Tandem solar cell control method

Abstract

A technology is provided that can efficiently control the power generation of a tandem solar cell. [Solution] A method for controlling a tandem solar cell includes the steps of: (a) determining the PV curve of a silicon solar cell by periodically scanning the silicon solar cell to determine the power generation power while changing the power generation voltage, and controlling the power generation of the silicon solar cell at the maximum power point of the PV curve; (b) predicting an optimal power generation voltage suitable for a perovskite solar cell using information about the PV curve of the silicon solar cell; and (c) controlling the power generation of the perovskite solar cell using the optimal power generation voltage.

Description

[Technical Field]

[0001] The present disclosure relates to a method for controlling a tandem solar cell. [Background technology]

[0002] Patent Document 1 discloses a solar cell power generation system. Generally, power generation control of silicon solar cells uses a hill-climbing MPPT (Maximum Power Point Tracking) control method. The hill-climbing method is a control method that performs power generation while constantly searching for the maximum power point of the solar cell by current control. However, if the solar cell is in partial shadow (partial shade on the light-receiving surface), multiple peak points occur in the PV curve (power-voltage curve), and the hill-climbing method may not be able to reach the maximum power point among the multiple peak points. Therefore, in power generation control of silicon solar cells, it is common to scan the generated power at a fixed frequency to check whether multiple peak points occur. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-152687 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, tandem solar cells, which include silicon solar cells and perovskite solar cells, have also been used. However, perovskite solar cells have a slower response speed than silicon solar cells, making it difficult to scan the generated power and determine the optimal generated voltage. Therefore, technology that can efficiently control the power generation of tandem solar cells is desired. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a method for controlling a tandem solar cell including silicon solar cells and perovskite solar cells. This control method includes the steps of: (a) periodically scanning the silicon solar cells to determine the power generation power while changing the power generation voltage of the silicon solar cells, thereby obtaining a PV curve for the silicon solar cells, and controlling the power generation of the silicon solar cells at the maximum power point of the PV curve; (b) using information about the PV curve to predict an optimal power generation voltage suitable for the perovskite solar cells; and (c) using the optimal power generation voltage to control the power generation of the perovskite solar cells. This control method uses information about the PV curve of silicon solar cells to predict the optimal power generation voltage suitable for perovskite solar cells, allowing for more efficient power generation control in a shorter time than scanning the power generation power of perovskite solar cells. (2) In the above control method, the information about the PV curve may include a voltage value of the maximum power point. According to this control method, the optimal power generation voltage of a perovskite solar cell can be easily predicted using the voltage value of the maximum power point of a silicon solar cell. (3) In the above control method, the information about the PV curve may include voltage values ​​and power values ​​of one or more peak power points on the PV curve. This control method can accurately predict the optimal power generation voltage of a perovskite solar cell by using the voltage and power values ​​of one or more peak power points in the PV curve of a silicon solar cell. (4) In the above control method, the information about the PV curve may include shape data that represents a shape of the PV curve. This control method makes it possible to accurately predict the optimal power generation voltage of perovskite solar cells using data on the shape of the PV curve of silicon solar cells. (5) The above control method may include a step of performing the steps (b) and (c) when the PV curve has two or more peak power points, and a step of performing MPPT control on the perovskite solar cell when the PV curve has only one peak power point. This control method enables efficient power generation control for perovskite solar cells. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a conceptual diagram of a tandem solar cell according to a first embodiment. [Figure 2] FIG. 1 is a block diagram of a solar cell power generation system according to a first embodiment. [Figure 3] A graph showing the PV curve of a silicon solar cell and the predicted PV curve of a perovskite solar cell in the absence of partial shading. [Figure 4] A graph showing the PV curve of a silicon solar cell and the predicted PV curve of a perovskite solar cell in partial shading. [Figure 5] 4 is a flowchart of power generation control of the tandem solar cell in the first embodiment. [Figure 6] 10 is a flowchart of power generation control of a tandem solar cell in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is a conceptual diagram of a tandem solar cell 100 in a first embodiment. The tandem solar cell 100 has a structure in which silicon solar cells 110 and perovskite solar cells 120 are stacked. The silicon solar cells 110 and the perovskite solar cells 120 each have multiple photoelectric conversion layers. The tandem solar cell 100 is a four-terminal cell in which the silicon solar cells 110 and the perovskite solar cells 120 are not electrically connected. That is, the silicon solar cells 110 have two terminals 112, and the perovskite solar cells 120 also have two terminals 122. The perovskite solar cells 120 mainly absorb short-wavelength light, which is visible light, while the silicon solar cells absorb long-wavelength light, ranging from visible light to infrared light.

[0009] 2 is a block diagram of a solar cell power generation system 300 according to the first embodiment. The solar cell power generation system 300 includes a tandem 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.

[0010] The first power generation control unit 210 executes power generation control of the silicon solar cell 110. Specifically, the first power generation control unit 210 is configured to be able to execute a first process of executing a hill-climbing method of MPPT control on the silicon solar cell 110, and a second process of executing scanning at regular intervals to determine the power generation while changing the power generation voltage, thereby determining the PV curve (power-voltage curve) of the silicon solar cell 110.

[0011] The power generation characteristic prediction unit 230 predicts the PV curve of the perovskite solar cell 120 using information IG1 relating to the PV curve of the silicon solar cell 110, and predicts the optimum power generation voltage Vopt suitable for the perovskite solar cell 120. This will be described later.

[0012] The second power generation control unit 220 executes power generation control of the perovskite solar cell 120. Specifically, the second power generation control unit 220 is configured to be able to execute a first process of executing hill-climbing MPPT control on the perovskite solar cell 120, and a second process of executing 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.

[0013] The power combining unit 240 combines the power generated by the silicon solar cell 110 PW1 obtained under the control of the first power generation control unit 210 and the power generated by the perovskite solar cell 120 PW2 obtained under the control of the second power generation control unit 220, and supplies the combined power to an external load LD.

[0014] 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 realized by a processor executing a computer program stored in memory. 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 may be realized by hardware circuits.

[0015] FIG. 3 is a graph showing the PV curve G1 of the silicon solar cell 110 and the predicted PV curve G2 of the perovskite solar cell 120 in the absence of partial shading. "Partial shading" refers to a state in which a portion of the surface of the tandem solar cell 100 is shaded by an external object such as a cloud, building, or tree. When there is no partial shading and light is shining on the entire surface of the tandem solar cell 100, the PV curve G1 of the silicon solar cell 110 has a mountain-like shape that includes only one peak power point PP1. The predicted PV curve G2 of the perovskite solar cell 120 also has a mountain-like shape that includes only one peak power point PP2.

[0016] FIG. 4 is a graph showing the PV curve G1 of the silicon solar cell 110 and the predicted PV curve G2 of the perovskite solar cell 120 in the presence of partial shading. When there is partial shading, the PV curve G1 of the silicon solar cell 110 takes on a mountain-like shape that includes multiple peak power points PP1_1 and PP1_2. The predicted PV curve G2 of the perovskite solar cell 120 also takes on a mountain-like shape that includes multiple peak power points PP2_1 and PP2_2. Note that the shapes and sizes of the PV curves G1 and G2 vary depending on the number and connection method of the photovoltaic conversion layers, and therefore the PV curves G1 and G2 in FIGS. 3 and 4 are merely examples.

[0017] The shape of the PV curve G1 of the silicon solar cell 110 shown in Figures 3 and 4 can be confirmed by performing scanning to determine the power generation power 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 when irradiated with light than the silicon solar cell 110, so it is difficult to determine the shape of its PV curve G2 in a practical scanning time. Therefore, the power generation characteristic prediction unit 230 predicts an optimal power generation voltage Vopt suitable for the perovskite solar cell 120 using information IG1 related to the PV curve G1 of the silicon solar cell 110, and the second power generation control unit 220 performs power generation control of the perovskite solar cell 120 using this optimal power generation voltage Vopt.

[0018] In the first embodiment, as shown in Fig. 3, even when the PV curve G1 of the silicon solar cell 110 includes only one peak power point PP1, information IG1 related to the PV curve G1 is used to predict an optimum power generation voltage Vopt suitable for the perovskite solar cell 120. However, when the PV curve G1 includes only one peak power point PP1, MPPT control may be performed on the perovskite solar cell 120. This will be described in the second embodiment.

[0019] As the information IG1 regarding the PV curve G1 of the silicon solar cell 110, for example, any of the following can be used. <Information IG1_a> The voltage value of the maximum power point of PV curve G1. <Information IG1_b> Voltage and power values ​​of one or more peak power points PP1 on PV curve G1. <Information IG1_c> Shape data that represents the shape of the PV curve G1. The shape data representing the shape of the PV curve G1 is, for example, one-dimensional data indicating the generated power value for each of a plurality of voltage values ​​set at regular intervals.

[0020] The optimum power generation voltage Vopt of the perovskite solar cell 120 is the voltage corresponding to the maximum power point on the predicted PV curve G2 of the perovskite solar cell 120. The second power generation control unit 220 uses the predicted optimum power generation voltage Vopt to control the power generation of the perovskite solar cell 120. In this way, power generation control can be performed more efficiently and in a shorter time than when scanning the perovskite solar cell 120 for power generation power.

[0021] The prediction function of the power generation characteristics prediction unit 230 may be realized, for example, by a map showing the relationship between information IG1 related to the PV curve G1 and the optimum power generation voltage Vopt, or by a lookup table that receives information IG1 related to the PV curve G1 as an input and outputs the optimum power generation voltage Vopt.Furthermore, the function of the power generation characteristics prediction unit 230 may be realized using a machine learning model that receives information IG1 related to the PV curve G1 as an input and outputs the optimum power generation voltage Vopt.

[0022] 5 is a flowchart of power generation control of the tandem solar cell 100 in the first embodiment. In step S10, the first power generation control unit 210 and the second power generation control unit 220 execute MPPT control on the silicon solar cell 110 and the perovskite solar cell 120, respectively.

[0023] In step S20, the first power generation control unit 210 determines whether it is time to perform scanning of the power generated by the silicon solar cells 110. Scanning of the power generated by the silicon solar cells 110 is performed at regular intervals. The scanning interval is set in advance to, for example, about one minute to several minutes. Furthermore, the time required for one scanning is several seconds to several tens of seconds. If it is not time to perform scanning, the process returns to step S10, and MPPT control of the silicon solar cells 110 and the perovskite solar cells 120 continues. On the other hand, if it is time to perform scanning, the process proceeds from step S20 to step S30.

[0024] In step S30, the first power generation control unit 210 performs scanning of the power generated by the silicon solar cell 110 to obtain the PV curve G1, and controls the power generation of the silicon solar cell 110 at its maximum power point. In the example of Fig. 3, the maximum power point of the silicon solar cell 110 is the only peak power point PP1. In the example of Fig. 4, 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, PP1_2.

[0025] In step S40, the power generation characteristic prediction unit 230 predicts the optimum power generation voltage Vopt of the perovskite solar cell 120 using information IG1 related to the PV curve G1 of the silicon solar cell 110. In step S50, the second power generation control unit 220 executes power generation control of the perovskite solar cell 120 using the predicted optimum power generation voltage Vopt.

[0026] In step S60, the control unit 200 determines whether or not to continue power generation in the tandem solar cell 100. If power generation is to be continued, the process returns from step S60 to step S10, and the processes from step S10 onwards are executed again. On the other hand, if power generation is not to be continued, the process in FIG. 5 ends.

[0027] As described above, in the first embodiment, the optimum power generation voltage Vopt suitable for the perovskite solar cell 120 is predicted using information IG1 related to the PV curve G1 of the silicon solar cell 110, so that power generation control can be performed more efficiently in a shorter time than when scanning the power generation power of the perovskite solar cell 120.

[0028] B. Second embodiment: Fig. 6 is a flowchart of power generation control of the tandem solar cell 100 in the second embodiment. The power generation control in the second embodiment is obtained by adding step S110 and step S120 to the power generation control in the first embodiment shown in Fig. 5, and the other steps are the same as those in the first embodiment. The device configuration in the second embodiment is the same as that in the first embodiment.

[0029] When the PV curve G1 of the silicon solar cell 110 is obtained in step S30, the power generation characteristic prediction unit 230 determines in step S110 whether or not the PV curve G1 of the silicon solar cell 110 includes two or more peak power points. If the PV curve G1 includes two or more peak power points, the processes of steps S40 and S50 are executed, as in the first embodiment. On the other hand, if the PV curve G1 includes only one peak power point, the process proceeds to step S120, where the second power generation control unit 220 executes MPPT control on the perovskite solar cell 120, and then the process proceeds to step S60.

[0030] As described above, 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 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 can be performed on the perovskite solar cell 120 depending on whether or not the tandem solar cell 100 is partially shaded.

[0031] Other forms: The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following aspects. The technical features in the above embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0032] The present disclosure can be realized in various forms other than the control method for a tandem solar cell, such as a control system for a tandem solar cell, a computer program that executes the control method for a tandem solar cell, or a non-transitory storage medium on which a computer program is recorded. [Explanation of symbols]

[0033] 100... tandem solar cell, 110... silicon solar cell, 112... terminal, 120... perovskite solar cell, 122... terminal, 200... control unit, 210... first power generation control unit, 220... second power generation control unit, 230... power generation characteristic prediction unit, 240... power combining unit, 300... solar cell power generation system

Claims

1. A method for controlling a tandem solar cell including a silicon solar cell and a perovskite solar cell, comprising: (a) performing scanning at regular intervals to determine power generation power while changing the power generation voltage of the silicon solar cell, thereby obtaining a PV curve of the silicon solar cell, and performing power generation control of the silicon solar cell at the maximum power point of the PV curve; (b) using information about the PV curve to predict an optimal power generation voltage suitable for the perovskite solar cell; (c) controlling the power generation of the perovskite solar cell using the optimal power generation voltage; A control method comprising:

2. 2. The control method according to claim 1, The control method, wherein the information about the PV curve includes a voltage value of the maximum power point.

3. 2. The control method according to claim 1, The control method, wherein the information about the PV curve includes voltage values ​​and power values ​​of one or more peak power points on the PV curve.

4. 2. The control method according to claim 1, A control method, wherein the information about the PV curve includes shape data representing a shape of the PV curve.

5. 2. The control method according to claim 1, performing steps (b) and (c) if the PV curve has two or more peak power points; performing MPPT control on the perovskite solar cell when the PV curve has only one peak power point; A control method comprising:

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