JP5663740B2 - Solar power plant - Google Patents

Description

  Embodiments described herein relate generally to a tandem solar power generation apparatus.

  A conventional silicon solar cell has a band gap (forbidden band) width of about 1.2 eV, and generates power by receiving light of a long wavelength (red). That is, in the conventional silicon solar cell, since all the wavelength bands of sunlight cannot be used, the power generation efficiency is only 10%.

  Therefore, in order to increase the power generation efficiency, tandem solar cells (multi-junction solar cells) have been proposed. A tandem solar cell is configured by stacking several types of semiconductors having different band gaps so that light from a long wavelength (red) to a short wavelength (blue) can be absorbed. Examples of materials for forming semiconductors having different band gaps include silicon (Si, forbidden band width: 1.2 eV), gallium arsenide (GaAs, forbidden band width: 1.4 eV), and gallium nitride (GaN, forbidden band). Band width: 3.4 eV), germanium (Ge), indium gallium phosphide (InGaP), indium gallium arsenide (InGaAs), and the like. A tandem solar cell can use all wavelengths of sunlight, and thus, for example, about 40%, which is higher in power generation efficiency than a conventional silicon solar cell.

  However, conventional tandem solar cells stack semiconductors with different band gaps, so the lattice constants of each semiconductor layer are matched, a tunnel junction that conducts electricity is provided in the middle, and the power generation (current) of each layer is matched Therefore, it is necessary to control the film thickness. For this reason, the conventional tandem solar cell has many problems in the manufacturing process. Furthermore, when manufacturing a concentrating tandem solar cell that collects light with a lens, it is necessary to match the thermal expansion coefficients of each semiconductor layer and buffer layer (tunnel junction).

  In order to solve these problems in the manufacturing process, a booster circuit is applied, the energy generated by each semiconductor layer is boosted by the booster circuit, and after boosting, the electric power of each semiconductor layer is electrically connected, thereby tandem It is conceivable to manufacture a solar cell. Such a tandem solar cell has the advantage that the use of the booster circuit eliminates the need to control the film thickness so that the power generation amounts (currents) of the respective semiconductor layers coincide with each other, and makes the manufacturing very easy.

  The step-up circuit is a circuit that basically performs step-up by turning on / off a field effect transistor (FET) such as Si. However, in order to operate the FET, a voltage of 1 V or higher is usually required, and in a silicon solar cell (single cell), the output voltage is 1 V or lower, so that the booster circuit cannot be operated.

  Thus, for example, as shown in FIG. 14, a solar cell module has been proposed in which a booster circuit is operated by a solar cell (single cell) using a single pn junction. FIG. 14 is a diagram for explaining a solar cell module for operating the booster circuit.

  As shown in FIG. 14, the solar cell module for operating the booster circuit includes a single cell solar cell 101, a boost DC-DC converter 102, and a start-up converter 103. The step-up DC-DC converter 102 is a DC-DC converter that boosts the output of the single cell solar battery 101 to a voltage at which the device operates or a voltage for charging the battery. The start-up converter 103 is a converter for starting up the step-up DC-DC converter 102. In the configuration illustrated in FIG. 14, the startup converter 103 is provided in order for the step-up DC-DC converter 102 to operate with the energy generated by the single cell solar battery 101.

  That is, it is conceivable that the tandem solar cell can be easily manufactured by adopting the configuration illustrated in FIG. 14 for each semiconductor layer of the tandem solar cell module.

Japanese Patent No. 4223041

Takashi Fuyuki, “Development of High-Efficiency Solar Cell Devices: Current Status and Future Prospects”, IEICE Journal, vol.76, No.10, pp.1097-1102, October 1993 Tatsuya Takagi, “Compound Solar Cell”, Sharp Technical Report, No. 100, pp.28-31, February 2010

  However, in order to manufacture a tandem solar cell by applying a booster circuit, it is necessary to install a booster circuit startup device such as the startup converter 103 illustrated in FIG. 14 for each booster circuit. There was a problem that the number of points increased and the manufacturing cost increased.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a photovoltaic power generation apparatus that can reduce the number of parts and the manufacturing cost. And

  In order to solve the above-described problems and achieve the object, a solar power generation device disclosed in the present application includes a plurality of semiconductor layers in which semiconductor layers having different forbidden bands having a pn junction are stacked via an insulating film, A plurality of step-up power supply devices each having a step-up circuit connected to each of the plurality of semiconductor layers and stepping up an output from the connection-source semiconductor layer. The plurality of semiconductor layers include at least one startable semiconductor layer that is a semiconductor layer having a wide forbidden band that outputs a photovoltaic voltage capable of starting the booster circuit of the booster type power supply device that is the output destination. The plurality of boost type power supply devices are activated such that another boost type power supply device is activated using an output from the boost type power supply device activated by the boost circuit by the photovoltaic voltage output from the startable semiconductor layer. Connected in parallel.

  According to the solar power generation device disclosed in the present application, it is possible to reduce the number of parts and reduce the manufacturing cost.

FIG. 1 is a diagram for explaining a configuration example of the photovoltaic power generation apparatus according to the first embodiment. FIG. 2 is a diagram for explaining a circuit configuration of the step-up power supply device included in the solar power generation device according to the first embodiment illustrated in FIG. 1. FIG. 3 is a diagram (1) for explaining the switch opening / closing control process of the switch control circuit according to the first embodiment. FIG. 4 is a diagram (2) for explaining the switch opening / closing control process of the switch control circuit according to the first embodiment. FIG. 5 is a diagram (3) for explaining the switch opening / closing control process of the switch control circuit according to the first embodiment. FIG. 6 is a flowchart for explaining a switch opening / closing process of the photovoltaic power generation apparatus according to the first embodiment. FIG. 7 is a diagram for explaining switch open / close control processing of the switch control circuit according to the second embodiment. FIG. 8 is a flowchart for explaining switch opening / closing processing of the photovoltaic power generation apparatus according to the second embodiment. FIG. 9 is a diagram for explaining a configuration example of the photovoltaic power generation apparatus according to the third embodiment. FIG. 10 is a diagram (1) for explaining the switch opening / closing control process of the switch control circuit according to the third embodiment. FIG. 11 is a diagram (2) for explaining the switch opening / closing control process of the switch control circuit according to the third embodiment. FIG. 12 is a diagram (3) for explaining the switch opening / closing control process of the switch control circuit according to the third embodiment. FIG. 13 is a flowchart for explaining switch opening / closing processing of the photovoltaic power generation apparatus according to the third embodiment. FIG. 14 is a diagram for explaining a solar cell module for operating the booster circuit.

  Hereinafter, the Example of the solar power generation device which this application discloses is described in detail. In addition, this invention is not limited by the following examples.

  The solar power generation device according to the first embodiment includes a plurality of semiconductor layers in which semiconductor layers having pn junctions and different forbidden bands (band gaps) are stacked via an insulating film. The solar power generation apparatus according to the first embodiment includes a plurality of boost type power supply devices that are connected to each of the plurality of semiconductor layers and have a booster circuit that boosts the output from the connection source semiconductor layer. That is, the solar power generation device according to Example 1 is a tandem solar cell to which a booster circuit is applied.

  In the photovoltaic power generation apparatus according to the first embodiment, a semiconductor with a wide forbidden bandwidth (wide band gap) in which a plurality of semiconductor layers outputs a photovoltaic voltage capable of starting up a booster circuit of a booster type power supply device as an output destination. It has at least one startable semiconductor layer which is a layer. In the photovoltaic power generation apparatus according to the first embodiment, a plurality of booster type power supply devices use the output from the booster type power supply device in which the booster circuit is activated by the photovoltaic voltage output from the startable semiconductor layer. The boost type power supply devices are connected in parallel so as to start up.

  Hereinafter, a specific configuration example of the photovoltaic power generation apparatus according to the first embodiment will be described with reference to FIG. FIG. 1 is a diagram for explaining a configuration example of the photovoltaic power generation apparatus according to the first embodiment.

  As shown in FIG. 1, the photovoltaic power generation apparatus according to Example 1 includes, as three semiconductor layers, a first semiconductor layer 1 having a pn junction, a second semiconductor layer 3 having a pn junction, and a pn And a third semiconductor layer 5 having a junction. As shown in FIG. 1, a first insulating film 2 is stacked on the first semiconductor layer 1, and a second semiconductor layer 3 is stacked on the first insulating film 2. The Further, a second insulating film 4 is stacked on the second semiconductor layer 3, a third semiconductor layer 5 is stacked on the second insulating film 4, and a third semiconductor layer 5 is stacked. On top of this, a third insulating film 6 is laminated. The first insulating film 2, the second insulating film 4, and the third insulating film 6 are made of a material that can transmit visible light and can be insulated.

  Here, the first semiconductor layer 1 illustrated in FIG. 1 is germanium (Ge), the second semiconductor layer 3 illustrated in FIG. 1 is silicon (Si), and the third semiconductor layer illustrated in FIG. The semiconductor layer 5 is gallium arsenide (GaAs). That is, the photovoltaic power generation apparatus according to Example 1 illustrated in FIG. 1 has three semiconductor layers in which semiconductor layers having different band gaps having a pn junction are stacked via an insulating film. In the photovoltaic power generation apparatus according to Example 1 illustrated in FIG. 1, a third semiconductor layer is formed of gallium arsenide, which is a wide-hand gap material for short wavelengths, as one of the three semiconductor layers. The semiconductor layer 5 is selected.

  In addition, the plurality of semiconductor layers included in the solar power generation device according to Example 1 are solar cells including one pn junction. That is, the first semiconductor layer 1, the second semiconductor layer 3, and the third semiconductor layer 5 included in the photovoltaic power generation apparatus according to Example 1 illustrated in FIG. 1 are single cells made of one pn junction. is there.

  In the photovoltaic power generation apparatus according to Example 1 illustrated in FIG. 1, the first step-up power supply device 7 is connected to the first semiconductor layer 1, and the second step-up power supply is connected to the second semiconductor layer 3. The device 8 is connected, and the third boost type power supply device 9 is connected to the third semiconductor layer 5.

  Here, the first boosting power supply device 7, the second boosting power supply device 8, and the third boosting power supply device 9 have the same circuit configuration. Therefore, the circuit configuration of the third step-up power supply device 9 will be described with reference to FIG. FIG. 2 is a diagram for explaining a circuit configuration of the step-up power supply device included in the solar power generation device according to the first embodiment illustrated in FIG. 1.

  As shown in FIG. 2, the third step-up power supply device 9 receives the power generated by the third semiconductor layer 5 as an input, and the load connected to the output side can use the voltage of the input power. It is a device that boosts the voltage. Therefore, as shown in FIG. 2, the third boost type power supply device 9 includes a boost control circuit 9a and a field effect transistor (FET) 9b. The step-up control circuit 9a controls the open / close time of the FET 9b so that a voltage (for example, 12V) for operating the load is output from the FET 9a. The FET 9b requires a voltage of 1 V or more in order to operate.

  Here, since the forbidden bandwidth is 1.4 eV, the third semiconductor layer 5 is a startable semiconductor layer that outputs a photovoltaic voltage that can start the FET 9b. Therefore, when the third semiconductor layer 5 starts to generate power by sunshine, the boost control circuit 9a receives the power output from the third semiconductor layer 5 from the output terminal side and supplies it to the FET 9b. Since the output voltage from the layer 5 is 1V or more, the FET 9b starts to operate, and as a result, the third boost type power supply device 9 can be activated. As a result, the third step-up power supply device 9 outputs a voltage of 12V, for example.

  Then, by supplying the output from the third boost type power supply device 9 to each of the boost control circuits included in the first boost type power supply device 7 and the second boost type power supply device 8, the first boost type power supply is provided. The device 7 and the second boost type power supply device 8 can be activated. That is, the solar power generation device according to the first embodiment has the boost type power supply device 7 even if the output voltages of the first semiconductor layer 1 and the second semiconductor layer 3 are 0.5 V, 0.8 V, and 1 V or less. In addition, the step-up power supply device 8 can be activated.

  Therefore, in the photovoltaic power generation apparatus according to the first embodiment, the first boost power supply device 7, the second boost power supply device 8, and the third boost power supply device 9 are output from the third semiconductor layer 5. The first booster power supply device 7 and the second booster power supply device 8 are connected in parallel using the output from the third booster power supply device 9 activated by the photovoltaic voltage. Is done.

  Specifically, the photovoltaic power generation apparatus according to the first embodiment includes a switch provided on each wiring that connects the boosting power supply device connected to the startable semiconductor layer and each of the other boosting power supply devices in parallel. Have a group. For example, in the solar power generation device according to the first embodiment, as shown in FIG. 1, the output side of the third boost type power supply device 9 and the output side of the first boost type power supply device 7 are the first switch 10. Connected through. Further, as shown in FIG. 1, in the photovoltaic power generation apparatus according to Example 1, the output side of the third boost type power supply device 9 and the output side of the second boost type power supply device 8 are the second switches 11. Connected through.

  In the solar power generation device according to the first embodiment, after the booster circuit of the booster power supply device connected to the startable semiconductor layer is started, the output of the booster power supply device that has started the booster circuit is another booster power supply. The switch group is controlled to be supplied to the apparatus. Specifically, the photovoltaic power generation apparatus according to Example 1 opens the switch group in the initial state, and after detecting the output from the booster type power supply device connected to the startable semiconductor layer, the switch group is bundled. Close. And the solar power generation device which concerns on Example 1 is controlled to open | release a switch group collectively, after detecting the output from all the other pressure | voltage rise type power supply devices. In order to perform such switch opening / closing control, the photovoltaic power generation apparatus according to the first embodiment includes, as illustrated in FIG. 1, the first boost type power supply apparatus 7, the second boost type power supply apparatus 8, and the third boost type. A switch control circuit 12 is connected to the output side of each power supply device 9.

  Hereinafter, switch opening / closing control of the switch control circuit 12 included in the photovoltaic power generation apparatus according to Embodiment 1 illustrated in FIG. 1 will be described with reference to FIGS. 3 to 5 are diagrams for explaining switch opening / closing control processing of the switch control circuit according to the first embodiment.

  First, as illustrated in FIG. 3, the switch control circuit 12 included in the photovoltaic power generation apparatus according to the first embodiment illustrated in FIG. 1 includes the first switch 10 in an initial state such as when the photovoltaic power generation apparatus starts operation. And the second switch 11 is opened. Then, the switch control circuit 12 detects the output from the third step-up power supply device 9 connected to the third semiconductor layer 5 generated by sunshine, and then, as shown in FIG. And the 2nd switch 11 is closed collectively. Then, the switch control circuit 12 detects the outputs from the first boost type power source device 7 and the second boost type power source device 8 based on the output from the third boost type power source device 9, and then, as shown in FIG. In addition, the first switch 10 and the second switch 11 are collectively opened.

  That is, the boosting power supply device 7 and the boosting power supply device 8 whose booster circuit is started up by the output from the third boosting power supply device 9 that is started up independently are connected to the first semiconductor layer 1 and A voltage sufficient to operate the FET of its own device with the power generated by the second semiconductor layer 3 can be obtained. Therefore, each of the boost type power supply device 7 and the boost type power supply device 8 can be independent. Therefore, each of the boosting power supply device 7 and the boosting power supply device 8 does not need to receive power from the boosting power supply device 9 after startup, and the switch control circuit 12 includes the first switch 10 and the second switch Disconnect the switch 11.

  Then, the procedure of the switch opening / closing process of the solar power generation device according to the first embodiment will be described with reference to FIG. FIG. 6 is a flowchart for explaining a switch opening / closing process of the photovoltaic power generation apparatus according to the first embodiment.

  As illustrated in FIG. 6, the photovoltaic power generation apparatus according to the first embodiment determines whether or not the operation of the own apparatus has been started (step S <b> 101). For example, the switch control circuit 12 included in the photovoltaic power generation apparatus according to the first embodiment determines whether or not the administrator has received a start request for the switch opening / closing process. Here, when the operation is not started (No at Step S101), the switch control circuit 12 is in a standby state.

  On the other hand, when the operation is started (Yes at Step S101), the switch control circuit 12 opens all the switches (the first switch 10 and the second switch 11) (Step S102). Then, the switch control circuit 12 determines whether or not the output of the third step-up power supply device 9 has been detected (step S103). Here, when the output of the third step-up power supply device 9 is not detected (No at Step S103), the switch control circuit 12 enters a standby state.

  On the other hand, when the output of the third boost type power supply device 9 is detected (Yes at Step S103), the switch control circuit 12 closes all the switches (Step S104), and the first boost type power supply device 7 and the second boost type power supply device are closed. It is determined whether or not the output of the mold power supply device 8 has been detected (step S105). Here, when the outputs of the first step-up power supply device 7 and the second step-up power supply device 8 are not detected (No at Step S105), the switch control circuit 12 enters a standby state.

  On the other hand, when the outputs of the first boost type power supply device 7 and the second boost type power supply device 8 are detected (Yes at Step S105), the switch control circuit 12 opens all the switches (Step S106) and ends the processing. To do.

  As described above, in the first embodiment, a plurality of semiconductor layers each having a pn junction and having different forbidden bands are stacked with an insulating film interposed therebetween, so that the booster circuit of the booster power supply device that is the output destination can be activated. It has at least one startable semiconductor layer which is a semiconductor layer with a wide forbidden bandwidth that outputs a photovoltaic voltage. In addition, a plurality of booster type power supply devices having a booster circuit that is connected to each of a plurality of semiconductor layers and boosts an output from the connection source semiconductor layer, the booster circuit is started by the photovoltaic voltage output from the startable semiconductor layer The other boost type power supply devices are connected in parallel using the output from the boost type power supply device.

  In a tandem solar cell, a semiconductor element (solar cell) having a large forbidden band (a large output voltage) is necessarily mounted in order to increase power generation efficiency. That is, in Example 1, a semiconductor layer formed by such a semiconductor element is a startable semiconductor layer, and all boosting power supply devices can be started by starting the booster circuit with the output voltage of the startable semiconductor layer. Therefore, in the first embodiment, there is no need to install a booster circuit starting device such as a converter for starting the booster circuit, and the number of parts can be reduced and the manufacturing cost can be reduced. In addition, since the number of parts can be reduced, it is possible to increase the reliability in manufacturing the tandem solar power generation apparatus.

  In the first embodiment, the switch group is provided on each wiring that connects the boosting power supply device connected to the startable semiconductor layer and each of the other boosting power supply devices in parallel. In addition, the switch control circuit 12 supplies the output of the booster power supply device whose booster circuit has been started to another booster power supply device after the booster circuit of the booster power supply device connected to the startable semiconductor layer is started. The switch group is controlled as follows. Specifically, the switch control circuit 12 opens the switch group in the initial state, detects the output from the boost type power supply device connected to the startable semiconductor layer, and then closes the switch group all at once. After detecting the outputs from all of the boost type power supply devices, the switch group is opened at once.

  In other words, according to the first embodiment, the start-up control of the first boost power supply device 7 and the second boost power supply device 8 using the output of the third boost power supply device 9 is performed for the switch group in a lump. It can be done by closing. In addition, after the first boost type power supply device 7 and the second boost type power supply device 8 are activated, the output supply from the third boost type power supply device 9 becomes unnecessary, so the switch group is closed at once. . Therefore, according to the first embodiment, since the switch opening / closing control can be executed simply, the number of parts required for manufacturing the switch control circuit 12 can be reduced, and the manufacturing cost can be further reduced. .

  In Example 1, the plurality of semiconductor layers are configured as a solar cell including one pn junction. For example, a silicon semiconductor element can generate only a voltage of about 0.55 V in actual use, but the voltage increases by connecting a plurality of elements in series, so it is not necessary to provide a wide band gap semiconductor layer. . However, in a tandem solar cell, connecting semiconductor elements in series within the same plane is expensive and unrealistic, and only a single cell can be produced by a normal manufacturing process. Therefore, in this embodiment, it is necessary that a plurality of semiconductor layers (the first semiconductor layer 1, the second semiconductor layer 3, and the third semiconductor layer 5) are constituted by a single cell.

  In the above description, the case where the switch control circuit 12 that detects the output from the third boost type power supply device 9 closes the first switch 10 and the second switch 11 has been described. However, in this embodiment, the first switch 10 and the second switch 11 are FETs, and the first switch 10 and the second switch 11 are automatically turned on by the output from the third step-up power supply device 9. It may be configured to be closed.

  In the second embodiment, a case where switch opening / closing control is performed by a method different from that of the first embodiment will be described.

  The solar power generation device according to the second embodiment is configured in the same manner as the solar power generation device according to the first embodiment described with reference to FIG. 1, but the processing of the switch control circuit 12 is different from that of the first embodiment. Hereinafter, this will be mainly described.

  Similar to the first embodiment, the switch control circuit 12 according to the second embodiment opens the switch group in the initial state. Unlike the first embodiment, the switch control circuit 12 according to the second embodiment closes one switch in the switch group after detecting the output from the boost type power supply device connected to the startable semiconductor layer. The switch is opened after an output from the boost power supply connected to the boost power supply connected to the startable semiconductor layer is detected by closing the switch. The switch control circuit 12 according to the second embodiment sequentially performs the switch opening / closing control process in each switch constituting the switch group.

  Hereinafter, the case where the switch control circuit 12 according to the second embodiment performs the above-described process on the solar power generation device illustrated in FIG. 1 will be described with reference to FIG. FIG. 7 is a diagram for explaining switch open / close control processing of the switch control circuit according to the second embodiment.

  First, similarly to the first embodiment, the switch control circuit 12 according to the second embodiment opens the first switch 10 and the second switch 11 in the initial state (see FIG. 3). Then, the switch control circuit 12 according to the second embodiment, for example, in FIG. 7A after the startup of the third boost type power supply device 9 connected to the third semiconductor layer 5 which is the startable semiconductor layer. As shown, the first switch 10 is closed.

  Then, the switch control circuit 12 according to the second embodiment closes the first switch 10 to activate the first booster power supply device 7 connected to the third booster power supply device 9, and As shown in B), the first switch 10 is opened. Then, the switch control circuit 12 according to the second embodiment closes the second switch 11 as illustrated in FIG.

  Then, the switch control circuit 12 according to the second embodiment closes the second switch 11 to activate the second switch after the second boost power supply 8 connected to the third boost power supply 9 is activated. 11 is released. As a result, all the switch groups (the first switch 10 and the second switch 11) are opened (see FIG. 5).

  In addition, the order of the switches on which the open / close control is performed is set in advance, for example, by the administrator of the photovoltaic power generation apparatus.

  Then, the procedure of the switch opening / closing process of the solar power generation device concerning Example 2 is demonstrated using FIG. FIG. 8 is a flowchart for explaining switch opening / closing processing of the photovoltaic power generation apparatus according to the second embodiment.

  As illustrated in FIG. 8, the photovoltaic power generation apparatus according to the second embodiment determines whether or not the operation of the own apparatus has been started (step S <b> 201). Here, when the operation has not been started (No at Step S201), the switch control circuit 12 enters a standby state.

  On the other hand, when the operation is started (Yes at Step S201), the switch control circuit 12 opens all the switches (the first switch 10 and the second switch 11) (Step S202). Then, the switch control circuit 12 determines whether or not the output of the third step-up power supply device 9 has been detected (step S203). Here, when the output of the third step-up power supply device 9 is not detected (No at Step S203), the switch control circuit 12 enters a standby state.

  On the other hand, when the output of the third boost type power supply device 9 is detected (Yes at Step S203), the switch control circuit 12 closes the first switch 10 (Step S204), and the output of the first boost type power supply device 7 is reached. Is detected (step S205). Here, when the output of the first step-up power supply device 7 is not detected (No at Step S205), the switch control circuit 12 enters a standby state.

  On the other hand, when the output of the first step-up power supply device 7 is detected (Yes at Step S205), the switch control circuit 12 opens the first switch 10 (Step S206), and further closes the second switch 11. (Step S207). Then, the switch control circuit 12 determines whether or not the output of the second booster type power supply device 8 has been detected (step S208). Here, when the output of the second step-up power supply device 8 is not detected (No at Step S208), the switch control circuit 12 enters a standby state.

  On the other hand, when the output of the second step-up power supply device 8 is detected (Yes at Step S208), the switch control circuit 12 opens the second switch 11 (Step S209) and ends the process.

  As described above, according to the second embodiment, the switch control circuit 12 opens the switch group in the initial state, and after detecting the output from the step-up power supply device connected to the startable semiconductor layer, The switch is opened and closed after the output from the boost power supply connected to the boost power supply connected to the startable semiconductor layer is detected by closing one of the switches and closing the switch. Control processing is sequentially performed in each switch constituting the switch group.

  Here, in the switch opening / closing control processing of the first and second embodiments, first, the boost type power supply device connected to the semiconductor layer (third semiconductor layer 5) having a large band gap (high output voltage) is activated. After that, the booster type power supply device that has not been activated and the output voltage of the semiconductor element is small is activated. However, in the method according to the first embodiment in which the switch groups are opened and closed at once, when the generated power of the first boost type power supply device is small (for example, when the morning sun begins to enter or when the rain stops and it becomes bright) Etc.) may fail to start due to voltage drooping in the operation of other boost type power supply devices. In such a case, the switch group needs to be turned on and off many times. In the switch open / close control process of the first embodiment, there is no problem because all the boost type power supply devices are activated, but the generated power cannot be taken out as much as it cannot be activated smoothly, and the generated power amount is negative.

  On the other hand, in the method of the second embodiment, since the switches are turned on and off one by one in sequence, the processing of the switch control circuit 12 is complicated, but even when the generated power of the boost type power supply device that is activated first is small, all of the switches are smoothly performed. The boost type power supply can be activated. As a result, in Embodiment 2, it is possible to avoid a decrease in the amount of generated power.

  In the above description, the case where the other boost power supply devices are started one by one using the output of the boost power supply device connected to the startable semiconductor layer has been described. However, in the second embodiment, another boost type power supply device is grouped into one or a plurality of devices, and the output of the boost type power supply device connected to the startable semiconductor layer is used to configure another boost type power supply device. It is also possible to start up in groups.

  In the third embodiment, a case will be described in which a plurality of step-up power supply devices are connected in parallel in a form different from the first and second embodiments.

  Similar to the first and second embodiments, the photovoltaic power generation apparatus according to the third embodiment includes a plurality of semiconductor layers in which semiconductor layers with different forbidden bands having a pn junction are stacked via an insulating film. Here, like the first and second embodiments, the plurality of semiconductor layers have at least one startable semiconductor layer. Further, the solar power generation device according to the third embodiment includes a plurality of boost type power supply devices each having a booster circuit that boosts the output from the connection source semiconductor layer, as in the first and second embodiments. The plurality of boost type power supply devices are connected in parallel so that other boost type power supply devices can be started up using the output from the boost type power supply device started up by the booster circuit by the photovoltaic voltage output from the startable semiconductor layer. Although connected, the connection form is different from those in the first and second embodiments.

  Hereinafter, a specific configuration example of the photovoltaic power generation apparatus according to Embodiment 3 will be described with reference to FIG. FIG. 9 is a diagram for explaining a configuration example of the photovoltaic power generation apparatus according to the third embodiment.

  As shown in FIG. 9, the photovoltaic power generation apparatus according to Example 3 includes, as three semiconductor layers, a fourth semiconductor layer 21 having a pn junction, a fifth semiconductor layer 23 having a pn junction, and pn And a sixth semiconductor layer 25 having a junction. As shown in FIG. 1, a fourth insulating film 22 is stacked on the fourth semiconductor layer 21, and a fifth semiconductor layer 23 is stacked on the fourth insulating film 22. The Further, a fifth insulating film 24 is stacked on the fifth semiconductor layer 23, a sixth semiconductor layer 25 is stacked on the fifth insulating film 24, and a sixth semiconductor layer 25 is stacked. On the top, a sixth insulating film 26 is laminated. The fourth insulating film 22, the fifth insulating film 24 and the sixth insulating film 26 are visible light similarly to the first insulating film 2, the second insulating film 4 and the third insulating film 6. It is made of a material that can pass through and can be insulated.

  Here, the fourth semiconductor layer 21 illustrated in FIG. 9 is germanium (Ge), and the fifth semiconductor layer 23 illustrated in FIG. 9 is silicon (Si), and the sixth semiconductor layer illustrated in FIG. The semiconductor layer 25 is gallium arsenide (GaAs). That is, the photovoltaic power generation apparatus according to Example 3 illustrated in FIG. 9 has a three-layer structure in which each semiconductor layer having a pn junction and having different band gaps is stacked via an insulating film, as in Examples 1 and 2. A semiconductor layer; In the photovoltaic power generation apparatus according to Example 3 illustrated in FIG. 9, the sixth semiconductor layer formed of gallium arsenide, which is a short-wave wide-hand gap material, is used as one of the three semiconductor layers. The semiconductor layer 25 is selected.

  Further, the plurality of semiconductor layers included in the solar power generation device according to the third embodiment are solar cells including one pn junction as in the first and second embodiments. That is, the fourth semiconductor layer 21, the fifth semiconductor layer 23, and the sixth semiconductor layer 25 included in the photovoltaic power generation apparatus according to Example 3 illustrated in FIG. 9 are a single cell composed of one pn junction. is there.

  In the photovoltaic power generation apparatus according to Example 3 illustrated in FIG. 9, the fourth step-up power supply device 27 is connected to the fourth semiconductor layer 21, and the fifth step-up power supply is connected to the fifth semiconductor layer 23. The device 28 is connected, and the sixth step-up power supply device 29 is connected to the sixth semiconductor layer 25.

  The fourth boosting power supply device 27, the fifth boosting power supply device 28, and the sixth boosting power supply device 29 have the same circuit configuration as that of the third boosting power supply device 9 described with reference to FIG. Circuit configuration.

  That is, the sixth boosting power supply device 29 can be activated by operating the boosting circuit by the output from the sixth semiconductor layer 25, and the fourth boosting power supply device 27 and the fifth boosting power supply device. 28 can be activated by the output from the sixth step-up power supply 29.

  In the first and second embodiments, the description has been given of the case where another boosting power supply device is started by the output from the boosting power supply device started by the output from the startable semiconductor layer. However, the boost type power supply device used for starting other boost type power supply devices is not necessarily a boost type power supply device connected to the startable semiconductor layer. For example, it is possible to start the fifth boosting power supply device 28 by using the fourth boosting power supply device 27 started by the output from the sixth boosting power supply device 29.

  Therefore, the photovoltaic power generation apparatus according to the third embodiment includes a boosting power supply device connected to the startable semiconductor layer and a wiring that connects one boosting power supply device among other boosting power supply devices in parallel. And a switch group provided on wiring for connecting other boost type power supply devices in parallel. For example, as illustrated in FIG. 9, in the solar power generation device according to the third embodiment, the third switch 30 includes an output side of the sixth boost type power supply device 29 and an output side of the fourth boost type power supply device 27. Connected through. Further, in the photovoltaic power generation apparatus according to Example 3, as shown in FIG. 9, the output side of the fourth boost type power supply device 27 and the output side of the fifth boost type power supply device 28 are the fourth switches 31. Connected through.

  And the solar power generation device which concerns on Example 3 has the switch control circuit 32 illustrated in FIG. 9, in order to control a switch group. First, similarly to the switch control circuit 12, the switch control circuit 32 opens the switch group in the initial state. Then, the switch control circuit 32 detects the output from the step-up power supply device connected to the startable semiconductor layer, then closes the switch on the output side of the step-up power supply device that detected the output, and closes the switch. Thus, after the output from the boosting power supply device connected to the boosting power supply device that has already started the booster circuit is detected, the switch is opened. With the above processing, one boosting power supply device among other boosting power supply devices is activated by the output from the boosting power supply device connected to the startable semiconductor layer.

  Then, the switch control circuit 32 further closes a switch on the output side of the booster type power supply device in which the booster circuit has been activated among other booster type power supply devices, and closes the switch so that the booster type in which the booster circuit has been activated. After the output from the boost type power supply device connected to the power supply device is detected, the switch is opened. The switch control circuit 32 sequentially performs such switch open / close control processing on switches provided on wirings that connect other boost type power supply devices in parallel. As a result, the switch control circuit 32 can start up all the remaining boost type power supply devices using a boost type power supply device other than the boost type power supply device connected to the startable semiconductor layer.

  Hereinafter, the case where the switch control circuit 32 according to the third embodiment executes the above-described processing for the solar power generation device illustrated in FIG. 9 will be described with reference to FIGS. 10 to 12 are diagrams for explaining the switch open / close control processing of the switch control circuit according to the third embodiment.

  First, as illustrated in FIG. 10, the switch control circuit 32 included in the photovoltaic power generation apparatus according to the third embodiment illustrated in FIG. 9 includes the third switch 30 in an initial state such as when the photovoltaic power generation apparatus starts operation. And the fourth switch 31 is opened. Then, the switch control circuit 32 detects the output from the sixth step-up power supply device 29 connected to the sixth semiconductor layer 25 generated by sunshine, and then outputs the output as shown in FIG. The third switch 30 on the output side of the sixth step-up power supply device 29 that has detected is closed.

  Then, the switch control circuit 32 closes the third switch 30 to detect the output from the third boosting power supply device 27 connected to the sixth boosting power supply device 29 that has already started the boosting circuit. As shown in FIG. 11B, the third switch 30 is opened.

  Further, as shown in FIG. 11B, the switch control circuit 32 is a booster whose booster circuit has already been activated in another booster power supply device (a booster power supply device other than the sixth booster power supply device 29). The fourth switch 31 on the output side of the third step-up power supply device 27 that is the type power supply device is closed. Then, the switch control circuit 32 closes the fourth switch 31 from the fourth step-up power supply device 28 connected to the third step-up power supply device 27 which is the step-up power supply device that has been started up the step-up circuit. After the output is detected, the fourth switch 31 is opened as shown in FIG.

  Then, the procedure of the switch opening / closing process of the solar power generation device concerning Example 3 is demonstrated using FIG. FIG. 13 is a flowchart for explaining switch opening / closing processing of the photovoltaic power generation apparatus according to the third embodiment.

  As illustrated in FIG. 13, the photovoltaic power generation apparatus according to the third embodiment determines whether or not the operation of the own apparatus has been started (step S <b> 301). Here, when the operation is not started (No at Step S301), the switch control circuit 32 is in a standby state.

  On the other hand, when the operation is started (Yes at Step S301), the switch control circuit 32 opens all the switches (the third switch 30 and the fourth switch 31) (Step S302). Then, the switch control circuit 32 determines whether or not the output of the sixth step-up power supply device 29 has been detected (step S303). Here, when the output of the sixth step-up power supply device 29 is not detected (No at Step S303), the switch control circuit 32 enters a standby state.

  On the other hand, when the output of the sixth step-up power supply device 29 is detected (Yes at Step S303), the switch control circuit 32 closes the third switch 30 (Step S304), and the output of the fourth step-up power supply device 27. Is detected (step S305). Here, when the output of the fourth step-up power supply device 27 is not detected (No at Step S305), the switch control circuit 32 enters a standby state.

  On the other hand, when the output of the fourth step-up power supply device 27 is detected (Yes at Step S305), the switch control circuit 32 opens the third switch 30 (Step S306), and further closes the fourth switch 31. (Step S307). Then, the switch control circuit 32 determines whether or not the output of the fifth step-up power supply device 28 has been detected (step S308). Here, when the output of the fifth step-up power supply device 28 is not detected (No at Step S308), the switch control circuit 32 enters a standby state.

  On the other hand, when the output of the fifth step-up power supply device 28 is detected (Yes at Step S308), the switch control circuit 32 opens the fourth switch 31 (Step S309), and ends the process.

  As described above, according to the third embodiment, the switch group connects in parallel the boost type power supply device connected to the startable semiconductor layer and one boost type power supply device among the other boost type power supply devices. It is provided on the wiring and on the wiring that connects the other boost type power supply devices in parallel. The switch control circuit 32 opens the switch group in the initial state, and after detecting the output from the boost power supply device connected to the startable semiconductor layer, the switch control circuit 32 is on the output side of the boost power supply device that detected the output. The switch is closed, and after the switch is closed, the output from the boosting power supply device connected to the boosting power supply device having the booster circuit activated is detected, and then the switch is opened.

  Further, the switch control circuit 32 closes a switch on the output side of the boosting power source device that has already started the boosting circuit among other boosting power source devices, and closes the switch to thereby boost the power source device that has started the boosting circuit. After the output from the boost type power supply device connected to the switch is detected, the switch opening / closing control processing for opening the switch is sequentially performed on the switches provided on the wiring connecting the other boost type power supply devices in parallel. .

  That is, in the third embodiment, one of the remaining boost type power supply devices is activated by using one boost type power supply device activated by the output of the boost type power supply device connected to the activatable semiconductor layer. Further, in the third embodiment, one of the remaining boosting power supply devices that have not been activated is activated by the output of one activated boosting power supply device. In the third embodiment, this process is performed until all the boost type power supply devices other than the boost type power supply device connected to the startable semiconductor layer are started up.

  Therefore, according to the third embodiment, since the switches are sequentially turned on and off one by one as in the second embodiment, the processing of the switch control circuit 32 becomes complicated, but the generated power of the boost type power supply device that is activated first is Even when it is small, it is possible to smoothly start all the boost type power supply devices, and it is possible to avoid a decrease in the amount of generated power.

  The third embodiment may be a case where the step-up power supply device is activated according to a modification described below. For example, as a modification of the third embodiment, the remaining boost type power supply devices are collectively activated using one boost type power source device activated by the output of the boost type power source device connected to the startable semiconductor layer. In other cases, the remaining boost type power supply devices may be divided into a plurality of groups and activated in groups.

  Further, as a modification of the third embodiment, one boosting power supply device activated by the output of the boosting power supply device connected to the startable semiconductor layer is used, and one of the remaining boosting power supply devices or One or a plurality of boosting power supply devices among the remaining boosting power supply devices that are not started up are activated by starting up the plurality of boosting power supply devices and further, depending on the output of the one or more boosting power supply devices that are started up. May be activated.

  Further, as a modification of the third embodiment, a plurality of other boosting power supply devices are started using the output of the boosting power supply device connected to the startable semiconductor layer, and the plurality of boosting power supply devices that have been started up are activated. The remaining boost type power supply device may be activated in units of devices or in groups using the output. The above-described modification can be executed by changing the wiring for connecting the plurality of booster type power supply devices in parallel, providing a switch on each wiring, and performing switch opening / closing control by the switch control circuit 32.

  By the way, in the first to third embodiments, the case where there is one startable semiconductor layer has been described. However, the above first to third embodiments are applicable even when there are a plurality of startable semiconductor layers.

  Moreover, in above-mentioned Examples 1-3, the case where the semiconductor layer was three layers was demonstrated. However, Examples 1 to 3 described above can be applied even when the semiconductor layer has two layers or four or more layers. However, when manufacturing a solar power generation device that is a tandem solar cell, the number of semiconductor layers is preferably within a predetermined number of layers (for example, three layers).

  Therefore, when the number of semiconductor layers exceeds a predetermined number, at least one of the semiconductor layers exceeding the predetermined number is a startable semiconductor layer, and the number of semiconductors exceeds the predetermined number. The solar power generation devices according to the above-described Examples 1 to 3 are configured so that the boost type power supply device is connected to each layer.

  For example, the solar power generation device illustrated in FIGS. 1 and 9 is used as one module, and a solar power generation device having six semiconductor layers can be manufactured by manufacturing two modules. In the case of manufacturing a solar power generation device having five semiconductor layers, for example, solar power having the solar power generation device illustrated in FIGS. 1 and 9, two semiconductor layers, and two step-up power supply devices. Combine with the generator. For example, a photovoltaic power generation apparatus having two semiconductor layers and two boost type power supply devices includes a second semiconductor layer 3, a second insulating film 4, a third semiconductor layer 5, and a third insulating film 6. It can be manufactured by stacking, connecting the second boost type power supply device 8 to the second semiconductor layer 3, and connecting the third boost type power supply device 9 to the third semiconductor layer 5.

  According to the above modification, as a module unit based on a predetermined number of semiconductor layers, at least one of which is a startable semiconductor layer, by manufacturing a tandem solar power generation device having various layers, It is possible to reduce the number of parts and reduce the manufacturing cost. In addition, since the number of parts can be reduced, it is possible to increase the reliability of manufacturing a tandem solar power generation apparatus having various numbers of layers.

  In addition, among the processes described in the first to third embodiments, all or a part of the processes described as being automatically performed can be manually performed, or can be manually performed. All or part of the described processing can be automatically performed by a known method. In addition, the processing procedure, control procedure, specific name, and information including various data and parameters shown in the above-described document and drawings can be arbitrarily changed unless otherwise specified.

  Further, each component of each illustrated apparatus is functionally conceptual, and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  As described above, the solar power generation device according to the present invention is useful when manufacturing a tandem solar cell, and is particularly suitable for reducing the number of components and reducing the manufacturing cost.

DESCRIPTION OF SYMBOLS 1 1st semiconductor layer 2 1st insulating film 3 2nd semiconductor layer 4 2nd insulating film 5 3rd semiconductor layer 6 3rd insulating film 7 1st pressure | voltage rise type power supply device 8 2nd pressure | voltage rise type Power supply device 9 Third boost type power supply device 9a Boost control circuit 9b Field effect transistor (FET)
10 First switch 11 Second switch 12 Switch control circuit

Claims (7)

a plurality of semiconductor layers in which semiconductor layers having different forbidden band widths, which are forbidden band widths having a pn junction, are stacked via an insulating film;
A plurality of step-up power supply devices each having a step-up circuit connected to each of the plurality of semiconductor layers and stepping up an output from the connecting semiconductor layer;
With
The plurality of semiconductor layers are wide forbidden band width semiconductor layers that output a photovoltaic voltage capable of starting up a booster circuit of a booster type power supply device as an output destination, and have the highest output voltage among the plurality of semiconductor layers. Having at least one activatable semiconductor layer which is a semiconductor layer;
The plurality of step-up power supply devices are connected in parallel so that another step-up power supply device is started using the output from the step-up power supply device started by the step-up circuit by the photovoltaic voltage output from the startable semiconductor layer. Connected,
The step-up power supply device connected to the startable semiconductor layer boosts the photovoltaic voltage output from the startable semiconductor layer and supplies the boosted voltage to a step-up circuit of another step-up power supply device. A featured solar power generator. A switch group provided on each wiring for connecting the boost type power supply device connected to the startable semiconductor layer and each of the other boost type power supply devices in parallel;
After the booster circuit of the booster power supply device connected to the startable semiconductor layer is started, the switch group is set so that the output of the booster power supply device that has started the booster circuit is supplied to the other booster power supply device. A switch control circuit to control;
The solar power generation device according to claim 1, further comprising:   The switch control circuit opens the switch group in an initial state, detects the output from the boost type power supply device connected to the startable semiconductor layer, and then closes the switch group in a batch to 3. The photovoltaic power generation apparatus according to claim 2, wherein the switch group is controlled to be opened collectively after detecting outputs from all the type power supply apparatuses.   The switch control circuit opens the switch group in an initial state, detects an output from a boost type power supply device connected to the startable semiconductor layer, closes one switch in the switch group, and After the output from the boost power supply connected to the boost power supply connected to the startable semiconductor layer by closing the switch is detected, a switch open / close control process for opening the switch is performed on the switch group. The solar power generation device according to claim 2, wherein the solar power generation device is sequentially performed in each of the constituent switches. On the wiring connecting the boosting power supply device connected to the startable semiconductor layer and one boosting power supply device in the other boosting power supply devices in parallel, and between the other boosting power supply devices in parallel A group of switches provided on the wiring connected to
The switch group is opened in an initial state, and after detecting an output from the boost power supply device connected to the startable semiconductor layer, the switch on the output side of the boost power supply device that detected the output is closed, After detecting the output from the boosting power supply device connected to the boosting power supply device whose booster circuit has been activated by closing the switch, the switch is opened, and further the boosting is performed in the other boosting power supply devices. Close the switch on the output side of the boost type power supply device that has started the circuit, and close the switch to detect the output from the boost type power supply device connected to the boost type power source device that has started the boost circuit. A switch control circuit for sequentially performing switch opening / closing control processing for opening the switch in a switch provided on a wiring connecting the other boost type power supply devices in parallel;
The solar power generation device according to claim 1, further comprising:   When the number of the plurality of semiconductor layers exceeds a predetermined number, at least one of the semiconductor layers whose number exceeds the predetermined number is the startable semiconductor layer, and the number of semiconductors exceeds the predetermined number. The photovoltaic power generation apparatus according to any one of claims 1 to 5, wherein the step-up power supply apparatus is connected to each layer. Wherein the plurality of semiconductor layers, solar power generation device according to any one of claims 1 to 6, respectively, characterized in that it is configured as a solar cell consisting of one of the pn junction.

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