KR101029510B1 - Method for determining washing time of photovoltaic sensor module of photovoltaic power generation system - Google Patents

Abstract

PURPOSE: A method for determining washing time of the photovoltaic sensor module of a photovoltaic power generation system are provided to exactly determine a time of cleaning a plurality of solar sensor modules with low costs by sensing voltage and current which are generated from a pollution index unit. CONSTITUTION: A plurality of solar sensor modules(101) changes sunlight into electrical energy. A pollution index unit(102) is installed under same external environment as the plural solar sensor modules. The pollution index unit indicates the level of contamination of the plural solar modules. A washing determination unit(103) measures the amount of foreign material which is formed on the pollution index unit. The washing determination unit determines whether the plural solar sensor modules is cleaned or not based on a measurement result.

Description

Method of Determining Cleaning Time of Photovoltaic Sensor Module of Photovoltaic System {METHOD FOR DETERMINING WASHING TIME OF PHOTOVOLTAIC SENSOR MODULE OF PHOTOVOLTAIC POWER GENERATION SYSTEM}

The present invention relates to a photovoltaic power generation system, and in particular, the cleaning timing of the photovoltaic power generation system of the photovoltaic power generation system that can accurately know the timing of cleaning the photovoltaic sensor module by accurately measuring the amount of dust accumulated in the photovoltaic sensor module It is about how to judge.

Since the solar sensor module is installed externally, foreign substances such as dust are easily attached to the surface of the solar cell. If dust is continuously deposited on the surface of the solar cell, the dust blocks the sun, and thus the solar sensor module cannot function normally. Therefore, the surface of the solar cell should be periodically cleaned. These cleaning operations are time consuming and expensive and should be performed at the right time. However, in the related art, it is difficult to accurately determine the amount of dust attached to the surface of the solar cell, and thus, it is difficult to accurately determine the cleaning time.

The present invention has been made in order to solve the above-described problems, install a pollution indicator that can grasp the pollution degree of the plurality of solar sensor modules, and measure the voltage and current generated from this pollution indicator in real time to the rest of the By indirectly determining the amount of dust attached to the optical sensor modules to provide a method for determining the cleaning time of the solar sensor module of the photovoltaic system that can accurately determine when to clean the plurality of solar sensor modules at a low cost. The purpose is.

Cleaning time determination method of the solar sensor module of the solar power generation system according to the present invention for achieving the above object, a plurality of solar sensor modules for converting sunlight into electrical energy, and the plurality of solar sensors In the cleaning time determination method of the photovoltaic sensor module of the photovoltaic system including at least one pollution indicator exposed to the same environment as the module, by grouping a plurality of solar cells formed on the incident surface of the pollution indicator, A step of defining a plurality of solar cells arranged in a direction perpendicular to the direction of gravity as a cell group; And a step (B) of measuring a cell group current and a cell group voltage of each cell group and determining whether the solar module sensors are cleaned based on at least one of the measured cell group current and the cell group voltages. It is characterized by.

Step B-1 includes measuring cell group currents generated by the solar cells included in each cell group when no foreign matter is formed in the solar cells of the pollution indicator unit; Setting the measured cell group currents as reference cell group currents, respectively; The pollution indicator is installed externally, and the cell group currents generated by the solar cells included in each cell group are measured at predetermined times, and each of the measured cell group currents and the first predetermined threshold are set at a predetermined time. A step B-3 comparing each time; Step B-4 of selecting one cell group current having the smallest value among the cell group currents having a value smaller than the first threshold; A step B-5 of calculating an average decrease amount of the cell group current selected in step B-4; Linearly approximating the decrease in the selected cell group current and calculating an expected time for the selected cell group current to reach a second threshold based on the approximated decrease, and notifying the user of the decrease; The second threshold is less than the first threshold; The second threshold value has a value corresponding to n% (n is a natural number less than 100) of the reference cell group current corresponding to the selected cell group current.

Step B-1 includes measuring cell group currents generated by the solar cells included in each cell group when no foreign matter is formed in the solar cells of the pollution indicator unit; Setting the measured cell group currents as reference cell group currents, respectively; The pollution indicator is installed externally, and the cell group currents generated by the solar cells included in each cell group are measured at predetermined times, and each of the measured cell group currents and the first predetermined threshold are set at a predetermined time. A step B-3 comparing each time; Step B-4 of selecting one cell group current having the smallest value among the cell group currents having a value smaller than the first threshold; A step B-5 of calculating an average decrease amount of the cell group current selected in step B-4; Linearly approximating the decrease amount of the selected cell group current and calculating an expected time for the selected cell group current to reach a second threshold based on the approximated decrease amount; B-7 step of measuring the amount of solar radiation applied to the incident surface of the contamination indicator portion; B-8 step of measuring the temperature of the surface of the incident surface of the contamination indicator; B-9 measuring the amount of foreign matter floating around the surface of the incident surface of the contamination indicator; A step B-10 for adjusting the estimated time based on the amount of insolation in step B-7, the temperature in step B-8 and the amount of foreign matter in step B-9; The second threshold is less than the first threshold; The second threshold value has a value corresponding to n% (n is a natural number less than 100) of the reference cell group current corresponding to the selected cell group current.

The amount of insolation, temperature and the amount of foreign matter are divided into m steps (m is a natural number of two or more) according to the value thereof; The step B is to advance the expected time when each step indicating the measured amount of insolation and temperature has a higher value than the step indicating the amount of foreign matter, and any one of the steps indicating the measured insolation and temperature is When it has a lower value than the step indicating the amount of foreign matters is characterized in that to maintain the expected time in the step B-6.

The pollution indicator is characterized in that at least one of the plurality of solar sensor modules.

Each solar sensor module and pollution indicator portion includes an incident surface on which a plurality of solar cells for converting sunlight into electrical energy are formed; The area and the shape of the incident surface of the solar sensor module are the same as the area and the shape of the incident surface of the contamination indicator; The number, type, shape, and size of the solar cells formed in the solar sensor module are the same as the number, type, shape, and size of the solar cells formed in the contamination indicator.

Method for determining the cleaning time of the solar sensor module of the photovoltaic power generation system according to the present invention has the following effects.

In the present invention, by installing a pollution indicator to determine the degree of contamination of the plurality of solar sensor modules, by measuring the voltage and current generated from the pollution indicator in real time to determine the amount of dust attached to the remaining solar sensor modules By knowing indirectly, it is possible to accurately determine when to clean multiple solar sensor modules at low cost.

1 is a view showing a solar system according to a first embodiment of the present invention
2 is a detailed configuration diagram of the pollution indicator of FIG.
3 is a detailed configuration diagram of the cell group current measurement unit
4 is a diagram illustrating a connection relationship between hall sensors and cell groups of FIG. 3;
5 is a detailed configuration diagram of the cell group voltage measurement unit
6 is a diagram illustrating a connection relationship between voltage measuring units and cell groups of FIG. 5.
7 is a view illustrating first to third noise filter units and first to third amplification units provided in the cleaning unit;
8 is a detailed configuration diagram of the solar radiation measuring unit
9 is a view showing another configuration example of the contamination indicator unit
10 is a view showing a solar power system according to a second embodiment of the present invention.
11 is a flowchart illustrating a method for determining a cleaning time of a solar sensor module of a solar power generation system according to a first embodiment of the present invention.
12 is a flowchart illustrating a method for determining a cleaning time of a photovoltaic sensor module of a photovoltaic system according to a second embodiment of the present invention.
FIG. 13 is a view illustrating a method for determining a cleaning time of a solar sensor module according to first and second embodiments of the present invention; FIG.

1 is a view showing a solar system according to a first embodiment of the present invention.

The photovoltaic power generation system according to the first embodiment of the present invention, as shown in FIG. 1, includes a plurality of solar sensor modules 101, a pollution indicator 102, and a cleaning determination unit 103. do.

Solar sensor modules 101 convert sunlight into electrical energy.

The pollution indicator 102 converts sunlight into electrical energy like the solar sensor modules 101, and the pollution indicator 102 is installed in the same external environment as the solar sensor modules 101. . That is, the contamination indicator 102 may have the same configuration and size as the solar sensor modules 101. Such a pollution indicator unit 102 indicates the degree of contamination of the plurality of solar sensor modules 101, one or more of the pollution indicator unit 102 may be installed. This pollution degree means the pollution degree of each solar sensor module 101 to the foreign matter, the foreign matter may be dust. In the present invention, unless otherwise indicated, the foreign matter refers to dust.

The cleaning determination unit 103 measures the amount of foreign matter formed in the pollution indicator unit 102 and determines whether the plurality of solar sensor modules 101 are cleaned based on the measurement result. That is, the cleaning determination unit 103 calculates the amount of foreign matter attached to the pollution indicator unit 102, and whether the solar sensor module 101 needs to be cleaned according to the calculated value. Inform.

2 is a detailed block diagram of the pollution indicator 102 of FIG.

As shown in FIG. 2, the pollution indicator unit 102 includes a plurality of solar cells C converting sunlight into electrical energy. The solar cells C are formed on the incident surface 222 of the contamination indicator 102. Each solar cell (C) may be composed of a solar cell, a storage battery and a power converter. The solar cell is formed by joining a P-type semiconductor and an N-type semiconductor. When solar light is irradiated to the solar cell, holes and electrons are generated by the energy of the solar light. At this time, holes move toward the P-type semiconductor and electrons move toward the N-type semiconductor to generate current. The solar cell may be classified into a single crystal solar cell and a polycrystalline solar cell according to the semiconductor used.

These solar cells C are arranged in a matrix form, as shown in FIG. Here, a plurality of cells arranged in a direction perpendicular to the direction of gravity forms one cell group. As an example, six cell groups CG1 to CG6 are illustrated in FIG. 2, and each cell group includes eight solar cell cells C. Referring to FIG.

A plurality of solar cells included in one cell group are electrically connected in series by one wire (any one of L1 to L5).

On the other hand, each solar sensor module 101 also has the same form as the above-described pollution indicator 102. That is, each solar sensor module 101 also has an incident surface, and a plurality of solar cells for converting sunlight into electrical energy are formed on the incident surface. In this case, the area and the shape of the incident surface of the solar sensor module 101 may be the same as the area and the shape of the incident surface 222 of the contamination indicator 102. In addition, the number, type, shape, and size of the solar cells formed in the solar sensor module 101 are the same as the number, type, shape, and size of the solar cells C formed in the pollution indicator unit 102. can do. Here, the kind of solar cell C means the kind of solar cell formed in this solar cell C. As shown in FIG. That is, as described above, the solar cell may be classified into a single crystal solar cell and a polycrystalline solar cell according to the semiconductor used.

The photovoltaic sensor modules 101 change the angle of the incidence surface in accordance with the movement of the sun so that the incidence surface faces the sun. The pollution indicator 102 is also the same as the photovoltaic sensor modules 101. The angle of the incident surface 222 is controlled. Therefore, the incident surface angles of the solar sensor modules 101 and the pollution indicators 102 are controlled to be the same. That is, the angles of the incident surfaces of the solar sensor modules 101 and the incident surfaces of the pollution indicators 102 are the same in all time zones.

The cleaning determination unit 103 measures the amount of foreign matter formed in the pollution indicator unit 102 based on the cell group current and the cell group voltage generated by the cells included in each cell group, and based on the measured value, It is determined whether the optical sensor modules 101 are cleaned. Here, each of the cell group currents is converted into a voltage value and supplied to the cleaning determination unit 103.

For example, as shown in FIG. 2, the cleaning decision unit 103 may include a first voltage (voltage corresponding to the first cell group current) and a first voltage generated by the cells of the first cell group GC1. Cell group voltage, the second voltage generated by the cells of the second cell group GC2 (voltage corresponding to the second cell group current) and the second cell group voltage, generated by the cells of the third cell group GC3 The third voltage (voltage corresponding to the third cell group current) and the third cell group voltage, the fourth voltage generated by the cells of the fourth cell group CG4 (voltage corresponding to the fourth cell group current), and The fourth cell group voltage, the fifth voltage (voltage corresponding to the fifth cell group current) and the fifth cell group voltage generated by the cells of the fifth cell group GC5 are respectively measured, and the sixth cell group ( Measuring the sixth voltage (voltage corresponding to the sixth cell group current) and the sixth cell group voltage generated by the cells of GC6, respectively, and based on these measured values, Determine whether the solar sensor module 101 of the cleaning.

On the other hand, in order to more accurately determine the amount of foreign matter attached to the photovoltaic sensor modules 101, the pollution indicator 102 is a solar radiation measuring unit 201, temperature measuring unit 202 and foreign matter measuring unit 203 It may be further provided.

The solar radiation measuring unit 201 measures the solar radiation amount applied to the surface of the pollution indicator 102.

The temperature measuring unit 202 measures the temperature of the surface of the contamination indicator 102.

The foreign matter measuring unit 203 measures the amount of foreign matter floating around the surface of the contamination indicator 102. This foreign matter means dust, and the foreign matter measuring unit 203 measures the amount of dust floating in the air on the incident surface 222 of the contamination indicator 102. That is, the foreign matter measuring unit 203 is a device for measuring the transparency of air, which irradiates light into the air using an internal light source, and receives the light passing through the air, based on the amount of light received. The concentration of dust in the air can be measured.

As such, when the pollution indicator 102 further includes the above-described solar radiation measurement unit 201, the temperature measurement unit 202, and the foreign matter measurement unit 203, the above-described cleaning determination unit 103 includes the contamination indicator unit. The sun is based on the measurement result of the amount of the foreign matter formed in the 102, the measurement result from the solar radiation measurement unit 201, the measurement result from the temperature measurement unit 202, and the measurement result from the foreign matter measurement unit 203. It is determined whether the optical sensor modules 101 are cleaned. These measurement results are all expressed in voltage.

The cleaning decision unit 103 basically includes a cell group current measuring unit, a cell group voltage measuring unit, and a data analyzing unit. As described above, the contamination indicator unit 102 measures the solar radiation measuring unit 201 and the temperature. In addition, if the unit 202 and the foreign matter measuring unit 203 is further provided, the cleaning determination unit 103 is a first noise filter unit for removing noise from the measurement value from the solar radiation measuring unit 201, the first noise A first amplifying unit for amplifying the measured value from the filter unit, a second noise filter unit for removing noise from the measured value from the temperature measuring unit 202, a second amplifying unit for amplifying the measured value from the second noise filter unit, And a third noise filter unit for removing noise from the measurement value from the foreign material measuring unit 203, and a third amplifier unit for amplifying the measurement value from the third noise filter unit.

Each component described above will be described in more detail as follows.

The cell group current measuring unit measures the cell group currents of the cell groups and converts the measured cell group currents into voltages. For example, if there are six cell groups, the cell group current measuring unit measures six cell group currents and converts the six cell group currents into six voltages.

The cell group voltage measuring unit measures the cell group voltages of the cell groups. For example, if there are six cell groups, the cell group voltage measuring unit measures six cell group voltages.

The data analyzer converts the voltages measured by the cell group current measuring unit and the cell group voltages measured by the cell group voltage measuring unit into digital data, and analyzes the digital data to clean the plurality of solar sensor modules 101. Determine whether or not.

However, as described above, when the pollution indicator 102 further includes the solar radiation measurement unit 201, the temperature measurement unit 202, and the foreign matter measurement unit 203, the above-described data analyzer measures the cell current measurement unit. The measured voltages, the cell group voltages measured from the cell group voltage output unit, the measured value from the first amplifier, the measured value from the second amplifier, and the measured value from the third amplifier into digital data, and analyze the digital data. It is determined whether the plurality of solar sensor modules 101 are washed.

3 is a detailed configuration diagram of a cell group current measuring unit, and FIG. 4 is a diagram illustrating a connection relationship between hall sensors and cell groups of FIG. 3.

As illustrated in FIGS. 3 and 4, the cell group current measuring unit CGC includes a plurality of current measuring units CC1 to CC6 that measure cell group currents from the cell groups. The cell group currents are converted into voltages and supplied to the data analyzer DA. 3 shows an example in which six current measuring units CC1 to CC6 are provided.

Each current measuring unit CC1 to CC6 includes a hall sensor HS, a load resistor R, a noise filter unit NF, and an amplifier unit AP as shown in FIGS. 3 and 4.

The load resistor R is connected in series through a wire with a plurality of cells included in any one cell group. One side of the load resistance (R) is connected to the positive terminal of the solar cell (C) through the wire (any one of L1 to L6), the other side is connected to the negative terminal of the solar cell (C) through the wire Connected.

The hall sensor HS outputs the value of the cell group current flowing through the load resistor R as a corresponding voltage. That is, one Hall sensor HS is connected between the wire and the load resistor R. When current flows through this wire, a magnetic field is generated around the wire. The Hall sensor HS detects the magnetic field and outputs a voltage corresponding to the magnetic field.

The noise filter part NF removes noise from the voltage output from the hall sensor HS.

The amplifier AP amplifies the voltage from the noise filter unit NF. The voltage from this amplifier AP is supplied to the data analyzer DA. The data analyzer DA includes an analog-digital converter for converting the voltage into digital.

5 is a detailed configuration diagram of a cell group voltage measuring unit, and FIG. 6 is a diagram illustrating a connection relationship between the voltage measuring units and the cell groups of FIG. 5.

As shown in FIG. 5, the cell group voltage measuring unit CVG includes a plurality of voltage measuring units CV1 to CV6 for measuring the cell group voltage of each cell group. One voltage measuring section is connected to one end of the wires (any one of L1 to L6). One voltage measuring unit measures voltages of the solar cells C included in one cell group. This voltage is the cell group voltage.

Each voltage measuring unit CV1 to CV6 includes a noise filter unit NF and an amplifier unit AP.

The noise filter NF removes noise from the cell group voltages output from a plurality of cells included in any one cell group.

The amplifier AP amplifies the cell group voltage from the noise filter unit NF. The cell group voltage from this amplifier AP is supplied to the data analyzer DA. The data analyzer DA includes an analog-digital converter for converting the voltage into digital.

FIG. 7 is a view illustrating first to third noise filter units NF and first to third amplifiers AP1 to AP3 provided in the cleaning determination unit 103.

As shown in FIG. 7, the measured value output from the solar radiation measuring unit 201 is supplied to the data analyzing unit DA through the first noise filter unit NF1 and the first amplifying unit AP1, and the temperature measuring unit The measured value output from the 202 is supplied to the data analyzer DA through the second noise filter NF2 and the second amplifier AP2, and the measured value output from the foreign matter measuring unit 203 The data is supplied to the data analyzer DA through the noise filter NF3 and the third amplifier AP3.

The data analyzer DA includes an analog-to-digital converter for converting measured values (voltages) supplied to the data analyzer DA through the first to third amplifiers AP1 to AP3 into digital data.

On the other hand, the cleaning determination unit 103 may further include a central processing unit for controlling the operation of the cell group current measuring unit (CGC), the group voltage measuring unit and the data analysis unit (DA). In this case, as described above, when the pollution indicator 102 further includes the solar radiation measurement unit 201, the temperature measurement unit 202, and the foreign matter measurement unit 203, the central processing unit may include a cell group current measurement unit (CGC). ), The cell group voltage measurement unit CGV, the first to third noise filter units NF, the first to third amplifiers AP1 to AP3, and the data analyzer DA are controlled.

In addition, the cleaning unit 103 is a data storage unit for storing the digital data from the data analysis unit DA, and a communication module for transmitting the digital data stored in the data storage unit to the outside under control from the central processing unit It may further include.

The communication module transmits the digital data to the outside using at least one of a wired LAN method and a wireless LAN method.

When transmitting via wired LAN, the above-mentioned digital data is transmitted according to the MODBUS protocol through the RS-485 communication line. In the case of transmission via a wireless LAN, the above-mentioned digital data is transmitted to the outside according to the TCP / IP wireless communication protocol through an IEEE 802.11n Wi-Fi wireless communication medium.

The data analyzer DA analyzes the digital data as described above, and determines whether the solar sensor modules are cleaned based on the analysis. As a result of this determination, when the solar sensor modules need cleaning, a message indicating that the cleaning is necessary may be transmitted to the external user's terminal through the communication module.

In addition, digital data of the data analyzer DA may also be transmitted to an external user's terminal. The user may determine whether the solar sensor module 101 is cleaned by processing the digital data using an analysis program installed in the terminal.

8 is a detailed configuration diagram of the solar radiation measuring unit 201.

As shown in FIG. 8, the solar radiation measurement unit 201 includes a temperature sensor 302, a temperature compensation circuit 301, and a single crystal solar cell 303.

The above-described temperature measuring unit 202 may be replaced by a temperature sensor built in the solar radiation measuring unit 201. That is, the surface temperature of the contamination indicator 102 may be measured using a temperature sensor built into the solar radiation measurement unit 201 without using a separate temperature measurement unit 202.

9 is a diagram showing another example of the configuration of the pollution indicator 102.

As shown in FIG. 9, the solar radiation measurement unit 201 is installed at the lower left corner of the incident surface 222 of the pollution indicator 102, and the foreign matter measurement unit 203 is located at the contamination indicator 102. It may be installed on the bottom right corner of the incident surface 222. Here, the solar radiation measuring unit 201 has a temperature sensor as shown in FIG.

In this configuration, the solar cells C positioned at the bottom of the incident surface 222 are not used to measure the amount of foreign matter.

When the pollution indicator unit 102 is configured as shown in FIG. 9, since the solar radiation measurement unit 201 and the foreign matter measurement unit 203 do not protrude to the outside of the pollution indicator unit 102, the pollution indicator unit 102 is used. It can increase the space utilization of.

10 is a view showing a solar system according to a second embodiment of the present invention.

In the photovoltaic power generation system according to the second embodiment of the present invention, as shown in FIG. 10, the pollution indicator 102 is located between the photovoltaic sensor modules 101. That is, a plurality of photovoltaic sensor modules 101 are gathered to form a photovoltaic array 888, and the pollution indicator may be located in the photovoltaic array 888. In this case, the pollution indicator 102 may be selected from any one of the solar sensor modules 101. That is, when there are a plurality of solar sensor modules 101, one of them may be selected and the selected solar sensor module 101 may be set as the pollution indicator unit 102. At this time, the contamination indicator 102 may have a structure as shown in FIG.

Referring to the method of determining the cleaning time of the solar sensor module using the photovoltaic power generation system of the present invention configured as described above are as follows.

11 is a flowchart illustrating a method of determining a cleaning time of a solar sensor module of a solar power generation system according to a first embodiment of the present invention.

First, as shown in step S1, a plurality of solar cells formed on the incident surface of the contamination indicator portion is grouped. That is, a plurality of solar cells arranged in a direction perpendicular to the direction of gravity is defined as one cell group. The contamination indicator portion may be the pollution indicator portion described with reference to FIGS. 1 to 10.

Subsequently, the cell group current and the cell group voltage of each cell group are measured, and it is determined whether the solar module sensors are cleaned based on at least one of the measured cell group current and the cell group voltages. This washing determination step is subdivided as follows.

That is, as shown in step S2, the cell group currents generated by the solar cell included in each cell group when the foreign matter is not formed in the solar cell of the pollution indicator unit is measured. This step S2 measures the cell group currents generated by the solar cells of the pollution indicator section before the pollution indicator section is exposed to the external environment. In the optimal state, the cell group currents generated by the solar cells of the contamination indicator unit are measured. The measured cell group currents are defined as reference cell group currents. As described above, if these cell groups are six in total, the reference cell group currents are also six.

On the other hand, these reference cell group currents can also be measured in the following manner. That is, a plurality of solar sensor modules are also grouped in the same manner as the pollution indicator part, and the solar cell cells included in each cell group when no foreign matter is formed in the solar sensor modules and the solar cell cells of the pollution material part. Measure the cell group currents generated by Thereafter, the measured values of the cell groups corresponding to the solar cell line modules and the pollution indicators may be averaged, and the averaged cell group current may be set as the reference cell group current of the corresponding cell group. For example, a value obtained by averaging the cell group currents measured from the first cell groups of the solar sensor modules and the pollution indicator unit may be set as the first reference cell group current of the first cell group.

Next, as shown in step S3, the pollution indicator unit is installed outside, and the cell group currents generated by the solar cells included in each cell group are measured at predetermined time intervals. The outside means a place where the solar sensor modules are installed, and specifically, a place where power can be generated by receiving real sunlight.

Subsequently, as shown in step S4, each of the measured cell group currents and the preset first threshold value are compared every predetermined time. As a result of this comparison, if all of these cell group currents are larger than the first threshold value, the process returns to step S3 to measure the cell group currents again. However, as a result of the comparison in step S4, if any one of these cell group currents is less than or equal to the first threshold, the process proceeds to step S5.

In this step S5, the values of the cell group currents which are less than or equal to the first threshold value among the cell group currents measured at the most recent time are compared. Then, the cell group current having the smallest value among them is selected. When there are two or more cell group currents having the most value, one of the cell group currents having the same value may be randomly selected.

Thereafter, as shown in step S6, the average decrease amount of the cell group current selected from step S5 is calculated. In other words, in this step S6, the amount of time decrease until the selected cell group current reaches the first threshold (or the first value smaller than the first threshold) from the value of the initial reference cell group current is calculated. It means the total time from when the selected cell group current reaches the first threshold (or an initial value smaller than the first threshold) from the initial reference cell group current. The selected cell group current and the reference cell group current are both measurement elements measured by the same cell group. For example, the selected cell group current and the reference cell group current are measured by the solar cells of the first cell group. will be.

Subsequently, as shown in step S7, the decrease amount of the selected cell group current is linearly approximated, and based on the approximated decrease amount, an estimated time at which the selected cell group current reaches the second threshold is reported and notified to the user. . This estimated time means the cleaning time of the solar sensor modules. That is, in step S7, the user can have a sufficient response time by notifying when the cleaning time is days or months before the calculated cleaning time.

The above-mentioned first and second thresholds both have a value corresponding to n% (n is a natural number less than 100) of the reference cell group current corresponding to the selected cell group current. The first and second thresholds are selected cells. The value may vary depending on the reference cell group current corresponding to the group current. For example, if a first cell group current is selected from a total of six cell group currents, the first and second thresholds are set according to the first reference cell group current corresponding to the first cell group current. do. At this time, the second threshold has a smaller value than the first threshold. The second threshold may be set to the cell group current measured in a state in which the solar sensor module is not suitable for power generation, and the first threshold may be set to have a smaller value than this second threshold.

On the other hand, in the present invention, more accurate washing anticipation time can be determined by considering the amount of external solar radiation, temperature and dust. If this is explained in more detail as follows.

12 is a flowchart illustrating a method of determining a cleaning time of a photovoltaic sensor module of a photovoltaic system according to a second embodiment of the present invention.

The washing time determining method according to the second embodiment of the present invention, as shown in FIG. 12, includes steps 1 to 12. Steps 1 to 7 of these steps 1 to 12 are the same as steps 1 to 7 in the above-described first embodiment. However, the estimated washing time calculated in step 7 of the second embodiment is not immediately notified to the user, but is corrected through the following several steps and notified to the user.

That is, after step S7, the amount of solar radiation applied to the incident surface of the contamination indicator portion is measured (step S8). This insolation amount is measured by the above insolation measurement section.

Then, as shown in step S9, the temperature of the incident surface of the contamination indicator portion is measured. This temperature is measured by the temperature measuring part mentioned above.

Next, as shown in step S10, the amount of foreign matter suspended around the incident surface surface of the contamination indicator portion is measured. The amount of this foreign matter is measured by the foreign matter measuring unit described above. This foreign material means dust.

Here, steps S8 to S10 may be performed at the same time. That is, the amount of insolation, temperature and the amount of foreign matter can be measured simultaneously.

Then, based on the amount of insolation, temperature and the amount of foreign matter as described above, the estimated time calculated in step 6 is adjusted (step S11). That is, the amount of insolation, temperature and the amount of foreign matter is divided into m steps (m is a natural number of two or more) according to the value. In this step S11, each step representing the measured amount of insolation and temperature represents the amount of foreign matter. The expected time is advanced when it has a higher value. This is because the cell group current may increase depending on the amount of insolation and temperature. That is, even if the amount of dust is large, it is more preferable that the estimated time may be delayed because the estimated time may be delayed due to a slight increase in the cell group current depending on the amount of insolation and temperature.

On the other hand, when any one of the steps indicating the amount of insolation and temperature measured has a value equal to or lower than the step indicating the amount of foreign matter, it maintains the expected time determined in step S7.

FIG. 13 is a view illustrating a cleaning time determination method of a solar sensor module according to first and second embodiments of the present invention.

As shown in Fig. 13, the selected cell group current decreases with time. The approximated straight line is a linear approximation of the reduction amount of the selected cell group current. According to the present invention, the time at which the cell group current reaches the second threshold from the first threshold value is calculated in advance according to this approximated straight line and notified to the user. At this time, as mentioned in FIG. 12, when each step representing the measured solar radiation and temperature has a higher value than the step indicating the amount of foreign matter, the estimated time is advanced as indicated by the dotted line.

The cell group current described in FIGS. 11 to 13 is measured based on the voltage value corresponding to this cell group current. That is, as described above in Figs. 1 to 10, this cell group current is converted into a voltage value by the Hall sensor.

Meanwhile, in the present invention, the cleaning time may be determined using the cell group voltage instead of the cell group current described above. That is, when the cell group current is changed to the cell group voltage and the reference cell group current is replaced with the reference cell group voltage in FIGS. 11 and 12 and related details, the cleaning timing determination method according to the cell group voltage becomes.

Meanwhile, in the present invention, a faster expected time may be selected as the cleaning time by comparing the expected time calculated by the cell group currents and the expected time calculated by the cell group voltages. For example, the expected time calculated by the cell group current, FIG. 11 and the corresponding description and the expected time calculated by the cell group voltage, FIG. Judging by Similarly, the expected time calculated by the cell group current, FIG. 12 and the corresponding description and the expected time calculated by the cell group voltage, FIG. 12 and the corresponding description are compared with each other, and the faster estimated time is determined as the cleaning time. can do.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

Claims (6)

Cleaning of the solar sensor module of the photovoltaic system comprising a plurality of solar sensor modules for converting sunlight into electrical energy and at least one pollution indicator exposed to the same environment as the plurality of solar sensor modules In the timing judgment method,
A grouping a plurality of solar cells formed on the incident surface of the contamination indicator unit, defining a plurality of solar cells arranged in a direction perpendicular to the gravity direction as a cell group; And,
Measuring cell group current and cell group voltage of each cell group, and determining whether to clean the solar module sensors based on at least one of the measured cell group current and cell group voltages. Method for determining the cleaning time of the solar sensor module of the photovoltaic power generation system. The method of claim 1,
Step B,
A step B-1 of measuring cell group currents generated by solar cells included in each cell group when no foreign matter is formed in the solar cells of the pollution indicator unit;
Setting the measured cell group currents as reference cell group currents, respectively;
The pollution indicator is installed externally, and the cell group currents generated by the solar cells included in each cell group are measured at predetermined times, and each of the measured cell group currents and the first predetermined threshold are set at a predetermined time. A step B-3 comparing each time;
Step B-4 of selecting one cell group current having the smallest value among the cell group currents having a value smaller than the first threshold;
A step B-5 of calculating an average decrease amount of the cell group current selected in the step B-4;
Linearly approximating the decrease in the selected cell group current and calculating an expected time for the selected cell group current to reach a second threshold based on the approximated decrease, and notifying the user of the decrease;
The second threshold is less than the first threshold;
The second threshold has a value corresponding to n% (n is a natural number less than 100) of the reference cell group current corresponding to the selected cell group current. Judgment method. The method of claim 2,
Step B,
A step B-1 of measuring cell group currents generated by solar cells included in each cell group when no foreign matter is formed in the solar cells of the pollution indicator unit;
Setting the measured cell group currents as reference cell group currents, respectively;
The pollution indicator is installed externally, and the cell group currents generated by the solar cells included in each cell group are measured at predetermined times, and each of the measured cell group currents and the first predetermined threshold are set at a predetermined time. A step B-3 comparing each time;
Step B-4 of selecting one cell group current having the smallest value among the cell group currents having a value smaller than the first threshold;
A step B-5 of calculating an average decrease amount of the cell group current selected in step B-4;
Linearly approximating the decrease amount of the selected cell group current and calculating an expected time for the selected cell group current to reach a second threshold based on the approximated decrease amount;
B-7 step of measuring the amount of solar radiation applied to the incident surface of the contamination indicator portion;
B-8 step of measuring the temperature of the surface of the incident surface of the contamination indicator;
B-9 measuring the amount of foreign matter floating around the surface of the incident surface of the contamination indicator;
A step B-10 for adjusting the estimated time based on the amount of insolation in step B-7, the temperature in step B-8 and the amount of foreign matter in step B-9;
The second threshold is less than the first threshold;
The second threshold has a value corresponding to n% (n is a natural number less than 100) of the reference cell group current corresponding to the selected cell group current. Judgment method. The method of claim 3, wherein
The amount of insolation, temperature and the amount of foreign matter are divided into m steps (m is a natural number of two or more) according to the value thereof;
Step B,
Advance the estimated time when each step representing the measured insolation and temperature has a higher value than the step representing the amount of foreign matter, and any one of the steps indicative of the measured insolation and temperature represents the amount of foreign matter Method of determining the cleaning time of the solar sensor module of the photovoltaic system, characterized in that it maintains the estimated time in the step B-6 when it has a lower value than the step. The method of claim 1,
The pollution indicator unit is a cleaning time determination method of the solar sensor module of the photovoltaic system, characterized in that at least one of the plurality of solar sensor modules. The method of claim 1,
Each solar sensor module and pollution indicator portion includes an incident surface on which a plurality of solar cells for converting sunlight into electrical energy are formed;
The area and the shape of the incident surface of the solar sensor module are the same as the area and the shape of the incident surface of the contamination indicator; And,
The number, type, shape, and size of the solar cells formed in the solar sensor module are the same as the number, type, shape, and size of the solar cells formed in the pollution indicator. How to determine when to clean the sensor module.

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