WO2020065857A1 - Power conversion device - Google Patents

Power conversion device Download PDF

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Publication number
WO2020065857A1
WO2020065857A1 PCT/JP2018/036059 JP2018036059W WO2020065857A1 WO 2020065857 A1 WO2020065857 A1 WO 2020065857A1 JP 2018036059 W JP2018036059 W JP 2018036059W WO 2020065857 A1 WO2020065857 A1 WO 2020065857A1
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WO
WIPO (PCT)
Prior art keywords
current
short
circuit
input unit
unit
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Application number
PCT/JP2018/036059
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French (fr)
Japanese (ja)
Inventor
朋也 勝倉
Original Assignee
東芝三菱電機産業システム株式会社
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Application filed by 東芝三菱電機産業システム株式会社 filed Critical 東芝三菱電機産業システム株式会社
Priority to JP2019525030A priority Critical patent/JP6733818B1/en
Priority to PCT/JP2018/036059 priority patent/WO2020065857A1/en
Publication of WO2020065857A1 publication Critical patent/WO2020065857A1/en

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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/66—Regulating electric power
    • G05F1/67—Regulating electric power to the maximum power available from a generator, e.g. from solar cell
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode

Definitions

  • FIG. 9 of the above publication describes a configuration in which a plurality of solar cell strings are provided, and an ammeter is provided for each of the solar cell strings.
  • a short circuit occurs between the positive electrode and the negative electrode in a power system
  • a large current flows through the short circuit.
  • This large current is generally cut off by a protection element such as a fuse.
  • the present invention has been made to solve the above-described problems, and has as its object to provide a power converter having a function of detecting a short circuit between a positive electrode and a negative electrode.
  • the first power converter is: A first DC input unit constructed to accept the first DC current, A power conversion circuit that outputs an AC current by converting the first DC current input from the first DC input unit, A first current detector provided in the first DC input unit, It was detected based on the output of the first current detector that the magnitude of the first reverse current flowing in the opposite direction to the first DC current through the first DC input section exceeded a first determination value.
  • a short-circuit detection unit configured to output a first short-circuit detection signal, Is provided.
  • the second power converter is: A first DC input unit constructed to accept the first DC current, A second DC input unit configured to accept a second DC current, A positive input terminal connected to each positive electrode of the first DC input unit and the second DC input unit, and a negative electrode connected to each negative electrode of the first DC input unit and the second DC input unit A power conversion circuit having an input end; A first current detector provided in the first DC input unit, A second current detector provided in the second DC input unit, If the total current value obtained by summing the current value detected by the first current detector and the current value detected by the second current detector exceeds the determination value, a short-circuit detection signal is output. Short-circuit detection unit, Is provided.
  • the short-circuit detection unit can detect whether the first DC current is correctly flowing in the forward direction. . If the first reverse current flowing in the reverse direction is generated, and the magnitude of the first reverse current exceeds the reference level, the reverse current having a magnitude exceeding the normal range is usually assumed. Flows toward the first solar cell strings. In this case, there is a high possibility that a short circuit between the first positive electrode and the negative electrode, which is a short circuit on the first solar cell string side, has occurred. Therefore, the short-circuit detection unit can output a short-circuit detection signal indicating that such a short circuit between the first positive electrode and the negative electrode has occurred.
  • the short-circuit detector can make the determination. If the magnitude of the total current exceeds the reference level, a current having a magnitude exceeding the normal range usually flows toward the power conversion circuit. In this case, there is a high possibility that a short circuit between the second positive electrode and the negative electrode, in which the positive electrode and the negative electrode of the power conversion circuit are short-circuited, has occurred. Thus, the short-circuit detection unit can output a short-circuit detection signal indicating that such a short circuit between the second positive electrode and the negative electrode has occurred.
  • FIG. 2 is a circuit diagram showing a configuration of a power converter according to the embodiment and a first short-circuit mode.
  • FIG. 3 is a block diagram illustrating a first short-circuit detection unit according to the embodiment.
  • FIG. 3 is a circuit diagram illustrating a configuration of a power conversion device according to the embodiment and a second short-circuit mode.
  • FIG. 4 is a block diagram illustrating a second short-circuit detection unit according to the embodiment.
  • FIG. 6 is a diagram for explaining an operation of the second short-circuit detection unit according to the embodiment.
  • FIG. 10 is a block diagram illustrating a second short-circuit detection unit according to a modification of the embodiment. 4 is a configuration example of a control unit according to the embodiment.
  • the “first short-circuit mode” is a mode in which the first positive-negative-electrode short-circuit X1 shown in FIG. 1 has occurred.
  • the “second short-circuit mode” is a mode in which the second short-circuit between the positive electrode and the negative electrode X2 illustrated in FIG. 3 has occurred.
  • FIG. 1 is a circuit diagram showing a configuration of a power conversion device 6 according to the embodiment and a first short-circuit mode.
  • FIG. 1 also shows a photovoltaic power generation system 1 including a power converter 6.
  • the solar power generation system 1 includes a first solar cell string # 1, a second solar cell string # 2, a third solar cell string # 3, a first connection box 4a, a second connection box 4b, and a third It includes a connection box 4c, a power conversion device 6, and a transformer 16.
  • the first solar cell string # 1 includes a plurality of solar cell panels 2a.
  • the first direct current output from each of the plurality of solar cell panels 2a joins inside the first connection box 4a.
  • the second solar cell string # 2 includes a plurality of solar cell panels 2b.
  • the second direct current output from each of the plurality of solar cell panels 2b joins inside the second connection box 4b.
  • first solar cell string # 1 the second solar cell string # 2
  • third solar cell string # 3 may be collectively referred to as "solar cell strings # 1 to # 3".
  • the solar power generation system 1 converts the DC power generated by the solar cell strings # 1 to # 3 into AC power by the power converter 6.
  • the photovoltaic power generation system 1 is connected to the power system 17 in a system interconnection operation.
  • the AC power converted by the power converter 6 is supplied to the power system 17.
  • the power conversion device 6 includes a first DC input unit 91, a second DC input unit 92, a third DC input unit 93, a first current detector 10a, and a second current detection unit. , A third current detector 10c, a DC side circuit breaker 11, a power conversion circuit 12, a DC smoothing capacitor 13, a switch SW, an AC filter circuit 14, an AC side circuit breaker 15, and a control unit. 20.
  • the first DC input unit 91, the second DC input unit 92, and the third DC input unit 93 each include a positive terminal 9a and a negative terminal 9b.
  • the fuse 7 is provided inside each of the first DC input unit 91, the second DC input unit 92, and the third DC input unit 93.
  • a fuse 7 is also provided inside the first connection box 4a, the second connection box 4b, and the third connection box 4c.
  • the positive terminal 9a of the first DC input unit 91 is connected to the positive terminal of the first connection box 4a, and the negative terminal 9b of the first DC input unit 91 is connected to the negative terminal of the first connection box 4a.
  • the first DC input unit 91 is configured to receive the first DC current supplied from the first solar cell string # 1.
  • the positive terminal 9a of the second DC input unit 92 is connected to the positive terminal of the second connection box 4b, and the negative terminal 9b of the second DC input unit 92 is connected to the negative terminal of the second connection box 4b.
  • the second DC input unit 92 is configured to receive the second DC current supplied from the second solar cell string # 2.
  • the positive terminal 9a of the third DC input unit 93 is connected to the positive terminal of the third connection box 4c, and the negative terminal 9b of the third DC input unit 93 is connected to the negative terminal of the third connection box 4c.
  • the third DC input unit 93 is configured to receive a third DC current supplied from the third solar cell string # 3.
  • the first current detector 10a is provided at a stage subsequent to the fuse 7 in the first DC input unit 91.
  • the first current detector 10a detects a current flowing via the first DC input unit 91.
  • the first current detector 10a outputs a first detected current value Ist1 , which is a detected current value, to the control unit 20.
  • the second current detector 10b is provided at a stage subsequent to the fuse 7 in the second DC input unit 92.
  • the second current detector 10b detects a current flowing via the second DC input unit 92.
  • the second current detector 10b outputs a second detected current value Ist2 , which is a detected current value, to the control unit 20.
  • the third current detector 10c is provided after the fuse 7 in the third DC input unit 93.
  • the third current detector 10c detects a current flowing through the third DC input unit 93.
  • the third current detector 10c outputs a third detected current value Ist3 , which is the detected current value, to the control unit 20.
  • the direction of the current flowing into the input side of the power conversion circuit 12 is “forward”. In the embodiment, the direction of the current flowing from the input side of the power conversion circuit 12 is referred to as “reverse direction”.
  • the first current detector 10a, the second current detector 10b, and the third current detector 10c measure the forward current flowing into the power conversion circuit 12 as a positive value, and measure the forward current in the opposite direction to the forward current. The current can be measured as a negative value.
  • the DC side circuit breaker 11 is provided on the input side of the power conversion circuit 12.
  • a DC smoothing capacitor 13 is provided between the DC circuit breaker 11 and the power conversion circuit 12.
  • the AC side circuit breaker 15 is provided on the output side of the power conversion circuit 12.
  • An AC filter circuit 14 is provided between the power conversion circuit 12 and the AC circuit breaker 15.
  • the power conversion circuit 12 is an inverter circuit that converts DC power into three-phase AC power.
  • the power conversion circuit 12 is constructed by a plurality of semiconductor switching elements (not shown).
  • the power conversion circuit 12 has a positive input terminal 12a and a negative input terminal 12b.
  • the positive input terminal 12a is connected to the positive DC wiring 61a in the power converter 6.
  • the positive terminal 9a of the first DC input unit 91, the positive terminal 9a of the second DC input unit 92, and the positive terminal 9a of the third DC input unit 93 are connected to the positive DC line 61a.
  • the negative input terminal 12b is connected to the negative DC wiring 61b in the power converter 6.
  • the negative terminal 9b of the first DC input unit 91, the negative terminal 9b of the second DC input unit 92, and the negative terminal 9b of the third DC input unit 93 are connected to the negative DC line 61b.
  • the control unit 20 includes a first short-circuit detection unit 21 and a second short-circuit detection unit 22.
  • the first short-circuit detection unit 21 detects the first positive-negative-electrode short-circuit X1 shown in FIG. 1, it outputs a switch-on signal S1, circuit breaker trip signals S2, S3, and an alarm signal S4a.
  • the first short-circuit detection unit 21 includes a first block 21a, a second block 21b, and a third block 21c.
  • the alarm signal S4a includes an alarm signal S41 output from the first block 21a, an alarm signal S42 output from the second block 21b, and an alarm signal S43 output from the third block 21c.
  • the first positive-negative electrode short-circuit X1 is based on the first current detector 10a, the second current detector 10b, and the third current detector 10c as reference positions, and is closer to the solar cell strings # 1 to # 3 than the reference positions. This is a short circuit between the positive electrode and the negative electrode that occurs. Specifically, between the first connection box 4a and the first DC input section 91, between the second connection box 4b and the second DC input section 92, between the third connection box 4c and the third DC input section 93. The first short-circuit between the positive electrode and the negative electrode X1 occurs in at least one of the two. The first positive-negative electrode short-circuit X1 may occur further on the solar cell strings # 1 to # 3 side than the first connection box 4a to the third connection box 4c.
  • FIG. 1 shows, as an example, a case in which a first positive-negative-electrode short circuit X1 occurs between the first junction box 4a and the first DC input unit 91.
  • the current Ix1 flows to the short-circuit point of the first positive-negative electrode short-circuit X1.
  • the current Ix1 is the sum of the DC currents input from the second DC input unit 92 and the third DC input unit 93.
  • the second short-circuit detecting unit 22 detects the second positive-negative-electrode short-circuit X2 (see FIG. 3 described later), it outputs a switch-on signal S1, circuit breaker trip signals S2 and S3, and an alarm signal S4b.
  • the configuration and operation of the second short-circuit detector 22 will be described later with reference to FIGS.
  • one end of the switch SW is connected to the positive input terminal 12a via the positive DC line 61a.
  • the other end of the switch SW is connected to the negative input terminal 12b via the negative DC line 61b.
  • the switch SW is turned on in response to the switch-on signal S1 output by the first short-circuit detection unit 21. When the switch SW is turned on, the positive input terminal 12a and the negative input terminal 12b conduct.
  • the DC-side circuit breaker 11 is tripped in response to the circuit breaker trip signal S2.
  • the AC side circuit breaker 15 is tripped in response to the circuit breaker trip signal S3.
  • the alarm signal S4a and the alarm signal S4b may be transmitted to a monitoring device (not shown) provided outside the power conversion device 6.
  • a monitoring device not shown
  • an alarm may be displayed on an alarm device (not shown) provided on the housing of the power conversion device 6 or on the periphery thereof.
  • FIG. 2 is a block diagram illustrating the first short-circuit detection unit 21 according to the embodiment.
  • Each of the first block 21a, the second block 21b, and the third block 21c includes a determination value acquisition block 33 and a first comparison block 34.
  • the determination value obtaining block 33 multiplies a predetermined determination reference value Istr by a negative coefficient of minus 1 to obtain a first reverse current determination.
  • a value Iref1a , a second reverse current determination value Iref1b, and a third reverse current determination value Iref1c are calculated.
  • the third reverse current determination value I Ref1c is a value determined from a predetermined determination reference value I str.
  • the first reverse current determination value Iref1a , the second reverse current determination value Iref1b, and the third reverse current determination value Iref1c may be a common value or different values.
  • the first reverse current determination value Iref1a , the second reverse current determination value Iref1b, and the third reverse current determination value Iref1c are determined by the first solar cell string # 1, the second solar cell string # 2, and the third solar cell string # 3 is preferably set based on the rated current according to each power generation capacity. Specifically, when the rated current of the first solar cell string # 1 is 100 A, a reverse current can be permitted if the rated current is equal to or less than the rated current. That is, it is possible to tolerate up to minus 100A.
  • the first reverse current determination value Iref1a may be set to any value within the range of 1 to 2 times the rated current of the first solar cell string # 1.
  • the second reverse current determination value I ref1b and the third reverse current determination value I ref1c can be determined in the same manner as the first reverse current determination value I ref1a .
  • the “first reverse current” is a current flowing through the first DC input unit 91 in a direction opposite to the first DC current output from the first solar cell string # 1.
  • the first reverse current is measured as a negative current in the first current detector 10a.
  • the detection operation of the first block 21a is realized by the following specific logic by considering the direction of current flow, that is, the sign of the detected current value.
  • the first comparison block 34 compares the first reverse current determination value I ref1a with the first detected current value I st1 . When than the first reverse current determination value I Ref1a is first detected current value I st1 becomes small, the output of the first comparator block 34 becomes high.
  • the first reverse current determination value I ref1a is set to minus 200 A by setting the determination reference value I str to 200A.
  • the first detected current value Ist1 becomes, for example, ⁇ 300 A or the like.
  • the first detection current value I st1 has become a large value in the negative side exceeds the negative 200A is the first reverse current determination value I ref1a. That is, a situation occurs in which a reverse current is flowing, and the absolute value of the measured value of the reverse current exceeds the determination reference value.
  • the output of the first comparison block 34 becomes high.
  • the high output of the first comparison block 34 is the first short-circuit detection signal SX1a.
  • the output of the first comparator block 34 is low.
  • the first reverse current determination value I ref1a is set to minus 200A and the measured first detection current value I st1 is minus 100A.
  • the “magnitude of the current flowing in the negative direction, that is, the reverse direction” in the first DC input unit 91 is 100 A, which is determined to be within the allowable range. That is, a situation where the first detection current value I st1 flows largely the opposite direction enough to exceed the first reverse current determination value I Ref1a is not generated. In this case, the output of the first comparison block 34 remains low.
  • the first short-circuit detection signal SX1a is output to the outside of the control unit 20 in the form of the switch-on signal S1, the breaker trip signals S2, S3, and the alarm signal S41 through the output interface of the first block 21a.
  • the alarm signal S41 is a type of the alarm signal S4a, and indicates that a short circuit between the positive electrode and the negative electrode has occurred on the first DC input unit 91 side.
  • the second block 21b is first Two short-circuit detection signals SX1b are output.
  • the second reverse current is a current that flows through the second DC input unit 92 in a direction opposite to the second DC current output by the second solar cell string # 2. Also in the second block 21b, a detection operation taking into account the sign of the current value is constructed in the same manner as in the first block 21a.
  • the second short-circuit detection signal SX1b is output to the outside of the control unit 20 in the form of the switch-on signal S1, the breaker trip signals S2 and S3, and the alarm signal S42 through the output interface of the second block 21b.
  • the alarm signal S42 is a kind of the alarm signal S4a, and indicates that the first positive-negative electrode short-circuit X1 has occurred on the side of the second DC input unit 92.
  • the third block 21c When it is detected based on the third detection current value Ist3 of the third current detector 10c that the magnitude of the third reverse current exceeds the third reverse current determination value Iref1c , the third block 21c performs the third block 21c.
  • a short-circuit detection signal SX1c is output.
  • the third reverse current is a current that flows through the third DC input unit 93 in a direction opposite to the third DC current output by the third solar cell string # 3. Also in the third block 21c, a detection operation taking into account the polarity of the current value is constructed in the same manner as in the first block 21a.
  • the third short-circuit detection signal SX1c is output to the outside of the control unit 20 in the form of the switch-on signal S1, the breaker trip signals S2 and S3, and the alarm signal S43 through the output interface of the third block 21c.
  • the alarm signal S43 is a type of the alarm signal S4a, and indicates that the first positive-negative electrode short-circuit X1 has occurred on the side of the third DC input unit 93.
  • the first short-circuit detection unit 21 can detect whether the direct current is flowing correctly in the forward direction. If the first reverse current flowing in the reverse direction has occurred and the magnitude of the first reverse current exceeds a predetermined reference, the reverse current having a magnitude exceeding the normally assumed range is usually generated. It flows toward the first solar cell string # 1. In this case, it is highly possible that the first positive-negative electrode short-circuit X1 in the first short-circuit mode has occurred on the first solar cell string # 1 side.
  • Such a short-circuit detection principle can be similarly applied to a current flowing through the second DC input unit 92 and the third DC input unit 93.
  • the first short-circuit detection unit 21 can output the first short-circuit detection signal SX1a indicating that the first positive-negative-electrode short-circuit X1 in the first short-circuit mode has occurred. Similarly, the first short-circuit detection unit 21 generates a second short-circuit detection signal indicating that the first positive-negative short-circuit X1 in the first short-circuit mode has occurred in the second DC input unit 92 and the third DC input unit 93. SX1b and the third short-circuit detection signal SX1c can be output.
  • the first short-circuit detection signal SX1a, the second short-circuit detection signal SX1b, and the third short-circuit detection signal SX1c are separately output, the first DC input unit 91, the second DC input unit 92, and the third DC input unit It is also possible to discriminately detect which of 93 has caused the short circuit.
  • FIG. 3 is a circuit diagram showing a configuration of the power conversion device 6 according to the embodiment and a second short-circuit mode. Since the configuration of the power conversion device 6 and the configuration of the photovoltaic power generation system 1 are the same in FIG. 1 and FIG. 3, the description of the configuration is omitted.
  • the second short-circuit mode that is, the second short-circuit between the positive electrode and the negative electrode X2 is a short-circuit that occurs between the positive-electrode DC wiring 61a and the negative-electrode DC wiring 61b.
  • the short-circuit current Ix4 flows to the short-circuit location of the second short-circuit between the positive electrode and the negative electrode X2.
  • the short-circuit current Ix4 is a current obtained by summing the current input from the first DC input unit 91 and the sum of the currents input from the second DC input unit 92 and the third DC input unit 93 (that is, the current Ix1). It is.
  • FIG. 4 is a block diagram illustrating the second short-circuit detection unit 22 according to the embodiment.
  • the second short-circuit detection unit 22 includes a total value calculation block 41, a low-pass filter block 42, a gain block 43, and a second comparison block 44.
  • Total value calculation block 41 by adding the first detected current value I st1 and the second detected current value I st2 and a third detected current value I st3, calculates a total current value I stsum.
  • the total current value Istsum is input to the second comparison block 44 and the low-pass filter block 42.
  • the low-pass filter block 42 can dampen the change so as not to transmit the change to the subsequent circuit.
  • the time constant of the low-pass filter block 42 is set to a value that allows a gradual change in current caused by fluctuations in solar radiation to pass, and is set to an appropriate value that can prevent a sudden change in current when a short circuit occurs.
  • the gain block 43 multiplies the input value by a predetermined gain coefficient K.
  • the low-pass filter block 42 performs filtering on the total current value I stsum .
  • the value passed through the low-pass filter block 42 is multiplied by a gain coefficient K in a gain block 43.
  • the gain coefficient may be set to any value within a range of 1.1 to 1.5, for example.
  • the gain block 43 is preferably constructed so that the gain coefficient K can be variably set afterwards.
  • the calculated value multiplied by the gain coefficient K is input to the second comparison block 44 as the total determination value I sumref .
  • FIG. 5 is a diagram for explaining the operation of the second short-circuit detection unit 22 according to the embodiment.
  • a schematic graph of the total current value I stsum is shown by a solid line, and the corresponding total determination value I sumref is shown by a broken line.
  • the gradual fluctuation of the total current value I stsum schematically represents the solar radiation fluctuation. Since the low-pass filter block 42 allows the current change due to the solar radiation fluctuation, the total current value I stsum and the total determination value I sumref gradually change in the same tendency.
  • the low-pass filter block 42 blocks a steep change in the total current value I stsum at the time tx. Therefore, even at time tx, the total determination value I sumref holds the value immediately before the occurrence of the short circuit. Since the total current value I Stsum total determination value I Sumref Whereas constant increases sharply, points total current value I Stsum indicated by reference numeral Q increases beyond the total judgment value I sumref.
  • the second comparison block 44 compares the total current value Istsum with the total determination value Isumref .
  • the output of the first comparison block 34 is low.
  • the output of the second comparison block 44 becomes high. That is, the total current value I sumsum exceeds the total determination value I sumref to the plus side.
  • the high output of the second comparison block 44 is the short-circuit detection signal SX2.
  • the second short-circuit detection unit 22 can determine whether or not the size is appropriate. If the magnitude of the total current exceeds a predetermined reference, a current larger than the original current flows to the power conversion circuit 12 side. In this case, there is a high possibility that the second short-circuit between the positive electrode and the negative electrode in the second short-circuit mode X2 has occurred in the previous stage of the power conversion circuit 12. Therefore, the second short-circuit detection unit 22 can output the short-circuit detection signal SX2 indicating that the second short-circuit between the positive electrode and the negative electrode X2 in the second short-circuit mode has occurred.
  • the provision of the low-pass filter block 42 and the gain block 43 also has the following advantages.
  • the number of solar cell strings # 1 to # 3 and the current value for each solar cell string differ for each power system.
  • different power systems also have different appropriate sum determination values I sumref for determining the total current.
  • an appropriate total determination value I sumref is calculated by performing an operation on the total current value I stsum by the low-pass filter block 42 and the gain block 43.
  • the gain coefficient K is 1.1 to 1.5, a value 1.1 to 1.5 times the actually input total current value I stsum is used as the total determination value I sumref . Can be set. As a result, even if the current flowing at the time of the short circuit between the positive electrode and the negative electrode is small, the second short circuit X2 between the positive electrode and the negative electrode can be detected quickly and accurately.
  • Gain coefficient K can be set to any value greater than one.
  • the switch SW is turned on in response to the switch-on signal S1 output from the second short-circuit detection unit 22.
  • a path for flowing a short-circuit current can be intentionally created, so that the current flowing to the generated short-circuit portion can be reduced. Therefore, the protection function is perfect for both the first short-circuit mode and the second short-circuit mode.
  • the control unit 20 switches at least one of the DC-side circuit breaker 11 and the AC-side circuit breaker 15. It is built to trip. Therefore, the protection function can be further improved.
  • the control unit 20 includes both the first short-circuit detection unit 21 and the second short-circuit detection unit 22. Therefore, the first short-circuit between the positive electrode and the negative electrode X1 in the first short-circuit mode and the second short-circuit between the positive electrode and the negative electrode X2 in the second short-circuit mode can be detected separately.
  • an alarm signal S4a (more specifically, S41, S42, S43) is output according to the first positive-negative short-circuit X1
  • an alarm signal S4b is output according to the second positive-negative short-circuit X2. .
  • a band-pass filter block may be used instead of the low-pass filter block 42 in FIG.
  • This band-pass filter block may be provided with a filter function for blocking a signal in a high-frequency range similarly to the low-pass filter block 42.
  • the order of the low-pass filter block 42 and the gain block 43 may be opposite to that in FIG. 4, that is, the gain block 43 may be in the preceding stage.
  • FIG. 6 is a block diagram illustrating a second short-circuit detection unit 22 according to a modification of the embodiment.
  • the determination value setting unit 143 stores the total determination value I sumref in a rewritable manner.
  • the total determination value I sumref is a fixed value or a variable set value determined independently of the total current value I stsum .
  • the power conversion device 6 including only one of the first short-circuit detection unit 21 and the second short-circuit detection unit 22 may be provided.
  • a solar power generation system 1 including three solar cell strings # 1 to # 3 is provided.
  • the number of solar cell strings is not limited to three.
  • the number of solar cell strings may be one, two, or four or more.
  • the above-described various determination values may be adjusted according to the number of connected solar cell strings.
  • FIG. 7 is a configuration example of the control unit 20 according to the embodiment.
  • FIG. 7 is a hardware configuration diagram applicable to the control unit 20 according to the embodiment of the present invention. As shown in FIG. 7, each function of the control unit 20 can be realized by the processing circuit 50.
  • the processing circuit 50 includes a processor 51 and a memory 52.
  • the processor 51 is a CPU (Central Processing Unit) such as a central processing unit, a processing unit, a microprocessor, a microcomputer, a processor, or a DSP.
  • the memory 52 is a non-volatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, an EEPROM, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, and a DVD.
  • a program stored in the memory 52 is executed by the processor 51.
  • the power conversion device 6 is not limited to only the photovoltaic power generation use.
  • a constant current power source other than a solar cell may be connected to the power converter 6.
  • Reference Signs List 1 solar power generation system # 1 first solar cell string, # 2 second solar cell string, # 3 third solar cell string, 2a, 2b, 2c solar panel, 4a first connection box, 4b second connection box 4c third connection box, 6 power converter, 7 fuse, 9a positive terminal, 9b negative terminal, 10a first current detector, 10b second current detector, 10c third current detector, 11 DC circuit breaker, Reference Signs List 12 power conversion circuit, 12a positive input terminal, 12b negative input terminal, 13 DC smoothing capacitor, 14 AC filter circuit, 15 AC circuit breaker, 16 transformer, 17 power system, 20 control unit, 21 first short circuit detection unit, 21a first block, 21b second block, 21c third block, 22 second short circuit detector, 33 judgment value acquisition block, 34 first comparison block, 41 total value calculation block Block, 42 low-pass filter block, 43 gain block, 44 second comparison block, 50 processing circuit, 51 processor, 52 memory, 61a positive DC wiring, 61b negative DC wiring, 91 first DC input section, 92 second DC Input unit, 93 third DC input

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Abstract

This power conversion device comprises: a first DC input unit constructed to be able to receive a first DC current; a power conversion circuit that outputs AC current by converting the first DC current input from the first DC input unit; a first current detector provided in the first DC input unit; and a short circuit detection unit constructed to output a first short circuit detection signal when it is detected that the size of a first reverse current that flows through the first DC input unit in the reverse direction to the first DC current exceeds a first judgment value on the basis of the output of the first current detector. The power conversion device may also further comprise: a second DC input unit that can receive a second DC current; and a second current detector provided in the second DC input unit. The short circuit detection unit may also be constructed to output a second short circuit detection signal when it is detected that the size of a second reverse current that flows through the second DC input unit in the reverse direction to the second DC current exceeds a preset second judgment value on the basis of the output of the second current detector.

Description

電力変換装置Power converter
　本発明は、電力変換装置に関するものである。 The present invention relates to a power conversion device.
　従来、例えば日本特開２０１３－８０７３１号公報に開示されているように、太陽電池ストリングに電流計が設けられた電力変換システムが知られている。特に、上記公報の図９では、複数の太陽電池ストリングスが設けられており、太陽電池ストリングそれぞれに電流計を設ける構成が記載されている。 Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 2013-80731, for example, a power conversion system in which an ammeter is provided in a solar cell string is known. In particular, FIG. 9 of the above publication describes a configuration in which a plurality of solar cell strings are provided, and an ammeter is provided for each of the solar cell strings.
日本特開２０１３－８０７３１号公報Japanese Patent Application Laid-Open No. 2013-80731
　一般的に、電力システムにおいて正極負極間に短絡が起きると、その短絡箇所を通じて大電流が流れる。この大電流は、一般にヒューズ等の保護素子によって遮断される。 Generally, when a short circuit occurs between the positive electrode and the negative electrode in a power system, a large current flows through the short circuit. This large current is generally cut off by a protection element such as a fuse.
　しかしながら、太陽電池あるいは他の定電流電源を持つ電力システムにおいては、他の一般的な電力システムと比べて、回路内で正極負極間に短絡が起きた場合に流れる電流が、定格運用時の電流から大きく増加しない。このため、短絡の検出が難しいという問題があった。短絡時に流れる電流が大きく変化しないこの種の電力システムにおいては、正極負極間短絡に対する保護を万全にする観点から、いまだ改良の余地があった。 However, in a power system having a solar cell or other constant current power supply, the current flowing when a short circuit occurs between the positive electrode and the negative electrode in the circuit, compared to other general power systems, is the current during rated operation. Does not increase significantly from For this reason, there is a problem that it is difficult to detect a short circuit. In this type of power system in which the current flowing during a short circuit does not change significantly, there is still room for improvement from the viewpoint of thorough protection against a short circuit between the positive electrode and the negative electrode.
　本発明は、上述のような課題を解決するためになされたもので、正極負極間の短絡を検出する機能を備えた電力変換装置を提供することを目的とする。 The present invention has been made to solve the above-described problems, and has as its object to provide a power converter having a function of detecting a short circuit between a positive electrode and a negative electrode.
　本出願にかかる第一の電力変換装置は、
　第一直流電流を受け入れ可能に構築された第一直流入力部と、
　前記第一直流入力部から入力された前記第一直流電流を変換することで交流電流を出力する電力変換回路と、
　前記第一直流入力部に設けられた第一電流検出器と、
　前記第一直流入力部を通じて前記第一直流電流と逆方向へと流れる第一逆電流の大きさが第一判定値を超えたことが前記第一電流検出器の出力に基づいて検出された場合に、第一短絡検出信号を出力するように構築された短絡検出部と、
　を備える。 The first power converter according to the present application is:
A first DC input unit constructed to accept the first DC current,
A power conversion circuit that outputs an AC current by converting the first DC current input from the first DC input unit,
A first current detector provided in the first DC input unit,
It was detected based on the output of the first current detector that the magnitude of the first reverse current flowing in the opposite direction to the first DC current through the first DC input section exceeded a first determination value. In the case, a short-circuit detection unit configured to output a first short-circuit detection signal,
Is provided.
　本出願にかかる第二の電力変換装置は、
　第一直流電流を受け入れ可能に構築された第一直流入力部と、
　第二直流電流を受け入れ可能に構築された第二直流入力部と、
　前記第一直流入力部および前記第二直流入力部のそれぞれの正極に接続された正極入力端と、前記第一直流入力部および前記第二直流入力部のそれぞれの負極に接続された負極入力端と、を有する電力変換回路と、
　前記第一直流入力部に設けられた第一電流検出器と、
　前記第二直流入力部に設けられた第二電流検出器と、
　前記第一電流検出器で検出した電流値と前記第二電流検出器で検出した電流値とを合計した合計電流値が判定値を超えた場合には、短絡検出信号を出力するように構築された短絡検出部と、
　を備える。 The second power converter according to the present application is:
A first DC input unit constructed to accept the first DC current,
A second DC input unit configured to accept a second DC current,
A positive input terminal connected to each positive electrode of the first DC input unit and the second DC input unit, and a negative electrode connected to each negative electrode of the first DC input unit and the second DC input unit A power conversion circuit having an input end;
A first current detector provided in the first DC input unit,
A second current detector provided in the second DC input unit,
If the total current value obtained by summing the current value detected by the first current detector and the current value detected by the second current detector exceeds the determination value, a short-circuit detection signal is output. Short-circuit detection unit,
Is provided.
　上記第一の電力変換装置によれば、次の効果が得られる。第一直流入力部を介して第一太陽電池ストリングからの第一直流電流を受け入れたときに、この第一直流電流が正しく順方向に流れているかどうかを短絡検出部が検出することができる。もし、逆方向へと流れる第一逆電流が発生しており、しかもその第一逆電流の大きさが基準となる大きさを超えている場合には、通常想定範囲を超える大きさの逆電流が第一太陽電池ストリングスの側へと流れている。この場合には、第一太陽電池ストリングの側での短絡である第一正極負極間短絡が発生している可能性が高い。そこで、短絡検出部はそのような第一正極負極間短絡が発生したことを示す短絡検出信号を出力することができる。 According to the first power converter, the following effects can be obtained. When the first DC current from the first solar cell string is received via the first DC input unit, the short-circuit detection unit can detect whether the first DC current is correctly flowing in the forward direction. . If the first reverse current flowing in the reverse direction is generated, and the magnitude of the first reverse current exceeds the reference level, the reverse current having a magnitude exceeding the normal range is usually assumed. Flows toward the first solar cell strings. In this case, there is a high possibility that a short circuit between the first positive electrode and the negative electrode, which is a short circuit on the first solar cell string side, has occurred. Therefore, the short-circuit detection unit can output a short-circuit detection signal indicating that such a short circuit between the first positive electrode and the negative electrode has occurred.
　上記第二の電力変換装置によれば、次の効果が得られる。第一直流入力部と第二直流入力部とを介して第一太陽電池ストリングおよび第二太陽電池ストリングそれぞれからの電流を受け入れたときに、それらの合計電流の大きさが適正であるかを短絡検出部が判定することができる。もし、合計電流の大きさが基準となる大きさを超えている場合には、通常想定範囲を超える大きさの電流が電力変換回路の側へと流れている。この場合には、電力変換回路の正極と負極とが短絡した第二正極負極間短絡が発生している可能性が高い。そこで、短絡検出部はそのような第二正極負極間短絡が発生したことを示す短絡検出信号を出力することができる。 According to the second power converter, the following effects can be obtained. When the current from each of the first solar cell string and the second solar cell string is received via the first DC input section and the second DC input section, it is determined whether the magnitude of the total current is appropriate. The short-circuit detector can make the determination. If the magnitude of the total current exceeds the reference level, a current having a magnitude exceeding the normal range usually flows toward the power conversion circuit. In this case, there is a high possibility that a short circuit between the second positive electrode and the negative electrode, in which the positive electrode and the negative electrode of the power conversion circuit are short-circuited, has occurred. Thus, the short-circuit detection unit can output a short-circuit detection signal indicating that such a short circuit between the second positive electrode and the negative electrode has occurred.
実施の形態にかかる電力変換装置の構成および第一短絡モードを示す回路図である。FIG. 2 is a circuit diagram showing a configuration of a power converter according to the embodiment and a first short-circuit mode. 実施の形態にかかる第一短絡検出部を示すブロック図である。FIG. 3 is a block diagram illustrating a first short-circuit detection unit according to the embodiment. 実施の形態にかかる電力変換装置の構成および第二短絡モードを示す回路図である。FIG. 3 is a circuit diagram illustrating a configuration of a power conversion device according to the embodiment and a second short-circuit mode. 実施の形態にかかる第二短絡検出部を示すブロック図である。FIG. 4 is a block diagram illustrating a second short-circuit detection unit according to the embodiment. 実施の形態にかかる第二短絡検出部の動作を説明するための図である。FIG. 6 is a diagram for explaining an operation of the second short-circuit detection unit according to the embodiment. 実施の形態の変形例にかかる第二短絡検出部を示すブロック図である。FIG. 10 is a block diagram illustrating a second short-circuit detection unit according to a modification of the embodiment. 実施の形態にかかる制御部の構成例である。4 is a configuration example of a control unit according to the embodiment.
　実施の形態では、２つの異なる短絡モードが検出される。「第一短絡モード」は、図１に示す第一正極負極間短絡Ｘ１が発生したモードである。「第二短絡モード」は、図３に示す第二正極負極間短絡Ｘ２が発生したモードである。 In the embodiment, two different short-circuit modes are detected. The “first short-circuit mode” is a mode in which the first positive-negative-electrode short-circuit X1 shown in FIG. 1 has occurred. The “second short-circuit mode” is a mode in which the second short-circuit between the positive electrode and the negative electrode X2 illustrated in FIG. 3 has occurred.
［実施の形態のシステム構成および第一短絡モード］
　図１は、実施の形態にかかる電力変換装置６の構成および第一短絡モードを示す回路図である。図１には、電力変換装置６を含む太陽光発電システム１も図示されている。 [System Configuration and First Short-Circuit Mode of Embodiment]
FIG. 1 is a circuit diagram showing a configuration of a power conversion device 6 according to the embodiment and a first short-circuit mode. FIG. 1 also shows a photovoltaic power generation system 1 including a power converter 6.
　まず、図１を参照して太陽光発電システム１および電力変換装置６の構成を説明する。太陽光発電システム１は、第一太陽電池ストリング＃１と、第二太陽電池ストリング＃２と、第三太陽電池ストリング＃３と、第一接続箱４ａと、第二接続箱４ｂと、第三接続箱４ｃと、電力変換装置６と、変圧器１６と、を備えている。 First, the configurations of the photovoltaic power generation system 1 and the power conversion device 6 will be described with reference to FIG. The solar power generation system 1 includes a first solar cell string # 1, a second solar cell string # 2, a third solar cell string # 3, a first connection box 4a, a second connection box 4b, and a third It includes a connection box 4c, a power conversion device 6, and a transformer 16.
　第一太陽電池ストリング＃１は、複数の太陽電池パネル２ａを含んでいる。複数の太陽電池パネル２ａそれぞれが出力する第一直流電流は、第一接続箱４ａの内部で合流する。 The first solar cell string # 1 includes a plurality of solar cell panels 2a. The first direct current output from each of the plurality of solar cell panels 2a joins inside the first connection box 4a.
　第二太陽電池ストリング＃２は、複数の太陽電池パネル２ｂを含んでいる。複数の太陽電池パネル２ｂそれぞれが出力する第二直流電流は、第二接続箱４ｂの内部で合流する。 The second solar cell string # 2 includes a plurality of solar cell panels 2b. The second direct current output from each of the plurality of solar cell panels 2b joins inside the second connection box 4b.
　第三太陽電池ストリング＃３は、複数の太陽電池パネル２ｃを含んでいる。複数の太陽電池パネル２ｃそれぞれが出力する第三直流電流は、第三接続箱４ｃの内部で合流する。 The third solar cell string # 3 includes a plurality of solar cell panels 2c. The third direct current output from each of the plurality of solar cell panels 2c joins inside the third connection box 4c.
　以下、第一太陽電池ストリング＃１と第二太陽電池ストリング＃２と第三太陽電池ストリング＃３とをまとめて「太陽電池ストリングス＃１～＃３」と称することもある。 Hereinafter, the first solar cell string # 1, the second solar cell string # 2, and the third solar cell string # 3 may be collectively referred to as "solar cell strings # 1 to # 3".
　太陽光発電システム１は、太陽電池ストリングス＃１～＃３で発電された直流電力を電力変換装置６で交流電力に変換する。太陽光発電システム１は電力系統１７と系統連系運転されている。電力変換装置６で変換された交流電力は、電力系統１７に供給される。 (4) The solar power generation system 1 converts the DC power generated by the solar cell strings # 1 to # 3 into AC power by the power converter 6. The photovoltaic power generation system 1 is connected to the power system 17 in a system interconnection operation. The AC power converted by the power converter 6 is supplied to the power system 17.
　図１に示すように、電力変換装置６は、第一直流入力部９１と、第二直流入力部９２と、第三直流入力部９３と、第一電流検出器１０ａと、第二電流検出器１０ｂと、第三電流検出器１０ｃと、直流側遮断器１１と、電力変換回路１２と、直流平滑コンデンサ１３と、スイッチＳＷと、交流フィルタ回路１４と、交流側遮断器１５と、制御部２０と、を備える。 As shown in FIG. 1, the power conversion device 6 includes a first DC input unit 91, a second DC input unit 92, a third DC input unit 93, a first current detector 10a, and a second current detection unit. , A third current detector 10c, a DC side circuit breaker 11, a power conversion circuit 12, a DC smoothing capacitor 13, a switch SW, an AC filter circuit 14, an AC side circuit breaker 15, and a control unit. 20.
　第一直流入力部９１と第二直流入力部９２と第三直流入力部９３それぞれは、正極端子９ａと負極端子９ｂとを備えている。第一直流入力部９１と第二直流入力部９２と第三直流入力部９３それぞれの内部には、ヒューズ７が設けられている。第一接続箱４ａと第二接続箱４ｂと第三接続箱４ｃの内部にも、ヒューズ７が設けられている。 The first DC input unit 91, the second DC input unit 92, and the third DC input unit 93 each include a positive terminal 9a and a negative terminal 9b. The fuse 7 is provided inside each of the first DC input unit 91, the second DC input unit 92, and the third DC input unit 93. A fuse 7 is also provided inside the first connection box 4a, the second connection box 4b, and the third connection box 4c.
　第一直流入力部９１の正極端子９ａと第一接続箱４ａの正極とが接続され、第一直流入力部９１の負極端子９ｂと第一接続箱４ａの負極とが接続されている。第一直流入力部９１は、第一太陽電池ストリング＃１から供給される第一直流電流を受け入れ可能に構築されている。 (4) The positive terminal 9a of the first DC input unit 91 is connected to the positive terminal of the first connection box 4a, and the negative terminal 9b of the first DC input unit 91 is connected to the negative terminal of the first connection box 4a. The first DC input unit 91 is configured to receive the first DC current supplied from the first solar cell string # 1.
　第二直流入力部９２の正極端子９ａと第二接続箱４ｂの正極とが接続され、第二直流入力部９２の負極端子９ｂと第二接続箱４ｂの負極とが接続されている。第二直流入力部９２は、第二太陽電池ストリング＃２から供給される第二直流電流を受け入れ可能に構築されている。 (4) The positive terminal 9a of the second DC input unit 92 is connected to the positive terminal of the second connection box 4b, and the negative terminal 9b of the second DC input unit 92 is connected to the negative terminal of the second connection box 4b. The second DC input unit 92 is configured to receive the second DC current supplied from the second solar cell string # 2.
　第三直流入力部９３の正極端子９ａと第三接続箱４ｃの正極とが接続され、第三直流入力部９３の負極端子９ｂと第三接続箱４ｃの負極とが接続されている。第三直流入力部９３は、第三太陽電池ストリング＃３から供給される第三直流電流を受け入れ可能に構築されている。 (4) The positive terminal 9a of the third DC input unit 93 is connected to the positive terminal of the third connection box 4c, and the negative terminal 9b of the third DC input unit 93 is connected to the negative terminal of the third connection box 4c. The third DC input unit 93 is configured to receive a third DC current supplied from the third solar cell string # 3.
　第一電流検出器１０ａは、第一直流入力部９１におけるヒューズ７の後段に設けられている。第一電流検出器１０ａは、第一直流入力部９１を経由して流れる電流を検出する。第一電流検出器１０ａは、検出した電流値である第一検出電流値Ｉｓｔ１を制御部２０に出力する。 The first current detector 10a is provided at a stage subsequent to the fuse 7 in the first DC input unit 91. The first current detector 10a detects a current flowing via the first DC input unit 91. The first current detector 10a outputs a first detected current value Ist1 , which is a detected current value, to the control unit 20.
　第二電流検出器１０ｂは、第二直流入力部９２におけるヒューズ７の後段に設けられている。第二電流検出器１０ｂは、第二直流入力部９２を経由して流れる電流を検出する。第二電流検出器１０ｂは、検出した電流値である第二検出電流値Ｉｓｔ２を制御部２０に出力する。 The second current detector 10b is provided at a stage subsequent to the fuse 7 in the second DC input unit 92. The second current detector 10b detects a current flowing via the second DC input unit 92. The second current detector 10b outputs a second detected current value Ist2 , which is a detected current value, to the control unit 20.
　第三電流検出器１０ｃは、第三直流入力部９３におけるヒューズ７の後段に設けられている。第三電流検出器１０ｃは、第三直流入力部９３を経由して流れる電流を検出する。第三電流検出器１０ｃは、検出した電流値である第三検出電流値Ｉｓｔ３を制御部２０に出力する。 The third current detector 10c is provided after the fuse 7 in the third DC input unit 93. The third current detector 10c detects a current flowing through the third DC input unit 93. The third current detector 10c outputs a third detected current value Ist3 , which is the detected current value, to the control unit 20.
　実施の形態では、電力変換回路１２の入力側へと流れ込む電流の向きを、「順方向」とする。実施の形態では、電力変換回路１２の入力側から流れ出る電流の向きを、「逆方向」とする。第一電流検出器１０ａと第二電流検出器１０ｂと第三電流検出器１０ｃは、電力変換回路１２の側へと流れ込む順電流をプラスの値として計測し、この順電流とは逆方向の逆電流をマイナスの値として計測することができる。 In the embodiment, the direction of the current flowing into the input side of the power conversion circuit 12 is “forward”. In the embodiment, the direction of the current flowing from the input side of the power conversion circuit 12 is referred to as “reverse direction”. The first current detector 10a, the second current detector 10b, and the third current detector 10c measure the forward current flowing into the power conversion circuit 12 as a positive value, and measure the forward current in the opposite direction to the forward current. The current can be measured as a negative value.
　直流側遮断器１１は、電力変換回路１２の入力側に設けられている。直流側遮断器１１と電力変換回路１２との間に、直流平滑コンデンサ１３が設けられている。交流側遮断器１５は、電力変換回路１２の出力側に設けられている。電力変換回路１２と交流側遮断器１５との間に、交流フィルタ回路１４が設けられている。 The DC side circuit breaker 11 is provided on the input side of the power conversion circuit 12. A DC smoothing capacitor 13 is provided between the DC circuit breaker 11 and the power conversion circuit 12. The AC side circuit breaker 15 is provided on the output side of the power conversion circuit 12. An AC filter circuit 14 is provided between the power conversion circuit 12 and the AC circuit breaker 15.
　電力変換回路１２は、直流電力を三相交流電力に変換するインバータ回路である。電力変換回路１２は、図示しない複数の半導体スイッチング素子などによって構築されている。電力変換回路１２は、正極入力端１２ａと負極入力端１２ｂとを備える。 The power conversion circuit 12 is an inverter circuit that converts DC power into three-phase AC power. The power conversion circuit 12 is constructed by a plurality of semiconductor switching elements (not shown). The power conversion circuit 12 has a positive input terminal 12a and a negative input terminal 12b.
　正極入力端１２ａは、電力変換装置６内の正極直流配線６１ａと接続している。正極直流配線６１ａには、第一直流入力部９１の正極端子９ａ、第二直流入力部９２の正極端子９ａ、および第三直流入力部９３の正極端子９ａが接続されている。 The positive input terminal 12a is connected to the positive DC wiring 61a in the power converter 6. The positive terminal 9a of the first DC input unit 91, the positive terminal 9a of the second DC input unit 92, and the positive terminal 9a of the third DC input unit 93 are connected to the positive DC line 61a.
　負極入力端１２ｂは、電力変換装置６内の負極直流配線６１ｂと接続している。負極直流配線６１ｂには、第一直流入力部９１の負極端子９ｂ、第二直流入力部９２の負極端子９ｂ、および第三直流入力部９３の負極端子９ｂが接続されている。 The negative input terminal 12b is connected to the negative DC wiring 61b in the power converter 6. The negative terminal 9b of the first DC input unit 91, the negative terminal 9b of the second DC input unit 92, and the negative terminal 9b of the third DC input unit 93 are connected to the negative DC line 61b.
　電力変換回路１２は、第一直流入力部９１、第二直流入力部９２、および第三直流入力部９３を介して入力された第一直流電流～第三直流電流を変換することで、交流電流を出力する。 The power conversion circuit 12 converts the first DC current to the third DC current input through the first DC input unit 91, the second DC input unit 92, and the third DC input unit 93, thereby obtaining AC power. Outputs current.
　制御部２０は、第一短絡検出部２１と、第二短絡検出部２２とを備える。第一短絡検出部２１は、図１に示す第一正極負極間短絡Ｘ１を検出すると、スイッチオン信号Ｓ１、遮断器トリップ信号Ｓ２、Ｓ３、およびアラーム信号Ｓ４ａを出力する。 The control unit 20 includes a first short-circuit detection unit 21 and a second short-circuit detection unit 22. When the first short-circuit detection unit 21 detects the first positive-negative-electrode short-circuit X1 shown in FIG. 1, it outputs a switch-on signal S1, circuit breaker trip signals S2, S3, and an alarm signal S4a.
　より詳細には、第一短絡検出部２１は、第一ブロック２１ａと、第二ブロック２１ｂと、第三ブロック２１ｃと、を含んでいる。アラーム信号Ｓ４ａには、第一ブロック２１ａで出力されるアラーム信号Ｓ４１と、第二ブロック２１ｂで出力されるアラーム信号Ｓ４２と、第三ブロック２１ｃで出力されるアラーム信号Ｓ４３とが含まれる。 More specifically, the first short-circuit detection unit 21 includes a first block 21a, a second block 21b, and a third block 21c. The alarm signal S4a includes an alarm signal S41 output from the first block 21a, an alarm signal S42 output from the second block 21b, and an alarm signal S43 output from the third block 21c.
　第一正極負極間短絡Ｘ１は、第一電流検出器１０ａ、第二電流検出器１０ｂおよび第三電流検出器１０ｃを基準位置として、この基準位置よりも太陽電池ストリングス＃１～＃３の側に発生する正極負極間短絡である。具体的には、第一接続箱４ａと第一直流入力部９１との間、第二接続箱４ｂと第二直流入力部９２との間、第三接続箱４ｃと第三直流入力部９３との間の少なくとも１つに、第一正極負極間短絡Ｘ１が発生する。第一接続箱４ａ～第三接続箱４ｃよりもさらに太陽電池ストリングス＃１～＃３の側に、第一正極負極間短絡Ｘ１が発生することもある。 The first positive-negative electrode short-circuit X1 is based on the first current detector 10a, the second current detector 10b, and the third current detector 10c as reference positions, and is closer to the solar cell strings # 1 to # 3 than the reference positions. This is a short circuit between the positive electrode and the negative electrode that occurs. Specifically, between the first connection box 4a and the first DC input section 91, between the second connection box 4b and the second DC input section 92, between the third connection box 4c and the third DC input section 93. The first short-circuit between the positive electrode and the negative electrode X1 occurs in at least one of the two. The first positive-negative electrode short-circuit X1 may occur further on the solar cell strings # 1 to # 3 side than the first connection box 4a to the third connection box 4c.
　図１では、一例として、第一接続箱４ａと第一直流入力部９１との間に第一正極負極間短絡Ｘ１が発生した場合を示している。図１のように第一正極負極間短絡Ｘ１が発生すると、第一正極負極間短絡Ｘ１の短絡箇所へと電流Ｉｘ１が流れる。電流Ｉｘ１は、第二直流入力部９２および第三直流入力部９３から入力される直流電流の合計である。 FIG. 1 shows, as an example, a case in which a first positive-negative-electrode short circuit X1 occurs between the first junction box 4a and the first DC input unit 91. When the first positive-negative electrode short-circuit X1 occurs as shown in FIG. 1, the current Ix1 flows to the short-circuit point of the first positive-negative electrode short-circuit X1. The current Ix1 is the sum of the DC currents input from the second DC input unit 92 and the third DC input unit 93.
　第一短絡検出部２１の構成および動作の詳細は、後ほど図２を用いて説明する。 The details of the configuration and operation of the first short-circuit detection unit 21 will be described later with reference to FIG.
　第二短絡検出部２２は、第二正極負極間短絡Ｘ２（後述の図３参照）を検出すると、スイッチオン信号Ｓ１、遮断器トリップ信号Ｓ２、Ｓ３、およびアラーム信号Ｓ４ｂを出力する。第二短絡検出部２２の構成及び動作は、図３および図４を用いて後ほど説明する。 When the second short-circuit detecting unit 22 detects the second positive-negative-electrode short-circuit X2 (see FIG. 3 described later), it outputs a switch-on signal S1, circuit breaker trip signals S2 and S3, and an alarm signal S4b. The configuration and operation of the second short-circuit detector 22 will be described later with reference to FIGS.
　図１に示すように、スイッチＳＷの一端は、正極直流配線６１ａを介して正極入力端１２ａに接続されている。スイッチＳＷの他端は、負極直流配線６１ｂを介して負極入力端１２ｂに接続されている。スイッチＳＷは、第一短絡検出部２１が出力したスイッチオン信号Ｓ１に応答してターンオンされる。スイッチＳＷがターンオンされると、正極入力端１２ａと負極入力端１２ｂとが導通する。 (1) As shown in FIG. 1, one end of the switch SW is connected to the positive input terminal 12a via the positive DC line 61a. The other end of the switch SW is connected to the negative input terminal 12b via the negative DC line 61b. The switch SW is turned on in response to the switch-on signal S1 output by the first short-circuit detection unit 21. When the switch SW is turned on, the positive input terminal 12a and the negative input terminal 12b conduct.
　第一短絡モードの第一正極負極間短絡Ｘ１が発生した時にスイッチＳＷがオンされることで、短絡経路を避けて意図的に電流を流すための「他の電流経路」を作り出すことができる。仮にスイッチＳＷがオフのままだと、電流Ｉｘ１が第一正極負極間短絡Ｘ１へと向かうことで短絡電流Ｉｘ２が流れてしまう。この点、実施の形態ではスイッチＳＷを経由して図１の電流Ｉｘ３の流れを作り出すように、電流Ｉｘ１を流すことができる。その結果、第一正極負極間短絡Ｘ１で生じた短絡経路に短絡電流Ｉｘ２が流れることを抑制することができる。 (4) By turning on the switch SW when the first positive-negative-electrode short-circuit X1 in the first short-circuit mode occurs, it is possible to create “another current path” for intentionally flowing a current avoiding the short-circuit path. If the switch SW is kept off, the current Ix1 flows toward the first positive-negative-electrode short-circuit X1, and the short-circuit current Ix2 flows. In this regard, in the embodiment, the current Ix1 can be caused to flow through the switch SW so as to generate the current Ix3 in FIG. As a result, it is possible to suppress the short-circuit current Ix2 from flowing through the short-circuit path generated by the first positive-negative-electrode short-circuit X1.
　遮断器トリップ信号Ｓ２に応答して、直流側遮断器１１がトリップされる。遮断器トリップ信号Ｓ３に応答して、交流側遮断器１５がトリップされる。これにより、短絡発生時に保護動作を実施することができる。 直流 The DC-side circuit breaker 11 is tripped in response to the circuit breaker trip signal S2. The AC side circuit breaker 15 is tripped in response to the circuit breaker trip signal S3. Thus, a protection operation can be performed when a short circuit occurs.
　アラーム信号Ｓ４ａおよびアラーム信号Ｓ４ｂは、電力変換装置６の外部に設けられた監視装置（図示せず）に伝達されてもよい。アラーム信号Ｓ４ａおよびアラーム信号Ｓ４ｂに応答して、電力変換装置６の筐体あるいは周囲に設けられた警報機器（図示せず）にアラーム表示が行われても良い。 (4) The alarm signal S4a and the alarm signal S4b may be transmitted to a monitoring device (not shown) provided outside the power conversion device 6. In response to the alarm signal S4a and the alarm signal S4b, an alarm may be displayed on an alarm device (not shown) provided on the housing of the power conversion device 6 or on the periphery thereof.
［実施の形態の第一短絡検出部の構成］
　図２は、実施の形態にかかる第一短絡検出部２１を示すブロック図である。第一ブロック２１ａと第二ブロック２１ｂと第三ブロック２１ｃは、それぞれ判定値取得ブロック３３と、第一比較ブロック３４と、を備えている。 [Configuration of First Short Circuit Detection Unit of Embodiment]
FIG. 2 is a block diagram illustrating the first short-circuit detection unit 21 according to the embodiment. Each of the first block 21a, the second block 21b, and the third block 21c includes a determination value acquisition block 33 and a first comparison block 34.
　第一ブロック２１ａと第二ブロック２１ｂと第三ブロック２１ｃそれぞれにおいて、判定値取得ブロック３３は、予め定めた判定基準値Ｉｓｔｒに負の係数であるマイナス１を乗じることで、第一逆電流判定値Ｉｒｅｆ１ａと第二逆電流判定値Ｉｒｅｆ１ｂと第三逆電流判定値Ｉｒｅｆ１ｃとを算出する。 In each of the first block 21a, the second block 21b, and the third block 21c, the determination value obtaining block 33 multiplies a predetermined determination reference value Istr by a negative coefficient of minus 1 to obtain a first reverse current determination. A value Iref1a , a second reverse current determination value Iref1b, and a third reverse current determination value Iref1c are calculated.
　第一逆電流判定値Ｉｒｅｆ１ａと第二逆電流判定値Ｉｒｅｆ１ｂと第三逆電流判定値Ｉｒｅｆ１ｃは、予め定められた判定基準値Ｉｓｔｒから決まる値である。第一逆電流判定値Ｉｒｅｆ１ａと第二逆電流判定値Ｉｒｅｆ１ｂと第三逆電流判定値Ｉｒｅｆ１ｃは、共通の値とされてもよく互いに異なる値とされてもよい。 First reverse current determination value I Ref1a and the second reverse current determination value I Ref1b the third reverse current determination value I Ref1c is a value determined from a predetermined determination reference value I str. The first reverse current determination value Iref1a , the second reverse current determination value Iref1b, and the third reverse current determination value Iref1c may be a common value or different values.
　第一逆電流判定値Ｉｒｅｆ１ａと第二逆電流判定値Ｉｒｅｆ１ｂと第三逆電流判定値Ｉｒｅｆ１ｃは、第一太陽電池ストリング＃１と第二太陽電池ストリング＃２と第三太陽電池ストリング＃３とのそれぞれの発電容量に応じた定格電流に基づいて設定されることが好ましい。具体的には、第一太陽電池ストリング＃１の定格電流が１００Ａである場合、この定格電流以下の大きさであれば逆電流を許容することができる。つまり、マイナス１００Ａまで許容することができる。 The first reverse current determination value Iref1a , the second reverse current determination value Iref1b, and the third reverse current determination value Iref1c are determined by the first solar cell string # 1, the second solar cell string # 2, and the third solar cell string # 3 is preferably set based on the rated current according to each power generation capacity. Specifically, when the rated current of the first solar cell string # 1 is 100 A, a reverse current can be permitted if the rated current is equal to or less than the rated current. That is, it is possible to tolerate up to minus 100A.
　一例として、第一逆電流判定値Ｉｒｅｆ１ａは、第一太陽電池ストリング＃１の定格電流の１倍～２倍の範囲内の任意の値に定めてもよい。第二逆電流判定値Ｉｒｅｆ１ｂと第三逆電流判定値Ｉｒｅｆ１ｃも、第一逆電流判定値Ｉｒｅｆ１ａと同様の方針で定めることができる。 As an example, the first reverse current determination value Iref1a may be set to any value within the range of 1 to 2 times the rated current of the first solar cell string # 1. The second reverse current determination value I ref1b and the third reverse current determination value I ref1c can be determined in the same manner as the first reverse current determination value I ref1a .
　「第一逆電流」は、第一直流入力部９１を通じて、第一太陽電池ストリング＃１が出力する第一直流電流とは逆方向へと流れる電流である。第一逆電流は、第一電流検出器１０ａにおいてマイナスの電流として計測される。第一逆電流の大きさが第一逆電流判定値Ｉｒｅｆ１ａを超えたことが第一電流検出器１０ａの第一検出電流値Ｉｓｔ１に基づいて検出された場合に、第一ブロック２１ａが第一短絡検出信号ＳＸ１ａを出力する。 The “first reverse current” is a current flowing through the first DC input unit 91 in a direction opposite to the first DC current output from the first solar cell string # 1. The first reverse current is measured as a negative current in the first current detector 10a. When it is detected based on the first detection current value I st1 of the first current detector 10a that the magnitude of the first reverse current exceeds the first reverse current determination value I ref1a , the first block 21a The short-circuit detection signal SX1a is output.
　実施の形態では、電流の流れる方向すなわち検出電流値の正負が考慮されることで、上記第一ブロック２１ａの検出動作が下記の具体的ロジックによって実現されている。第一ブロック２１ａにおいて、第一比較ブロック３４は、第一逆電流判定値Ｉｒｅｆ１ａと第一検出電流値Ｉｓｔ１とを比較する。第一逆電流判定値Ｉｒｅｆ１ａよりも第一検出電流値Ｉｓｔ１が小さくなった場合には、第一比較ブロック３４の出力がハイとなる。 In the embodiment, the detection operation of the first block 21a is realized by the following specific logic by considering the direction of current flow, that is, the sign of the detected current value. In the first block 21a, the first comparison block 34 compares the first reverse current determination value I ref1a with the first detected current value I st1 . When than the first reverse current determination value I Ref1a is first detected current value I st1 becomes small, the output of the first comparator block 34 becomes high.
　例えば、判定基準値Ｉｓｔｒが２００Ａに設定されることで、第一逆電流判定値Ｉｒｅｆ１ａがマイナス２００Ａに設定されているとする。第一正極負極間短絡Ｘ１が発生したときに、第一検出電流値Ｉｓｔ１が例えばマイナス３００Ａなどとなる。このとき、第一検出電流値Ｉｓｔ１が、第一逆電流判定値Ｉｒｅｆ１ａであるマイナス２００Ａを超えてマイナス側へ大きな値となっている。つまり、逆電流が流れており、且つその逆電流を計測した値の絶対値が判定基準値を超えているという事態が発生している。この場合は、第一逆電流の大きさが許容範囲を超えているので、第一比較ブロック３４の出力がハイとなる。第一比較ブロック３４のハイ出力が、すなわち第一短絡検出信号ＳＸ１ａである。 For example, it is assumed that the first reverse current determination value I ref1a is set to minus 200 A by setting the determination reference value I str to 200A. When the first positive-negative electrode short-circuit X1 occurs, the first detected current value Ist1 becomes, for example, −300 A or the like. In this case, the first detection current value I st1 has become a large value in the negative side exceeds the negative 200A is the first reverse current determination value I ref1a. That is, a situation occurs in which a reverse current is flowing, and the absolute value of the measured value of the reverse current exceeds the determination reference value. In this case, since the magnitude of the first reverse current exceeds the allowable range, the output of the first comparison block 34 becomes high. The high output of the first comparison block 34 is the first short-circuit detection signal SX1a.
　一方、第一検出電流値Ｉｓｔ１が第一逆電流判定値Ｉｒｅｆ１ａ以上である場合には、第一比較ブロック３４の出力はローとなる。例えば、第一逆電流判定値Ｉｒｅｆ１ａがマイナス２００Ａに設定されており、計測された第一検出電流値Ｉｓｔ１がマイナス１００Ａであったとする。この場合、逆電流は流れているものの、第一直流入力部９１における「マイナス方向つまり逆方向に流れる電流の大きさ」は１００Ａであり、許容範囲内であると判断される。つまり、第一検出電流値Ｉｓｔ１が第一逆電流判定値Ｉｒｅｆ１ａを超えるほどに大きく逆方向に流れる事態は、発生していない。この場合、第一比較ブロック３４の出力はローのままとなる。 On the other hand, if the first detected current value I st1 is first reverse current determination value I Ref1a above, the output of the first comparator block 34 is low. For example, it is assumed that the first reverse current determination value I ref1a is set to minus 200A and the measured first detection current value I st1 is minus 100A. In this case, although the reverse current is flowing, the “magnitude of the current flowing in the negative direction, that is, the reverse direction” in the first DC input unit 91 is 100 A, which is determined to be within the allowable range. That is, a situation where the first detection current value I st1 flows largely the opposite direction enough to exceed the first reverse current determination value I Ref1a is not generated. In this case, the output of the first comparison block 34 remains low.
　第一短絡検出信号ＳＸ１ａは、第一ブロック２１ａの出力インターフェースを通じて、スイッチオン信号Ｓ１、遮断器トリップ信号Ｓ２、Ｓ３、およびアラーム信号Ｓ４１の形態で制御部２０の外部に出力される。アラーム信号Ｓ４１は、アラーム信号Ｓ４ａの一種であり、第一直流入力部９１の側で正極負極間短絡があったことを示す。 The first short-circuit detection signal SX1a is output to the outside of the control unit 20 in the form of the switch-on signal S1, the breaker trip signals S2, S3, and the alarm signal S41 through the output interface of the first block 21a. The alarm signal S41 is a type of the alarm signal S4a, and indicates that a short circuit between the positive electrode and the negative electrode has occurred on the first DC input unit 91 side.
　第二逆電流の大きさが第二逆電流判定値Ｉｒｅｆ１ｂを超えたことが第二電流検出器１０ｂの第二検出電流値Ｉｓｔ２に基づいて検出された場合に、第二ブロック２１ｂが第二短絡検出信号ＳＸ１ｂを出力する。第二逆電流は、第二直流入力部９２を通じて、第二太陽電池ストリング＃２が出力する第二直流電流とは逆方向へと流れる電流である。第二ブロック２１ｂにおいても、上述した第一ブロック２１ａと同様の仕組みで、電流値の正負を考慮した検出動作が構築されている。 If the the magnitude of the second reverse current exceeds the second reverse current determination value I Ref1b detected based on the second detection current value I st2 of the second current detector 10b, the second block 21b is first Two short-circuit detection signals SX1b are output. The second reverse current is a current that flows through the second DC input unit 92 in a direction opposite to the second DC current output by the second solar cell string # 2. Also in the second block 21b, a detection operation taking into account the sign of the current value is constructed in the same manner as in the first block 21a.
　第二短絡検出信号ＳＸ１ｂは、第二ブロック２１ｂの出力インターフェースを通じて、スイッチオン信号Ｓ１、遮断器トリップ信号Ｓ２、Ｓ３、およびアラーム信号Ｓ４２の形態で制御部２０の外部に出力される。アラーム信号Ｓ４２は、アラーム信号Ｓ４ａの一種であり、第二直流入力部９２の側で第一正極負極間短絡Ｘ１があったことを示す。 The second short-circuit detection signal SX1b is output to the outside of the control unit 20 in the form of the switch-on signal S1, the breaker trip signals S2 and S3, and the alarm signal S42 through the output interface of the second block 21b. The alarm signal S42 is a kind of the alarm signal S4a, and indicates that the first positive-negative electrode short-circuit X1 has occurred on the side of the second DC input unit 92.
　第三逆電流の大きさが第三逆電流判定値Ｉｒｅｆ１ｃを超えたことが第三電流検出器１０ｃの第三検出電流値Ｉｓｔ３に基づいて検出された場合に、第三ブロック２１ｃが第三短絡検出信号ＳＸ１ｃを出力する。第三逆電流は、第三直流入力部９３を通じて、第三太陽電池ストリング＃３が出力する第三直流電流とは逆方向へと流れる電流である。第三ブロック２１ｃにおいても、上述した第一ブロック２１ａと同様の仕組みで、電流値の正負を考慮した検出動作が構築されている。 When it is detected based on the third detection current value Ist3 of the third current detector 10c that the magnitude of the third reverse current exceeds the third reverse current determination value Iref1c , the third block 21c performs the third block 21c. A short-circuit detection signal SX1c is output. The third reverse current is a current that flows through the third DC input unit 93 in a direction opposite to the third DC current output by the third solar cell string # 3. Also in the third block 21c, a detection operation taking into account the polarity of the current value is constructed in the same manner as in the first block 21a.
　第三短絡検出信号ＳＸ１ｃは、第三ブロック２１ｃの出力インターフェースを通じて、スイッチオン信号Ｓ１、遮断器トリップ信号Ｓ２、Ｓ３、およびアラーム信号Ｓ４３の形態で制御部２０の外部に出力される。アラーム信号Ｓ４３は、アラーム信号Ｓ４ａの一種であり、第三直流入力部９３の側で第一正極負極間短絡Ｘ１があったことを示す。 The third short-circuit detection signal SX1c is output to the outside of the control unit 20 in the form of the switch-on signal S1, the breaker trip signals S2 and S3, and the alarm signal S43 through the output interface of the third block 21c. The alarm signal S43 is a type of the alarm signal S4a, and indicates that the first positive-negative electrode short-circuit X1 has occurred on the side of the third DC input unit 93.
　以上説明した実施の形態によれば、第一直流入力部９１を介して第一太陽電池ストリング＃１からの電流を受け入れたときに、この第一太陽電池ストリング＃１の電流である第一直流電流が正しく順方向に流れているかどうかを第一短絡検出部２１が検出することができる。もし、逆方向へと流れる第一逆電流が発生しており、しかもその第一逆電流の大きさが予め定めた基準を超えている場合には、通常想定範囲を超える大きさの逆電流が第一太陽電池ストリング＃１の側へと流れている。この場合には、第一太陽電池ストリング＃１の側において第一短絡モードの第一正極負極間短絡Ｘ１が発生している可能性が高い。このような短絡検出原理は、第二直流入力部９２および第三直流入力部９３を経由して流れる電流についても同様に適用することができる。 According to the embodiment described above, when the current from the first solar cell string # 1 is received via the first DC input unit 91, the first current that is the current of the first solar cell string # 1 is received. The first short-circuit detection unit 21 can detect whether the direct current is flowing correctly in the forward direction. If the first reverse current flowing in the reverse direction has occurred and the magnitude of the first reverse current exceeds a predetermined reference, the reverse current having a magnitude exceeding the normally assumed range is usually generated. It flows toward the first solar cell string # 1. In this case, it is highly possible that the first positive-negative electrode short-circuit X1 in the first short-circuit mode has occurred on the first solar cell string # 1 side. Such a short-circuit detection principle can be similarly applied to a current flowing through the second DC input unit 92 and the third DC input unit 93.
　第一短絡検出部２１は、そのような第一短絡モードの第一正極負極間短絡Ｘ１が発生したことを示す第一短絡検出信号ＳＸ１ａを出力することができる。同様に、第一短絡検出部２１は、第二直流入力部９２および第三直流入力部９３について第一短絡モードの第一正極負極間短絡Ｘ１が発生していることを示す第二短絡検出信号ＳＸ１ｂおよび第三短絡検出信号ＳＸ１ｃを出力することができる。 (1) The first short-circuit detection unit 21 can output the first short-circuit detection signal SX1a indicating that the first positive-negative-electrode short-circuit X1 in the first short-circuit mode has occurred. Similarly, the first short-circuit detection unit 21 generates a second short-circuit detection signal indicating that the first positive-negative short-circuit X1 in the first short-circuit mode has occurred in the second DC input unit 92 and the third DC input unit 93. SX1b and the third short-circuit detection signal SX1c can be output.
　第一短絡検出信号ＳＸ１ａと第二短絡検出信号ＳＸ１ｂと第三短絡検出信号ＳＸ１ｃとが区別的に出力されるので、第一直流入力部９１と第二直流入力部９２と第三直流入力部９３のいずれで短絡が発生したのかを区別的に検出することもできる。 Since the first short-circuit detection signal SX1a, the second short-circuit detection signal SX1b, and the third short-circuit detection signal SX1c are separately output, the first DC input unit 91, the second DC input unit 92, and the third DC input unit It is also possible to discriminately detect which of 93 has caused the short circuit.
［実施の形態の第二短絡モードおよび第二短絡検出部の構成］
　図３は、実施の形態にかかる電力変換装置６の構成および第二短絡モードを示す回路図である。電力変換装置６の構成および太陽光発電システム１の構成は図１と図３とで同様であるから、構成の説明は省略する。 [Configuration of Second Short-Circuit Mode and Second Short-Circuit Detector of Embodiment]
FIG. 3 is a circuit diagram showing a configuration of the power conversion device 6 according to the embodiment and a second short-circuit mode. Since the configuration of the power conversion device 6 and the configuration of the photovoltaic power generation system 1 are the same in FIG. 1 and FIG. 3, the description of the configuration is omitted.
　図３のように、第二短絡モードすなわち第二正極負極間短絡Ｘ２は、正極直流配線６１ａと負極直流配線６１ｂとの間に発生する短絡である。第二正極負極間短絡Ｘ２が発生すると、第二正極負極間短絡Ｘ２の短絡箇所へと短絡電流Ｉｘ４が流れる。短絡電流Ｉｘ４は、第一直流入力部９１から入力される電流と、第二直流入力部９２および第三直流入力部９３から入力される電流の総和（つまり電流Ｉｘ１）と、を合計した電流である。 As shown in FIG. 3, the second short-circuit mode, that is, the second short-circuit between the positive electrode and the negative electrode X2 is a short-circuit that occurs between the positive-electrode DC wiring 61a and the negative-electrode DC wiring 61b. When the second short-circuit between the positive electrode and the negative electrode X2 occurs, the short-circuit current Ix4 flows to the short-circuit location of the second short-circuit between the positive electrode and the negative electrode X2. The short-circuit current Ix4 is a current obtained by summing the current input from the first DC input unit 91 and the sum of the currents input from the second DC input unit 92 and the third DC input unit 93 (that is, the current Ix1). It is.
　図４は、実施の形態にかかる第二短絡検出部２２を示すブロック図である。第二短絡検出部２２は、合計値算出ブロック４１と、ローパスフィルタブロック４２と、ゲインブロック４３と、第二比較ブロック４４と、を備えている。 FIG. 4 is a block diagram illustrating the second short-circuit detection unit 22 according to the embodiment. The second short-circuit detection unit 22 includes a total value calculation block 41, a low-pass filter block 42, a gain block 43, and a second comparison block 44.
　合計値算出ブロック４１は、第一検出電流値Ｉｓｔ１と第二検出電流値Ｉｓｔ２と第三検出電流値Ｉｓｔ３とを加算することで、合計電流値Ｉｓｔｓｕｍを算出する。合計電流値Ｉｓｔｓｕｍは、第二比較ブロック４４およびローパスフィルタブロック４２に入力される。 Total value calculation block 41, by adding the first detected current value I st1 and the second detected current value I st2 and a third detected current value I st3, calculates a total current value I stsum. The total current value Istsum is input to the second comparison block 44 and the low-pass filter block 42.
　ローパスフィルタブロック４２は、入力された値が予め定めた速度よりも急峻に変化した場合には、その変化をせき止めて後段の回路へ伝えないようにすることができる。ローパスフィルタブロック４２の時定数は、日射変動による緩やかな電流変化を通過させる程度の値に設定され、且つ短絡時における電流の急変を遮断できる程度の適切な値に設定される。 (4) When the input value changes more rapidly than the predetermined speed, the low-pass filter block 42 can dampen the change so as not to transmit the change to the subsequent circuit. The time constant of the low-pass filter block 42 is set to a value that allows a gradual change in current caused by fluctuations in solar radiation to pass, and is set to an appropriate value that can prevent a sudden change in current when a short circuit occurs.
　ゲインブロック４３は、入力された値に予め定められたゲイン係数Ｋを乗じる。第二短絡検出部２２では、合計電流値Ｉｓｔｓｕｍに対してローパスフィルタブロック４２によるフィルタリングが施される。次に、ローパスフィルタブロック４２を通過した値に対して、ゲインブロック４３においてゲイン係数Ｋが乗算される。 The gain block 43 multiplies the input value by a predetermined gain coefficient K. In the second short-circuit detection unit 22, the low-pass filter block 42 performs filtering on the total current value I stsum . Next, the value passed through the low-pass filter block 42 is multiplied by a gain coefficient K in a gain block 43.
　ゲイン係数は、一例として１．１～１．５の範囲内の任意の値に設定されてもよい。ゲインブロック４３は、事後的にゲイン係数Ｋを可変設定できるように構築されることが好ましい。ゲイン係数Ｋが乗算された算出値が、合計判定値Ｉｓｕｍｒｅｆとして、第二比較ブロック４４に入力される。 The gain coefficient may be set to any value within a range of 1.1 to 1.5, for example. The gain block 43 is preferably constructed so that the gain coefficient K can be variably set afterwards. The calculated value multiplied by the gain coefficient K is input to the second comparison block 44 as the total determination value I sumref .
　図５は、実施の形態にかかる第二短絡検出部２２の動作を説明するための図である。図５には、合計電流値Ｉｓｔｓｕｍの模式的なグラフが実線で図示され、これに応じた合計判定値Ｉｓｕｍｒｅｆが破線で図示されている。 FIG. 5 is a diagram for explaining the operation of the second short-circuit detection unit 22 according to the embodiment. In FIG. 5, a schematic graph of the total current value I stsum is shown by a solid line, and the corresponding total determination value I sumref is shown by a broken line.
　合計電流値Ｉｓｔｓｕｍの緩やかな変動は、日射変動を模式的に表したものである。ローパスフィルタブロック４２は日射変動による電流変化を通すので、合計電流値Ｉｓｔｓｕｍと合計判定値Ｉｓｕｍｒｅｆとが同じ傾向で緩やかに変化している。 The gradual fluctuation of the total current value I stsum schematically represents the solar radiation fluctuation. Since the low-pass filter block 42 allows the current change due to the solar radiation fluctuation, the total current value I stsum and the total determination value I sumref gradually change in the same tendency.
　図５の時刻ｔｘにおいて第二正極負極間短絡Ｘ２が発生すると、第二正極負極間短絡Ｘ２に短絡電流が流れる。この短絡電流に起因して太陽電池ストリングス＃１～＃３の側から流れ込む電流が増加するので、第一電流検出器１０ａ～第三電流検出器１０ｃそれぞれで計測される電流値が増加する。結果的に、図５に示すように、時刻ｔｘにおいて合計電流値Ｉｓｔｓｕｍが急峻に増加する。 When the second short-circuit between the positive electrode and the negative electrode occurs at the time tx in FIG. 5, a short-circuit current flows through the second short-circuit between the positive electrode and the negative electrode X2. Since the current flowing from the solar cell strings # 1 to # 3 increases due to the short-circuit current, the current value measured by each of the first current detector 10a to the third current detector 10c increases. As a result, as shown in FIG. 5, the total current value Istsum sharply increases at time tx.
　ローパスフィルタブロック４２は、時刻ｔｘにおける合計電流値Ｉｓｔｓｕｍの急峻な変化をせき止める。したがって、時刻ｔｘにおいても、合計判定値Ｉｓｕｍｒｅｆは短絡発生直前の値を保持する。合計判定値Ｉｓｕｍｒｅｆが一定であるのに対して合計電流値Ｉｓｔｓｕｍが急峻に増加するので、符号Ｑに示したポイントで合計電流値Ｉｓｔｓｕｍが合計判定値Ｉｓｕｍｒｅｆを超えて増加する。 The low-pass filter block 42 blocks a steep change in the total current value I stsum at the time tx. Therefore, even at time tx, the total determination value I sumref holds the value immediately before the occurrence of the short circuit. Since the total current value I Stsum total determination value I Sumref Whereas constant increases sharply, points total current value I Stsum indicated by reference numeral Q increases beyond the total judgment value I sumref.
　第二比較ブロック４４は、合計電流値Ｉｓｔｓｕｍと合計判定値Ｉｓｕｍｒｅｆとを比較する。時刻ｔｘよりも手前の合計電流値Ｉｓｔｓｕｍが合計判定値Ｉｓｕｍｒｅｆ以下である期間には、第一比較ブロック３４の出力はローとなる。しかしながら、上記図５のポイントＱにおいて合計電流値Ｉｓｔｓｕｍが合計判定値Ｉｓｕｍｒｅｆよりも大きくなった場合には、第二比較ブロック４４の出力がハイとなる。つまり、合計電流値Ｉｓｔｓｕｍが、合計判定値Ｉｓｕｍｒｅｆをプラス側に超えている。第二比較ブロック４４のハイ出力が、すなわち短絡検出信号ＳＸ２である。 The second comparison block 44 compares the total current value Istsum with the total determination value Isumref . During a period in which the total current value I stsum before the time tx is equal to or less than the total determination value I sumref , the output of the first comparison block 34 is low. However, when the total current value I stsum becomes larger than the total determination value I sumref at the point Q in FIG. 5 described above, the output of the second comparison block 44 becomes high. That is, the total current value I sumsum exceeds the total determination value I sumref to the plus side. The high output of the second comparison block 44 is the short-circuit detection signal SX2.
　以上説明した実施の形態によれば、第一直流入力部９１～第三直流入力部９３を介して太陽電池ストリングス＃１～＃３それぞれからの電流を受け入れたときに、合計電流値Ｉｓｔｓｕｍの大きさが適正であるかを第二短絡検出部２２が判定することができる。もし、合計電流の大きさが予め定めた基準を超えている場合には、本来の電流よりも大きな電流が電力変換回路１２の側へと流れている。この場合には、電力変換回路１２の前段において第二短絡モードの第二正極負極間短絡Ｘ２が発生している可能性が高い。そこで、第二短絡検出部２２はそのような第二短絡モードの第二正極負極間短絡Ｘ２が発生したことを示す短絡検出信号ＳＸ２を出力することができる。 According to the embodiment described above, when the currents from the solar cell strings # 1 to # 3 are received via the first DC input unit 91 to the third DC input unit 93, respectively, the total current value I stimum The second short-circuit detection unit 22 can determine whether or not the size is appropriate. If the magnitude of the total current exceeds a predetermined reference, a current larger than the original current flows to the power conversion circuit 12 side. In this case, there is a high possibility that the second short-circuit between the positive electrode and the negative electrode in the second short-circuit mode X2 has occurred in the previous stage of the power conversion circuit 12. Therefore, the second short-circuit detection unit 22 can output the short-circuit detection signal SX2 indicating that the second short-circuit between the positive electrode and the negative electrode X2 in the second short-circuit mode has occurred.
　また、ローパスフィルタブロック４２およびゲインブロック４３を備えることで、下記の利点もある。電力システムごとに太陽電池ストリングス＃１～＃３の数および太陽電池ストリングスごとの電流値が異なる。その結果、電力システムが異なれば、合計電流を判定するための適切な合計判定値Ｉｓｕｍｒｅｆも異なる。この点、実施の形態によれば、合計電流値Ｉｓｔｓｕｍに対してローパスフィルタブロック４２およびゲインブロック４３による演算が施されることで、適切な合計判定値Ｉｓｕｍｒｅｆが算出される。その結果、システムごとに、合計判定値Ｉｓｕｍｒｅｆを個別に設定し直さなくともよい利点がある。 The provision of the low-pass filter block 42 and the gain block 43 also has the following advantages. The number of solar cell strings # 1 to # 3 and the current value for each solar cell string differ for each power system. As a result, different power systems also have different appropriate sum determination values I sumref for determining the total current. In this regard, according to the embodiment, an appropriate total determination value I sumref is calculated by performing an operation on the total current value I stsum by the low-pass filter block 42 and the gain block 43. As a result, there is an advantage that it is not necessary to individually set the total determination value I sumref for each system.
　また、実施の形態によれば、ゲイン係数Ｋが１．１～１．５なので、実際に入力される合計電流値Ｉｓｔｓｕｍの１．１～１．５倍の値を合計判定値Ｉｓｕｍｒｅｆに設定することができる。その結果、正極負極間短絡時に流れる電流が小さくとも、第二正極負極間短絡Ｘ２を迅速かつ高精度に検出することができる。ゲイン係数Ｋは１よりも大きな任意の値に設定することができる。 In addition, according to the embodiment, since the gain coefficient K is 1.1 to 1.5, a value 1.1 to 1.5 times the actually input total current value I stsum is used as the total determination value I sumref . Can be set. As a result, even if the current flowing at the time of the short circuit between the positive electrode and the negative electrode is small, the second short circuit X2 between the positive electrode and the negative electrode can be detected quickly and accurately. Gain coefficient K can be set to any value greater than one.
　また、実施の形態では、スイッチＳＷが、第二短絡検出部２２の出力するスイッチオン信号Ｓ１に応答して導通する。第二短絡モードの第二正極負極間短絡Ｘ２の発生時に意図的に短絡電流を流すための経路を作り出すことができるので、発生した短絡箇所に流れる電流を低減することができる。よって、第一短絡モードと第二短絡モードの両方に対して保護機能が万全となる。 In the embodiment, the switch SW is turned on in response to the switch-on signal S1 output from the second short-circuit detection unit 22. When a second short-circuit between the positive electrode and the negative electrode in the second short-circuit mode X2 occurs, a path for flowing a short-circuit current can be intentionally created, so that the current flowing to the generated short-circuit portion can be reduced. Therefore, the protection function is perfect for both the first short-circuit mode and the second short-circuit mode.
　また、実施の形態では、制御部２０が、第一短絡検出部２１と第二短絡検出部２２の少なくとも一方が短絡を検出したときに直流側遮断器１１と交流側遮断器１５の少なくとも一方をトリップするように構築されている。したがって、さらに保護機能を万全にすることができる。 Further, in the embodiment, when at least one of the first short-circuit detection unit 21 and the second short-circuit detection unit 22 detects a short circuit, the control unit 20 switches at least one of the DC-side circuit breaker 11 and the AC-side circuit breaker 15. It is built to trip. Therefore, the protection function can be further improved.
　実施の形態にかかる制御部２０は、第一短絡検出部２１と第二短絡検出部２２の両方を備えている。したがって、第一短絡モードの第一正極負極間短絡Ｘ１と第二短絡モードの第二正極負極間短絡Ｘ２とを区別的に検出することができる。実施の形態では、第一正極負極間短絡Ｘ１に応じてアラーム信号Ｓ４ａ（より詳細にはＳ４１、Ｓ４２、Ｓ４３）が出力され、第二正極負極間短絡Ｘ２に応じてアラーム信号Ｓ４ｂが出力される。これにより、単なる短絡検出だけではなく短絡の具体的な場所を外部に報知することもできる。 The control unit 20 according to the embodiment includes both the first short-circuit detection unit 21 and the second short-circuit detection unit 22. Therefore, the first short-circuit between the positive electrode and the negative electrode X1 in the first short-circuit mode and the second short-circuit between the positive electrode and the negative electrode X2 in the second short-circuit mode can be detected separately. In the embodiment, an alarm signal S4a (more specifically, S41, S42, S43) is output according to the first positive-negative short-circuit X1, and an alarm signal S4b is output according to the second positive-negative short-circuit X2. . As a result, not only the detection of a short circuit but also the specific location of the short circuit can be notified to the outside.
［実施の形態の変形例］
　なお、図４のローパスフィルタブロック４２に代えて、バンドパスフィルタブロックが用いられてもよい。このバンドパスフィルタブロックに、このローパスフィルタブロック４２と同様に高周波数域の信号をせき止めるフィルタ機能を持たせればよい。 [Modification of Embodiment]
Note that a band-pass filter block may be used instead of the low-pass filter block 42 in FIG. This band-pass filter block may be provided with a filter function for blocking a signal in a high-frequency range similarly to the low-pass filter block 42.
　なお、ローパスフィルタブロック４２とゲインブロック４３の順番は、図４とは逆の順番つまりゲインブロック４３が前段であっても良い。 Note that the order of the low-pass filter block 42 and the gain block 43 may be opposite to that in FIG. 4, that is, the gain block 43 may be in the preceding stage.
　図６は、実施の形態の変形例にかかる第二短絡検出部２２を示すブロック図である。判定値設定部１４３は、合計判定値Ｉｓｕｍｒｅｆを書き換え可能に記憶している。図６の変形例では、合計判定値Ｉｓｕｍｒｅｆが合計電流値Ｉｓｔｓｕｍとは独立に定められた固定値または可変設定値とされる。 FIG. 6 is a block diagram illustrating a second short-circuit detection unit 22 according to a modification of the embodiment. The determination value setting unit 143 stores the total determination value I sumref in a rewritable manner. In the modified example of FIG. 6, the total determination value I sumref is a fixed value or a variable set value determined independently of the total current value I stsum .
　第一短絡検出部２１と第二短絡検出部２２のうち片方のみを備えた電力変換装置６が提供されても良い。 (4) The power conversion device 6 including only one of the first short-circuit detection unit 21 and the second short-circuit detection unit 22 may be provided.
　なお、実施の形態では、３つの太陽電池ストリング＃１～＃３を備えた太陽光発電システム１が提供されている。しかしながら、太陽電池ストリングの個数は３つに限られない。太陽電池ストリングの個数は１つでもよく、２つでもよく、４つ以上でもよい。接続される太陽電池ストリングの個数に応じて、上述した各種判定値を調整すれば良い。 In the embodiment, a solar power generation system 1 including three solar cell strings # 1 to # 3 is provided. However, the number of solar cell strings is not limited to three. The number of solar cell strings may be one, two, or four or more. The above-described various determination values may be adjusted according to the number of connected solar cell strings.
　図７は、実施の形態にかかる制御部２０の構成例である。図７はこの発明の実施の形態における制御部２０に適用可能なハードウェア構成図である。図７に示されるように、制御部２０の各機能は、処理回路５０により実現し得る。処理回路５０は、プロセッサ５１とメモリ５２とを備える。 FIG. 7 is a configuration example of the control unit 20 according to the embodiment. FIG. 7 is a hardware configuration diagram applicable to the control unit 20 according to the embodiment of the present invention. As shown in FIG. 7, each function of the control unit 20 can be realized by the processing circuit 50. The processing circuit 50 includes a processor 51 and a memory 52.
　例えば、プロセッサ５１は、中央処理装置、処理装置、マイクロプロセッサ、マイクロコンピュータ、プロセッサ又はＤＳＰなどのＣＰＵ（Ｃｅｎｔｒａｌ　Ｐｒｏｃｅｓｓｉｎｇ　Ｕｎｉｔ）である。例えば、メモリ５２は、ＲＡＭ、ＲＯＭ、フラッシュメモリ、ＥＰＲＯＭ、ＥＥＰＲＯＭ等の不揮発性または揮発性の半導体メモリ、磁気ディスク、フレキシブルディスク、光ディスク、コンパクトディスク、ミニディスク、ＤＶＤである。処理回路５０において、メモリ５２に格納されたプログラムがプロセッサ５１によって実行される。 For example, the processor 51 is a CPU (Central Processing Unit) such as a central processing unit, a processing unit, a microprocessor, a microcomputer, a processor, or a DSP. For example, the memory 52 is a non-volatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, an EEPROM, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, and a DVD. In the processing circuit 50, a program stored in the memory 52 is executed by the processor 51.
　なお、実施の形態では太陽光発電システム１が提供されているが、電力変換装置６は太陽光発電用途のみに限られるものではない。電力変換装置６に対して太陽電池以外の定電流電源が接続されても良い。 In addition, although the photovoltaic power generation system 1 is provided in the embodiment, the power conversion device 6 is not limited to only the photovoltaic power generation use. A constant current power source other than a solar cell may be connected to the power converter 6.
１　太陽光発電システム、＃１　第一太陽電池ストリング、＃２　第二太陽電池ストリング、＃３　第三太陽電池ストリング、２ａ、２ｂ、２ｃ　太陽電池パネル、４ａ　第一接続箱、４ｂ　第二接続箱、４ｃ　第三接続箱、６　電力変換装置、７　ヒューズ、９ａ　正極端子、９ｂ　負極端子、１０ａ　第一電流検出器、１０ｂ　第二電流検出器、１０ｃ　第三電流検出器、１１　直流側遮断器、１２　電力変換回路、１２ａ　正極入力端、１２ｂ　負極入力端、１３　直流平滑コンデンサ、１４　交流フィルタ回路、１５　交流側遮断器、１６　変圧器、１７　電力系統、２０　制御部、２１　第一短絡検出部、２１ａ　第一ブロック、２１ｂ　第二ブロック、２１ｃ　第三ブロック、２２　第二短絡検出部、３３　判定値取得ブロック、３４　第一比較ブロック、４１　合計値算出ブロック、４２　ローパスフィルタブロック、４３　ゲインブロック、４４　第二比較ブロック、５０　処理回路、５１　プロセッサ、５２　メモリ、６１ａ　正極直流配線、６１ｂ　負極直流配線、９１　第一直流入力部、９２　第二直流入力部、９３　第三直流入力部、１４３　判定値設定部、Ｉｒｅｆ１ａ　第一逆電流判定値、Ｉｒｅｆ１ｂ　第二逆電流判定値、Ｉｒｅｆ１ｃ　第三逆電流判定値、Ｉｓｔ１　第一検出電流値、Ｉｓｔ２　第二検出電流値、Ｉｓｔ３　第三検出電流値、Ｉｓｔｒ　判定基準値、Ｉｓｔｓｕｍ　合計電流値、Ｉｓｕｍｒｅｆ　合計判定値、Ｓ１　スイッチオン信号、Ｓ２、Ｓ３　遮断器トリップ信号、Ｓ４１、Ｓ４２、Ｓ４３、Ｓ４ａ　アラーム信号、Ｓ４ｂ　アラーム信号、ＳＷ　スイッチ、ＳＸ１ａ　第一短絡検出信号、ＳＸ１ｂ　第二短絡検出信号、ＳＸ１ｃ　第三短絡検出信号、ＳＸ２　短絡検出信号、Ｘ１　第一正極負極間短絡、Ｘ２　第二正極負極間短絡 Reference Signs List 1 solar power generation system, # 1 first solar cell string, # 2 second solar cell string, # 3 third solar cell string, 2a, 2b, 2c solar panel, 4a first connection box, 4b second connection box 4c third connection box, 6 power converter, 7 fuse, 9a positive terminal, 9b negative terminal, 10a first current detector, 10b second current detector, 10c third current detector, 11 DC circuit breaker, Reference Signs List 12 power conversion circuit, 12a positive input terminal, 12b negative input terminal, 13 DC smoothing capacitor, 14 AC filter circuit, 15 AC circuit breaker, 16 transformer, 17 power system, 20 control unit, 21 first short circuit detection unit, 21a first block, 21b second block, 21c third block, 22 second short circuit detector, 33 judgment value acquisition block, 34 first comparison block, 41 total value calculation block Block, 42 low-pass filter block, 43 gain block, 44 second comparison block, 50 processing circuit, 51 processor, 52 memory, 61a positive DC wiring, 61b negative DC wiring, 91 first DC input section, 92 second DC Input unit, 93 third DC input unit, 143 judgment value setting unit, I ref1a first reverse current judgment value, I ref1b second reverse current judgment value, I ref1c third reverse current judgment value, I st1 first detection current value , I st2 second detected current value, I st3 third detected current value, I str determination reference value, I stsum total current value, I sumref total judgment value, S1 switch-on signal, S2, S3 breaker trip signal, S41, S42, S43, S4a alarm signal, S4b alarm signal, SW switch, SX1a first short-circuit detection signal, SX1b second short-circuit detection Signal, SX1c third short-circuit detection signal, SX2 short circuit detection signal, a short circuit between X1 first positive electrode a negative electrode, a short circuit between X2 second positive negative

Claims (6)

  1. 　第一直流電流を受け入れ可能に構築された第一直流入力部と、
    　前記第一直流入力部から入力された前記第一直流電流を変換することで交流電流を出力する電力変換回路と、
    　前記第一直流入力部に設けられた第一電流検出器と、
    　前記第一直流入力部を通じて前記第一直流電流と逆方向へと流れる第一逆電流の大きさが第一判定値を超えたことが前記第一電流検出器の出力に基づいて検出された場合に、第一短絡検出信号を出力するように構築された短絡検出部と、
    　を備える電力変換装置。     A first DC input unit constructed to accept the first DC current,
    A power conversion circuit that outputs an AC current by converting the first DC current input from the first DC input unit,
    A first current detector provided in the first DC input unit,
    The magnitude of the first reverse current flowing in a direction opposite to the first direct current through the first direct current input unit was detected based on the output of the first current detector that the magnitude of the first reverse current exceeded a first determination value. In the case, a short-circuit detection unit configured to output a first short-circuit detection signal,
    A power conversion device comprising:
  2. 　第二直流電流を受け入れ可能な第二直流入力部と、
    　前記第二直流入力部に設けられた第二電流検出器と、
    　をさらに備え、
    　前記短絡検出部は、前記第二直流入力部を通じて前記第二直流電流と逆方向へと流れる第二逆電流の大きさが第二判定値を超えたことが前記第二電流検出器の出力に基づいて検出された場合に、第二短絡検出信号を出力するように構築された請求項１に記載の電力変換装置。     A second DC input unit capable of receiving a second DC current;
    A second current detector provided in the second DC input unit,
    Further comprising
    The short-circuit detection unit, the output of the second current detector that the magnitude of the second reverse current flowing in the opposite direction to the second DC current through the second DC input unit exceeds the second determination value The power conversion device according to claim 1, wherein the power conversion device is configured to output a second short-circuit detection signal when the power conversion device detects the second short-circuit detection signal.
  3. 　前記電力変換回路は、
    　前記第一直流入力部の正極に接続された正極入力端と、
    　前記第一直流入力部の負極に接続された負極入力端と、
    　を有し、
    　一端が前記正極入力端に接続され他端が前記負極入力端に接続され、前記短絡検出部が出力した前記第一短絡検出信号に応答して前記正極入力端と前記負極入力端とを導通させるスイッチを、
    　さらに備える請求項１に記載の電力変換装置。     The power conversion circuit,
    A positive input terminal connected to the positive electrode of the first DC input unit,
    A negative input terminal connected to the negative electrode of the first DC input unit;
    Has,
    One end is connected to the positive input terminal and the other end is connected to the negative input terminal, and the positive input terminal and the negative input terminal are electrically connected in response to the first short detection signal output by the short detection unit. Switch
    The power converter according to claim 1, further comprising:
  4. 　第一直流電流を受け入れ可能に構築された第一直流入力部と、
    　第二直流電流を受け入れ可能に構築された第二直流入力部と、
    　前記第一直流入力部および前記第二直流入力部のそれぞれの正極に接続された正極入力端と、前記第一直流入力部および前記第二直流入力部のそれぞれの負極に接続された負極入力端と、を有する電力変換回路と、
    　前記第一直流入力部に設けられた第一電流検出器と、
    　前記第二直流入力部に設けられた第二電流検出器と、
    　前記第一電流検出器で検出した電流値と前記第二電流検出器で検出した電流値とを合計した合計電流値が判定値を超えた場合には、短絡検出信号を出力するように構築された短絡検出部と、
    　を備える電力変換装置。     A first DC input unit constructed to accept the first DC current,
    A second DC input unit configured to accept a second DC current,
    A positive input terminal connected to each positive electrode of the first DC input unit and the second DC input unit, and a negative electrode connected to each negative electrode of the first DC input unit and the second DC input unit A power conversion circuit having an input end;
    A first current detector provided in the first DC input unit,
    A second current detector provided in the second DC input unit,
    If the total current value obtained by summing the current value detected by the first current detector and the current value detected by the second current detector exceeds the determination value, a short-circuit detection signal is output. Short-circuit detection unit,
    A power conversion device comprising:
  5. 　前記短絡検出部は、
    　予め定めた速度よりも急峻に変化する信号をせき止めるフィルタ部と、
    　入力された値に予め定められたゲイン係数を乗じるゲイン部と、
    　を含み、
    　前記短絡検出部は、前記フィルタ部によるフィルタリングおよび前記ゲイン部による前記ゲイン係数の乗算を前記合計電流値に対して施した値を前記判定値とするように構築された請求項４に記載の電力変換装置。     The short-circuit detection unit,
    A filter section for damping a signal that changes more rapidly than a predetermined speed,
    A gain unit for multiplying the input value by a predetermined gain coefficient,
    Including
    5. The electric power according to claim 4, wherein the short-circuit detection unit is configured to set a value obtained by performing filtering by the filter unit and multiplication of the gain coefficient by the gain unit on the total current value as the determination value. 6. Conversion device.
  6. 　一端が前記正極入力端に接続され他端が前記負極入力端に接続され、前記短絡検出部が出力した前記短絡検出信号に応答して前記正極入力端と前記負極入力端とを導通させるスイッチを、さらに備える請求項４に記載の電力変換装置。 One end is connected to the positive input terminal, the other end is connected to the negative input terminal, and a switch that conducts the positive input terminal and the negative input terminal in response to the short-circuit detection signal output by the short-circuit detection unit. The power converter according to claim 4, further comprising:
PCT/JP2018/036059 2018-09-27 2018-09-27 Power conversion device WO2020065857A1 (en)

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TWI737514B (en) * 2020-10-13 2021-08-21 台達電子工業股份有限公司 Boost conversion module with protection circuit

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JP2012019646A (en) * 2010-07-09 2012-01-26 Daihen Corp Control device of power converter, and system interconnection inverter system using the control device
WO2012046331A1 (en) * 2010-10-07 2012-04-12 東芝三菱電機産業システム株式会社 Failure detecting apparatus
JP2012253848A (en) * 2011-05-31 2012-12-20 Toshiba Corp Photovoltaic power generation system

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JP2012019646A (en) * 2010-07-09 2012-01-26 Daihen Corp Control device of power converter, and system interconnection inverter system using the control device
WO2012046331A1 (en) * 2010-10-07 2012-04-12 東芝三菱電機産業システム株式会社 Failure detecting apparatus
JP2012253848A (en) * 2011-05-31 2012-12-20 Toshiba Corp Photovoltaic power generation system

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TWI737514B (en) * 2020-10-13 2021-08-21 台達電子工業股份有限公司 Boost conversion module with protection circuit

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