Parameter tuning method for power synchronous grid converter considering DC voltage control

Abstract

This invention discloses a parameter tuning method for a power synchronous grid converter considering DC voltage control, comprising: calculating the range of values ​​for the DC bus capacitor; determining the DC bus capacitor setting value based on the range of values ​​for the DC bus capacitor; determining the constraint conditions for the stability of DC bus voltage control and active power synchronous control, setting the minimum damping ratio for active power synchronous control, and determining the range of values ​​for the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping based on the constraint conditions, the minimum damping ratio, and the DC bus capacitor setting value; tuning the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping based on the above value ranges, so that the DC voltage control amplitude margin is greater than or equal to a preset amplitude margin threshold and the phase margin is greater than or equal to a preset phase margin threshold.

Description

Technical Field

[0001] This invention relates to the field of power grid control technology, and more specifically, to a method and system for parameter tuning of a power synchronous grid converter that takes into account DC voltage control. Background Technology

[0002] With the rapid development of new energy sources, power electronic converters have initially achieved large-scale grid connection. Extensive theoretical research and practical experience have shown that converters based on phase-locked loop (PLL) synchronization are prone to stability issues such as wide-frequency oscillations under weak grid conditions, and lack the support function for grid frequency and voltage, thus weakening the safe and stable operation capability of large power grids. To improve the grid-connection adaptability of converters under weak grid conditions and enable them to possess voltage and frequency support functions similar to synchronous generators, relevant scholars have proposed control strategies for grid-connected converters based on active power synchronization (hereinafter referred to as power synchronous converters), mainly including two types: virtual synchronization control and droop control.

[0003] When an ideal energy source is absent on the DC side, power synchronous grid converters need to autonomously regulate the DC bus voltage, typically employing a cascaded control structure of an outer DC voltage loop and an inner active power synchronization loop. However, both the active power synchronization loop and the DC voltage loop participate in active power regulation after disturbances, leading to mutual interference and potential converter instability. Therefore, the electrical and control parameters of the converter have a significant impact on ensuring its stable grid-connected operation.

[0004] Currently, there are no reports on the quantitative indicators of internal potential intensity in the initial stage of a fault in a power synchronous grid converter. Furthermore, most studies on power synchronous grid converters assume a constant DC side (i.e., a constant energy source on the DC side), lacking standardized methods for designing DC side parameters. Additionally, both the active power synchronization loop and the DC voltage loop participate in active power regulation after disturbances, and their interaction after fault disturbances can easily lead to converter instability; however, effective parameter tuning methods are currently lacking.

[0005] Therefore, there is a need for a method for tuning the electrical and control parameters of a power synchronous grid converter that takes into account the coupling effect of DC voltage control and active power synchronization control and can avoid instability. Summary of the Invention

[0006] This invention proposes a parameter tuning method and system for a power synchronous grid converter that takes into account DC voltage control, in order to solve the problem of how to achieve stable control of the power synchronous grid converter after disturbance.

[0007] To address the aforementioned problems, according to one aspect of the present invention, a method for parameter tuning of a power synchronous grid converter considering DC voltage control is provided, the method comprising:

[0008] Based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter, calculate the range of values ​​for the DC bus capacitor.

[0009] The DC bus capacitor setting value is determined based on the range of DC bus capacitor values.

[0010] Determine the constraints for the stability of DC bus voltage control and active power synchronization control, set the minimum damping ratio for active power synchronization control, and based on the constraints, the minimum damping ratio, and the DC bus capacitor setting value, determine the range of values ​​for the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping.

[0011] Based on the range of values ​​for the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping, the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping are tuned so that the DC voltage control amplitude margin is greater than or equal to the preset amplitude margin threshold and the phase margin is greater than or equal to the preset phase margin threshold.

[0012] Preferably, the range of values ​​for the DC bus capacitor is calculated based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter, including:

[0013] ,

[0014] Among them, C dc For DC bus capacitance; K is from 0 to T max The multiple of the unit active power imbalance borne by the converter within a time period; T max S is the maximum time required for the DC voltage to decrease from its rated value to the protection threshold. b This refers to the rated capacity of a power synchronous grid converter. For protection threshold; U dc,0 This is the rated DC voltage of the power synchronous grid converter.

[0015] Preferably, the constraints include:

[0016] ,

[0017] ,

[0018] ,

[0019] ,

[0020] in, k pdc This is the DC voltage PI proportional coefficient; ω idc C is the integral coefficient of the DC voltage PI. dc D is the DC bus capacitance; D is the virtual damping; T J For virtual inertia parameters; ω 0 is the rated angular frequency; K C For constant terms, xt is the connection impedance between the converter's internal potential and the main grid; ζ min K is the minimum damping ratio for active power synchronous control. dc These are preset coefficients; P ac,0 U represents the steady-state value of active power during converter operation. dc,0 This is the rated DC voltage of the power synchronous grid converter.

[0021] Preferably, the preset amplitude margin threshold is 2, and the phase margin threshold is 30°.

[0022] According to another aspect of the present invention, a parameter tuning system for a power synchronous grid converter considering DC voltage control is provided, the system comprising:

[0023] The DC bus capacitance calculation unit is used to calculate the range of DC bus capacitance values ​​based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter.

[0024] The first parameter tuning unit is used to determine the DC bus capacitor tuning value based on the range of DC bus capacitor values.

[0025] The parameter value range determination unit is used to determine the constraints for the stability of DC bus voltage control and active power synchronization control, set the minimum damping ratio for active power synchronization control, and, based on the constraints, the minimum damping ratio and the DC bus capacitor setting value, determine the value range of the DC voltage PI proportional coefficient, the value range of the DC voltage PI integral coefficient, the value range of the virtual inertia time constant and the value range of the virtual damping.

[0026] The second parameter tuning unit is used to tune the DC voltage PI proportional coefficient, DC voltage PI integral coefficient, virtual inertia time constant, and virtual damping based on the range of values ​​of the DC voltage PI proportional coefficient, the range of values ​​of the DC voltage PI integral coefficient, the range of values ​​of the virtual inertia time constant, and the range of values ​​of the virtual damping, so that the DC voltage control amplitude margin is greater than or equal to the preset amplitude margin threshold and the phase margin is greater than or equal to the preset phase margin threshold.

[0027] Preferably, the DC bus capacitance calculation unit calculates the range of DC bus capacitance values ​​based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter, including:

[0028] ,

[0029] Among them, C dc For DC bus capacitance; K is from 0 to T max The multiple of the unit active power imbalance borne by the converter within a time period; T max S is the maximum time required for the DC voltage to decrease from its rated value to the protection threshold. b This refers to the rated capacity of a power synchronous grid converter. For protection threshold; U dc,0 This is the rated DC voltage of the power synchronous grid converter.

[0030] Preferably, the constraints include:

[0031] ,

[0032] ,

[0033] ,

[0034] ,

[0035] in, k pdc This is the DC voltage PI proportional coefficient; ω idc C is the integral coefficient of the DC voltage PI. dc D is the DC bus capacitance; D is the virtual damping; T J For virtual inertia parameters; ω 0 is the rated angular frequency; K C For constant terms, xt is the connection impedance between the converter's internal potential and the main grid; ζ minK is the minimum damping ratio for active power synchronous control. dc These are preset coefficients; P ac,0 U represents the steady-state value of active power during converter operation. dc,0 This is the rated DC voltage of the power synchronous grid converter.

[0036] Preferably, the preset amplitude margin threshold is 2, and the phase margin threshold is 30°.

[0037] According to another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the methods for parameter tuning of a power synchronous grid converter taking into account DC voltage control.

[0038] According to another aspect of the present invention, the present invention provides an electronic device, comprising:

[0039] The aforementioned computer-readable storage medium; and

[0040] One or more processors for executing a program in the computer-readable storage medium.

[0041] This invention provides a method and system for parameter tuning of a power synchronous grid converter considering DC voltage control, comprising: calculating the range of DC bus capacitor values ​​based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter; determining the DC bus capacitor setting value based on the range of DC bus capacitor values; determining the constraints for the stability of DC bus voltage control and active power synchronous control, setting the minimum damping ratio for active power synchronous control, and determining the DC bus capacitor setting value based on the constraints, the minimum damping ratio, and the DC bus capacitor setting value. The method defines the value ranges of the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping. Based on these ranges, the DC voltage PI proportional coefficient, DC voltage PI integral coefficient, virtual inertia time constant, and virtual damping are tuned to ensure that the DC voltage control amplitude margin is greater than or equal to a preset amplitude margin threshold and the phase margin is greater than or equal to a preset phase margin threshold. This method, by tuning the electrical and control parameters of the power synchronous grid converter, can effectively improve the internal potential intensity of the converter within 1-2 cycles of grid disturbance (i.e., the initial stage of a fault). Simultaneously, it can ensure the stability of active power synchronization control and DC voltage control during small disturbances 1-2 cycles after the disturbance occurs (during the fault and during post-fault recovery). Attached Figure Description

[0042] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0043] Figure 1 A flowchart of a power synchronous grid converter parameter tuning method 100 considering DC voltage control according to an embodiment of the present invention;

[0044] Figure 2 This is a cascaded control structure diagram of DC voltage control and active power synchronization control according to an embodiment of the present invention;

[0045] Figure 3 This is a circuit structure diagram of a power synchronous grid converter according to an embodiment of the present invention;

[0046] Figure 4 The simulation results using conventional DC-side parameters are shown in the figure.

[0047] Figure 5 This is a simulation result diagram of the grid connection point voltage according to an embodiment of the present invention;

[0048] Figure 6 Nyquist curves for D=15 p.u. and D=62 p.u. under weak power grid conditions;

[0049] Figure 7 The figure shows the simulation results of the DC bus voltage according to an embodiment of the present invention.

[0050] Figure 8 This is a schematic diagram of the structure of a power synchronous grid converter parameter tuning system 800 that takes into account DC voltage control according to an embodiment of the present invention. Detailed Implementation

[0051] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0052] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0053] The method of this invention can be used for assessing the voltage support capability during the initial fault stage, designing DC parameters, and setting parameters for active power synchronization control and DC voltage control of various power synchronous grid converters (such as wind power, photovoltaic, SVG, etc.) without a constant energy source on the DC side.

[0054] Figure 1 This is a flowchart of a power synchronous grid converter parameter tuning method 100 considering DC voltage control according to an embodiment of the present invention. Figure 1 As shown, the parameter tuning method for a power synchronous grid converter considering DC voltage control provided by this invention can effectively improve the internal potential intensity of the converter within 1-2 cycles of a grid disturbance (i.e., the initial stage of a fault) by tuning the electrical and control parameters of the power synchronous grid converter. Simultaneously, it can ensure the stability of active power synchronization control and DC voltage control during small disturbances 1-2 cycles after the disturbance occurs (during the fault and during post-fault recovery). The parameter tuning method 100 for a power synchronous grid converter considering DC voltage control provided by this invention starts from step 101. In step 101, based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter, the range of values ​​for the DC bus capacitor is calculated.

[0055] Preferably, the range of values ​​for the DC bus capacitor is calculated based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter, including:

[0056] ,

[0057] Among them, C dc For DC bus capacitance; K is from 0 to T max The multiple of the unit active power imbalance borne by the converter within a time period; T max S is the maximum time required for the DC voltage to decrease from its rated value to the protection threshold. b This refers to the rated capacity of a power synchronous grid converter. For protection threshold; U dc,0 This is the rated DC voltage of the power synchronous grid converter.

[0058] In step 102, the DC bus capacitor setting value is determined based on the range of DC bus capacitor values.

[0059] The equivalent circuit of a power synchronous grid converter consists of a controlled voltage source and an impedance. Z Series connection. The potential of the controlled voltage source. E This refers to the internal potential of a power synchronous grid converter, expressed as:

[0060] (1)

[0061] in, U dc This is the actual value of the DC bus voltage; m Converter modulation signal amplitude, ω GFM The internal potential angular frequency is denoted as ω.

[0062] The internal potential intensity of a power synchronous grid converter refers to the internal potential maintained during a short circuit in the external system. E Amplitude U dc × m and frequency ω GFM Approximately constant capability. Derived from the converter grid-connected node voltage expression. V = Ej×I×Z ( I Given the converter output current, it can be seen that the internal potential is guaranteed. E Strength is one of the prerequisites for supporting the voltage of a system.

[0063] Within 1-2 cycles of the fault occurrence, the voltage regulator and synchronization circuit have not yet started responding, and can be approximately considered as follows: m and ω GFM The voltage remains approximately constant. However, due to the phase jump during line switching, a natural surge in active power occurs, leading to energy imbalance on the DC bus and affecting the actual DC voltage value. U dc There is a risk of a significant reduction, as can be seen from the formula above. U dc × m It becomes difficult to maintain a constant voltage, leading to a decrease in the internal potential intensity of power synchronous grid converters. Therefore, in the early stages of a fault, it is necessary to avoid this through DC-side parameter design. U dc There is a problem of significant reduction.

[0064] DC bus voltage U dc The mathematical model is as follows:

[0065] (2)

[0066] in, C dc P represents the DC bus capacitance. ac This refers to the active power on the AC side of the power synchronous grid converter.

[0067] Quantifying formula (2) yields:

[0068] (3)

[0069] Among them, superscript This represents the quantified value of the variable. S b The rated capacity of the power synchronous grid converter, U dc,0 This is the rated voltage of the DC bus of the converter (which can be selected and set according to the expected operating targets).

[0070] make , in formula (3), 0.5×C dc ×U 2 dc,0 The unit is joule (watt × second). S b The unit is megawatt. According to dimensional analysis, the quantized value of DC capacitance is... The unit is seconds, that is: the active power imbalance in unit (1.pu). Under the action of the DC bus voltage, the time taken for the DC bus voltage to decrease from the rated value to 0 is That is, internal potential E The time it takes for the amplitude to drop to 0. Therefore, we can use... As a quantitative indicator of the internal potential intensity of a power synchronous grid converter in the early stage of a fault, its unit is seconds.

[0071] To ensure response in the voltage regulator and synchronization circuit, the power synchronous grid converter can maintain stable internal potential by reducing the DC voltage from the rated value of 1.pu to the protection threshold. The maximum time used is T max We can obtain:

[0072] (4)

[0073] in, K Indicates that the phase jump leads to K The unit of multiple (1.pu) represents the active power imbalance. Impact.

[0074] exist T max Within a given time period, the DC voltage of the power synchronous grid converter can remain above the protection threshold. This allows the DC voltage to be restored after the controller (voltage regulator and synchronization circuit) operates, maintaining a stable internal potential, thus increasing the internal potential strength (for this reason, T max The general setting is: the time taken from the occurrence of a fault to the start-up of the controller (voltage regulator and synchronization link), plus a delay to ensure sufficient margin.

[0075] Furthermore, by converting formula (4) into named values, the design range of DC-side parameters for improving the internal potential intensity during the initial stage of a fault in a power synchronous grid converter can be obtained as follows:

[0076] (5)

[0077] in, C dc The unit is farad (F). T max The unit is seconds (s). S b The unit is watts. U dc,0 The unit is volts.

[0078] Therefore, in this invention, the range of DC bus capacitor values ​​is determined based on formula (5), and the DC bus capacitor is adjusted according to requirements within the range of DC bus capacitor values ​​to determine the DC bus capacitor setting value.

[0079] In step 103, the constraints for the stability of DC bus voltage control and active power synchronization control are determined, the minimum damping ratio of active power synchronization control is set, and based on the constraints, the minimum damping ratio and the DC bus capacitor setting value, the range of values ​​for the DC voltage PI proportional coefficient, the range of values ​​for the DC voltage PI integral coefficient, the range of values ​​for the virtual inertia time constant and the range of values ​​for the virtual damping are determined.

[0080] In step 104, the DC voltage PI proportional coefficient, DC voltage PI integral coefficient, virtual inertia time constant, and virtual damping are tuned based on the range of values ​​of the DC voltage PI proportional coefficient, the range of values ​​of the DC voltage PI integral coefficient, the range of values ​​of the virtual inertia time constant, and the range of values ​​of the virtual damping, so that the DC voltage control amplitude margin is greater than or equal to the preset amplitude margin threshold and the phase margin is greater than or equal to the preset phase margin threshold.

[0081] Preferably, the constraints include:

[0082] ,

[0083] ,

[0084] ,

[0085] ,

[0086] in, k pdc This is the DC voltage PI proportional coefficient; ωidc C is the integral coefficient of the DC voltage PI. dc D is the DC bus capacitance; D is the virtual damping; T J For virtual inertia parameters; ω 0 is the rated angular frequency; K C For constant terms, xt is the connection impedance between the converter's internal potential and the main grid; ζ min K is the minimum damping ratio for active power synchronous control. dc These are preset coefficients; P ac,0 U represents the steady-state value of active power during converter operation. dc,0 This is the rated DC voltage of the power synchronous grid converter.

[0087] Preferably, the preset amplitude margin threshold is 2, and the phase margin threshold is 30°.

[0088] Combination Figure 2 As shown, the power synchronous converter adopts a cascaded control structure of DC voltage outer loop and active power synchronization inner loop. To achieve flexible setting of the minimum damping ratio for active power synchronization control, DC voltage control amplitude margin gm ≥ 2, and phase margin pm ≥ 30°, the following four sets of inequalities must be satisfied:

[0089] (6)

[0090] (7)

[0091] (8)

[0092] (9)

[0093] in, k pdc This is the DC voltage PI proportional coefficient; ω idc C is the integral coefficient of the DC voltage PI. dc D is the DC bus capacitance; D is the virtual damping; T J For virtual inertia parameters; ω 0 is the rated angular frequency. ω 0 = 100π; K C For constant terms; ζ min This is the minimum damping ratio for active power synchronization control, which can be set according to the damping requirements of the converter's active power synchronization control, generally based on ζmin > 0.5; K dc These are preset coefficients, generally based on K. dcValues ​​≥5; P ac,0 This refers to the steady-state active power value during converter operation, which can be set according to the expected operating targets; U dc,0 This is the rated DC voltage of the power synchronous grid converter.

[0094] Through the above constraints, the DC voltage control amplitude margin gm≥2 can be achieved, the minimum damping ratio of active power synchronous control can be flexibly set, and the DC voltage control phase margin pm≥30° can be achieved. Among them, when formula (6) is satisfied, the DC voltage control amplitude margin gm≥2 can be achieved. The left half of the inequality shown in formula (8) corresponds to the flexible setting of the minimum damping ratio; the right half of the inequality shown in formula (8) ensures that the negative damping generated by the active power synchronous control damping ratio improvement process on the DC voltage control can be ignored; formula (7) ensures that the phase lag effect generated by the integral link and the active power synchronous control link in the DC voltage PI controller can be approximately ignored; formula (9) ensures that the phase lag effect generated by the non-minimum phase dynamics in the DC bus model can be ignored.

[0095] Therefore, in this invention, firstly, a minimum damping ratio is set; then, the ranges of the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping are determined; then, based on the ranges of the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping, the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping are tuned so that the DC voltage control amplitude margin gm≥2 and the phase margin pm≥30°.

[0096] To verify the effectiveness of the proposed parameter design method, based on Figure 3 The system architecture was simulated using the MATLAB / Simulink platform. The converter capacity is 0.5MW, the rated DC voltage is 1000V, and the control system employs a loopless control structure. The synchronization element uses power synchronization control, and the voltage regulator uses a constant voltage control mode. t=5 s A three-phase ground fault occurred, with a grounding resistance of 0.008Ω and a duration of 0.1 seconds. s .

[0097] Referring to the selection scheme of DC capacitors for conventional grid-type converters, a 50mF DC capacitor is configured. Calculations using formula (3) show that... =0.05, that is: the active power imbalance per unit (1.pu). Under the influence of [the current], the DC bus voltage decreased from its rated value to 0 in 0.05 seconds. This indicates that the internal potential strength of the synchronous power grid converter was relatively weak during the initial stage of a fault. Figure 4 Simulation results are presented, showing that the grid connection point voltage continues to decrease after the fault occurs, indicating that the power synchronous grid converter is unable to provide effective voltage support to the system.

[0098] The maximum time required for the DC voltage to decrease from the rated value of 1.pu to the protection threshold of 0.8pu is set as follows. T max =0.05s, which means that the power synchronous grid converter has a stable DC voltage before the controller responds (in the early stage of the fault). Considering that the maximum active instantaneous impact caused by the phase jump is 3 times the rated current (power synchronous grid converters are generally required to have 3 times the overcurrent capacity), it can be seen from formula (5) that C dc It should be greater than 750mF. Figure 5 Simulation results are presented, showing that the grid connection voltage remains basically stable after the fault occurs, verifying the effectiveness of the method.

[0099] Based on DC capacitor C dc It should be greater than 750mF, so select Cdc=1000mF and short-circuit ratio SCR=1 / x t Under the condition that X = 1.667, t =Xt1+Xt21+Xt22, the converter is required to stably output 0.95pu of active power. According to the above requirements, the DC voltage loop and active synchronization loop parameter settings are calculated using formulas (6), (7), (8) and (9), and the results are shown in Table 1.

[0100] Table 1. Parameter tuning results of power synchronous converters that meet the requirements for operation in weak power grids.

[0101]

[0102] Based on the parameters in Table 1, take D =22p.u. and take D =62p.u., calculate the Nyquist plot of the open-loop transfer function of the power synchronous converter, and the results are as follows: Figure 6 As shown. From Figure 6 It can be seen that when D When the value is 22p.u., the system has a gain margin g. m ≥2 and phase margin m =47.5°. When taking D When the value of 62p.u. exceeds the upper limit of the virtual damping parameter calculated in Table 1, it can be seen that the phase margin of the system is... m =13°, no longer meets the phase margin requirement. m Design requirement of ≥30°.

[0103] Using the same parameters, simulation analysis was performed using a nonlinear electromagnetic transient model. The reference value of the controlled current source on the DC side was varied during the simulation. I dc Adjusting the injected DC power P dc =U dc I dc The result of a step change from 0 p.u. to 0.95 p.u. and then a step change back to 0 p.u. is as follows. Figure 7 As shown. From Figure 7 It can be seen that when D When = 22p.u., the system's time-domain response waveform has only a slight overshoot. When D When the value is 62p.u., the time-domain response waveform of the system exhibits a weakly damped oscillatory component. Figure 7 The time-domain simulation results shown are consistent with Figure 6 The results of the Nyquist analysis were consistent, verifying the effectiveness of the parameter tuning formulas (6), (7), (8) and (9).

[0104] This is a schematic diagram of the parameter tuning system 800 for a power synchronous grid converter considering DC voltage control according to an embodiment of the present invention. Figure 8 As shown, the power synchronous grid converter parameter tuning system 800 considering DC voltage control provided in this embodiment of the invention includes: a DC bus capacitor calculation unit 801, a first parameter tuning unit 802, a parameter value range determination unit 803, and a second parameter tuning unit 804.

[0105] Preferably, the DC bus capacitance calculation unit 801 is used to calculate the range of DC bus capacitance values ​​based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter.

[0106] Preferably, the DC bus capacitance calculation unit 801 calculates the range of DC bus capacitance values ​​based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter, including:

[0107] ,

[0108] Among them, C dc For DC bus capacitance; K is from 0 to T max The multiple of the unit active power imbalance borne by the converter within a time period; Tmax S is the maximum time required for the DC voltage to decrease from its rated value to the protection threshold. b This refers to the rated capacity of a power synchronous grid converter. For protection threshold; U dc,0 This is the rated DC voltage of the power synchronous grid converter.

[0109] Preferably, the first parameter tuning unit 802 is used to determine the DC bus capacitor tuning value based on the range of DC bus capacitor values.

[0110] Preferably, the parameter value range determination unit 803 is used to determine the constraint conditions for the stability of DC bus voltage control and active power synchronization control, set the minimum damping ratio of active power synchronization control, and determine the value range of DC voltage PI proportional coefficient, DC voltage PI integral coefficient, virtual inertia time constant and virtual damping based on the constraint conditions, minimum damping ratio and DC bus capacitor setting value.

[0111] Preferably, the constraints include:

[0112] ,

[0113] ,

[0114] ,

[0115] ,

[0116] in, k pdc This is the DC voltage PI proportional coefficient; ω idc C is the integral coefficient of the DC voltage PI. dc D is the DC bus capacitance; D is the virtual damping; T J For virtual inertia parameters; ω 0 is the rated angular frequency; K C For constant terms, xt is the connection impedance between the converter's internal potential and the main grid; ζ min K is the minimum damping ratio for active power synchronous control. dc These are preset coefficients; P ac,0 U represents the steady-state value of active power during converter operation. dc,0 This is the rated DC voltage of the power synchronous grid converter.

[0117] Preferably, the second parameter tuning unit 804 is used to tune the DC voltage PI proportional coefficient, DC voltage PI integral coefficient, virtual inertia time constant, and virtual damping based on the value range of the DC voltage PI proportional coefficient, the value range of the DC voltage PI integral coefficient, the value range of the virtual inertia time constant, and the value range of the virtual damping, so that the DC voltage control amplitude margin is greater than or equal to a preset amplitude margin threshold and the phase margin is greater than or equal to a preset phase margin threshold.

[0118] Preferably, the preset amplitude margin threshold is 2, and the phase margin threshold is 30°.

[0119] The power synchronous grid converter parameter tuning system 800 considering DC voltage control in an embodiment of the present invention corresponds to the power synchronous grid converter parameter tuning method 100 considering DC voltage control in another embodiment of the present invention, and will not be described again here.

[0120] According to another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the methods for parameter tuning of a power synchronous grid converter taking into account DC voltage control.

[0121] According to another aspect of the present invention, the present invention provides an electronic device, comprising:

[0122] The aforementioned computer-readable storage medium; and

[0123] One or more processors for executing a program in the computer-readable storage medium.

[0124] The present invention has been described with reference to a few embodiments. However, it will be apparent to those skilled in the art that other embodiments besides those disclosed above fall equivalently within the scope of the present invention.

[0125] Generally, all terms used in this invention are interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0126] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0127] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0128] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0129] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the functions specified in one or more boxes. Those skilled in the art should understand that modifications or other variations can still be made to the specific embodiments of the present invention.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for parameter tuning of a power synchronous grid converter considering DC voltage control, characterized in that, The method includes: Based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter, calculate the range of values ​​for the DC bus capacitor. The DC bus capacitor setting value is determined based on the range of DC bus capacitor values. Determine the constraints for the stability of DC bus voltage control and active power synchronization control, set the minimum damping ratio for active power synchronization control, and based on the constraints, the minimum damping ratio, and the DC bus capacitor setting value, determine the range of values ​​for the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping. Based on the range of values ​​for the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping, the DC voltage PI proportional coefficient, the DC voltage PI integral coefficient, the virtual inertia time constant, and the virtual damping are tuned so that the DC voltage control amplitude margin is greater than or equal to the preset amplitude margin threshold and the phase margin is greater than or equal to the preset phase margin threshold. Among them, based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter, the range of values ​​for the DC bus capacitor is calculated, including: ， Among them, C dc For DC bus capacitance; K is from 0 to T max The multiple of the unit active power imbalance borne by the converter within a time period; T max S is the maximum time required for the DC voltage to decrease from its rated value to the protection threshold. b The rated capacity of the power synchronous grid converter; U * dc,min For protection threshold; U dc,0 This is the rated DC voltage of the power synchronous grid converter; The constraints include: ， ， ， ， in, k pdc This is the DC voltage PI proportional coefficient; ω idc C is the integral coefficient of the DC voltage PI. dc D is the DC bus capacitance; D is the virtual damping; T J For virtual inertia parameters; ω 0 is the rated angular frequency; K C For constant terms, K C =1 / x t xt is the connection impedance between the converter's internal potential and the main grid; ζ min K is the minimum damping ratio for active power synchronous control. dc These are preset coefficients; P ac,0 U represents the steady-state value of active power during converter operation. dc,0 This is the rated DC voltage of the power synchronous grid converter.

2. The method according to claim 1, characterized in that, The preset amplitude margin threshold is 2, and the phase margin threshold is 30°.

3. A parameter tuning system for a power synchronous grid converter considering DC voltage control, characterized in that, The system includes: The DC bus capacitance calculation unit is used to calculate the range of DC bus capacitance values ​​based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter. The first parameter tuning unit is used to determine the DC bus capacitor tuning value based on the range of DC bus capacitor values. The parameter value range determination unit is used to determine the constraints for the stability of DC bus voltage control and active power synchronization control, set the minimum damping ratio for active power synchronization control, and, based on the constraints, the minimum damping ratio and the DC bus capacitor setting value, determine the value range of the DC voltage PI proportional coefficient, the value range of the DC voltage PI integral coefficient, the value range of the virtual inertia time constant and the value range of the virtual damping. The second parameter tuning unit is used to tune the DC voltage PI proportional coefficient, DC voltage PI integral coefficient, virtual inertia time constant, and virtual damping based on the range of values ​​of the DC voltage PI proportional coefficient, the range of values ​​of the DC voltage PI integral coefficient, the range of values ​​of the virtual inertia time constant, and the range of values ​​of the virtual damping, so that the DC voltage control amplitude margin is greater than or equal to the preset amplitude margin threshold and the phase margin is greater than or equal to the preset phase margin threshold. The DC bus capacitance calculation unit calculates the range of DC bus capacitance values ​​based on the rated DC voltage, rated capacity, protection threshold, and the maximum time required for the DC voltage to decrease from the rated value to the protection threshold of the power synchronous grid converter. This range includes: ， Among them, C dc For DC bus capacitance; K is from 0 to T max The multiple of the unit active power imbalance borne by the converter within a time period; T max S is the maximum time required for the DC voltage to decrease from its rated value to the protection threshold. b The rated capacity of the power synchronous grid converter; U * dc,min For protection threshold; U dc,0 This is the rated DC voltage of the power synchronous grid converter; The constraints include: ， ， ， ， in, k pdc This is the DC voltage PI proportional coefficient; ω idc C is the integral coefficient of the DC voltage PI. dc D is the DC bus capacitance; D is the virtual damping; T J For virtual inertia parameters; ω 0 is the rated angular frequency; K C For constant terms, K C =1 / x t xt is the connection impedance between the converter's internal potential and the main grid; ζ min K is the minimum damping ratio for active power synchronous control. dc These are preset coefficients; P ac,0 U represents the steady-state value of active power during converter operation. dc,0 This is the rated DC voltage of the power synchronous grid converter.

4. The system according to claim 3, characterized in that, The preset amplitude margin threshold is 2, and the phase margin threshold is 30°.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method as described in any one of claims 1-2.

6. An electronic device, characterized in that, include: The computer-readable storage medium as described in claim 5; as well as One or more processors for executing a program in the computer-readable storage medium.

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