JP2015095146A - Photovoltaic power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photovoltaic power generation system capable of achieving efficient land use.SOLUTION: A photovoltaic power generation system includes: a storage unit 61 storing therein shadow information indicating whether each solar battery module 1 is shadowed while making the shadow information correspond to date information that is information on a date or time; and a control unit 64 acquiring current date information from a clock section 62, reading the shadow information from the storage unit 61 on the basis of the date information, and switching a state between a state in which each solar battery module 1 is included in serial connection of each solar battery string 5 (first state in which switches 2 connect each connection line 3 to the solar battery modules 2) and a state in which each solar battery module 2 is disconnected from the serial connection of each solar battery string 5 (second state in which the switches 2 connect teach connection line 3 to bypass lines 4). It is possible to achieve efficient land use since the solar battery modules 1 can be arranged even in an often shadowed area.

Description

  The present invention relates to a photovoltaic power generation system.

  In recent years, large-scale solar power generation systems called mega solar have been built in various places. The solar power generation system converts DC power output from a solar cell array in which a plurality of solar cell strings are connected in parallel into AC power using a power conditioner, and supplies the AC power to a load or a power system. The solar cell string is configured by connecting a plurality of solar cell modules in series (see, for example, Patent Document 1).

  FIG. 5 is a diagram for explaining a conventional photovoltaic power generation system, and shows a solar cell array. A plurality of solar cell modules 1 are connected in series to constitute a solar cell string 5, and a plurality of solar cell strings 5 are connected in parallel to constitute a solar cell array.

  As shown in FIG. 5A, when a part of the solar cell module 1 is shaded, the solar cell module 1 acts like a resistor with a reduced power generation amount. Therefore, the entire solar cell string 5 in which the solar cell modules 1 are connected in series is affected. Therefore, when it is known in advance that a shadow can be formed, the solar cell module 1 is arranged avoiding the position where the shadow is applied. FIG. 5B shows a case where the solar cell module 1 is arranged avoiding the position where the shadow S is formed.

  When constructing a solar power generation system, an area in which the shadow of the building can be shadowed (hereinafter referred to as “sunlight-affected area”) is determined in advance so that the solar cell module 1 is not disposed at the position where the shadow is applied. Do the design.

  FIG. 6A is a diagram for explaining the shade-affected area, and shows the shade-affected area C of the building B on the site A. FIG. The upper side of the figure is the north side. Since the sun is the lowest on the day of the winter solstice, the shadow of building B reaches the widest area. The shadow influence area C is set based on the shadow of the winter solstice day. A shadow S1 indicated by a broken line is a shadow of the building B in the morning on the winter solstice day. Similarly, shadows S2 and S3 indicated by broken lines indicate noon and evening shadows, respectively. The shade-affected area C is set as an area where a shadow of a predetermined time (for example, 1 hour) or more is applied during the power generation possible time (for example, from 8:00 to 16:00) on the winter solstice day. Each solar cell module 1 is arranged in an area other than the shade-affected area C in the site A.

JP 2012-169531 A

  As shown in FIG. 6 (a), the solar cell module 1 is not disposed in the area affected by the shadow S3 in the shade affected area C, although it is hardly shaded in the morning. Although it is possible to generate power depending on the time of day, power cannot be generated because the solar cell module 1 is not arranged. Site A cannot be used effectively.

  FIG. 6B shows the shadow effect area C ′ on the summer solstice day. A shadow S1 'indicated by a broken line is a shadow of the building B in the morning on the summer solstice day. Similarly, shadows S2 'and S3' indicated by broken lines indicate noon and evening shadows, respectively. The shadow influence area C ′ on the day of the summer solstice is a narrower area than the shadow influence area C (on the day of the winter solstice). As shown in FIG. 6 (b), the solar cell module 1 is not disposed in the shadow influence area C other than the shadow influence area C 'except for shadows other than before and after the winter solstice. Although it is possible to generate power depending on the season, it cannot be generated because the solar cell module 1 is not arranged. Site A cannot be used effectively.

  The present invention has been conceived under the circumstances described above, and an object of the present invention is to provide a solar power generation system that can efficiently use land.

  In order to solve the above problems, the present invention takes the following technical means.

  The solar power generation system provided by the first aspect of the present invention is a solar power generation system including a solar cell string in which a plurality of solar cell modules are connected in series, and corresponds to date and time information that is date or time information. In addition, storage means for storing shadow information indicating whether or not each solar cell module is shaded, date / time information acquisition means for acquiring current date / time information, and date / time information acquired by the date / time information acquisition means A reading means for reading out shadow information from the storage means, and a state in which the solar cell modules are included in a series connection of the solar cell strings based on the shadow information read by the reading means; and It is characterized by comprising switching means for switching the state disconnected from the series connection of the solar cell strings.

  In a preferred embodiment of the present invention, the solar cell string includes the solar cell module, detour wiring for detouring so as not to connect the solar cell module, and the solar cell module as an adjacent solar cell module. A connection wiring for connection; a switch that is switched to a first state in which the connection wiring and the solar cell module are connected; and a second state in which the connection wiring and the bypass wiring are connected. The switching means sets the switch in the first state, thereby setting the solar cell module in a state of being included in the series connection of the solar cell strings, and setting the switch in the second state. The solar cell module is separated from the series connection of the solar cell strings.

  In a preferred embodiment of the present invention, the photovoltaic power generation system includes a voltage sensor that measures a voltage between terminals of the solar cell module, and a voltage value measured by the voltage sensor is less than a predetermined voltage value. The solar cell module further includes separation means for separating each solar cell module from the solar cell string.

  In a preferred embodiment of the present invention, the solar power generation system includes a solar radiation intensity sensor that measures the solar radiation intensity around the solar cell module, and the solar radiation intensity measured by the solar radiation intensity sensor is less than a predetermined value. In addition, the solar cell module further includes a second disconnecting means for separating each solar cell module from the solar cell string.

  In preferable embodiment of this invention, the said solar cell module is a compound type | system | group.

  According to the present invention, the shadow information corresponding to the current date and time information is read, and the connection state of each solar cell module is switched according to the shadow information. Since the shadowed solar cell module is disconnected from the series connection and does not affect the solar cell string, the solar cell module can be arranged in a region where the shadow may be applied. As a result, the land can be utilized efficiently.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a figure for demonstrating the solar energy power generation system which concerns on 1st Embodiment. It is a flowchart for demonstrating the switching process which a control part performs. It is a figure for demonstrating a mode that the connection state of a solar cell module changes with time. It is a figure for demonstrating the solar energy power generation system which concerns on 2nd Embodiment. It is a figure for demonstrating the conventional solar power generation system. It is a figure for demonstrating a shade influence area | region.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a diagram for explaining the photovoltaic power generation system according to the first embodiment. The solar power generation system includes a plurality of parallel connected solar cell strings 5 and a switching control device 6. In addition, in the same figure, description of the power conditioner etc. to which the some solar cell string 5 connected in parallel is connected is abbreviate | omitted. The DC power generated by each solar cell string 5 is converted into AC power by a power conditioner and supplied to a load or a power system.

  The solar cell string 5 includes a solar cell module 1, a switch 2, a connection wiring 3, and a bypass wiring 4. In FIG. 1, detailed display is performed in the uppermost solar cell string 51, but simplified display is performed in the lower two solar cell strings 5.

  The solar cell module 1 generates power by converting sunlight into electric energy. The solar cell module 1 is configured by connecting a plurality of solar cells not shown in series and parallel. In this embodiment, crystalline silicon solar cells are used. In addition, the kind of photovoltaic cell is not limited. The solar cell module 1 is also arranged in a shadowed area depending on the date and time zone.

  The switch 2 switches between a state where the solar cell module 1 is included in the series connection of the solar cell strings 5 and a state where the solar cell module 1 is disconnected from the series connection of the solar cell strings 5. Two switches 2 are provided in each solar cell module 1. Each switch 2 is connected to the connection wiring 3 and the output terminal of the solar cell module 1 according to a signal input from the switching control device 6 (first state), the connection wiring 3 and the bypass wiring 4. To the connected state (second state). When the switch 2 is in the first state, the solar cell module 1 is included in a series connection of the solar cell strings 5 (see the solar cell module 12 in FIG. 1). On the other hand, when the switch 2 is in the second state, the solar cell module 1 is disconnected from the series connection of the solar cell strings 5 (see the solar cell module 11 in FIG. 1). In the solar cell string 51 of FIG. 1, the solar cell modules 12 are connected in series, but the solar cell module 11 is disconnected.

  In addition, even if the solar cell module 1 is disconnected from the series connection of the solar cell strings 5, the number of the solar cell modules 1 included in each solar cell string 5 is appropriately set so that the solar cell string 5 can maintain a desired voltage. Need to design. Further, for the solar cell module 1 in which the shadowing time is less than the predetermined time, the corresponding switch 2 and bypass wiring 4 are not provided, and these solar cell modules 1 are similar to the conventional ones. Are connected in series by connection wiring 3 (see solar cell module 13 in FIG. 1). That is, the corresponding switch 2 and detour wiring 4 are only applied to the solar cell module 1 in which the shadowing time is equal to or longer than the predetermined time, that is, the solar cell module 1 arranged in the shade-affected area C (see FIG. 6). Is provided.

  The switching control device 6 controls switching of each switch 2. The switching control device 6 includes a storage unit 61, a clock unit 62, a communication unit 63, and a control unit 64.

  The memory | storage part 61 memorize | stores the information (shadow information) which shows which solar cell module 1 is shaded with a date and time. The shadow information is information (for example, a serial number assigned to each solar cell module 1) of the solar cell module 1 that is shaded and associated with a date and time (for example, every 5 minutes). The storage unit 61 stores in advance shadow information of a time zone in which power generation for one year is possible (the sun comes out and reaches a predetermined solar radiation intensity).

  The clock unit 62 has a clock function and a calendar function, and outputs the current date and time to the control unit 64. The communication unit 63 communicates with each switch 2 and outputs a signal according to an instruction from the control unit 64 to each switch 2. The communication method may be wired communication via a cable or wireless communication.

  The control unit 64 controls the switching control device 6 and performs switching processing for switching each switch 2. The control unit 64 reads the shadow information stored in the storage unit 61 according to the current date and time input from the clock unit 62, and causes the communication unit 63 to output a signal according to the shadow information. The control unit 64 causes the switch 2 for switching the solar cell module 1 to be shaded to output a detour signal that is a high level signal. The switch 2 to which the detour signal is input is in the second state (a state in which the connection wiring 3 and the detour wiring 4 are connected), and the solar cell module 1 is disconnected from the series connection of the solar cell strings 5. Moreover, the control part 64 outputs a low level signal with respect to the switch 2 for switching the solar cell module 1 which does not have a shadow. The switch 2 to which the low level signal is input is in the first state (a state in which the connection wiring 3 and the output terminal of the solar cell module 1 are connected), and the solar cell module 1 is included in the series connection of the solar cell strings 5. It becomes a state.

  FIG. 2 is a flowchart for explaining the switching process performed by the control unit 64. The switching process is started when the switching control device 6 is activated.

  First, the control unit 64 acquires the current date and time from the clock unit 62 (S1). And the shadow information according to the acquired date is read from the memory | storage part 61 (S2). In the present embodiment, the shadow information is read at every time (for example, every 5 minutes) with which the shadow information is associated. The control unit 64 determines whether or not there is a solar cell module 1 that is shaded (needs a detour) from the read shadow information (S3), and if so (S3: YES), the solar cell that is shaded A bypass signal (high level signal) is output from the communication unit 63 to the switch 2 for switching the module 1 (S4), and the process returns to step S1. When there is no instruction from the control unit 64, the communication unit 63 outputs a low level signal to each switch 2. When there is no shadowed solar cell module 1 (S3: NO), the detour signal (high level signal) is not output, the low level signal is output to all the switches 2, and the process returns to step S1. Thereafter, steps S1 to S4 are repeated. That is, normally, each switch 2 receives the low level signal and enters the first state, and the solar cell module 1 is included in the series connection of the solar cell strings 5, but the shadowed sun A switch 2 for switching the battery module 1 receives a detour signal (high level signal) and enters a second state, and the shadowed solar cell module 1 is disconnected from the series connection of the solar cell strings 5. It becomes a state. Note that the flowchart of the switching process is not limited to that shown in FIG.

  FIG. 3 is a diagram for explaining how the connection state of the solar cell module 1 changes with time. In the figure, only the periphery of the solar cell modules 11 and 12 of the solar cell string 51 is described, and other descriptions are omitted.

  FIG. 3A shows a state in which the solar cell modules 11 and 12 do not have a shadow S. In this time zone, the switches 21 and 22 receive a low level signal and enter a first state (a state in which the connection wiring 3 and the output terminal of the solar cell module 11 (12) are connected). The modules 11 and 12 are included in the series connection of the solar cell strings 51. In FIG. 3A, the shadow S has progressed from left to right, but the shadow S has not yet been applied to the solar cell module 11.

  Immediately after the state of FIG. 3A, a detour signal (high level signal) is input to the switch 21 based on the shadow information stored in the storage unit 61, and the switch 21 is changed from the first state to the second state. (A state in which the connection wiring 3 and the bypass wiring 4 are connected). Thereafter, the input of the detour signal (high level signal) is continued and the second state is continued. On the other hand, the bypass signal (high level signal) is not input to the switch 22, the input of the low level signal continues, and the switch 22 continues the first state. At this time, the solar cell module 12 is included in the series connection of the solar cell strings 51, but the solar cell module 11 is disconnected from the series connection of the solar cell strings 51 (see FIG. 3B). Therefore, the solar cell module 11 that is shaded S does not affect the solar cell string 51.

  After a while from the state of FIG. 3B, a detour signal (high level signal) is input to the switch 22 based on the shadow information stored in the storage unit 61, and the switch 22 is switched from the first state to the second state. Switch to the state. Thereafter, the input of the detour signal (high level signal) is continued and the second state is continued. On the other hand, the detour signal (high level signal) continues to be input to the switch 21 and the switch 21 continues to be in the second state. At this time, the solar cell modules 11 and 12 are disconnected from the series connection of the solar cell strings 51 (see FIG. 3C). Therefore, the solar cell modules 11 and 12 that are shaded S do not affect the solar cell string 51.

  After a while in the state of FIG. 3C, the input of the detour signal (high level signal) to the switch 21 is stopped based on the shadow information stored in the storage unit 61 (the low level signal is input). ), The switch 21 is switched from the second state to the first state. Thereafter, the input of the low level signal is continued and the first state is continued. On the other hand, the input of the detour signal (high level signal) to the switch 22 is continued, and the switch 22 continues the second state. At this time, the solar cell module 11 is included in the series connection of the solar cell strings 51, but the solar cell module 12 is disconnected from the series connection of the solar cell strings 51 (see FIG. 3D). Therefore, the solar cell module 12 with shadow S does not affect the solar cell string 51.

  After a while in the state of FIG. 3D, the input of the bypass signal (high level signal) to the switch 22 is also stopped based on the shadow information stored in the storage unit 61 (the low level signal is input). ), The switch 22 is switched from the second state to the first state. Thereafter, the input of the low level signal is continued and the first state is continued. On the other hand, the input of the low level signal to the switch 21 is also continued, and the switch 21 continues in the first state. At this time, similarly to the state of FIG. 3A, the solar cell modules 11 and 12 are included in the series connection of the solar cell strings 51.

  In the present embodiment, the switching control device 6 switches the solar cell module 1 to which the shadow is applied from the series connection of the solar cell strings 51 based on the shadow information stored in the storage unit 61. Therefore, even if the solar cell module 1 is shaded, it does not affect the solar cell string 51. Therefore, the solar cell module 1 can be arranged in a region where the shadow may be cast. As a result, the land can be utilized efficiently.

  In the present embodiment, the case where the storage unit 61 stores shadow information in association with a date and time (for example, every 5 minutes) is described, but the present invention is not limited to this. Since the shadow position at the same time does not change much in one day, it may be stored every week or every month. Further, it may be stored every 10 minutes or every hour instead of every 5 minutes. Since the amount of information to be stored in the storage unit 61 increases as the period is shortened, it takes time and effort to acquire and store shadow information, and a large amount of storage area is required, but finer control can be performed. . On the other hand, the longer the period, the rougher the control, but the trouble of acquiring and storing shadow information is simplified and the storage area is reduced. Further, the shadow information may be stored in association with only the time without using the date information, or the shadow information may be stored in association with only the date without using the time information.

  In this embodiment, although the case where the switch 2 was provided for every solar cell module 1 was demonstrated, it is not restricted to this. A switch 2 may be provided for each of the plurality of solar cell modules 1. In this case, the number of switches 2 and bypass wirings 4 can be reduced.

  In the first embodiment, when a shadow can be predicted in advance, the shadowed solar cell module 1 is disconnected from the series connection of the solar cell strings 5 so as not to affect the solar cell string 5. It is. Therefore, when an unpredictable shadow is applied to the solar cell module 1, the solar cell string 5 may be affected. For example, a shadow caused by a cloud or a dust or dirt adhering to the light receiving surface of the solar cell module 1 cannot be predicted. These shadows may also affect the solar cell string 5. A case where the influence of an unpredictable shadow is also considered will be described below as a second embodiment.

  FIG. 4A is a diagram for explaining the photovoltaic power generation system according to the second embodiment, and only the periphery of one solar cell module 1 (corresponding to the solar cell modules 11 and 12 in FIG. 1) is described. It is a thing. In Fig.4 (a), the same code | symbol is attached | subjected to the element which is the same as that of the solar energy power generation system (refer FIG. 1) which concerns on 1st Embodiment (refer FIG. 1).

  In the photovoltaic power generation system according to the second embodiment, the switches 2 and the bypass wirings 4 corresponding to all the solar cell modules 1 are provided, and for each solar cell module 1, the voltage sensor 7 and It differs from the photovoltaic power generation system according to the first embodiment in that the separation portion 8 is provided.

  The voltage sensor 7 measures a voltage between terminals of the solar cell module 1. The voltage sensor 7 outputs the measured voltage value to the separation unit 8. The separation unit 8 controls switching of the switch 2. When the voltage between the terminals of the solar cell module 1 becomes less than a predetermined voltage value, the disconnecting unit 8 determines that the solar cell module 1 is shaded or the solar cell module 1 has failed, and the solar cell The module 1 is disconnected from the series connection of the solar cell strings 5. Specifically, the disconnecting unit 8 compares the voltage value input from the voltage sensor 7 with a predetermined voltage value, and outputs a bypass signal (high level signal) to the switch 2 when the voltage value is less than the predetermined voltage value. Output. The switch 2 to which the detour signal is input is in the second state (a state in which the connection wiring 3 and the detour wiring 4 are connected), and the solar cell module 1 is disconnected from the series connection of the solar cell strings 5.

  In 2nd Embodiment, when the voltage between terminals of the solar cell module 1 becomes less than a predetermined voltage value, the said solar cell module 1 is made into the state disconnected from the serial connection of the solar cell string 5. FIG. Therefore, even when an unpredictable shadow is applied to the solar cell module 1 or when the solar cell module 1 breaks down, the solar cell module 1 can be prevented from affecting the solar cell string 5.

  Moreover, it replaces with the voltage sensor 7, the solar radiation intensity sensor 7 'which measures the solar radiation intensity | strength to the solar cell module 1 is provided, and the solar radiation intensity input from the solar radiation intensity sensor 7' by the separation part 8 is less than predetermined value Alternatively, a bypass signal (high level signal) may be output (see FIG. 4B). Also in this case, it is possible to prevent the solar cell module 1 from affecting the solar cell string 5 when an unpredictable shadow is applied to the solar cell module 1.

  If the solar cell module 1 is made of a compound system such as CIS or CIGS instead of crystalline silicon, power can be generated even if a part of the solar cell module 1 is shaded. The effect of this can be mitigated.

  The solar power generation system according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the photovoltaic power generation system according to the present invention can be varied in design in various ways.

DESCRIPTION OF SYMBOLS 1,11,12 Solar cell module 2,21,22 Switch 3 Connection wiring 4 Detour wiring 5 Solar cell string 6 Switching control device 61 Memory | storage part 62 Clock part 63 Communication part 64 Control part (Date information acquisition means, reading means, switching) means)
7 voltage sensor 7 'solar radiation intensity sensor 8 separation part (separation means, second separation means)
S, S1, S2, S3, S1 ', S2', S3 'Shadow A Site B Building C, C'

Claims (5)

A solar power generation system including a solar cell string in which a plurality of solar cell modules are connected in series,
Storage means for storing shadow information indicating whether or not each solar cell module is shaded in association with date and time information which is date or time information;
Date and time information acquisition means for acquiring current date and time information;
Based on the date information acquired by the date information acquisition means, reading means for reading out shadow information from the storage means,
Switching means for switching between a state in which each of the solar cell modules is included in the series connection of the solar cell strings and a state of being disconnected from the series connection of the solar cell strings based on the shadow information read out by the reading unit. When,
A solar power generation system characterized by comprising: The solar cell string is
The solar cell module;
Detour wiring for detouring so as not to connect the solar cell module;
Connection wiring for connecting the solar cell module to an adjacent solar cell module;
A switch that is switched between a first state in which the connection wiring and the solar cell module are connected, and a second state in which the connection wiring and the bypass wiring are connected;
With
The switching means is
By setting the switch to the first state, the solar cell module is included in a series connection of the solar cell strings,
By setting the switch to the second state, the solar cell module is disconnected from the series connection of the solar cell strings.
The photovoltaic power generation system according to claim 1. A voltage sensor for measuring a voltage between terminals of the solar cell module;
When the voltage value measured by the voltage sensor is less than a predetermined voltage value, the separation means for making each of the solar cell modules separated from the solar cell string,
Further equipped with,
The photovoltaic power generation system according to claim 1 or 2. A solar radiation intensity sensor for measuring the solar radiation intensity around the solar cell module;
When the solar radiation intensity measured by the solar radiation intensity sensor is less than a predetermined value, the second separation means for making each of the solar cell modules separated from the solar cell string;
Further equipped with,
The photovoltaic power generation system according to any one of claims 1 to 3. The solar cell module is a compound system,
The photovoltaic power generation system according to any one of claims 1 to 4.

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