A photovoltaic power station model switching method and device and computer storage medium

Abstract

This invention discloses a method, device, and computer storage medium for switching photovoltaic (PV) power plant models. It establishes models of varying complexity for the PV array, chopper circuit, converter, and filter circuit of the PV power plant, and provides discriminative features to distinguish the operating states of the PV power plant, classifying and analyzing these states. Considering the uncertainties in the operating conditions of the PV power plant, it identifies the current operating state and performs corresponding switching based on the proposed model switching strategy. This invention improves simulation speed and efficiency while maintaining simulation accuracy, effectively enabling rapid overall simulation of PV power plants.

Description

Technical Field

[0001] This invention relates to a method, device, and computer storage medium for switching photovoltaic power plant models, belonging to the field of photovoltaic power plant model switching simulation technology. Background Technology

[0002] With the increasing global demand for renewable energy, photovoltaic (PV) power plants have attracted much attention as a sustainable and clean energy solution. To more effectively plan, operate, and optimize PV power plants, researchers in this industry face the challenge of developing various models to simulate and analyze the performance and behavior of PV power plants. Simplified models and detailed models are two main modeling methods used to simulate the operating conditions of PV power plants under different circumstances.

[0003] Simplified models are generally suitable for preliminary assessments and rapid decision-making. Although their accuracy is relatively low, they are computationally efficient and valuable for estimating large-scale operating conditions. Detailed models are better suited for precise performance analysis and power plant optimization. Their higher complexity allows for more accurate simulation of the dynamic behavior of various components of a photovoltaic power plant under different conditions, but they require longer computation times and more computational resources. When facing complex operating conditions, choosing an appropriate model can significantly reduce the time and resources required for simulation while maintaining accuracy. Summary of the Invention

[0004] This invention addresses the problems in existing technologies by providing a method, device, and computer storage medium for switching photovoltaic power plant models. It categorizes and analyzes the operating status of photovoltaic power plants, selects appropriate models for simulation under different operating conditions, and achieves the goal of balancing the speed and accuracy of rapid simulation of photovoltaic power plants.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for switching photovoltaic power plant models includes the following steps:

[0007] Establish a photovoltaic power plant model, including simplified and detailed models of photovoltaic arrays, chopper circuits, inverters, and filters;

[0008] Establish discriminative features to distinguish the operating status of photovoltaic power plants based on the operating status of photovoltaic arrays;

[0009] Identify the current operating status of the photovoltaic power station based on discriminant features;

[0010] Based on the current operating status of the photovoltaic power station, a switching strategy for the photovoltaic power station model is proposed, and the simplified model and detailed model are switched accordingly.

[0011] As an improvement to the present invention, the simplified model of the photovoltaic array is as follows:

[0012]

[0013] Where M = U PV / N S +I PV R s / N P ;I PV U is the output current of the photovoltaic array. PV I is the output voltage of the photovoltaic array. ph Photocurrent; N S N represents the number of modules connected in series in the photovoltaic array. P I represents the number of modules connected in parallel in the photovoltaic array. d This represents the reverse saturation leakage current; R sh R is the equivalent parallel impedance; s The equivalent series impedance is T; the temperature is A; the ideality factor of the diode is k; and the Boltzmann constant is k. The detailed model of the photovoltaic array is consistent with the simplified model.

[0014] As an improvement to this invention, the chopper circuit adopts a Boost circuit, and its simplified model is as follows:

[0015] When the IGBT is turned on, the voltage transformation formula is:

[0016]

[0017] When the IGBT is turned off, the voltage transformation formula is:

[0018]

[0019] Among them, U PV i is the output voltage of the photovoltaic array; L U is the current in the inductor; dc i is the output voltage of the Boost circuit; dc L represents the output current; C represents the inductor and capacitor in the chopper circuit.

[0020] The detailed model of the chopper circuit is as follows:

[0021] When the IGBT is turned on, the inductor charges and the capacitor discharges. The voltage transformation formula is:

[0022]

[0023] When the IGBT is turned off, the inductor discharges and the capacitor charges. The voltage transformation formula is:

[0024]

[0025] Among them, U PV U is the output voltage of the photovoltaic array. dc i is the output voltage of the chopper circuit; L C1 is the current in the inductor; C2 is the output capacitor of the photovoltaic array; L and C2 are the inductor and capacitor of the chopper circuit; i L i represents the current in the inductor; PV I is the output current of the photovoltaic array. dc This is the output current of the chopper circuit.

[0026] As an improvement to this invention, SPWM modulation technology is adopted, and the simplified model of the inverter is as follows:

[0027]

[0028] Among them, U m I is the inverter output voltage; E is the grid connection point voltage; I L U is the inverter output current; c L is the voltage across the filter capacitor; L is the inductance of the filter circuit; I is the output current; R is the filter resistance.

[0029] Using a single-phase inverter for simplified analysis, the detailed model of the inverter is as follows:

[0030]

[0031] Wherein, G(t) is a gate function, which has a value of 1 when the PWM signal controls the inverter bridge of phase A to turn on, and a value of -1 when phase B is turned on; I AC1 U is the output current at the inverter's output terminal; AC I is the output voltage at the inverter's output terminal. dc Input current to the inverter input terminal; U dc This is the input voltage at the inverter's input terminal.

[0032] As an improvement to this invention, the mathematical model of the filter is considered as a superposition of sine waves of different frequencies, and its simplified model is as follows:

[0033]

[0034] in, The fundamental voltage, The voltage is the harmonic voltage; R is the filter input resistance; x L For fundamental impedance, x Ln For harmonic reactance; x C For fundamental frequency capacitance, x Cn For harmonic capacitance; For grid voltage

[0035] The LCL filter is used, and its detailed model is as follows:

[0036]

[0037] Where L and C are the inductance and capacitance of the filter circuit, respectively; U C I is the capacitor voltage; L U is the inductor current on the left; E is the mains voltage; U AC I is the voltage at the inverter output terminal; I is the final output current of the inverter; R is the series impedance of the inductor on the left.

[0038] As an improvement of the present invention, the operating status of the photovoltaic power station depends on the operating status of the photovoltaic array. The operating status is divided into normal operating status and abnormal status, which is determined by photovoltaic-related factors and array operation-related factors. The operating status serves as the basis for switching the photovoltaic power station model.

[0039] For photovoltaic-related factors, the following rules are used to determine the light conditions and temperature conditions:

[0040] |ΔS|≤ΔS set (10)

[0041] |ΔT|≤ΔT set (11)

[0042] For factors related to array operation, the photovoltaic array output voltage determination rule and the photovoltaic array output current determination rule are adopted:

[0043] |ΔU PV |≤ΔU set (12)

[0044] |ΔI PV |≤ΔI set (13)

[0045] If either the light condition determination rule or the temperature condition determination rule is not met, and neither the photovoltaic array output voltage determination rule nor the photovoltaic array output current determination rule is met, it is an abnormal state; otherwise, it is a normal state.

[0046] Where ΔS is the change in illumination, ΔS set ΔT is the threshold for light intensity change; ΔT is the temperature change value. set The temperature change threshold; ΔU PV The change in output voltage of the photovoltaic array, ΔU set ΔI is the threshold value for the output voltage change of the photovoltaic array. PV The change in output current of the photovoltaic array, ΔI set This is the threshold value for the change in output current of the photovoltaic array.

[0047] As an improvement of the present invention, the discrimination features are ΔS, ΔT, ΔU, and ΔI, respectively.

[0048] As an improvement of the present invention, the identification of the current operating status of the photovoltaic power station includes:

[0049] The photovoltaic power station is initially set to operate normally. Subsequently, if the photovoltaic array experiences abnormal operating conditions, the current operating status of the photovoltaic power station is determined based on the rules for judging the illumination and temperature status, as well as the rules for judging the output voltage and output current of the photovoltaic array.

[0050] As an improvement to the present invention, the switching strategy of the photovoltaic power station model includes:

[0051] Based on the established simplified and detailed models, the photovoltaic power station model is switched according to the operating status; the low complexity of the simplified model facilitates efficient calculation and preliminary evaluation, while the high precision of the detailed model facilitates accurate simulation of the dynamic behavior of the photovoltaic power station.

[0052] When the photovoltaic power station was in normal operation at the previous moment, it was in a simplified model. If the photovoltaic power station experienced an anomaly at the current sampling moment, it would switch from the simplified model to the detailed model. If the photovoltaic power station was in normal operation at the current sampling moment, it would remain in the simplified model.

[0053] When the photovoltaic power station was in an abnormal state at the previous moment, the photovoltaic power station was in a detailed model. If the photovoltaic power station is in an abnormal state at the current sampling moment, the photovoltaic power station will maintain the detailed model; if the photovoltaic power station is in a normal operating state at the current sampling moment, the photovoltaic power station will switch to a simplified model.

[0054] A multi-granularity model switching device for distributed photovoltaic power plants includes:

[0055] The model building module is used to build photovoltaic power plant models, including simplified and detailed models of photovoltaic arrays, chopper circuits, inverters, and filters.

[0056] The discriminant feature establishment module is used to establish discriminant features that distinguish the operating status of photovoltaic power plants based on the operating status of the photovoltaic array;

[0057] The operation status determination module is used to identify the current operation status of the photovoltaic power station based on the determination features;

[0058] The model switching module is used to propose a switching strategy for the photovoltaic power station model based on the current operating status of the photovoltaic power station, and to perform the corresponding switching.

[0059] A computer storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described above.

[0060] An electronic device includes a memory and one or more processors, the memory storing one or more programs; when executed by the one or more processors, the one or more programs implement the method described above.

[0061] The beneficial effects of this invention are as follows: Compared with the prior art, this invention provides a method for switching photovoltaic power plant models. This method establishes simplified and detailed models for each unit of the photovoltaic power plant, while taking into account the uncertainty of the photovoltaic power plant's operating conditions. It switches the models accordingly based on the operating status, thus achieving a balance between the speed and accuracy requirements of rapid simulation of photovoltaic power plants. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0063] Figure 1 This is a flowchart of a photovoltaic power station model switching method according to the present invention;

[0064] Figure 2 This is a diagram of the output voltage of the photovoltaic array in Embodiment 1 of the present invention;

[0065] Figure 3 This is the output current diagram of the photovoltaic array in Embodiment 1 of the present invention;

[0066] Figure 4 This is a diagram of the output voltage of the photovoltaic array in Embodiment 2 of the present invention;

[0067] Figure 5 This is the output current diagram of the photovoltaic array in Embodiment 2 of the present invention. Detailed Implementation

[0068] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] Example 1:

[0070] This embodiment constructs a photovoltaic power station that includes a simplified model, a detailed model, and a switching model, based on the simplified and detailed models of the photovoltaic power station described above. The simulation duration is set to 1.5 seconds, and the initial irradiance is 1000 W / m². 2 The temperature is set to 25℃, ΔSset The value is 200, ΔT set The value is 2, ΔI set The value is 2, ΔU set The value is 2, and an illumination perturbation is applied at 1 second until the simulation ends. The illumination intensity is 1500 W / m. 2 Temperature changes are not considered in the short term. This example uses three models for comparison: a simple model only, a detailed model only, and a switching model. When using the switching model, the initial model is the detailed model, and the switching delay is 0.1s. The output voltage and current diagrams of the photovoltaic array in this example are shown below. Figure 1 , Figure 2 As shown in Table 1 below, the results of Example 1 are analyzed and compared.

[0071] Table 1. Simulation Results Analysis of Example 1

[0072]

[0073] Example 2:

[0074] This embodiment constructs a photovoltaic power station as described in the previous embodiment, based on the simplified and detailed models of the photovoltaic power station. The simulation duration is set to 1.5s, and ΔS... set The value is 200, ΔT set The value is 2, ΔI set The value is 2, ΔU set The value is 2, and the light intensity is set to 1000 W / m². 2 The temperature is set to 25°C, and the difference from the previous embodiment is that an array failure is simulated at 1 second. PV At this point, the voltage drops to 125V, and the light intensity increases to 1500W / m². 2 The simulation continues until its end, without considering temperature changes in the short term. This example uses three models for comparison: a simple model only, a detailed model only, and a switched model. When using the switched model, the initial model is the detailed model, and the switching delay is 0.1 seconds. The output voltage and current diagrams of the photovoltaic array in this example are shown below. Figure 4 , Figure 5 As shown in Table 2 below, the results of Example 2 are analyzed and compared.

[0075] Table 2 Simulation Results Analysis Table for Example 2

[0076]

[0077] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above examples; the examples and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A photovoltaic power plant model switching method, characterized by, Includes the following steps: Establish a photovoltaic power plant model, including simplified and detailed models of photovoltaic arrays, chopper circuits, inverters, and filters; Establish discriminative features to distinguish the operating status of photovoltaic power plants based on the operating status of photovoltaic arrays; Identify the current operating status of the photovoltaic power station based on discriminant features; Based on the current operating status of the photovoltaic power station, a switching strategy for the photovoltaic power station model is proposed, and the simplified model and detailed model are switched accordingly. The operating status of the photovoltaic power station depends on the operating status of the photovoltaic array. The operating status is divided into normal operating status and abnormal status, which is determined by photovoltaic-related factors and array operation-related factors. The operating status serves as the basis for switching the photovoltaic power station model. For photovoltaic-related factors, the following rules are used to determine the light conditions and temperature conditions: （10） （11） For factors related to array operation, the photovoltaic array output voltage determination rule and the photovoltaic array output current determination rule are adopted: （12） （13） If either the light condition determination rule or the temperature condition determination rule is not met, and neither the photovoltaic array output voltage determination rule nor the photovoltaic array output current determination rule is met, it is an abnormal state; otherwise, it is a normal state. wherein is a light change value, is a light change threshold value; is a temperature change value, is a temperature change threshold value; is a photovoltaic array output voltage change value, is a photovoltaic array output voltage change threshold value; is a photovoltaic array output current change value, is a photovoltaic array output current change threshold value; the discrimination features are respectively , , , .

2. The photovoltaic power plant model switching method as described in claim 1, characterized in that, The simplified model of the photovoltaic array is as follows: （1） in, ; Output current for the photovoltaic array; This refers to the output voltage of the photovoltaic array. Photocurrent; This represents the number of modules connected in series in the photovoltaic array. This represents the number of modules connected in parallel in the photovoltaic array. This is the reverse saturation leakage current; This is the equivalent parallel impedance; This is the equivalent series impedance; For temperature; The ideal factor for a diode; It is the Boltzmann constant; the detailed model of the photovoltaic array is consistent with the simplified model.

3. The photovoltaic power plant model switching method as described in claim 1, characterized in that, The simplified model of the chopper circuit is as follows: When the IGBT is turned on, the voltage transformation formula is: （2） When the IGBT is turned off, the voltage transformation formula is: （3） in, This refers to the output voltage of the photovoltaic array. The current in the inductor; This refers to the output voltage of the Boost circuit. For output current; , For inductors and capacitors in a chopper circuit; The detailed model of the chopper circuit is as follows: When the IGBT is turned on, the inductor charges and the capacitor discharges. The voltage transformation formula is: （4） When the IGBT is turned off, the inductor discharges and the capacitor charges. The voltage transformation formula is: （5） in, This refers to the output voltage of the photovoltaic array. This is the output voltage of the chopper circuit; The current in the inductor; For the output side capacitor of the photovoltaic array; , The inductors and capacitors are for the chopper circuit; The current in the inductor; Output current for the photovoltaic array; This is the output current of the chopper circuit.

4. The photovoltaic power plant model switching method as described in claim 1, characterized in that, The simplified model of the inverter is as follows: （6） in, This refers to the inverter output voltage. This refers to the voltage at the grid connection point. This is the inverter output current. This refers to the voltage across the filter capacitor. Inductance for the filter circuit; For output current; For filter resistors; The detailed model of the inverter is as follows: （7） Wherein, G(t) is a gate function, which has a value of 1 when the PWM signal controls the inverter bridge of phase A to turn on, and a value of -1 when phase B is turned on; This refers to the output current at the inverter's output terminal. This refers to the output voltage at the inverter's output terminal. Input current to the inverter inlet terminal; This is the input voltage at the inverter's input terminal.

5. The photovoltaic power plant model switching method as described in claim 1, characterized in that, The simplified model of the filter is as follows: （8） in, The fundamental voltage, Harmonic voltage; This is the input resistance of the filter; For fundamental impedance, For harmonic reactance; For fundamental frequency capacitance, For harmonic capacitance; For grid voltage The detailed model of the filter is as follows: （9） in, , These are the inductor and capacitor of the filter circuit, respectively. This is the capacitor voltage; The current is the inductor current on the left side; This refers to the grid voltage. This is the voltage at the inverter output terminal; This is the final output current of the inverter; The series impedance of the inductor on the left is shown.

6. The photovoltaic power plant model switching method as described in claim 1, characterized in that, The identification of the current operating status of the photovoltaic power station includes: The photovoltaic power station is initially set to operate normally. Subsequently, if the photovoltaic array experiences abnormal operating conditions, the current operating status of the photovoltaic power station is determined based on the rules for judging the illumination and temperature status and the rules for judging the output voltage and output current of the photovoltaic array. The switching strategy for the photovoltaic power plant model includes: The simplified model and the detailed model are switched according to the established simplified model and the running status; When the photovoltaic power station was in normal operation at the previous moment, the photovoltaic power station was in a simplified model. If the photovoltaic power station experienced an anomaly at the current sampling moment, the photovoltaic power station switched from the simplified model to the detailed model; if the photovoltaic power station was in normal operation at the current sampling moment, the photovoltaic power station remained in the simplified model. When the photovoltaic power station was in an abnormal state at the previous moment, the photovoltaic power station was in a detailed model. If the photovoltaic power station is in an abnormal state at the current sampling moment, the photovoltaic power station will maintain the detailed model; if the photovoltaic power station is in a normal operating state at the current sampling moment, the photovoltaic power station will switch to a simplified model.

7. A photovoltaic power station model switching device, characterized in that, include: The model building module is used to build photovoltaic power plant models, including simplified and detailed models of photovoltaic arrays, chopper circuits, inverters, and filters. The discriminant feature establishment module is used to establish discriminant features that distinguish the operating status of photovoltaic power plants based on the operating status of the photovoltaic array; The operation status determination module is used to identify the current operation status of the photovoltaic power station based on the determination features; The model switching module is used to propose a switching strategy for the photovoltaic power station model based on the current operating status of the photovoltaic power station and to perform the corresponding switching. The operating status of the photovoltaic power station depends on the operating status of the photovoltaic array. The operating status is divided into normal operating status and abnormal status, which is determined by photovoltaic-related factors and array operation-related factors. The operating status serves as the basis for switching the photovoltaic power station model. For photovoltaic-related factors, the following rules are used to determine the light conditions and temperature conditions: （10） （11） For factors related to array operation, the photovoltaic array output voltage determination rule and the photovoltaic array output current determination rule are adopted: （12） （13） If either the light condition determination rule or the temperature condition determination rule is not met, and neither the photovoltaic array output voltage determination rule nor the photovoltaic array output current determination rule is met, it is an abnormal state; otherwise, it is a normal state. in, This represents the change in illumination. The threshold for changes in illumination; This represents the temperature change value. The temperature change threshold; This represents the change in output voltage of the photovoltaic array. The threshold value for the output voltage change of the photovoltaic array; This represents the change in output current of the photovoltaic array. The threshold for the change in output current of the photovoltaic array; the discrimination features are respectively , , , .

8. A computer storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the steps of the method as described in any one of claims 1 to 6.

9. An electronic device, characterized in that, The method includes a memory and one or more processors, the memory being used to store one or more programs; when the one or more programs are executed by the one or more processors, they implement the method as described in any one of claims 1 to 6.

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