CN111009918A - Method and device for controlling power optimizer in photovoltaic grid-connected system - Google Patents
Method and device for controlling power optimizer in photovoltaic grid-connected system Download PDFInfo
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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Abstract
The invention provides a method and a device for controlling a power optimizer in a photovoltaic grid-connected system, wherein a plurality of components in the photovoltaic grid-connected system are respectively connected with the plurality of power optimizers in series and then are connected with a direct current bus of a photovoltaic inverter, and the method comprises the following steps: acquiring the current working state of a photovoltaic grid-connected system; under the condition that the working state of the photovoltaic grid-connected system is normal, switching back and forth among a plurality of working modes of the power optimizer to enable the sum of the output voltages of the power optimizer to be larger than the reference voltage of the direct-current bus; and the voltage for triggering the direct current bus distributes the voltage according to the output end power ratio of the plurality of power optimizers. According to the invention, the problem of overvoltage protection of the optimizer caused by too low speed of the communication system for adjusting the bus voltage when the illumination changes rapidly in the related art is solved.
Description
Technical Field
The invention relates to the field of electric power, in particular to a method and a device for controlling a power optimizer in a photovoltaic grid-connected system.
Background
In a series-connected Power optimizer photovoltaic grid-connected system, when Power is normally generated, a Power optimizer performs optimization of a component-level Maximum Power Point Tracking control solar controller (MPPT for short), a photovoltaic inverter controls bus voltage to be stable, and redundant generated energy is merged into a Power grid. In the system, when the photovoltaic grid-connected system normally and stably works, the voltage is distributed by the direct-current bus voltage according to the power ratio of the output end of the power optimizer, so that the power generation function of the photovoltaic grid-connected system can be completed only by the cooperative work of n power optimizers. Because the real-time change of environmental factors under the actual working condition causes the system parameters to change, the photovoltaic grid-connected system considering the series-connected power optimizer adopts a centralized control method with variable bus voltage. Each power optimizer is provided with an upper limit and a lower limit of output voltage, the output voltages of the power optimizers are different due to unbalanced illumination, and when the output voltage of the power optimizers reaches the upper limit or the lower limit, the reference of bus voltage is changed for the photovoltaic inverters through signals; when the optimizer does not pass through the upper limit or the lower limit of the output voltage, the bus voltage reference is unchanged. The control method can enable the system to work effectively, but when the power difference of different photovoltaic modules is large, the requirement on the communication system is high, when the illumination changes rapidly, the actual output voltage of the optimizer also changes rapidly, and if the speed of the communication system for adjusting the bus voltage is too slow, overvoltage protection of the optimizer can be caused.
In view of the above problems in the related art, no effective solution exists at present.
Disclosure of Invention
The embodiment of the invention provides a method and a device for controlling a power optimizer in a photovoltaic grid-connected system, which are used for at least solving the problem of overvoltage protection of the optimizer caused by too low speed of a communication system for adjusting bus voltage when illumination is changed rapidly in the related technology.
According to an embodiment of the present invention, there is provided a method for controlling a power optimizer in a photovoltaic grid-connected system, where a plurality of components in the photovoltaic grid-connected system are respectively connected in series with the plurality of power optimizers and then are connected to a dc bus of a photovoltaic inverter, including: acquiring the current working state of the photovoltaic grid-connected system; under the condition that the working state of the photovoltaic grid-connected system is normal, switching back and forth among a plurality of working modes of the power optimizer to enable the sum of the output voltages of the power optimizer to be larger than the reference voltage of a direct-current bus; and the voltage for triggering the direct current bus distributes voltage according to the output end power ratio of the plurality of power optimizers.
According to another embodiment of the present invention, there is provided an apparatus for controlling a power optimizer in a photovoltaic grid-connected system, in which a plurality of components in the photovoltaic grid-connected system are respectively connected in series with a plurality of power optimizers and then connected to a dc bus of a photovoltaic inverter, including: the acquisition module is used for acquiring the current working state of the photovoltaic grid-connected system; the control module is used for switching a plurality of working modes of the power optimizer back and forth under the condition that the working state of the photovoltaic grid-connected system is normal so that the sum of the output voltages of the power optimizer is larger than the reference voltage of a direct-current bus; and the distribution module is used for triggering the voltage of the direct current bus to distribute the voltage according to the power ratio of the output ends of the plurality of power optimizers.
According to another embodiment of the invention, the device comprises the above device for controlling the power optimizer in the photovoltaic grid-connected system.
According to a further embodiment of the present invention, there is also provided a storage medium having a computer program stored therein, wherein the computer program is arranged to perform the steps of any of the above method embodiments when executed.
According to the invention, under the condition that the working state of the photovoltaic grid-connected system is normal, the sum of the output voltages of the power optimizers is larger than the reference voltage of the direct current bus by switching the working modes of the power optimizers back and forth, and the voltage is further triggered to be distributed by the direct current bus voltage according to the output end power ratio of the power optimizers, so that the power optimizers are controlled without depending on the response speed of a communication system, and the problem of overvoltage protection of the optimizers caused by too low speed of the communication system for adjusting the bus voltage when the illumination changes rapidly in the related technology is solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
fig. 1 is a flowchart of a method of controlling a power optimizer in a grid-connected photovoltaic system according to an embodiment of the present invention;
fig. 2 is a schematic block diagram of a photovoltaic grid-connected system structure in the related art;
FIG. 3 is a schematic block diagram of a photovoltaic grid-connected system structure according to an embodiment of the invention;
fig. 4 is a block diagram of an apparatus for controlling a power optimizer in a photovoltaic grid-connected system according to an embodiment of the present invention.
Detailed Description
The invention will be described in detail hereinafter with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.
Example 1
In this embodiment, a method for controlling a power optimizer in a photovoltaic grid-connected system is provided, and fig. 1 is a flowchart of a method for controlling a power optimizer in a photovoltaic grid-connected system according to an embodiment of the present invention, as shown in fig. 1, the flowchart includes the following steps:
step S102, acquiring the current working state of the photovoltaic grid-connected system;
step S104, under the condition that the working state of the photovoltaic grid-connected system is normal, switching back and forth among a plurality of working modes of the power optimizer to enable the sum of the output voltages of the power optimizer to be larger than the reference voltage of the direct-current bus;
and step S106, the voltage of the direct current bus is triggered to be distributed according to the power ratio of the output ends of the plurality of power optimizers.
Through the steps S102 to S106, under the condition that the working state of the photovoltaic grid-connected system is normal, the sum of the output voltages of the plurality of power optimizers is greater than the reference voltage of the direct current bus by switching the plurality of working modes of the power optimizers back and forth, and then the voltage is distributed according to the output power ratio of the plurality of power optimizers by triggering the direct current bus voltage, so that the power optimizers are controlled without depending on the response speed of a communication system, and the problem of overvoltage protection of the optimizers caused by the fact that the speed of the communication system for adjusting the bus voltage is too slow when the illumination changes rapidly in the related art is solved.
In an optional implementation manner of this embodiment, as to the manner of obtaining the current operating state of the photovoltaic grid-connected system, which is referred to in step S102, the method further includes:
step S102-11, acquiring whether the voltage of the direct current bus is in a normal working state;
step S102-12, under the condition that the voltage of the direct current bus is in an abnormal working state, determining that the working state of the photovoltaic grid-connected system is abnormal;
step S102-13, under the condition that the voltage of the direct current bus is in a normal working state, whether the photovoltaic inverter works in a grid-connected state is obtained;
step S102-14, under the condition that the photovoltaic inverter works in a non-grid-connected state, determining that the working state of the photovoltaic grid-connected system is abnormal;
and S102-14, determining that the working state of the photovoltaic grid-connected system is normal under the condition that the photovoltaic inverter works in the grid-connected state.
As can be seen from the above steps S102-11 to S102-14, the working state of the photovoltaic grid-connected system needs to be determined by the working states of the dc bus and the photovoltaic inverter, and the photovoltaic grid-connected system is in the normal state only when both are in the normal state, and the photovoltaic grid-connected system is in the abnormal state when one of the two is in the abnormal working state.
As to the manner of acquiring whether the voltage of the dc bus is in the normal operating state or not in step S102-11, the following may be further performed:
step S11, determining that the voltage of the direct current bus is in an abnormal state under the condition that the voltage of the direct current bus is greater than or equal to a first preset voltage or the voltage of the direct current bus is less than or equal to a second preset voltage;
step S12, determining that the voltage of the direct current bus is in a normal state under the condition that the voltage of the direct current bus is greater than a second preset voltage and less than a first preset voltage; the first preset voltage is greater than the second preset voltage.
It should be noted that the first preset voltage is a maximum threshold voltage, and the second preset voltage is a minimum threshold voltage. That is, by determining whether the dc bus voltage is compared with the maximum threshold voltage and the minimum threshold voltage, the state is abnormal when the dc bus voltage is greater than the maximum threshold voltage or less than the minimum threshold voltage.
In another optional implementation manner of this embodiment, for the manner involved in step S104, switching back and forth between the multiple operation modes of the power optimizer so that the sum of the output voltages of the multiple power optimizers is greater than the dc bus reference voltage, further includes:
s1, determining the working mode of the power optimizer as a first working mode, wherein the voltage of the output side of the power optimizer is raised in the first working mode;
s2, under the condition that the voltage of the output side of the power optimizer is larger than a third preset voltage, the working mode of the power optimizer is converted into a second working mode from the first working mode; lowering the low power optimizer output side voltage in the case of the second mode of operation;
s3, when the output side voltage of the power optimizer is smaller than the fourth preset voltage, repeating the steps S1 and S2 to make the sum of the output voltages of the plurality of power optimizers larger than the dc bus reference voltage; wherein the third preset voltage is greater than the fourth preset voltage.
It should be noted that, in a specific application scenario, the first operating mode and the second operating mode may be: MPPT mode of operation, direct mode of operation. Therefore, for the above steps S1 to S3, in a specific application scenario, may be: the power optimizer firstly works in an MPPT mode, the voltage of an output side is increased, and when the voltage of the output side is larger than Vpv _ max, the power optimizer works in a direct mode by detecting the voltage of the output side in real time; when the power optimizer works in a direct mode, the voltage of an output side slowly drops from Vpv _ max, when the voltage of the output side drops to be less than Vpv _ min, the power optimizer works in an MPPT mode, the power optimizer works in a direct-MPPT cyclic reciprocating process until the sum of the output voltages of the plurality of power optimizers is greater than the reference voltage of a direct current bus and then stably works in the MPPT mode, and a system normally generates and is connected to the grid.
In another optional implementation manner of this embodiment, the method of this embodiment may further include: and under the condition that the working state of the photovoltaic grid-connected system is abnormal, determining that the working mode of the power optimizer is a third working mode, wherein the third working mode is a stop working mode.
It should be noted that the third operating mode may be a shutdown mode in a specific application scenario, that is, when the dc bus voltage is less than the minimum threshold voltage or greater than the maximum threshold voltage, the power optimizer enters the shutdown mode.
The present application will be illustrated with reference to alternative embodiments of the present embodiment;
first, a conventional photovoltaic grid-connected system in the prior art is introduced, as shown in fig. 2, an output positive electrode of each component in the conventional photovoltaic grid-connected system is connected to an output negative electrode of a next component. The n block assemblies (PV1, PV2, … … and PVn) form a group string in a series connection mode and then are connected into a direct current bus of a photovoltaic inverter (bidirectional DC-AC) with an MPPT function, in order to utilize photovoltaic Power generation energy to the Maximum, a Maximum Power Point Tracking (MPPT) algorithm is generally adopted to ensure that the photovoltaic group string works in a Maximum Power generation capacity state, and the system photovoltaic Power generation amount is fed into a Power grid through the photovoltaic inverter.
In the photovoltaic grid-connected system integrated with the power optimizer in this optional embodiment, as shown in fig. 3, after the n blocks of modules (PV1, PV2, … …, PVn) are integrated with the power optimizer, the modules are connected in series to form a photovoltaic string system, and then a DC bus of a photovoltaic inverter (bidirectional DC-AC) is connected. Because the power optimizer is provided with the MPPT function at the component level, the bidirectional DC-AC system is not provided with the MPPT function, and the photovoltaic power generation amount of the system is fed into a power grid through a photovoltaic inverter. The photovoltaic inverter and the power optimizer have a direct current power line carrier communication (PLC) function, the photovoltaic inverter end is used for receiving and analyzing state data of each power optimizer and sending a control instruction to each power optimizer, and the power optimizer end is used for receiving the control instruction data of the photovoltaic inverter and sending state data of the power optimizer. Since the power optimizer is already equipped with component level MPPT functionality, the bi-directional DC-AC system does not have MPPT functionality. The power optimizer is mainly responsible for the function of MPPT and the photovoltaic inverter controls the dc bus voltage and output current to maintain power balance between the two stages.
Based on fig. 3, the present optional embodiment provides a control method for a tandem power optimizer in a photovoltaic grid-connected system, in the control method, the power optimizer has three operation modes, including an MPPT operation mode, a pass-through operation mode, and a shutdown mode.
The method comprises the steps that a minimum threshold value Vdc _ min and a maximum threshold value Vdc _ max are set for the voltage of a direct current bus, a reference value is dynamically adjustable within the interval [ Vdc _ min and Vdc _ max ] of the voltage of the direct current bus, a minimum threshold value Vpv _ min and a maximum threshold value Vpv _ max are set for the output end of a power optimizer according to the voltage interval and the serial number of the direct current bus, and the voltage of the output end of the power optimizer is dynamically adjustable within the interval [ Vpv _ min and Vpv _ max ].
When the direct-current bus voltage is smaller than Vdc _ min or larger than Vdc _ max, the power optimizer enters a shutdown mode; when the direct-current bus voltage is larger than Vdc _ min and smaller than Vdc _ max, the power optimizer analyzes the photovoltaic inverter to work in a conventional grid-connected state through PLC power carrier communication data. The power optimizer firstly works in an MPPT mode, the voltage of an output side is increased, and when the voltage of the output side is larger than Vpv _ max, the power optimizer works in a direct mode by detecting the voltage of the output side in real time; when the power optimizer works in a direct mode, the voltage of an output side slowly drops from Vpv _ max, when the voltage of the output side drops to be less than Vpv _ min, the power optimizer works in an MPPT mode, the power optimizer works in a direct-MPPT cyclic reciprocating process until the sum of the output voltages of the plurality of power optimizers is greater than the reference voltage of a direct current bus and then stably works in the MPPT mode, a system normally generates power and is connected to the grid, and the voltage of the direct current bus is distributed according to the power ratio of the output end of the power optimizer. And if the photovoltaic inverter enters a non-grid-connected state or a direct current bus abnormal state, the power optimizer works in a shutdown mode. The power optimizer monitors the working mode of the photovoltaic inverter in real time through PLC communication data, when the working mode of the photovoltaic inverter is not changed for the last time, the working mode of the power optimizer is kept unchanged, and when the working mode of the photovoltaic inverter is changed for the last time, the working mode of the power optimizer is adjusted and switched in real time.
By the control method of the series power optimizer in the photovoltaic grid-connected system, the response speed of the communication system is not required in the photovoltaic grid-connected system integrated with the series power optimizer, and the overvoltage protection problem of the optimizer is caused by the fact that the speed of the communication system for adjusting the bus voltage is too low when the illumination changes rapidly.
Through the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but the former is a better implementation mode in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (e.g., a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present invention.
Example 2
The embodiment also provides a device for controlling a power optimizer in a photovoltaic grid-connected system, and the device is used for implementing the above embodiments and preferred embodiments, and the description of the device is omitted. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated.
Fig. 4 is a block diagram of an apparatus for controlling a power optimizer in a photovoltaic grid-connected system according to an embodiment of the present invention, wherein a plurality of components in the photovoltaic grid-connected system are respectively connected in series with a plurality of power optimizers and then connected to a dc bus of a photovoltaic inverter, as shown in fig. 4, the apparatus includes:
(1) the acquiring module 42 is used for acquiring the current working state of the photovoltaic grid-connected system;
(2) the control module 44 is configured to switch back and forth between a plurality of working modes of the power optimizer so that the sum of output voltages of the plurality of power optimizers is greater than the reference voltage of the direct-current bus when the working state of the photovoltaic grid-connected system is normal;
(3) and the distribution module 46 is used for distributing the voltage of the trigger direct current bus according to the output end power ratio of the plurality of power optimizers.
Optionally, the obtaining module 42 in this embodiment further includes: the first acquisition unit is used for acquiring whether the voltage of the direct current bus is in a normal working state; the first determining unit is used for determining that the working state of the photovoltaic grid-connected system is abnormal under the condition that the voltage of the direct-current bus is in an abnormal working state; the second acquisition unit is used for acquiring whether the photovoltaic inverter works in a grid-connected state or not under the condition that the voltage of the direct-current bus is in a normal working state; the second determining unit is used for determining that the working state of the photovoltaic grid-connected system is abnormal under the condition that the photovoltaic inverter works in a non-grid-connected state; and the third determining unit is used for determining that the working state of the photovoltaic grid-connected system is normal under the condition that the photovoltaic inverter works in the grid-connected state.
Optionally, the first obtaining unit in this embodiment may further include: the first determining subunit is used for determining that the voltage of the direct current bus is in an abnormal state under the condition that the voltage of the direct current bus is greater than or equal to a first preset voltage or the voltage of the direct current bus is less than or equal to a second preset voltage; the second determining subunit is used for determining that the voltage of the direct current bus is in a normal state under the condition that the voltage of the direct current bus is greater than a second preset voltage and smaller than a first preset voltage; the first preset voltage is greater than the second preset voltage.
Optionally, the control module 44 in this embodiment is configured to perform the following steps:
s1, determining the working mode of the power optimizer as a first working mode, wherein the voltage of the output side of the power optimizer is raised in the first working mode;
s2, under the condition that the voltage of the output side of the power optimizer is larger than a third preset voltage, the working mode of the power optimizer is converted into a second working mode from the first working mode; lowering the low power optimizer output side voltage in the case of the second mode of operation;
s3, when the output side voltage of the power optimizer is smaller than the fourth preset voltage, repeating the steps S1 and S2 to make the sum of the output voltages of the plurality of power optimizers larger than the dc bus reference voltage; wherein the third preset voltage is greater than the fourth preset voltage.
Optionally, the obtaining module 42 in this embodiment further includes: and the fourth determining unit is used for determining that the working mode of the power optimizer is a third working mode under the condition that the working state of the photovoltaic grid-connected system is abnormal, wherein the third working mode is a stop working mode.
It should be noted that, the above modules may be implemented by software or hardware, and for the latter, the following may be implemented, but not limited to: the modules are all positioned in the same processor; alternatively, the modules are respectively located in different processors in any combination.
Example 3
Embodiments of the present invention also provide a storage medium having a computer program stored therein, wherein the computer program is arranged to perform the steps of any of the above method embodiments when executed.
Alternatively, in the present embodiment, the storage medium may be configured to store a computer program for executing the steps of:
s1, acquiring the current working state of the photovoltaic grid-connected system;
s2, under the condition that the working state of the photovoltaic grid-connected system is normal, switching back and forth among a plurality of working modes of the power optimizer to enable the sum of the output voltages of the power optimizer to be larger than the reference voltage of the direct-current bus;
and S3, the voltage of the direct current bus is triggered to be distributed according to the output end power ratio of the plurality of power optimizers.
Optionally, in this embodiment, the storage medium may include, but is not limited to: various media capable of storing computer programs, such as a usb disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic disk, or an optical disk.
Embodiments of the present invention also provide an electronic device comprising a memory having a computer program stored therein and a processor arranged to run the computer program to perform the steps of any of the above method embodiments.
Optionally, the electronic apparatus may further include a transmission device and an input/output device, wherein the transmission device is connected to the processor, and the input/output device is connected to the processor.
Optionally, in this embodiment, the processor may be configured to execute the following steps by a computer program:
s1, acquiring the current working state of the photovoltaic grid-connected system;
s2, under the condition that the working state of the photovoltaic grid-connected system is normal, switching back and forth among a plurality of working modes of the power optimizer to enable the sum of the output voltages of the power optimizer to be larger than the reference voltage of the direct-current bus;
and S3, the voltage of the direct current bus is triggered to be distributed according to the output end power ratio of the plurality of power optimizers.
Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation manners, and this embodiment is not described herein again.
It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for controlling a power optimizer in a photovoltaic grid-connected system, wherein a plurality of components in the photovoltaic grid-connected system are respectively connected with a plurality of power optimizers in series and then are connected with a direct current bus of a photovoltaic inverter, and the method is characterized by comprising the following steps:
acquiring the current working state of the photovoltaic grid-connected system;
under the condition that the working state of the photovoltaic grid-connected system is normal, switching back and forth among a plurality of working modes of the power optimizer to enable the sum of the output voltages of the power optimizer to be larger than the reference voltage of a direct-current bus;
and the voltage for triggering the direct current bus distributes voltage according to the output end power ratio of the plurality of power optimizers.
2. The method according to claim 1, wherein obtaining the current working state of the photovoltaic grid-connected system comprises:
acquiring whether the voltage of the direct current bus is in a normal working state;
under the condition that the voltage of the direct current bus is in an abnormal working state, determining that the working state of the photovoltaic grid-connected system is abnormal;
under the condition that the voltage of the direct current bus is in a normal working state, whether the photovoltaic inverter works in a grid-connected state or not is obtained;
under the condition that the photovoltaic inverter works in a non-grid-connected state, determining that the working state of the photovoltaic grid-connected system is abnormal;
and under the condition that the photovoltaic inverter works in a grid-connected state, determining that the working state of the photovoltaic grid-connected system is normal.
3. The method of claim 2, wherein obtaining whether the voltage of the dc bus is in a normal operating state comprises:
determining that the voltage of the direct current bus is in an abnormal state under the condition that the voltage of the direct current bus is greater than or equal to a first preset voltage or the voltage of the direct current bus is less than or equal to a second preset voltage;
determining that the voltage of the direct current bus is in a normal state under the condition that the voltage of the direct current bus is greater than the second preset voltage and less than the first preset voltage;
wherein the first preset voltage is greater than the second preset voltage.
4. The method of claim 1, wherein switching back and forth between the plurality of operating modes of the power optimizer such that a sum of output voltages of the plurality of power optimizers is greater than the dc bus reference voltage comprises:
s1, determining the working mode of the power optimizer as a first working mode, wherein the voltage of the output side of the power optimizer is raised in the first working mode;
s2, when the voltage of the output side of the power optimizer is larger than a third preset voltage, the working mode of the power optimizer is converted from a first working mode to a second working mode; reducing the power optimizer output side voltage in the case of the second mode of operation;
s3, when the output side voltage of the power optimizer is smaller than a fourth preset voltage, repeatedly executing the steps S1 and S2 to make the sum of the output voltages of the power optimizers larger than the dc bus reference voltage;
wherein the third preset voltage is greater than the fourth preset voltage.
5. The method of claim 2,
and under the condition that the working state of the photovoltaic grid-connected system is abnormal, determining that the working mode of the power optimizer is a third working mode, wherein the third working mode is a stop working mode.
6. The utility model provides a device of power optimizer in control photovoltaic grid-connected system, a plurality of subassemblies in the photovoltaic grid-connected system insert photovoltaic inverter's direct current generating line after establishing ties with a plurality of power optimizer respectively which characterized in that includes:
the acquisition module is used for acquiring the current working state of the photovoltaic grid-connected system;
the control module is used for switching a plurality of working modes of the power optimizer back and forth under the condition that the working state of the photovoltaic grid-connected system is normal so that the sum of the output voltages of the power optimizer is larger than the reference voltage of a direct-current bus;
and the distribution module is used for triggering the voltage of the direct current bus to distribute the voltage according to the power ratio of the output ends of the plurality of power optimizers.
7. The apparatus of claim 6, wherein the obtaining module comprises:
the first acquisition unit is used for acquiring whether the voltage of the direct current bus is in a normal working state or not;
the first determining unit is used for determining that the working state of the photovoltaic grid-connected system is abnormal under the condition that the voltage of the direct-current bus is in an abnormal working state;
the second acquisition unit is used for acquiring whether the photovoltaic inverter works in a grid-connected state or not under the condition that the voltage of the direct-current bus is in a normal working state;
the second determining unit is used for determining that the working state of the photovoltaic grid-connected system is abnormal under the condition that the photovoltaic inverter works in a non-grid-connected state;
and the third determining unit is used for determining that the working state of the photovoltaic grid-connected system is normal under the condition that the photovoltaic inverter works in the grid-connected state.
8. The apparatus of claim 6, wherein the control module is configured to perform the steps of:
s1, determining the working mode of the power optimizer as a first working mode, wherein the voltage of the output side of the power optimizer is raised in the first working mode;
s2, when the voltage of the output side of the power optimizer is larger than a third preset voltage, the working mode of the power optimizer is converted from a first working mode to a second working mode; reducing the power optimizer output side voltage in the case of the second mode of operation;
s3, when the output side voltage of the power optimizer is smaller than a fourth preset voltage, repeatedly executing the steps S1 and S2 to make the sum of the output voltages of the power optimizers larger than the dc bus reference voltage;
wherein the third preset voltage is greater than the fourth preset voltage.
9. An apparatus comprising the device of any one of claims 6 to 8.
10. A storage medium, in which a computer program is stored, wherein the computer program is arranged to perform the method of any of claims 1 to 5 when executed.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104079001A (en) * | 2014-07-15 | 2014-10-01 | 浙江大学 | Optimizer control method based on series-type optimizers in photovoltaic grid-connected system |
| CN105474406A (en) * | 2013-04-13 | 2016-04-06 | 速力斯公司 | Smart photovoltaic cells and modules |
| WO2017087988A1 (en) * | 2015-11-19 | 2017-05-26 | Beamreach Solar, Inc. | Multi-modal maximum power point tracking optimzation solar photovoltaic system |
| CN107154780A (en) * | 2017-06-08 | 2017-09-12 | 阳光电源股份有限公司 | A kind of photovoltaic generating system and its Poewr control method and power optimization device |
| CN107370187A (en) * | 2017-09-08 | 2017-11-21 | 中南大学 | A kind of photovoltaic microgrid system and photovoltaic microgrid system control method |
| CN109672166A (en) * | 2017-10-17 | 2019-04-23 | 丰郅(上海)新能源科技有限公司 | Power optimized system and its optimization method |
| CN110492592A (en) * | 2019-09-06 | 2019-11-22 | 珠海格力电器股份有限公司 | DC micro power grid system progress control method and device |
-
2019
- 2019-12-13 CN CN201911284933.7A patent/CN111009918A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105474406A (en) * | 2013-04-13 | 2016-04-06 | 速力斯公司 | Smart photovoltaic cells and modules |
| CN104079001A (en) * | 2014-07-15 | 2014-10-01 | 浙江大学 | Optimizer control method based on series-type optimizers in photovoltaic grid-connected system |
| WO2017087988A1 (en) * | 2015-11-19 | 2017-05-26 | Beamreach Solar, Inc. | Multi-modal maximum power point tracking optimzation solar photovoltaic system |
| CN107154780A (en) * | 2017-06-08 | 2017-09-12 | 阳光电源股份有限公司 | A kind of photovoltaic generating system and its Poewr control method and power optimization device |
| CN107370187A (en) * | 2017-09-08 | 2017-11-21 | 中南大学 | A kind of photovoltaic microgrid system and photovoltaic microgrid system control method |
| CN109672166A (en) * | 2017-10-17 | 2019-04-23 | 丰郅(上海)新能源科技有限公司 | Power optimized system and its optimization method |
| CN110492592A (en) * | 2019-09-06 | 2019-11-22 | 珠海格力电器股份有限公司 | DC micro power grid system progress control method and device |
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