Network construction type new energy fault ride-through method and system for realizing amplitude-phase stability

Abstract

The invention discloses a grid construction type new energy fault ride-through method and system for realizing amplitude-phase stability, and the method comprises the steps: obtaining a power grid voltage amplitude and a deviation phase angle relative to the steady-state power grid voltage based on the power grid voltage after the fault when a power grid breaks down; performing power setting based on a power angle of the system in a steady state, the power grid voltage amplitude and the deviation phase angle to obtain an active power reference value and a reactive power reference value; and performing network construction type control based on the active power reference value and the reactive power reference value to realize fault ride-through. According to the fault ride-through method, the fault ride-through of the network construction type new energy can be realized only by adjusting the power reference value of the control link, only the control link needs to be added at the network construction type control front end, the change of the original network construction control link is reduced, the realization difficulty is low, and the fault ride-through strategy does not need to add a current loop in the network construction type control link, so that the fault ride-through efficiency is improved. Compared with the traditional fault ride-through control based on current, the control response speed and stability of the network construction type new energy are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy grid-connected control, and more specifically, to a method and system for realizing fault ride-through of network-forming new energy with amplitude-phase stability. Background Art

[0002] Traditional new energy adopts a grid-following control strategy. The external characteristics of grid-following new energy present a current-source characteristic (controlling grid-connected current), but the inertia and damping characteristics of grid-following new energy are poor, resulting in insufficient inertia of the power grid. In order to improve the inertia support ability of new energy for the power grid, the current solution is to adopt a network-forming control strategy to realize new energy grid connection. The external characteristics of network-forming new energy present a voltage-source characteristic (controlling grid-connected voltage).

[0003] During a power grid fault, the fault current of new energy grid connection increases extremely. Since new energy is grid-connected based on a power electronic converter and has poor over-current tolerance, it is easy to cause new energy to trip off the grid during a fault, and even cause damage to grid-connected equipment. However, the new energy grid connection guidelines require that new energy does not trip off the grid and continues to operate within a certain voltage dip level and time, and has a certain fault ride-through ability. And because it is difficult to control the grid-connected current of network-forming new energy, the fault ride-through control is relatively difficult.

[0004] The current fault ride-through strategy for network-forming new energy is to add a current control link to the inner loop of the network-forming control, and realize fault ride-through through current limiting or constant current control. However, this fault ride-through method first requires the transformation of the network-forming control link, thereby introducing control delay and reducing the stability of the control system. Secondly, the forced current limiting control strategy reduces the power angle stability of network-forming new energy, and the constant current control strategy is essentially a grid-following control strategy, resulting in the inability of network-forming new energy to support the operation of the power grid during a fault.

[0005] Therefore, a method and system for realizing fault ride-through of network-forming new energy with amplitude-phase stability are needed. Summary of the Invention

[0006] The present invention proposes a method and system for realizing fault ride-through of network-forming new energy with amplitude-phase stability to solve the problem of how to efficiently realize fault ride-through of network-forming new energy.

[0007] To solve the above problems, according to one aspect of the present invention, a method for realizing fault ride-through of network-forming new energy with amplitude-phase stability is provided, and the method includes:

[0008] When a power grid fault occurs, obtain the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the post-fault grid voltage;

[0009] Based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle, perform power setting to obtain the active power reference value and the reactive power reference value;

[0010] Based on the active power reference value and the reactive power reference value, perform grid-forming control to achieve fault ride-through.

[0011] Preferably, the obtaining the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the grid voltage after a fault includes:

[0012] Based on the grid voltage after a fault, obtain the grid voltage amplitude through amplitude extraction, and obtain the deviation phase angle relative to the steady-state grid voltage through a phase-locked loop (PLL).

[0013] Preferably, the performing power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle to obtain the active power reference value and the reactive power reference value includes:

[0014]

[0015] Where P c is the active power reference value, k is the grid strength, |U g | is the grid voltage amplitude after a fault, δ is the power angle of the system under steady state, α is the deviation phase angle, Q c is the reactive power reference value, and ρ is the resistance-inductance ratio.

[0016] Preferably, the method further includes:

[0017] When the grid has no fault, determine the active power reference value and the reactive power reference value based on the maximum power point tracking (MPPT) of new energy under steady state, and perform grid-forming control.

[0018] According to another aspect of the present invention, there is provided a grid-forming new energy fault ride-through system for realizing amplitude-phase stability, the system including:

[0019] A voltage amplitude and deviation phase angle obtaining unit, configured to obtain the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the grid voltage after a fault when the grid has a fault;

[0020] An active and reactive power reference value obtaining unit, configured to perform power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle to obtain the active power reference value and the reactive power reference value;

[0021] A control unit, configured to perform grid-forming control based on the active power reference value and the reactive power reference value to achieve fault ride-through.

[0022] Preferably, the voltage amplitude and deviation phase angle acquisition unit obtains the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the post-fault grid voltage, and includes:

[0023] Based on the post-fault grid voltage, the grid voltage amplitude is obtained through amplitude extraction, and the deviation phase angle relative to the steady-state grid voltage is obtained through a phase-locked loop (PLL).

[0024] Preferably, the active and reactive power reference value acquisition unit performs power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle to obtain the active power reference value and the reactive power reference value, and includes:

[0025]

[0026] Wherein, P c is the active power reference value, k is the grid strength, |U g | is the post-fault grid voltage amplitude, δ is the power angle of the system under steady state, α is the deviation phase angle, Q c is the reactive power reference value, and ρ is the resistance-inductance ratio.

[0027] Preferably, the control unit further includes:

[0028] When no fault occurs in the grid, the active power reference value and the reactive power reference value are determined based on the maximum power point tracking (MPPT) of new energy under steady state, and grid-forming control is performed.

[0029] On the other hand of the present invention, the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of any one of the grid-forming new energy fault ride-through methods for achieving amplitude-phase stability are implemented.

[0030] On the other hand of the present invention, the present invention provides an electronic device, including:

[0031] The above-mentioned computer-readable storage medium; and

[0032] One or more processors for executing the program in the computer-readable storage medium.

[0033] The present invention provides a method and system for grid-forming new energy fault ride-through to achieve amplitude-phase stability, including: when a grid fault occurs, obtaining the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the post-fault grid voltage; performing power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle to obtain the reference value of active power and the reference value of reactive power; performing grid-forming control based on the reference values of active power and reactive power to achieve fault ride-through. The method of the present invention can achieve the fault ride-through of grid-forming new energy only by adjusting the power reference value of the control link, only need to add a control link at the front end of the grid-forming control, reduce the modification of the original grid-forming control link, with low implementation difficulty, and this fault ride-through strategy does not need to add a current loop in the grid-forming control link. Compared with the traditional current-based fault ride-through control, it improves the control response speed and stability of grid-forming new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The exemplary embodiments of the present invention can be more fully understood by referring to the following drawings:

[0035] Figure 1 FIG. 100 is a flowchart of a method for grid-forming new energy fault ride-through to achieve amplitude-phase stability according to an embodiment of the present invention;

[0036] Figure 2 FIG. 113 is a schematic diagram of a grid-forming converter connected to the grid according to an embodiment of the present invention;

[0037] Figure 3 FIG. 117 is a schematic diagram of a basic vector diagram and coordinate decomposition according to an embodiment of the present invention;

[0038] Figure 4 FIG. 121 is a trajectory diagram of the end point of the Us vector according to an embodiment of the present invention;

[0039] Figure 5 FIG. 125 is a distribution diagram of active and reactive power trajectories under different values of the resistance-inductance ratio according to an embodiment of the present invention;

[0040] Figure 6 FIG. 129 is a steady-state vector diagram of the grid-connected system according to an embodiment of the present invention;

[0041] Figure 7 FIG. 133 is a schematic diagram of the control link according to an embodiment of the present invention;

[0042] Figure 8 FIG. 137 is a flowchart of the control link according to an embodiment of the present invention;

[0043] Figure 9 FIG. 139 is a vector diagram of the grid-connected system during a fault according to an embodiment of the present invention;

[0044] Figure 10Schematic diagram of a network - forming new - energy fault - ride - through system 1000 for achieving amplitude - phase stability according to an embodiment of the present invention. Detailed implementation manners

[0045] Now, exemplary embodiments of the present invention will be introduced with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely, and to fully convey the scope of the present invention to those skilled in the art. The terms in the exemplary embodiments shown in the drawings are not limitations on the present invention. In the drawings, the same unit / element uses the same reference numeral.

[0046] Unless otherwise specified, the terms (including scientific and technical terms) used herein have the ordinary meaning understood by those skilled in the art. Additionally, it can be understood that terms defined in a commonly used dictionary should be understood to have a meaning consistent with the context of their related fields, and should not be understood in an idealized or overly formal sense.

[0047] Aiming at the problems of difficult network - forming new - energy fault - ride - through, poor stability of current - based fault - ride - through control, and poor support ability, etc., the present invention proposes a power - based network - forming new - energy fault - ride - through strategy for achieving amplitude - phase stability of network - forming new - energy, aiming to achieve network - forming new - energy fault - ride - through while achieving amplitude - phase stability of network - forming new - energy, and being able to maintain the fault - support ability of network - forming new - energy to the power grid.

[0048] Figure 1 Flowchart of a network - forming new - energy fault - ride - through method 100 for achieving amplitude - phase stability according to an embodiment of the present invention. As Figure 1 shown, the network - forming new - energy fault - ride - through method for achieving amplitude - phase stability provided by the embodiment of the present invention can achieve network - forming new - energy fault - ride - through only by adjusting the power reference value of the control link, only needs to add a control link at the front end of the network - forming control, reduces the modification of the original network - forming control link, has a small implementation difficulty, and this fault - ride - through strategy does not need to add a current loop in the network - forming control link. Compared with the traditional current - based fault - ride - through control, it improves the control response speed and stability of network - forming new - energy. The network - forming new - energy fault - ride - through method 100 for achieving amplitude - phase stability provided by the embodiment of the present invention starts from step 101. In step 101, when a power - grid fault occurs, the power - grid voltage amplitude and the deviation phase angle relative to the steady - state power - grid voltage are obtained based on the post - fault power - grid voltage.

[0049] Preferably, the obtaining of the power - grid voltage amplitude and the deviation phase angle relative to the steady - state power - grid voltage based on the post - fault power - grid voltage includes:

[0050] Based on the post-fault grid voltage, the grid voltage amplitude is obtained through amplitude extraction, and the phase angle deviation relative to the steady-state grid voltage is obtained through a phase-locked loop (PLL).

[0051] In step 102, power setting is performed based on the power angle of the system under steady state, the grid voltage amplitude, and the phase angle deviation to obtain the reference values of active power and reactive power.

[0052] Preferably, the power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the phase angle deviation to obtain the reference values of active power and reactive power includes:

[0053]

[0054] Where P c is the reference value of active power, k is the grid strength, |U g | is the post-fault grid voltage amplitude, δ is the power angle of the system under steady state, α is the phase angle deviation, Q c is the reference value of reactive power, and ρ is the resistance-inductance ratio.

[0055] In step 103, grid-forming control is performed based on the reference values of active power and reactive power to achieve fault ride-through.

[0056] Preferably, the method further includes:

[0057] When the grid is not faulty, the reference values of active power and reactive power are determined based on the maximum power point tracking (MPPT) of new energy steady-state control, and grid-forming control is performed.

[0058] The external characteristics of the grid-forming converter are equivalent to a constant voltage source, and the equivalent circuit of the converter grid-connected system is as Figure 2 shown. As shown in Figure 3 , during steady-state operation, with the grid voltage Ug as the orientation, the internal potential of the grid-forming new energy is equal to the voltage at the point of common coupling (PCC), and the power angle with the grid voltage is δ.

[0059] It can be derived that the active and reactive power expressions are shown in equations (1) and (2) respectively.

[0060]

[0061] For the endpoints, coordinate decomposition is performed. Taking the starting point as the origin, assuming the ending point coordinates are (x u , y u ), the active power expression is transformed into equation (3):

[0062]

[0063] Equation (3) is the algebraic equation of a circle. Therefore, the endpoint locus line (abbreviated as the U s -P locus line) is centered at with as the radius.

[0064] Similarly, by transforming the reactive power expression (2), Equation (4) is obtained:

[0065]

[0066] Similar to the U s -P locus, the endpoint locus line (abbreviated as the U s -Q locus line) that satisfies the reactive power transmission condition of the grid-connected system is centered at with as the radius.

[0067] Under steady state, the intersection point of the P-E locus line and the Q-E locus line is the endpoint of the phasor at this active and reactive power output level. The line connecting the origin and this point is the phasor. It can be seen from that there are two intersection points (point b and point c) on the two loci. The line connecting point a and the intersection point reflects the magnitude of the converter output current at this operating point. By comparison, the output current of the grid-forming converter at point c is too large and does not meet the actual operating conditions, so it is discarded. Therefore, point b is the endpoint of the grid-forming converter port voltage Figure 4 .

[0068] It is found by comparison that the P-E and Q-E loci are related to the grid impedance (resistance-inductance ratio, amplitude). Let the resistance-inductance ratio ρ = R s / X s . The P-E and Q-E loci are re-expressed using the resistance-inductance ratio ρ and the grid inductive reactance X s as shown in Equations (5) and (6) respectively.

[0069]

[0070] The voltage level at the PCC point is relatively high. In high-voltage level lines, the transmission line impedance ratio is relatively low, generally around 0.2. For the P-E locus circle, ρ is in the denominator of the q-axis coordinate of the center, so the center is on the negative half-axis of the q-axis and far from the d-axis. Similarly, due to the influence of ρ, the radius of this locus finally presents as an arc with a relatively low radian in the first quadrant.

[0071] ​For the Q-E locus circle, ρ is in the numerator of the q-axis coordinate of the center, so the center is on the positive q-axis. Relatively speaking, it is closer to the d-axis, and the radius is much smaller than that of the P-E locus circle, and it almost presents a complete circular locus in the first quadrant.

[0072] As Figure 5 shown, when ρ changes from 0.1 to 0.25, as ρ increases, the "bulge" of the U s -P locus becomes larger and larger, but the relative change is not significant, and it can be approximately considered that the U s -P locus is a straight line in the first quadrant, and the simplified P-E locus is as shown in Equation (7). The center of the Q-E locus circle rises as ρ increases, and the radius also changes significantly.

[0073]

[0074] The grid strength is usually represented by the short-circuit ratio k, as shown in Equation (8).

[0075]

[0076] The influence of the resistance-inductance ratio on the P-E locus can be ignored, and it can be approximately considered that the locus is a straight line. The P-E locus is represented by the short-circuit ratio k as shown in Equation (9). It can be seen from Equation (9) that the smaller the grid strength, the farther the P-E locus is from the d-axis.

[0077]

[0078] The influence of the resistance-inductance ratio in the grid impedance on the Q-E locus cannot be ignored. The resistive and inductive components of the grid impedance are represented by the resistance-inductance ratio ρ and the grid strength k, as shown in Equation (10).

[0079]

[0080] Substitute Equation (10) into Equation (4), and the Q-E locus is represented by the resistance-inductance ratio ρ and the grid strength k, as shown in Equation (11).

[0081]

[0082] It can be obtained from Equation (11) that the center of the Q-E locus circle represented by the resistance-inductance ratio ρ and the grid strength k is (U g / 2, ρU g / 2), and the radius is The center of the Q-E locus circle is not affected by the SCR, but when the reactive power output is not 0, the SCR affects the radius of the Q-E locus. As the SCR increases, the radius of the Q-E locus circle decreases.

[0083] Under steady-state conditions, the vector diagram of the grid-connected system is as Figure 6 shown. Taking the grid voltage Ug Taking the reference voltage (x-axis) as the basis, a rectangular coordinate system is established. The internal electromotive force of the network-forming new energy is E, and the voltage at the PCC point is U s , and the two coincide. The center of the reactive power trajectory circle is point O. As the voltage changes, the changing trajectory of the center of the reactive power trajectory circle is on the ray AO. The radius of the reactive power trajectory circle can be calculated by Equation (11). The active power trajectory is a straight line parallel to the x-axis, and its height can be calculated by Equation (9).

[0084] The intersection point of the active power trajectory line and the reactive power trajectory circle is point C. The vector between the intersection point C and the origin A is the port voltage of the network-forming converter. The vector AB is the voltage at the PCC point, and the vector BC is the product of the transmission line impedance and the grid-connected current.

[0085] After the grid fault, the voltage at the PCC point drops slightly. The inertia characteristic of the active power synchronization link causes the power angle to increase, generating unbalanced power, which leads to an increase in the system current. During the fault duration, under the action of the power synchronization link, by reducing the active power and increasing the reactive power, the power angle is restored to the steady-state level.

[0086] Under steady-state conditions, when the network-forming new energy is connected to the grid, a power reference value needs to be set. Generally, the power reference value is determined by the maximum power point tracking (MPPT) ability on the new energy side. The grid-connected power of the new energy directly determines the power angle between the internal electromotive force of the network-forming new energy and the grid voltage, as well as the amplitude of the voltage at the grid connection point.

[0087] In the case of a fault, if the power reference value given by MPPT is still used and the network-forming new energy maintains a constant grid-connected power, it will cause changes in the power angle and the amplitude at the grid connection point, resulting in the voltage being unable to maintain the steady-state level, causing the current to increase, and further leading to the locking of the new energy protection.

[0088] Therefore, the method of the present invention does not use the power reference value given by MPPT during the fault. Instead, it re-samples through a phase-locked loop (PLL) to obtain the phase angle α and amplitude |Ug| under the grid fault condition. The phase angle α, amplitude |Ug| under the grid fault condition, and the power angle δ under the steady-state condition are input into the power reconstruction calculation link to re-calculate the power reference value and input it into the control link of the network-forming new energy. The block diagram and flowchart of the control link are shown in Figure 7 and Figure 8 respectively. The vector diagram of the grid-connected system during the fault is shown in Figure 9 as shown.

[0089] Combined with Figure 7As shown, the control strategy of the present invention is to add a power setting link at the front end of the traditional network-forming control strategy. During the duration of the fault, by modifying the power reference value input to the network-forming control link, the power balance of the network-forming converter is controlled to achieve the fault ride-through of the network-forming converter.

[0090] As Figure 7 shown, the network-forming control link in the right half of the figure is the core, and the two left parts are used to give the power reference value. Among them, the upper left part is the power setting link designed by the present invention for fault conditions, and the lower left part is the power reference value setting link under steady-state conditions. The meanings of the physical quantities in the figure are as follows: U g is the grid voltage, |U g | is the grid voltage amplitude, α is the change angle of the post-fault grid voltage compared with the steady-state voltage, δ is the power angle of the system under steady-state conditions (the angle between the internal potential of the network-forming converter and the grid voltage), P c , Q c are the active and reactive power reference values under fault conditions given by the control strategy proposed in this patent respectively, P MPPT , Q MPPT are the active and reactive power reference values given by the new energy MPPT control under steady-state conditions respectively; P0 and Q0 are the active and reactive power reference values input to the network-forming control link respectively, P e , Q e are the active and reactive powers actually measured by the system injected from the network-forming converter into the grid respectively, and E is the amplitude of the internal potential of the network-forming converter.

[0091] Combined with Figure 8 shown, when the grid is operating normally without a fault, the power reference value of the network-forming new energy is given by the maximum efficiency tracking control strategy on the new energy side for the active and reactive power reference values P MPPT , Q MPPT .

[0092] When it is detected that a grid fault occurs, the post-fault grid voltage Ug obtains the current grid voltage amplitude |Ug| and the deviation phase angle α relative to the steady-state grid voltage through the phase-locked loop PLL, plus the angle (power angle) δ between the internal potential E of the network-forming new energy and the grid voltage Ug at steady state. The three are used as the inputs of the power setting calculation link. The power setting calculation link outputs the active and reactive power reference values Pc and Qc according to the input state quantities, and inputs Pc and Qc to the network-forming control part for adjustment to achieve fault ride-through.

[0093] Among them, the active power reference value and the reactive power reference value are obtained by using the following formulas, including:

[0094]

[0095] Among them, P c is the reference value of active power, k is the grid strength, |U g | is the amplitude of the grid voltage after the fault, δ is the power angle of the system under steady state, α is the deviation phase angle, Q c is the reference value of reactive power, and ρ is the resistance-inductance ratio.

[0096] Compared with the traditional current-based grid-forming new energy fault ride-through strategy, the grid-forming new energy fault ride-through method proposed by the present invention does not modify the ontology of the grid-forming control link, but only adds a power reference value reconstruction link at the front end, minimizing the modification to the grid-forming control link, maintaining the support ability of the grid-forming new energy, and improving the grid connection stability of the grid-forming new energy.

[0097] Figure 10 FIG. 13 is a schematic structural diagram of a grid-forming new energy fault ride-through system 1000 for realizing amplitude-phase stability according to an embodiment of the present invention. As Figure 10 shown, the grid-forming new energy fault ride-through system 1000 for realizing amplitude-phase stability provided by the embodiment of the present invention includes: a grid voltage amplitude and deviation phase angle acquisition unit 1001, an active and reactive power reference value acquisition unit 1002, and a control unit 1003.

[0098] Preferably, the grid voltage amplitude and deviation phase angle acquisition unit 1001 is configured to obtain the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the grid voltage after the grid fault occurs.

[0099] Preferably, the grid voltage amplitude and deviation phase angle acquisition unit 1001 obtains the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the grid voltage after the grid fault, including:

[0100] Based on the grid voltage after the grid fault, the grid voltage amplitude is obtained through amplitude extraction, and the deviation phase angle relative to the steady-state grid voltage is obtained through a phase-locked loop PLL.

[0101] Preferably, the active and reactive power reference value acquisition unit 1002 is configured to perform power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle, and obtain the reference value of active power and the reference value of reactive power.

[0102] Preferably, the active and reactive power reference value acquisition unit 1002 performs power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle, and obtains the reference value of active power and the reference value of reactive power, including:

[0103]

[0104] Among them, P cis the active power reference value, k is the grid strength, |U g | is the grid voltage amplitude after the fault, δ is the power angle of the system under steady state, α is the deviation phase angle, Q c is the reactive power reference value, and ρ is the resistance - inductance ratio.

[0105] Preferably, the control unit 1003 is configured to perform grid - forming control based on the active power reference value and the reactive power reference value to achieve fault ride - through.

[0106] Preferably, the control unit further includes:

[0107] When the power grid does not fail, determine the active power reference value and the reactive power reference value based on the new - energy steady - state control MPPT, and perform grid - forming control.

[0108] The grid - forming new - energy fault - ride - through system 1000 for realizing amplitude - phase stability in the embodiments of the present invention corresponds to the grid - forming new - energy fault - ride - through method 100 for realizing amplitude - phase stability in another embodiment of the present invention, and will not be elaborated here.

[0109] On the other hand of the present invention, the present invention provides a computer - readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the steps of any one of the methods for realizing grid - forming new - energy fault - ride - through with amplitude - phase stability.

[0110] On the other hand of the present invention, the present invention provides an electronic device, including:

[0111] The above - mentioned computer - readable storage medium; and

[0112] One or more processors for executing the program in the computer - readable storage medium.

[0113] The present invention has been described by referring to a few embodiments. However, as is well known to those skilled in the art, other embodiments equivalent to those disclosed above in the present invention equally fall within the scope of the present invention.

[0114] Generally, all terms used in the present invention are interpreted according to their ordinary meanings in the technical field, unless otherwise clearly defined therein. All references to "a / the [device, component, etc.]" are open - endedly interpreted as at least one instance of the device, component, etc., unless otherwise clearly stated. The steps of any method disclosed here do not necessarily need to be run in the exact order disclosed, unless clearly stated.

[0115] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0116] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or the combination of blocks.

[0117] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing devices to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or the combination of blocks.

[0118] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, so that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or the combination of blocks.

[0119] 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 them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: still can modify the specific implementation manners of the present invention or make equivalent substitutions, and any modification or equivalent substitution that does not deviate from the spirit and scope of the present invention should be covered by the protection scope of the present invention.

Claims

1. A grid-forming new energy fault ride-through method for achieving amplitude-phase stability, characterized in that The method includes: When a grid fault occurs, obtaining the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the post-fault grid voltage; Performing power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle to obtain the active power reference value and the reactive power reference value; Performing grid-forming control based on the active power reference value and the reactive power reference value to achieve fault ride-through.

2. The method according to claim 1, wherein The obtaining the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the post-fault grid voltage includes: Based on the post-fault grid voltage, obtaining the grid voltage amplitude through amplitude extraction and obtaining the deviation phase angle relative to the steady-state grid voltage through a phase-locked loop PLL.

3. The method according to claim 1, wherein The performing power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle to obtain the active power reference value and the reactive power reference value includes: Among them, P c is the reference value of active power, k is the grid strength, |U g | is the grid voltage amplitude after the fault, δ is the power angle of the system under steady state, α is the deviation phase angle, Q c is the reference value of reactive power, and ρ is the resistance - inductance ratio.

4. The method according to claim 1, characterized in that, The method further includes: When no grid fault occurs, determining the active power reference value and the reactive power reference value based on the maximum power point tracking (MPPT) of new energy steady-state control and performing grid-forming control.

5. A grid-forming new energy fault ride-through system for achieving amplitude-phase stability, characterized in that, The system includes: A voltage amplitude and deviation phase angle obtaining unit, configured to obtain the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the post-fault grid voltage when a grid fault occurs; An active and reactive power reference value obtaining unit, configured to perform power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle to obtain the active power reference value and the reactive power reference value; A control unit, configured to perform grid-forming control based on the active power reference value and the reactive power reference value to achieve fault ride-through.

6. The system according to claim 5, characterized in that The voltage amplitude and deviation phase angle obtaining unit obtaining the grid voltage amplitude and the deviation phase angle relative to the steady-state grid voltage based on the post-fault grid voltage includes: Based on the post-fault grid voltage, obtaining the grid voltage amplitude through amplitude extraction and obtaining the deviation phase angle relative to the steady-state grid voltage through a phase-locked loop PLL.

7. The system according to claim 5, characterized in that, The active and reactive power reference value obtaining unit performing power setting based on the power angle of the system under steady state, the grid voltage amplitude, and the deviation phase angle to obtain the active power reference value and the reactive power reference value includes: Among them, P c is the reference value of active power, k is the grid strength, |U g | is the grid voltage amplitude after the fault, δ is the power angle of the system under steady state, α is the deviation phase angle, Q c is the reference value of reactive power, and ρ is the resistance-inductance ratio.

8. The system according to claim 5, wherein The control unit further includes: When no grid fault occurs, determining the active power reference value and the reactive power reference value based on the maximum power point tracking (MPPT) of new energy steady-state control and performing grid-forming control.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 1-4.

10. An electronic device, characterized in that, It includes: The computer-readable storage medium described in claim 9; And One or more processors for executing the program in the computer-readable storage medium.

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