JP5511622B2 - Solar cell module failure diagnosis apparatus and method - Google Patents

Description

  The present invention relates to a failure diagnosis apparatus and method for a solar cell module used in a photovoltaic power generation system.

  A solar power generation system, as a basic configuration, is a power conditioner including a solar battery composed of a plurality of solar cell modules connected in series, and an inverter device that converts DC power generated by the solar cell into AC power And. As a type of photovoltaic power generation system, not only power is supplied to an AC load in the system but also power can be supplied to an external commercial power system (distribution system) and AC in the system. There is a type that supplies power only to a load. In addition, the serial connection body of a some solar cell module is called a string.

  By the way, when a certain solar cell module in the string is damaged due to deterioration or abnormality, the power generation capability of the solar cell is reduced. However, in the solar power generation system, the output of the solar power generation system (that is, the output of the power conditioner) ) Is not noticed that the power generation capacity of the solar cell is reduced until the value drops below a predetermined value, so that the operation with the defective module still continues for a long time.

  The power generation capacity of a solar cell can be confirmed by measuring the amount of solar radiation, estimating the power generation capacity, and comparing the estimated value with the actual power generation capacity. It is only understood and a defective module cannot be specified. In other words, conventionally, since a failure diagnosis for identifying a defective module is performed after confirming a decrease in the power generation capability of the solar cell, the restoration of the system is greatly delayed.

  And in the identification of this defective module, at the place where the solar cell is installed, such as on the rooftop, it is necessary for the staff to visually check whether there is an abnormality in the appearance of each module and to measure the output voltage of each module. It takes time and effort, and there is a risk of electric shock. Furthermore, depending on the installation location, there is a problem that the work is a high place and there is a risk of dropping.

  In order to solve such a problem, for example, in Patent Document 1, in a photovoltaic power generation system in which a plurality of strings are connected in parallel to an input port of a power conditioner, an abnormal string affects the power generation amount of other strings. In order to prevent damage, a voltage detection device is attached to each solar cell module to periodically diagnose the failure of each solar cell module, and the string to which the faulty module is connected is disconnected from the system and the fault module is displayed. A method of displaying on a vessel has been proposed.

JP-A-7-177852

  However, since the method disclosed in Patent Document 1 only displays a failure diagnosis result on a display device, if the confirmation of the display device is delayed, the discovery of power generation abnormality will be delayed, and the restoration of the system will be greatly improved. Be late. In addition, when the method disclosed in Patent Document 1 is applied to a photovoltaic power generation system having one string, a failure diagnosis result is only displayed on a display device, and the same problem occurs.

  Furthermore, even in a photovoltaic power generation system including a plurality of strings, the power conditioner has a plurality of input ports, and the maximum power point for each string connected to each of the plurality of input ports can be followed. In the case of the type, it is not necessary to separate the abnormal string because the abnormal string does not cause a decrease in the power generation amount of the other strings.

  In addition, the method disclosed in Patent Document 1 requires load means for applying a predetermined load between the power supply output terminals of each string, and further compares the voltage with the voltage between the detection terminals at predetermined positions in the string. Therefore, it is necessary to reset the comparison value according to the type of module, the number of series connections, and the configuration of the photovoltaic power generation system, which is troublesome.

  For example, in the case of a crystalline solar cell, the voltage of one solar cell is about 0.7V. When the solar cell module is configured with 50 series of solar cells, the voltage per module is about 35V, but when the solar cell module is configured with 20 series of solar cells, the voltage per module is Is about 14V.

  For this reason, in the method of detecting a failure by causing a current to flow through the photocoupler using the fact that a voltage is generated between the positive electrode end and the negative electrode end of the module as shown in Patent Document 1 above, It is necessary to tune the apparatus so that a current flows, and furthermore, a current is kept flowing to the photocoupler although it is very small even at the time of diagnosis, so that a power generation loss occurs.

  The present invention has been made in view of the above, and it is possible to remotely and safely diagnose failure of individual solar cell modules regardless of the types of solar cell modules constituting the string, the number of serial connections, and the configuration of the photovoltaic power generation system. An object of the present invention is to obtain a solar cell module fault diagnosis apparatus and method that can be reliably implemented and cause a staff member to notice a found fault at an early stage to reduce power generation loss as a system.

  In order to solve the above-described problems and achieve the object, a fault diagnosis device for a solar cell module according to the present invention is a bypass provided in each solar cell module in a string constituting a solar cell of a solar power generation system. At the time of fault diagnosis in which a plurality of switching elements connected in parallel to each of the diodes, a voltage detector that detects the output voltage of the string, a display and a sound generation unit, and a power conditioner of the photovoltaic power generation system are stopped The first voltage value detected by the voltage detector when all of the plurality of switch elements are in a non-conducting state at the same time, and when all of the plurality of switch elements are individually in a conducting state one by one When there is a difference voltage that is 1 V or less in the difference voltage from each of the second voltage values detected by the voltage detector, the corresponding switch. The solar cell module device is connected is displayed on the display unit as faulty, characterized by comprising a failure diagnosis means for driving the sound generating means.

  According to the present invention, failure diagnosis can be performed for each solar cell module, and a solar cell module that has failed from a remote location without fail regardless of the type of solar cell module, the number of serial connections, or the configuration of the photovoltaic power generation system. Can be identified. In addition to displaying the failed module on the display unit, the buzzer is sounded, so that the staff can be made aware of the failure at an early stage, the early system repair is possible, and the power generation loss as a system can be reduced. . At this time, during power generation operation other than during failure diagnosis, all of the plurality of switch elements are in a non-conductive state at the same time, and the current flowing through the solar cell flows through a normal path consisting of the solar cell module and the bypass diode. There is an effect that no unnecessary power generation loss occurs in the solar cell during operation.

FIG. 1 is a system diagram illustrating a configuration example of a photovoltaic power generation system including a failure diagnosis apparatus for a solar cell module according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the principle of failure diagnosis according to this embodiment. FIG. 3 is a flowchart for explaining a failure diagnosis processing procedure (part 1) performed by the failure diagnosis apparatus for the solar cell module shown in FIG. FIG. 4 is a flowchart for explaining a failure diagnosis processing procedure (part 2) performed by the failure diagnosis apparatus for the solar cell module shown in FIG.

  Embodiments of a failure diagnosis apparatus and method for a solar cell module according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a system diagram illustrating a configuration example of a photovoltaic power generation system including a failure diagnosis apparatus for a solar cell module according to an embodiment of the present invention. In FIG. 1, a solar power generation system 1 includes a solar cell 2 disposed at a high place such as a rooftop and a power conditioner 3 disposed in a building or the like.

  The solar cell 2 is composed of a single string formed of a series connection body of a plurality of solar cell modules (eight solar cell modules 4-1 to 4-8 in the illustrated example). Each of the eight solar cell modules 4-1 to 4-8 is provided with bypass diodes 5-1 to 5-8 between the positive electrode end and the negative electrode end in order to cope with a local change in solar radiation. It has been. The anode terminal of the bypass diode is connected to the negative terminal of the solar cell module, and the cathode terminal is connected to the positive terminal of the solar cell module. The bypass diode is turned off when the corresponding solar cell module performs normal power generation, but is turned off when the output of the corresponding solar cell module decreases due to insufficient solar radiation. Serves to bypass modules.

  In this embodiment, in such a configuration of the solar cell 2, a switch which is one of the components of the failure diagnosis apparatus according to this embodiment has a one-to-one relationship with the bypass diodes 5-1 to 5-8. Elements 6-1 to 6-8 are connected in parallel. The switch elements 6-1 to 6-8 are accompanied by switch drive circuits 7-1 to 7-8, respectively. The switch elements 6-1 to 6-8 are transistors in the illustrated example, but may be small relays.

  The power conditioner 3 includes an inverter device 8. The positive electrode bus P and the negative electrode bus N of the solar cell 2 are respectively connected to the positive electrode input terminal and the negative electrode input terminal of the inverter device 8, and the smoothing capacitor 9 is connected between the positive electrode input terminal and the negative electrode input terminal of the inverter device 8. Yes. The smoothing capacitor 9 is charged by the DC power generated by the solar cell 2 according to the amount of solar radiation, and forms a DC power source between the positive input terminal and the negative input terminal of the inverter device 8. The inverter device 8 converts the power of the DC power source into AC power. The AC output of the inverter device 8 is supplied to an AC load 10 in the system via an AC bus 11 and also connected to a commercial power system (distribution system) 12.

  In the power conditioner 3, a voltage detector 13, a calculation unit 14, a control unit 15, and a notification unit 16, which are the remaining components of the failure diagnosis apparatus according to this embodiment, are provided. The notification unit 16 includes a display and a buzzer as sounding means. The voltage detector 13 detects the voltage across the smoothing capacitor 9 and outputs it to the calculation unit 14. As shown in FIGS. 3 and 4 to be described later, the calculation unit 14 first obtains a comparison reference value from the detection voltage of the voltage detector 13 taken in at the timing notified from the control unit 15, and then the comparison reference value. The voltage difference is calculated and given to the control unit 15.

  The control unit 15 includes a storage device for failure diagnosis. In the storage device, the identification codes of all the solar cell modules constituting the string are stored in advance in association with the corresponding switch elements.

  The control unit 15 uses the storage device to execute a failure diagnosis according to a procedure as shown in FIGS. An overview is shown. At the time of failure diagnosis, the control unit 15 stops the power conditioner 3 and individually controls the switch drive circuits 7-1 to 7-8, so that all the switch elements 6-1 to 6-8 are simultaneously performed. The non-conduction state (off state) and the switch elements 6-1 to 6-8 are turned on one by one and the operation unit 14 is notified of the respective states. After that, the difference voltage (one or all) input from the calculation unit 14 is taken into the storage device, and failure diagnosis of each module is performed based on the difference voltage. When the failure module is found, the control unit 15 reads the identification code of the corresponding failure module from the storage device, displays the identification code on the notification unit 16, and sounds the buzzer of the notification unit 16.

  The operation of the solar cell module failure diagnosis apparatus according to this embodiment will be described below. First, the basic concept of failure diagnosis will be described. Since the solar cell module has a configuration in which a plurality of solar cells are connected in series, a DC voltage of about 10 V to 40 V is generated between the positive electrode end and the negative electrode end when there is no load when there is no failure.

  The failure of the solar cell module includes an open failure and a short-circuit failure. In the solar cell 2 having a general configuration in which the switch elements (6-1 to 6-8) are not present, the open-failed solar cell module is a high-resistance body, and normally the corresponding bypass diode is turned on. Therefore, a potential difference corresponding to the forward voltage of the bypass diode is generated between the positive electrode end and the negative electrode end of the open-failed solar cell module due to the current flowing through the corresponding bypass diode.

  That is, the potential difference between the positive electrode end and the negative electrode end of the solar cell module in which the open failure has occurred is approximately 1 V or less, and no voltage of 1 V or more is generated. Assuming that this situation is equivalent to short-circuiting the positive electrode end and the negative electrode end, the solar cell module in which an open failure has occurred is not affected even if the positive electrode end and the negative electrode end of the module are short-circuited. There will be no change in the voltage between.

  Therefore, even if the positive electrode end and the negative electrode end of the solar cell module are short-circuited by the switch element, when the voltage is the same as before the short-circuit and there is no change, the solar cell module is determined to be a faulty module. .

  Next, a specific description will be given with reference to FIG. FIG. 2 is a diagram for explaining the principle of failure diagnosis according to this embodiment. FIG. 2 shows the output voltages of the eight solar cell modules 4-1 to 4-8, the detection voltage of the voltage detector 13, and the calculation result of the calculation unit 14 in each of the diagnostic times # 0 to # 8. Has been.

  In FIG. 2, in the diagnosis time # 0, the control unit 15 turns off all the eight switch elements 6-1 to 6-8 at the same time. In the diagnostic times # 1 to # 8, the control unit 15 turns on only one of the eight switch elements 6-1 to 6-8 in order to connect the positive electrode end and the negative electrode end of the corresponding solar cell module. Short circuit.

  For example, among the eight solar cell modules 4-1 to 4-8, the solar cell module 4-3 has an open failure, the output voltage is 0V, the other solar cell modules are healthy, and the output voltage is 30V to If it is 35V, the detection voltage of the voltage detector 13 at the diagnosis time # 0 is 224.5V. Next, in the diagnosis time # 1 in which only the switch element 6-1 is turned on, the output voltage of the solar cell module 4-1 in addition to the solar cell module 4-3 becomes 0 V, and the detection voltage of the voltage detector 13 is , 192.5V. Similarly, in the diagnosis time # 2 in which only the switch element 6-2 is turned on, in addition to the solar cell module 4-3, the output voltage of the solar cell module 4-2 becomes 0V, and the detection voltage of the voltage detector 13 is 193.5V. On the other hand, in the diagnosis time # 3 in which only the switch element 6-3 is turned on, only the output voltage of the solar cell module 4-3 is 0V, and the detected voltage of the voltage detector 13 is 224 without changing from the diagnosis time # 0. It remains at 5V. In the subsequent diagnostic times # 4 to # 8, in addition to the solar cell module 4-3, the output voltage of each individual solar cell module is 0V, and the detection voltage of the voltage detector 13 is 189.5V, 191. .5V, 194.5V, etc.

  That is, the change in the detection voltage of the voltage detector 13 at each of the diagnostic times # 1 to # 8 is monitored with respect to the detection voltage of the voltage detector 13 at the diagnostic time # 0, and Thus, if there is a diagnostic round in which the detection voltage of the voltage detector 13 has no change, it can be determined that the solar cell module at the diagnostic round has failed.

  Therefore, in this embodiment, the calculation unit 14 uses the detection voltage 224.5V of the voltage detector 13 at the diagnosis time # 0 as a comparison reference value, and the voltage detector 13 at each of the diagnosis times # 1 to # 8. The difference voltage between the detected voltage and the comparison reference value is calculated. When the diagnosis time when the difference voltage is 1 V or less is found, the control unit 15 determines that a failure has occurred in the solar cell module at the diagnosis time, causes the display to display the failure module, and displays a buzzer. It is made to sound so that a staff member can notice failure module detection early.

  Specifically, the failure diagnosis operation according to this embodiment is performed as shown in FIGS. 3 and 4, for example. 3 and 4 are flowcharts for explaining the failure diagnosis processing procedure (part 1 and part 2) performed by the solar cell module failure diagnosis apparatus shown in FIG. In FIG. 3 and FIG. 4, the step indicating the processing procedure is abbreviated as ST.

  In FIG. 3, in ST <b> 1, the control unit 15 turns off all the switch elements 6-1 to 6-8 at the same time, drives the power conditioner 3, and operates the solar power generation system 1. In the process of operating the solar power generation system 1, the control unit 15 determines whether or not the elapsed time from the start of operation has reached a predetermined time, or is there an instruction input for failure diagnosis from the outside The arrival of the failure diagnosis time is monitored depending on whether or not (ST2).

  When the failure diagnosis time comes (ST2; Yes), the controller 15 stops the power conditioner 3 with all the switch elements 6-1 to 6-8 turned off at the same time, and calculates the start of the failure diagnosis. This is notified to the unit 14 (ST3). When the calculation unit 14 receives the notification of failure diagnosis start, the calculation unit 14 takes in the detection voltage of the voltage detector 13 and holds it as a comparison reference value (ST4). If the output voltages of the eight solar cell modules 4-1 to 4-8 at the start of the failure diagnosis are, for example, as shown in the diagnosis time # 0 shown in FIG. The detection voltage 224.5V of the voltage detector 13 at the time # 0 is set as a comparison reference value.

  Next, the control unit 15 turns on only one switch element i when i = 1 to 8, and notifies the calculation unit 14 to that effect (ST5). When the calculation unit 14 receives a notification that one switch element i is turned on from the control unit 15, the calculation unit 14 takes in the detection voltage of the voltage detector 13, calculates a difference voltage between the detection voltage and the comparison reference value, Give (ST6). The control unit 15 determines whether or not the differential voltage received from the calculation unit 14 is 1 V or less (ST7).

  When the difference voltage is 1 V or less in ST7 (ST7: Yes), the control unit 15 causes the indicator of the notification unit 16 to display the identification code of the solar cell module for the switch element that is turned on, and at the same time, the notification unit 16 The buzzer is sounded (ST8), and the process proceeds to ST9. On the other hand, if the difference voltage is not 1 V or less in ST7 (ST7: No), the control unit 15 proceeds directly to ST9.

  In ST9, the control unit 15 determines whether or not an ON operation has been performed for all the switch elements. The control unit 15 repeats the processes of ST5 to ST9 until the ON operation is finished for all the switch elements (ST9: No). In the meantime, in the example shown in FIG. 2, the failed solar cell module 4-3 is detected in the diagnosis time # 3 when the switch element 6-3 is turned on, and the failure module 4 is notified from the notification unit 16 to the attendant. -3 identification code display and buzzer sound.

  When the ON operation is completed for all the switch elements (ST9: Yes), the control unit 15 displays the end of the failure diagnosis on the display unit of the notification unit 16 and determines whether there is a failure module. (ST10). If there is no failure module (ST10: No), the control unit 15 returns directly to ST1 and restarts the system operation. On the other hand, if there is a faulty module (ST10: Yes), the control unit 15 confirms that there is an input of operation OK from the staff member after the module replacement (ST11: Yes), and then returns to ST1 to return to the system. Resume operation.

  Next, FIG. 4 shows an operation example when the storage device included in the control unit 15 has a margin. That is, in FIG. 4, in ST20 after the processing of ST1 to ST6 described in FIG. 3, the control unit 15 stores the sequence number of the switch element that is turned on and the difference voltage input from the calculation unit 14 in association with each other. Store in the device. And the control part 15 repeats the process of ST5, ST6, and ST20 until it complete | finishes ON operation about all the switch elements (ST21: No).

  When the control unit 15 finishes the ON operation for all the switch elements (ST21: Yes), all the sequence numbers of the switch elements that are turned on and all the differential voltages input from the calculation unit 14 are stored in association with each other. In the stored memory device, the presence or absence of a switch element having a differential voltage of 1 V or less is examined (ST22).

  As a result, when there is a switch element whose differential voltage is 1 V or less (ST22: Yes), the control unit 15 displays the identification code of the solar cell module for the switch element on the display unit of the notification unit 16 and simultaneously notifies. The buzzer of the unit 16 is sounded (ST23), and the process proceeds to ST24. On the other hand, if there is no switch element having a difference voltage of 1 V or less in ST22 (ST22: No), the control unit 15 proceeds directly to ST24.

  In ST24, the control unit 15 displays the end of the failure diagnosis on the display unit of the notification unit 16, and determines whether or not there is a failure module. When there is no failure module (ST24: No), the control unit 15 returns directly to ST1 and restarts the system operation. On the other hand, if there is a faulty module (ST24: Yes), the control unit 15 confirms that there is an input of operation OK from the staff after the module replacement (ST25: Yes), and then returns to ST1 to return to the system. Resume operation.

  In the photovoltaic power generation system in which a plurality of strings are connected in parallel to the input port of the inverter device, the fault diagnosis for each string is performed by switching the connection between the output terminal of each string and the voltage detector with a switch. Or the procedure shown in FIG.

  Although not shown in FIG. 4, the control unit 15 can also store time information at the time of failure diagnosis in the storage device, and store the stored contents (difference voltage and time information of all modules) at an appropriate time. It can be transmitted to an external monitor device. As a result, the history of each solar cell module can be taken, and materials for determining the replacement time of the solar cell module can be obtained.

  As described above, according to this embodiment, a switch element is connected in parallel to each of the bypass diodes provided in each solar cell module constituting the string, and all of the plurality of switch elements are simultaneously non-conductive. The output voltage (first voltage value) of the string when in the state (off state) and the output voltage of the string when all of the plurality of switch elements are individually in the conductive state (on state) ( When there is a difference voltage that is 1 V or less among the difference voltages from each of the second voltage values), it is determined that the solar cell module to which the corresponding switch element is connected has failed. Failure diagnosis can be performed for each piece, and solar power that has failed safely and securely from a remote location, regardless of the type of solar cell module, the number of series connections, or the configuration of the photovoltaic power generation system. Perform a particular module.

  In addition to displaying the failed module on the display unit, the buzzer is sounded, so that the staff can be made aware of the failure at an early stage, the early system repair is possible, and the power generation loss as a system can be reduced. .

  Furthermore, since a failure is discovered at the time of a plurality of failure diagnoses, it is possible to specify at which stage the failure has occurred.

  At this time, during power generation operation other than during failure diagnosis, all of the plurality of switch elements are in a non-conductive state at the same time, and the current flowing through the solar cell flows through a normal path consisting of the solar cell module and the bypass diode. No unnecessary power generation loss occurs in the battery.

  In addition, the effect that the open circuit voltage for every solar cell module can be confirmed remotely is also acquired using the several switch element connected in parallel with each of the bypass diode.

  In the above embodiment, an example in which only one bypass diode is provided in the solar cell module, that is, the anode terminal of the bypass diode is connected to the negative terminal of the solar cell module, and the cathode terminal is the positive terminal of the solar cell module. Shown when connected extremely. However, in one solar cell module, many configurations are known in which solar cells connected in series are divided into several blocks and a bypass diode is provided for each block. In the case of a configuration having a plurality of bypass diodes in such a single solar cell module, the same effect as that of the above-described embodiment can be achieved by the configuration in which the switch elements are connected in parallel to each bypass diode. it can.

  As described above, the failure diagnosis apparatus and method for a solar cell module according to the present invention is independent of the types of solar cell modules constituting the string, the number of series connections, and the configuration of the solar power generation system. The present invention is useful as a failure diagnosis apparatus and method for a solar cell module that can perform failure diagnosis from a remote location, make a discovered failure early noticeable, and reduce power generation loss as a system.

DESCRIPTION OF SYMBOLS 1 Photovoltaic power generation system 2 Solar cell 3 Power conditioner 4-1 to 4-8 Solar cell module which comprises a string 5-1 to 5-8 Bypass diode 6-1 to 6-8 Switch element 7-1 to 7- 8 Switch Drive Circuit 8 Inverter Device 9 Smoothing Capacitor 10 AC Load 11 AC Bus 12 Commercial Power System (Distribution System)
13 Voltage detector 14 Calculation unit 15 Control unit 16 Notification unit (display, buzzer)
P Positive bus N N Negative bus

Claims (9)

A plurality of switch elements connected in parallel to each of the bypass diodes provided in each solar cell module in the string constituting the solar cell of the solar power generation system;
A voltage detector for detecting an output voltage of the string;
An indicator and pronunciation means;
A first voltage value detected by the voltage detector when all of the plurality of switch elements are in a non-conducting state at the time of failure diagnosis when the power conditioner of the photovoltaic power generation system is stopped; and The corresponding switch when there is a difference voltage of 1 V or less in the difference voltage from each of the second voltage values detected by the voltage detector when all of the switch elements are individually turned on one by one. A failure diagnosis device for a solar cell module, comprising: failure diagnosis means for displaying on the display that the solar cell module to which the element is connected is broken and driving the sound generation means. The failure diagnosis means includes
A calculation unit that calculates a difference between each of the first voltage value and the second voltage value, and sequentially outputs each difference voltage;
At the start of the fault diagnosis, all of the plurality of switch elements are simultaneously controlled to be in a non-conductive state, and thereafter, the control is performed so that all of the plurality of switch elements are individually turned on one by one. Each time the difference voltage is input from the calculation unit, it is determined whether or not the difference voltage is 1V or less. If the difference voltage is 1V or less, the solar cell module to which the corresponding switch element is connected fails. The solar cell module failure diagnosis apparatus according to claim 1, further comprising: a control unit that displays on the display and drives the sound generation means. The failure diagnosis means includes
A calculation unit that calculates a difference between each of the first voltage value and the second voltage value, and sequentially outputs each difference voltage;
At the start of the fault diagnosis, all of the plurality of switch elements are simultaneously controlled to be in a non-conductive state, and thereafter, the control is performed so that all of the plurality of switch elements are individually turned on one by one. All the differential voltages input from the calculation unit are stored, and when there is a differential voltage of 1 V or less among the stored differential voltages, the solar cell module to which the corresponding switch element is connected is considered to be faulty. The failure diagnosis apparatus for a solar cell module according to claim 1, further comprising: a control unit that displays on a display unit and drives the sound generation unit. At the time of the failure diagnosis,
The failure diagnosis device for a solar cell module according to any one of claims 1 to 3, wherein the solar cell module failure diagnosis device is any time after the start of operation of the solar power generation system or when an external instruction is given. . The controller is
The time information of the date and time when the failure diagnosis is performed is stored when all the differential voltages input from the arithmetic unit are stored, and the stored contents are transmitted to an external host device. The failure diagnosis device for a solar cell module according to 1. At the time of failure diagnosis when the power conditioner of the photovoltaic power generation system is stopped,
At the start of the fault diagnosis, all of the plurality of switch elements connected in parallel to each of the bypass diodes provided in each solar cell module in the string constituting the solar cell of the solar power generation system are simultaneously turned off. A first step of controlling to a state and obtaining an output voltage of the string at that time as a comparison reference value;
Thereafter, controlling one of the plurality of switch elements to a conductive state and determining whether or not a difference voltage between the output voltage of the string and the comparison reference value is 1 V or less, A second step performed for all of the plurality of switch elements;
As a result of the determination, when the difference voltage is 1 V or less, the solar cell module to which the corresponding switch element is connected is displayed on the display unit as having failed, and a third step of driving the sound generation means is performed. A failure diagnosis method for a solar cell module, comprising: At the time of failure diagnosis when the power conditioner of the photovoltaic power generation system is stopped,
At the start of the fault diagnosis, all of the plurality of switch elements connected in parallel to each of the bypass diodes provided in each solar cell module in the string constituting the solar cell of the solar power generation system are simultaneously turned off. A first step of controlling to a state and obtaining an output voltage of the string at that time as a comparison reference value;
Thereafter, one of the plurality of switch elements is controlled to be in a conductive state, and a difference voltage between the output voltage of the string and the comparison reference value at that time is stored in a storage device. A second step to be carried out for all;
When there is a difference voltage of 1V or less in the stored difference voltage, the solar cell module to which the corresponding switch element is connected is displayed on the display unit as being broken, and the sound generation means is driven. A failure diagnosis method for a solar cell module comprising the steps of: At the time of the failure diagnosis,
The failure diagnosis method for a solar cell module according to claim 6 or 7, characterized in that it is an arbitrary time after the start of operation of the solar power generation system or an external instruction. In the second step,
The method of claim 7, further comprising: storing time information of the date and time when the failure diagnosis is performed when storing all the differential voltages, and further transmitting the stored contents to an external host device. The fault diagnosis method of the described solar cell module.

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