JP2005115441A - Photovoltaic generation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photovoltaic generation apparatus with high efficiency for easily extending power capacity. <P>SOLUTION: A plurality of DC/DC converters constituted of a boosting chopper circuit are connected to the respective cells of a solar battery. The outputs of the DC/DC converters are connected in parallel. The apparatus includes a control circuit for controlling each DC/DC converter, so as to enable output power from each cell of the solar battery to be the maximum. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a solar power generation device that converts and controls electric power in a configuration in which a DC / DC converter is connected to a cell of a solar cell module constituted by a single solar cell or a plurality of solar cells connected in parallel.

Conventionally, in order to avoid a rapid decrease in generated power due to the influence of a partial shadow of a solar cell module, a configuration in which power is taken out without connecting solar cell element groups constituting the module in series has been proposed. For example, FIGS. 6A and 6B are circuit diagrams showing a conventional device disclosed in Japanese Patent Laid-Open No. 6-22472. In FIGS. 6A and 6B, 38 is connected in series. No solar battery cell, 39 is a booster circuit, 40 is a secondary battery, and 41 is a load.

In this example, as an example of means for obtaining a voltage capable of charging a secondary battery from solar cell elements that are not connected in series, the solar cell element uses amorphous silicon that can be stacked with a photoelectric conversion layer, and the photoelectric conversion layer is The output voltage of the solar cell element is increased by the laminated structure, and then the voltage is boosted to a voltage at which the secondary battery can be charged with an IC booster circuit that can be driven at 1 V to 2 V, which is the output range of the solar cell element. Proposed configuration to do.

Conventionally, a solar cell module in which a power conversion device is attached to the back surface of the solar cell module has been proposed. For example, FIG. 7 is a cross-sectional view of a solar cell module disclosed in Japanese Patent Application Laid-Open No. 2002-141540. In FIG. 7, 42 is a solar cell, 43 is a power converter, and 44 is a back reinforcing material. .

In this example, the power conversion device is attached to the portion of the back surface where the temperature is relatively low for each solar cell module unit, and the heat generated from the solar cells is transmitted to the power conversion device so that the conversion efficiency is not lowered. A proposal has been made.
JP-A-6-22472 JP 2002-141540 A

Since the conventional solar power generation apparatus is configured as described above, in order to obtain the necessary generated power, individual design and manufacturing methods that match the power capacity of the solar cell element and the booster circuit are required. Even when the power capacity is increased in the apparatus, a large design change is required, which is not easy, and there is a problem that it is difficult to standardize the dimensions and characteristics of the solar cell module and the booster circuit.

In a conventional solar power generation device, when using a solar cell using crystalline silicon and a compound semiconductor in which a photoelectric conversion layer cannot be stacked, the open circuit voltage generated by the power generation of the cell is still 0.9 V or less. When the DC / DC converter output voltage is boosted to about 3-5V, which is the normal drive power supply voltage for transistors, etc., the loss during conversion increases as the output power and boosting level increase due to on-resistance during switching. There was a problem to do.

In addition, in a conventional photovoltaic power generation device, in order to convert power of a low output voltage of 0.9 V or less of a solar battery cell using crystalline silicon and a compound semiconductor, in order to stably operate switching of a transistor or the like. However, there is a problem that it cannot function as a solar power generation device when it cannot have a power source in addition to the solar battery cell.

In order to solve the above problem, a photovoltaic power generation apparatus according to claim 1 includes a solar battery cell, a DC / DC converter to which an output of the solar battery cell is input, and a control unit that controls the operation of the DC / DC converter. In the solar power generation apparatus, the DC / DC converter is composed of a plurality of boost chopper circuits, the inputs of the boost chopper circuits are connected in parallel, and the outputs of the boost chopper circuits are parallel. The switching circuit of each boost chopper circuit is shifted and controlled using the control circuit.

In order to solve the above problem, the photovoltaic power generation apparatus according to claim 2 includes a solar battery cell, a DC / DC converter to which an output of the solar battery cell is input, and a control unit that controls the operation of the DC / DC converter. In the solar power generation device, the output of the plurality of solar cells is cut off from being supplied to the DC / DC converter using switch means connected to the outputs of the solar cells, and A storage circuit that temporarily stores the output obtained from the series connection circuit of the solar cells, and when the photovoltaic power generation device is activated, after the output is temporarily stored in the storage circuit, The switching is returned to the connection to the DC / DC converter, and the solar power generation means is operated by driving the DC / DC converter with the electric power obtained from the power storage circuit.

In order to solve the above problem, the solar power generation device according to claim 3 is the solar power generation device according to claim 1 or 2, wherein the DC / DC converter is configured as the power conversion device circuit that performs a switching operation. A starting circuit having a switch that operates by heat or electromagnetic force converted from the output power of a cell, and a driving circuit having an FET as a steady driving switch, and storing the output power of the starting circuit or the driving circuit And a circuit for detecting the level of stored power in the power storage circuit, and the starter circuit and the drive circuit are operated according to the detection level of the circuit for detecting the level of stored power.

According to the invention of claim 1, it is possible to standardize a solar power generation device composed of solar cells and a DC / DC converter, and it is possible to easily add the solar power generation device according to the required power, A solar power generation device capable of outputting large electric power can be easily realized.

In addition, the boost level can be increased from the low output voltage of the solar battery cell, and at the same time, power loss when converting large power can be reduced.

According to the second aspect of the present invention, it is possible to obtain a power source capable of switching to convert power from the output of the solar battery cell without having a power source other than the solar battery cell, and to function the solar power generation device.

According to the invention described in claim 3, it is possible to obtain a circuit for boosting the output of the solar battery cell without having a power source other than the solar battery cell, and to make the solar power generation device function.

Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 shows a solar power generation apparatus used in an embodiment of the present invention, where 1 is a solar battery cell, 2 is a DC / DC converter connected to the output terminal of each solar battery cell 1, and 3 is each solar battery cell. 1 is a control circuit that comprehensively controls the power conversion operation of the DC / DC converter 2 by detecting the output power of the DC / DC converter 2 and the output power of each DC / DC converter 2, and the output terminals of the DC / DC converters are connected in parallel. To do.

The solar cell 1 is the power of the solar cell using crystalline silicon which is generally used, and is about 0.5 V and 10 mW / cm ² at maximum in a good solar radiation condition. The DC / DC converter 2 connected to the circuit is composed of a booster circuit such as a chopper method, a charge pump method, and a switched capacitor method that can boost an input from 0.5 V or less, and performs a switching operation according to a signal from the control circuit 3 Then, power is converted into a predetermined output. The control circuit 3 uses a microcomputer or the like to calculate the generated power of each solar cell from the result of detecting each output voltage and output current of the solar cell 1 that changes greatly under solar radiation conditions. The power for connecting the converter outputs in parallel is determined, and the switching operation of each DC / DC converter is controlled so that the maximum generated power can be obtained as the photovoltaic power generation apparatus. Each solar cell and each DC / DC converter use the same shape and characteristics, and easily respond to the increase in required power by increasing the number of solar cells and DC / DC converters as unit units. It is a device that can. In the above case, the additional unit consisting of the solar cell and the DC / DC converter has the same shape and characteristics, but the characteristics differ by controlling the output of the DC / DC converter by the control circuit. Units can be expanded.

Embodiment 2 of the present invention will be described below with reference to the drawings. FIG. 2 shows a DC / DC converter of a solar power generation apparatus used in an embodiment of the present invention, 4 is a solar battery cell, 5 is a DC / DC converter connected to the output terminal of each solar battery cell 4, 6 Is an inductor of the booster circuit of the DC / DC converter 5, 7 is a switch for performing a switching operation of the booster circuit of the DC / DC converter 5, 8 is a diode constituting the booster circuit of the DC / DC converter 5, and 9 is a booster circuit. Capacitor 10 for detecting the output voltage and output current of the solar battery cell 4, 11 for detecting the signal of the detector 10 and the output voltage from the DC / DC converter 5, and comprehensively switching the switch 7. A plurality of chopper type booster circuits composed of an inductor 6, a switch 7, and a diode 8 are connected in parallel.

The DC / DC converter 5 connected to the solar cell 4 has a structure in which a chopper type booster circuit capable of boosting an input from 0.7 V or less is connected in parallel, and has an ON resistance according to a signal from the control circuit 11. Switching operation is performed by a switch 7 such as a very low MOSFET to convert electric power to a predetermined output. The control circuit 11 uses a microcomputer or the like to calculate the generated power of the solar battery cell from the result of detecting each output of the solar battery cell 4 that changes greatly under solar radiation conditions, and to increase the voltage to a predetermined voltage. The output power of the DC / DC converter 5 is controlled by adjusting the ON / OFF time of the switching operation of a plurality of DC / DC converters connected in parallel, while simultaneously controlling the ON / OFF duty ratio of the switching operation. The chopper type booster circuit connected in parallel can be expanded according to the boost level, and the energy stored in the inductor of each booster circuit can be distributed, and the loss due to the current flowing through each switch 7 can be reduced. Therefore, a DC / DC converter with high conversion efficiency can be obtained.

The third embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows a solar power generation apparatus used in an embodiment of the present invention, where 1 is a solar battery cell, 12 is a DC / DC converter connected to the output terminal of each solar battery cell 1, and 16 and 17 are each solar battery. Switch for switching from series connection of battery cells 1 to connection to each DC / DC converter 12, 18 is a power source for starting and driving the DC / DC converter 12 connected to the solar cells 1 connected in series, 19 is each In addition to detecting the output power of the solar cell 1 and the output power from each DC / DC converter 12 and comprehensively controlling the power conversion operation of the DC / DC converter 12, the solar cells are switched by switching the switches 16 and 17. 1 is connected to each DC / DC converter 12 from a series connection, and is a control circuit for controlling the output of the start-up / drive power supply 18. The output terminal of each DC / DC converter Between it is connected in parallel.

Although the basic structure and operation are the same as those of the first embodiment, each solar cell 1 for starting and driving the DC / DC converter connected to the solar cell 1 is further connected in series to each DC / DC converter 12. Switches 16 and 17 constituted by a reed switch or the like for switching to connection to the power source and a start / drive power source 18 are provided. Since the power of the solar battery cell using crystalline silicon is about 0.7 V and 10 mW / cm ² at maximum in a good solar radiation condition, this drive voltage is used as a power source for driving the DC / DC converter. Connect solar cells in series. For example, when the switches 16 and 17 require a starting / driving voltage of 5 V, about 11 solar cells need to be connected in series. Since the output voltage does not change greatly if there is a small amount of solar radiation as a characteristic of the solar cell, the number of series connections is easily determined when the drive voltage is determined, and the number of switches 16 and 17 is also easily determined. At the time of activation, the control circuit 19 is activated in a state where the solar cells connected to the switches 16 and 17 are connected in series. In the state where the DC / DC converter 12 is driven, the solar cells connected in series are switched to the connection of each DC / DC converter 12. When the DC / DC converter 12 is activated, the electric power necessary for normal driving is obtained, and at the same time, the driving is continuously continued by the electric power obtained from the solar cells. Since the electric power for driving the control circuit is 1/10 or less even when the microcomputer is used as compared with the entire electric power consumption of the electronic device, the number of the solar cells connected in series is the number of the solar cells 1 Very small compared to the total amount.

Embodiment 4 of the present invention will be described below with reference to the drawings. FIG. 4 shows a solar power generation apparatus used in the embodiment of the present invention. In particular, FIG. 4 (b) shows a cross section of FIG. 4 (a). Reference numeral 20 denotes a DC / DC converter, 21 denotes a solar battery cell, and 22 denotes a substrate on which the DC / DC converter 20 and the solar battery cell 21 are mounted and connected by wiring.

The solar battery cell 21 is a solar battery using a commonly used crystalline silicon having an output voltage of 0.5 V or less. The solar cells 21 are arranged at predetermined intervals on a printed circuit board that is electrically wired and electrically connected by soldering or the like, and a DC / DC converter is placed behind the surface that receives solar radiation of each of the arranged solar cells. 20 is fixed, and the input terminal of the DC / DC converter 20 and the output terminal of the solar battery cell are connected via a printed circuit board. Each DC / DC converter 20 is fixed at the same position in the plane of each solar cell, and the output terminal of each solar cell and the input terminal of each DC / DC converter 20 are connected as short as possible.

Embodiment 5 of the present invention will be described below with reference to the drawings. FIG. 5 shows a DC / DC converter of a photovoltaic power generation apparatus used in an embodiment of the present invention, in which 23 is a solar battery cell, 24 is a start circuit, 25 is a switch that performs switching operation by the start circuit 24, and 26 is a switch 25. Switches connected in series, 27 is a switch for a drive circuit, 28 is an inductor of a booster circuit section of a start-up circuit, 29 is a diode connected to the inductor 28, 30 is a capacitor connected to the diode 29, 31 is a start-up / drive circuit , A drive circuit of the DC / DC converter, 33 an inductor of the booster circuit section of the drive circuit, 34 a diode connected to the inductor 33, and 35 connected to the solar cell 23, and a starting circuit 24 and a switch for switching between the driving circuit 32 and a detector 36 for detecting the output voltage and output current of the solar battery cell 23 37 switching operation of the switch 26 and the switch 27, switching of the switch 35, detects the output power of the signal of the detector 36 and the DC / DC converter, a control circuit for comprehensively controlling the switching operation of the switch 27.

The DC / DC converter connected to the solar battery cell 23 includes a drive circuit 32 and a starter circuit 24 for driving the drive circuit 32. The power of the solar cell using crystalline silicon is about 0.7 V and 10 mW / cm ² at maximum in a good solar radiation condition. Therefore, to drive the DC / DC converter, the power of the solar cell up to the drive voltage is required. A start-up circuit that boosts the output voltage is required. The start circuit 24 is a chopper type booster circuit, the switch 26 for starting is turned on in the initial state, and the switch 25 is turned on / off. The thermoswitch operates with heat generated by the current flowing through the switch 25 and is activated using the power of the solar battery cell 23. The initial state of the switch 25 is ON, and the current output from the solar battery cell 23 due to solar radiation flows to the thermo switch, and heat is generated by the resistance of the thermo switch, and the switch 25 is turned OFF. The thermo switch that is turned off is turned on again when current stops flowing and the temperature drops. This operation is periodically repeated, and the boosted power is stored in the capacitor 30 and the power storage circuit 31, and the DC / DC converter is driven. At the same time as the DC / DC converter is driven, the switch 35 switches the output of the solar cell from the startup circuit to the drive circuit, the switch 26 is turned OFF from the initial state, the switching operation of the switch 25 is stopped, and the switch 27 is the control circuit. 37 starts the switching operation constantly. In addition, the switch 27 that performs the switching operation of the drive circuit as compared with the switch 26 and the switch 35 uses an FET having excellent durability and extremely low ON resistance.

1 is a first embodiment of the present invention. It is the 2nd Embodiment of this invention. It is the 3rd Embodiment of this invention. It is the 4th Embodiment of this invention. It is the 5th Embodiment of this invention. It is the circuit of the conventional solar power generation device. It is the structure of the conventional solar power generation device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar cell 2 DC / DC converter 3 Control circuit 4 Solar cell 5 DC / DC converter 6 Inductor 7 Switch 8 Diode 9 Capacitor 10 Voltage / current detector 11 Control circuit 16 Switch 17 Switch 18 Start-up / drive power supply 19 Control circuit 20 DC / DC converter 21 Solar cell 22 Substrate 23 Solar cell 24 Start-up circuit 25 Switch 26 Switch 27 Switch 28 Inductor 29 Diode 30 Capacitor 31 Power storage circuit 32 Drive circuit 33 Inductor 34 Diode 35 Switch 36 Voltage / current detector 37 Control Circuit 38 Solar cell 39 Boost circuit 40 Secondary battery 41 Load 42 Solar cell 43 Power conversion device 44 Back surface reinforcing material

Claims (9)

In a photovoltaic power generation apparatus that performs power conversion with a configuration in which the output of a solar cell is input to a DC / DC converter,
At least one unit of DC / DC converter is connected to each cell of the solar battery,
Outputs of DC / DC converters of all the cells are connected in parallel to one system,
A photovoltaic power generation apparatus comprising: a first control circuit that controls each of the DC / DC converters so that the power output from each of the cells is equal.
The DC / DC converter has a plurality of chopper type booster circuits connected in parallel to the cell,
The solar power generation device according to claim 1, further comprising a second control circuit that controls an on / off time of a switch in each booster circuit.
A switching circuit for temporarily connecting some or all of the cells in series;
A power storage circuit that temporarily stores electric power obtained from a part or all of the solar cells connected in series by the switching circuit;
The photovoltaic power generation apparatus according to claim 1 or 2, wherein power stored in the power storage circuit is used as a power source of the DC / DC converter as needed.
The DC / DC converter connected to each cell is disposed behind the light receiving surface of each cell,
4. The solar power generation apparatus according to claim 1, further comprising means for wiring / connecting outputs of the respective DC / DC converters.
The DC / DC converter circuit connected to each cell is integrally formed on a part of the semiconductor forming the light receiving surface of each cell,
4. The solar power generation apparatus according to claim 1, further comprising means for wiring / connecting outputs of the respective DC / DC converters.
The DC / DC converter is
A startup circuit and a drive circuit as a power conversion circuit for performing a switching operation;
A power storage circuit for storing the output of the starter circuit or the drive circuit;
A power detection circuit for detecting a power level stored in the power storage circuit,
The storage circuit is for supplying power for the drive circuit operation,
The start circuit operates when the detection level of the power detection circuit is equal to or lower than a predetermined value, and the drive circuit operates when the detection level exceeds a predetermined value. 5. The solar power generation device according to 5.
A thermo switch and / or a reed switch that operates as a start switch in the start circuit by heat or electromagnetic force converted from output power of the solar cell,
The photovoltaic power generation apparatus according to claim 6, further comprising an FET as a steady driving switch in the driving circuit.
In a photovoltaic power generation apparatus that performs power conversion with a configuration in which the output of a solar cell is input to a DC / DC converter,
The DC / DC converter is
A startup circuit and a drive circuit as a power conversion circuit for performing a switching operation;
A power storage circuit for storing the output of the starter circuit or the drive circuit;
A power detection circuit for detecting a power level stored in the power storage circuit,
The storage circuit is for supplying power for the drive circuit operation,
A photovoltaic power generation apparatus, wherein a startup circuit operates when a detection level of the power detection circuit is a predetermined value or less, and a drive circuit operates when the detection level exceeds a predetermined value.
A thermo switch and / or a reed switch that operates as a start switch in the start circuit by heat or electromagnetic force converted from output power of the solar cell,
9. The photovoltaic power generation apparatus according to claim 8, further comprising an FET as a steady driving switch in the driving circuit.

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