JP2022154788A - Photovoltaic power generation system - Google Patents

Abstract

To provide a photovoltaic power generation system including a solar panel whose failure is easy to find.SOLUTION: A photovoltaic power generation system comprises: a string 21 including a plurality of solar panels 22 connected in series; a charging/discharging unit 31 connected in parallel with at least one of the plurality of solar panels 22; a first power conversion unit 41 that is connected between the charging/discharging unit 31 and the solar panel 22 and is used for charging/discharging of the charging/discharging unit 31; a second power conversion unit 51 for conversing DC power output from the string 21 to AC power; a measurement unit 42 for measuring output characteristics of the solar panels 22; a storage unit 43 for storing previously acquired output characteristics of the solar panels 22; and a determination unit 44 that on the basis of the stored output characteristics and the measured output characteristics, determines presence/absence of failures of the solar panels 22. The determination based on the stored output characteristics and the measured output characteristics makes it easy to find failures of the solar panels 22.SELECTED DRAWING: Figure 1

Description

The present invention relates to photovoltaic power generation systems.

In recent years, power generation systems using renewable energy, such as photovoltaic power generation systems, have attracted attention. A photovoltaic power generation system has a solar panel that converts sunlight (also referred to as solar radiation) into electric power. Therefore, the power output of the photovoltaic power generation system is greatly affected by the weather, specifically, by changes in the amount of solar radiation, and there has been the problem that it is difficult to stably supply power.

In order to solve the above-described problem, a technique has been proposed in which a power storage unit capable of charging and discharging electric power is provided in a photovoltaic power generation system (see Patent Document 1, for example). This photovoltaic power generation system charges the power storage unit with surplus power when the power output of the photovoltaic panel is greater than the required value. On the other hand, when the power output of the solar panel is smaller than the required value, the shortfall is compensated by discharging from the power storage unit.

JP 2008-048544 A

However, the photovoltaic power generation system described in Patent Literature 1 above has a problem that it is difficult to discover a failure of the photovoltaic panel. Specifically, even if the power generation output of the solar panel becomes small due to a failure or the like, the power storage unit is discharged. Therefore, when looking at each photovoltaic power generation system, problems such as a decrease in supplied power do not occur, making it difficult to notice failures. When all the electric power charged in the power storage unit is discharged, troubles such as a decrease in supplied electric power occur even in the unit of the photovoltaic power generation system, and the failure is noticed, but it takes too much time to notice the failure.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a photovoltaic power generation system in which failure of a photovoltaic panel can be easily discovered.

In order to achieve the above object, the present invention provides the following means.
The solar power generation system of the present invention includes a string in which a plurality of solar panels are connected in series, a charging/discharging unit connected in parallel to at least one of the plurality of solar panels, the charging/discharging unit and the A first power conversion unit connected between solar panels and used for charging and discharging the charging/discharging unit, a second power conversion unit converting DC power output from the string into AC power, and the sunlight A measurement unit that measures the output characteristics of the panel, a storage unit that stores the previously acquired output characteristics of the solar panel, and the solar panel based on the stored output characteristics and the measured output characteristics. and a determination unit for determining the presence or absence of a failure.

According to the photovoltaic power generation system of the present invention, it is possible to determine whether or not there is a fault in the photovoltaic panel based on the stored output characteristics and the measured output characteristics. For example, if the measured output characteristics differ from the stored output characteristics beyond a predetermined range, it is determined that the solar panel has failed. Further, when the measured output characteristics fall within a predetermined range from the stored output characteristics, it is determined that there is no failure in the solar panel.

In the above invention, it is preferable that the measurement section, the storage section, and the determination section are provided in the first power conversion section.
By thus providing the measurement unit, the storage unit, and the determination unit in the first power conversion unit, it is possible to determine whether or not the solar panel has failed in the first power conversion unit.

In the above invention, it is preferable that the output characteristic is an output IV characteristic that is a relationship between an output current and an output voltage in the solar panel.
By using the output IV characteristic to determine the presence or absence of a failure in the solar panel in this way, the presence or absence of a failure in the solar panel can be compared with the determination based on the output current alone or the output voltage alone. is easy to determine.

In the above invention, the first power conversion unit divides the output power of the solar panel to which it is connected and the output power of the plurality of solar panels including the other solar panels to which it is not connected. It is preferable to control charging and discharging of the charge/discharge unit based on the average value.

In the above invention, the first power conversion unit controls discharging from the charging/discharging unit when the output power of the solar panel to which the first power conversion unit is connected is smaller than the average value. It is preferable to perform control to charge the charging/discharging unit when the output power of the solar panel obtained is larger than the average value.

Electric power supplied from the solar power generation system by controlling the charging and discharging of the charging/discharging unit based on the output power of the solar panels connected in this way and the average value of the output power of multiple solar panels. It becomes easier to plan the leveling of

According to the photovoltaic power generation system of the present invention, based on the stored output characteristics and the measured output characteristics, there is an effect that it becomes easier to discover failures in the photovoltaic panels.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram explaining the structure of the photovoltaic power generation system which concerns on one Embodiment of this invention. FIG. 2 is a schematic diagram illustrating the configuration of a first power conversion unit in FIG. 1; It is a schematic diagram explaining control of the 1st power converter part at the time of normal. It is a schematic diagram explaining control of the 1st power conversion part at the time of the electric power generation amount fall.

A photovoltaic power generation system according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. The photovoltaic power generation system 10 of this embodiment enables stable supply of electric power to the load facility 60 and facilitates failure detection. In this embodiment, the photovoltaic power generation system 10 is applied to supply power to the load facility 60 , but power may be supplied to the system instead of the load facility 60 .

As shown in FIG. 1, the solar power generation system 10 includes a string 21 in which a plurality of solar panels 22 are connected in series, a charging/discharging unit 31 connected in parallel to the solar panels 22, and a charging/discharging unit 31 and the solar panel 22, and a second power conversion unit 51 that converts the DC power output from the string 21 into AC power.

A string 21 is formed by connecting a plurality of solar panels 22 in series. FIG. 1 shows an example in which the number of solar panels 22 connected in series is three, but the number of solar panels 22 connected may be more or less than three. . Moreover, the kind and scale of the solar panel 22 are not limited.

The charge/discharge unit 31 is a chargeable/dischargeable device connected in parallel to the solar panel 22 . In the present embodiment, the charge/discharge unit 31 is described as being a secondary battery, but other devices such as capacitors may be used as long as they are chargeable/dischargeable devices. Further, in the present embodiment, an example in which the charge/discharge units 31 are connected in parallel to all the solar panels 22 will be described, but the charge/discharge units 31 are connected in parallel only to some of the solar panels 22. may

The first power conversion unit 41 is connected between the charging/discharging unit 31 and the solar panel 22 and used for charging/discharging the charging/discharging unit 31 . In this embodiment, an example in which the first power converter 41 functions as a DC-DC converter will be described. The details of charge/discharge control of the charge/discharge unit 31 in the first power conversion unit 41 will be described later.

The first power conversion unit 41 is provided with a measurement unit 42, a storage unit 43, and a determination unit 44, as shown in FIG. In this embodiment, the first power conversion unit 41 is provided with the measurement unit 42, the storage unit 43, and the determination unit 44. However, the measurement unit 42, the storage unit 43, Also, the determination unit 44 may be provided in a device other than the first power conversion unit 41 .

The measurement unit 42 measures output characteristics of the solar panel 22 to which the first power conversion unit 41 is connected. In this embodiment, an example in which the output characteristic is the output IV characteristic that is the relationship between the output current I and the output voltage V in the solar panel 22 will be described.

The storage unit 43 stores the output characteristics of the solar panel 22 to which the first power conversion unit 41 is connected, which are acquired in advance. In the present embodiment, an example will be described in which the stored output characteristics are the output characteristics obtained when the solar panel 22 is shipped.

The determination unit 44 determines whether or not the solar panel 22 is faulty based on the output characteristics stored in the storage unit 43 and the output characteristics measured by the measurement unit 42 . The details of the determination of the presence/absence of failure will be described later.

The second power converter 51 converts the DC power output from the multiple strings 21 into AC power. In this embodiment, an example in which the second power converter 51 is a DC-AC converter will be described.

Next, details of control in the photovoltaic power generation system 10 configured as described above will be described with reference to FIGS. 3 and 4. FIG. First, charge/discharge control of the charge/discharge unit 31 by the first power conversion unit 41 will be described.

First, when the amount of power generated by the solar panel 22 is within a preset range compared with the average value of the power generated by the other solar panels 22 (also referred to as “normal time”). ), and as shown in FIG. Note that the first power conversion unit 41 acquires the values of the generated power of the other first power conversion units 41 and the solar panel 22 by means of communication or the like, and calculates the average value of the generated power of the other solar panels 22. Calculated.

FIG. 3 shows an example in which the voltage at the solar panel 22 closest to the second power converter 51 is V ₁ , the voltage at the center solar panel 22 is V ₂ , and the voltage at the farthest solar panel 22 is V ₃ . showing. Also, an example is shown in which the current output from the string 21 including these three solar panels 22 toward the second power conversion unit 51 is _I0 .

When the power generated by the central solar panel 22 decreases (the voltage decreases from V ₂ to V ₂ ') compared to the average value of the power generated by the other solar panels 22 (also referred to as "when power generation decreases" ), the first power conversion unit 41 connected to the central solar panel 22 discharges power (current I ₀₂ ) from the charging/discharging unit 31 to which it is connected, as shown in FIG. control.

Here, the value of the power (current I ₀₂ ) discharged from the charging/discharging unit 31 is the sum of the power generated by the center solar panel 22 and the power discharged from the charging/discharging unit 31, is controlled to be equal to the average value of the generated power of

Further, when the power generated by the central solar panel 22 increases from a predetermined value, the first power conversion unit 41 connected to the central solar panel 22 charges the charging/discharging unit 31 to which it is connected. to control.

Here, the value of the power charged to the charge/discharge unit 31 is the value obtained by subtracting the power charged to the charge/discharge unit 31 from the power generated by the center solar panel 22, which is the power generated by the other solar panels 22. is controlled to be equal to the average value of

Next, failure determination of the solar panel 22 in the solar power generation system 10 configured as described above will be described.
The measurement unit 42 of the first power conversion unit 41 measures output characteristics of the solar panel 22 to which it is connected. The determination unit 44 performs a process of calling the output characteristics stored in the storage unit 43 and comparing the called output characteristics with the output characteristics measured by the measurement unit 42 .

As a result of the comparison, if there is a deviation of a predetermined threshold value or more between the called output characteristics and the output characteristics measured by the measurement unit 42, the determination unit 44 detects the solar panel 22 connected to itself. is determined to be faulty. If the difference is less than a predetermined threshold, the determination unit 44 determines that the solar panel 22 connected to itself has no failure.

According to the photovoltaic power generation system 10 configured as described above, it is possible to determine whether or not the photovoltaic panel 22 has failed, based on the stored output characteristics and the measured output characteristics. For example, if the measured output characteristics differ from the stored output characteristics by more than a predetermined position, it is determined that the solar panel 22 has failed. Further, when the measured output characteristics fall within a predetermined threshold from the stored output characteristics, it is determined that the solar panel 22 is not malfunctioning.

By providing the measurement unit 42 , the storage unit 43 , and the determination unit 44 in the first power conversion unit 41 , it is possible to determine whether or not the solar panel 22 is faulty in the first power conversion unit 41 .

By determining the presence or absence of failure of the solar panel 22 using the output IV characteristic, the presence or absence of failure of the solar panel 22 can be determined as compared with the case of determining only by the output current or the case of determining only by the output voltage. Easy to judge.

The power supplied from the photovoltaic power generation system 10 is leveled by controlling the charging/discharging of the charging/discharging unit 31 based on the output power of the solar panel 22 and the average value of the output power of the other solar panels 22. It becomes easier to plan for conversion.

DESCRIPTION OF SYMBOLS 10... Photovoltaic power generation system 21... String 31... Charge/discharge part 41... First power conversion part 51... Second power conversion part 42... Measurement part 43... Storage part 44... Judgment part

Claims (5)

a string in which a plurality of solar panels are connected in series;
a charging/discharging unit connected in parallel to at least one of the plurality of solar panels;
a first power conversion unit connected between the charging/discharging unit and the solar panel and used for charging/discharging the charging/discharging unit;
a second power conversion unit that converts the DC power output from the string into AC power;
a measurement unit that measures output characteristics of the solar panel;
a storage unit that stores previously acquired output characteristics of the solar panel;
a determination unit that determines whether or not the solar panel has failed based on the stored output characteristics and the measured output characteristics;
A photovoltaic power generation system characterized by being provided with. 2. The photovoltaic power generation system according to claim 1, wherein the measurement section, the storage section, and the determination section are provided in the first power conversion section. 3. The solar power generation system according to claim 1, wherein the output characteristic is an output IV characteristic that is a relationship between an output current and an output voltage in the solar panel. The first power conversion unit includes an output power of the solar panel to which it is connected, an average output power of a plurality of solar panels including other solar panels to which it is not connected, and 4. The photovoltaic power generation system according to any one of claims 1 to 3, wherein the charging and discharging of the charging/discharging unit is controlled based on. The first power conversion unit controls discharging from the charging/discharging unit when the output power of the solar panel to which the first power conversion unit is connected is smaller than the average value. 5. The photovoltaic power generation system according to claim 4, wherein when the output power of the optical panel is greater than the average value, control is performed to charge the charge/discharge unit.

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