deviation, Indicates the angular frequency deviation compensation amount.

4. A damping control method for a grid-type flexible DC converter according to claim 1, characterized in that: Generating voltage reference data according to the angular frequency deviation and the output voltage amplitude of the virtual synchronous machine includes: Performing a phase synthesis integration operation on the angular frequency deviation and the rated angular frequency to generate an output phase of the virtual synchronous machine; Polar coordinate transformation is performed according to the output voltage amplitude and the output phase of the virtual synchronous machine to generate a first voltage reference value and a second voltage reference value as voltage reference data.

5. A grid-type flexible DC converter damping control system, characterized in that: include: Normalized power deviation calculation module, angular frequency deviation calculation module, voltage data generation module and signal control module; The normalized power deviation calculation module is configured to generate a normalized power deviation based on a reference value of the active power of the grid-connected flexible DC converter, a current output value, and a rated angular frequency of the grid-connected system; The angular frequency deviation calculation module is configured to perform deviation superposition processing based on a preset damping compensation power deviation and the normalized power deviation to obtain a first power deviation, and perform an integration operation on the first power deviation based on a preset inertia coefficient to obtain an angular frequency deviation; wherein, after each angular frequency deviation is generated, the damping compensation power deviation is updated based on the angular frequency deviation and a preset angular frequency deviation compensation amount; and after each update of the damping compensation power deviation, the angular frequency deviation compensation amount is updated based on the first power deviation and the updated damping compensation power deviation. The voltage data generating module is configured to generate voltage reference data according to the angular frequency deviation and the output voltage amplitude of the virtual synchronous machine; The signal control module is configured to generate a pulse width modulation signal according to the voltage reference data, and control the grid-type flexible DC converter according to the pulse width modulation signal; The angular frequency deviation calculation module includes: a second updating unit; The second updating unit is configured to perform a joint integral compensation operation according to a preset adjustment coefficient, the first power deviation, and the updated damping compensation power deviation after each update of the damping compensation power deviation to obtain an updated angular frequency deviation compensation amount; The formula for the joint integral compensation operation is: ; Where K represents the adjustment coefficient, s represents the Laplace operator, Indicates the first power deviation.

6. A grid-type flexible DC converter damping control system according to claim 5, characterized in that: The normalized power deviation calculation module includes: an original power deviation calculation unit and a normalization processing unit; The original power deviation calculation unit is used to perform deviation calculation on the reference value and current output value of the active power of the grid-type flexible DC converter to obtain the original power deviation; The normalization processing unit is used to perform normalization processing on the original power deviation according to the rated angular frequency of the grid-connected system to obtain a normalized power deviation.

7. A grid-type flexible DC converter damping control system according to claim 5, characterized in that: The angular frequency deviation calculation module includes: a first updating unit; The first updating unit is configured to perform a damping proportional operation on the angular frequency deviation and the angular frequency deviation compensation amount according to the damping coefficient of the virtual synchronous machine each time the angular frequency deviation is generated, to obtain an updated damping compensation power deviation; wherein the damping proportional operation is calculated as follows: ;in, represents the damping compensation power deviation, D represents the damping coefficient, represents the angular frequency deviation, Indicates the angular frequency deviation compensation amount.

8. A damping control device for a grid-type flexible DC converter, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is loaded into the processor, the steps of the damping control method of a grid-type flexible DC converter according to any one of claims 1 to 4 are implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of a damping control method for a grid-type flexible DC converter according to any one of claims 1 to 4 are implemented.

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