Power supply system

Abstract

Provided is a power supply system (1, 201, 301) capable of quickly extinguishing an arc when an arc discharge occurs. The present invention is provided with: a power supply module (2); a converter unit (10) having a booster circuit in which reactor units (L1, L2) and a first switching element (Q1) are connected in series, and a rectifier unit (D1) that allows the flow of current from the converter circuit side to the inverter unit side and blocks the flow of current from the inverter unit side to the converter circuit side; an inverter unit (11) having cutoff units (Q2-Q5); a series arc detection unit (5); and connection terminals (22, 23) capable of performing a transformation operation for switching the on-state and off-state of the first switching element (Q1), increasing or decreasing the input voltage of the power supply module (2), and outputting power to the inverter unit (11), the connection terminals (22, 23) being configured so that when the series arc detection unit (5) detects a series arc discharge, the connection terminals (22, 23) switch between the on-state and off-state of the first switching element (Q1), and the connection terminals (22, 23) are connected to the inverter unit (11). The first switching element (Q1) is kept in an OFF state, and the flow of power flowing between the converter unit (10) and the connection terminals (22, 23) is cut off by a cut-off unit (Q2-Q5) or a rectifying unit (D1).

Description

Technical Field

[0001] The present invention relates to a power supply system including a power supply module such as a solar cell module and a power conversion device. Background Art

[0002] Conventionally, a solar power generation system includes a solar cell module and a power conditioner, and the power conditioner can convert the DC power generated by the solar cell module into AC power and supply the AC power to a commercial power supply system.

[0003] In conventional solar power generation systems, fires occasionally occur several years after installation. The main causes of such fires are often cable clamping during construction, cable damage, poor contact at the connector, and arc discharges caused by years of degradation.

[0004] This arc discharge can be roughly classified into series arc discharge and parallel arc discharge according to where it occurs on the circuit.

[0005] A series arc discharge is an arc discharge generated when a current passes through a conductor in a series circuit, and a parallel arc discharge is an arc discharge generated when a current passes between two conductors connected in parallel in a parallel circuit.

[0006] These arc discharges need to be extinguished quickly when they occur.

[0007] Therefore, in the solar power generation system of Patent Document 1, a circuit breaker for interrupting arc discharge is provided between the solar cell module and the power conditioner, and when series arc discharge is detected, the circuit breaker interrupts the arc discharge to rapidly extinguish the arc discharge.

[0008] Furthermore, the power conditioner of Patent Document 2 measures the input current and output current of the DC / AC inverter, creates a calculation signal based on these, and performs calculation based on the calculation signal to determine the presence or absence of arc discharge.

[0009] Furthermore, in the power conditioner of Patent Document 2, when it is determined that arc discharge has occurred, an operation of cutting off the power supply from the solar power generation unit and an operation of cutting off the connection with the commercial power supply system are executed.

[0010] Patent Document 1: Japanese Patent No. 6597394

[0011] Patent Document 2: Japanese Patent Application Publication No. 2020-36511

[0012] However, in a typical power conditioner, the DC power generated by the solar cell module is boosted by a DC / DC converter, and the boosted DC power is converted into AC power by a DC / AC converter and output to a commercial power supply system.

[0013] It is desirable to cope with the above-mentioned arc discharge while maintaining the function of such a power conditioner and not making a major change in the structure of the power conditioner so as to cope with the arc discharge.

[0014] Arc discharge can be classified into arc discharge that is highly dangerous and likely to cause fire due to long-term generation, and arc discharge that is less dangerous and less likely to cause fire due to short-term extinguishing.

[0015] When arc discharge occurs, it is preferable to be able to determine the danger of arc discharge without making major changes to the structure of the power conditioner while maintaining the function as the power conditioner, because this makes it easier to cope with the arc discharge when it occurs. Summary of the invention

[0016] Therefore, an object of the present invention is to provide a power supply system capable of quickly extinguishing an arc when an arc discharge occurs. Another object of the present invention is to provide a power supply system capable of determining the danger of an arc discharge when an arc discharge occurs.

[0017] One embodiment of the present invention for solving the above-mentioned problems is a power supply system, comprising a power supply module, a power conversion device and a series arc detection unit, wherein the power conversion device comprises a converter unit, an inverter unit and a connection terminal that can be electrically connected to a system power supply unit, the converter unit comprises a converter circuit in which a reactor unit and a first switching element are connected in series, and can perform a voltage transformation operation, which steps up or steps down an input voltage from the power supply module by switching an on state and an off state of the first switching element, and outputs power to the inverter unit, and the converter unit comprises a rectifier unit that allows a current to flow from the converter circuit side to the inverter unit side. The inverter unit includes a cut-off unit capable of cutting off the power supply from the inverter unit to the connection terminal side. The series arc detection unit is capable of detecting series arc discharge at a portion closer to the power supply module side than the power conversion device. When the series arc detection unit detects series arc discharge, a series arc cut-off action is performed, which stops the voltage transformation action, keeps the disconnected state of the first switching element unchanged or changes to the disconnected state and maintains it, and cuts off the flow of power flowing between the converter unit and the connection terminal through the cut-off unit or the rectifier unit.

[0018] According to this method, when a series arc discharge is detected and the voltage on the converter circuit side based on the rectifier unit is the same as or greater than the voltage on the inverter unit side, the first switching element is placed in an off state, and the flow of power flowing between the converter unit and the connection terminal is cut off by the cut-off unit, thereby preventing a short circuit between the positive and negative sides of the power supply module. There is no need to provide a circuit breaker between the power supply module and the power conversion device, and even if the overall system is not enlarged, the arc can be quickly extinguished when a series arc discharge occurs.

[0019] On the other hand, when a series arc discharge is detected and the voltage on the converter circuit side is smaller than the voltage on the inverter side with the rectifier as a reference, the current does not flow from the converter circuit side to the inverter side through the rectifier, and the flow of power flowing between the converter part and the connection terminal is cut off. Therefore, by making the first switching element in the off state, a short circuit between the positive and negative sides of the power supply module can be prevented. There is no need to provide a circuit breaker between the power supply module and the power conversion device, and even if the overall system is not enlarged, the arc can be extinguished quickly when a series arc discharge occurs.

[0020] A preferred embodiment is that the converter unit is a boost converter unit, the converter circuit is a boost circuit, the boost converter unit is capable of performing a boost action, the boost action boosts the input voltage from the power supply module by switching the on state and the off state of the first switching element, and outputs power to the inverter unit, and when the series arc detection unit detects a series arc discharge, the series arc cutoff action stops the boost action, and keeps the first switching element in the off state unchanged or changes to the off state and maintains it, and cuts off the flow of power flowing between the boost converter unit and the connection terminal by the cutoff unit or the rectifier unit.

[0021] A preferred embodiment is to have a parallel arc detection unit, which detects parallel arc discharge at a portion closer to the power supply module than the power conversion device. When the parallel arc detection unit detects parallel arc discharge, a parallel arc cutting action is performed, which stops the boosting action and keeps the first switching element in the on state unchanged or changes to and maintains the on state.

[0022] In a preferred embodiment, the boost converter unit includes a capacitor unit, and the capacitor unit is connected in parallel to the first switching element.

[0023] Furthermore, conventionally, when arc discharge occurs, maintenance is immediately performed.

[0024] However, if the arc discharge can be extinguished at an early stage, the occurrence of the arc discharge will not cause a fire in most cases, and the system can continue to be used.

[0025] Therefore, in a preferred embodiment, the voltage step-up operation is restarted when a predetermined time has passed since the series arc detection unit detected the series arc discharge.

[0026] Here, once a series arc discharge occurs, it often continues to occur. If the series arc discharge occurs frequently, there is a high possibility that a problem will occur in the system.

[0027] Therefore, in a preferred embodiment, when the series arc interruption operation is performed a predetermined number of times or more, an operation stopping operation of stopping the operation of the power conversion device is performed.

[0028] In a preferred embodiment, the voltage step-up operation is restarted when a predetermined time has passed since the parallel arc detection unit detected the parallel arc discharge.

[0029] In a preferred embodiment, when the parallel arc interruption operation is performed a predetermined number of times or more, an operation stopping operation of stopping the operation of the power conversion device is performed.

[0030] However, if the power conversion device is stopped for a relatively long period of time, the arc discharge on the power supply module side is often also converged.

[0031] Therefore, in a preferred embodiment, the operation stop operation is terminated when a predetermined period of time has elapsed since the execution of the operation stop operation.

[0032] A preferred embodiment is that the inverter unit has a second switching element, a third switching element, a fourth switching element and a fifth switching element, and the inverter unit has a full-bridge circuit in which the second switching element and the fifth switching element, and the third switching element and the fourth switching element are respectively arranged at diagonals, and when the series arc detection unit detects series arc discharge, the flow of power flowing between the boost converter unit and the connection terminal is cut off by making at least one of the combination of the second switching element and the third switching element and the combination of the fourth switching element and the fifth switching element an off state.

[0033] Preferably, the power supply module is at least one module selected from a solar cell module, a fuel cell module, and a power storage module.

[0034] A preferred embodiment is that there are multiple power supply modules, the power conversion device has multiple boost converter units, the multiple boost converter units are electrically connected to the multiple power supply modules, respectively, the series arc detection unit can respectively detect series arc discharges in the parts closer to each power supply module than the power conversion device, and when the series arc detection unit detects series arc discharges in the part on the side of one power supply module, and in the boost converter unit corresponding to the one power supply module, the voltage on the boost circuit side is smaller than the voltage on the inverter side based on the rectifier unit, in the boost converter unit corresponding to the one power supply module, the boost action is stopped, and the first switching element is kept in the disconnected state or is changed to the disconnected state and maintained, and the boost action is continued in the boost converter units corresponding to other power supply modules.

[0035] According to this aspect, even if a series arc discharge occurs in one power supply module, the operation of the other power supply modules can be continued.

[0036] A preferred embodiment is to have a power supply module, a power conversion device, a first wiring portion electrically connecting the power supply module and the power conversion device, and an arc detection unit, wherein the arc detection unit can detect arc discharge of the first wiring portion without contacting the first wiring portion, and when the arc detection unit detects arc discharge, a hazard determination action is performed, which compares the duration of the arc discharge from the detection of the arc discharge with a first threshold value, and determines whether the generated arc discharge reaches a first benchmark related to hazard based on the result of the comparison with the first threshold value.

[0037] A preferred method is that, when the result of comparing the above-mentioned duration with the above-mentioned first threshold is that the generated arc discharge is not judged to have reached the above-mentioned first benchmark, the above-mentioned hazard level judgment action compares the risk judgment work amount with a pre-set second threshold, and judges whether the generated arc discharge reaches a second benchmark related to the hazard based on the result of comparison with the above-mentioned second threshold, and the above-mentioned risk judgment work amount is calculated based on the current setting value corresponding to the output of the above-mentioned power supply module, the voltage setting value based on the voltage when the arc discharge is generated, and the above-mentioned duration.

[0038] Preferably, the current setting value, the voltage setting value, and the second threshold value are set based on information input by an information input unit that receives information input from a user or information transmitted from an external device.

[0039] One embodiment of the present invention is a power supply system, which includes a power supply module, a power conversion device, a first wiring portion electrically connecting the power supply module and the power conversion device, and an arc detection unit, wherein the arc detection unit can detect arc discharge of the first wiring portion without contacting the first wiring portion, and when the arc detection unit detects arc discharge, a hazard determination action is performed, which compares the duration of the arc discharge from the detection of the arc discharge with a first threshold value, and determines whether the generated arc discharge reaches a first benchmark related to hazard based on the result of the comparison with the first threshold value.

[0040] According to this method, the arc detection unit can obtain the presence or absence of arc discharge in the first wiring part and the duration of arc discharge when arc discharge occurs without contacting the first wiring part, and the arc detection unit can be easily installed. In addition, it is possible to determine whether the generated arc discharge is a highly dangerous (large-scale) arc discharge such as a fire by a simple structure, so that appropriate response can be taken to the generated arc discharge.

[0041] One embodiment of the present invention is a power supply system, which has a power generation module, a power conversion device, a power storage module, a bidirectional converter unit and an arc detection unit, and has a first wiring unit electrically connecting the above-mentioned power generation module with the above-mentioned power conversion device, a second wiring unit electrically connecting the above-mentioned power storage module with the above-mentioned bidirectional converter unit, and a third wiring unit electrically connecting the above-mentioned bidirectional converter unit with the above-mentioned power conversion device. The above-mentioned arc detection unit can detect arc discharge of the above-mentioned one wiring unit in a manner not to contact at least one wiring unit selected from the above-mentioned first wiring unit, the above-mentioned second wiring unit and the above-mentioned third wiring unit. When the above-mentioned arc detection unit detects arc discharge in the above-mentioned one wiring unit, a hazard determination action is performed, and the hazard determination action compares the duration from the detection of the above-mentioned arc discharge in the above-mentioned one wiring unit to the extinction of the above-mentioned arc discharge with a first threshold value, and judges whether the generated arc discharge reaches a first benchmark related to hazard based on the result of comparison with the above-mentioned first threshold value.

[0042] In this method, the arc detection unit can obtain the presence or absence of arc discharge in the wiring part as the target and the time when the arc discharge occurs without contacting the wiring part as the target, and the arc detection unit can be easily installed. In addition, it is possible to judge whether the arc discharge generated is a high-risk (large-scale) arc discharge such as a fire by a simple structure, so that appropriate measures can be taken against the generated arc discharge.

[0043] According to the power supply system of the present invention, when arc discharge occurs, the arc can be extinguished quickly.

[0044] According to the power supply system of the present invention, when arc discharge occurs, it is possible to determine the danger of the arc discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is an explanatory diagram of a power supply system according to a first embodiment of the present invention, Figure 1 (a) is a block diagram of the power supply system. Figure 1 (b) is a circuit diagram of the power supply system.

[0046] Figure 2 yes Figure 1 Flow chart of the operation of the power supply system.

[0047] Figure 3 yes Figure 1 Flow chart of the series shutdown of the power supply system.

[0048] Figure 4 It is a circuit diagram of a power supply system according to a second embodiment of the present invention.

[0049] Figure 5 It is a block diagram schematically showing a power supply system according to a third embodiment of the present invention.

[0050] Figure 6 Yes means Figure 5 Block diagram of a portion of a power supply system.

[0051] Figure 7 Yes means Figure 5 Flowchart of the danger identification actions performed by the power supply system.

[0052] Figure 8 yes Figure 5 Flow chart of the arc cutting action.

[0053] Fig. 9 This is a flow chart of a power supply system during a series stop operation according to another embodiment of the present invention. DETAILED DESCRIPTION

[0054] Hereinafter, embodiments of the present invention will be described in detail.

[0055] like Figure 1 As shown in FIG. 1 ( a ), the power supply system 1 according to the first embodiment of the present invention includes a power supply module 2 , a power conversion device 3 , a series arc detection unit 5 , a parallel arc detection unit 6 , and a control unit 7 .

[0056] The power supply system 1 supplies the DC power generated by the power supply module 2 to the power conversion device 3 , converts the DC power into AC power by the power conversion device 3 , and supplies the AC power to the system power supply unit 100 .

[0057] (Power supply module 2)

[0058] The power supply module 2 is a power generation module that generates power using renewable energy such as a solar cell module or a fuel cell module, or a power storage module such as a secondary battery module. In the present embodiment, the power generation module, specifically a solar cell module, is used.

[0059] The power supply module 2 is formed by connecting a plurality of solar cell strings in parallel, and each solar cell string has a plurality of solar cell units connected in series.

[0060] (Power conversion device 3)

[0061] like Figure 1 As shown in FIG. 2( b ), the power conversion device 3 includes a boost converter unit 10 (converter unit), an inverter unit 11 , module-side connection terminals 20 ( 20 a , 20 b ), and system-side connection terminals 22 , 23 .

[0062] (Boost Converter Unit 10)

[0063] like Figure 1 As shown in (b) of FIG. 1 , the boost converter unit 10 is connected to the power supply module 2 via the positive electrode side input terminal 20 a and the negative electrode side input terminal 20 b .

[0064] The boost converter unit 10 is a non-insulated DC-DC converter including a reactor unit L1 , a switching element Q1 , a diode unit D1 (rectifier unit), and a capacitor unit C1 .

[0065] The boost converter unit 10 is a so-called chopper-type DC-DC converter.

[0066] The boost converter unit 10 includes a boost circuit (converter circuit) in which a positive-side input terminal 20a, a reactor unit L1, a switching element Q1, and a negative-side input terminal 20b are connected in series, and switches the on state and the off state of the switching element Q1 according to a PWM control signal from the control unit 7, thereby boosting (transforming) the voltage.

[0067] That is, the boost converter unit 10 turns on the switching element Q1 so that the boost circuit forms a closed loop to store energy in the reactor unit L1 , and turns off the switching element Q1 so that the boost circuit forms an open loop to release the energy stored in the reactor unit L1 .

[0068] In addition, the boost converter unit 10 can boost the voltage to a desired voltage by controlling the duty ratio according to the PWM control signal from the control unit 7 .

[0069] The boost converter unit 10 has a positive input terminal 20 a , a reactor unit L1 , a diode unit D1 , a capacitor unit C1 , and a negative input terminal 20 b connected in series, and a switching element Q1 connected in parallel to the diode unit D1 and the capacitor unit C1 .

[0070] The switching element Q1 can be switched between an on state and an off state according to a PWM control signal from the control unit 7 , and a transistor such as a bipolar transistor, a field effect transistor, an IGBT (insulated gate bipolar transistor), or a relay switch can be used.

[0071] The diode unit D1 is a rectifying unit that rectifies current in one direction, allows current to flow from the boost circuit side to the inverter unit 11 side, and can block current from flowing from the inverter unit 11 side to the boost circuit side.

[0072] In the boost converter unit 10 , a diode unit D10 is connected in parallel with the switching element Q1 .

[0073] The diode portion D10 allows the flow of a current in a direction opposite to the flow of a current in the on-state of the switching element Q1 , and can block the flow of a current in the same direction.

[0074] That is, the diode unit D10 is a rectifying unit that rectifies the current in one direction, allowing the current to flow from the negative input terminal 20b side to the positive input terminal 20a side, and can cut off the current flow from the positive input terminal 20a side to the negative input terminal 20b side.

[0075] (Inverter Unit 11)

[0076] The inverter unit 11 is a part that alternately converts DC power and AC power.

[0077] like Figure 1 As shown in (b) of FIG. 8 , the inverter unit 11 is connected to the system power supply unit 100 via the system side connection terminal 22 (connection terminal) and the system side connection terminal 23 (connection terminal).

[0078] The inverter unit 11 has a full-bridge circuit, which is a circuit in which switching elements Q2, Q5 and switching elements Q3, Q4 are respectively arranged at diagonals, including a first arm in which switching element Q2 and switching element Q4 are connected in series and a second arm in which switching element Q3 and switching element Q5 are connected in series, the first arm and the second arm are connected in parallel, and AC power is output from the midpoint of the first arm and the midpoint of the second arm.

[0079] For the inverter unit 11, when the system-side connection terminals 22 and 23 are connected to the system power supply unit 100, the switching element Q2, the reactor unit L2, the system power supply unit 100 and the switching element Q5 are connected in series, and the switching element Q3, the system power supply unit 100, the reactor unit L2 and the switching element Q4 are connected in series.

[0080] The inverter unit 11 constitutes a cutoff unit that cuts off the electric power input from the boost converter unit 10 using the switching elements Q2 to Q5 .

[0081] That is, the inverter unit 11 can cut off the flow of power from the boost converter unit 10 side to the system side connection terminals 22, 23 side by setting the switching elements Q2, Q3 on the positive side of the power supply module 2 and / or the switching elements Q4, Q5 on the negative side of the power supply module 2 to the disconnected state.

[0082] The switching elements Q2 to Q5 can be switched between an on state and an off state according to a PWM control signal from the control unit 7 , and transistors such as bipolar transistors, field effect transistors, IGBTs (insulated gate bipolar transistors), and relay switches can be used.

[0083] In the inverter unit 11 , diode units D2 to D5 are connected in parallel with the switching elements Q2 to Q5 .

[0084] The diode units D2 to D5 can allow the flow of a current in a direction opposite to the flow of a current in the on-state of the switching elements Q2 to Q5 , respectively, and can block the flow of a current in the same direction.

[0085] The inverter unit 11 can perform a power conversion operation of converting DC power into AC power according to the on-off cycle of each switching element Q2 to Q5 based on a PWM control signal from the control unit 7 .

[0086] (Series arc detection unit 5)

[0087] The series arc detection unit 5 is a portion that detects when a series arc discharge occurs at a portion closer to the power supply module 2 than the input terminals 20 a and 20 b of the power conversion device 3 .

[0088] That is, the series arc detection unit 5 detects series arc discharge not only on the power supply module 2 but also on the wiring connecting the power supply module 2 and the input terminals 20 a and 20 b .

[0089] (Parallel arc detection unit 6)

[0090] The parallel arc detection unit 6 is a portion that detects when a parallel arc discharge occurs at a portion closer to the power supply module 2 than the input terminals 20 a and 20 b of the power conversion device 3 .

[0091] That is, the parallel arc detection unit 6 detects parallel arc discharge not only on the power supply module 2 but also on the wiring connecting the power supply module 2 and the input terminals 20 a and 20 b .

[0092] (Control Unit 7)

[0093] The control unit 7 has a computer as a hardware structure, which includes: a central processing unit composed of a control device for controlling each device and a computing device for computing data; a storage device for storing data; an input device for inputting data from the outside; and an output device for outputting data to the outside.

[0094] That is, the control unit 7 can send and receive signals with an external computer (server, upper control device), and can store information sent from the external computer. Furthermore, through an information input unit (keyboard, pointing device, remote controller, touch panel, etc.) that accepts input of information from the user, the user can input information and can store the input information.

[0095] The control unit 7 is a part that includes a PWM circuit and can generate a PWM control signal, and is a part that can change each of the switching elements Q1 to Q5 between an on state and an off state by sending a PWM control signal to each of the switching elements Q1 to Q5.

[0096] Next, use Figure 2 The operation of the power supply system 1 is described with reference to the flowchart of FIG.

[0097] During normal operation, when series arc discharge or parallel arc discharge is detected, the power supply system 1 operates to extinguish the arc.

[0098] Specifically, first, Figure 2 As shown, the counter m and the counter n are reset (step S1-1), and normal operation is performed (step S1-2).

[0099] At this time, during normal operation, the power conversion device 3 performs power conversion action (boosting action, transformation action), that is, by periodically switching the on state and off state of the first switching element Q1 of the boost converter unit 10, the input voltage from the power supply module 2 is boosted (transformed), and DC power is output to the inverter unit 11. By switching the on state and off state of the switching elements Q2~Q5 of the inverter unit 11, the DC power input from the boost converter unit 10 is converted into AC power.

[0100] Next, it is determined whether the series arc detection unit 5 has detected a series arc discharge (step S1-3). If no series arc discharge is detected (No in step S1-3), it is determined whether the parallel arc detection unit 6 has detected a parallel arc discharge (step S1-4).

[0101] When the parallel arc detection unit 6 detects parallel arc discharge (YES in step S1 - 4 ), the normal operation is interrupted and the parallel stop operation is performed (step S1 - 5 ).

[0102] At this time, during the parallel stop operation, the power conversion device 3 performs a parallel arc cutting action, that is, the first switching element Q1 of the boost converter unit 10 remains in the on state or becomes and maintains the on state, and the switching elements Q2, Q4 and / or the switching elements Q3, Q5 of the inverter unit 11 remain in the off state or become and maintain the off state.

[0103] When the first time T1 has elapsed since the start of the parallel stop operation (YES in step S1 - 6 ), it is determined whether the counter m is smaller than the threshold value a (step S1 - 7 ).

[0104] At this time, the first time T1 can be appropriately changed, and is, for example, preferably 1 second or longer, and more preferably 5 seconds or longer. In addition, the first time T1 is preferably 60 seconds or shorter, and more preferably 20 seconds.

[0105] In this case, the threshold value a can be changed appropriately, and is, for example, preferably equal to or greater than 2, and more preferably equal to or greater than 3. In addition, the threshold value a is preferably equal to or less than 10, and more preferably equal to or less than 5.

[0106] When the counter m is smaller than the threshold value a ("Yes" in step S1-7), the counter m is set to m+1 (step S1-8), and the parallel stop operation is terminated (step S1-9).

[0107] It is determined whether there is a request to terminate the operation of the power supply system 1 (step S1 - 10 ). If there is a request to terminate the operation, the normal operation is terminated without restarting (“Yes” in step S1 - 10 ).

[0108] On the other hand, when the series arc detection unit 5 detects series arc discharge in step S1-3 ("Yes" in step S1-3), the process moves to step S1-11, and the normal operation is interrupted to perform series stop operation (step S1-11).

[0109] At this time, in the series stop operation, if Figure 3As shown, the power conversion device 3 compares the input voltage Vpv1 (boost circuit side voltage) from the power supply module 2 to the boost converter unit 10 and the input voltage Vc1 (inverter side voltage) from the boost converter unit 10 to the inverter unit 11 (step S2-1). When the input voltage Vpv1 is smaller than the input voltage Vc1 ("yes" in step S2-1), the first series arc cutting action is performed to keep the first switching element Q1 of the boost converter unit 10 in the disconnected state unchanged or to maintain the disconnected state (step S2-2).

[0110] On the other hand, when the input voltage Vpv1 is greater than the input voltage Vc1 ("No" in step S2-1), an arc current may flow from the boost converter unit 10 to the inverter unit 11, and therefore a second series arc cutting action is performed to keep the first switching element Q1 of the boost converter unit 10 in the disconnected state or to change it to the disconnected state, and to keep the switching elements Q2, Q3 and / or the switching elements Q4, Q5 of the inverter unit 11 in the disconnected state or to change it to the disconnected state and maintain it (step S2-3).

[0111] When the second time T2 has elapsed from the start of the tandem stop operation (YES in step S1 - 12 ), it is determined whether the counter n is smaller than the threshold value b (step S1 - 13 ).

[0112] At this time, the second time T2 can be appropriately changed, and is, for example, preferably 1 second or longer, and more preferably 5 seconds or longer. In addition, the second time T2 is preferably 60 seconds or shorter, and more preferably 20 seconds.

[0113] In this case, the threshold value b can be appropriately changed, and is, for example, preferably equal to or greater than 2, and more preferably equal to or greater than 3. In addition, the threshold value b is preferably equal to or less than 10, and more preferably equal to or less than 5.

[0114] When the counter n is smaller than the threshold value b (Yes in step S1-13), the counter n is set to n+1 (step S1-14), the series stop operation is terminated (step S1-15), and the process proceeds to step S1-10.

[0115] On the other hand, in step S1-13, when the counter n is greater than the threshold value b ("No" in step S1-13), the process moves to step S1-16, and at least the operation of the power conversion device 3 is stopped, thereby performing an operation stop operation to stop the operation of the power supply system 1.

[0116] In step S1-16, when the predetermined period T3 has elapsed since the operation of the power supply system 1 was stopped (since the operation stop operation was started) ("Yes" in step S1-17), the counter m and the counter n are reset (step S1-18), and the process moves to step S1-10.

[0117] In this case, the predetermined period T3 can be appropriately changed, and is, for example, preferably 12 hours or longer, preferably 1 day or longer. In addition, the predetermined period T3 is preferably 7 days or shorter.

[0118] In addition, the predetermined period T3 may be set to last until a predetermined time such as a set time (for example, 12 o'clock) of the next day.

[0119] In step S1-4, when the parallel arc detection unit 6 does not detect the parallel arc discharge (No in step S1-4), the process shifts to step S1-3 and the normal operation is continued.

[0120] In step S1-7, when the counter m is equal to or greater than the threshold a ("No" in step S1-7), the process proceeds to step S1-16, and an operation stop operation is performed to stop at least the operation of the power conversion device 3 and the operation of the power supply system 1 (step S1-16).

[0121] In step S1 - 10 , when there is no request to terminate the operation of the power supply system 1 (“No” in step S1 - 10 ), the process proceeds to step S1 - 2 and the normal operation is restarted.

[0122] According to the power supply system 1 of the present embodiment, when the series arc detection unit 5 detects series arc discharge and the voltage Vpv1 on the boost circuit side based on the diode unit D1 (rectifier unit) is the same as or greater than the voltage Vc1 on the inverter unit 11 side, the first switching element Q1 is turned off, and the power input from the boost converter unit 10 side to the system side connection terminals 22, 23 side is cut off by the switching elements Q2 to Q5 serving as the cut-off unit, thereby cutting off the flow of power flowing between the boost converter unit 10 and the system side connection terminals 22, 23, thereby preventing a short circuit between the positive and negative sides of the power supply module 2.

[0123] In addition, according to the power supply system 1 of the present embodiment, when the series arc detection unit 5 detects series arc discharge and the voltage Vpv1 on the boost circuit side based on the diode unit D1 is smaller than the voltage Vc1 on the inverter unit 11 side, the diode unit D1 serving as a rectifier prevents current from flowing from the boost circuit side to the inverter unit 11 side, and the flow of power flowing between the boost converter unit 10 and the system side connection terminals 22 and 23 is cut off, thereby preventing a short circuit between the positive and negative sides of the power supply module 2.

[0124] As described above, according to the power supply system 1 of the present embodiment, with the diode part D1 as a reference, no matter what the voltage Vpv1 on the boost circuit side and the voltage Vc1 on the inverter part 11 side are, there is no need to set a circuit breaker between the power supply module 2 and the power conversion device 3. Even if the overall system is not enlarged, the arc can be extinguished quickly when a series arc discharge occurs.

[0125] According to the power supply system 1 of the present embodiment, when the parallel arc detection unit 6 detects a parallel arc discharge, the first switching element Q1 is turned on to conduct (short-circuit) the positive input terminal 20a side and the negative input terminal 20b side, so that the positive input terminal 20a side and the negative input terminal 20b side have the same potential, thereby being able to quickly extinguish the parallel arc discharge. As a result, it is possible to cope with both series arc discharge and parallel arc discharge.

[0126] According to the power supply system 1 of the present embodiment, since the capacitor unit C1 is connected in parallel with the first switching element Q1 , the boost converter unit 10 can smooth the output voltage from the boost converter unit 10 to the inverter unit 11 .

[0127] According to the power supply system 1 of the present embodiment, the power conversion device 3 restarts the power conversion operation (boosting operation, voltage conversion operation) when the second time T2 has passed since the series arc detection unit 5 detected the series arc discharge. That is, even if the series arc discharge is detected, the arc discharge can be quickly extinguished, and the power conversion operation (boosting operation, voltage conversion operation) can be automatically restarted, so the operation time can be extended compared with the past.

[0128] According to the power supply system 1 of the present embodiment, when the series arc interruption operation is performed a predetermined number b or more, the operation stopping operation of the power supply system 1 is performed, so that the occurrence of fire can be prevented, and safety is high.

[0129] According to the power supply system 1 of the present embodiment, the power conversion device 3 restarts the power conversion operation (boosting operation, voltage conversion operation) when the first time T1 has passed since the parallel arc detection unit 6 detected the parallel arc discharge. That is, even if the parallel arc discharge is detected, the arc discharge can be quickly extinguished, and the power conversion operation (boosting operation, voltage conversion operation) can be automatically restarted, so the operation time can be extended compared with the past.

[0130] According to the power supply system 1 of this embodiment, when the parallel arc interruption operation is performed a predetermined number of times or more, the operation of the power supply system 1 is forcibly stopped. That is, the operation of the power conversion device 3 is forcibly stopped, so that the occurrence of fire can be prevented, and safety is high.

[0131] According to the power supply system 1 of the present embodiment, the shutdown operation is terminated when the predetermined period T3 has elapsed since the shutdown operation was performed. Therefore, the power supply system 1 can be automatically restarted.

[0132] According to the power supply system 1 of this embodiment, when the series arc detection unit 5 detects a series arc discharge, the power conversion circuit of the inverter unit 11, that is, the full-bridge circuit, is used to cut off the input power from the boost converter unit 10. Therefore, there is no need to provide a circuit breaker in the inverter unit 11, which can further suppress the increase in size.

[0133] Next, a power supply system 201 according to a second embodiment of the present invention will be described. Note that the same components as those of the power supply system 1 according to the first embodiment are denoted by the same reference numerals and description thereof will be omitted. The following description is the same.

[0134] like Figure 4 As shown, the power supply system 201 of the second embodiment includes a plurality of power supply modules 2 a and 2 b , a power conversion device 203 , a series arc detection unit 5 , a parallel arc detection unit 6 , and a control unit 7 .

[0135] (Power conversion device 203)

[0136] The power conversion device 203 includes a plurality of boost converter units 10 a and 10 b and an inverter unit 11 , and the boost converter units 10 a and 10 b are connected in parallel.

[0137] The boost converter units 10a and 10b are individually connected to the power supply modules 2a and 2b, respectively.

[0138] Next, the operation of the power supply system 201 according to the second embodiment will be described.

[0139] The operation operation of the power supply system 201 of the second embodiment is different from that of the power supply system 1 of the first embodiment in the operations during the parallel shutdown operation and the series shutdown operation.

[0140] Specifically, during the parallel stop operation of the power supply system 201, in one power supply module 2a where parallel arc discharge is detected, the first switching element Q1 of the corresponding boost converter unit 10a is kept in the on state or is turned into the on state and maintained, and the operation is continued in the remaining power supply modules 2b without change. That is, for the power generated by the remaining power supply modules 2b, the boosting operation by the boost converter unit 10b and the power conversion operation by the inverter unit 11 are continued.

[0141] In addition, during the series stop operation of the power supply system 201, in one power supply module 2a where the series arc discharge is detected, the input voltage Vpv1 from the power supply module 2a to the boost converter unit 10a is compared with the input voltage Vc1 from the boost converter unit 10a to the inverter unit 11. When the input voltage Vpv1 is lower than the input voltage Vc1, the first switching element Q1 of the boost converter unit 10a is kept in the off state or is turned into the off state and maintained, and the operation is continued in the remaining power supply modules 2b without change. That is, the boosting operation by the boost converter unit 10b and the power conversion operation by the inverter unit 11 are continued for the power generated by the remaining power supply modules 2b.

[0142] On the other hand, when the input voltage Vpv1 is greater than the input voltage Vc1, the first switching element Q1 of the boost converter unit 10a is kept in the disconnected state or is changed into the disconnected state and maintained, while the switching elements Q2 to Q5 of the inverter unit 11 are kept in the disconnected state or are changed into the disconnected state and maintained, and the operation of the remaining power supply modules 2b is stopped, and the boosting action of the remaining boost converter units 10b is also stopped.

[0143] According to the power supply system 201 of the second embodiment, the boost converter units 10a and 10b are respectively allocated to the plurality of power supply modules 2a and 2b. Furthermore, when a series arc discharge occurs in one power supply module 2a, the series arc discharge can be extinguished by only turning off the first switch element Q1 of the boost converter unit 10a when the voltage Vpv1 on the power supply module 2a side is lower than the voltage Vc1 on the inverter unit 11 side, based on the diode unit D1 of the boost converter unit 10a.

[0144] That is, the inverter unit 11 can be operated regardless of the occurrence of series arc discharge, so the operation can be continued in the remaining power supply modules 2b and the corresponding boost converter units 10b even during the series stop operation.

[0145] Next, a power supply system 301 according to a third embodiment of the present invention will be described.

[0146] like Figure 5 As shown, the power supply system 301 of this embodiment includes one or more power generation modules 302, a power conversion device 303, a bidirectional converter unit 304, a power storage module 305, a detection device 306 (arc detection unit) and a control unit 7 (arc detection unit). In addition, the power supply system 301 can connect the system power supply unit 100 to the power conversion device 303.

[0147] The power supply system 301 can supply the power generated by each power generation module 302 and the power stored in the power storage module 305 to the system power supply unit 100 connected to the power conversion device 303 .

[0148] (Power generation module 302)

[0149] The power generation module 302 is a power supply module that supplies power to the system power supply unit 100 , and is a power generation module that generates power using renewable energy such as a solar cell module or a fuel cell module.

[0150] The power generation module 302 of this embodiment uses a solar cell module, similarly to the power supply module 2 of the first embodiment.

[0151] (Power conversion device 303)

[0152] like Figure 5 As shown, the power conversion device 303 includes one or more boost converter units 10, an inverter unit 11, module-side connection terminals 20 (20a, 20b), system-side connection terminals 22, 23, and converter-side connection terminals 325 (325a, 325b).

[0153] (Boost Converter Unit 10)

[0154] Each boost converter unit 10 is electrically connected to each power generation module 302 via the module-side connection terminal 20 and the first connection wiring unit 340 (first wiring unit, wiring unit).

[0155] The module-side connection terminal 20 is composed of a positive-side input terminal 20 a and a negative-side input terminal 20 b .

[0156] The first connecting wiring portion 340 includes a first positive electrode side wiring portion 340 a and a first negative electrode side wiring portion 340 b .

[0157] The first positive electrode side wiring portion 340 a is a connection wiring that connects the positive electrode side terminal of the power generation module 302 and the positive electrode side input terminal 20 a .

[0158] The first negative electrode side wiring portion 340 b is a connection wiring that connects the negative electrode side terminal of the power generation module 302 and the negative electrode side input terminal 20 b .

[0159] (Inverter Unit 11)

[0160] The inverter unit 11 can convert DC power supplied from the power generation module 302 side and DC power supplied from the power storage module 305 side into AC power, and can convert AC power supplied from the system power supply unit 100 side into DC power.

[0161] (Bidirectional converter section 304)

[0162] The bidirectional converter unit 304 includes a step-up circuit and a step-down circuit.

[0163] That is, the bidirectional converter unit 304 is a step-down converter that steps down the power supplied from the power conversion device 303 side and supplies the stepped-down power to the power storage module 305, or a step-up converter that steps up the power supplied from the power storage module 305 and supplies the stepped-up power to the conversion device 303 side.

[0164] Here, the boost converter unit 10 is connected to the bidirectional converter unit 304 via the converter-side connection terminal 325 and the third connection wiring unit 342 (third wiring unit, wiring unit).

[0165] The converter-side connection terminal 325 is composed of a positive-side input terminal 325 a and a negative-side input terminal 325 b .

[0166] The third connecting wiring portion 342 includes a third positive electrode side wiring portion 342 a and a third negative electrode side wiring portion 342 b .

[0167] The third positive electrode side wiring portion 342 a is a connection wiring that connects the positive electrode side terminal of the bidirectional converter portion 304 and the positive electrode side input terminal 325 a .

[0168] The third negative electrode side wiring portion 342 b is a connection wiring that connects the negative electrode side terminal of the bidirectional converter portion 304 and the negative electrode side input terminal 325 b .

[0169] (Electricity Storage Module 305)

[0170] The power storage module 305 is a storage battery including one or more secondary batteries, and can be charged with the power generated by the power generation module 302 or the power supplied from the system power supply unit 100 , and can discharge the charged power to the system power supply unit 100 .

[0171] like Figure 5 As shown, the power storage module 305 is electrically connected to the bidirectional converter unit 304 via a second connection wiring unit 341 (second wiring unit, wiring unit).

[0172] The second connecting wiring portion 341 includes a second positive electrode side wiring portion 341 a and a second negative electrode side wiring portion 341 b .

[0173] The second positive electrode side wiring portion 341 a is a connection wiring that connects the positive electrode side terminal of the power storage module 305 and the positive electrode side terminal of the bidirectional converter unit 304 .

[0174] The second negative electrode side wiring portion 341 b is a connection wiring that connects the negative electrode side terminal of the power storage module 305 and the negative electrode side terminal of the bidirectional converter unit 304 .

[0175] (Detection device 306)

[0176] The detection device 306 is a coil-type sensor (loop coil sensor) having a detection coil, and is a device capable of measuring (detecting) high-frequency noise generated by arc discharge in the target wiring without contacting the wiring.

[0177] For the power supply system 301 of this embodiment, if Figure 5 As shown, the first connecting wiring part 340, the second connecting wiring part 341 and the third connecting wiring part 342 are respectively wirings that become the objects of the detection device 306 (wirings that become the measurement objects), and separate detection devices 306 are arranged near each wiring part 340~342 and at positions not in contact with each wiring part 340~342.

[0178] That is, the power supply system 301 is provided with the detection device 306 corresponding to the first connection wiring section 340 , the second connection wiring section 341 , and the third connection wiring section 342 .

[0179] In the power supply system 301 of this embodiment, Figure 5 , Figure 6 As shown, a cutting device 350 is provided in the middle of each of the first connection wiring portion 340 , the second connection wiring portion 341 , and the third connection wiring portion 342 .

[0180] In the following description, the cutting device 350 provided in the middle of the first connection wiring part 340 is described in detail, and the cutting device 350 provided in the middle of the second connection wiring part 341 and the third connection wiring part 342 is the same, so the detailed description is omitted.

[0181] like Figure 6 As shown, the disconnecting device 350 includes a positive wiring portion 351 , a negative wiring portion 352 , a short-circuiting wiring portion 353 , a first relay portion 354 (serial arc disconnecting portion), and a second relay portion 355 (parallel arc short-circuiting portion).

[0182] The positive electrode wiring portion 351 is located in the middle of the first positive electrode side wiring portion 340 a .

[0183] Specifically, the positive electrode wiring portion 351 is located between a portion of the first positive electrode wiring portion 340a on the power generation module 302 side and a portion of the first positive electrode wiring portion 340a on the boost converter unit 10 (power conversion device 303) side, and electrically connects them.

[0184] That is, the positive electrode wiring portion 351 constitutes a part of the first positive electrode side wiring portion 340 a , and specifically, forms a midway portion of the first positive electrode side wiring portion 340 a .

[0185] The negative electrode wiring portion 352 is located in the middle of the first negative electrode side wiring portion 340 b .

[0186] Specifically, the negative electrode wiring portion 352 is located between a portion of the first negative electrode wiring portion 340b on the power generation module 302 side and a portion of the first negative electrode wiring portion 340b on the boost converter unit 10 (power conversion device 303) side, and electrically connects them.

[0187] That is, the negative electrode wiring portion 352 constitutes a part of the first negative electrode side wiring portion 340b, and forms a midway portion of the first negative electrode side wiring portion 340b.

[0188] The short-circuit wiring portion 353 is a connection wiring that connects the positive electrode wiring portion 351 and the negative electrode wiring portion 352 , and is a portion that allows electrical conduction between the positive electrode wiring portion 351 and the negative electrode wiring portion 352 .

[0189] The first relay unit 354 is a relay that is provided in the middle of the positive wiring unit 351 and automatically switches on and off. It is a part that switches the conduction state and the cutoff state of the power between the power generation module 302 side and the boost converter unit 10 (power conversion device 303) side by turning on and off.

[0190] The first relay unit 354 is in a closed state in a normal state where arc discharge is not generated, and the power generation module 302 side and the boost converter unit 10 side are in a conductive state.

[0191] The second relay unit 355 is a relay that is provided in the middle of the short-circuit wiring unit 353 and automatically switches on and off. It is a part that switches the conduction state and the cutoff state of the power between the positive wiring unit 351 side and the negative wiring unit 352 side by turning on and off.

[0192] The second relay portion 355 is in an open state in a normal state where arc discharge is not generated, and the positive electrode wiring portion 351 side and the negative electrode wiring portion 352 side are in an open state (disconnected state).

[0193] Next, the risk level determination operation executed by the power supply system 301 according to the present embodiment will be described in detail.

[0194] The risk level determination operation is an operation of determining whether arc discharge has occurred in a predetermined wiring and, if it is determined that arc discharge has occurred, determining whether the generated arc discharge is a serious arc discharge (large-scale arc discharge) that may cause a fire or the like.

[0195] In the hazard level determination action of the present embodiment, the first connection wiring section 340, the second connection wiring section 341 and the third connection wiring section 342 are taken as target wiring (wiring sections), and it is determined whether arc discharge has occurred in these wirings and whether the generated arc discharge is a serious arc discharge that may cause fire, etc.

[0196] In the following description, the risk level determination operation for the first connection wiring section 340 will be described in detail.

[0197] First, before the risk assessment action, set Figure 7 The time setting value T10 (first threshold), the voltage setting value V1, the current setting value I1 and the work amount reference value J1 (second threshold) are shown.

[0198] The time setting value T10 is a value set based on data of accidents caused by arc discharge that occurred in other solar power generation systems in the past or based on the experience of the manager.

[0199] The time setting value T10 is preferably a value greater than 0 seconds and less than 2.5 seconds, and more preferably a value greater than or equal to 1.5 seconds.

[0200] The time setting value T10 in this embodiment is 2.4 seconds.

[0201] The voltage setting value V1 is a value set based on data of accidents caused by arc discharge in other solar power generation systems in the past and on the experience of the manager. In other words, the voltage setting value V1 is the magnitude of the discharge potential predicted when an arc discharge occurs.

[0202] The voltage setting value V1 is preferably a value of 0 V or more and less than 50 V, and more preferably a value of 30 V or more.

[0203] The voltage setting value V1 in this embodiment is 40V.

[0204] The current setting value I1 is a value set according to the output current value of the power generation module 302 connected to the first connection wiring section 340 . In this embodiment, the value of the maximum output operating current (Ipm) of the power generation module 302 is set as the current setting value I1 .

[0205] That is, the current setting value I1 is a value that increases or decreases according to the output current value of the power generation module 302 used in the power supply system 301 .

[0206] Therefore, when the output current value (maximum output operating current value) of the power generation module 302 used is small, the current setting value I1 also becomes small, and when the output current value of the power generation module 302 used is large, the current setting value I1 also becomes large.

[0207] In addition, in this embodiment, the current setting value I1 is set to a value substantially the same as the maximum output operating current of the power generation module 302, but the "substantially the same value" mentioned here is not limited to completely identical values, and an error of a few percent is allowed. For example, as long as the difference between the two is within 5%, it is allowed.

[0208] In addition, the current setting value I1 may be set to a value substantially equal to the maximum output operating current of the power generation module 302 or to a short-circuit current value (Isc) of the power generation module 302 .

[0209] The work amount reference value J1 is a value set based on data of accidents caused by arc discharge that occurred in other solar power generation systems in the past and on the experience of the manager, and is a threshold value that serves as a reference for the magnitude of arc discharge.

[0210] The work amount reference value J1 is preferably a value exceeding 0 J (Joule) and not more than 850 J (Joule), and more preferably a value of 500 J or more and 750 J or less.

[0211] The work amount reference value J1 of the present embodiment is 750J.

[0212] The time setting value T10, voltage setting value V1, current setting value I1 and work amount reference value J1 can be set by the operator inputting values ​​using information input means such as a keyboard, or can be set by the operator selecting a value from candidate values ​​(candidate values) displayed in a list.

[0213] In this way, in addition to setting by an operator's input operation, it is also possible to automatically set based on information received from an external computer.

[0214] That is, a signal (information indicating a value) may be received from an external server, and setting may be automatically performed based on the received signal (information indicating a value).

[0215] In the power supply system 301 of the present embodiment, when the operation starts, the detection device 306 performs a detection (measurement) operation.

[0216] Specifically, the detection device 306 always monitors whether high-frequency noise (hereinafter also referred to as high-frequency noise) accompanying the generation of arc discharge is generated in the first connection wiring portion 340. If the detection device 306 detects the generation of high-frequency noise, it obtains the generation time (duration) of the high-frequency noise.

[0217] That is, the detection device 306 updates the generation time (duration time) every predetermined time from the reference time when the generation of high-frequency noise is detected. In other words, the detection device 306 detects the presence of high-frequency noise at predetermined intervals from the time when the high-frequency noise is first detected, and updates the generation time as the duration time every time the high-frequency noise is detected.

[0218] For example, if it is detected that 0.5 seconds have passed since the high-frequency noise was generated, the generation time (duration time) becomes 0.5 seconds, and if 1 second has passed, the generation time (duration time) becomes 1 second.

[0219] In the power supply system 301 of this embodiment, when the generation of high-frequency noise is detected, it is determined that arc discharge has occurred. Then, the generation time (duration) of the high-frequency noise is obtained as the generation time TA (duration TA) of the arc discharge. That is, the detection device 306 and the control unit 7 function as an arc detection unit.

[0220] In the power supply system 301 of this embodiment, Figure 7 As described above, when the detection device 306 does not detect the generation of high-frequency noise (“No” in step S3 - 1 ), it is continuously determined whether the high-frequency noise is generated.

[0221] Moreover, if the generation of high-frequency noise is detected by the detection device 306 (the case of "yes" in step S3-1), the duration of the high-frequency noise from the time of generation of the high-frequency noise, that is, the generation time of the high-frequency noise, is obtained as the generation time TA of the arc discharge (duration time TA), and the generation time TA of the arc discharge is compared with the time setting value T10 (step S3-2).

[0222] Then, when the arc discharge generation time TA (continuation time TA) exceeds the time setting value T10 (if YES in step S3-2, if the first reference is reached), it is determined that a highly dangerous arc discharge has occurred (step S3-3).

[0223] In contrast, when the arc discharge generation time TA (duration time TA) is less than the time setting value T10 (the case of "No" in step S3-2), the generated discharge work JA (risk judgment work) is calculated by the following formula (1), and the generated discharge work JA is compared with the work reference value J1 (step S3-4).

[0224] JA=I1*V1*TA…(1)

[0225] Then, when the generated discharge work amount JA exceeds the work amount reference value J1 (if YES in step S3-4, if the second reference value is reached), the process proceeds to step S3-3, and it is determined that a highly dangerous arc discharge has occurred.

[0226] In contrast, when the generated discharge work JA is less than the work reference value J1 ("No" in step S3-4), it is confirmed whether the arc discharge continues (step S3-5). When high-frequency noise is detected and the arc discharge does not continue ("No" in step S3-5), it is determined that the generated arc discharge is of low risk.

[0227] That is, in the present embodiment, when the arc discharge generation time TA is equal to or less than the time setting value T10 and the generated discharge work amount JA is equal to or less than the work amount reference value J1, it is determined that the danger of the generated arc discharge is low.

[0228] On the other hand, in step S3-5, when high-frequency noise is detected and arc discharge continues ("Yes" in step S3-5), the generation time TA (continuation time TA) is updated, and the process shifts to step S3-2.

[0229] As described above, the power supply system 301 of this embodiment includes the cutoff device 350 (see Figure 6 ), when it is determined that a dangerous arc discharge has occurred (step S3-3), an arc cutting operation is performed. The arc discharge cutting operation is an operation to extinguish the generated dangerous arc discharge.

[0230] In the arc cutting action, first, Figure 8 As shown, the first relay unit 354 is opened to cut off the conduction of electric power between the power generation module 302 side and the boost converter unit 10 side (step S4-1).

[0231] In addition, before and after this, the detection device 306 detects whether high-frequency noise is generated.

[0232] Specifically, after the first relay unit 354 is opened, if the detection device 306 continues to detect no high-frequency noise (arc discharge) (No in step S4-2), it is determined that the generated arc discharge is a series arc discharge and the arc discharge has been extinguished (step S4-3).

[0233] On the other hand, even if the first relay unit 354 is opened in step S4-1, if high-frequency noise (arc discharge) continues to be detected by the detection device 306 ("yes" in step S4-2), it is determined that the generated arc discharge is a parallel arc discharge and the arc discharge has not yet been extinguished (step S4-4).

[0234] When it is determined in step S4-4 that the generated arc discharge is a parallel arc discharge (when high-frequency noise is continuously detected), the first relay unit 354 is switched from the open state to the closed state, and the second relay unit 355 is switched to the closed state (step S4-5).

[0235] That is, the first relay unit 354 is closed to enable power conduction between the power generation module 302 and the boost converter unit 10, and the second relay unit 355 is closed to short-circuit the positive wiring unit 351 and the negative wiring unit 352. Thus, the arc discharge is extinguished.

[0236] The risk level determination operation and the disconnection operation for the second connection wiring section 341 and the third connection wiring section 342 are substantially the same as those for the first connection wiring section 340 , and thus detailed descriptions thereof are omitted.

[0237] In addition, when the second connection wiring section 341 is used as the target, the current setting value I1 is a value set according to the output current value of the power storage module 305. In addition, when the third connection wiring section 342 is used as the target, the current setting value I1 is a value set based on data of accidents caused by arc discharge that occurred in other solar power generation systems in the past, etc., and based on the experience of the manager.

[0238] According to the power supply system 301 of the third embodiment, each detection device 306 can obtain the presence or absence of arc discharge and the generation time of arc discharge (duration of arc discharge) in the first connection wiring part 340, the second connection wiring part 341 and the third connection wiring part 342 as the target without contacting the first connection wiring part 340, the second connection wiring part 341 and the third connection wiring part 342 as the target, thereby facilitating the addition of the arc detection unit.

[0239] According to the power supply system 301 of the third embodiment, it is possible to determine whether the generated arc discharge is a highly dangerous (large-scale) arc discharge that may cause a fire, using a simple configuration, and thus it is possible to take appropriate measures against the generated arc discharge.

[0240] According to the power supply system 301 of the third embodiment, when the result of comparing the arc discharge generation time TA (duration TA) with the time setting value T10 is that the generated arc discharge generation time TA (duration TA) is less than the time setting value T10 (when it is not judged as reaching the first reference), the generated discharge work JA (risk judgment work) is compared with a preset work reference value J1, and based on the result of the comparison, it is judged whether the generated arc discharge reaches the reference related to the dangerousness, that is, the second reference. Therefore, the dangerousness of the generated arc discharge can be judged more accurately.

[0241] According to the power supply system 301 of the third embodiment, when the generation time TA (duration TA) of the generated arc discharge exceeds the time setting value T10 or when the generated discharge work JA exceeds the work reference value J1, the arc cutting action is performed. Moreover, in the arc cutting action, when the conduction of power between the power generation module 302 and the power conversion device 303 is cut off by the first relay unit 354 and the arc continues to be generated after the cut-off, the cut-off based on the first relay unit 354 is released, and the positive wiring unit 351 and the negative wiring unit 352 are connected by the second relay unit 355. Therefore, regardless of whether the generated arc discharge is a series arc or a parallel arc, the arc can be properly extinguished by the arc cutting action.

[0242] According to the power supply system 301 of the third embodiment, the current setting value I1, the voltage setting value V1, and the work amount reference value J1 are set based on information input by an information input unit that accepts information input from a user or information sent from an external device. Therefore, appropriate settings can be made for various power supply systems, respectively, and the danger of arc discharge can be accurately determined in various power supply systems.

[0243] In the first and second embodiments described above, in the series stop operation, the first series arc cutoff operation and the second series arc cutoff operation are determined based on the difference between the voltage Vp1 on the power supply module 2 side and the voltage on the inverter 11 side, with the diode unit D1 as a reference, but the present invention is not limited thereto. The first series arc cutoff operation and the second series arc cutoff operation may be performed sequentially.

[0244] Specifically, in the series stop operation, if Fig. 9 As shown, a first series arc cutting operation is performed to keep the first switching element Q1 of the boost converter unit 10 in an off state or to maintain the off state (step S5-1), and it is determined whether the current value Ipv of the power supply module 2 is 0 (step S5-2).

[0245] When the current value Ipv of the power supply module 2 is not 0 ("No" in step S5-2), a second series arc cutting action is implemented to keep the first switching element Q1 of the boost converter unit 10 in the off state and keep the switching elements Q2~Q5 of the inverter unit 11 in the off state unchanged or in the off state and maintain it (step S5-3).

[0246] On the other hand, when the current value Ipv of the power supply module 2 is 0 (YES in step S5 - 2 ), the first series arc interruption operation is continued as it is.

[0247] In the first and second embodiments, the parallel shutdown operation is terminated when the first time T1 has passed since the start of the parallel shutdown operation, but the present invention is not limited thereto. The parallel shutdown operation may be terminated when the parallel arc detector 6 does not detect a parallel arc discharge.

[0248] In the first and second embodiments, the series stop operation is terminated when the second time T2 has elapsed since the start of the series stop operation, but the present invention is not limited thereto. The series stop operation may be terminated when the series arc detector 5 does not detect a series arc discharge.

[0249] In the second embodiment described above, both power supply modules 2a and 2b are solar cell modules, but the present invention is not limited thereto. The power supply modules 2a and 2b may also be different types of power supply modules. For example, the power supply module 2a may be a solar cell module, and the power supply module 2b may be a fuel cell module.

[0250] Similarly, in the third embodiment described above, the power generation modules 302 are all solar cell modules, but the present invention is not limited thereto. The power generation modules 302 may also be different types of power generation modules.

[0251] In the second embodiment described above, the power supply system 201 is described as having two power supply modules 2a and 2b, but the present invention is not limited thereto. The power supply system 201 may also have three or more power supply modules 2. In this case, it is preferred that a boost converter unit 10 is provided corresponding to each power supply module 2.

[0252] Similarly, in the third embodiment described above, the power supply system 301 is described as having two power generation modules 302 , but the present invention is not limited thereto. The power supply system 301 may have one power generation module 302 or may have three or more power generation modules 302 .

[0253] In the first and second embodiments described above, in the first series arc cutoff operation, the diode unit D1 cuts off the input of power to the inverter unit 11, and thus the switching elements Q2 to Q5 of the inverter unit 11 are not controlled, but the present invention is not limited thereto. As in the second series arc cutoff operation, the switching elements Q2 to Q5 of the inverter unit 11 may be kept in the disconnected state or in the disconnected state and maintained.

[0254] In the first embodiment and the second embodiment described above, when the parallel arc cutting action and the second series arc cutting action are implemented, although each switch element Q2 to Q5 is set to the disconnected state, the present invention is not limited to this. As long as the flow of power flowing between the boost converter unit 10 and the system-side connection terminals 22 and 23 can be cut off, the combination of the second switch element Q2 and the third switch element Q3 connected to the positive side of the power supply module 2, and / or the combination of the fourth switch element Q4 and the fifth switch element Q5 connected to the negative side of the power supply module 2 can be set to the disconnected state to cut off the flow of power flowing between the boost converter unit 10 and the system-side connection terminals 22 and 23 (connection terminals).

[0255] In addition, a relay circuit may be provided between each arm of the full-bridge circuit having the switching elements Q2 to Q5 and the system-side connection terminals 22 and 23 to cut off the flow of power flowing between the boost converter unit 10 and the system-side connection terminals 22 and 23 (connection terminals).

[0256] In the above-mentioned first embodiment and second embodiment, when the parallel arc detection unit 6 detects a parallel arc discharge, a parallel arc cutting action is performed, the first switching element Q1 is turned on and the positive side input terminal 20a side and the negative side input terminal 20b side are connected via the first switching element Q1 to extinguish the parallel arc discharge, but the present invention is not limited to this.

[0257] For example, a relay circuit may be provided between each arm of the full bridge circuit having the switching elements Q2 to Q5 and the system side connection terminals 22 and 23. When the parallel arc detection unit 6 detects a parallel arc discharge, the relay circuit cuts off the flow of power flowing between the boost converter unit 10 side and the system side connection terminals 22 and 23 (connection terminals), and turns on the combination of the second switching element Q2 and the fourth switching element Q4 and / or the combination of the third switching element Q3 and the fifth switching element Q5, and conducts the positive side input terminal 20a and the negative side input terminal 20b via the switching elements Q2 and Q4 and / or the switching elements Q3 and Q5 in the turned-on state, thereby extinguishing the parallel arc discharge. In this case, the first switching element Q1 may be in the turned-on state or the turned-off state.

[0258] In the above embodiment, the inverter unit 11 converts DC power into AC power using a full-bridge circuit, but the present invention is not limited thereto. The inverter unit 11 may convert DC power into AC power using a half-bridge circuit.

[0259] In the above embodiment, the switching elements Q1 to Q5 are PWM controlled by one control unit 7 , but the present invention is not limited thereto, and a plurality of control units 7 may PWM control the switching elements Q1 to Q5 individually or in groups.

[0260] In the above-mentioned embodiment, the series arc detection unit 5 and the parallel arc detection unit 6 are separate bodies, but the present invention is not limited thereto. The series arc detection unit 5 and the parallel arc detection unit 6 may be integrated.

[0261] In the above embodiment, the converter unit 10 is a boost converter having a boost circuit as a converter circuit and boosting a voltage, but the present invention is not limited thereto and the converter unit 10 may be a buck converter having a buck circuit as a converter circuit and bucking a voltage.

[0262] In the above-mentioned embodiment, an example in which the cutoff device 350 is provided is described, but it is not necessary to provide the cutoff device 350. For example, when it is determined that a dangerous arc discharge has occurred, a signal indicating this fact may be sent to an external computer, terminal, etc. used by an operator, and a reporting operation of reporting this fact may be performed by these devices.

[0263] The cutoff device 350 does not necessarily need to be provided outside the power conversion device 303, and it is also conceivable to modify the power conversion device 303 and provide it inside the power conversion device 303. However, it is preferably provided outside the power conversion device 303 from the viewpoint of facilitating retrofitting.

[0264] The power supply system 301 of the above-mentioned embodiment has the bidirectional converter unit 304 and the power storage module 305, but they are not essential and may be a structure without them. In this case, the second connection wiring unit 341 and the third connection wiring unit 342 may not be provided, and the first connection wiring unit 340 may be used as the wiring unit to be the object.

[0265] The detection device 306 and the cutoff device 350 can be easily added, and the power supply system 301 of the third embodiment described above can be easily constructed based on the existing power supply system.

[0266] Here, the existing power supply systems installed in various places each use various power generation modules with different outputs. The risk determination action of the above-mentioned embodiment can be performed in various power supply systems by only appropriately changing the current setting value I1 according to the output of the power generation module 302. That is, it is easy to install later compared to each power supply system constructed based on various existing power supply systems. In other words, the risk determination action of the above-mentioned embodiment has high versatility in later installation.

[0267] In the third embodiment described above, the arc discharge is cut off by performing the arc cutting action using the cutting device 350, but the present invention is not limited thereto. The arc discharge may also be cut off using the power conversion device 303 as in the first embodiment. For example, after performing the first series arc cutting action or the second series arc cutting action of the first embodiment, it may be confirmed whether the high-frequency noise is still detected, and if it is still detected, the parallel arc cutting action may be performed.

[0268] Regarding the above-mentioned embodiments, each component can be freely replaced or added between the embodiments as long as it is included in the technical scope of the present invention.

[0269] Description of Reference Numerals

[0270] 1, 201, 301…power supply system; 2…power supply module; 3, 203, 303…power conversion device; 5…series arc detection unit; 6…parallel arc detection unit; 7…control unit (arc detection unit); 10…boost converter unit (converter unit); 11…inverter unit; 22, 23…system side connection terminal; 100…system power supply unit; 302…power generation module; 304…bidirectional converter unit; 305…power storage module; 306…detection device (arc detection unit); 340…first series Connection wiring section (first wiring section, wiring section); 341…second connection wiring section (second wiring section, wiring section); 342…third connection wiring section (third wiring section, wiring section); 351…positive wiring section; 352…negative wiring section; 354…first relay section (series arc cut-off section); 355…second relay section (parallel arc short-circuit section); C1…capacitor section; D1…diode section (rectifier section); L1, L2…reactor section; Q1…switching element; Q2~Q5…switching element (cut-off section).

Claims

1. A power supply system, characterized in that: It has a power supply module, a power conversion device and a series arc detection unit. The power conversion device includes a converter unit, an inverter unit, and a connection terminal that can be electrically connected to a system power supply unit. The converter unit includes a converter circuit in which a reactor unit and a first switching element are connected in series, and is capable of performing a voltage transformation operation, wherein the voltage transformation operation steps up or steps down an input voltage from the power supply module by switching an on state and an off state of the first switching element, and outputs power to the inverter unit. The converter unit includes a rectifier unit that allows a current to flow from the converter circuit side to the inverter unit side and blocks a current from flowing from the inverter unit side to the converter circuit side. The inverter unit includes a cutoff unit capable of cutting off power supply from the inverter unit to the connection terminal side. The series arc detection unit is capable of detecting series arc discharge at a portion closer to the power supply module than the power conversion device. When the series arc detection unit detects a series arc discharge, a series arc cutting-off action is performed, which stops the transformation action and causes the first switching element to maintain the disconnected state or to become and maintain the disconnected state, and cuts off the flow of power flowing between the converter unit and the connection terminal through the cutting unit or the rectifying unit.

2. The power supply system according to claim 1, characterized in that: The converter unit is a step-up converter unit, and the converter circuit is a step-up circuit. The boost converter unit is capable of performing a boost operation that boosts an input voltage from the power supply module by switching an on state and an off state of the first switching element, and outputs power to the inverter unit. When the series arc detection unit detects series arc discharge, the series arc cutoff action stops the boost action, and causes the first switching element to maintain the disconnected state or to become and maintain the disconnected state, and the flow of power flowing between the boost converter unit and the connection terminal is cut off by the cutoff unit or the rectifier unit.

3. The power supply system according to claim 2, characterized in that: have: a parallel arc detection unit for detecting a parallel arc discharge at a portion closer to the power supply module than the power conversion device; When the parallel arc detection unit detects a parallel arc discharge, a parallel arc cutoff operation is performed to stop the voltage step-up operation and keep the first switching element in the on state or maintain the on state.

4. The power supply system according to claim 2 or 3, characterized in that: When a predetermined time has elapsed since the series arc detection unit detected the series arc discharge, the voltage step-up operation is restarted.

5. The power supply system according to claim 4, characterized in that: When the series arc interruption operation is performed a predetermined number of times or more, an operation stopping operation of stopping the operation of the power conversion device is performed.

6. The power supply system according to claim 3, characterized in that: When a predetermined time has elapsed since the parallel arc detection unit detected the parallel arc discharge, the voltage step-up operation is restarted.

7. The power supply system according to claim 6, characterized in that: When the parallel arc interruption operation is performed a predetermined number of times or more, an operation stopping operation of stopping the operation of the power conversion device is performed.

8. The power supply system according to claim 5 or 7, characterized in that: When a predetermined period of time has elapsed since the execution of the operation stop operation, the operation stop operation is terminated.

9. The power supply system according to any one of claims 2 to 8, characterized in that: The inverter unit includes a second switching element, a third switching element, a fourth switching element, and a fifth switching element. The inverter unit includes a full-bridge circuit in which the second switching element and the fifth switching element, and the third switching element and the fourth switching element are respectively arranged at diagonals. When the series arc detection unit detects series arc discharge, the flow of power flowing between the boost converter unit and the connection terminal is cut off by turning off at least one of the combination of the second switching element and the third switching element and the combination of the fourth switching element and the fifth switching element.

10. The power supply system according to claim 2, characterized in that: With multiple power supply modules, The power conversion device includes a plurality of boost converter units. The plurality of boost converters are electrically connected to the plurality of power supply modules respectively. The series arc detection unit can detect series arc discharges at the portion closer to each power supply module than the power conversion device. When the series arc detection unit detects series arc discharge on the part on the side of one power supply module, and in the boost converter unit corresponding to the one power supply module, the voltage on the boost circuit side is smaller than the voltage on the inverter unit side based on the rectifier unit, in the boost converter unit corresponding to the one power supply module, the boost action is stopped, and the first switching element is kept in the disconnected state or is changed to the disconnected state and maintained, and the boost action is continued in the boost converter units corresponding to the other power supply modules.

11. The power supply system according to any one of claims 1 to 10, characterized in that: A power supply module, a power conversion device, a first wiring portion electrically connecting the power supply module and the power conversion device, and an arc detection unit. The arc detection unit can detect arc discharge of the first wiring portion without contacting the first wiring portion. When the arc detection unit detects an arc discharge, a hazard level determination action is performed, which compares the duration of the arc discharge from the time the arc discharge is detected with a first threshold value, and determines whether the generated arc discharge reaches a first benchmark related to hazard based on the result of the comparison with the first threshold value.

12. The power supply system according to claim 11, characterized in that When the result of comparing the duration with the first threshold value is that the generated arc discharge is not determined to have reached the first reference, the hazard level determination operation compares the risk determination work with a preset second threshold value, and determines whether the generated arc discharge has reached a second reference related to the hazard level based on the result of the comparison with the second threshold value. The risk determination work amount is calculated based on a current setting value corresponding to an output of the power supply module, a voltage setting value based on a voltage when arc discharge occurs, and the duration.

13. The power supply system according to claim 12, characterized in that: The current setting value, the voltage setting value, and the second threshold value are set based on information input by an information input unit that receives information input from a user or information transmitted from an external device.

14. A power supply system, characterized in that: A power supply module, a power conversion device, a first wiring portion electrically connecting the power supply module and the power conversion device, and an arc detection unit. The arc detection unit can detect arc discharge of the first wiring portion without contacting the first wiring portion. When the arc detection unit detects an arc discharge, a hazard level determination action is performed, which compares the duration of the arc discharge from the time the arc discharge is detected with a first threshold value, and determines whether the generated arc discharge reaches a first benchmark related to hazard based on the result of the comparison with the first threshold value.

15. A power supply system, characterized in that: It has a power generation module, a power conversion device, a power storage module, a bidirectional converter unit and an arc detection unit. and having a first wiring portion electrically connecting the power generation module and the power conversion device, a second wiring portion electrically connecting the power storage module and the bidirectional converter portion, and a third wiring portion electrically connecting the bidirectional converter portion and the power conversion device, The arc detection unit can detect arc discharge of the one wiring portion without contacting at least one wiring portion selected from the first wiring portion, the second wiring portion, and the third wiring portion. When the arc detection unit detects an arc discharge in one of the wiring sections, a hazard level determination action is performed, which compares the duration from the detection of the arc discharge in the one of the wiring sections to the extinction of the arc discharge with a first threshold value, and determines whether the generated arc discharge reaches a first benchmark related to hazard based on the result of the comparison with the first threshold value.

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