JPH11186581A - Solar power generating equipment and electric power converter for solar power generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar power generation system of low cost which enables stable power supply by the use of an amorphous silicon thin film solar cell. SOLUTION: A reverse bias voltage output means for switching connection between solar cell arrays 11 -1n is installed in an electric power converter, and a reverse bias voltage is applied to a specified solar battery array for a specified time. The reverse bias voltage is supplied by the use of the solar battery arrays 1 which are connected in parallel via reverse current preventing diodes 3 and switches. The reverse bias voltage is applied to the selected solar battery array 1 through the operation of the switch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photovoltaic power generation system.

[0002]

2. Description of the Related Art As environmental problems such as global warming are taken up on a global scale, a photovoltaic power generation system is attracting attention as an energy system with a small environmental load. For example, FIG. 10 shows a residential photovoltaic power generation system that is currently spreading to ordinary households. In general, a residential photovoltaic power generation system synchronizes the DC power collected by the plurality of photovoltaic module arrays 1, the junction boxes 2 for connecting the respective photovoltaic module arrays 1 via the backflow prevention diodes 3, and the system voltage to the system voltage. Power conversion device (system-connected inverter device 4) that converts to converted AC power and performs interconnection operation with system 5
Consists of At present, there is a type in which the connection box 2 and the grid-connected inverter device are integrated.

[0003] Photovoltaic power generation can be broadly classified into a power generation system for the purpose of using the generated power for various purposes, and a consumer power generation system for a predetermined use such as a calculator and a clock. There is. Until now, silicon crystal-based solar cells have been mainly used as power generation systems for electric power. However, since silicon crystal-based solar cells cannot be integrated, voltage and current values cannot be freely designed, it is difficult to reduce the weight more than the current state, and supply of silicon wafers as raw materials There are problems such as a limited amount. Therefore, a photovoltaic power generation system using an amorphous silicon thin film solar cell that can be integrated, reduced in weight and flexible, and can be manufactured with a small amount of source gas is currently being developed.

[0004]

The thin-film solar cell has features that it can be integrated, reduced in weight and flexible, can be manufactured by using a small amount of source gas, and can be reduced in cost. Therefore, although it is currently drawing attention, there is a problem that its stability to light is poor. That is, if the light is continuously applied for a long time, the photoelectric conversion efficiency gradually decreases, and finally, the photoelectric conversion efficiency is 10 to 20 compared with the initial photoelectric conversion efficiency immediately after the production of the amorphous silicon thin film solar cell.
The phenomenon of stabilization occurs when the percentage decreases. This phenomenon is called photo-deterioration of amorphous silicon thin-film solar cells, and research is being conducted to elucidate photo-deterioration phenomena from various angles. No method has been found to eliminate light degradation.

[0005] For this reason, when a solar power generation system using an amorphous silicon thin film solar cell is manufactured, an unstable solar power generation system in which the total amount of power generation differs between when the system is installed and when the system is used for several months. There was a problem that becomes. Further, when a photovoltaic power generation system is designed on the basis of the photoelectric conversion efficiency after photodegradation, a solar cell having a larger area is required, and as a result, the cost also increases. This is a problem that is not limited to the amorphous silicon thin film solar cell in which the photodegradation phenomenon appears remarkably, but is also common to a crystalline thin film solar cell containing some microcrystals and other thin film solar cells. .

It is known that such photo-deterioration is recovered to some extent by heat treatment of the amorphous silicon thin-film solar cell, and Japanese Patent Application Laid-Open No. 7-202230 proposes a thermal annealing method using a heat insulating material. However, the degree of recovery is not sufficient, and the temperature of the solar cell rises during operation and conversion efficiency is low, and the cost increases due to the use of a heat insulating material.

Further, Japanese Patent Application Laid-Open No. 63-30778, filed by the Company.
No. 2 proposes a method for manufacturing a high-efficiency morphous silicon thin-film solar cell in which near-infrared light is irradiated while applying a reverse bias to the solar cell. It is not described, nor is it shown to irradiate sunlight.

The present invention has been made in view of the above problems, and provides a low-cost photovoltaic power generation system capable of supplying stable power using an amorphous silicon thin film solar cell. The purpose is to:

[0009]

In the photovoltaic power generator of the present invention, a reverse bias voltage is applied to a solar cell receiving sunlight for a predetermined period. Thereby, the solar cell can recover from light degradation.

Further, the power converter for photovoltaic power generation of the present invention has a reverse bias applying means for generating a reverse bias voltage and applying the reverse bias voltage to the solar cell for a predetermined period of insolation. Accordingly, the solar cell receives sunlight in a reverse bias state, so that the solar cell can recover from light degradation.

According to the first aspect, by applying a reverse bias voltage to the solar cell for a predetermined period, the deterioration of the characteristics of the solar cell is recovered.

According to the second aspect, since the reverse bias voltage is applied to the solar cell only for the photo-deteriorated solar cell for a predetermined period, the characteristic deterioration of the solar cell can be efficiently recovered.

According to the third aspect, the power conversion device for photovoltaic power generation which receives the DC power generated by the solar cell as an input can be provided with a light deterioration recovery function.

According to a fourth aspect of the present invention, in a power converter for photovoltaic power generation which receives DC power generated by a solar cell as input, a reverse bias generating means is provided, and a reverse bias voltage is applied to the solar cell for a predetermined period. Is applied, the characteristic deterioration of the solar cell is recovered.

According to a fifth aspect of the present invention, in the configuration of the reverse bias generating means, the connection wiring of the plurality of solar cell module arrays input to the power converter for photovoltaic power generation is switched by a relay or a semiconductor switch element. It is configured to apply a reverse bias voltage to a predetermined solar cell module array. At this time, the reverse bias voltage is created by connecting the remaining solar cell module arrays.

For example, FIG. 9A shows an I (current) -V (voltage) characteristic of a solar cell array for generating a reverse bias voltage, and FIG. 9 shows an IV characteristic of a solar cell array to which a reverse bias is applied. When these are connected as a curve 2 in (b), the position of the short-circuit current value _Im2 of the solar cell array in FIG.
The voltage at that time is V _{B in} FIG. Then, this voltage is applied as a reverse bias to the solar cell array of FIG. 9B, thereby recovering from light degradation. At this time, as is apparent from FIG. 9, the short-circuit current _Im3 of the solar cell array for generating reverse bias must be connected so as to be larger than the short-circuit current _Im2 of the solar cell array to which reverse bias is to be applied.

According to a sixth aspect of the present invention, in the configuration of the reverse bias generation means, a DC / DC converter generates a reverse bias voltage from the DC power of a plurality of solar cells input to the power converter for photovoltaic power generation. The reverse bias is applied to the predetermined solar cell by the switch means. Therefore, even when the voltage obtained from the solar cell array is low, the voltage is boosted to obtain a necessary reverse bias voltage value, thereby recovering light degradation. Can be increased. Since the reverse bias voltage value is stabilized by the control, if there is a margin in the supply power at the time of reverse bias, the inverter body can also perform the system interconnection operation with the excess power.

According to a seventh aspect of the present invention, in a system interconnection inverter having a solar cell as an input, a DC power supply circuit having a system voltage as an input is configured to generate a reverse bias voltage. The reverse bias voltage can be supplied even when power cannot be obtained from the solar cell due to the effects of solar radiation.

According to the present invention, the input of the DC / DC converter is supplied from the secondary side DC stage of the high-frequency insulation system interconnection inverter, so that the electric power required for the DC power supply circuit in the fourth embodiment is reduced by the system. Rectified through the flywheel diode of the commercial frequency inverter bridge in the inverter main circuit, so that the rectifying circuit of the DC power supply circuit can be reduced.

According to the ninth aspect, the DC power supply circuit for generating a reverse bias voltage or the DC / DC converter circuit has series switching means at the output end, and the DC voltage output from these circuits is determined after the DC voltage output is determined. Is closed to apply a reverse bias to the solar cell, and open the series switch to cancel the reverse bias before the DC voltage output is stopped, so that the reverse voltage by the solar cell is applied to the output capacitor of the DC power supply circuit. It has the effect of preventing that. When the circuit is closed to apply a reverse bias to the solar cell when power is not supplied to the DC power supply, the electrolysis capacitor of the power supply circuit is charged at a reverse potential by the electromotive force of the solar cell itself. This can be prevented.

According to the tenth aspect, by connecting a reverse-biased parallel diode between output lines of the DC power supply circuit that generates a reverse bias, the DC power supply circuit can be connected to the DC power supply circuit in a state where power is not supplied. Even when the output is connected to the solar cell array, since the solar cell array is in a short-circuit state via the parallel diode, reverse charging is not performed on the output capacitor of the power supply circuit.

According to the eleventh aspect, in the power converter for photovoltaic power generation which receives the DC power generated by the solar cell as an input, a predetermined period during which the solar cell receives sunlight is selected. A reverse bias voltage can be applied.

According to the twelfth aspect, there is provided means for estimating the solar radiation intensity of the solar cell, and the current value flowing through the solar cell at the time of applying the reverse bias is small, and the period of the low solar radiation intensity within a range where deterioration can be recovered is set. By selecting and applying a reverse bias, the power required for applying the reverse bias can be reduced. Even when the amount of solar radiation applied to the solar cell at the time of applying the reverse bias is small, the same recovery effect as when the amount of solar radiation is large can be obtained. When the solar radiation to the solar cell decreases, the IV characteristic of the solar cell shifts from the curve 1 to the curve 2 in FIG. Thus since the short-circuit current I _m better when less solar radiation decreases, it is possible to reduce the amount of power required during reverse bias.

According to the thirteenth aspect, a reverse bias is applied by selecting a time zone with low solar radiation by applying a reverse bias to the solar cell at a predetermined time in the morning and evening by providing a calendar device. Therefore, the amount of power required at the time of reverse bias can be reduced as described above.

According to a fourteenth aspect of the present invention, there is provided a configuration in which a means for estimating the efficiency of the solar cell is provided, and a reverse bias is applied to the solar cell when a decrease in efficiency exceeding a predetermined reference is detected. The reverse bias operation can be performed only when the efficiency is deteriorated, which leads to an improvement in system efficiency.

According to claim 15, in the power converter for photovoltaic power generation according to any one of claims 4 to 14, the photovoltaic cell that generates power is an amorphous photovoltaic cell. large.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining an output recovery method in a photovoltaic power generator according to the present invention. A solar cell array 1 comprising one or more solar cells 24 is opened and closed by a reverse bias applying means 25. 27 is closed and a reverse bias is applied. At this time, the solar cell array 1 is receiving sunlight. The reverse bias applying means 25 may be incorporated in the photovoltaic power converter 26.
The solar cell 24 may be a crystalline thin-film solar cell, an amorphous silicon solar cell,
Other solar cells may be used.

FIG. 2 is a block diagram of a photovoltaic power generation system according to a first embodiment of the present invention, and shows a grid-connected inverter device 9 as an example of a photovoltaic power conversion device 26. DC power of one or a plurality of solar cell arrays 1 is input to the grid-connected inverter 9, and the grid-connected inverter 9 converts AC power synchronized with the grid voltage into the commercial grid 5.
Output to DC power of the solar cell array 1 ₁ to 1 _n is via a blocking diode 3 in the system interconnection inverter 9, is input to the relay 8 ₁ to 8 _n, the output of the relay 8 2
And are input to the inverter main circuit 6. Current waveform control, maximum power follow-up control, and interconnection protection control in the inverter main circuit 6 are performed by the control circuit 7, and output AC power to the commercial system 5. The control circuit 7 further controls the contact switching of the relay 8 by the relay signal R.

In FIG. 2, when all the relays 8 are connected to the "a" contact side, the connection is the same as that of the conventional system interconnection inverter, and normal interconnection operation can be performed. Here, when only the relay 8 _n is connected to the contact b, the connection of the solar cell array 1 is connected as shown in FIG. 3, and when there is solar radiation, a reverse bias voltage is applied to the solar cell array 1 _n . The reverse bias voltage at this time is the solar cell array 1 ₁
Occurs in a parallel array of ~ 1n _-1 . To apply a reverse bias in this way, the contact of the relay 8 to which the solar cell array is connected may be connected to the contact b. Further, if the parallel array has a margin of power, the inverter main circuit can continue the interconnection operation within a range until the output of the parallel array decreases to the minimum voltage value required for reverse bias. As described above, in the present embodiment, the reverse bias generating means is constituted by the n relays 8 and their interconnections.

Further, in the connection shown in FIG. 3, when the reverse bias voltage required for recovery from light deterioration is insufficient, the relay 8 is connected so that the solar cell arrays can be connected in series and parallel as shown in FIG.
Can also be configured. Further, the configuration of FIG. 2 has a calendar circuit 10 and outputs a reverse bias application command T to a control circuit at a predetermined date and time. Upon receiving the reverse bias application command T, the control circuit sequentially switches the contacts of the relay 8 for a predetermined period to apply a reverse bias to each solar cell array, and lowers the inverter output to a level at which a predetermined reverse bias voltage is obtained. The calendar circuit 10 has a memory function, and can set the time zone for outputting the reverse bias application command in the morning and evening hours with less solar radiation according to the season. Although a relay is used as the connection switching means in FIG. 2, a semiconductor switch can be similarly configured.

FIG. 5 is a block diagram of a photovoltaic power generation system according to a second embodiment of the present invention, and shows a grid-connected inverter device 9 as an example of a photovoltaic power conversion device 26. The difference from the first embodiment is that, in the first embodiment, the reverse bias generating means is constituted only by the relay 8, whereas in FIG. This is a point that the DC / DC converter 11 receives the DC power of the solar cell input through the DC / DC converter.

In FIG. 5, when all the relays 8 are connected to the contact a, the connection is the same as that of a normal system interconnection inverter. Here, when the reverse bias application command T is output from the calendar circuit, the control circuit activates the DC / DC converter 11. DC / DC converter outputs a reverse bias voltage to the input DC power to V _in via the relay 8 from the solar cell array from V _out. The control circuit 7 is D
After confirming that the output voltage of the C / DC converter is the set value, the contact of the relay 8 is sequentially switched to apply a reverse bias to each solar cell array 1. In FIG. 5, only the relay 8 _n is connected to the contact b, and the solar cell array 1
_A reverse bias is applied to _n . Further, the control circuit 7 can output all the power other than the power used for applying the reverse bias to the system side via the inverter main circuit by continuing the maximum power point tracking control of the solar cell.

FIG. 6 is a configuration diagram of a photovoltaic power generation system showing a third embodiment according to the present invention, and shows a grid-connected inverter device 9 as an example of a photovoltaic power conversion device 26. The difference from the second embodiment is that the output of the DC / DC converter for generating reverse bias is also input to the inverter main circuit 6. In FIG. 6, DC
The / DC converter 11 is obtained by adding a parallel diode 13 to a boost chopper circuit. This parallel diode 13
Prevents the electrolytic capacitor 14 from being charged with a reverse voltage by the solar cell array. Since this step-up chopper circuit is part of the main circuit of the transformerless system interconnection inverter, it can be shared with the reverse bias generation DC / DC converter, and the number of components can be greatly reduced. In FIG. 6, the basic operation of switching the relay 8 is the same as that in FIG.

FIG. 7 is a block diagram of a photovoltaic power generation system showing a fourth embodiment according to the present invention, and shows a grid-connected inverter device 9 as an example of a photovoltaic power conversion device 26. The difference from the third embodiment is that the input of the DC power supply circuit 15 for generating reverse bias is supplied from the commercial system 5. Therefore, since the power supply for generating the reverse bias is stabilized, the configuration is such that the reverse bias can be applied to all the solar cell arrays 1 via the relay 8 at the same time. Of course, it is also possible to apply a reverse bias while sequentially switching using a plurality of relays as in the first to third embodiments. In FIG. 7, a parallel diode 13 is attached to the output terminal of the DC power supply circuit. When the relay 8 is connected to the contact b, the electrolytic capacitor (not shown) of the output of the DC power supply circuit 15 is reversely charged. Is preventing.

[0035] The inverter output current I ₀ detected by the current detector 16 from the inverter main circuit in FIG. 7, the output voltage V ₀ to be detected through the voltage transformer 17, by a signal such as an inverter input voltage V _I The control circuit 7 controls the maximum power tracking of the solar cell. Therefore, the current solar radiation to the solar cell can be estimated from the inverter output power obtained from the output current I ₀ and the output voltage V ₀ .
When the solar radiation intensity estimated here is small, the control circuit 7 connects the relay 8 to the contact b and activates the DC power supply circuit 15 to apply a reverse bias to the solar cell array 1. As described above, in FIG. 7, the insolation intensity estimating means includes the current detector 16, the voltage transformer 17, the control circuit 7, and the like.

If the solar radiation meter 22 is installed in the solar cell array 1 and the data is taken into the control circuit 7 as data, the efficiency of the solar cell array can be estimated from the current inverter output power and the solar radiation data. When the estimated efficiency falls below a predetermined reference, the control circuit 7 can connect the relay 8 to the contact b, activate the DC power supply circuit 15 and apply a reverse bias to the solar cell array 1.

FIG. 8 is a block diagram of a photovoltaic power generation system showing a fifth embodiment according to the present invention, and shows a grid-connected inverter device 9 as an example of a photovoltaic power conversion device 26. The difference from the fourth embodiment is that the input of the DC / DC converter 11 for generating reverse bias is connected to the DC filter unit 2 of the high-frequency insulation system interconnection inverter 18.
3 is provided.

The high-frequency insulation type system interconnection inverter 18 is roughly composed of a high-frequency inverter 19 for converting DC into high-frequency AC, a diode bridge 21 for rectifying the high-frequency AC isolated by a high-frequency transformer, and a DC filter 2.
3 and a low-frequency inverter 20 for converting into AC of commercial frequency. DC /
If the input of the DC converter 11 is supplied from the DC filter unit 23 of the high-frequency insulation system interconnection inverter 18, the power from the commercial system 5 is rectified through the parasitic diode of the low-frequency inverter 20 and charges the capacitor of the DC filter 23. Therefore, the rectifying circuit portion of the DC power supply circuit 15 in FIG. 7 can be omitted. The other configuration has already been described in the above embodiment, and a description thereof will be omitted.

[0039]

As described above, according to the first aspect, the characteristic deterioration of the solar cell is restored by applying the reverse bias voltage to the solar cell for a predetermined period. Efficiency is improved.

According to the second aspect, since the reverse bias voltage is applied to the solar cell only for the photo-deteriorated solar cell for a predetermined period, the characteristic deterioration of the solar cell can be efficiently recovered. The system efficiency of the power generation system is further improved.

According to the third aspect, the power conversion device for photovoltaic power generation, which receives DC power generated by the solar cell as an input, can be provided with a light deterioration recovery function, and can be maintained and managed as a photovoltaic power generation system. .

According to a fourth aspect of the present invention, in a power converter for photovoltaic power generation using DC power generated by a solar cell as an input, a reverse bias generating means is provided, and a reverse bias voltage is applied to the solar cell for a predetermined period. Is applied, the deterioration of the characteristics of the solar cell is recovered, so that the system efficiency of the solar power generation system is improved. Further, the maintenance work is reduced by providing the power converter with a reverse bias application function.

According to the fifth aspect, since the configuration of the reverse bias generating means is only connection switching of the solar cell module array, it can be realized at low cost.

According to the sixth aspect of the present invention, in the configuration of the reverse bias generating means, a DC / DC converter generates a reverse bias voltage from the DC power of a plurality of systems of solar cells input to the photovoltaic power converter. The reverse bias is applied to the predetermined solar cell by the switch means. Therefore, even when the voltage obtained from the solar cell array is low, the voltage is boosted to obtain a necessary reverse bias voltage value, thereby recovering light degradation. Can be increased. Furthermore, if there is a margin in the supply power at the time of reverse bias, the inverter body can also be connected to the system with the excess power, so that the system efficiency is improved. If the DC / DC converter is also used as a step-up chopper circuit of a transformerless system interconnection inverter, the cost can be reduced.

According to the seventh aspect, in a system interconnection inverter having a solar cell as an input, a DC power supply circuit having a system voltage as an input is configured to generate a reverse bias voltage, thereby enabling a reverse bias voltage to be applied. The reverse bias voltage can be supplied even when power cannot be obtained from the solar cell due to the effects of solar radiation.

According to the eighth aspect, the input of the DC / DC converter is supplied from the secondary side DC stage of the high-frequency insulation system interconnection inverter, whereby the rectifier circuit of the DC power supply circuit according to the seventh aspect is reduced. Cost can be reduced.

According to the ninth aspect, the DC power supply circuit for generating a reverse bias voltage or the series switching means at the output end of the DC / DC converter circuit has the series switching means. Is closed, a reverse bias is applied to the solar cell, and the series switch is opened to stop the reverse bias before the DC voltage output is stopped, so that the reverse voltage by the solar cell is an electrolytic capacitor of the output of the DC power supply circuit. To prevent the electrolytic capacitor from being destroyed.

According to the tenth aspect, by connecting a reverse-biased parallel diode between the output lines of the DC power supply circuit that generates a reverse bias, the DC power supply circuit can be connected in a state where power is not supplied to the DC power supply circuit. Even when the output is connected to the solar cell array, the solar cell array is short-circuited via the parallel diode, so that the output capacitor of the power supply circuit is not reverse-charged, and the output electrolytic capacitor of the DC power supply circuit is not charged. It has the effect of preventing destruction.

According to the eleventh aspect, in the power converter for photovoltaic power generation which receives the DC power generated by the solar cell as an input, a predetermined period during which sunlight is received by the solar cell is selected. Since the reverse bias voltage can be applied, the efficiency of the system is improved.

According to the twelfth aspect, there is provided means for estimating the solar radiation intensity of the solar cell, and the current value flowing through the solar cell at the time of applying the reverse bias is small, and the period of the low solar radiation intensity within a range in which deterioration can be recovered is set. By selecting and applying a reverse bias, the power required for applying the reverse bias can be kept low, so that the efficiency of the system is further improved.

According to the thirteenth aspect, by providing a reverse bias to the solar cell at a predetermined time in the morning and evening by providing a calendar device, a reverse bias is applied by selecting a time zone with low solar radiation. Therefore, the amount of electric power required at the time of reverse bias can be reduced, so that there is an effect of improving system efficiency.

According to a fourteenth aspect of the present invention, there is provided a configuration in which a means for estimating the efficiency of the solar cell is provided, and a reverse bias is applied to the solar cell when a decrease in efficiency over a predetermined reference is detected. The reverse bias operation can be performed only when the efficiency is deteriorated, which leads to an improvement in system efficiency.

According to the fifteenth aspect, since the solar cell that generates electric power is an amorphous thin-film solar cell, the degree of recovery is large and the effect is large because of large light degradation.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an output recovery method according to the present invention.

FIG. 2 is a configuration diagram of a photovoltaic power generation system according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of connection of the solar cell array of the present invention.

FIG. 4 is an explanatory diagram of connection of the solar cell array of the present invention.

FIG. 5 is a configuration diagram of a photovoltaic power generation system according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a photovoltaic power generation system according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram of a photovoltaic power generation system according to a fourth embodiment of the present invention.

FIG. 8 is a configuration diagram of a photovoltaic power generation system according to a fifth embodiment of the present invention.

FIG. 9 is a current-voltage characteristic diagram of the solar cell array of the present invention.

FIG. 10 is a configuration diagram of a conventional solar power generation system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solar cell array 2 Connection box 3 Backflow prevention diode 4 Inverter device 5 Commercial system 6 Inverter main circuit 7 Control circuit 8 Relay 9 Grid interconnection inverter 10 Calendar circuit 11 DC / DC converter 13 Parallel diode 14 Electrolytic capacitor 15 DC power supply circuit 16 Current detector 17 Voltage transformer 18 High frequency insulation type inverter main circuit 19 High frequency inverter 20 Low frequency inverter 21 Diode bridge 22 Solar radiation meter 23 DC filter 24 Solar cell 25 Reverse bias applying means 26 Photovoltaic power converter 27 Open / close switch

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Michi Sakai, Inventor 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside (Sharp) (72) Inventor Masaru Kuzen 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka (72) Inventor Katsuhiko Nomoto 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka

Claims (15)

[Claims] 1. A solar cell receiving sunlight,
A photovoltaic power generator, comprising: a reverse bias voltage applying means for applying a reverse bias voltage for a predetermined period to recover deterioration of characteristics of a solar cell. 2. The photovoltaic power generator according to claim 1, wherein the photovoltaic cell is photo-degraded. 3. The solar battery according to claim 1, wherein a reverse bias voltage is applied to the solar cell for a predetermined period by a photovoltaic power conversion device incorporating a reverse bias voltage applying unit. Solar power generator. 4. A photovoltaic power conversion device that receives DC power generated by a solar cell as an input and applies a reverse bias voltage to the solar cell for a predetermined period to recover deterioration in characteristics of the solar cell. A power converter for photovoltaic power generation, comprising reverse bias applying means. 5. The power converter for photovoltaic power generation according to claim 4, further comprising a plurality of solar cell input terminals, wherein the short-circuit current of the solar cell to which a reverse bias is to be applied is another solar cell for generating a reverse bias. The wiring between the solar cells connected to the solar cell input terminal is switched so as to be smaller than the short circuit current of the battery, and a predetermined solar cell input terminal is reverse-biased by a solar cell connected to another solar cell input terminal. And a reverse bias applying means for generating and applying a voltage. 6. The power converter for photovoltaic power generation according to claim 4, comprising a plurality of solar cell input terminals, wherein a wiring between the solar cells connected to the solar cell input terminals is switched to provide a predetermined solar cell. A switch means for applying a reverse bias to an input terminal, and a DC / DC converter for increasing a DC voltage of a solar cell connected to another solar cell input terminal to generate a reverse bias voltage. Power conversion device for photovoltaic power generation. 7. The inverter according to claim 4, wherein the DC power output from the solar cell is input, converted into AC power synchronized with a system voltage, and connected to the system for operation. A DC power supply circuit for inputting a system voltage to generate the reverse bias voltage, and switch means for connecting an output voltage of the DC power supply to the solar cell to apply a reverse bias to the solar cell for a predetermined period. A power converter for photovoltaic power generation. 8. The power converter for photovoltaic power generation according to claim 4, wherein the DC power output from the solar cell is input, converted to AC power synchronized with a system voltage, and connected to the system for high-frequency operation. An insulation type inverter, a DC / DC converter for inputting a voltage of a secondary DC stage of the high frequency insulation type inverter to generate the reverse bias voltage, and a DC / DC converter for applying a reverse bias to a solar cell for a predetermined period. Switch means for connecting the output voltage of the DC / DC converter to the solar cell. 9. The power converter for photovoltaic power generation according to claim 6, wherein the DC power supply circuit for generating a reverse bias has series switching means at an output terminal thereof, and the DC power supply circuit is activated. Then, after the output voltage is determined, the series switch is closed, and before the DC power supply circuit is stopped, the series switch is opened to prevent the reverse voltage by the solar cell from being applied to the output capacitor of the DC power supply circuit. Characteristic power converter for photovoltaic power generation. 10. The power converter for photovoltaic power generation according to claim 6, further comprising a parallel diode connected in reverse bias between output lines of a DC power supply circuit for generating reverse bias. Power converter for photovoltaic power generation. 11. The power converter for photovoltaic power generation according to claim 4, further comprising: means for estimating whether or not the solar cell is receiving sunlight, wherein a predetermined value is provided when the sunlight is received. Applying a reverse bias during the period of. 12. The photovoltaic power converter according to claim 4, further comprising: means for estimating the intensity of solar radiation received by the solar cell, wherein the power flows to the solar cell when a reverse bias is applied. A power converter for photovoltaic power generation, wherein a reverse bias is applied by selecting a period in which a current value is small and a low solar radiation intensity within a range in which deterioration can be recovered. 13. The solar power generation apparatus according to claim 4, further comprising a calendar device, wherein a reverse bias is applied to the solar cell at a predetermined morning and evening time. Power converter for photovoltaic power generation. 14. The photovoltaic power converter according to any one of claims 4 to 12, further comprising: means for estimating the conversion efficiency of the solar cell, wherein when a reduction in efficiency above a predetermined reference is detected, A power converter for photovoltaic power generation, wherein a reverse bias is applied to a solar cell. 15. The power converter for photovoltaic power generation according to claim 4, wherein said solar cell is an amorphous silicon thin film solar cell.