Disclosure of Invention
In order to solve the problem of service life of a shielded cell in the prior art, the embodiment of the invention provides a control method and a control device of a photovoltaic module. The technical scheme is as follows:
in a first aspect, a photovoltaic module is provided, the photovoltaic module comprising a photovoltaic module anode, a photovoltaic module cathode, and a plurality of cell string assemblies, each cell string assembly comprising a cell string, a first switching element, and a second switching element, wherein:
a plurality of the first switching elements in the plurality of cell string assemblies are connected in series between the photovoltaic assembly positive electrode and the photovoltaic assembly negative electrode;
the first end of a battery string in any battery string assembly is connected with the first passage end of a second switch element in any battery string assembly, the second passage end of the second switch element in any battery string assembly is connected with the first passage end of the first switch element in any battery string assembly, and the second end of the battery string in any battery string assembly is connected with the second passage end of the first switch element in any battery string assembly.
In a second aspect, a control method for a photovoltaic module is provided, the photovoltaic module further includes a current detection device for detecting a current value between a positive electrode of the photovoltaic module and a negative electrode of the photovoltaic module, the method includes:
acquiring a first current value detected by the current detection device;
controlling a battery string in at least one test battery string assembly to enter an open circuit state, wherein the test battery string assembly is any one or two or all of the plurality of battery string assemblies;
acquiring a second current value detected by the current detection device, and determining whether shielding exists in the at least one test battery string component according to the first current value and the second current value;
if the at least one test battery string component has shielding, controlling a battery string in the at least one test battery string component to keep an open circuit state;
when a battery string in the battery string assembly enters an open-circuit state, the first switch element is switched on, and the second switch element is switched off; when the battery string assembly enters a working state, the first switch element is switched off, and the second switch element is switched on.
Optionally, the determining whether there is a blockage in the at least one test battery string assembly according to the first current value and the second current value includes:
calculating a first difference between the second current value and the first current value;
and if the first difference value reaches a preset threshold value, judging that the at least one test battery string component has occlusion.
Optionally, a ratio of the predetermined threshold to a maximum power point current of the photovoltaic module is greater than 5%.
Optionally, after controlling the battery string in the at least one test battery string assembly to maintain the open-circuit state, the method further includes:
when the duration of the battery string in the at least one test battery string assembly in the open circuit state reaches a preset duration, controlling the battery string in the at least one test battery string assembly to be switched from the open circuit state to a working state;
acquiring a current detected by the current detection device before switching to a working state as a third current value, and a current detected by the current detection device after switching to the working state as a fourth current value, and calculating a second difference value between the fourth current value and the third current value;
if the second difference value is larger than 0 and lower than the preset threshold value, controlling the at least one test battery string assembly to keep in a working state;
and if the second difference is less than 0, controlling the at least one test battery string component to enter an open-circuit state.
In a third aspect, a computer-readable storage medium is provided, where one or more instructions are stored in the computer-readable storage medium, and when executed by a processor in a photovoltaic module, the one or more instructions implement the second aspect and the control method for the photovoltaic module according to any optional implementation manner of the second aspect.
In a fourth aspect, a control device for a photovoltaic module is provided, the control device comprising:
a memory and a processor;
at least one program instruction is stored in the memory;
the processor is configured to load and execute the at least one program instruction to implement the control method for the photovoltaic module according to the second aspect and any optional embodiment of the second aspect.
The technical scheme provided by the embodiment of the invention has the following beneficial effects:
by providing a photovoltaic module comprising a photovoltaic module positive electrode, a photovoltaic module negative electrode and a plurality of cell string assemblies, each cell string assembly comprising a cell string, a first switching element and a second switching element, wherein: all the first switching elements in the plurality of battery string assemblies are connected in series between the positive pole of the photovoltaic assembly and the negative pole of the photovoltaic assembly; a first end of a battery string in any battery string assembly is connected with a first path end of a second switch element in any battery string assembly, a second path end of the second switch element in any battery string assembly is connected with a first path end of a first switch element in any battery string assembly, and a second end of the battery string in any battery string assembly is connected with a second path end of the first switch element in any battery string assembly; the problem that in the related art, the battery string where the shielded battery piece is located is bypassed, the shielded battery piece still generates heat, and the service life of the shielded battery piece is shortened is solved; the effect of prolonging the service life of the cell in the photovoltaic module is achieved.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of a photovoltaic module according to an exemplary embodiment of the present invention. As shown in fig. 1, the photovoltaic module includes a photovoltaic module positive electrode, a photovoltaic module negative electrode, and a plurality of cell string assemblies 10, each cell string assembly 10 includes a cell string 11, a first switching element 12, and a second switching element 13, wherein:
all the first switching elements 12 in the plurality of cell string assemblies are connected in series between the positive pole of the photovoltaic assembly and the negative pole of the photovoltaic assembly; a first end of a battery string in any one of the battery string assemblies is connected to a first path end of the second switching element 13 in the any one of the battery string assemblies, a second path end of the second switching element 13 in the any one of the battery string assemblies is connected to a first path end of the first switching element 12 in the any one of the battery string assemblies, and a second end of the battery string in the any one of the battery string assemblies is connected to a second path end of the first switching element 12 in the any one of the battery string assemblies.
For example, referring to fig. 1, the photovoltaic module shown in fig. 1 includes 3 cell string assemblies, one end of a cell string in each cell string assembly is connected to one end of a first switch element 12, and the other end of the first switch element 12 is connected to the other end of the cell string through a second switch element 13.
When the first switch element 12 in each battery string assembly is turned on and the second switch element 13 is turned off, the battery string in the battery string assembly is in an open circuit state and stops working; when the first switching element 12 of each cell string module is turned off and the second switching element 13 is turned on, the cell string of the cell string module enters an operating state and can generate power.
According to the photovoltaic module provided by the invention, when a cell in any cell string is shielded to generate hot spots, the first switch element in the cell string component in which the cell string is located is switched on, and the second switch element is switched off, so that the cell string is separated from the loop of the photovoltaic module, and the cell string is in an open circuit state and does not heat any more; the problem that in the related art, the battery string where the shielded battery piece is located is bypassed, the shielded battery piece still generates heat, and the service life of the shielded battery piece is shortened is solved; the effect of prolonging the service life of the cell in the photovoltaic module is achieved.
When hot spots are generated on any battery string, the battery string can be controlled to enter an open circuit state by controlling the first switch element and the second switch element 13 in the battery string component where the battery string is located, so that the shielded battery pieces in the battery string can not generate heat any more to eliminate the hot spots on the battery string.
Optionally, each first switch element 12 and each second switch element 13 in the plurality of cell string assemblies are electronic switches, and the control terminals are respectively electrically connected with the processor in the photovoltaic assembly, and the processor controls on/off of each switch element 12 and each second switch element 13.
Optionally, the photovoltaic module further includes a current detection device (not shown in the figure) for detecting a current value between the positive electrode and the negative electrode of the photovoltaic module, the current detection device is electrically connected to the processor, and the processor controls the state of each battery string in the photovoltaic module according to the current value detected by the current detection device, so as to control the battery string generating the hot spot to enter an open circuit state to eliminate the hot spot on the photovoltaic module.
Optionally, the first switch element 12 and the second switch element 13 may be electronic switches, such as Metal-Oxide-Semiconductor Field-effect transistors (MOSFETs).
Optionally, the photovoltaic module related to the present application may be a back plate assembly, a dual glass assembly, and the like, and this embodiment is not particularly limited thereto.
Referring to fig. 2, a flowchart of a method for controlling a photovoltaic module according to an embodiment of the present invention is shown, and the embodiment is exemplified by the method for controlling the photovoltaic module. As shown in fig. 2, the control method of the photovoltaic module may include:
step 210, obtaining a first current value detected by the current detection device.
Step 220, controlling a battery string in at least one test battery string assembly to enter an open circuit state, wherein the test battery string assembly is any one, two or all of the plurality of battery string assemblies.
Step 230, obtaining a second current value detected by the current detection device, and determining whether a block exists in the at least one test battery string assembly according to the first current value and the second current value.
And 240, if the at least one test battery string component has shielding, controlling the battery string in the at least one test battery string component to keep an open circuit state.
In summary, in the method provided in the embodiment of the present invention, the first current value detected by the current detection device is obtained; controlling a battery string in at least one test battery string component to enter an open circuit state, wherein the test battery string component is any one or two or all of the plurality of battery string components; acquiring a second current value detected by the current detection device, and determining whether shielding exists in the at least one test battery string component according to the first current value and the second current value; if the at least one test battery string component has shielding, controlling the battery string in the at least one test battery string component to keep an open circuit state; the effect of eliminating hot spots in the photovoltaic module is achieved.
Referring to fig. 3, a flowchart of a method for controlling a photovoltaic module according to another embodiment of the present invention is shown, and the present embodiment is exemplified by the method for controlling the photovoltaic module. As shown in fig. 3, the control method of the photovoltaic module may include:
in step 310, a first current value detected by the current detection device is obtained.
And 320, controlling a battery string in at least one test battery string assembly to enter an open circuit state, wherein the test battery string assembly is any one, two or all of the plurality of battery string assemblies.
The implementation of this step can be: and selecting at least one test battery string assembly from the photovoltaic assemblies, and controlling the battery strings in the at least one test battery string assembly to enter an open circuit state.
Optionally, one test battery string assembly is selected from the photovoltaic assemblies, and the battery string in the test battery string assembly is controlled to enter an open circuit state. For example, referring to fig. 1, a battery string assembly in which a battery string a is located is selected from the photovoltaic assembly as a test battery string assembly, the battery string a is controlled to enter an open circuit state, and a second current value detected by the current detection device is obtained again; step 330 is again performed to determine if there is an occlusion on cell a.
The points to be explained are: in the application, before the cell strings in the test cell string assembly in the photovoltaic assembly are controlled to enter the open circuit state, the cell strings in other cell string assemblies in the photovoltaic assembly are also controlled to enter the working state.
Step 330, obtaining a second current value detected by the current detection device, and determining whether a block exists in the at least one test battery string assembly according to the first current value and the second current value.
Optionally, the step may be implemented as follows: calculating a first difference between the second current value and the first current value; if the first difference reaches a predetermined threshold, it is determined that a blockage exists in the at least one test battery string assembly.
For example, if there is a blockage on the battery string a, the current on the battery string a is small, which results in a current value detected by the current detection device being smaller than a current value detected by the current detection device when the photovoltaic module is not blocked. In the application, a first difference value between a second current value and the first current value is calculated; if the first difference reaches a predetermined threshold, it is determined that an occlusion exists in the at least one test string assembly (e.g., string A in this example).
Optionally, a ratio of the predetermined threshold to a maximum power point current of the photovoltaic module is greater than 5%.
After step 330 is performed, either step 340 or step 350 is performed.
And 340, if the at least one test battery string component has shielding, controlling the battery string in the at least one test battery string component to keep an open circuit state.
For example, if the battery string a has a shield, the battery string a is controlled to maintain an open state to eliminate hot spots on the battery string a.
Optionally, in the present application, at least one battery string component may be selected from the photovoltaic components as a test battery string component multiple times, and the test battery string component may be selected according to a predetermined rule, where the predetermined rule may include an identifier of the at least one battery string component corresponding to the nth selection. For example, the 1 st time corresponding cell string a, the second time corresponding cell string B, the 3 rd time corresponding cell string C, the 4 th time corresponding cell string a and cell string B, the 5 th time corresponding cell string a and cell string C, and the 6 th time corresponding cell string B and cell string C.
Optionally, in the present application, before a battery string with a block is not detected, the battery strings in the photovoltaic module are detected one by one (a detection sequence may be set by a system developer); in the application, when the shielding exists on any battery string, the battery string component where the battery string is located and the battery string components where other battery strings which are adjacent/non-adjacent to the battery string and not detected are located can be determined as the test battery string components.
Optionally, in the present application, at least one battery string component may be selected from the photovoltaic components multiple times as a test battery string component, and the battery strings in the photovoltaic components may be detected one by one (the detection sequence may be set by a system developer) until hot spots on the photovoltaic components are eliminated; if the hot spots are not eliminated after the cell strings in the photovoltaic module are detected one by one, the cell string groups in the photovoltaic module can be detected one by one (two or more adjacent/nonadjacent cell strings on the photovoltaic module are in one group, and the detection sequence is set by a system developer).
Step 350, if there is no occlusion in the at least one test cell string component, reselecting at least one cell string component from the photovoltaic component as a test cell string component, and performing step 310.
For example, if the battery string a is not shielded, the battery string B is selected from the photovoltaic module as a test battery string module, and the battery string a is controlled to enter a working state; step 310 is executed again to detect whether there is a blockage in the battery string B.
In summary, in the method provided in the embodiment of the present invention, the first current value detected by the current detection device is obtained; controlling a battery string in at least one test battery string component to enter an open circuit state, wherein the test battery string component is any one or two or all of the plurality of battery string components; acquiring a second current value detected by the current detection device, and determining whether shielding exists in the at least one test battery string component according to the first current value and the second current value; if the at least one test battery string component has shielding, controlling the battery string in the at least one test battery string component to keep an open circuit state; the effect of eliminating hot spots in the photovoltaic module is achieved.
Step 410, when the duration of the battery string in the at least one test battery string assembly maintaining the open circuit state reaches a preset duration, controlling the battery string in the at least one test battery string assembly to switch from the open circuit state to the working state.
Step 420, obtaining the current detected by the current detecting device before switching to the working state as a third current value and the current detected by the current detecting device after switching to the working state as a fourth current value, and calculating a second difference between the fourth current value and the third current value.
And 430, if the second difference is greater than 0 and lower than the predetermined threshold, controlling the at least one test battery string assembly to keep working.
And if the second difference is larger than 0 and lower than the preset threshold value, the obstruction on the battery string, which causes the hot spot, is eliminated, and the at least one test battery string component is controlled to keep the working state.
Step 440, if the second difference is smaller than 0, controlling the at least one test battery string assembly to enter an open-circuit state.
And if the second difference is less than 0, indicating that the shade on the battery string causing the hot spot is not eliminated, and controlling the at least one test battery string component to keep an open circuit state.
For the convenience of understanding, a cell string detection process of the photovoltaic module is illustrated by taking an example; referring to fig. 1, the photovoltaic module includes a cell string a, a cell string B, and a cell string C.
①, controlling the battery string A to enter an open circuit state, and executing the second step or the third step.
if delta I (current change value detected by the current detection device) before and after the battery string A is detected to be larger than 5% of Ipm (the Ipm is the maximum power point current of the photovoltaic module), the battery string A is controlled to enter a working state after a preset time interval, the delta I before and after the battery string A enters the working state is detected, if the delta I is smaller than 5% of the Ipm, the battery string A is kept in the working state, and if the delta I is a negative value, the battery string A is controlled to enter an open circuit state.
if the delta I is detected to be less than 5% of Ipm, the battery string A is controlled to enter a working state, and the battery string B enters a broken circuit state, and ④ or a fifth step is executed.
if delta I (current change value detected by the current detection device) before and after the battery string B is detected to be larger than 5% of Ipm (Ipm is the maximum power point current of the photovoltaic module), the battery string B is kept in the state, the battery string B is controlled to enter the working state after a preset time interval, the delta I before and after the battery string B enters the working state is detected, if the delta I is smaller than 5% of the Ipm, the battery string B is kept in the working state, and if the delta I is a negative value, the battery string B is controlled to enter the open circuit state.
and fifthly, if delta I before and after the battery string B is disconnected is detected to be less than 5% of Ipm, controlling the battery string B to enter a working state, controlling the battery string C to enter a disconnection state, and executing ⑥ or seventh.
after a preset time interval, controlling the battery string C to enter a working state, and simultaneously detecting the delta I before and after the battery string C enters the working state, if the delta I is less than 5% of the Ipm, keeping the battery string C in the working state, and if the delta I is a negative value, controlling the battery string C to enter a broken circuit state;
and if delta I < 5% Ipm before and after the disconnection of the battery string C is detected, controlling the battery string C to enter a working state, controlling the battery string A and the battery string B to enter the working state, and executing the operation (B) or (C).
if delta I (current change value detected by a current detection device) before and after the disconnection of the battery string A and the battery string B is detected to be larger than 5% Ipm (Ipm is maximum power point current of the photovoltaic module), the battery string A and the battery string B are controlled to enter a working state after a preset time interval, the delta I before and after the battery string A and the battery string B enter the working state is detected at the same time, if the delta I is smaller than 5% Ipm, the battery string A and the battery string B are kept in the working state, and if the delta I is a negative value, the battery string A and the battery string B are controlled to enter the disconnection state.
ninthly if detecting Δ I (current change value detected by the current detecting means) before and after the disconnection of the battery string A and the battery string B<5% Ipm, battery string A is controlled to enter the working state, and battery strings B and C enter the open-circuit state, and the operation is performed in the R or R
and controlling the battery string B and the battery string C to enter a working state after a preset time interval, simultaneously detecting the delta I before and after the battery string B and the battery string C enter the working state, if the delta I is less than 5% of the Ipm, keeping the battery string B and the battery string C in the working state, and if the delta I is a negative value, controlling the battery string B and the battery string C to enter a broken state.
When Δ I (current change value detected by the current detection device) before and after disconnection of the battery string B and the battery string C is detected<5% Ipm, the battery string B is controlled to enter the working state, the battery string A and the battery string C enter the open circuit state, and the execution is carried out
Or
When Δ I (current change value detected by the current detection device) before and after disconnection of the battery string A and the battery string C is detected>5% Ipm (Ipm is the maximum power point current of the photovoltaic module), this state is maintained; controlling the battery string A and the battery string C to enter a working state after a preset time interval, simultaneously detecting delta I before and after the battery string A and the battery string C enter the working state, and if the delta I is detected<And 5% of Ipm keeps the battery string A and the battery string C in the working state, and controls the battery string A and the battery string C to enter the open-circuit state if delta I is a negative value.
When Δ I (current change value detected by the current detection device) before and after disconnection of the battery string A and the battery string C is detected<controlling the battery string A, the battery string B and the battery string C to enter an open-circuit state by 5% of Ipm, controlling the battery string A to enter a working state at intervals of a preset time after controlling the battery string A, the battery string B and the battery string C to enter the open-circuit state, controlling the battery string B to enter the working state at intervals of the preset time, controlling the battery string C to enter the working state at intervals of the preset time, and repeatedly executing the first step
An embodiment of the present invention further provides a computer-readable storage medium, in which one or more instructions are stored, and when executed by a processor in a photovoltaic module, the one or more instructions implement the control method of the photovoltaic module in any of the above embodiments.
An embodiment of the present invention further provides a control apparatus for a photovoltaic module, including: a memory and a processor; at least one program instruction is stored in the memory; the processor is used for realizing the control method of the photovoltaic module related in any one of the above embodiments by loading and executing the at least one program instruction.
The terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying a number of the indicated technical features. Thus, a defined feature of "first", "second", may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.