CN116131347A - Intelligent control-based photovoltaic grid-connected inverter and photovoltaic grid-connected system - Google Patents
Intelligent control-based photovoltaic grid-connected inverter and photovoltaic grid-connected system Download PDFInfo
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- CN116131347A CN116131347A CN202310388693.5A CN202310388693A CN116131347A CN 116131347 A CN116131347 A CN 116131347A CN 202310388693 A CN202310388693 A CN 202310388693A CN 116131347 A CN116131347 A CN 116131347A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/004—Generation forecast, e.g. methods or systems for forecasting future energy generation
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
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Abstract
The invention relates to a photovoltaic grid-connected inverter and a photovoltaic grid-connected system based on intelligent control, which relate to the field of general control or regulation systems, wherein the inverter comprises: the photovoltaic grid-connected inverter device is used for converting direct current from a junction box into alternating current, and the junction box is connected with a plurality of photovoltaic electric plates; and the boosting control device is used for starting the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than the set voltage threshold value, and connecting the alternating current output by the alternating current transformer into a power supply grid. The present invention is able to analyze whether or not a field boosting process needs to be performed based on a determined specific voltage, and select a specific type of ac transformer that performs boosting when the analysis is needed.
Description
Technical Field
The invention relates to the field of general control or regulation systems, in particular to a photovoltaic grid-connected inverter and a photovoltaic grid-connected system based on intelligent control.
Background
The photovoltaic power generation system is mainly a direct current system, namely, the storage battery is charged based on the electric energy converted by the received solar energy, and then the storage battery directly supplies power to each power utilization load in the power grid, for example, a solar energy user lighting system which is more used in northwest China and a microwave station power supply system which is far away from the power grid are both direct current systems.
In a photovoltaic power generation system, a photovoltaic grid-connected inverter converts direct current into alternating current, and if the direct current voltage is lower, the direct current voltage needs to be boosted by an alternating current transformer, so that standard alternating current voltage and frequency are obtained. Although the photovoltaic grid-connected inverter can invert various direct-current voltages to obtain 220V standard voltage, if the direct-current voltage is too low, the inversion affects the conversion efficiency. For example, if the dc voltage received by the photovoltaic grid-connected inverter is high, such as 36V or more, the ac output end of the photovoltaic grid-connected inverter can reach 220V without voltage boosting of the transformer under the condition that conversion efficiency is not affected, however, when the dc voltage received by the photovoltaic grid-connected inverter is low, such as 12V and 24V, a voltage boosting circuit based on the transformer must be designed.
For example, a control method for suppressing the output direct current component of a photovoltaic grid-connected inverter is provided by Chinese patent publication No. CN101577434A, belongs to the technical field of inverter grid-connected control, and is provided for solving the problems of high cost, large volume, high power consumption and high price of a high-capacity blocking capacitor system by adopting a power frequency transformer in suppressing the output current direct current component of the photovoltaic grid-connected inverter. The method samples grid-connected current, acquires current direct current components contained in the grid-connected current, inhibits the current direct current components by two parts, and comprises the first part: introducing a direct current component caused by sampling errors into grid-connected current setting in a negative feedback mode, wherein the second part is as follows: the average direct current component of the modulation signal of each switching period in the previous power frequency period is obtained, the direct current component caused by unbalanced pulse width is formed after PI adjustment, and the direct current component is introduced into the primary modulation signal in a negative feedback mode. Through the two parts, a modulation signal for suppressing the direct current component is finally formed, and PWM driving signals for driving four switching tubes of the photovoltaic grid-connected inverter are obtained.
For example, the maximum power tracking method of the photovoltaic grid-connected system proposed by the Chinese patent publication No. CN101699696A comprises the following steps that firstly, the output alternating current of a grid-connected inverter is sampled through an alternating current sensor; step two, calculating the average value of half periods according to the sampling result and the corresponding mains frequency; thirdly, converting the calculated average value of the alternating current into an output current effective value; and fourthly, converting the output alternating current effective value into the direct current value displayed and input by the solar panel by utilizing the small change of the conversion efficiency of the grid-connected inverter, and tracking the maximum power point by utilizing a common climbing method. Through reasonable control of the grid-connected inverter, the generated energy of the battery plate is fully utilized, so that the output power of the battery plate reaches the maximum, and the tracking of the maximum power point is realized.
However, in the above prior art, since the specific voltage of the power supply dc voltage input to the photovoltaic grid-connected inverter at a certain future time of the photovoltaic power supply system cannot be predicted in advance, it cannot be determined whether the specific voltage is too small to be inverted to the standard voltage, which affects the conversion efficiency, so that the inversion mode at each time is changed along with the specific voltage of the power supply dc voltage, and this change has serious hysteresis, and more importantly, the forced inversion to the standard voltage under the condition that some specific voltages are too small can seriously affect the conversion efficiency.
Disclosure of Invention
In order to solve the above problems in the prior art, the present invention provides a photovoltaic grid-connected inverter and a photovoltaic grid-connected system based on intelligent control, which can determine in advance a specific voltage of a power supply direct current input to the photovoltaic grid-connected inverter at a certain moment in the future of a photovoltaic power supply system, analyze whether to perform field boosting processing based on the determined specific voltage, and select a specific type of an ac transformer performing boosting when the analysis is needed, thereby avoiding an excessively lagging inversion process and avoiding a serious influence on the power conversion efficiency of a power grid due to forced inversion to a standard voltage.
According to a first aspect of the present invention, there is provided an intelligent control-based photovoltaic grid-connected inverter comprising:
the photovoltaic grid-connected inverter device is used for being connected with the combiner box and converting direct current from the combiner box into alternating current, the combiner box is connected with a plurality of photovoltaic electric plates, the plurality of photovoltaic electric plates are located in the same area, and the maximum output power of the plurality of photovoltaic electric plates is the same;
the boost control device is connected with the photovoltaic grid-connected inverter device and is used for starting the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device to obtain and output alternating current equal to the standard alternating current voltage when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than a set voltage threshold value and the next moment comes, and connecting the alternating current output by the alternating current transformer into a power supply grid;
the prediction processing device is used for intelligently predicting the direct current voltage of the direct current of the combiner box corresponding to the next moment based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the combiner box corresponding to the plurality of moments before the next moment, wherein the plurality of moments before the next moment are equal to each other in a two-to-two interval on a time axis and form a complete duration;
the customized training equipment is connected with the prediction processing equipment and is used for sending the cyclic neural network after the repeated training of the preset training total number to the prediction processing equipment for use;
the boost control device is further used for disabling the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device to obtain and output alternating current equal to the standard alternating current voltage when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is equal to or higher than a set voltage threshold value and directly connecting the alternating current output by the photovoltaic grid-connected inverter device into a power supply grid;
the method for intelligently predicting the direct current voltage of the direct current of the combiner box corresponding to the next moment based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the combiner box corresponding to the plurality of moments before the next moment further comprises: and adopting a circulating neural network to intelligently predict the direct current voltage of the direct current of the junction box corresponding to the next moment based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the junction box corresponding to the plurality of moments before the next moment.
According to a second aspect of the present invention, there is provided a photovoltaic grid-connected system comprising a combiner box, a plurality of photovoltaic panels and an intelligent control-based photovoltaic grid-connected inverter according to the first aspect of the present invention.
Compared with the prior art, the invention at least needs to have the following important inventive concepts and technical effects:
firstly, introducing an intelligent prediction mechanism for photovoltaic grid-connected inversion equipment, and intelligently predicting direct-current voltage of direct-current of a combiner box corresponding to the next moment based on average sunlight duration of the current season of the same region where a plurality of photovoltaic electric plates are in, maximum output power of the photovoltaic electric plates and a plurality of direct-current voltages of direct-current of the combiner box corresponding to a plurality of moments before the next moment;
secondly, when the direct current voltage of the direct current of the combiner box corresponding to the predicted next moment is too low, selecting an alternating current transformer matched with the direct current voltage to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device, so that the standard grid-connected voltage is obtained while the conversion efficiency is not affected;
thirdly, the intelligent prediction mechanism is based on a cyclic neural network after a plurality of times of training of the preset training total number, and the value of the preset training total number and the average sunlight time of the current season in the same area where the plurality of photovoltaic panels are located grow into a monotonic forward association relationship, so that the reliability and pertinence of the intelligent prediction mechanism are ensured;
finally, in the input content of the intelligent prediction mechanism, the number of the selected times before the next time is in direct proportion to the number of the photovoltaic electric plates connected with the combiner box, so that the customization of the intelligent prediction mechanism under different photovoltaic power supply scenes is completed.
Drawings
Embodiments of the present invention will be described below with reference to the accompanying drawings, in which:
fig. 1 is a technical flowchart of a photovoltaic grid-connected inverter and a photovoltaic grid-connected system based on intelligent control according to the invention.
Fig. 2 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 1 of the present invention.
Fig. 3 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 2 of the present invention.
Fig. 4 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 3 of the present invention.
Fig. 5 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 4 of the present invention.
Fig. 6 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 5 of the present invention.
Fig. 7 is a schematic structural diagram of a photovoltaic grid-connected system according to embodiment 6 of the present invention.
Detailed Description
As shown in fig. 1, a technical flowchart of the intelligent control-based photovoltaic grid-connected inverter and the intelligent control-based photovoltaic grid-connected system is provided.
As shown in fig. 1, the specific technical process of the present invention is as follows:
firstly, building a hardware foundation of a photovoltaic grid-connected system with a set structure, wherein the photovoltaic grid-connected system comprises a plurality of photovoltaic panels, a combiner box, photovoltaic grid-connected inverter equipment and an alternating current transformer which may be needed, the photovoltaic grid-connected system is used for providing alternating current power supply for a plurality of loads of a power grid which is supplied with power, and the set structure is based on the number of the photovoltaic panels, average sunlight duration of a region where the photovoltaic panels are located and maximum output power of each photovoltaic panel;
illustratively, as shown in fig. 1, the plurality of photovoltaic panels are photovoltaic panel 1, photovoltaic panel 2, …, respectively, photovoltaic panel N, where N is a natural number greater than 1;
secondly, establishing a corresponding intelligent prediction model aiming at a photovoltaic grid-connected system with a set structure, wherein each item of input of the intelligent prediction model is an average sunlight duration of the current season of the same region in which a plurality of photovoltaic electric plates for power supply are located, a maximum output power of the photovoltaic electric plates and a plurality of direct current voltages of direct current of a combiner box respectively corresponding to a plurality of moments before a certain moment in the future, and the output of the intelligent prediction model is the direct current voltage of the direct current of the combiner box corresponding to the certain moment in the future to serve as prediction data;
and thirdly, determining whether field boosting processing is required to be executed or not based on the prediction data, and selecting a specific type of alternating current transformer for executing boosting when analysis is required, so that the instantaneity of the inversion processing process is improved, and the power conversion efficiency of the power grid is ensured.
The key points of the invention are as follows: and (3) building different intelligent prediction models corresponding to the photovoltaic grid-connected systems with different setting structures, and executing prediction of direct-current voltage of direct current of a combiner box corresponding to a certain moment in the future based on the built intelligent prediction models, so that important reference information is provided for a subsequent alternating-current transformation strategy.
The intelligent control-based photovoltaic grid-connected inverter and the intelligent control-based photovoltaic grid-connected system of the present invention will be specifically described in the following by way of example.
Example 1
Fig. 2 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 1 of the present invention.
As shown in fig. 2, the intelligent control-based photovoltaic grid-connected inverter comprises the following components:
the photovoltaic grid-connected inverter device is used for being connected with the combiner box and converting direct current from the combiner box into alternating current, the combiner box is connected with a plurality of photovoltaic electric plates, the plurality of photovoltaic electric plates are located in the same area, and the maximum output power of the plurality of photovoltaic electric plates is the same;
for example, the plurality of photovoltaic panels may be the same model of photovoltaic panel to ensure that the maximum output power of the plurality of photovoltaic panels is the same;
meanwhile, the plurality of photovoltaic electric plates can be uniformly distributed in the same area so as to ensure that the average sunlight duration of the plurality of photovoltaic electric plates is the same every day;
the boost control device is connected with the photovoltaic grid-connected inverter device and is used for starting the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device to obtain and output alternating current equal to the standard alternating current voltage when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than a set voltage threshold value and the next moment comes, and connecting the alternating current output by the alternating current transformer into a power supply grid;
for the photovoltaic grid-connected inverter device, various values of direct current voltages can be subjected to inversion conversion to output alternating current equal to standard alternating current voltage, however, the conversion efficiency is seriously affected by the conversion of the direct current voltage with an excessively low value into the alternating current with the standard alternating current voltage, so that a large amount of power of a power grid is wasted, therefore, the lower direct current voltage lower than a set voltage threshold value needs to be subjected to inversion conversion through the photovoltaic grid-connected inverter device to obtain alternating current lower than the standard alternating current voltage, and then the obtained alternating current is boosted by adopting an alternating current transformer of a corresponding type to obtain alternating current equal to the standard alternating current voltage and used for power supply of the power grid;
illustratively, the corresponding type of ac transformer is mainly represented by a primary coil and a secondary coil having different turns ratios for different types of ac transformers;
obviously, if the photovoltaic grid-connected inverter equipment receives a direct-current voltage with a higher value at a certain moment, the follow-up boosting operation is not needed, a follow-up alternating-current transformer is not needed, and the photovoltaic grid-connected inverter equipment directly converts the direct-current voltage into a standard alternating-current voltage;
the prediction processing device is used for intelligently predicting the direct current voltage of the direct current of the combiner box corresponding to the next moment based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the combiner box corresponding to the plurality of moments before the next moment, wherein the plurality of moments before the next moment are equal to each other in a two-to-two interval on a time axis and form a complete duration;
illustratively, the intervals between the times before the next time and the next time on the time axis are 2 minutes;
the customized training equipment is connected with the prediction processing equipment and is used for sending the cyclic neural network after the repeated training of the preset training total number to the prediction processing equipment for use;
the boost control device is further used for disabling the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device to obtain and output alternating current equal to the standard alternating current voltage when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is equal to or higher than a set voltage threshold value and directly connecting the alternating current output by the photovoltaic grid-connected inverter device into a power supply grid;
the method for intelligently predicting the direct current voltage of the direct current of the combiner box corresponding to the next moment based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the combiner box corresponding to the plurality of moments before the next moment further comprises: a circulating neural network is adopted to intelligently predict the direct current voltage of the direct current of the corresponding junction box at the next moment based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the junction box respectively corresponding to a plurality of moments before the next moment;
the intelligent prediction of the direct current voltage of the direct current of the combiner box corresponding to the next moment based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the combiner box corresponding to the plurality of moments before the next moment comprises: the number of the selected times before the next time is proportional to the number of the photovoltaic electric plates connected with the junction box;
illustratively, the number of times before the selected next time is proportional to the number of photovoltaic panels connected to the header box comprises: the number of the plurality of photovoltaic panels connected by the combiner box is 10 when the number of the plurality of photovoltaic panels connected by the combiner box is 100, the number of the plurality of photovoltaic panels connected by the combiner box is 20 when the number of the plurality of photovoltaic panels connected by the combiner box is 200, the number of the plurality of photovoltaic panels connected by the combiner box is 400, the number of the plurality of times before the selected next time is 40, and the number of the plurality of photovoltaic panels connected by the combiner box is 80 when the number of the plurality of photovoltaic panels connected by the combiner box is 800.
Example 2
Fig. 3 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 2 of the present invention.
As shown in fig. 3, unlike the embodiment in fig. 2, the intelligent control-based photovoltaic grid-connected inverter further includes the following components:
the information storage device is connected with the customized training device and used for storing various network parameters of the cyclic neural network after the repeated training of the preset training total number;
the network parameters are used for representing the corresponding cyclic neural network after multiple training which completes the preset training total number.
Example 3
Fig. 4 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 3 of the present invention.
As shown in fig. 4, unlike the embodiment in fig. 2, the intelligent control-based photovoltaic grid-connected inverter further includes the following components:
an ac transformer array comprising a plurality of ac transformers, each ac transformer having a primary coil and a secondary coil of different turns ratio;
the alternating current transformer array is connected with the boosting control equipment and used for providing an activated alternating current transformer for the boosting control equipment.
Example 4
Fig. 5 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 4 of the present invention.
As shown in fig. 5, unlike the embodiment in fig. 2, the intelligent control-based photovoltaic grid-connected inverter further includes the following components:
the content display device is connected with the boost control equipment and used for displaying the type information of the alternating-current transformer started by the boost control equipment in real time;
the content display device is, for example, an LED display array, an LCD display array or a liquid crystal display screen.
Example 5
Fig. 6 is a schematic structural diagram of a photovoltaic grid-connected inverter based on intelligent control according to embodiment 5 of the present invention.
As shown in fig. 6, unlike the embodiment in fig. 2, the intelligent control-based photovoltaic grid-connected inverter further includes the following components:
the alternating current control cabinet is used for accommodating the photovoltaic grid-connected inversion equipment, the boosting control equipment, the prediction processing equipment and the customized training equipment;
the alternating current control cabinet is internally provided with a power supply for respectively providing power supply operation for the photovoltaic grid-connected inverter equipment, the boost control equipment, the prediction processing equipment and the customized training equipment;
the alternating current control cabinet is internally provided with a fault recording mechanism which is used for respectively providing fault recording operation for the photovoltaic grid-connected inverter equipment, the boost control equipment, the prediction processing equipment and the custom training equipment.
In an intelligent control-based photovoltaic grid-connected inverter according to any embodiment of the present invention:
the method for intelligently predicting the direct current voltage of the direct current of the junction box corresponding to the next moment by adopting the cyclic neural network based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the junction box corresponding to the plurality of moments before the next moment comprises the following steps: taking the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and a plurality of direct current voltages of direct current of the combiner boxes corresponding to a plurality of moments before the next moment as each input data of the circulating neural network, and operating the circulating neural network to obtain the direct current voltage of the direct current of the combiner boxes corresponding to the next moment output by the circulating neural network;
the method for obtaining the direct current voltage of the combiner box corresponding to the next moment output by the circulating neural network comprises the following steps of: before the average sunlight duration of the current season in the same region where the plurality of photovoltaic panels are located, the maximum output power and a plurality of direct current voltages of direct current of the combiner boxes respectively corresponding to a plurality of moments before the next moment are input as respective input data to the cyclic neural network, respectively performing binary value conversion on the average sunlight duration of the current season in the same region where the plurality of photovoltaic panels are located, the maximum output power and the plurality of direct current voltages of direct current of the combiner boxes respectively corresponding to a plurality of moments before the next moment;
the method for obtaining the direct current voltage of the junction box corresponding to the next moment output by the circulating neural network further comprises the steps of taking the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the junction box corresponding to the plurality of moments before the next moment as the input data of the circulating neural network, and operating the circulating neural network to obtain the direct current voltage of the direct current of the junction box corresponding to the next moment output by the circulating neural network: and the obtained direct current voltage of the direct current of the combiner box corresponding to the next moment output by the cyclic neural network is a binary number value representation mode.
And in an intelligent control-based photovoltaic grid-connected inverter according to any of the embodiments of the present invention:
when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than a set voltage threshold, starting an alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device when the next moment comes, so as to obtain and output the alternating current equal to the standard alternating current voltage, wherein the step-up processing comprises the following steps of: the standard alternating voltage is 220 volts;
when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than the set voltage threshold, starting the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device when the next moment comes, so as to obtain and output the alternating current equal to the standard alternating current voltage, and further comprising: the value of the set voltage threshold is 36V;
when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than the set voltage threshold, starting the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device when the next moment comes, so as to obtain and output the alternating current equal to the standard alternating current voltage, and further comprising: when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is 36 volts, starting an alternating current transformer with the turns ratio of the main coil to the secondary coil being smaller than 9 to 55 when the next moment comes so as to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device to obtain and output alternating current equal to the standard alternating current voltage;
by way of example, the value of the voltage threshold is set to 36 volts, the standard alternating-current voltage is set to 220 volts, when the direct-current voltage received by the photovoltaic grid-connected inverter is smaller than 36 volts, under the condition that the conversion efficiency of power of a power grid is ensured, the alternating-current voltage after the inversion of the photovoltaic grid-connected inverter is smaller than 36 volts, an alternating-current transformer is required to be introduced, and at the moment, the alternating-current transformer with the turn ratio of the main coil and the secondary coil being enabled smaller than 9 to 55 is selected to be arranged between the photovoltaic grid-connected inverter and the power grid, so that the power supply operation of the standard alternating-current voltage is completed while the conversion efficiency of the power supply power is ensured.
Example 6
Fig. 7 is a schematic structural diagram of a photovoltaic grid-connected system according to embodiment 6 of the present invention.
As shown in fig. 7, the photovoltaic grid-connected system according to embodiment 6 of the present invention includes a junction box, a plurality of photovoltaic panels, and an intelligent control-based photovoltaic grid-connected inverter according to any of the embodiments of the present invention.
Illustratively, in fig. 7, the photovoltaic grid-tie system shown in embodiment 6 of the present invention includes a combiner box, N photovoltaic panels, and an intelligent control-based photovoltaic grid-tie inverter according to any of the embodiments of the present invention;
the N photovoltaic electric plates are in the same region and have the same maximum output power, and N is a natural number greater than or equal to 2.
In addition, the present invention may also cite the following technical matters to highlight the significant technical progress of the present invention:
in the invention, the method for sending the cyclic neural network after the completion of the multiple times of training of the preset training total number to the prediction processing equipment comprises the following steps: the value of the preset training total number and the average sunlight time of the current season of the same area where the plurality of photovoltaic electric plates are located form a monotonic forward association relation;
in the invention, the monotonic forward association between the value of the preset training total number and the average sunlight time of the current season in the same region where the plurality of photovoltaic electric plates are located comprises the following steps: expressing a monotonic forward association relationship between the value of the preset training total number and the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located by adopting a nonlinear numerical function;
the method for expressing the monotonic forward association relationship between the value of the preset training total number and the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located by adopting a nonlinear numerical function comprises the following steps: the longer the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the smaller the value of the preset training total number is.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) comprising instructions for causing a terminal (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to perform the method according to the embodiments of the present invention.
The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the claims, which are to be protected by the present invention.
Claims (10)
1. An intelligent control-based photovoltaic grid-connected inverter, characterized in that the inverter comprises:
the photovoltaic grid-connected inverter device is connected with the junction box and converts direct current from the junction box into alternating current, the junction box is connected with the photovoltaic electric plates, the photovoltaic electric plates are located in the same area, and the maximum output power of the photovoltaic electric plates is the same;
the boost control device is connected with the photovoltaic grid-connected inverter device and is used for starting the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than a set voltage threshold value, so as to obtain and output alternating current equal to the standard alternating current voltage, and connecting the alternating current output by the alternating current transformer into a power supply grid;
the prediction processing device is used for intelligently predicting the direct current voltage of the direct current of the combiner box corresponding to the next moment based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the combiner box corresponding to the plurality of moments before the next moment, wherein the plurality of moments before the next moment are equal to each other in a two-to-two interval on a time axis and form a complete duration;
the customized training device is connected with the prediction processing device and is used for sending the cyclic neural network after the repeated training of the preset training total number to the prediction processing device for use;
wherein the intelligent prediction is performed using a recurrent neural network.
2. The intelligent control-based photovoltaic grid-connected inverter of claim 1, wherein:
the boost control device is further used for disabling the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device to obtain and output alternating current equal to the standard alternating current voltage when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is equal to or higher than a set voltage threshold value and directly connecting the alternating current output by the photovoltaic grid-connected inverter device into a power supply grid;
the intelligent prediction of the direct current voltage of the direct current of the combiner box corresponding to the next moment based on the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the combiner box corresponding to the plurality of moments before the next moment comprises: the number of times before the next time is selected is proportional to the number of photovoltaic panels connected to the combiner box.
3. The intelligent control-based photovoltaic grid-tie inverter of claim 2, wherein the inverter further comprises:
the information storage device is connected with the customized training device and used for storing various network parameters of the cyclic neural network after the repeated training of the preset training total number.
4. The intelligent control-based photovoltaic grid-tie inverter of claim 2, wherein the inverter further comprises:
an ac transformer array comprising a plurality of ac transformers, each ac transformer having a primary coil and a secondary coil of different turns ratio;
the alternating current transformer array is connected with the boosting control equipment and used for providing an activated alternating current transformer for the boosting control equipment.
5. The intelligent control-based photovoltaic grid-tie inverter of claim 2, wherein the inverter further comprises:
and the content display device is connected with the boost control equipment and used for displaying the type information of the alternating-current transformer started by the boost control equipment in real time.
6. The intelligent control-based photovoltaic grid-tie inverter of claim 2, wherein the inverter further comprises:
the alternating current control cabinet is used for accommodating the photovoltaic grid-connected inversion equipment, the boosting control equipment, the prediction processing equipment and the customized training equipment;
the photovoltaic grid-connected inverter device comprises a photovoltaic grid-connected inverter device, a boost control device, a prediction processing device and a custom training device, wherein a power supply is arranged in the alternating current control cabinet and used for respectively providing power supply operation for the photovoltaic grid-connected inverter device, the boost control device, the prediction processing device and the custom training device.
7. The intelligent control-based photovoltaic grid-connected inverter of any of claims 2-6, wherein:
performing the intelligent prediction using a recurrent neural network includes: taking the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and a plurality of direct current voltages of direct current of the combiner boxes corresponding to a plurality of moments before the next moment as each input data of the circulating neural network, and operating the circulating neural network to obtain the direct current voltage of the direct current of the combiner boxes corresponding to the next moment output by the circulating neural network.
8. The intelligent control-based photovoltaic grid-connected inverter of claim 7, wherein:
taking the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and a plurality of direct current voltages of direct current of the combiner boxes respectively corresponding to a plurality of moments before the next moment as each input data of the circulating neural network, and operating the circulating neural network to obtain the direct current voltage of the direct current of the combiner boxes corresponding to the next moment output by the circulating neural network, wherein the steps of: before the average sunlight duration of the current season in the same region where the plurality of photovoltaic panels are located, the maximum output power and a plurality of direct current voltages of direct current of the combiner boxes respectively corresponding to a plurality of moments before the next moment are input as respective input data to the cyclic neural network, respectively performing binary value conversion on the average sunlight duration of the current season in the same region where the plurality of photovoltaic panels are located, the maximum output power and the plurality of direct current voltages of direct current of the combiner boxes respectively corresponding to a plurality of moments before the next moment;
the method for obtaining the direct current voltage of the junction box corresponding to the next moment output by the circulating neural network further comprises the steps of taking the average sunlight duration of the current season of the same region where the plurality of photovoltaic electric plates are located, the maximum output power and the plurality of direct current voltages of the direct current of the junction box corresponding to the plurality of moments before the next moment as the input data of the circulating neural network, and operating the circulating neural network to obtain the direct current voltage of the direct current of the junction box corresponding to the next moment output by the circulating neural network: and the obtained direct current voltage of the direct current of the combiner box corresponding to the next moment output by the cyclic neural network is a binary number value representation mode.
9. The intelligent control-based photovoltaic grid-connected inverter of any of claims 2-6, wherein:
when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than a set voltage threshold, starting an alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device when the next moment comes, so as to obtain and output the alternating current equal to the standard alternating current voltage, wherein the step-up processing comprises the following steps of: the standard alternating voltage is 220 volts;
when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than the set voltage threshold, starting the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device when the next moment comes, so as to obtain and output the alternating current equal to the standard alternating current voltage, and further comprising: the value of the set voltage threshold is 36V;
when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is lower than the set voltage threshold, starting the alternating current transformer to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device when the next moment comes, so as to obtain and output the alternating current equal to the standard alternating current voltage, and further comprising: when the predicted direct current voltage of the direct current of the combiner box corresponding to the next moment is 36V, an alternating current transformer with the turns ratio of the main coil to the secondary coil being smaller than 9 to 55 is started when the next moment comes so as to boost the alternating current voltage of the alternating current output by the photovoltaic grid-connected inverter device to obtain and output the alternating current equal to the standard alternating current voltage.
10. A photovoltaic grid-tie system comprising a combiner box, a plurality of photovoltaic panels, and an intelligent control-based photovoltaic grid-tie inverter as claimed in any one of claims 1-9.
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