CN111049188A - Multi-input photovoltaic inverter system centralized mode MPPT method and application device thereof - Google Patents
Multi-input photovoltaic inverter system centralized mode MPPT method and application device thereof Download PDFInfo
- Publication number
- CN111049188A CN111049188A CN202010001467.3A CN202010001467A CN111049188A CN 111049188 A CN111049188 A CN 111049188A CN 202010001467 A CN202010001467 A CN 202010001467A CN 111049188 A CN111049188 A CN 111049188A
- Authority
- CN
- China
- Prior art keywords
- input
- photovoltaic
- inverter
- inverter system
- input module
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 60
- 238000005070 sampling Methods 0.000 claims description 57
- HEZMWWAKWCSUCB-PHDIDXHHSA-N (3R,4R)-3,4-dihydroxycyclohexa-1,5-diene-1-carboxylic acid Chemical compound O[C@@H]1C=CC(C(O)=O)=C[C@H]1O HEZMWWAKWCSUCB-PHDIDXHHSA-N 0.000 claims description 30
- 238000010248 power generation Methods 0.000 abstract description 4
- 238000006243 chemical reaction Methods 0.000 description 25
- 239000003990 capacitor Substances 0.000 description 5
- 230000009194 climbing Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004422 calculation algorithm Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Landscapes
- Inverter Devices (AREA)
Abstract
The invention relates to the technical field of photovoltaic power generation, in particular to a centralized mode MPPT method of a multi-input photovoltaic inverter system and an application device thereof. In the method, when the multi-input photovoltaic inverter system operates in a centralized mode, the following steps are executed in groups for photovoltaic input modules which are directly input to an inverter circuit in the multi-input photovoltaic inverter system according to a preset sequence: in a corresponding preset time period, the inverter circuit in the multi-input photovoltaic inverter system is controlled to adjust the direct-current bus voltage in the multi-input photovoltaic inverter system, and the maximum power point corresponding to the photovoltaic input module is searched, so that the purpose of tracking and identifying the maximum power point of each path of photovoltaic input module directly input to the inverter circuit is achieved.
Description
Technical Field
The invention relates to the technical field of photovoltaic power generation, in particular to a centralized mode MPPT method of a multi-input photovoltaic inverter system and an application device thereof.
Background
The topological relation of most medium and small power photovoltaic inverters is shown in fig. 1, a plurality of photovoltaic input modules are connected with a direct current bus through corresponding DCDC conversion circuits, and the direct current bus is inverted and output-controlled through one inverter circuit (such as the DCAC conversion circuit shown in fig. 1).
When the direct current bus voltage meets the inversion requirement, several or all of the DCDC conversion circuits with the maximum power points close to each other can be controlled to stop working, so that the corresponding photovoltaic input modules are directly input to the inverter circuit, the loss of current flowing through the DCDC conversion circuits is reduced, the overall conversion efficiency of the photovoltaic inverter can be improved, and the working condition is generally defined as a concentrated mode of the photovoltaic inverter.
However, since the DCDC conversion circuit stops working at this time, the photovoltaic inverter cannot directly track and identify the maximum power point of the corresponding path of photovoltaic input module.
Disclosure of Invention
In view of this, the present invention provides a concentrated mode MPPT method for a multi-input photovoltaic inverter system and an application apparatus thereof, so as to track and identify a maximum power point of each path of photovoltaic input module directly input to an inverter circuit.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
the application provides in a first aspect a multi-input photovoltaic inverter system centralized mode MPPT method, which is applied to a controller in a multi-input photovoltaic inverter system, the multi-input photovoltaic inverter system centralized mode MPPT method including:
when the multi-input photovoltaic inverter system operates in a centralized mode, according to a preset sequence, grouping and executing the following steps on photovoltaic input modules which are directly input to an inverter circuit in the multi-input photovoltaic inverter system:
and in a corresponding preset time period, the inverter circuit is controlled to adjust the direct-current bus voltage of the multi-input photovoltaic inverter system, and the maximum power point corresponding to the photovoltaic input module is searched.
Optionally, in each preset time period, a group of photovoltaic input modules with the maximum power point is searched, and the group of photovoltaic input modules is a path of photovoltaic input module;
through control inverter circuit adjusts the direct current busbar voltage of many input photovoltaic inverter system, seeks the maximum power point that corresponds photovoltaic input module, includes:
calculating the power value of the corresponding photovoltaic input module according to the acquired sampling information of the corresponding photovoltaic input module; and changing the voltage value of the direct current bus voltage in the direction of increasing the power value of the corresponding photovoltaic input module by taking the current voltage value of the direct current bus voltage as a starting point until the power value of the corresponding photovoltaic input module reaches the maximum value.
Optionally, in each preset time period, searching for a group of photovoltaic input modules with a maximum power point, including multiple paths of photovoltaic input modules;
through control inverter circuit adjusts the direct current busbar voltage of many input photovoltaic inverter system, seeks the maximum power point that corresponds photovoltaic input module, includes:
adjusting the voltage value of the direct current bus voltage according to a preset rule; calculating power values of the corresponding photovoltaic input modules under different direct-current bus voltages according to the acquired sampling information of the corresponding photovoltaic input modules;
and taking the maximum value of all power values of the corresponding photovoltaic input module as the maximum power point of the corresponding photovoltaic input module under different direct-current bus voltages.
Optionally, in a preset time period, the group of photovoltaic input modules for finding the maximum power point includes all photovoltaic input modules directly input to the inverter circuit.
Optionally, when the power value of the corresponding photovoltaic input module is calculated, the method further includes:
if sampling information does not exist in the photovoltaic input module directly input to the inverter circuit in one path, calculating the power value of the photovoltaic input module in the path according to the current alternating current side power of the inverter circuit and the power values of the photovoltaic input modules in the other paths.
Optionally, the sampling information corresponding to the photovoltaic input module includes: the direct current bus voltage and the current sampling value corresponding to the photovoltaic input module, or the current sampling value and the voltage sampling value corresponding to the photovoltaic input module.
Optionally, the intervals between the preset time periods are the same or partially the same, or all are different.
Optionally, the method further includes: when the multi-input photovoltaic inverter system operates in a centralized mode, the following steps are executed firstly:
and controlling the inverter circuit to adjust the voltage of the direct current bus so as to maximize the direct current side power or the alternating current side power of the inverter circuit.
Optionally, after obtaining a maximum power point of all photovoltaic input modules directly input to the inverter circuit, the method further includes:
and returning to control the inverter circuit to adjust the voltage of the direct current bus so as to maximize the direct current side power or the alternating current side power of the inverter circuit.
The present application provides in a second aspect a multiple-input photovoltaic inverter system comprising: a centralized inverter and a plurality of first sampling circuits; wherein:
the direct current side of the centralized inverter is used as the input end of the multi-input photovoltaic inverter system and is respectively connected to a plurality of photovoltaic input modules;
the alternating current side of the centralized inverter is used as the output end of the multi-input photovoltaic inverter system and is used for being connected with a power grid;
each path of photovoltaic input module is respectively provided with a first sampling circuit, and the output end of each first sampling circuit is connected with a controller in the centralized inverter;
the controller in the centralized inverter is configured to perform the MPPT method for the concentrated mode of the multi-input photovoltaic inverter system according to any one of the first aspect of the present application.
A third aspect of the present application provides a multiple-input photovoltaic inverter system, comprising: the system comprises a first controller, a centralized inverter and a plurality of DCDC converters; wherein:
the input end of each DCDC converter is respectively used as each input end of the multi-input photovoltaic inverter system and is connected to a corresponding photovoltaic input module;
the output end of each DCDC converter is connected with the direct current side of the centralized inverter;
the alternating current side of the centralized inverter is used as the output end of the multi-input photovoltaic inverter system and is used for being connected with a power grid;
the control end of each DCDC converter is connected with the first controller;
the first controller is configured to execute the MPPT method for the concentrated mode of the multi-input photovoltaic inverter system according to any one of the first aspect of the present application.
Optionally, the first controller is a controller in the centralized inverter; alternatively, the first and second electrodes may be,
the first controller is a system controller, and a controller in the centralized inverter is connected with the system controller.
The present application provides in a fourth aspect a multiple-input photovoltaic inverter system comprising: the controller of the medium-low power inverter is used for executing the MPPT method of the multi-input photovoltaic inverter system in the centralized mode.
According to the technical scheme, when the multi-input photovoltaic inverter system operates in the centralized mode, the MPPT method for the centralized mode of the multi-input photovoltaic inverter system provided by the invention performs the following steps in groups for the photovoltaic input modules which are directly input into the inverter circuit in the multi-input photovoltaic inverter system according to the preset sequence: in a corresponding preset time period, the inverter circuit in the multi-input photovoltaic inverter system is controlled to adjust the direct-current bus voltage in the multi-input photovoltaic inverter system, and the maximum power point corresponding to the photovoltaic input module is searched, so that the purpose of tracking and identifying the maximum power point of each path of photovoltaic input module directly input to the inverter circuit is achieved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic diagram of a structure of a low-medium power multi-input photovoltaic inverter in the prior art;
fig. 2 is a schematic flowchart of a concentrated mode MPPT method of a multi-input photovoltaic inverter system according to an embodiment of the present disclosure;
fig. 3 is a schematic flowchart of another specific implementation of step S100 according to an embodiment of the present disclosure;
fig. 4 is a schematic flowchart of another implementation of a concentrated mode MPPT method for a multi-input photovoltaic inverter system according to an embodiment of the present disclosure;
fig. 5 to 7 are schematic structural diagrams of three multi-input photovoltaic inverter systems provided in the embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In this application, 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 an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
In the prior art, in a low-power photovoltaic inverter as shown in fig. 1, each path of photovoltaic input module is connected to a dc bus through a corresponding DCDC conversion circuit, and the dc generated by the photovoltaic input module is subjected to step-down/step-up conversion by the DCDC conversion circuit, so that the dc bus voltage meets the dc side voltage requirement of the inverter circuit; the dc bus is also connected to an inverter circuit (DCAC conversion circuit in fig. 1) through which ac power is output, and a dc bus capacitor is connected in parallel between the positive and negative electrodes of the dc bus to prevent fluctuations in the dc bus voltage.
However, since the DCDC conversion circuit is added between each path of the photovoltaic input module and the dc bus, when the DCDC conversion circuit works, a loss is inevitably generated on the current flowing through the DCDC conversion circuit, so that the overall conversion efficiency of the multi-input photovoltaic inverter system is reduced, and energy loss is caused. Therefore, on the premise that the direct-current bus voltage meets the direct-current side voltage requirement of the inverter circuit, the DCDC conversion circuits respectively connected with the photovoltaic input modules with the same or similar maximum power points are controlled to stop working, so that the photovoltaic input modules are directly input into the inverter circuit, and the overall conversion efficiency of the photovoltaic inverter is improved.
However, since the several lines of photovoltaic input modules are directly input to the inverter circuit, if the several lines of photovoltaic input modules are respectively tracked and identified by the maximum power point, only the several lines of photovoltaic input modules are put into the normal operation mode again, that is, the DCDC conversion circuits respectively connected to the several lines of photovoltaic input modules start to operate again.
In order to solve the problem, an embodiment of the present application provides a concentrated mode MPPT method for a multi-input photovoltaic inverter system, which is applied to a controller in the multi-input photovoltaic inverter system, and a specific flow of the method is shown in fig. 2, where the method specifically includes the following steps executed when the multi-input photovoltaic inverter system operates in a concentrated mode:
and S10, grouping the photovoltaic input modules which are directly input to the inverter circuit in the multi-input photovoltaic inverter system according to a preset sequence, and executing the step S100.
In practical application, the grouping mode of each path of photovoltaic input module directly input to the inverter circuit is specifically as follows:
the inverter circuit is divided into at least one group, each group comprises at least one path of each path of photovoltaic input module which is directly input to the inverter circuit, of course, each group can comprise a certain path of corresponding photovoltaic input module which is directly input to the inverter circuit, however, each path of photovoltaic input module which is directly input to the inverter circuit is ensured to appear in each group at least once, and preferably, each path of photovoltaic input module which is directly input to the inverter circuit appears in each group only once.
Specifically, for example, it is assumed that the multi-input photovoltaic inverter system is connected to 5-way photovoltaic input modules, which are respectively denoted as: the photovoltaic input module comprises a first path of photovoltaic input module, a second path of photovoltaic input module, a third path of photovoltaic input module, a fourth path of photovoltaic input module and a fifth path of photovoltaic input module; the photovoltaic input module which is directly input to the inverter circuit has 5 paths in total; and, assume that there are three groups in total, which are respectively noted as: a first group, a second group, and a third group; wherein the first group may include: the system comprises a first path of photovoltaic input module and a third path of photovoltaic input module; the second group may include: a second group of photovoltaic input modules and a fourth path of photovoltaic input modules; the third group may include: the photovoltaic input module comprises a third path of photovoltaic input module, a fourth path of photovoltaic input module and a fifth path of photovoltaic input module.
The preferred grouping method is as follows: each group comprises one of the photovoltaic input modules, and each photovoltaic input module which is directly input into the inverter circuit is ensured to appear in each group at least once. For example, if the number of the photovoltaic input modules directly input to the inverter circuit is 5, the photovoltaic input modules are divided into five groups, the first group includes a first photovoltaic input module, the second group includes a second photovoltaic input module, the third group includes a third photovoltaic input module, the fourth group includes a fourth photovoltaic input module, and the fifth group includes a fifth photovoltaic input module. For better explanation, the following explanation is made in detail by taking this as an example.
In practical applications, the preset sequence is a sequence preset according to practical situations, for example, if the preset sequence is divided into five groups, the sequence is according to the first group, the second group, the third group, the fourth group and the fifth group, and other sequences may also be adopted in practical applications, which is not specifically limited herein, and a suitable execution sequence may be selected according to situations.
Wherein, step S100 specifically is: and in a corresponding preset time period, the inverter circuit in the multi-input photovoltaic inverter system is controlled to adjust the direct-current bus voltage of the multi-input photovoltaic inverter system, and the maximum power point corresponding to the photovoltaic input module is searched.
The preset time period is a period of time with a time length preset according to actual conditions, such as T1 to T2, and can be adjusted according to use requirements when in actual use.
In addition, it should be further noted that the intervals between the preset time periods may be the same, for example, the first preset time period is: t1 to T2, a second preset time period T2+ Δ T to T3, a third preset time period T3+ Δ T to T4, a fourth preset time period T4+ Δ T to T5, a fifth preset time period T5+ Δ T to T6; the same may be true, for example, the first preset time period is: t1 to T2, a second preset time period T2+ Δ T1 to T3, a third preset time period T3+ Δ T1 to T4, a fourth preset time period T4+ Δ T2 to T5, a fifth preset time period T5+ Δ T2 to T6; it may also be different, for example, the first preset time period is: t1 to T2, a second preset time period T2+ Δ T1 to T3, a third preset time period T3+ Δ T2 to T4, a fourth preset time period T4+ Δ T3 to T5, a fifth preset time period T5+ Δ T1 to T6; the method is not limited herein, and can be selected according to specific situations, and is within the scope of the present application.
In practical application, if a group of photovoltaic input modules for finding the maximum power point is a single-path photovoltaic input module in each preset time period, in step S100, the inverter circuit in the multi-input photovoltaic inverter system is controlled to adjust the dc bus voltage of the multi-input photovoltaic inverter system, and the specific implementation manner for finding the maximum power point corresponding to the photovoltaic input module is as follows:
calculating the power value of the corresponding photovoltaic input module according to the acquired sampling information of the corresponding photovoltaic input module; and changing the voltage value of the direct current bus voltage in the direction of increasing the power value of the corresponding photovoltaic input module by taking the current voltage value of the direct current bus voltage as a starting point until the power value of the corresponding photovoltaic input module reaches the maximum value.
Wherein, the sampling information of corresponding photovoltaic input module includes: the method comprises the steps of obtaining a direct current bus voltage and a current sampling value corresponding to a photovoltaic input module, or obtaining a current sampling value and a voltage sampling value corresponding to the photovoltaic input module. Specifically, a controller in the multi-input photovoltaic inverter system at least needs to acquire a current sampling value corresponding to a photovoltaic input module under each direct-current bus voltage; when the sampling information corresponding to the photovoltaic input module comprises a current sampling value and a direct-current bus voltage, a controller in the multi-input photovoltaic inverter system multiplies the current sampling value of the corresponding photovoltaic input module under each direct-current bus voltage by the corresponding direct-current bus voltage, and then the power value of the corresponding photovoltaic input module can be calculated; when the sampling information corresponding to the photovoltaic input module comprises a current sampling value and a voltage sampling value of the photovoltaic input module, the controller in the multi-input photovoltaic inverter system multiplies the current sampling value and the voltage sampling value of the corresponding photovoltaic input module under each direct-current bus voltage, and the power value of the corresponding photovoltaic input module can also be calculated; the two sampling methods may be determined according to specific situations, and are not specifically limited herein, and are within the scope of the present application.
Taking the first group including the first path of photovoltaic input module as an example, firstly, according to the collected current sampling value (for example, 10A) of the first path of photovoltaic input module and the current voltage value (for example, 500V) of the dc bus voltage, calculating the power value (namely, 5000W) of the first path of photovoltaic input module at the time; then, taking the current voltage value (namely 500V) of the direct current bus voltage as a starting point, adjusting the direct current bus voltage to the left and the right of the current voltage value (namely 500V) by one step (the step length can be determined according to specific conditions), and obtaining the direction in which the power value of the first path of photovoltaic module is increased, wherein the direction is assumed to be the direction in which the direct current bus voltage is increased; adjusting the voltage of the direct current bus according to the increasing direction, and calculating the power value of the first path of photovoltaic input module at the moment according to the collected current sampling value of the first path of photovoltaic input module and the voltage value of the direct current bus voltage at the moment; and repeating the steps until the maximum value of the power value of the first path of photovoltaic input module is found.
It should be noted that the above is only an example, and other methods for finding the maximum power point in the prior art may be applicable, such as a hill climbing method or a three-point method, which is not described herein again.
In addition, in practical application, if a group of the photovoltaic input modules which search for the maximum power point in each preset time period is a multi-path photovoltaic input module, in step S100, the inverter circuit in the multi-input photovoltaic inverter system is controlled to adjust the dc bus voltage of the multi-input photovoltaic inverter system, and another specific embodiment of searching for the maximum power point corresponding to the photovoltaic input module is shown in fig. 3, and specifically includes:
s110, adjusting the voltage value of the direct current bus voltage according to a preset rule, and calculating power values of the corresponding photovoltaic input modules under different direct current bus voltages according to the collected sampling information of the corresponding photovoltaic input modules.
It should be noted that, adjusting the voltage value of the dc bus voltage and calculating the power value of the corresponding photovoltaic input module under different dc bus voltages are performed synchronously; in addition, the calculation manner of calculating the power values of the corresponding photovoltaic input modules at different dc bus voltages according to the collected sampling information of the corresponding photovoltaic input modules in step S110 is the same as that in the previous embodiment, and is not repeated here.
In practical application, the preset rule may be: the step-up of the voltage value of the regulated dc bus voltage from the minimum value to the maximum value may also be: the step of adjusting the voltage value of the dc bus voltage to decrease from the maximum value to the minimum value may further be: adjusting the voltage value of the direct current bus voltage to gradually increase or decrease from the current voltage value until the maximum power point of all the photovoltaic input modules in the group is found, or the gradual conversion times reach the preset times; at the moment, the voltage value of the voltage of the direct current bus is adjusted to move in the opposite direction from the original voltage value until the maximum power point of all the photovoltaic input modules in the group is found; the three adjustment manners may be determined according to specific situations, and are not specifically limited herein, and are all within the protection scope of the present application.
And S120, taking the maximum value of all power values of the corresponding photovoltaic input module as the maximum power point of the corresponding photovoltaic input module under different direct-current bus voltages.
It should be noted that the maximum value of the power values corresponding to the photovoltaic input module is the power value at the vertex of the power value change of the corresponding photovoltaic input module under different direct-current bus voltages; specifically, a hill climbing method or a three-point method may be adopted to find the maximum power point corresponding to the photovoltaic input module, which is not described herein any more.
In the two embodiments, when the power value corresponding to the photovoltaic input module is calculated, if there is no sampling information, i.e., a sampling current value, in a photovoltaic input module directly input to the inverter circuit, the power value of the photovoltaic input module in a certain path is calculated according to the ac-side power of the current inverter circuit and the power values of other paths of photovoltaic input modules.
Specifically, the current power of the alternating current side of the inverter circuit can be calculated and recorded as Pinv according to the current sampling value and the voltage sampling value of the alternating current side of the inverter circuit; if the multi-input photovoltaic inverter system is connected with the N paths of photovoltaic input modules, and the current power of each path of photovoltaic input module is respectively recorded as Pv1 and Pv2 … PvN, wherein a current sampling value does not exist in a certain path of photovoltaic input module, the current power Pvx of the path of photovoltaic input module is Pinv-P v1-Pv2- … -PvN.
In a limit, in a preset time period, the group of photovoltaic input modules for searching the maximum power point may include all photovoltaic input modules directly input to the inverter circuit, that is, in a preset time period, the inverter circuit in the multi-input photovoltaic inverter system is controlled to adjust the dc bus voltage of the multi-input photovoltaic inverter system, and the maximum power point of all photovoltaic input modules directly input to the inverter circuit is searched.
It should be noted that the two specific embodiments of step S100 may be selected according to circumstances, and are not specifically limited herein and are within the scope of the present application; however, the second embodiment has a large adjustment range of the dc bus voltage and therefore has an influence on the amount of power generation of the multi-input photovoltaic inverter system, whereas the first embodiment has a small adjustment range of the dc bus voltage and therefore has a small influence on the amount of power generation of the multi-input photovoltaic inverter system, and therefore the first embodiment is preferable.
In summary, according to the MPPT method for the centralized mode of the multi-input photovoltaic inverter system provided by the present invention, when the multi-input photovoltaic inverter system operates in the centralized mode, the inverter circuit is controlled to adjust the dc bus voltage of the multi-input photovoltaic inverter system in the corresponding preset time period according to the preset sequence, and the maximum power point of the corresponding photovoltaic input module is searched in groups for the photovoltaic input modules directly input to the inverter circuit in the multi-input photovoltaic inverter system, so as to realize the purpose of tracking and identifying the maximum power point of each path of the photovoltaic input modules directly input to the inverter circuit.
Another embodiment of the present application provides another implementation of the MPPT method in the centralized mode for the multi-input photovoltaic inverter system, and the specific flow is shown in fig. 4, on the basis of the foregoing embodiment, before step S10, the method further includes, when the multi-input photovoltaic inverter system operates in the centralized mode, first performing the following steps:
s200, controlling an inverter circuit in the multi-input photovoltaic inverter system to adjust the voltage of a direct current bus, and enabling the direct current side power or alternating current side power of the inverter circuit to be maximum.
It should be noted that, the tracking and identifying process of the dc-side power or the ac-side power of the inverter circuit is similar to the above embodiment, and can be obtained by performing analog derivation with reference to the above embodiment, and details are not repeated here.
It should be noted that, at this time, after the maximum power points of all the photovoltaic input modules directly input to the inverter circuit are obtained, that is, after step S100 is executed for all the groups of photovoltaic input modules directly input to the inverter circuit, step S200 is executed again.
The rest steps are the same as the above embodiments, and are not described in detail here.
Another embodiment of the present application provides a multi-input photovoltaic inverter system, the specific structure of which is shown in fig. 5, including: a centralized inverter 10 and a plurality of first sampling circuits 20.
The direct current side of the centralized inverter 10 is used as the input end of the multi-input photovoltaic inverter system and is respectively connected to the multi-path photovoltaic input modules; the ac side of the centralized inverter 10 is used as the output of the multi-input photovoltaic inverter system for connection to the grid.
Each path of photovoltaic input module is respectively configured with one first sampling circuit 20, and the output end of each first sampling circuit 20 is connected to the controller in the centralized inverter 10.
The centralized inverter 10 includes an inverter circuit and a controller, wherein an input end of the controller is connected to an output end of each first sampling circuit 20, and is configured to execute the MPPT method in the centralized mode of the multi-input photovoltaic inverter system provided in any of the above embodiments, which is not described herein again.
Although each path of the photovoltaic input module of the multi-input photovoltaic inverter system provided in this embodiment is not equipped with a corresponding DCDC conversion circuit, due to the existence of each first sampling circuit 20, the multi-input photovoltaic inverter system centralized-mode MPPT method provided in any of the above embodiments can be implemented as well.
It should be noted that the first sampling circuit 20 may be only used for sampling the current flowing through itself, or may sample both the current flowing through itself and the voltage across itself, and this is not specifically limited herein, and may be determined according to specific situations, and all of them are within the protection scope of the present application.
The embodiment further provides another multi-input photovoltaic inverter system, the specific structure of which is shown in fig. 6, including: a first controller 40, a centralized inverter 10, and a plurality of DCDC converters 30.
The input end of each DCDC converter 30 is respectively used as each input end of the multi-input photovoltaic inverter system and is connected to a corresponding photovoltaic input module; the output end of each DCDC converter 30 is connected to the dc side of the centralized inverter 10; the ac side of the centralized inverter 10 is used as the output of the multi-input photovoltaic inverter system for connection to the grid.
The control terminal of each DCDC converter 30 is connected to the first controller 40; the first controller 40 is configured to execute the MPPT method of the multi-input photovoltaic inverter system in the centralized mode provided in any of the above embodiments.
Note that, the first controller 40 is a controller in the centralized inverter 10; alternatively, the first controller 40 is a system controller (as shown in fig. 6) and is connected to the controller 11 in the centralized inverter 10.
The present embodiment further provides an implementation of a centralized inverter, and a specific structure of the implementation is as shown in fig. 5 or fig. 6, where the implementation includes: controller 11, first inverter circuit 12 and first dc bus capacitance C1.
The dc side of first inverter circuit 12 is the dc side of the centralized inverter and the ac side of first inverter circuit 12 is the ac side of the centralized inverter.
The first dc bus capacitor C1 is connected between the positive electrode and the negative electrode on the dc side of the first inverter circuit 12; an output end of the controller 11 is connected with a control end of the first inverter circuit 12.
Another embodiment of the present application provides a multi-input photovoltaic inverter system, which is suitable for a scene with a large output power, and a specific structure of the multi-input photovoltaic inverter system is shown in fig. 7, including: the medium and small power inverter 50, wherein the controller of the medium and small power inverter 50 is used in the multi-input photovoltaic inverter system centralized mode MPPT method provided in any of the above embodiments.
The present embodiment further provides an implementation of the medium-low power inverter 50, and the specific structure thereof is shown in fig. 7, and includes: the second sampling circuit 54 is connected to the second controller 51, the second inverter circuit 52, the second dc bus capacitor C2, the at least one DCDC conversion circuit 53, and the second dc bus capacitor C2.
Each output terminal of the second controller 51 and the control terminal of the corresponding DCDC conversion circuit 53; respective input terminals of the second controller 51 are connected to output terminals of the corresponding second sampling circuits 54; the second controller 51 is configured to execute the MPPT method of the concentrated mode of the multi-input photovoltaic inverter system provided in any one of the above embodiments.
The first side of each DCDC conversion circuit 53 is connected to a corresponding photovoltaic input module; the second side of each DCDC conversion circuit 53 is connected to a dc bus.
Each second sampling circuit 54 may be disposed between the first side of the corresponding DCDC conversion circuit 53 and the corresponding photovoltaic input module (not shown), may also be disposed between the second side of the corresponding DCDC conversion circuit 53 and the dc bus (as shown in fig. 7), and may even be disposed at two positions, which are not specifically limited herein and may be selected as appropriate, and all of them are within the protection scope of the present application.
The direct current bus is also connected with the direct current side of a second inverter circuit 52, and the alternating current side of the second inverter circuit 52 is used as the alternating current side of the medium-low power inverter 50 through a second sampling circuit 54; the second dc bus capacitor C2 is connected between the positive and negative poles of the dc bus.
It should be noted that the second sampling circuit 54 may be used only for sampling the current flowing through itself, or may sample both the current flowing through itself and the voltage across itself, and is not specifically limited herein, and may be determined according to specific situations, and all of them are within the protection scope of the present application.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are merely illustrative, wherein units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (13)
1. The MPPT method for the centralized mode of the multi-input photovoltaic inverter system is applied to a controller in the multi-input photovoltaic inverter system, and comprises the following steps:
when the multi-input photovoltaic inverter system operates in a centralized mode, according to a preset sequence, grouping and executing the following steps on photovoltaic input modules which are directly input to an inverter circuit in the multi-input photovoltaic inverter system:
and in a corresponding preset time period, the inverter circuit is controlled to adjust the direct-current bus voltage of the multi-input photovoltaic inverter system, and the maximum power point corresponding to the photovoltaic input module is searched.
2. The MPPT method according to claim 1, wherein a group of the pv input modules for finding a maximum power point in each preset time period is a single path of the pv input modules;
through control inverter circuit adjusts the direct current busbar voltage of many input photovoltaic inverter system, seeks the maximum power point that corresponds photovoltaic input module, includes:
calculating the power value of the corresponding photovoltaic input module according to the acquired sampling information of the corresponding photovoltaic input module; and changing the voltage value of the direct current bus voltage in the direction of increasing the power value of the corresponding photovoltaic input module by taking the current voltage value of the direct current bus voltage as a starting point until the power value of the corresponding photovoltaic input module reaches the maximum value.
3. The MPPT method of claim 1, wherein the set of pv input modules for finding the maximum power point in each predetermined time period includes multiple pv input modules;
through control inverter circuit adjusts the direct current busbar voltage of many input photovoltaic inverter system, seeks the maximum power point that corresponds photovoltaic input module, includes:
adjusting the voltage value of the direct current bus voltage according to a preset rule; calculating power values of the corresponding photovoltaic input modules under different direct-current bus voltages according to the acquired sampling information of the corresponding photovoltaic input modules;
and taking the maximum value of all power values of the corresponding photovoltaic input module as the maximum power point of the corresponding photovoltaic input module under different direct-current bus voltages.
4. The MPPT method for multiple-input PV inverter system in concentrated mode as claimed in claim 3, wherein the set of PV input modules seeking the maximum power point during a predetermined time period includes all PV input modules directly input to the inverter circuit.
5. The MPPT method of claim 2 or 3, wherein the method further includes, while calculating the power value of the corresponding pv input module:
if sampling information does not exist in the photovoltaic input module directly input to the inverter circuit in one path, calculating the power value of the photovoltaic input module in the path according to the current alternating current side power of the inverter circuit and the power values of the photovoltaic input modules in the other paths.
6. The MPPT method for the concentrated mode of the multi-input photovoltaic inverter system according to claim 2 or 3, wherein sampling information corresponding to the photovoltaic input module comprises: the direct current bus voltage and the current sampling value corresponding to the photovoltaic input module, or the current sampling value and the voltage sampling value corresponding to the photovoltaic input module.
7. The MPPT method for the concentrated mode of the multi-input photovoltaic inverter system as claimed in claim 2 or 3, wherein the intervals between the preset time periods are the same or partially the same or all different.
8. The multi-input photovoltaic inverter system concentrated mode MPPT method according to any one of claims 1 to 3, further comprising: when the multi-input photovoltaic inverter system operates in a centralized mode, the following steps are executed firstly:
and controlling the inverter circuit to adjust the voltage of the direct current bus so as to maximize the direct current side power or the alternating current side power of the inverter circuit.
9. The MPPT method of claim 8, wherein after obtaining a maximum power point for all photovoltaic input modules directly input to the inverter circuit, the MPPT method further comprises:
and returning to control the inverter circuit to adjust the voltage of the direct current bus so as to maximize the direct current side power or the alternating current side power of the inverter circuit.
10. A multiple-input photovoltaic inverter system, comprising: a centralized inverter and a plurality of first sampling circuits; wherein:
the direct current side of the centralized inverter is used as the input end of the multi-input photovoltaic inverter system and is respectively connected to a plurality of photovoltaic input modules;
the alternating current side of the centralized inverter is used as the output end of the multi-input photovoltaic inverter system and is used for being connected with a power grid;
each path of photovoltaic input module is respectively provided with a first sampling circuit, and the output end of each first sampling circuit is connected with a controller in the centralized inverter;
a controller in the centralized inverter for performing the multi-input photovoltaic inverter system centralized mode MPPT method of any one of claims 1-9.
11. A multiple-input photovoltaic inverter system, comprising: the system comprises a first controller, a centralized inverter and a plurality of DCDC converters; wherein:
the input end of each DCDC converter is respectively used as each input end of the multi-input photovoltaic inverter system and is connected to a corresponding photovoltaic input module;
the output end of each DCDC converter is connected with the direct current side of the centralized inverter;
the alternating current side of the centralized inverter is used as the output end of the multi-input photovoltaic inverter system and is used for being connected with a power grid;
the control end of each DCDC converter is connected with the first controller;
the first controller is configured to perform the multi-input photovoltaic inverter system concentrated mode MPPT method of any one of claims 1-9.
12. The multi-input photovoltaic inversion system of claim 11, wherein the first controller is a controller in the centralized inverter; alternatively, the first and second electrodes may be,
the first controller is a system controller, and a controller in the centralized inverter is connected with the system controller.
13. A multiple-input photovoltaic inverter system, comprising: a medium and small power inverter, the controller of which is configured to perform the multi-input photovoltaic inverter system concentrated mode MPPT method of any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010001467.3A CN111049188A (en) | 2020-01-02 | 2020-01-02 | Multi-input photovoltaic inverter system centralized mode MPPT method and application device thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010001467.3A CN111049188A (en) | 2020-01-02 | 2020-01-02 | Multi-input photovoltaic inverter system centralized mode MPPT method and application device thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111049188A true CN111049188A (en) | 2020-04-21 |
Family
ID=70243804
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010001467.3A Pending CN111049188A (en) | 2020-01-02 | 2020-01-02 | Multi-input photovoltaic inverter system centralized mode MPPT method and application device thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111049188A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009072075A2 (en) * | 2007-12-05 | 2009-06-11 | Solaredge Technologies Ltd. | Photovoltaic system power tracking method |
| CN102611341A (en) * | 2012-03-12 | 2012-07-25 | 深圳市英威腾电气股份有限公司 | Photovoltaic inverter and method for tracking maximum power of same |
| CN109888819A (en) * | 2019-01-08 | 2019-06-14 | 许继集团有限公司 | A kind of photovoltaic generating system and its control method and device |
-
2020
- 2020-01-02 CN CN202010001467.3A patent/CN111049188A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009072075A2 (en) * | 2007-12-05 | 2009-06-11 | Solaredge Technologies Ltd. | Photovoltaic system power tracking method |
| CN102611341A (en) * | 2012-03-12 | 2012-07-25 | 深圳市英威腾电气股份有限公司 | Photovoltaic inverter and method for tracking maximum power of same |
| CN109888819A (en) * | 2019-01-08 | 2019-06-14 | 许继集团有限公司 | A kind of photovoltaic generating system and its control method and device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9906189B2 (en) | Resonant switched-capacitor gyrator-type converter with local MPPT capability for PV cells | |
| Shadmand et al. | Maximum Power Point Tracking using Model Predictive Control of a flyback converter for photovoltaic applications | |
| CN111049381B (en) | Multi-target collaborative optimization control method applied to direct-current three-level converter | |
| Ramki et al. | Comparison of different DC-DC converter for MPPT application of photovoltaic system | |
| Sahu et al. | Performance analysis of multiple input converter for standalone photovoltaic system | |
| Pendem et al. | Assessment of cross-coupling effects in PV string-integrated-converters with P&O MPPT algorithm under various partial shading patterns | |
| Jiang et al. | Energy efficient fine-grained approach for solar photovoltaic management system | |
| Kiran Kumar et al. | Performance evaluation of solar PV using multiple level voltage gain boost converter with CLC cell | |
| Takahashi et al. | A multi-terminal power flow control method for next-generation DC power network | |
| Suganthi et al. | Improved three phase H-7 transformerless inverter with DPWM to reduce leakage current using CNN based deep learning technique | |
| Sangeetha et al. | Design and implementation of SEPIC converter based PV system using modified incremental conductance algorithm | |
| Basoglu et al. | Hardware based comparison of buck-boost converter topologies in MPPT systems | |
| Mounica et al. | Bipolar bidirectional DC-DC converter for bi-polar DC micro-grids with energy storage systems | |
| Kumar et al. | Analysis of integrated Boost-Cuk high voltage gain DC-DC converter with RBFN MPPT for solar PV application | |
| Sikder et al. | Incremental conductance based maximum power point tracking controller using different buck-boost converter for solar photovoltaic system | |
| CN111049188A (en) | Multi-input photovoltaic inverter system centralized mode MPPT method and application device thereof | |
| Luthfansyah et al. | Evaluation and comparison of DC-DC power converter variations in solar panel systems using maximum power point tracking (MPPT) flower pollination algorithm (FPA) Control | |
| Katayama et al. | Study on application of multi-level converter to realize fast current control in DC micro-grid with extremely low impedance interconnections | |
| Devika et al. | SEPIC-CUK Converter For PV Application Using Maximum Power Point Tracking Method | |
| WO2016209433A1 (en) | Hierarchical control of a plurality of power subsystems and method of operating the same | |
| Al‐Hitmi et al. | A hybrid switched inductor with flexible high voltage gain boost converter for DC micro‐grid application | |
| Chen et al. | Battery Current-Sharing Power Decoupling Method for Realizing a Single-Stage Hybrid PV System | |
| Farivar et al. | A simple perturb and observe MPPT scheme for Cascaded H-Bridge based photovoltaic system | |
| Raju et al. | Three phase multi-string boost front-end hybrid multilevel inverter for standalone system | |
| Uno et al. | Dual MPPT control and field testing for switched capacitor-based cell-level power balancing utilizing diffusion capacitance of photovoltaic cells |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200421 |
|
| RJ01 | Rejection of invention patent application after publication |