JP2011181706A - Solar cell with output relaxing function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell including an output relaxing function to assist an individual operation-detecting function so that when two or more photovoltaic power generators are installed in one bank, a function of detecting an individual operation of an inverter may reliably operate. <P>SOLUTION: The solar cell 1 with the output relaxing function is characterized in that a metal electrode layer 102, a semiconductor layer 103 joined to the metal electrode layer, a transparent electrode layer 104 joined to the semiconductor layer, and a light transmittance control layer 105 joined to the transparent electrode layer are formed in order, a control IC controlling the light transmittance control layer includes a power generation amount-measuring means for the semiconductor layer and a comparison operation means for changing light transmittance in a direction where change in power generation amount is canceled in accordance with measured change in power generation amount, and the comparison operation means sets at random and changes a relaxation time up to when the light transmittance is put back till the original light transmittance from the changed state. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a solar cell, and more particularly to a solar cell having a function of mitigating short-time output fluctuations in a solar cell.

In recent years, distributed power supply systems have been widely used. For example, distributed power sources such as solar cells, fuel cells, and micro gas turbines are often installed in close proximity to user loads, such as ordinary homes, apartment houses, and small businesses, to supply power to users.

FIG. 2 of Patent Document 1 shows an example of a distributed power supply system using a solar cell as a power generation source. In FIG. 2, the distributed power supply system includes a solar cell array 1 and power conversion means 4 incorporating an inverter 24 that converts DC power output from the solar cell array 1 into AC power. This power conversion means 4 detects the disconnection of the circuit breaker 25 that disconnects the distributed power from the commercial power system 11 and the circuit breaker 26 of the commercial power system 11 based on frequency fluctuations and voltage fluctuations, and disconnects the circuit breaker 25. The system interconnection protection device including the isolated operation detecting means 27 is built in.

And as disclosed in Patent Document 2, the inverter provided in the solar power generation device has a function of controlling the AC output voltage of the inverter to a constant voltage by the included control circuit, that is, a function of suppressing a voltage increase, And has a function of detecting isolated operation.

As for the function for detecting the independent operation of the inverter, as shown in Patent Document 2, when a system power failure occurs due to construction or the like while the output voltage of the inverter is connected to the power system, the inverter Is to stop. If the inverter remains in an operating state, the inverter output voltage is applied to the construction section of the power system due to the independent operation of the inverter, and there is a risk of electric shock to construction workers and the like. Therefore, the function of detecting the isolated operation is to detect a change in voltage due to the application of the output voltage of the inverter in the system power failure state and stop the inverter.

Regarding the detection function of the isolated operation, particularly when a plurality of private power generators are connected to the same pole transformer in the power system, whether or not this detection function works effectively is an important issue. In other words, if two private power generators are installed in the same area (called “bank”) where the pole transformer of the power system is the same, even if a system power failure occurs, When power is supplied, it may be difficult for the other inverter to detect a change in voltage due to the application of the output voltage and stop the inverter. Therefore, it is necessary to confirm in advance whether or not the function for detecting an isolated operation surely works between an existing private power generation device and a new private power generation device in the same bank. This confirmation work is often performed exclusively by electric power companies.

Moreover, in patent document 2, when two or more photovoltaic power generation apparatuses are installed in the same bank, the weather in the same bank is almost the same, so the power generation amount of any power generation apparatus is the same. Transition to For this reason, even if the amount of power generated is clear enough, the reverse power flow in the same bank will increase, causing the voltage in the same bank to rise temporarily and it is not possible to sell power to the power company. Has also been shown to occur.

JP 2002-152976 A JP 2008-77369 A

As described above, since the power generation is conventionally performed on the consumer side supplied with the commercial power from the electric power company, the cooperation between the electric power company side and the customer side is considered. And grasping becomes important. In particular, in the case where two or more photovoltaic power generation devices are installed in the same bank, only the power generation device on the customer side continues the power generation operation in a state where a system power failure occurs on the power provider side. It has become an important issue to provide a function for reliably detecting and stopping the inverter.

Therefore, the present invention has been made in view of the above problems, and when the two or more photovoltaic power generators are installed in the same bank, the output is reduced so that the function of detecting an independent operation in the inverter works reliably. An object of the present invention is to provide a solar cell that has a function and assists an isolated operation detection function.

The solar cell according to the present invention is configured to solve the above-described problems,
A metal electrode layer, a semiconductor layer bonded to the metal electrode layer, a transparent electrode layer bonded to the semiconductor layer, and a light transmittance control layer bonded to the transparent electrode layer are sequentially formed, and conductive The light-transmitting control layer control IC electrically connected to the current collecting electrode provided on the transparent electrode layer and the metal electrode is provided on the conductive substrate. The control IC includes a power generation amount measurement unit in the semiconductor layer, and a comparison calculation unit that changes the transmissivity from the initial state in a direction to cancel the change in the power generation amount according to the change in the measured power generation amount. Then, by the comparison calculation means, a relaxation time from the state where the light transmittance is changed to the time when the light transmittance is returned to the original light transmittance is randomly set, and the state where the light transmittance is changed is changed to the original light transmittance. Characterized by controlling to change the relaxation time to return It may constitute a solar cell having a force relaxation function.

According to this configuration, when the power generation amount changes due to an increase in the amount of light after the solar cell is installed and used, the transmissivity is changed in a direction to cancel the change in the power generation amount, and the change is restored. In order to perform control by randomly setting a relaxation time until returning to the case, when a plurality of solar cells are provided, it is possible to disperse the timing of the increase in the power output from the solar cells, It is possible to provide a solar cell having an output relaxation function that can reliably detect driving.

Further, the solar cell according to the present invention stores threshold data that defines the magnitude of the change in the amount of power generation in the memory unit of the comparison calculation means, and the power generation amount measured by the threshold data and the power generation amount measurement means. The solar cell having an output mitigation function according to claim 1, wherein the light transmission rate is changed when the change data of the power generation amount exceeds the threshold data by comparing with the change data. .

According to such a configuration, in the case of a change in the amount of power generation that does not satisfy the predetermined threshold, it is possible to reduce the power related to the control without changing the light transmittance.

Further, the solar cell according to the present invention stores the power generation amount-transmittance correspondence data in which the power generation amount change data and the light transmittance change data are associated with each other in advance in the memory unit of the comparison operation unit, and the comparison The calculation means reads the change data of the light transmittance according to the measured change in the power generation amount from the memory unit, calculates the magnitude of the light transmittance to be changed according to the change in the power generation amount, and calculates the change in the power generation amount. The solar cell having an output relaxation function according to claim 1 or 2, wherein the transmissivity is changed in the direction of cancellation.

According to such a configuration, by storing the power generation amount-transmittance correspondence data according to the characteristics of the solar cell, it is possible to perform control for appropriately changing the transmittance according to the actual solar cell.

As described above, according to the present invention, when two or more photovoltaic power generation devices are installed in the same bank, the inverter operates independently even if the weather changes in the same bank are almost the same. In order to ensure that the function of detecting the solar battery functions, a solar cell having an output relaxation function and assisting the isolated operation detection function can be provided.

The schematic block diagram of the solar cell element which shows 1st Embodiment is shown. The schematic block diagram of the translucency control layer which concerns on the same embodiment is shown. The block block diagram of the control IC which concerns on the embodiment is shown. The data memorize | stored in the memory of control IC concerning the embodiment are shown. The change of the light quantity, electric power generation amount, and the light transmittance which concern on the embodiment is shown. The figure which connected and provided multiple solar cells is shown.

Next, an embodiment of the present invention will be described in detail with reference to FIGS.

(First embodiment)
(Description of solar cell)
FIG. 1 is a schematic configuration diagram showing a first embodiment of a solar cell in the present invention. FIG. 1 shows a cross section of a solar cell element having a layered structure in the solar cell 1, and the solar cell element is formed in layers on a conductive substrate 101. On the conductive substrate 101, a metal electrode layer 102, a semiconductor layer 103 bonded to the metal electrode layer 102, a transparent electrode layer 104 bonded to the semiconductor layer 103, and a bond to the transparent electrode layer 104 The translucency control layer 105 to be formed is sequentially formed in layers.

A control IC 106 for controlling the light transmittance control layer 105 is disposed on the conductive substrate 101. The control IC 106 includes a current collecting electrode 107 provided on the transparent electrode layer, A power source is obtained by being electrically connected to the metal electrode layer 102.

The control IC 106 measures a power generation amount in the semiconductor layer, detects a change in the power generation amount as a change with time, and transmits light in a direction to cancel the change in the power generation amount according to the change in the power generation amount. Comparison operation means for changing the light transmittance in the rate control layer and then changing the light transmittance so as to return to the original light transmittance again is provided.

FIG. 3 shows a block diagram of the control IC 106.
The control IC 106 measures a temporal change in the voltage value and the current value input to the power input unit 1061 for obtaining power from the current collecting electrode, and the voltage value and the current value. A comparison operation unit 1063 that determines the amount of change in light transmittance in the light transmittance control layer according to a change over time, and a voltage value corresponding to the amount of change in light transmittance determined by the comparison operation unit 1063 is output. A voltage output unit 1062.

The comparison calculation unit 1063 includes a power generation amount measurement unit 10631 that measures a temporal change in voltage input from the power input unit, and a memory that stores transmittance change data that defines a range in which the transmittance is changed. Unit 10633, a comparison operation unit 10632 that compares the magnitude of temporal change in voltage with the transmittance change data, and determines the amount of change in transmittance according to the magnitude of temporal change in voltage, and time The timer part which counts progress of this is provided.

Further, the comparison operation unit 10632 has a relaxation time setting function for randomly setting a relaxation time until the light transmittance is returned to the original light transmittance after changing the light transmittance from the original light transmittance.
The relaxation time here means a set time until the light transmittance is returned to the original light transmittance after changing the light transmittance from the original light transmittance, and the magnitude of the temporal change of the voltage is large. In this case, the relaxation time is set large, and when the magnitude of temporal change in the voltage is small, the relaxation time is set small.

The relaxation time being random means that the magnitude of temporal change in the voltage is compared with the transmittance change data, and the relaxation time determined according to the magnitude of the temporal change in voltage is predetermined. It is to change with the time width of. For example, when the magnitude of the voltage change over time is large, the relaxation time is set large, and when the magnitude of the voltage change over time is small, the relaxation time is set small. For this reason, the predetermined time width is set large for a large relaxation time, and the predetermined time width is also set small for a small relaxation time. That is, it is preferable to set a ratio with respect to the relaxation time and to provide a predetermined time width for the relaxation time.

(Description of translucency control layer)
The light transmittance control layer 105 controls the light transmittance of the semiconductor layer 103 and thereby controls the amount of sunlight irradiated to the semiconductor layer 103. In this embodiment, the liquid crystal is used to change the molecular orientation by applying a voltage.
FIG. 2 shows a schematic configuration diagram of the light transmittance control layer 105.

FIG. 2 shows a cross section of the translucency control layer 105, and the translucency control layer 105 is formed on the transparent electrode layer 104 in layers. The light transmittance control layer 105 includes a polarizing plate 1051 bonded to the transparent electrode layer 104, a transparent electrode layer 1052 bonded to the polarizing plate 1051, and two alignment layers 1053 bonded to the transparent electrode layer 1052. A liquid crystal layer 1055 sandwiched between 1054, a transparent electrode layer 1056 bonded to the liquid crystal layer 1055, and a polarizing plate 1057 bonded to the transparent electrode layer 1056 are formed in layers.

The transparent electrodes 1052 and 1056 in the light transmittance control layer 105 are electrically connected to the control IC 106. The liquid crystal 1055 changes the orientation of the liquid crystal 1055 by controlling the application state of power from the control IC 106.

(Explanation of control)
Next, the control flow will be described.
The power generation amount measurement unit 10631 converts the voltage value and current value generated by the semiconductor layer input to the power input unit 1061 into digital data by A / D conversion, and outputs the digital data to the comparison unit 10632.

The comparison unit 10632 monitors the power generation amount converted into digital data at a predetermined interval, and obtains a temporal change in the power generation amount through arithmetic processing. When the amount of power generation changes with time, the transmittance change data is read from the memory unit 10633, and applied voltage data for changing the transmittance is obtained based on the transmittance change data. Then, the applied voltage data is output from the comparison unit 10632 to the power output unit 1062, and the power output unit 1062 controls the voltage to be applied to the light transmittance control layer based on the applied voltage data, and the light transmittance is obtained. Change.

As data stored in the memory unit 10633, for example, a data table in which a change amount of light transmittance, an input voltage change amount, an output voltage value, and the relaxation time are associated with each other is stored. Accordingly, the comparison unit 10632 can uniquely read the magnitude of the output voltage and the relaxation time corresponding to the amount of change in the input voltage, and can quickly transmit the light according to the temporal change in the input voltage value. Rate control can be performed.

Next, changes in the light amount, power generation amount, and transmissivity when the transmissivity control layer 105 is controlled by the control IC 106 will be described with reference to FIG. FIG. 5A shows the change in the amount of light over time, FIG. 5B shows the change in the amount of power generated in the solar cell, and FIG. 5C shows the change in the transmissivity. In each case, the horizontal axis represents time, and the vertical axis represents light amount, power generation amount, and light transmittance, respectively.

First, the amount of light may greatly increased from A ₀ to A _B, generally the power generation amount in the solar cell is greatly increased following the increase in light intensity. In the solar cell 1 according to the present embodiment, by using the power generation amount data digitized by the power generation amount measurement unit 10631, a temporal change in the power generation amount is obtained by an arithmetic process, and the transparent data stored in the memory unit 10633 is obtained. Based on the light rate change data, applied voltage data corresponding to the time change of the power generation amount is obtained. Based on the voltage output from the power supply output unit 1062 based on the applied voltage data, the transmissivity is changed from τ ₀ to τ _B in a direction to cancel the power generation due to the time change of the light amount, and the time change of the light amount is suppressed. In such a case, the change is relaxed over a predetermined time so as to approach τ ₀ from τ _B.

That is, the comparison unit 10632 performs control so that the output voltage from the power output unit 1062 gradually changes over a predetermined time. At this time, the comparison unit 10632 randomly changes the relaxation time by a predetermined ratio based on the relaxation time stored in the data table, and uses the relaxation time to change the light transmittance to the original light transmission rate. Change the rate. As a result, the change in the amount of power generated in the solar cell 1 does not become a change that rapidly increases from P ₀ to P _B following the increase in the amount of light, but gradually relaxes from P ₀ to P _B. Change will increase.

When a plurality of solar power generation devices using the solar cell 1 are provided in the same bank, even if the weather in the same bank is almost the same, the above-described relaxation time is provided at random, There is a difference in recovery. For this reason, it becomes easy to detect a change in voltage in the inverter, and it becomes possible to reliably detect an isolated operation.

Subsequently, when the light amount decreases from A _B to A _A , in the solar cell 1 according to the present embodiment, the transmissivity is changed from τ _A to τ in the direction to cancel the power generation due to the temporal change in the light amount. _When it is changed to ₀ and the time change of the light quantity is settled, it is changed moderately so as to approach τ ₀ from τ _A. Thus, the power generation amount of change in the solar cell 1 toward the P _B to P _A, a change that increases gradually relaxed manner. Similar control is performed when the amount of light decreases from A _A to A ₀ .

As described above, the magnitude (ΔP1, ΔP2) of the change in the power generation amount due to the change in the light quantity (ΔA1, ΔA2) is the same as that of a general solar cell, but is obtained according to the magnitude of the change in the light quantity and the time change. In addition, in order to relieve the change in light transmittance (τ ₁ , τ ₂ ) at random in time, a change in the amount of power generation occurs randomly in each solar power generation device, and the inverter connected to the solar cell 1 is It becomes easier to detect a change in voltage, and it becomes possible to reliably detect an isolated operation.

For example, regarding the length of the relaxation time when a moderate change is made so as to approach τ ₀ from τ _B , the power generation amount greatly changes based on the magnitude of the change in power generation amount (ΔA1, ΔA2, etc.). In this case, the relaxation time is set long so that the load on the inverter can be reduced, and when the change in power generation amount is small, the load on the inverter is also small, so the relaxation time is set short. A relational expression between the magnitude of change in amount and the length of relaxation time is stored in the memory unit, and the magnitude of change in power generation amount measured by the power generation amount measuring unit 10631 is applied to the relational expression to increase the relaxation time. It is also possible to perform control to obtain the length and to randomly generate a ratio to be changed with respect to the obtained relaxation time and multiply the result to randomly set the relaxation time.

(Second Embodiment)
Next, the second embodiment will be described.
The difference from the first embodiment is that the amount of time change of the power generation amount obtained by the arithmetic processing is monitored, and the amount of time change of the power generation amount exceeds the threshold data stored in the memory unit 10633. In this case, control for changing the light transmittance is performed.

The change in the amount of light occurs as needed over time, but the drive power of the control IC is always required when performing control to change the transmissivity even with a slight change in the amount of light. For this reason, a magnitude corresponding to the magnitude of the voltage change that does not burden the inverter is set as threshold data, and the amount of power generation detected by the control IC is larger than the threshold data. In the case where the time change magnitude data is small, control for changing the light transmittance in the comparison unit 10632 is not performed, and when the power generation amount time change data is larger than the threshold data, The comparison operation unit was configured to perform control to change the light transmittance in the comparison unit 10632.

For example, when the voltage that can be generated by the solar cell 1 is 1 V, 0.5 V at which the magnitude of the time change of the voltage value is half of the voltage that can be generated is set as the threshold data and stored in the memory unit 10633. Keep it. The comparison unit 10632 compares the power generation voltage value data obtained by the power generation amount measurement unit 10631 with the threshold data, and performs control of the light transmittance when the power generation voltage value data is less than the threshold data. Absent.

(Third embodiment)
Next, a third embodiment will be described.
The difference from the first embodiment is that the power generation amount-transmittance correspondence data in which the power generation amount change data and the light transmittance change data are associated with each other is stored in advance in the memory unit, and the comparison operation unit 1063 is The point is to read the change data of the transmissivity according to the change of the measured power generation amount from the memory unit, calculate the magnitude of the transmissivity to be changed according to the change of the power generation amount, and perform control to change it. .

FIG. 4 shows an example of the power generation amount-transmittance correspondence data. This data is suitable for the semiconductor layer in the solar cell 1 and corresponds to the magnitude of the change in transmissivity and the magnitude of the applied voltage applied to the transmissivity control layer with respect to the magnitude of the change in power generation over time. Data. The semiconductor layer used in the solar cell has a different amount of power generation with respect to the amount of light depending on the type of semiconductor used. For this reason, the memory unit stores data corresponding to the amount of change in transmissivity with respect to time variation of the amount of power generation suitable for the semiconductor constituting the solar cell and the magnitude of the applied voltage corresponding to the amount of change in transmissivity. 10633, and at the time of the comparison calculation process in the comparison unit 10632, the power generation amount-transmittance correspondence data is read to calculate the magnitude of the light transmittance to be changed according to the time change of the power generation amount. The transmissivity is changed in a direction that cancels the change in the power generation amount.

Thereby, the control which changes a light transmittance appropriately according to the power generation characteristic of the semiconductor layer used for a solar cell can be performed.

(About the types of solar cells to be controlled)
In addition, as semiconductors used for solar cells, crystalline single crystal silicon, polycrystalline silicon, group IV semiconductors typified by amorphous silicon, GaAs, CdS, CuInSe2, III-V group, II-VI The transmissivity control layer in the present application is also provided in solar cells using compound semiconductors such as Group I, III-VI, etc., organic semiconductors such as phthalocyanine, and dye-sensitized solar cells typified by wet solar cells. Thus, it is possible to control the output by controlling the light transmittance over time and controlling the magnitude of sunlight applied to these semiconductors and the like. In addition, any battery that generates power by being irradiated with light such as sunlight or illumination can be controlled by adjusting the amount of irradiation such as sunlight or illumination.

(Other examples)
When a plurality of solar cells 1 are used for modularization, the solar cells 1 may be connected in series or connected in parallel. FIG. 6A shows an example in which a plurality of solar cells 1 are formed on the conductive substrate 101. Each solar cell is connected by an electrode 108 formed on the conductive substrate 101, and a control IC 106 is provided in each solar cell. When the modules are connected to each other, the electrodes 108 may be sequentially connected.

With respect to the control IC 106 provided on the conductive substrate 101, the electrical connection between the control IC and the electrode may be connected by a fine wire, or may be connected by providing a pattern wiring on the conductive substrate.

FIG. 6B shows an example in which a plurality of solar cells 1 are formed and these solar cells are controlled by one control IC. In this case, power supply to the control IC may be performed from one solar cell or from a plurality of solar cells. In order to increase the efficiency of wiring, the control IC 106 is provided in the middle of the substrate.
In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

For example, in the first embodiment, an example in which liquid crystal is used for the light transmittance control layer 105 is shown. This liquid crystal has been described on the assumption that the orientation of molecules changes with the application of voltage. However, in order to reduce the control power in the control IC and save power, for example, the liquid crystal A ferroelectric liquid crystal having a memory effect that maintains the alignment state may be used. This eliminates the need to always apply a voltage. In the case of changing the light transmittance, it is possible to apply the voltage for a short time and gradually change the light transmittance.

In the case of controlling a plurality of solar cells, a solar cell to be controlled and a solar cell not to be controlled may be provided, and the solar cell not to be controlled may be used as a power source for the control IC 106.

Further, as shown in FIG. 6C, a circuit pattern of the control IC may be prepared in advance adjacent to a semiconductor layer used for the solar cell, and the control IC may be provided integrally with the solar cell. In this case, the wiring for connecting the power supply for the control IC can be eliminated, and the production efficiency can be improved as compared with the case where the solar cell and the control IC are individually produced.

Another example of control is shown below. When a change in the amount of light over time occurs more than a certain amount and a large change in the amount of power generation is predicted, control is performed to change the transmittance with time as follows.

For example, when the temporal change amount of the input voltage measured by the power generation amount measuring unit 10631 is close to the power generation possible voltage, that is, when the output power changes from near zero to the maximum output at once, the first approaches while changing the tau _B of the light transmittance from tau _0, if is increased subsequent light transmittance from tau _B, light transmittance is less than τ ₀ τ _{0 'as} in the embodiment Make a certain modest change. performs control to maintain the status light transmittance is low tau _{0 'predetermined} time than tau _0, even if the time change amount of power generation subsided, a while, to maintain the lower than ₀ light transmittance is tau , Suppress the rapid increase in power generation.

When it is detected that the power generation amount has decreased, control is performed so that the light transmittance is returned to τ ₀ . By performing such control, when the increase in power generation amount is very large, if the single operation is not detected by keeping the light transmittance small so that the power generation amount itself decreases. In addition to suppressing electrical accidents, the burden on the equipment due to the application of high voltage to the inverter connected to the solar cell is reduced.

DESCRIPTION OF SYMBOLS 1 Solar cell 101 Conductive substrate 102 Metal electrode layer 103 Semiconductor layer 104 Transparent electrode layer 105 Light transmittance control layer 1051 Polarizing plate 1052 Transparent electrode 1053 Transparent electrode 1054 Alignment layer 1055 Alignment layer 1056 Liquid crystal 1057 Polarizing plate 106 Control IC
1061 Power input unit 1062 Power output unit 1063 Comparison calculation unit 10631 Power generation amount measurement unit 10632 Comparison unit 10633 Memory unit 107 Current collecting electrode

Claims (3)

A metal electrode layer, a semiconductor layer bonded to the metal electrode layer, a transparent electrode layer bonded to the semiconductor layer, and a light transmittance control layer bonded to the transparent electrode layer are sequentially formed, and conductive And disposed on the conductive substrate,
A current collecting electrode provided on the transparent electrode layer and the light transmittance control layer control IC electrically connected to the metal electrode are disposed on the conductive substrate,
The control IC includes a power generation amount measuring unit in the semiconductor layer,
Comparing calculation means for changing the transmissivity in a direction to cancel the change in the power generation amount according to the change in the power generation amount measured,
The comparison calculation means randomly sets a relaxation time until the light transmittance is returned from the changed state to the original light transmittance, and returns from the changed light transmittance to the original light transmittance. A solar cell provided with an output relaxation function, characterized in that the control is performed so as to change the relaxation time.
Threshold data that defines the amount of change in the amount of power generation is stored in the memory unit in the comparison calculation means, the threshold data is compared with the change data in the power generation amount measured by the power generation amount measurement means, and the power generation amount The solar cell with an output relaxation function according to claim 1, wherein the transmissivity is changed when the change data exceeds the threshold data.
The power generation amount-transmittance correspondence data in which the power generation amount change data and the light transmittance change data are associated with each other is stored in advance in the memory unit of the comparison calculation unit,
The comparison calculation means reads the change data of the light transmittance according to the change of the measured power generation amount from the memory unit,
Calculate the amount of translucency to be changed according to the change in power generation amount,
The solar cell according to claim 1 or 2, wherein the transmissivity is changed in a direction to cancel the change in the amount of power generation.

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