Control method of tandem solar cell

Abstract

A method for controlling a tandem solar cell includes: determining a P-V curve of a silicon solar cell by performing a scan for determining generated power while changing a generated voltage of the silicon solar cell at each fixed period, and performing power generation control of the silicon solar cell at a maximum power point of the P-V curve; predicting an optimal power generation voltage suitable for the perovskite solar cell using information relating to a P-V curve of the silicon solar cell; and performing power generation control of the perovskite solar cell using the optimal power generation voltage.

Description

Technical Field

[0001] This disclosure relates to a control method for tandem solar cells. Background Technology

[0002] A solar cell power generation system is disclosed in Japanese Patent Application Publication No. 2013-152687. Generally, in the power generation control of silicon solar cells, the hill-climbing method (MPPT, Maximum Power Point Tracking) is employed. This method controls power generation by continuously searching for the maximum power point of the solar cell through current control. However, when local shading exists on the solar cell (partial shade on the illuminated side), multiple peaks appear on the PV curve (power-voltage curve). Therefore, it may be impossible to reach the maximum power point among these peaks using the hill-climbing method. Therefore, in the power generation control of silicon solar cells, the power generation is typically scanned at a certain frequency to confirm whether multiple peaks have occurred. Summary of the Invention

[0003] In recent years, tandem solar cells, including silicon solar cells and perovskite solar cells, have been utilized. However, compared to silicon solar cells, perovskite solar cells have a slower response speed, making it difficult to scan the power output to determine the optimal power generation voltage. Therefore, a technology that can efficiently control the power generation of tandem solar cells is desired.

[0004] This disclosure can be implemented as the following technical solution.

[0005] According to one technical solution of this disclosure, a control method for a series-connected solar cell including silicon solar cells and perovskite solar cells is provided.

[0006] The control method includes:

[0007] The PV curve of the silicon solar cell is obtained by scanning the power generation of the silicon solar cell while changing the power generation voltage at regular intervals, and the power generation control of the silicon solar cell is performed based on the maximum power point of the PV curve.

[0008] Information related to the PV curve is used to predict the optimal power generation voltage suitable for the perovskite solar cell; and

[0009] The optimal power generation voltage is used to perform power generation control of the perovskite solar cell.

[0010] According to this control method, information related to the PV curve of silicon solar cells is used to predict the optimal power generation voltage suitable for perovskite solar cells. Therefore, compared to scanning the power generation capacity of perovskite solar cells, efficient power generation control can be performed in a shorter time.

[0011] Among the control methods described above, it could be:

[0012] Information related to the PV curve includes the voltage value at the maximum power point.

[0013] According to this control method, the optimal power generation voltage of perovskite solar cells can be easily predicted using the voltage value of the maximum power point of silicon solar cells.

[0014] Among the control methods described above, it could be:

[0015] Information related to the PV curve includes the voltage and power values ​​at one or more peak power points in the PV curve.

[0016] According to this control method, the optimal power generation voltage of perovskite solar cells can be accurately predicted by using the voltage and power values ​​at more than one peak power point in the PV curve of silicon solar cells.

[0017] Among the control methods described above, it could be:

[0018] Information related to the PV curve includes shape data representing the shape of the PV curve.

[0019] According to this control method, the optimal power generation voltage of perovskite solar cells can be accurately predicted using the shape data of the PV curve of silicon solar cells.

[0020] Among the control methods described above, it could be:

[0021] When the PV curve has more than two peak power points, the information related to the PV curve is used to predict the optimal power generation voltage suitable for the perovskite solar cell, and the optimal power generation voltage is used to perform the power generation control of the perovskite solar cell; and

[0022] MPPT control is performed on the perovskite solar cell when the PV curve has only one peak power point.

[0023] This control method enables efficient power generation control of perovskite solar cells. Attached Figure Description

[0024] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements, and wherein:

[0025] Figure 1 This is a conceptual diagram of the tandem solar cell in the first embodiment;

[0026] Figure 2 This is a block diagram of the solar cell power generation system in the first embodiment;

[0027] Figure 3 This is a coordinate graph showing the PV curve of a silicon solar cell without local shading and the predicted PV curve of a perovskite solar cell.

[0028] Figure 4 This is a coordinate graph showing the PV curve of a silicon solar cell and the predicted PV curve of a perovskite solar cell under local shading conditions.

[0029] Figure 5 This is a flowchart of the power generation control of the series-connected solar cell in the first embodiment;

[0030] Figure 6 This is a flowchart of the power generation control of the series-connected solar cell in the second embodiment. Detailed Implementation

[0031] A. First Implementation

[0032] Figure 1 This is a conceptual diagram of the series-connected solar cell 100 according to the first embodiment. The series-connected solar cell 100 has a structure consisting of a silicon solar cell 110 and a perovskite solar cell 120 stacked together. Both the silicon solar cell 110 and the perovskite solar cell 120 have multiple photoelectric conversion layers. The series-connected solar cell 100 is a four-terminal cell where the silicon solar cell 110 and the perovskite solar cell 120 are not electrically connected. That is, the silicon solar cell 110 has two terminals 112, and the perovskite solar cell 120 also has two terminals 122. The perovskite solar cell 120 mainly absorbs short-wavelength light, which is visible light, while the silicon solar cell absorbs long-wavelength light, ranging from visible light to infrared light.

[0033] Figure 2 This is a block diagram of the solar cell power generation system 300 according to the first embodiment. The solar cell power generation system 300 includes a series-connected solar cell 100 and a control unit 200. The control unit 200 includes a first power generation control unit 210, a second power generation control unit 220, a power generation characteristic prediction unit 230, and a power combining unit 240.

[0034] The first power generation control unit 210 performs power generation control of the silicon solar cell 110. Specifically, the first power generation control unit 210 is configured to perform a first process and a second process. The first process is a process of performing MPPT control of the silicon solar cell 110 using the mountain climbing method. The second process is a process of performing a scan at regular intervals to calculate the power generation while changing the power generation voltage to obtain the PV curve (power-voltage curve) of the silicon solar cell 110.

[0035] The power generation characteristic prediction unit 230 uses information IG1 related to the PV curve of the silicon solar cell 110 to predict the PV curve of the perovskite solar cell 120, and predicts the optimal power generation voltage Vopt suitable for the perovskite solar cell 120. This will be described later.

[0036] The second power generation control unit 220 performs power generation control of the perovskite solar cell 120. Specifically, the second power generation control unit 220 is configured to perform a first process and a second process. The first process is a mountaineering process that performs MPPT control on the perovskite solar cell 120, and the second process is a process that performs power generation control of the perovskite solar cell 120 using the optimal power generation voltage Vopt predicted by the power generation characteristic prediction unit 230.

[0037] The power combining unit 240 combines the power generation power PW1 of the silicon solar cell 110 obtained under the control of the first power generation control unit 210 with the power generation power PW2 of the perovskite solar cell 120 obtained under the control of the second power generation control unit 220 and supplies it to the external load LD.

[0038] The functions of the first power generation control unit 210, the second power generation control unit 220, and the power generation characteristic prediction unit 230 can be implemented by a processor executing a computer program stored in memory. Alternatively, some or all of the functions of the first power generation control unit 210, the second power generation control unit 220, and the power generation characteristic prediction unit 230 can be implemented using hardware circuitry.

[0039] Figure 3 This is a coordinate graph showing the PV curve G1 of the silicon solar cell 110 and the predicted PV curve G2 of the perovskite solar cell 120 under conditions without local shading. "Local shading" refers to a state where a portion of the surface of the tandem solar cell 100 is shaded due to external objects such as clouds, tall buildings, or trees. When the surface of the tandem solar cell 100 is fully illuminated without local shading, the PV curve G1 of the silicon solar cell 110 has a mountain-shaped shape containing only one peak power point PP1. Similarly, the predicted PV curve G2 of the perovskite solar cell 120 also has a mountain-shaped shape containing only one peak power point PP2.

[0040] Figure 4 This is a coordinate graph showing the PV curve G1 of the silicon solar cell 110 and the predicted PV curve G2 of the perovskite solar cell 120 under localized shading. Under localized shading, the PV curve G1 of the silicon solar cell 110 takes on a mountain-like shape containing multiple peak power points PP1_1 and PP1_2. Similarly, the predicted PV curve G2 of the perovskite solar cell 120 also takes on a mountain-like shape containing multiple peak power points PP2_1 and PP2_2. Furthermore, the shape and / or size of the PV curves G1 and G2 vary depending on the number and / or connection method of the photoelectric conversion layers; therefore, Figure 3 and Figure 4 The PV curves G1 and G2 are just examples.

[0041] Figure 3 , Figure 4 The shape of the PV curve G1 of the silicon solar cell 110 shown can be confirmed by performing a scan that calculates the power generation while changing the power generation voltage of the silicon solar cell 110. On the other hand, the perovskite solar cell 120 has a slower response speed to light irradiation compared to the silicon solar cell 110, making it difficult to determine the shape of its PV curve G2 with a practical scan time. Therefore, the power generation characteristic prediction unit 230 uses information IG1 related to the PV curve G1 of the silicon solar cell 110 to predict the optimal power generation voltage Vopt suitable for the perovskite solar cell 120, and the second power generation control unit 220 uses the optimal power generation voltage Vopt to perform power generation control of the perovskite solar cell 120.

[0042] In the first embodiment, such as Figure 3 As shown, even when the PV curve G1 of the silicon solar cell 110 contains only one peak power point PP1, the information IG1 related to the PV curve G1 is used to predict the optimal power generation voltage Vopt suitable for the perovskite solar cell 120. However, even when the PV curve G1 contains only one peak power point PP1, MPPT control can still be performed on the perovskite solar cell 120. This will be explained in the second embodiment.

[0043] Information IG1 relating to the PV curve G1 of the silicon solar cell 110 can, for example, be any one of information IG1_a to information IG1_c. Information IG1_a is the voltage value of the maximum power point of the PV curve G1. Information IG1_b is the voltage and power values ​​of one or more peak power points PP1 in the PV curve G1. Information IG1_c is shape data representing the shape of the PV curve G1. The shape data representing the shape of the PV curve G1 is, for example, one-dimensional data representing the power generation values ​​corresponding to multiple voltage values ​​set at certain intervals.

[0044] The optimal power generation voltage Vopt of the perovskite solar cell 120 is the voltage corresponding to the maximum power point in the predicted PV curve G2 of the perovskite solar cell 120. The second power generation control unit 220 uses the predicted optimal power generation voltage Vopt to perform power generation control of the perovskite solar cell 120. In this way, compared with the case of scanning the perovskite solar cell 120 in relation to power generation, efficient power generation control can be performed in a short time.

[0045] The prediction function of the power generation characteristic prediction unit 230 can be implemented, for example, by a mapping representing the relationship between information IG1 related to the PV curve G1 and the optimal power generation voltage Vopt. Alternatively, it can be implemented by using a lookup table that takes information IG1 related to the PV curve G1 as input and the optimal power generation voltage Vopt as output. Furthermore, the function of the power generation characteristic prediction unit 230 can also be implemented using a machine learning model that takes information IG1 related to the PV curve G1 as input and the optimal power generation voltage Vopt as output.

[0046] Figure 5 This is a flowchart of the power generation control of the series-connected solar cell 100 in the first embodiment. In S10, the first power generation control unit 210 and the second power generation control unit 220 perform MPPT control on the silicon solar cell 110 and the perovskite solar cell 120, respectively.

[0047] In S20, the first power generation control unit 210 determines whether it is timed to perform a scan related to the power generation of the silicon solar cell 110. The scan related to the power generation of the silicon solar cell 110 is performed at a certain period. The scan period is, for example, preset to approximately 1 minute to several minutes. Furthermore, the time taken for one scan is several seconds to tens of seconds. If it is not timed to perform a scan, the system returns to S10 and continues MPPT control of the silicon solar cell 110 and the perovskite solar cell 120. On the other hand, if the scan execution time has been reached, the system proceeds to S20 to S30.

[0048] In S30, the first power generation control unit 210 performs a scan related to the power generation of the silicon solar cell 110 to determine the PV curve G1, and performs power generation control of the silicon solar cell 110 based on its maximum power point. Figure 3 In the example, the maximum power point of the silicon solar cell 110 is the only peak power point PP1. Figure 4 In the example, the maximum power point of the silicon solar cell 110 is the point PP1_1 with the largest power value among the multiple peak power points PP1_1 and PP1_2.

[0049] In S40, the power generation characteristic prediction unit 230 uses information IG1 related to the PV curve G1 of the silicon solar cell 110 to predict the optimal power generation voltage Vopt of the perovskite solar cell 120. In S50, the second power generation control unit 220 uses the predicted optimal power generation voltage Vopt to perform power generation control of the perovskite solar cell 120.

[0050] In step S60, the control unit 200 determines whether to continue power generation from the series-connected solar cell 100. If power generation continues, the process returns from S60 to S10 and repeats the subsequent steps. Conversely, if power generation ceases, the process ends. Figure 5 The processing.

[0051] As described above, in the first embodiment, information IG1 related to the PV curve G1 of the silicon solar cell 110 is used to predict the optimal power generation voltage Vopt suitable for the perovskite solar cell 120. Therefore, compared to scanning the power generation of the perovskite solar cell 120, efficient power generation control can be performed in a short time.

[0052] B. Second Implementation Method

[0053] Figure 6 This is a flowchart of the power generation control of the series-connected solar cell 100 in the second embodiment. The power generation control in the second embodiment... Figure 5 The power generation control in the first embodiment shown includes steps S110 and S120, while the other steps are the same as in the first embodiment. Furthermore, the device configuration in the second embodiment is the same as that in the first embodiment.

[0054] When the PV curve G1 of the silicon solar cell 110 is obtained in S30, in S110, the power generation characteristic prediction unit 230 determines whether the PV curve G1 of the silicon solar cell 110 contains two or more peak power points. If the PV curve G1 contains two or more peak power points, the processing in S40 and S50 is performed in the same way as in the first embodiment. On the other hand, if the PV curve G1 contains only one peak power point, the process proceeds to S120, the second power generation control unit 220 performs MPPT control on the perovskite solar cell 120, and then proceeds to S60.

[0055] Thus, in the second embodiment, when the PV curve G1 of the silicon solar cell 110 has two or more peak power points, the information IG1 related to the PV curve G1 is used to predict the optimal power generation voltage Vopt of the perovskite solar cell 120, and the power generation control of the perovskite solar cell 120 is performed using this optimal power generation voltage Vopt. On the other hand, when the PV curve G1 of the silicon solar cell 110 has only one peak power point, MPPT control is performed on the perovskite solar cell 120. Therefore, efficient power generation control of the perovskite solar cell 120 can be performed based on whether there is local shading in the series-connected solar cell 100.

[0056] Other methods

[0057] This disclosure is not limited to the embodiments described above, and can be implemented in various ways without departing from its spirit. For example, this disclosure can also be implemented in the following aspects. The technical features in the above embodiments corresponding to the technical features in the various aspects described below can be appropriately replaced or combined to solve part or all of the problems of this disclosure, or to achieve part or all of the effects of this disclosure. In addition, if a technical feature is not described as an essential component in this specification, it can be appropriately deleted.

[0058] This disclosure can also be implemented in various ways other than the control method for a series-connected solar cell. For example, it can be implemented in the form of a control system for a series-connected solar cell, a computer program that executes the control method for a series-connected solar cell, or a non-transitory storage medium on which the computer program is recorded.

Claims

1. A control method of a tandem solar cell including a silicon solar cell and a perovskite solar cell, the control method of the tandem solar cell including: obtaining a P-V curve of the silicon solar cell by performing a scan of obtaining a power generation output while varying a power generation voltage of the silicon solar cell every certain period, and performing power generation control of the silicon solar cell at a maximum power point of the P-V curve; predicting an optimum power generation voltage suitable for the perovskite solar cell using information about the P-V curve; and performing power generation control of the perovskite solar cell using the optimum power generation voltage.

2. The control method according to claim 1, the information about the P-V curve including a voltage value of the maximum power point.

3. The control method according to claim 1, the information about the P-V curve including voltage values and power values of one or more peak power points in the P-V curve.

4. The control method according to claim 1, the information about the P-V curve including shape data indicating a shape of the P-V curve.

5. The control method according to claim 1, including: in a case where the P-V curve has two or more peak power points, predicting the optimum power generation voltage suitable for the perovskite solar cell using the information about the P-V curve and performing the power generation control of the perovskite solar cell using the optimum power generation voltage; and in a case where the P-V curve has only one peak power point, performing MPPT control, which is maximum power point tracking control, to the perovskite solar cell.

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