JP2014099438A - Output drop prevention and recovery device and output drop prevention and recovery method of solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an output drop prevention and recovery device of a solar cell module which is installed between the solar cell module and a power conditioner, and operated to prevent PID phenomenon, and to recover the output drop upon occurrence.SOLUTION: An output drop prevention and recovery device of a solar cell module installed outdoors includes circuit switching means for switching between a normal power generation circuit and the output drop prevention and recovery device in units of a single solar cell module or an array consisting of a plurality of solar cell modules, power supply means for applying a positive voltage in the solar cell module, and ground means for grounding the solar cell module.

Description

    The present invention relates to a method and apparatus for installing a solar cell outdoors or the like to recover and prevent a decrease in output due to a PID phenomenon.

  The PID phenomenon that has become apparent in recent years is a phenomenon in which when a solar cell module is exposed to a negative voltage with respect to the ground, the solar cell loses its semiconductor function and the power generation amount decreases.

  It is known that the PID phenomenon is eliminated by applying a positive voltage and the output is recovered. The following facts are disclosed in the academic literature. 1) If a high temperature, high humidity, and electric field can be applied uniformly and positively when a positive voltage is applied, output recovery is accelerated. 2) Output recovery is accelerated by placing high temperature, high humidity, aluminum foil, metal plate, etc. on the glass.

  When a PID phenomenon occurs in a solar cell module installed outdoors and the output drops, it takes a lot of labor and cost to remove it from the installation location, take it back to the laboratory, etc., and perform the output recovery work as described above. Take it.

  The PID phenomenon does not occur unless a negative voltage is applied to the cell. However, a transformerless power conditioner that is currently becoming the mainstream and has a low cost, a light weight, and a high conversion efficiency cannot be configured such that a negative voltage such as a negative electrode ground is not applied.

  On the other hand, Patent Document 1 proposes a method for preventing the generation of PID by adding an insulating transformer to the power conversion device used in the solar cell module power generation system and grounding the negative electrode, but the cost increases. In addition, there is a disadvantage that the conversion efficiency is lowered.

  Further, as a method for preventing the PID phenomenon, there is a method of manufacturing a solar cell module using solar cells having a configuration in which the PID phenomenon hardly occurs. However, in this method, although the progress of the PID phenomenon is certainly slow, it has been confirmed that PID occurs after a longer time than usual.

  So far, there is no disclosure of a specific method or apparatus for recovering the output of the solar cell module whose output has been reduced due to the PID phenomenon or preventing the PID phenomenon with the solar cell module installed outdoors.

JP 2011-103497 A

  The present invention has been made in view of the above circumstances. By installing and operating between a solar cell module and a power conditioner, the PID phenomenon can be prevented and the output can be restored when it occurs. It is an object of the present invention to provide an output reduction preventive recovery apparatus and an output decrease preventive recovery method of a solar cell module.

  In order to achieve the above object, an output reduction preventive recovery device according to the first aspect of the present invention is an output decrease preventive recovery device for a solar cell module installed outdoors, wherein the solar cell module alone or an array unit comprising a plurality of solar cell modules. Circuit switching means for switching between the power generation circuit and the output reduction prevention recovery device, a power supply means for applying a positive voltage inside the solar cell module, and a grounding means for grounding the solar cell module It is characterized by.

  According to 1st invention, generation | occurrence | production of the PID phenomenon of the solar cell module installed outdoors can be prevented, and the output fall can be prevented. Moreover, even if it turns out that the output of the solar cell module is reduced due to the PID phenomenon, the output reduction can be recovered at the place where the solar cell module is installed. Furthermore, since the power generation circuit and the circuit of the output recovery prevention device are switched in a form in which a single solar cell module and a plurality of solar cell modules are connected (hereinafter abbreviated as “array” or “array unit”), output is caused by the PID phenomenon. The power generation operation can be continued except for the solar cell modules and arrays that have been degraded or that are likely to experience the PID phenomenon.

  According to a second aspect of the present invention, there is provided an apparatus for preventing and recovering output reduction, further comprising a humidity detecting means for detecting the humidity of the installation atmosphere of the solar cell module, and the temperature of the installation atmosphere of the solar cell module. And a temperature detecting means for detecting.

  According to the second invention, since the atmosphere of the solar cell module installed outdoors is provided with means for detecting the temperature and humidity at which the PID phenomenon occurs, it is possible to constantly measure and monitor. Therefore, when the situation where the occurrence of the PID phenomenon is expected, the output reduction prevention recovery apparatus can be automatically operated. Therefore, the occurrence of the PID phenomenon of the solar cell module can be reliably prevented.

  According to a third aspect of the present invention, there is provided an output decrease prevention / recovery device in which the output decrease prevention / recovery device according to the first or second invention is installed in a power conversion system of a solar cell module.

  According to the third aspect of the present invention, the output reduction prevention / recovery device for the solar cell module is incorporated in the power conversion system, so that the prevention can be prevented even if the PID phenomenon is likely to occur in the installed solar cell module. it can. Moreover, even if the output is reduced due to the PID phenomenon, the output reduction can be recovered at the installation location.

  According to a fourth aspect of the present invention, there is provided an output reduction preventive recovery device according to the first invention, wherein the output decrease prevention recovery device described in the first invention is in an atmosphere state where the output decrease of the installed solar cell module is found or the installation location causes the output decrease. When it is found out, it is characterized in that it is installed at the place where the solar cell module is installed and the output reduction of the solar cell module is prevented and recovered.

  According to the fourth aspect of the invention, the output reduction prevention / recovery device for the solar cell module can be separated from the power conversion system, so that the solar cell power generation system can have a conventional simplified form, and the solar cell module. It is possible to prevent and recover the output.

  In order to achieve the above object, a method for preventing and recovering output reduction according to a fifth aspect of the present invention is a method for preventing and recovering output reduction of a solar cell module installed outdoors, wherein the solar cell module alone or an array unit comprising a plurality of solar cell modules A step of switching the circuit between the power generation circuit and the output reduction prevention recovery device, a step of applying a positive voltage inside the solar cell module, and a step of grounding the solar cell module. Yes.

  According to the fifth aspect, the same effect as in the first aspect can be exhibited.

  According to a sixth aspect of the present invention, there is provided a method for preventing and recovering a decrease in output. The method for preventing and recovering a decrease in output according to the fifth aspect further includes a step of detecting the humidity of the installation atmosphere of the solar cell module and the temperature of the installation atmosphere of the solar cell module. And a step of performing the process.

  According to the sixth aspect, the same effect as in the second aspect can be exhibited.

  According to a seventh aspect of the present invention, there is provided the output reduction prevention and recovery device according to the first aspect, wherein the grounding means for grounding the solar cell module uses a frame of the solar cell module.

  According to the seventh invention, since the frame of the solar cell module is used as the grounding means for grounding the solar cell module, it is possible to easily ground and prevent the solar cell module from lowering the output.

  According to an eighth aspect of the present invention, there is provided an output reduction preventing recovery apparatus according to the first invention, wherein the grounding means for grounding the solar cell module uses a metal plate installed on a transparent substrate of the solar cell module.

  According to the eighth invention, since the grounding means for grounding the solar cell module uses a metal plate installed on the transparent substrate of the solar cell module, the output decrease of the solar cell module whose output is reduced due to the PID phenomenon. Recovery can be performed in a short time.

  The output reduction prevention recovery method of the ninth invention, in either the fifth invention or the sixth invention, when it is found that the output reduction of the installed solar cell module is found or is in a state of causing the output reduction, The output reduction prevention and recovery device of the first invention is installed at the installation location of the solar cell module, and the output reduction prevention recovery of the solar cell module is performed.

  According to the ninth aspect, the same effect as in the fourth aspect can be exhibited.

Explanatory drawing of a solar cell module single-piece | unit. Explanatory drawing of a solar cell module array. 1 is a block diagram of an output reduction prevention and recovery device according to Embodiment 1. FIG. Explanatory drawing of the switching state of SW of the output fall prevention recovery apparatus of this invention. The block diagram of the output fall prevention recovery apparatus of Example 2. FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  Example 1 will be described with reference to the drawings. FIG. 1 is an explanatory diagram of a single solar cell module. FIG. 2 is an explanatory diagram of a solar cell module array. FIG. 3 is a block diagram of the output drop prevention and recovery device according to the first embodiment. FIG. 4 is an explanatory diagram of the switching state of the SW of the output decrease prevention / recovery device of the present invention.

<1> Solar Cell Module Single Unit Here, a single solar cell module targeted by the apparatus of the present invention will be described. FIG. 1A is a plan view showing a configuration of a solar cell module using a crystal cell as the solar cell module 10. FIG. 1B is a cross-sectional view of FIG. As shown in the figure, the solar cell module 10 has a configuration in which a plurality of strings 14 are sandwiched between a transparent cover glass 11 and a back material 12 via fillers 13 and 13. A material such as polyethylene resin is used for the back material 12. Further, EVA (ethylene vinyl acetate) resin or the like is used for the fillers 13 and 13. The string 14 has a configuration in which solar cells 16 as crystal cells are connected between electrodes 15 and 15 via lead wires 17. The constituent members of the solar cell module laminated in this way are laminated by a laminating apparatus. Then, the sealing material 19 etc. are apply | coated to the peripheral part of a solar cell, the frame material 18 is set, and the solar cell module 10 is formed.

<2> Solar cell module array In the solar cell power generation system, a plurality of such solar cell modules are connected in series to form a solar cell module array A. FIG. 2 illustrates such a state. FIG. 2 is a schematic explanatory diagram of the array, in which four arrays are arranged. Each array is schematically shown as being composed of six solar cell modules.

  The positive electrode and the negative electrode of each array are connected to a power conditioner (hereinafter abbreviated as “PCS”) via a connection box. The PID output reduction preventive recovery device of the present invention is provided between the junction box and the PCS. This embodiment will be described later with reference to FIG. 3 (see FIG. 5 for Embodiment 2). 2 and 3 (see FIG. 5 for the second embodiment), the output reduction prevention recovery device 20 after the terminal box and the PCS are collectively referred to as a power conversion system.

  The generated voltage of the single solar cell module is about 40-50V. A typical array has about 12 solar cell modules connected in series. Therefore, the generated voltage of the solar cell module array is about 600V. With such a high voltage, the PID phenomenon occurs due to the environmental conditions of the installation location, and the output of the solar cell module is reduced.

<3> Output Reduction Prevention / Recovery Device The configuration of the output prevention / recovery device (hereinafter referred to as “the device of the present invention” or “the present device”) of this embodiment will be described with reference to the block diagram of FIG. The apparatus of the present invention is inserted between the array A and the PCS in which the solar cell modules are connected. The PCS is a power conversion device that converts a direct current generated from a solar cell module into an alternating current. Further, a single solar cell module or a solar cell module array is hereinafter abbreviated as a solar cell.

  The apparatus 20 includes a circuit switching unit 21, a power source unit 22, a ground unit 23, and a control unit 24, and performs a recovery operation of the output of the solar cell whose output has decreased due to the PID phenomenon. Alternatively, when the occurrence of a PID phenomenon is predicted, the present apparatus operates the apparatus to perform the prevention work. Hereinafter, each means will be described.

1) The circuit switching means 21 has a function of separating the PCS and the solar cell, and further making the solar cell frame and the ground of the positive voltage application circuit the same. It has a plurality of switching SWs and is operated by the control means. In FIG. 3, five SWs are provided. Detailed operation will be described later.
2) The power source means 22 disconnects the PCS and the solar cell by the circuit switching means described above, and applies a positive voltage between the positive electrode and the negative electrode of the solar cell. The positive voltage applied here is DC400V, for example.
3) The grounding means 23 is a ground for performing an output reduction preventive recovery work for a solar cell whose output has decreased, and normally uses a frame of a solar cell module. However, when the output reduction is severe and the output reduction recovery work is performed in a short time, a metal plate such as an aluminum plate is installed on the transparent substrate (eg, glass plate) of the solar cell module and used as a grounding means. You can also
4) The control means 24 controls the operation of the circuit switching means 21 including the switch SW, the operation of the power supply means 22 and the selection of the operation mode of the apparatus, and a personal computer (PC) or the like can be used.

<4> Operation Method of the Device The circuit switching means 21 of the device is configured by, for example, switching SW1 to SW5. FIG. 4 shows states of the switching SW during solar cell power generation, opening, and preventive recovery work.

  When performing normal power generation, the ON / OFF state of SW1 to SW5 is as shown in FIG. 3, and SW1 and SW3 of the circuit switching means in the block diagram are turned ON, and SW2, SW4, and SW5 are turned OFF. ing. When the output of the solar cell is lowered due to the PID phenomenon, the output reduction of the solar cell whose output has been reduced is performed by operating the switching SW as follows. The switching operation of the switch SW of the circuit switching means is performed by the control means (PC).

1) Turn off all SWs and open the solar cell.
2) Next, when SW1 and SW3 are turned OFF and SW2, SW4 and SW5 are turned ON, the solar cell is disconnected from the PCS. Both the positive electrode and the negative electrode of the solar cell can be applied with a positive voltage by the power supply means 22. The frame of the solar cell module alone is usually grounded. However, in the circuit of the present device 20, the negative electrode of the power supply device is grounded by SW4.
3) After forming the state of 2), a positive voltage is applied to the positive electrode and the negative electrode of the solar cell by the power supply means 22. That is, a positive voltage is applied between the cells and wiring members inside the solar battery and the frame to generate an electric field.

  The apparatus 20 performs switching operation of the switching SW as described above by the circuit switching means to prevent and recover the output decrease of the solar cell. This device prevents and recovers the PID phenomenon by changing only the wiring system while the solar cell is installed. During the daytime and during solar power generation, the use of this device causes the positive and negative electrodes of the solar cells in each array to be short-circuited, and the power is consumed by heat generation inside the solar cells. In the verification, there was no need to measure particularly abnormal heat generation. Therefore, it is possible to prevent and recover output reduction regardless of whether it is irradiated with sunlight (daytime), at night, overcast, or rainy.

  As environmental conditions for operating this device, when the surface of the transparent substrate (glass plate) of the solar cell module is wet, the entire surface becomes an electrode, and a strong electric field is applied to the center of the module far from the frame. The output recovery by can be promoted. Therefore, the surface of the transparent substrate is wet in the dense fog state after rain or rain. It is desirable to operate this apparatus in such a state. The PID phenomenon has a high recovery speed at high temperatures. Therefore, it is desirable to operate this apparatus when the module temperature is high.

  A second embodiment will be described with reference to FIG. FIG. 5 is a block diagram of the output decrease prevention and recovery device according to the second embodiment. In this embodiment, a temperature detecting means 25 for detecting the temperature of the solar cell installation place and a humidity detecting means 26 for detecting the humidity are added to the first embodiment.

  The temperature detection means 25 is installed near the installation location of the solar cell. A known temperature sensor can be used as the temperature detecting means. Moreover, it can also be set as the structure which installs this temperature sensor in the solar cell module nearest, and detects the temperature of a solar cell module. Moreover, the humidity detection means 26 is installed near the installation place of a solar cell. A known humidity sensor can be used as the humidity detector.

  In addition to these, the solar radiation amount detecting means 27 may be provided. As a means for detecting the amount of solar radiation, a known solar radiation amount sensor can be used. Thereby, as described above, it is possible to confirm that the amount of solar radiation has become a certain amount or less during the daytime, and to operate the apparatus. Moreover, it can also be set as the structure which provided the humidity sensor 26 and the rainfall sensor 28 which detects the state of rainfall.

  The detection results obtained by the temperature detection means 25, the humidity detection means 26, the solar radiation amount detection means 27, and the rainfall sensor 28 are input to the PC as the control means in FIG. A program for determining the operation timing of each operation mode based on the operation modes of the present apparatus and the detection results of the temperature detection means, humidity detection means, solar radiation amount detection means, and rainfall sensor is set in advance in the PC. By operating the PC in this way, it is possible to minimize the power generation decrease of the solar cell power generation system and realize the optimum operation of the present apparatus. Thereby, the prevention of the PID phenomenon of the solar cell system and the preventive recovery of the output decrease due to the PID phenomenon can be unmanned, and the maintenance-free of the solar cell power generation system can be realized.

  Example 1 and Example 2 were the forms which always install the apparatus of this invention between a solar cell and PCS. However, when this device is always in a place different from the power conversion system of the solar cell power generation system and the PID phenomenon is likely to occur, or when the PID phenomenon occurs and the output of the solar cell decreases, this device Can be used in such a form that the apparatus is operated at the place and the apparatus is operated to perform the work for preventing and recovering the output decrease.

  In an actual solar cell power generation system, a plurality of solar cell arrays are connected in parallel to one PCS. Therefore, by increasing the electric capacity of each device of the present apparatus, it is possible to operate one of the present apparatus for a plurality of arrays to prevent and recover the output of the solar cell. Conversely, if it is intended to reduce the weight and size of the device itself, the device is operated with the electric capacity necessary to operate the device for one array of solar cell modules or a single solar cell module. It is also possible to configure.

  This apparatus can also be configured to easily change the connection unit, for example, by connecting the array of solar cell modules 1 connected to the PCS or the entire array in consideration of the electric capacity. Therefore, if it is a solar cell power generation system for home use, it can cope with a business trip as a lighter device, and if it is a mega solar class, it can respond to various uses such as a permanent installation of a large one.

  This device can also be built in the PCS. Since the PCS is a general-purpose PCS that does not normally limit the types of solar cells, it is not necessary to worry about the PID resistance of the solar cells as long as the PCS incorporates the function of this device. In the future, even if solar cells with high PID resistance become mainstream, it becomes possible to minimize the risk of occurrence of the PID phenomenon after installation of the solar cells. Further, as described in the third embodiment, it is possible to have the apparatus stand by at a place completely different from the solar cell system. Thereby, it is possible to retrofit the apparatus when PID occurs, or to temporarily connect and work on a business trip.

  This device can be realized at a lower cost than a method in which an insulation transformer is added to the PCS used in the solar battery power generation system and the negative electrode is grounded to prevent the occurrence of the PID phenomenon.

A Solar cell module array 10 Solar cell module 11 Transparent substrate (glass plate)
DESCRIPTION OF SYMBOLS 12 Back material 13 Filler 14 String 15 Electrode 16 Solar cell 17 Lead wire 18 Frame 19 Seal material 20 Output fall prevention recovery device 21 Circuit switching means 22 Power supply means 23 Grounding means 24 Control means (PC)
25 Temperature detection means 26 Humidity detection means 27 Solar radiation amount detection means 28 Rainfall sensor PCS Power conditioner SW1 to SW5 Switching SW

Claims (9)

An output reduction prevention and recovery device for a solar cell module installed outdoors,
Circuit switching means for switching between the power generation circuit and the output drop prevention and recovery device in units of the solar cell module alone or in an array unit consisting of a plurality of the solar cell modules;
Power supply means for applying a positive voltage inside the solar cell module;
Grounding means for grounding the solar cell module;
Having
The solar cell module output reduction preventive recovery apparatus characterized by the above-mentioned. In addition to the output reduction prevention recovery device,
Humidity detecting means for detecting the humidity of the installation atmosphere of the solar cell module;
Temperature detecting means for detecting the temperature of the installation atmosphere of the solar cell module;
Having
The output reduction prevention recovery apparatus of the solar cell module of Claim 1 characterized by the above-mentioned.   An output decrease prevention and recovery device for a solar cell module, wherein the output decrease prevention and recovery device according to claim 1 or 2 is installed in a power conversion system of a solar cell module.   The output reduction prevention / recovery device according to claim 1 is the installation location of the solar cell module when the output reduction of the installed solar cell module is found or when the installation location is found to be in an atmosphere state that causes the output reduction. An apparatus for preventing and recovering a decrease in the output of a solar cell module, which is installed in a solar cell module to prevent and recover the output of a solar cell module. A method for preventing and recovering a decrease in output of a solar cell module installed outdoors,
A step of switching the circuit between the power generation circuit and the output reduction prevention recovery device in units of the solar cell module alone or in an array unit consisting of a plurality of the solar cell modules;
Applying a positive voltage inside the solar cell module;
Grounding the solar cell module;
Having
A method for preventing and recovering an output decrease of the solar cell module. The output reduction prevention recovery method of the solar cell module according to claim 5,
further,
Detecting the humidity of the installation atmosphere of the solar cell module;
Detecting the temperature of the installation atmosphere of the solar cell module;
Having
A method for preventing and recovering a decrease in output of a solar cell module.   The solar cell module output reduction preventive recovery device according to claim 1, wherein a grounding means for grounding the solar cell module uses a frame of the solar cell module.   2. The apparatus for preventing and recovering output reduction of a solar cell module according to claim 1, wherein the grounding means for grounding the solar cell module uses a metal plate installed on a transparent substrate of the solar cell module. When the output reduction of the installed solar cell module is found or when it is found that it is in a state causing the output reduction, the output reduction prevention and recovery device according to claim 1 is installed at the installation location of the solar cell module, The method for preventing and recovering the output decrease of the solar cell module according to claim 5, wherein the output decrease preventive recovery for the solar cell module is performed.

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