A method and device for calculating commutation angle of multi-source adaptive commutation converter

Abstract

The application discloses a multi-source adaptive commutation converter commutation angle calculation method and device. The method comprises the following steps: establishing an equivalent circuit model of an SLCC commutation stage, determining a commutation circuit equation during commutation based on an equivalent circuit diagram during commutation; based on a positive sequence fundamental wave assumption, equivalent participation of a SVG valve side voltage in commutation is realized by using a fundamental wave component of the SVG valve side voltage, and the commutation current equation is integrated in a commutation interval to obtain a fast commutation angle calculation formula; based on a low-order control equivalent model of SVG control, a fast incremental voltage vector across an SVG connecting inductor is obtained in a short time window of commutation, the fast incremental voltage vector is projected along a commutation direction, and the control equivalent voltage area is obtained by integrating the fast incremental voltage vector in the commutation interval; the control equivalent voltage area is substituted into the fast commutation angle calculation formula to obtain a control equivalent commutation angle calculation method considering a fast control response of the SVG; and the control equivalent commutation angle calculation method is used to calculate the control equivalent commutation angle considering the fast control response of the SVG.

Description

Technical Field

[0001] This invention relates to the field of power system simulation and analysis technology, and more specifically, to a method and apparatus for calculating the commutation angle of a multi-source adaptive commutation converter. Background Technology

[0002] The Multi-source Self-adaptation SVG and Line Commutation Converter (SLCC) improves commutation characteristics by directly connecting the SVG to the converter transformer side and in parallel with the thyristor converter valve on the basis of a conventional LCC converter. It utilizes the dynamic reactive power compensation and harmonic filtering capabilities of the SVG to effectively enhance the inverter station's ability to resist commutation failure.

[0003] In quasi-steady-state modeling and power flow calculations for SLCCs, the commutation angle μ is a key parameter determining DC voltage, power factor, and AC / DC switching power. Current techniques for calculating the commutation angle of SLCCs mainly suffer from the following problems: (1) The traditional LCC commutation angle formula cannot reflect the influence of SVG: The traditional LCC commutation angle formula only considers the voltage and commutation reactance of the converter transformer side. However, after the SVG is connected to the valve side in SLCC, its output voltage and LCC have a coupling effect at the PCC point. The injection effect of SVG compensation current on the commutation process causes a significant deviation in the traditional formula. Existing studies usually simplify the receiving-end voltage source and SVG as a single equivalent voltage source, lacking in-depth analysis of how SVG compensation current affects the commutation process.

[0004] (2) Lack of two types of calculation methods that balance accuracy and efficiency: In AC / DC power flow iteration, the commutation angle needs to be calculated repeatedly. High-precision models have a large computational load, while simple fundamental wave models lack sufficient accuracy. Existing technologies lack classification calculation strategies for different application scenarios (rapid iteration vs. fine verification).

[0005] (3) Lack of systematic evaluation method for simplified model error: When a simplified model is used to replace the complete control model to calculate the commutation angle, the existing technology lacks a systematic quantitative characterization method for the frequency domain error of the simplified control model relative to the complete control model, making it difficult to evaluate the applicability and response deviation of the simplified model before engineering application. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method and apparatus for calculating the commutation angle of a multi-source adaptive commutation converter.

[0007] According to one aspect of the present invention, a method for calculating the commutation angle of a multi-source adaptive commutator is provided, comprising: An equivalent circuit model for the commutation stage of SLCC is established, and the commutation circuit equations during the commutation period are determined based on the equivalent circuit diagram during the commutation period. Based on the positive sequence fundamental wave assumption, the SVG valve side voltage is used as its fundamental wave component to participate in the commutation. The commutation current equation is integrated within the commutation interval to obtain the fast commutation angle calculation formula. Based on a low-order equivalent control model of SVG control, the fast incremental voltage vector across the SVG-connected inductor is obtained within a short commutation time window. The control equivalent voltage area is obtained by projecting along the commutation direction and integrating within the commutation interval. Substituting the control equivalent voltage area into the fast commutation angle formula, we obtain the control equivalent commutation angle calculation method that takes into account the fast control response of SVG. Based on the method of calculating the equivalent commutation angle of control, the equivalent commutation angle of control taking into account the fast control response of SVG is calculated.

[0008] Optionally, during commutation, the voltage on the converter transformer side and the voltage on the SVG valve side are applied together to the series inductance of the commutation circuit, which together determine the transient change of the commutation current. The expression for the commutation current equation during commutation is: In the formula, For the voltage of line AB on the converter transformer side, , These are the A-phase voltage and B-phase voltage on the converter transformer side, respectively. The AB line voltage output by the SVG. , These are the A-phase voltage and B-phase voltage output from the SVG, respectively. L T and L S These are the commutator equivalent inductance and the SVG connection inductance, respectively. i ta , i sa These represent the currents flowing through the converter transformer and the SVG, respectively. This is the commutation current.

[0009] Optionally, the commutation start and end points are: and Satisfying boundary conditions , For the commutation current equation in The expression for the over-integral is: The formula for calculating the fast commutation angle is: In the formula, , These are the fundamental voltages on the grid side and the SVG side, respectively. X T For converter transformer reactor, X S For SVG equivalent connection reactance, U G This refers to the grid-side voltage amplitude. U s This is the voltage at the SVG terminal. i d It is direct current. α For trigger angle, μ To change the phase angle, This represents the phase angle of the SVG voltage.

[0010] Optionally, the expression for the low-order control equivalent model is: In the formula, τ is the time constant. k p Let be the scaling factor, s be the Laplace operator, I be the 3rd order identity matrix, and Q be the state matrix. u abc These are the three-phase voltage values ​​for phases a, b, and c. i abc,ref The reference values ​​for the three-phase currents of a, b, and c are provided. G u sim (s), G i sim (s) These are the simplified transfer functions for the voltage and current paths, respectively.

[0011] The low-order control equivalent model is obtained by simplifying the equivalent transfer function of the complete system, where the expression of the equivalent transfer function of the complete system is: In the formula, τ is the time constant. kp, k i Here, represents the PI proportional-integral parameter, s is the Laplace operator, I is the 3rd order identity matrix, and Q is the state matrix. u abc These are the three-phase voltage values ​​for phases a, b, and c. i abc,ref , i abc,ref These are the three-phase currents (A, B, and C) and their reference values, respectively. ω s For the power grid base frequency, ε For control system constants, H(s) , N(s) , M(s) This is a transfer function expression, which has no practical meaning.L The equivalent inductance of the SVG; G u (s), G i (s) These are the complete transfer functions for the voltage and current paths, respectively.

[0012] Optionally, the formula for calculating the control equivalent voltage area is: In the formula, The commutation direction vector; Let ω be the local electrical angle and ω be the angular velocity. t For time, μ To change the phase angle, V L Γ(μ) is the fast incremental voltage vector connecting the two ends of the inductor to the SVG, and Γ(μ) is the equivalent voltage area.

[0013] Optionally, the expression for the control equivalent commutation angle calculation equation, taking into account the fast control response of SVG, is: In the formula, and These are the equivalent reactance of the converter transformer and the SVG connection reactance, respectively. This represents the effective value of the fundamental line voltage on the converter transformer side. I d Γ(μ) represents the DC current, and Γ(μ) represents the area of ​​the equivalent voltage.

[0014] Optionally, it also includes: defining the first zero-crossing angle of the SVG fast voltage in the commutation direction. When the control equivalent commutation angle is less than the first zero-crossing angle When the commutation angle is greater than or equal to the first zero-crossing angle, the commutation angle is calculated using the fast commutation angle formula; when the control equivalent commutation angle is greater than or equal to the first zero-crossing angle, the control equivalent commutation angle is used.

[0015] Optionally, it also includes: The error transfer function between the low-order control equivalent model and the equivalent transfer function of the complete system is defined. The response error is quantitatively characterized based on the induced gain and norm, and the peak frequency of the dominant error spectrum is estimated by first-order perturbation analysis. The error transfer function includes: current reference channel transfer function deviation. Deviation from the transfer function of the voltage path :

[0016] In the formula, G u (s), G i(s) These are the complete transfer functions for the voltage and current paths, respectively. G u sim (s), G i sim (s) These are the simplified transfer functions for the voltage and current paths, respectively. ΔG u (s), ΔG i (s) These are the deviation values ​​of the voltage and current path transfer functions, respectively.

[0017] The output error must meet the following requirements: in, It is the supremum of the maximum singular value; , These are the 2-norms of the three-phase current reference value and the voltage deviation, respectively; G u 、G i These are the voltage and current path transfer functions, respectively.

[0018] Optionally, the peak frequency of the dominant error spectrum is located in the power frequency and its adjacent frequency range; when the integral gain is less than a preset threshold and the modulation loop response time is less than a preset threshold, the response error of the low-order control equivalent model and the equivalent transfer function of the complete system in the frequency range adjacent to the power frequency is less than a preset tolerance.

[0019] According to another aspect of the present invention, a commutation angle calculation device for a multi-source adaptive commutator is provided, comprising: A module is established to build an equivalent circuit model for the commutation stage of SLCC. Based on the equivalent circuit diagram during commutation, the commutation circuit equations during commutation are determined. The first integration module is used to integrate the SVG valve-side voltage with its fundamental component as equivalent to participate in the commutation based on the positive sequence fundamental wave assumption, and to obtain the fast commutation angle calculation formula by integrating the commutation current equation within the commutation interval. The second integration module is used to obtain the fast incremental voltage vector across the inductor connected to the SVG within the short commutation time window, based on the low-order control equivalent model of SVG control. The control equivalent voltage area is obtained by projecting along the commutation direction and integrating within the commutation interval. The substitution module is used to substitute the control equivalent voltage area into the fast commutation angle formula to obtain the control equivalent commutation angle calculation method that takes into account the fast control response of SVG. The calculation module is used to calculate the control equivalent commutation angle based on the control equivalent commutation angle calculation method, taking into account the fast control response of SVG.

[0020] According to another aspect of the present invention, a computer-readable storage medium is provided, the storage medium storing a computer program for performing the methods described in any of the above aspects of the present invention.

[0021] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: a processor; a memory for storing executable instructions of the processor; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the method described in any of the preceding aspects of the present invention.

[0022] Therefore, this invention provides a fast estimation formula based on the positive-sequence fundamental wave assumption, applicable to power flow main cycles requiring multiple iterations; it derives a fine commutation angle correction formula based on the equivalent transfer functions of the SVG current inner loop and modulation loop; and it defines an error transfer function between the low-order model and the complete model, based on induced... Gain and The norm is used to quantitatively characterize the response error, and the first-order perturbation analysis is used to estimate the peak frequency of the dominant error spectrum. By constructing two complementary commutation angle calculation methods and performing frequency domain error analysis on the simplified model, a solution that balances accuracy and efficiency is provided for the engineering calculation of SLCC commutation angle. Attached Figure Description

[0023] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures: Figure 1 This is a flowchart illustrating a method for calculating the commutation angle of a multi-source adaptive commutator provided in an exemplary embodiment of the present invention. Figure 2 This is an equivalent circuit diagram of the SLCC commutation stage provided in an exemplary embodiment of the present invention; Figure 3 This is an equivalent block diagram of the current inner loop and electrical model provided in an exemplary embodiment of the present invention; Figure 4 This is an equivalent block diagram of the d-axis current inner loop and electrical model provided in an exemplary embodiment of the present invention; Figure 5 This is a schematic diagram comparing the analytical solution and PSCAD simulation when the inner loop ratio parameter is 20, provided by an exemplary embodiment of the present invention. Figure 6 This is a schematic diagram comparing the analytical solution and PSCAD simulation when the inner loop ratio parameter is 50, provided by an exemplary embodiment of the present invention. Figure 7 This is a schematic diagram of the commutation angle calculation device for a multi-source adaptive commutator provided in an exemplary embodiment of the present invention; Figure 8This is the structure of an electronic device provided in an exemplary embodiment of the present invention. Detailed Implementation

[0024] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0025] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0026] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0027] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0028] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0029] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0030] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0031] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0032] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0033] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0035] The embodiments of this invention can be applied to electronic devices such as terminal devices, computer systems, and servers, and can operate together with a wide range of other general-purpose or special-purpose computing system environments or configurations. Well-known examples of terminal devices, computing systems, environments, and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, and servers include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments including any of the above systems, etc.

[0036] Electronic devices such as terminal devices, computer systems, and servers can be described in the general context of computer system executable instructions (such as program modules) executed by a computer system. Typically, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in distributed cloud computing environments, where tasks are executed by remote processing devices linked through communication networks. In distributed cloud computing environments, program modules can reside on local or remote computing system storage media, including storage devices.

[0037] Exemplary methods Figure 1 This is a flowchart illustrating a method for calculating the commutation angle of a multi-source adaptive commutator converter according to an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as... Figure 1 As shown, the commutation angle calculation method 100 for a multi-source adaptive commutator includes the following steps: Step 101: Establish the equivalent circuit model of the SLCC commutation stage, and determine the commutation circuit equations during the commutation period based on the equivalent circuit diagram during the commutation period. Step 102: Based on the positive sequence fundamental wave assumption, the SVG valve side voltage is used as its fundamental wave component to participate in the commutation. The commutation current equation is integrated in the commutation interval to obtain the fast commutation angle calculation formula. Step 103: Based on the low-order equivalent control model of SVG control, obtain the fast incremental voltage vector across the SVG-connected inductor within the short commutation time window. The control equivalent voltage area is obtained by projecting along the commutation direction and integrating within the commutation interval. Step 104: Substitute the control equivalent voltage area into the fast commutation angle formula to obtain the control equivalent commutation angle calculation method that takes into account the fast control response of SVG. Step 105: Calculate the equivalent commutation angle of the control system, taking into account the fast control response of the SVG, based on the control equivalent commutation angle calculation method.

[0038] Specifically, the purpose of the invention is to provide an analytical calculation method and error evaluation method for the commutation angle of an SLCC DC system. By constructing two complementary commutation angle calculation methods and performing frequency domain error analysis on the simplified model, the invention provides a solution that balances accuracy and efficiency for the engineering calculation of the commutation angle of SLCC.

[0039] The core of this invention lies in: First, a fast estimation formula is given based on the positive-sequence fundamental wave assumption, applicable to power flow main cycles requiring multiple iterations; Second, a fine commutation angle correction formula is derived based on the equivalent transfer functions of the SVG current inner loop and modulation loop; Third, by defining the error transfer function between the low-order model and the complete model, a formula based on induced... Gain and The norm is used to quantitatively characterize the response error, and first-order perturbation analysis is used to estimate the peak frequency of the dominant error spectrum.

[0040] Step 1: Establish the equivalent circuit model of the SLCC commutation stage The equivalent circuit of the SLCC commutation stage is as follows: Figure 2 As shown (upper valve A→B commutation, lower valve C is on). During commutation, the voltage on the converter transformer side and the voltage on the SVG valve side are combined across the series inductance of the commutation circuit, jointly determining the transient change of the commutation current. Based on KVL and KCL, the commutation current equation during commutation is:

[0041] in, For the voltage of line AB on the converter transformer side, The AB line voltage output by the SVG. L T and L S These are the commutator equivalent inductance and the SVG connection inductance, respectively. This is the commutation current.

[0042] Step 2: Fast commutation angle estimation based on SVG fundamental equivalent When only the primary side electrical quantities are considered and the rapid influence of the SVG control loop on the commutation angle is ignored, the SVG valve-side voltage is equivalent to its fundamental component participating in the commutation.

[0043] The grid-side and SVG fundamental phase voltages are respectively:

[0044] Commutation start and end and Satisfying boundary conditions , For the commutation current equation in The integral above is given by the following formula:

[0045] The formula for quick angle switching is obtained as follows:

[0046] in, , , which are the fundamental voltages on the grid side and the SVG side, respectively; , These are the equivalent reactance of the converter transformer and the SVG connection reactance, respectively.

[0047] This formula is applicable to the rapid iteration of commutation angle in the main AC / DC power flow cycle. It requires little computation and can meet the accuracy requirements of engineering projects.

[0048] Step 3: Fine calculation of commutation angle based on the control equivalent model The SVG in SLCC adopts a dual closed-loop vector control structure of "power outer loop + current inner loop". During the commutation process (approximately 0.25-0.75ms for a 50Hz system, corresponding to 5°-15° electrical angle), the time scale is on the same order of magnitude as the bandwidth of the current inner loop, and the inner loop dominates the formation of the modulation wave during commutation.

[0049] 3.1 Establish the inner current loop and electrical model (e.g.) Figure 3 (As shown) Equivalent transfer function like Figure 4 As shown, in the dq0 coordinate system, the integral term of PI adopts a bleeder type, with parameters as follows: , , The modulation stage uses first-order inertia and a time constant. The above steps can be written as:

[0050] Considering the asymmetry caused by commutation, the reference frame is transformed back to the stationary coordinate system. P Let be the Park transformation matrix, denoted as... ,and ( (Base frequency of the power grid):

[0051] After eliminating the zero order, to facilitate calculation, we introduce:

[0052] The complete system input-output relationship, i.e., the equivalent transfer function, is:

[0053] 3.2 Low-order equivalent model To reduce order and coupling, the integral element in the PI controller and the coupling term Q in the M(s) matrix are ignored, and the simplified transfer function is adopted as follows:

[0054] This simplified model can reflect the rapid impact of the inner loop proportional gain and modulation stage on the commutation voltage, while significantly reducing computational complexity.

[0055] Based on the aforementioned low-order control equivalent model, the fast incremental voltage vector across the SVG connected to the inductor within the short commutation time window can be obtained. For commutation from phase A to phase B, the commutation direction vector is defined as follows: Local electrical angle Measuring begins from the actual commutation start moment. The SVG fast voltage response is projected along the commutation direction and integrated over the commutation interval; the control equivalent voltage area is defined as: Substituting the equivalent voltage area of ​​the control into the integral relationship of the commutation current, we can obtain the equation for calculating the commutation angle considering the fast control response of the SVG: in, and These are the equivalent reactance of the converter transformer and the SVG connection reactance, respectively. Let be the effective value of the fundamental line voltage on the converter transformer side. The equivalent commutation angle considering the fast control response of the SVG can be obtained by solving the above equation.

[0056] To determine the applicability of the positive-sequence fundamental fast formula in control-sensitive operating conditions, the first zero-crossing angle of the SVG fast voltage in the commutation direction is further defined. For commutation from phase A to phase B, the first zero-crossing angle satisfies: When the control equivalent commutation angle satisfies When the SVG fast commutation drive voltage remains positive before commutation is complete, the positive sequence fundamental frequency formula can be used as a fast estimation method; when When the fast commutation drive voltage has already crossed zero or reversed before the current transfer is completed, the positive sequence fundamental formula should not be used alone. Instead, the above-mentioned control equivalent commutation angle formula or a more refined time-domain calculation should be used for correction.

[0057] Step 4: Error analysis and evaluation of simplified and complete control models To quantitatively illustrate the deviation of the simplified model in step 3.2 from the complete model in step 3.1, the frequency domain error transfer function analysis method is introduced.

[0058] 4.1 Define the error propagation function Define the current reference channel transfer function deviation separately. Deviation from the transfer function of the voltage path :

[0059] 4.2 Frequency Domain Error Upper Bound Estimation Based on Maximum Singular Values Induction based on stable LTI system Gain ( According to the norm theory and the Parseval / Plancherel theorem, with zero initialization, for any input, the output error satisfies:

[0060] in, It is the supremum of the maximum singular value.

[0061] 4.3 First-order perturbation analysis of dominant spectral peak frequencies Since the rotation coupling matrix Q is a real antisymmetric matrix, its singular values ​​are equal to the moduli of its eigenvalues. In the eigenspace of the unitary matrix U, the error channel is decomposed into three scalar channels.

[0062] Taking the zero eigenvalue channel as an example, its error propagation function is:

[0063] exist On the frequency axis, the poles of this equation are determined only by third-order factors. The first-order approximate pole is determined to be:

[0064] Analysis using the above method shows that the dominant frequencies of the three characteristic channels are all concentrated in the power frequency neighborhood (50Hz and nearby sidebands).

[0065] Therefore, the maximum gain of the error transfer function of the current reference channel is approximately:

[0066] Correspondingly, the maximum gain of the error transfer function of the voltage reference channel is approximately as follows for different eigenvalues:

[0067] 4.4 Error Assessment Criteria When the integral gain is small, the modulation loop response is fast, and the influence of the proportional element's equivalent damping on the series reactance is dominant, the low-order transfer model and the complete transfer model have small response errors in the power frequency and its adjacent frequency range of engineering interest. Therefore, they can be used to approximate the calculation of the fast voltage response of SVG within a short commutation time window.

[0068] In a specific embodiment of the present invention, a simulation comparison based on PSCAD is performed. With an angular frequency of 100π, a series inductance of 8.5mH, an inner loop current scaling factor of 20, and a time constant of 0.00023, the analytical solution is compared with the actual electromagnetic transient output of the constructed SLCC as follows. Figure 5 and Figure 6 As shown, when They are respectively and hour, Figure 5 and Figure 6 The root mean square errors of the analytical solution and simulation results are 4.03kV and 4.41kV, respectively. Within the initial 0.15ms of commutation, due to the sampling-calculation-PWM update delay in the digital current loop, after an external voltage step, the inverter output maintains the previous cycle value within the time window from the sampling moment to the new duty cycle taking effect, and the control action has not yet intervened. Affected by this zero-order hold, the equivalent excitation across the inductor is approximately a constant step within 0.15ms; after 0.15ms, the control loop begins to cancel the disturbance, attenuating according to the derived voltage input. Meanwhile, considering that the voltage compensation stage may be more complex in practice, and ignoring the influence of the current reference value, there is a certain difference from the actual inductor voltage. However, compared to the fundamental commutation angle model in the previous section, this model is more accurate.

[0069] Therefore, this invention provides a solution that balances accuracy and efficiency for the engineering calculation of SLCC commutation angle by constructing two complementary commutation angle calculation methods and performing frequency domain error analysis on the simplified model.

[0070] Exemplary device Figure 7 This is a schematic diagram of the commutation angle calculation device for a multi-source adaptive commutator provided in an exemplary embodiment of the present invention. Figure 7 As shown, the device 700 includes: Module 710 is established to build an equivalent circuit model of the SLCC commutation stage and determine the commutation circuit equations during the commutation period based on the equivalent circuit diagram during the commutation period. The first integration module 720 is used to integrate the SVG valve-side voltage with its fundamental component as equivalent to participate in the commutation based on the positive sequence fundamental wave assumption, and to obtain the fast commutation angle calculation formula by integrating the commutation current equation within the commutation interval. The second integrator module 730 is used to obtain the fast incremental voltage vector across the inductor connected to the SVG within a short commutation time window, based on the low-order control equivalent model of SVG control. The control equivalent voltage area is obtained by projecting along the commutation direction and integrating within the commutation interval. Substitute module 740 to substitute the control equivalent voltage area into the fast commutation angle formula to obtain the control equivalent commutation angle calculation method that takes into account the fast control response of SVG. The calculation module 750 is used to calculate the control equivalent commutation angle, which takes into account the fast control response of SVG, based on the control equivalent commutation angle calculation method.

[0071] Optionally, during commutation, the voltage on the converter transformer side and the voltage on the SVG valve side are applied together to the series inductance of the commutation circuit, which together determine the transient change of the commutation current. The expression for the commutation current equation during commutation is: In the formula, For the voltage of line AB on the converter transformer side, , These are the A-phase voltage and B-phase voltage on the converter transformer side, respectively. The AB line voltage output by the SVG. , These are the A-phase voltage and B-phase voltage output from the SVG, respectively. L T and L S These are the commutator equivalent inductance and the SVG connection inductance, respectively. i ta , i sa These represent the currents flowing through the converter transformer and the SVG, respectively. This is the commutation current.

[0072] Optionally, the commutation start and end points are: and Satisfying boundary conditions , For the commutation current equation in The expression for the over-integral is: The formula for calculating the fast commutation angle is: In the formula, , These are the fundamental voltages on the grid side and the SVG side, respectively. X T For converter transformer reactor, X S For SVG equivalent connection reactance, U G This refers to the grid-side voltage amplitude. U s This is the voltage at the SVG terminal. i d It is direct current. α For trigger angle, μ To change the phase angle, This represents the phase angle of the SVG voltage.

[0073] Optionally, the expression for the low-order control equivalent model is: In the formula, τ is the time constant. k p Let be the scaling factor, s be the Laplace operator, I be the 3rd order identity matrix, and Q be the state matrix. u abc These are the three-phase voltage values ​​for phases a, b, and c. i abc,ref The reference values ​​for the three-phase currents of a, b, and c are provided. G u sim (s), G i sim (s) These are the simplified transfer functions for the voltage and current paths, respectively.

[0074] The low-order control equivalent model is obtained by simplifying the equivalent transfer function of the complete system, where the expression of the equivalent transfer function of the complete system is: In the formula, τ is the time constant. kp, k i Here, represents the PI proportional-integral parameter, s is the Laplace operator, I is the 3rd order identity matrix, and Q is the state matrix. u abc These are the three-phase voltage values ​​for phases a, b, and c. i abc,ref , i abc,ref These are the three-phase currents (A, B, and C) and their reference values, respectively. ω s For the power grid base frequency, ε For control system constants, H(s) , N(s) , M(s) This is a transfer function expression, which has no practical meaning. LThe equivalent inductance of the SVG; G u (s), G i (s) These are the complete transfer functions for the voltage and current paths, respectively.

[0075] Optionally, the formula for calculating the control equivalent voltage area is: In the formula, The commutation direction vector; Let ω be the local electrical angle and ω be the angular velocity. t For time, μ To change the phase angle, V L Γ(μ) is the fast incremental voltage vector connecting the two ends of the inductor to the SVG, and Γ(μ) is the equivalent voltage area.

[0076] Optionally, the expression for the control equivalent commutation angle calculation equation, taking into account the fast control response of SVG, is: In the formula, and These are the equivalent reactance of the converter transformer and the SVG connection reactance, respectively. This represents the effective value of the fundamental line voltage on the converter transformer side. I d Γ(μ) represents the DC current, and Γ(μ) represents the area of ​​the equivalent voltage.

[0077] Optionally, it also includes: defining the first zero-crossing angle of the SVG fast voltage in the commutation direction. When the control equivalent commutation angle is less than the first zero-crossing angle When the commutation angle is greater than or equal to the first zero-crossing angle, the commutation angle is calculated using the fast commutation angle formula; when the control equivalent commutation angle is greater than or equal to the first zero-crossing angle, the control equivalent commutation angle is used.

[0078] Optionally, it also includes: The error transfer function between the low-order control equivalent model and the equivalent transfer function of the complete system is defined. The response error is quantitatively characterized based on the induced gain and norm, and the peak frequency of the dominant error spectrum is estimated by first-order perturbation analysis. The error transfer function includes: current reference channel transfer function deviation. Deviation from the transfer function of the voltage path :

[0079] In the formula, G u (s), G i (s)These are the complete transfer functions for the voltage and current paths, respectively. G u sim (s), G i sim (s) These are the simplified transfer functions for the voltage and current paths, respectively. ΔG u (s), ΔG i (s) These are the deviation values ​​of the voltage and current path transfer functions, respectively.

[0080] The output error must meet the following requirements: in, It is the supremum of the maximum singular value; , These are the 2-norms of the three-phase current reference value and the voltage deviation, respectively; G u 、G i These are the voltage and current path transfer functions, respectively.

[0081] Optionally, the peak frequency of the dominant error spectrum is located in the power frequency and its adjacent frequency range; when the integral gain is less than a preset threshold and the modulation loop response time is less than a preset threshold, the response error of the low-order control equivalent model and the equivalent transfer function of the complete system in the frequency range adjacent to the power frequency is less than a preset tolerance.

[0082] Exemplary electronic devices Figure 8 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. For example... Figure 8 As shown, the electronic device 80 includes one or more processors 81 and memory 82.

[0083] The processor 81 may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0084] The memory 82 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 81 may execute the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above, and / or other desired functions. In one example, the electronic device may also include an input device 83 and an output device 84, these components being interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0085] In addition, the input device 83 may also include, for example, a keyboard, a mouse, etc.

[0086] The output device 84 can output various information to the outside. The output device 84 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0087] Of course, for the sake of simplicity, Figure 8 Only some of the components of this electronic device relevant to the present invention are shown, omitting components such as buses, input / output interfaces, etc. In addition, the electronic device may include any other suitable components depending on the specific application.

[0088] Exemplary computer program products and computer-readable storage media In addition to the methods and apparatus described above, embodiments of the present invention may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0089] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of the present invention. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0090] Furthermore, embodiments of the present invention may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps of the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0091] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, system, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0092] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0093] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0094] The block diagrams of devices, systems, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, systems, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0095] The methods and systems of the present invention may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of the present invention are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present invention may also be implemented as a program recorded on a recording medium, the program comprising machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers recording media storing programs for performing the methods according to the present invention.

[0096] It should also be noted that in the systems, apparatus, and methods of the present invention, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered equivalents of the present invention. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0097] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for calculating the commutation angle of a multi-source adaptive commutator converter, characterized in that, include: An equivalent circuit model for the commutation stage of SLCC is established, and the commutation circuit equations during the commutation period are determined based on the equivalent circuit diagram during the commutation period. Based on the positive sequence fundamental wave assumption, the SVG valve side voltage is used as its fundamental wave component to participate in the commutation. The commutation current equation is integrated within the commutation interval to obtain the fast commutation angle calculation formula. Based on a low-order equivalent control model of SVG control, the fast incremental voltage vector across the SVG-connected inductor is obtained within a short commutation time window. The control equivalent voltage area is obtained by projecting along the commutation direction and integrating within the commutation interval. Substituting the control equivalent voltage area into the fast commutation angle formula, we obtain the control equivalent commutation angle calculation method that takes into account the fast control response of SVG. Based on the aforementioned method for calculating the equivalent commutation angle of the control, the equivalent commutation angle of the control, taking into account the fast control response of the SVG, is calculated.

2. The method according to claim 1, characterized in that, During commutation, the voltage on the converter transformer side and the voltage on the SVG valve side are applied together to the series inductance of the commutation circuit, which together determine the transient change of the commutation current. The expression for the commutation current equation during the commutation period is: In the formula, For the voltage of line AB on the converter transformer side, , These are the A-phase voltage and B-phase voltage on the converter transformer side, respectively. The AB line voltage output by the SVG. , These are the A-phase voltage and B-phase voltage output from the SVG, respectively. L T and L S These are the commutator equivalent inductance and the SVG connection inductance, respectively. i ta , i sa These represent the currents flowing through the converter transformer and the SVG, respectively. This is the commutation current.

3. The method according to claim 1, characterized in that, Commutation start and end and Satisfying boundary conditions , For the commutation current equation in The expression for the over-integral is: The formula for calculating the fast commutation angle is: In the formula, , These are the fundamental voltages on the grid side and the SVG side, respectively. X T For converter transformer reactor, X S For SVG equivalent connection reactance, U G This refers to the grid-side voltage amplitude. U s This is the voltage at the SVG terminal. i d It is direct current. α For trigger angle, μ To change the phase angle, This represents the phase angle of the SVG voltage.

4. The method according to claim 1, characterized in that, The expression for the low-order control equivalent model is: In the formula, τ is the time constant. k p Let be the scaling factor, s be the Laplace operator, I be the 3rd order identity matrix, and Q be the state matrix. u abc These are the three-phase voltage values ​​for phases a, b, and c. i abc,ref The reference values ​​for the three-phase currents of a, b, and c are provided. G u sim (s), G i sim (s) These are the simplified transfer functions for the voltage and current paths, respectively. The low-order control equivalent model is obtained by simplifying the equivalent transfer function of the complete system, wherein the expression of the equivalent transfer function of the complete system is: In the formula, τ is the time constant. kp, k i Here, represents the PI proportional-integral parameter, s is the Laplace operator, I is the 3rd order identity matrix, and Q is the state matrix. u abc These are the three-phase voltage values ​​for phases a, b, and c. i abc,ref , i abc,ref These are the three-phase currents (A, B, and C) and their reference values, respectively. ω s For the power grid base frequency, ε For control system constants, H(s) , N(s) , M(s) This is a transfer function expression, which has no practical meaning. L The equivalent inductance of the SVG; G u (s), G i (s) These are the complete transfer functions for the voltage and current paths, respectively.

5. The method according to claim 1, characterized in that, The formula for calculating the area of ​​the control equivalent voltage is: In the formula, The commutation direction vector; Let ω be the local electrical angle and ω be the angular velocity. t For time, μ To change the phase angle, V L Γ(μ) is the fast incremental voltage vector connecting the two ends of the inductor to the SVG, and Γ(μ) is the equivalent voltage area.

6. The method according to claim 1, characterized in that, The expression for the control equivalent commutation angle calculation equation that takes into account the fast control response of SVG is: In the formula, and These are the equivalent reactance of the converter transformer and the SVG connection reactance, respectively. This represents the effective value of the fundamental line voltage on the converter transformer side. I d Γ(μ) represents the DC current, and Γ(μ) represents the area of ​​the equivalent voltage.

7. The method according to claim 6, characterized in that, Also includes: Define the first zero-crossing angle of the SVG fast voltage in the commutation direction. When the control equivalent commutation angle is less than the first zero-crossing angle When the fast commutation angle is calculated using the fast commutation angle formula, the calculated value of the fast commutation angle is used; when the control equivalent commutation angle is greater than or equal to the first zero-crossing angle, the control equivalent commutation angle is used.

8. The method according to claim 4, characterized in that, Also includes: The error transfer function between the low-order control equivalent model and the equivalent transfer function of the complete system is defined. The response error is quantitatively characterized based on the induced gain and norm, and the peak frequency of the dominant error spectrum is estimated by first-order perturbation analysis. The error transfer function includes: current reference channel transfer function deviation. Deviation from the transfer function of the voltage path : In the formula, G u (s), G i (s) These are the complete transfer functions for the voltage and current paths, respectively. G u sim (s), G i sim (s) These are the simplified transfer functions for the voltage and current paths, respectively. ΔG u (s), ΔG i (s) These are the deviation values ​​of the voltage and current path transfer functions, respectively. The output error must meet the following requirements: in, It is the supremum of the maximum singular value; , These are the 2-norms of the three-phase current reference value and the voltage deviation, respectively; G u 、G i These are the voltage and current path transfer functions, respectively.

9. The method according to claim 8, characterized in that, The peak frequency of the dominant error spectrum is located in the power frequency and its adjacent frequency range; when the integral gain is less than a preset threshold and the modulation loop response time is less than a preset threshold, the response error of the low-order control equivalent model and the equivalent transfer function of the complete system in the frequency range adjacent to the power frequency is less than a preset tolerance.

10. A commutation angle calculation device for a multi-source adaptive commutator converter, characterized in that, include: A module is established to build an equivalent circuit model for the commutation stage of SLCC. Based on the equivalent circuit diagram during commutation, the commutation circuit equations during commutation are determined. The first integration module is used to integrate the SVG valve-side voltage with its fundamental component as equivalent to participate in the commutation based on the positive sequence fundamental wave assumption, and to obtain the fast commutation angle calculation formula by integrating the commutation current equation within the commutation interval. The second integration module is used to obtain the fast incremental voltage vector across the inductor connected to the SVG within the short commutation time window, based on the low-order control equivalent model of SVG control. The control equivalent voltage area is obtained by projecting along the commutation direction and integrating within the commutation interval. The substitution module is used to substitute the control equivalent voltage area into the fast commutation angle formula to obtain the control equivalent commutation angle calculation method that takes into account the fast control response of SVG. The calculation module is used to calculate the control equivalent commutation angle, taking into account the SVG fast control response, based on the control equivalent commutation angle calculation method.

11. A computer-readable storage medium, characterized in that, The storage medium stores a computer program for performing the method described in any one of claims 1-9.

12. An electronic device, characterized in that, The electronic device includes: processor; Memory used to store the processor's executable instructions; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1-9.

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