Photovoltaic grid-connected modeling method and device, computer equipment and storage medium

Abstract

The invention relates to a photovoltaic grid-connected modeling method and device, computer equipment and a storage medium. The method comprises the following steps: acquiring a photovoltaic grid-connected simulation model; the simulation component corresponds to a real component in the photovoltaic network; on the basis of a preset equivalent circuit of the simulation component, replacing the simulation component in the photovoltaic grid-connected simulation model so as to update the photovoltaic grid-connected simulation model; performing simulation verification on the updated photovoltaic grid-connected simulation model based on a preset illumination rule; and determining grid-connected description data of the updated photovoltaic grid-connected simulation model under the condition that the illumination suddenly changes, and determining that simulation verification of the grid-connected simulation model is passed under the condition that the grid-connected description data is the same as preset standard description data. By adopting the method, photovoltaic grid connection can be accurately modeled.

Description

Technical Field

[0001] This application relates to the field of modeling technology, and in particular to a photovoltaic grid-connected modeling method, apparatus, computer equipment, and storage medium. Background Technology

[0002] With the rapid development of distributed photovoltaic (PV) grid-connected technology, PV system modeling and simulation have become a research hotspot. Traditional modeling methods typically employ unit-level independent modeling, such as modeling key components like the PV array, combiner box, DC-DC converter, and inverter separately, and then building simplified models for analysis on a simulation platform. Traditional techniques often utilize idealized circuit models and control strategies, such as using the constant voltage tracking method for maximum power point tracking (MPPT) or the fixed-step perturbation observation method, to reduce model complexity and improve simulation efficiency.

[0003] However, current modeling methods or traditional approaches suffer from problems such as low model coupling and insufficient dynamic response accuracy. Specifically, existing combiner box control modeling lacks sufficient refinement, leading to issues like delayed equilibrium response and slow convergence speed of current fluctuations when the system encounters dynamic conditions such as sudden changes in light intensity. Furthermore, traditional modeling methods are limited to unit-level research and fail to achieve full system integration from the photovoltaic array to the grid connection point, resulting in insufficient accuracy of multi-level model coordination and difficulty in accurately simulating the actual operating characteristics of high-penetration photovoltaic grid-connected systems. Summary of the Invention

[0004] Therefore, it is necessary to provide a photovoltaic grid-connected modeling method, device, computer equipment, and storage medium that can accurately establish models to address the aforementioned technical problems.

[0005] Firstly, this application provides a photovoltaic grid-connected modeling method, including:

[0006] Obtain a photovoltaic grid-connected simulation model; the photovoltaic grid-connected simulation model includes at least one simulated component; the simulated component corresponds to the real component in the photovoltaic network;

[0007] Based on the preset equivalent circuit of the simulated components, the simulated components in the photovoltaic grid-connected simulation model are replaced to update the photovoltaic grid-connected simulation model.

[0008] Based on the preset illumination rules, the updated photovoltaic grid-connected simulation model is simulated and verified. The illumination rules are to maintain normal illumination for a preset duration and then perform abrupt changes on the normal illumination. The abrupt changes include increasing or decreasing the illumination.

[0009] The updated photovoltaic grid-connected simulation model is determined under the condition of sudden change in light intensity. The grid-connected description data of the updated photovoltaic grid-connected simulation model is determined. If the grid-connected description data is the same as the preset standard description data, the simulation verification of the grid-connected simulation model is determined to be successful.

[0010] In one embodiment, the simulation components include at least one of a simulated photovoltaic cell, a simulated combiner box, a simulated converter, and a simulated inverter; based on a preset equivalent circuit of the simulation components, the simulation components in the photovoltaic grid-connected simulation model are replaced to update the photovoltaic grid-connected simulation model, including:

[0011] Based on the equivalent circuit of a photovoltaic cell, the simulated photovoltaic cell is replaced to update the photovoltaic grid-connected simulation model; and,

[0012] Based on the forward converter circuit, the simulated combiner box is replaced to update the photovoltaic grid-connected simulation model; and,

[0013] Based on the equivalent circuit of the switching transistors, the simulated converter is replaced to update the photovoltaic grid-connected simulation model; and,

[0014] Based on the three-phase grid-connected inverter circuit, the simulated inverter is replaced to update the photovoltaic grid-connected simulation model.

[0015] In one embodiment, the simulated combiner box is replaced based on the forward converter circuit to update the photovoltaic grid-connected simulation model, including:

[0016] Based on the forward converter circuit, the simulated combiner box was replaced and connected with other simulated components to update the photovoltaic grid-connected simulation model; the forward converter circuit includes a primary winding, a secondary winding, a magnetic reset winding, and a proportional-integral (PI) controller;

[0017] Run the updated photovoltaic grid-connected simulation model to determine the total current value and the branch current value of at least one branch in the photovoltaic grid-connected simulation model;

[0018] Based on the total current value, the branch current values ​​of different branches, and the preset reference current value, the control signal of the PI controller is determined to update the photovoltaic grid-connected simulation model again.

[0019] In one embodiment, the control signal of the PI controller is determined based on the total current value, the branch current values ​​of different branches, and a preset reference current, including:

[0020] For each branch, the current difference between the branch current and the total current is determined, and the minimum current difference is selected as the balancing current.

[0021] The control signal for the PI controller is determined based on the relationship between the equalization current and the preset reference current.

[0022] In one embodiment, the simulated converter is replaced based on the equivalent circuit of the switching transistor, and the photovoltaic grid-connected simulation model is updated, including:

[0023] Based on the equivalent circuit of the switching transistor, the simulated converter is replaced and connected with other simulated components to update the photovoltaic grid-connected simulation model; the equivalent circuit of the switching transistor includes the switching transistor.

[0024] Run the updated photovoltaic grid-connected simulation model to determine the voltage change value of the photovoltaic grid-connected simulation model during the sampling period;

[0025] Based on the relationship between the voltage change value and the preset voltage threshold, the control strategy of the switching transistor is determined to update the photovoltaic grid-connected simulation model again.

[0026] The control strategy includes: maintaining the disturbance step size of the switching transistor control duty cycle when the voltage change value is equal to the preset voltage threshold; increasing the disturbance step size of the switching transistor control duty cycle when the voltage change value is greater than the preset voltage threshold; and decreasing the disturbance step size of the switching transistor control duty cycle when the voltage change value is less than the preset voltage threshold.

[0027] In one embodiment, the simulated inverter is replaced based on the three-phase grid-connected inverter circuit to update the photovoltaic grid-connected simulation model, including:

[0028] Based on the three-phase grid-connected inverter circuit, the simulated inverter was replaced and connected with other simulation components to update the photovoltaic grid-connected simulation model.

[0029] Run the updated photovoltaic grid-connected simulation model to determine the three-phase voltage values ​​of the three-phase grid-connected inverter circuit;

[0030] The three-phase voltage values ​​are decoupled to obtain the target voltage value;

[0031] Based on the target voltage value and the preset triangular carrier wave, the control strategy of the three-phase grid-connected inverter circuit is determined to update the photovoltaic grid-connected simulation model again.

[0032] Secondly, this application also provides a photovoltaic grid-connected modeling device, comprising:

[0033] The acquisition module is used to acquire the photovoltaic grid-connected simulation model; the photovoltaic grid-connected simulation model includes at least one simulated component; the simulated component corresponds to the real component in the photovoltaic network;

[0034] The replacement module is used to replace the simulation components in the photovoltaic grid-connected simulation model based on the preset equivalent circuit of the simulation components, so as to update the photovoltaic grid-connected simulation model.

[0035] The verification module is used to perform simulation verification on the updated photovoltaic grid-connected simulation model based on preset illumination rules. The illumination rules are to maintain normal illumination for a preset duration and then perform abrupt changes on the normal illumination. The abrupt changes include increasing or decreasing the illumination.

[0036] The determination module is used to determine the grid connection description data of the updated photovoltaic grid connection simulation model under the condition of sudden change in light intensity, and to determine that the simulation verification of the grid connection simulation model has passed if the grid connection description data is the same as the preset standard description data.

[0037] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0038] Obtain a photovoltaic grid-connected simulation model; the photovoltaic grid-connected simulation model includes at least one simulated component; the simulated component corresponds to the real component in the photovoltaic network;

[0039] Based on the preset equivalent circuit of the simulated components, the simulated components in the photovoltaic grid-connected simulation model are replaced to update the photovoltaic grid-connected simulation model.

[0040] Based on the preset illumination rules, the updated photovoltaic grid-connected simulation model is simulated and verified. The illumination rules are to maintain normal illumination for a preset duration and then perform abrupt changes on the normal illumination. The abrupt changes include increasing or decreasing the illumination.

[0041] The updated photovoltaic grid-connected simulation model is determined under the condition of sudden change in light intensity. The grid-connected description data of the updated photovoltaic grid-connected simulation model is determined. If the grid-connected description data is the same as the preset standard description data, the simulation verification of the grid-connected simulation model is determined to be successful.

[0042] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the following steps:

[0043] Obtain a photovoltaic grid-connected simulation model; the photovoltaic grid-connected simulation model includes at least one simulated component; the simulated component corresponds to the real component in the photovoltaic network;

[0044] Based on the preset equivalent circuit of the simulated components, the simulated components in the photovoltaic grid-connected simulation model are replaced to update the photovoltaic grid-connected simulation model.

[0045] Based on the preset illumination rules, the updated photovoltaic grid-connected simulation model is simulated and verified. The illumination rules are to maintain normal illumination for a preset duration and then perform abrupt changes on the normal illumination. The abrupt changes include increasing or decreasing the illumination.

[0046] The updated photovoltaic grid-connected simulation model is determined under the condition of sudden change in light intensity. The grid-connected description data of the updated photovoltaic grid-connected simulation model is determined. If the grid-connected description data is the same as the preset standard description data, the simulation verification of the grid-connected simulation model is determined to be successful.

[0047] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, performs the following steps:

[0048] Obtain a photovoltaic grid-connected simulation model; the photovoltaic grid-connected simulation model includes at least one simulated component; the simulated component corresponds to the real component in the photovoltaic network;

[0049] Based on the preset equivalent circuit of the simulated components, the simulated components in the photovoltaic grid-connected simulation model are replaced to update the photovoltaic grid-connected simulation model.

[0050] Based on the preset illumination rules, the updated photovoltaic grid-connected simulation model is simulated and verified. The illumination rules are to maintain normal illumination for a preset duration and then perform abrupt changes on the normal illumination. The abrupt changes include increasing or decreasing the illumination.

[0051] The updated photovoltaic grid-connected simulation model is determined under the condition of sudden change in light intensity. The grid-connected description data of the updated photovoltaic grid-connected simulation model is determined. If the grid-connected description data is the same as the preset standard description data, the simulation verification of the grid-connected simulation model is determined to be successful.

[0052] The aforementioned photovoltaic grid-connected modeling method, apparatus, computer equipment, and storage medium, by employing a pre-defined equivalent circuit to finely replace components in the simulation model and introducing verification rules that include sudden changes in illumination, effectively improve the accuracy and reliability of the photovoltaic grid-connected simulation model under dynamic operating conditions. This method can accurately simulate the dynamic response of the system under drastic changes in illumination, ensuring that key parameters such as grid-connected current, voltage, and power meet pre-defined standards. This significantly enhances the ability to predict and verify the stable operating state of high-penetration photovoltaic grid-connected systems, providing a reliable basis for system optimization and fault prevention. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is an application environment diagram of a photovoltaic grid-connected modeling method provided in this embodiment;

[0055] Figure 2A This is a flowchart illustrating a photovoltaic grid-connected modeling method provided in this embodiment;

[0056] Figure 2B This embodiment provides a refined modeling framework diagram for a distributed photovoltaic grid-connected system.

[0057] Figure 2C This is a schematic diagram of an equivalent circuit of a photovoltaic cell provided in this embodiment;

[0058] Figure 3A This is a flowchart illustrating the first step of updating the photovoltaic grid-connected simulation model provided in this embodiment;

[0059] Figure 3B This is a schematic diagram of a forward converter circuit provided in this embodiment;

[0060] Figure 3C This embodiment provides a block diagram of a control strategy for minimizing the equalization current.

[0061] Figure 3D This embodiment provides a control block diagram;

[0062] Figure 4A This is a flowchart illustrating the second step in updating the photovoltaic grid-connected simulation model provided in this embodiment;

[0063] Figure 4B This embodiment provides a schematic diagram of an equivalent circuit for a switching transistor.

[0064] Figure 5A This is a flowchart illustrating the third step in updating the photovoltaic grid-connected simulation model provided in this embodiment;

[0065] Figure 5B This embodiment provides a schematic diagram of a three-phase grid-connected inverter circuit;

[0066] Figure 5C This is a schematic diagram of a three-phase inverter topology provided in this embodiment;

[0067] Figure 5DThis embodiment provides a main working diagram of the current inner loop;

[0068] Figure 5E This embodiment provides an overall control block diagram for a voltage and current dual closed loop.

[0069] Figure 6 This is a structural block diagram of a photovoltaic grid-connected modeling device provided in this embodiment;

[0070] Figure 7 This is an internal structural diagram of a computer device provided in this embodiment. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0072] The photovoltaic grid-connected modeling method provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be integrated on server 104 or placed on a cloud or other network server. A computer device acquires a photovoltaic grid-connected simulation model; the photovoltaic grid-connected simulation model includes at least one simulation component; the simulation component corresponds to a real component in the photovoltaic network; based on the preset equivalent circuit of the simulation component, the simulation component in the photovoltaic grid-connected simulation model is replaced to update the photovoltaic grid-connected simulation model; based on preset illumination rules, the updated photovoltaic grid-connected simulation model is simulated and verified; the illumination rules are to maintain normal illumination for a preset duration and then perform a sudden change in normal illumination; the sudden change includes increasing or decreasing illumination; the grid-connected description data of the updated photovoltaic grid-connected simulation model under the condition of sudden illumination changes is determined, and if the grid-connected description data is the same as the preset standard description data, the simulation verification of the grid-connected simulation model is determined to be successful. The terminal 102 can be, but is not limited to, various personal computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. IoT devices can include smart speakers, smart TVs, smart air conditioners, and smart in-vehicle systems. Portable wearable devices can include smartwatches, smart bracelets, and head-mounted devices. The server 104 can be implemented using a standalone server or a server cluster consisting of multiple servers.

[0073] In one exemplary embodiment, such as Figure 2A As shown, a photovoltaic grid-connected modeling method is provided, which can be applied to... Figure 1Taking a computer device as an example, the explanation includes the following steps S201 to S204. Wherein:

[0074] S201 obtains the photovoltaic grid-connected simulation model.

[0075] Among them, the photovoltaic grid-connected simulation model is a model constructed using computer simulation technology to simulate and analyze the grid-connection process of a distributed photovoltaic system. This model includes simulated components corresponding to real components in the photovoltaic network (such as simulated photovoltaic cells, simulated combiner boxes, simulated converters, and simulated inverters), and replaces and updates these simulated components through preset equivalent circuits to achieve accurate simulation and verification of the grid-connected performance of the photovoltaic system under various operating conditions (including dynamic conditions such as sudden changes in sunlight).

[0076] The photovoltaic grid-connected simulation model includes at least one simulated component; this simulated component corresponds to a real component in the photovoltaic network; the simulated component includes at least one of simulated photovoltaic cells, simulated combiner boxes, simulated converters, and simulated inverters. The simulated photovoltaic cell can be understood as a virtual model built based on the equivalent circuit of a photovoltaic cell, used to simulate the electrical performance output characteristics of an actual photovoltaic cell under changes in light and temperature. The simulated combiner box can be understood as a virtual device designed using a forward converter circuit model, dynamically adjusting the current of each branch through a PI controller to simulate the current balancing and control function of the actual combiner box on the photovoltaic array output. The simulated converter can be understood as a virtual power conversion device built based on the equivalent circuit of a switching transistor, achieving voltage conversion by adjusting the duty cycle, simulating the power quality regulation function of an actual DC-DC converter in a photovoltaic system. The simulated inverter can be understood as a virtual device designed using a three-phase grid-connected inverter circuit model, achieving DC-to-AC conversion through a dual closed-loop control strategy, simulating the synchronous operation and power control function of an actual inverter with the grid.

[0077] For example, such as Figure 2B The diagram shows a detailed modeling framework for a distributed photovoltaic grid-connected system. Comprehensive and detailed modeling of this system accurately reflects its dynamics and provides a reliable foundation for subsequent analysis and optimization.

[0078] S202 replaces the simulation components in the photovoltaic grid-connected simulation model based on the preset equivalent circuit of the simulation components, so as to update the photovoltaic grid-connected simulation model.

[0079] In this context, simulated components can be understood as virtual components in a photovoltaic grid-connected simulation model that correspond to real photovoltaic network components (such as photovoltaic cells, combiner boxes, converters, inverters, etc.), used to simulate the electrical characteristics and operating behavior of actual equipment. Preset equivalent circuits can be understood as theoretical circuit models designed for simulated components (such as photovoltaic cell equivalent circuits, forward converter circuits, switching transistor equivalent circuits, etc.), using mathematical equations to describe the input-output relationships of components under specific operating conditions, thus replacing the actual circuits for digital simulation.

[0080] In some embodiments, based on the preset equivalent circuit of the simulated components, the simulated components in the photovoltaic grid-connected simulation model are replaced with the corresponding equivalent circuit to update the photovoltaic grid-connected simulation model.

[0081] For example, based on the equivalent circuit of a photovoltaic cell, the simulated photovoltaic cell is replaced to update the photovoltaic grid-connected simulation model: such as... Figure 2C The equivalent circuit diagram of the photovoltaic cell shown is used to calculate the current flowing out of the diode and the current flowing through the parallel resistor according to Kirchhoff's current law. The characteristic equation of the photovoltaic cell IU is shown in the following formula (1):

[0082] (1)

[0083] Among them, I ph I0 is the photocurrent; I0 is the diode reverse saturation current; q is the electron charge, q = 1.6 × 102 -19C ;R s and R sh These represent the series resistance and parallel resistance of the equivalent circuit, respectively; K is Boltzmann's constant, K = 1.38 × 10⁻⁶. -23 J / K; A is the ideality factor of the PN junction, typically taken as 1; T is the absolute temperature. This method allows for the creation of a more realistic photovoltaic cell model.

[0084] For example, based on the forward converter circuit, the simulated combiner box is replaced to update the photovoltaic grid-connected simulation model: based on the forward converter circuit, the simulated combiner box is replaced and connected with other simulation components to update the photovoltaic grid-connected simulation model.

[0085] For example, the simulated converter is replaced based on the equivalent circuit of the switching transistor to update the photovoltaic grid-connected simulation model: the simulated converter is replaced based on the equivalent circuit of the switching transistor and connected with other simulation components to update the photovoltaic grid-connected simulation model.

[0086] For example, based on a three-phase grid-connected inverter circuit, the simulated inverter is replaced to update the photovoltaic grid-connected simulation model: based on a three-phase grid-connected inverter circuit, the simulated inverter is replaced and connected with other simulation components to update the photovoltaic grid-connected simulation model.

[0087] S203 uses preset illumination rules to perform simulation verification on the updated photovoltaic grid-connected simulation model.

[0088] The lighting rule is to maintain normal lighting for a preset duration and then perform a sudden change on the normal lighting; the sudden change includes increasing or decreasing the lighting.

[0089] In some embodiments, after the updated photovoltaic grid-connected simulation model has been simulated and verified based on normal illumination for a preset time, a sudden change is applied to the normal illumination to simulate and verify the updated photovoltaic grid-connected simulation model again.

[0090] S204 determines the updated photovoltaic grid-connected simulation model under the condition of sudden change in light intensity, the updated photovoltaic grid-connected simulation model's grid-connected description data, and if the grid-connected description data is the same as the preset standard description data, determines that the simulation verification of the grid-connected simulation model has passed.

[0091] In some embodiments, simulation verification shows that after fluctuations in the equalization current output of the combiner box during sudden changes in illumination, it gradually stabilizes. The currents Ie1, Ie2, and Ie3 of each branch stabilize at 3.7A, 1.8A, and close to 0A, respectively, reflecting the effectiveness of the equalization control and demonstrating the improved refinement of the combiner control model. Simulation results such as the DC bus voltage stabilizing rapidly to approximately 800V, the grid-connected power remaining at around 1.9MW, and the rapid convergence of the dq-axis currents (Id approximately -20A, Iq close to 0) verify that the refined model can accurately capture the key dynamic characteristics of the system and confirm the effectiveness of the coordinated operation of each component.

[0092] The aforementioned photovoltaic grid-connected modeling method, by employing a pre-defined equivalent circuit to finely replace components in the simulation model and introducing verification rules that incorporate sudden changes in illumination, effectively improves the accuracy and reliability of the photovoltaic grid-connected simulation model under dynamic operating conditions. This method can accurately simulate the dynamic response of the system under drastic changes in illumination, ensuring that key parameters such as grid-connected current, voltage, and power meet pre-defined standards. This significantly enhances the ability to predict and verify the stable operating state of high-penetration photovoltaic grid-connected systems, providing a reliable basis for system optimization and fault prevention.

[0093] Figure 3A This is a flowchart illustrating the process of updating a photovoltaic grid-connected simulation model in one embodiment. This embodiment refines the steps in the above embodiment where the simulated combiner box is replaced based on the forward converter circuit to update the photovoltaic grid-connected simulation model, including the following steps:

[0094] The S301, based on a forward converter circuit, replaces the simulated combiner box and connects with other simulated components to update the photovoltaic grid-connected simulation model.

[0095] The forward converter circuit includes a primary winding, a secondary winding, a magnetic reset winding, and a proportional-integral (PI) controller. For example,... Figure 3B The diagram shows a forward converter circuit. The outputs of the three windings on the secondary side are connected to the respective photovoltaic arrays. R is used in the diagram. i This indicates that the control system detects the compensation current I on the secondary side. ei The system generates corresponding PWM control signals to adjust the on and off times of the main switch V. When a compensation current is detected, the control system adjusts the PWM signal, changing the duty cycle of the main switch V, thereby affecting the energy transferred from the transformer to the secondary side and correcting the magnitude and distribution of the compensation current. Where N... P For the primary winding, N R It is a magnetic reset winding.

[0096] In some embodiments, the forward converter circuit is replaced in the location of the simulated combiner box and connected to other simulated components to update the photovoltaic grid-connected simulation model.

[0097] S302 runs the updated photovoltaic grid-connected simulation model to determine the total current value and the branch current value of at least one branch of the photovoltaic grid-connected simulation model.

[0098] In some embodiments, when the switch is turned on T on =DT S During this period, the power supply voltage U in Add to N P The current flowing through the primary winding increases linearly, and the magnetic flux of the iron core increases linearly. The induced electromotive force and the induced electromotive force of the secondary winding are shown in the following equation (2).

[0099] (2)

[0100] Under normal circumstances, the primary current of the forward converter is fed back to each PV to provide equalization current; PV is... Figure 3B In the load section of the circuit, each array consists of identical photovoltaic cells connected in series and parallel in the same arrangement. Secondary side VD i1 When the circuit is turned on, the increase in magnetic flux is as shown in equation (3):

[0101] (3)

[0102] At the T when the switch is off off =(1-D)T SDuring this period, the primary winding current is reduced to zero, the magnetic flux decreases, and the induced electromotive force of each winding reverses, i.e., N Si The induced electromotive force is less than zero, making VD i1 As of now, I L After VD i2 Freewheeling, magnetic reset winding N R The induced electromotive force is less than zero, and the magnetic energy corresponding to the excitation current of the power supply is returned to the power supply voltage U. in If the magnetic reset current does not decay to zero during the switch-off period, the voltage across the magnetic reset winding will remain constant at U. in If the increase in magnetic flux is greater than the decrease in magnetic flux within a cycle, the iron core will quickly become saturated and unable to continue working. Therefore, the maximum duty cycle is obtained by setting the two equal, as shown in equation (4) below:

[0103] (4)

[0104] When modeling the forward converter, the turns ratio of each winding is first determined, and then the approximate range of the duty cycle is determined. The maximum critical load current is shown in (5) below:

[0105] (5)

[0106] By ensuring that the inductor current is continuous, the value of the inductor can be obtained as shown in the following formula (6):

[0107] (6)

[0108] Similarly, to ensure that the ripple factor of the secondary output voltage is 1%, the value of the capacitor is as shown in equation (7):

[0109] (7)

[0110] To balance accuracy and efficiency, a multi-scale modeling method is used to handle the switching elements in the forward converter. Using an equivalent small-signal model, controlled voltage sources and controlled current sources are used to replace the primary-side switches and secondary-side diodes, respectively, thus preserving the key dynamic characteristics of the system while significantly reducing computational complexity. The duty cycle-output voltage transfer function of the forward converter is shown in equation (8).

[0111] (8)

[0112] Where V(S) is the output voltage, d(s) is the control signal of the controlled source, which is related to the duty cycle D, and n is the winding turns ratio N. si / N P U in R is the input voltage of the forward converter and also the input voltage of the boost converter. iThis is the equivalent resistance of the photovoltaic array.

[0113] S303 determines the control signal of the PI controller based on the total current value, the branch current values ​​of different branches, and the preset reference current value, so as to update the photovoltaic grid-connected simulation model again.

[0114] In some embodiments, for each branch, the current difference of the branch current is determined based on the difference between the total current value and the branch current value, and the smallest current difference is selected as the equalization current; the control signal of the PI controller is determined based on the relationship between the equalization current and the preset reference current.

[0115] For example, such as Figure 3C The control strategy block diagram shown is based on the minimum equalization current. It compares the total current I... S and module current I PVm The value is used to determine whether each photovoltaic module needs additional current to reach or maintain its maximum power point.

[0116] For example, in a photovoltaic system, the total current I S This represents the sum of currents generated by all photovoltaic modules connected in series and parallel, while the module current I... PVm This represents the current output of a single photovoltaic module under current conditions. When I S More than I PVm When I < 1, it indicates that some modules may require additional current support to reach their maximum power point. In this case, the current equalizer will compensate for the modules with lower current. Conversely, when I < 1, it indicates that some modules may require additional current support to reach their maximum power point. S Less than or equal to I PVm At this point, the system may have reached a state of equilibrium or may not require additional equilibration operations, as summarized in equation (9).

[0117] (9)

[0118] The output current of the combiner box is I. O The input current of the forward converter is I. e-in The real-time output current of each photovoltaic array is I. PVm The compensation current output by the equalizer is I. ei Then the following relationship holds: I S =I O +I e-in =I PVm +I ei When connected in series, the output current of each PV module is equal, therefore comparing I... S and I PVm This allows us to determine whether the PV module is operating at its maximum power point. Let I... S =I PVm(Unobstructed, i.e., the PV output current at its maximum power point during normal operation), balancing the current input to other PVs. Requirement I S I equals the unshielded PV PVm Current compensation is only applied to the light-blocking PV to achieve I S .

[0119] The current equalizer only provides equalizing current to the shaded PV modules, not to the unshaded modules. This is achieved by selecting the minimum equalizing current I. e-min This ensures that the balancing current of unshielded modules (i.e., modules that do not require balancing) is zero. The control block diagram is as follows: Figure 3D As shown. Using the above-mentioned equal-balance control strategy, the PI controller controls the output of the equal current of each controlled voltage source through the PWM output pulse signal. The control equation is shown in the following equation.

[0120] (10)

[0121] The first part is the model of the forward converter, with the proportionality constant K. p T iS For the proportional and integral control coefficients of the PI controller; I ref i is the reference current; e-min D represents the minimum balancing current; D is the stable duty cycle, controlled by PWM output. In the simulation, the photovoltaic panel outputs a series current I. S The input to the boost converter also serves as the input to the primary side of the forward converter, feeding back to each secondary side as I. ei .

[0122] In the above embodiments, by introducing a forward converter circuit to replace the simulated combiner box and integrating a PI controller to achieve dynamic current balancing, the accuracy and response speed of the photovoltaic grid-connected simulation model under dynamic operating conditions are effectively improved. Specifically, it accurately simulates the current distribution and control logic of the actual combiner box, so that the total current and the current of each branch match the preset reference value in real time. At the same time, the system stability is optimized by dynamically adjusting the PI control signal, thereby significantly enhancing the model's adaptability to complex scenarios such as sudden changes in light intensity and providing a reliable verification tool for the stable operation of high-penetration photovoltaic grid connection.

[0123] Figure 4A This is a flowchart illustrating the process of updating the photovoltaic grid-connected simulation model in one embodiment. This embodiment refines the steps of updating the photovoltaic grid-connected simulation model by replacing the simulated converter based on the equivalent circuit of the switching transistors in the above embodiments, including the following steps:

[0124] The S401, based on the equivalent circuit of the switching transistor, replaces the simulated converter and connects with other simulation components to update the photovoltaic grid-connected simulation model.

[0125] The equivalent circuit of the switching transistor includes the switching transistor. For example... Figure 4B The equivalent circuit diagram of the switch shown is modeled using the small-signal switch equivalent substitution method to reveal the dynamic characteristics of the boost converter and effectively capture the behavior of the switching devices and the non-ideal characteristics of the components.

[0126] In some embodiments, the equivalent circuit of the switching transistor is replaced in the position of the simulated converter and connected with other simulation components to update the photovoltaic grid-connected simulation model.

[0127] S402 runs the updated photovoltaic grid-connected simulation model to determine the voltage change value of the photovoltaic grid-connected simulation model during the sampling period.

[0128] In some embodiments, the input impedance of the Boost converter is defined as shown in the following formula (11):

[0129] (11)

[0130] Among them, I in (s) is the converter input current, V in (s) represents the input port voltage of the converter. For a boost converter, its input impedance is shown in equation (12) below:

[0131] (12)

[0132] Where D represents the duty cycle, RL represents the load resistance, L represents the filter inductance, and C represents the parallel capacitor at the output terminal. Therefore, the entire boost circuit can be equivalently represented by this input impedance, which facilitates subsequent MPPT control modeling.

[0133] S403 determines the control strategy of the switching transistor based on the relationship between the voltage change value and the preset voltage threshold, so as to update the photovoltaic grid-connected simulation model again.

[0134] The control strategy includes: maintaining the disturbance step size of the switching transistor control duty cycle when the voltage change value is equal to the preset voltage threshold; increasing the disturbance step size of the switching transistor control duty cycle when the voltage change value is greater than the preset voltage threshold; and decreasing the disturbance step size of the switching transistor control duty cycle when the voltage change value is less than the preset voltage threshold.

[0135] In some embodiments, maximum power point tracking (MPP) control methods are diverse, the core of which lies in controlling the solar cell to operate at a specific voltage to achieve maximum power output based on illumination and temperature conditions. Traditional methods, such as constant voltage tracking, perturbation observation, incremental conductance, open-circuit voltage, and short-circuit current methods, mostly employ a fixed step size. To improve tracking accuracy, a variable step size strategy is introduced, adjusting the step size by detecting voltage increments (i.e., the sign change of the voltage difference between the current and previous sampling moments). A parameter C = x × X is set, where x is the voltage difference between the current and previous moments, and X is the value of x in the previous cycle. When C > 0, it indicates that the operating voltage is on the same side at the maximum power point (MPP), and the initial step size d is maintained for continued perturbation; when C < 0, it indicates that the MPP has been crossed, and the step size is reduced (adjusted by a step size factor A) until the step size is reduced to zero and stabilizes at the MPP; when C = 0, the MPP is reached, and the step size d is zero.

[0136] In the above embodiments, by replacing the simulated converter with an equivalent circuit of the switching transistor and integrating a dynamic control strategy, the simulation accuracy and response efficiency of the photovoltaic grid-connected simulation model for the nonlinear characteristics of the converter are significantly improved. Specifically, the real-time impact of the switching transistor's operation on voltage fluctuations is accurately captured, the control duty cycle is dynamically adjusted based on the comparison between the voltage change value and the preset threshold, effectively suppressing voltage over-limit problems, and the voltage regulation performance of the converter is optimized through a closed-loop feedback mechanism, thereby enhancing the model's adaptability under complex operating conditions and providing reliable simulation support for the efficient and stable operation of the photovoltaic system.

[0137] Figure 5A This is a flowchart illustrating the process of updating a photovoltaic grid-connected simulation model in one embodiment. This embodiment refines the steps in the above embodiment where the simulated combiner box is replaced based on the forward converter circuit to update the photovoltaic grid-connected simulation model, including the following steps:

[0138] The S501 is based on a three-phase grid-connected inverter circuit. It replaces the simulated inverter and connects it with other simulation components to update the photovoltaic grid-connected simulation model.

[0139] For example, such as Figure 5B The schematic diagram of the three-phase grid-connected inverter circuit shown is shown. The three-phase grid-connected inverter circuit adopts a dual closed-loop decoupling control strategy based on the transfer function. The outer loop PI controller stabilizes the DC bus voltage, and the inner loop adjusts the active and reactive currents respectively through dq axis decoupling control to achieve synchronous and stable operation with the grid.

[0140] In some embodiments, a three-phase grid-connected inverter circuit is used to replace the position of the simulated inverter and is connected to other simulation components to update the photovoltaic grid-connected simulation model.

[0141] The S502 runs the updated photovoltaic grid-connected simulation model to determine the three-phase voltage values ​​of the three-phase grid-connected inverter circuit.

[0142] In some embodiments, the three-phase grid-connected inverter circuit is subjected to coordinate transformation, transforming the three-phase coordinate system into a synchronous rotating dq coordinate system. Assuming that the initial phase of the A-phase voltage is zero, the voltage represented in the three-phase stationary coordinate system is as shown in the following formula (13):

[0143] (13)

[0144] The expression for the dq-axis voltage obtained after coordinate transformation is shown in the following formula (14):

[0145] (14)

[0146] A phase-locked loop (PLL) forms a type-II system through PI regulation and an integral element, achieving q-axis directional phase-locking and ensuring that the output phase matches the input phase. Three-phase grid-connected inverters use Clark and Park transformations to achieve dq-coordinate system phase-locking, while 220V single-phase systems require constructing virtual orthogonal signals. Alpha-Beta signals are obtained by providing a phase difference or using a second-order integral method to adapt to suboptimal grid conditions.

[0147] S503 decouples the three-phase voltage values ​​to obtain the target voltage value.

[0148] For example, such as Figure 5C The diagram shows a three-phase inverter topology. S1-6 represent the switches of the inverter bridge arms, L1 and L2 are the filter inductors on the inverter side and grid side, respectively, R1 and R2 are the internal resistances of the inductors, C is the filter capacitor of the LCL circuit, ug is the grid voltage, uc is the filter capacitor voltage, i1 and i2 are the inverter output current and grid-connected input current, respectively, ic is the filter capacitor current, and uabc is the inverter output voltage. To perform detailed modeling of the inverter circuit, it is necessary to analyze the inverter model in different coordinate systems throughout the control process. The inverter-side voltage is related to the DC-side voltage and the switching function. The inverter-side output current i is selected... 1k Filter capacitor voltage u ck and grid-connected current i 2k Taking the state variables as the basis, the Laplace transform yields the following inverter model expression, as shown in formula (15):

[0149] (15)

[0150] After the Park transformation, the model in the static abc coordinate system is transformed into the synchronously rotating dq coordinate system. The inverter model also changes accordingly. The specific transformation process has been described in the section on phase-locked loops, and will not be elaborated on here. The state equation in the dq coordinate system is shown in equation (16) below:

[0151] (16)

[0152] As can be seen from the above, the d-axis and q-axis have a strong coupling relationship, which will affect the control strategy.

[0153] A dual-loop decoupling control strategy is adopted. The inverter models in the three-phase stationary coordinate system and the dq synchronous rotating coordinate system are known. The current control equation is constructed by adding the corresponding coupling disturbance terms, as shown in equation (17):

[0154] (17)

[0155] Among them, K ip and K iI These are the proportional and integral adjustment coefficients for the inner current loop. and This is a reference value. The differential term of the inverter output current is obtained by calculation using a PI controller, and other coupling terms are obtained through feedforward compensation.

[0156] Based on the target voltage value and the preset triangular carrier wave, S504 determines the control strategy of the three-phase grid-connected inverter circuit to update the photovoltaic grid-connected simulation model again.

[0157] For example, such as Figure 5D The diagram shown is the main workflow of the inner current loop. In the inner current loop block diagram, the input is the reference value I, which corresponds to the active current and reactive current. d * I q * The sampled values ​​I of the active and reactive current output by the inverter. d I q Through continuous adjustments by both parties, the effect of current closed-loop control was finally achieved.

[0158] The inverter is equivalent to an inertial element G2(s), T S Given the sampling period of the current loop, the PI regulator of the inner current loop is G1(s), and the transfer function of the inverter output-side filter inductor is G3(s). The open-loop transfer function of the current loop can be obtained as shown in equation (18):

[0159] (18)

[0160] Among them, K piK is the proportionality constant of the current loop. ii K is the integral constant of the current loop. PWM For inverter gain, T s The sampling period of the current loop is given. By using the zero-point cancellation principle of the PI controller to cancel out the maximum time constant, the proportional constant K can be obtained. p and integration constant K i The closed-loop transfer function of the current loop is shown in equation (19):

[0161] (19)

[0162] When designing the voltage outer loop, the influence of the current inner loop needs to be considered. When the DC side voltage increases, the output current of the inverter can be increased through voltage closed-loop control, thereby reducing the DC voltage, which is the principle of energy conservation. The transfer function of the PI regulator of the voltage outer loop is shown in equation (20) below:

[0163] (20)

[0164] Combining the closed-loop transfer function of the inner current loop above, the open-loop transfer function of the outer voltage loop can be obtained as shown in equation (21):

[0165] (twenty one)

[0166] Therefore, the closed-loop transfer function can be obtained as shown in equation (22):

[0167] (twenty two)

[0168] Based on the above analysis, we can obtain the following: Figure 5E The diagram shows the overall control block diagram with dual closed-loop voltage and current control.

[0169] In the above embodiments, by replacing the simulated inverter with a three-phase grid-connected inverter circuit and introducing a decoupling control strategy, the dynamic response accuracy and stability of the photovoltaic grid-connected simulation model to the three-phase AC system are significantly improved. Specifically, this is manifested in: accurately extracting the dq-axis components of the three-phase voltage to achieve decoupling control and eliminate coupling interference; dynamically generating PWM control signals based on the comparison of the target voltage and the triangular carrier wave to optimize the output waveform quality and power factor of the inverter; and ensuring that the grid-connected current is synchronized with the grid voltage through a closed-loop feedback mechanism, thereby effectively suppressing harmonic pollution, enhancing the model's adaptability in complex grid environments, and providing reliable simulation verification for the stable operation of high-penetration photovoltaic grid-connected systems.

[0170] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0171] Based on the same inventive concept, this application also provides a photovoltaic grid-connected modeling device for implementing the photovoltaic grid-connected modeling method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more photovoltaic grid-connected modeling device embodiments provided below can be found in the limitations of the photovoltaic grid-connected modeling method described above, and will not be repeated here.

[0172] In one exemplary embodiment, such as Figure 6 As shown, a photovoltaic grid-connected modeling device is provided, including: an acquisition module 10, a replacement module 11, a verification module 12, and a determination module 13, wherein:

[0173] Module 10 is used to acquire a photovoltaic grid-connected simulation model; the photovoltaic grid-connected simulation model includes at least one simulation component; the simulation component corresponds to the real component in the photovoltaic network;

[0174] Replacement module 11 is used to replace the simulation components in the photovoltaic grid-connected simulation model based on the preset equivalent circuit of the simulation components, so as to update the photovoltaic grid-connected simulation model.

[0175] Verification module 12 is used to perform simulation verification on the updated photovoltaic grid-connected simulation model based on preset illumination rules. The illumination rules are to maintain normal illumination for a preset duration and then perform abrupt changes on the normal illumination. The abrupt changes include increasing or decreasing illumination.

[0176] The determination module 13 is used to determine the grid connection description data of the updated photovoltaic grid connection simulation model under the condition of sudden change in light intensity, and to determine that the simulation verification of the grid connection simulation model is passed if the grid connection description data is the same as the preset standard description data.

[0177] In some embodiments, the replacement module 11 is further configured to replace the simulated photovoltaic cell based on the photovoltaic cell equivalent circuit to update the photovoltaic grid-connected simulation model; and replace the simulated combiner box based on the forward converter circuit to update the photovoltaic grid-connected simulation model; and replace the simulated converter based on the switching transistor equivalent circuit to update the photovoltaic grid-connected simulation model; and replace the simulated inverter based on the three-phase grid-connected inverter circuit to update the photovoltaic grid-connected simulation model.

[0178] In some embodiments, the replacement module 11 is further configured to replace the simulation combiner box based on the forward converter circuit and connect it with other simulation components to update the photovoltaic grid-connected simulation model; the forward converter circuit includes a primary winding, a secondary winding, a magnetic reset winding, and a proportional-integral (PI) controller; run the updated photovoltaic grid-connected simulation model to determine the total current value of the photovoltaic grid-connected simulation model and the branch current value of at least one branch; and determine the control signal of the PI controller based on the total current value, the branch current values ​​of different branches, and the preset reference current value to update the photovoltaic grid-connected simulation model again.

[0179] In some embodiments, the replacement module 11 is further configured to, for each branch, determine the current difference of the branch current based on the difference between the total current value and the branch current value, and select the smallest current difference as the equalization current; and determine the control signal of the PI controller based on the relationship between the equalization current and the preset reference current.

[0180] In some embodiments, the replacement module 11 is further configured to replace the simulated converter based on the equivalent circuit of the switching transistor and connect it with other simulation components to update the photovoltaic grid-connected simulation model; the equivalent circuit of the switching transistor includes a switching transistor; run the updated photovoltaic grid-connected simulation model to determine the voltage change value of the photovoltaic grid-connected simulation model during the sampling period; determine the control strategy of the switching transistor according to the relationship between the voltage change value and the preset voltage threshold to update the photovoltaic grid-connected simulation model again; wherein the control strategy includes: maintaining the disturbance step size of the switching transistor control duty cycle when the voltage change value is equal to the preset voltage threshold; increasing the disturbance step size of the switching transistor control duty cycle when the voltage change value is greater than the preset voltage threshold; and decreasing the disturbance step size of the switching transistor control duty cycle when the voltage change value is less than the preset voltage threshold.

[0181] In some embodiments, the replacement module 11 is further configured to replace the simulated inverter based on the three-phase grid-connected inverter circuit and connect it with other simulation components to update the photovoltaic grid-connected simulation model; run the updated photovoltaic grid-connected simulation model to determine the three-phase voltage values ​​of the three-phase grid-connected inverter circuit; decouple the three-phase voltage values ​​to obtain the target voltage value; and determine the control strategy of the three-phase grid-connected inverter circuit based on the target voltage value and a preset triangular carrier wave to update the photovoltaic grid-connected simulation model again.

[0182] Each module in the aforementioned photovoltaic grid-connected modeling device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the computer device's memory as software, so that the processor can call and execute the operations corresponding to each module.

[0183] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 7 As shown, this computer device includes a processor, memory, input / output interfaces (I / O), and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operating system and computer programs stored in the non-volatile storage media. The database stores data. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network. When the computer program is executed by the processor, it implements a photovoltaic grid-connected modeling method.

[0184] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0185] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0186] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0187] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0188] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0189] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0190] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0191] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A photovoltaic grid-connected modeling method, characterized in that, The method includes: Obtain a photovoltaic grid-connected simulation model; the photovoltaic grid-connected simulation model includes at least one simulation component; the simulation component corresponds to a real component in the photovoltaic network; Based on the preset equivalent circuit of the simulation components, the simulation components in the photovoltaic grid-connected simulation model are replaced to update the photovoltaic grid-connected simulation model. Based on preset illumination rules, the updated photovoltaic grid-connected simulation model is simulated and verified; the illumination rules are to maintain normal illumination for a preset duration and then perform abrupt changes on the normal illumination; the abrupt changes include increasing or decreasing illumination. Determine the grid connection description data of the updated photovoltaic grid-connected simulation model under the condition of sudden change in light intensity; the grid connection description data includes at least one of grid connection current, grid connection voltage and grid connection power; If the grid connection description data is the same as the preset standard description data, the simulation verification of the grid connection simulation model is deemed successful.

2. The method according to claim 1, characterized in that, The simulation components include at least one of simulated photovoltaic cells, simulated combiner boxes, simulated converters, and simulated inverters; the replacement of simulation components in the photovoltaic grid-connected simulation model based on the preset equivalent circuit of the simulation components to update the photovoltaic grid-connected simulation model includes: Based on the equivalent circuit of a photovoltaic cell, the simulated photovoltaic cell is replaced to update the photovoltaic grid-connected simulation model; and, Based on the forward converter circuit, the simulated combiner box is replaced to update the photovoltaic grid-connected simulation model; and, Based on the equivalent circuit of the switching transistor, the simulated converter is replaced to update the photovoltaic grid-connected simulation model; and, The simulated inverter is replaced based on the three-phase grid-connected inverter circuit to update the photovoltaic grid-connected simulation model.

3. The method according to claim 2, characterized in that, The replacement of the simulated combiner box based on the forward converter circuit to update the photovoltaic grid-connected simulation model includes: Based on the forward converter circuit, the simulated combiner box is replaced and connected with other simulated components to update the photovoltaic grid-connected simulation model; the forward converter circuit includes a primary winding, a secondary winding, a magnetic reset winding, and a proportional-integral (PI) controller; Run the updated photovoltaic grid-connected simulation model to determine the total current value and the branch current value of at least one branch of the photovoltaic grid-connected simulation model; Based on the total current value, the branch current values ​​of different branches, and the preset reference current value, the control signal of the PI controller is determined to update the photovoltaic grid-connected simulation model again.

4. The method according to claim 3, characterized in that, The step of determining the control signal for the PI controller based on the total current value, the branch current values ​​of different branches, and the preset reference current includes: For each branch, the current difference of the branch current is determined based on the difference between the total current value and the branch current value, and the minimum current difference is selected as the equalization current. The control signal of the PI controller is determined based on the relationship between the equalization current and the preset reference current.

5. The method according to claim 2, characterized in that, The process of replacing the simulated converter based on the equivalent circuit of the switching transistor and updating the photovoltaic grid-connected simulation model includes: Based on the equivalent circuit of the switching transistor, the simulated converter is replaced and connected with other simulated components to update the photovoltaic grid-connected simulation model; the equivalent circuit of the switching transistor includes a switching transistor; Run the updated photovoltaic grid-connected simulation model to determine the voltage change value of the photovoltaic grid-connected simulation model during the sampling period; Based on the relationship between the voltage change value and the preset voltage threshold, the control strategy of the switching transistor is determined to update the photovoltaic grid-connected simulation model again. The control strategy includes: maintaining the perturbation step size of the switch control duty cycle when the voltage change value is equal to the preset voltage threshold; increasing the perturbation step size of the switch control duty cycle when the voltage change value is greater than the preset voltage threshold; and decreasing the perturbation step size of the switch control duty cycle when the voltage change value is less than the preset voltage threshold.

6. The method according to claim 2, characterized in that, The process of replacing the simulated inverter based on the three-phase grid-connected inverter circuit and updating the photovoltaic grid-connected simulation model includes: Based on the three-phase grid-connected inverter circuit, the simulated inverter is replaced and connected with other simulation components to update the photovoltaic grid-connected simulation model; Run the updated photovoltaic grid-connected simulation model to determine the three-phase voltage values ​​of the three-phase grid-connected inverter circuit; The three-phase voltage values ​​are decoupled to obtain the target voltage value; Based on the target voltage value and the preset triangular carrier wave, the control strategy of the three-phase grid-connected inverter circuit is determined to update the photovoltaic grid-connected simulation model again.

7. A photovoltaic grid-connected modeling device, characterized in that, The device includes: An acquisition module is used to acquire a photovoltaic grid-connected simulation model; the photovoltaic grid-connected simulation model includes at least one simulation component; the simulation component corresponds to a real component in the photovoltaic network; The replacement module is used to replace the simulation components in the photovoltaic grid-connected simulation model based on the preset equivalent circuit of the simulation components, so as to update the photovoltaic grid-connected simulation model. The verification module is used to perform simulation verification on the updated photovoltaic grid-connected simulation model based on a preset illumination rule. The illumination rule is to maintain normal illumination for a preset duration and then perform a sudden change processing on the normal illumination. The sudden change processing includes increasing or decreasing the illumination. The determination module is used to determine the grid connection description data of the updated photovoltaic grid connection simulation model under the condition of sudden change in light intensity, and to determine that the simulation verification of the grid connection simulation model is passed if the grid connection description data is the same as the preset standard description data.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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