JP6103197B2 - Inverter - Google Patents

Description

  The present invention relates to a power conditioner used for a photovoltaic power generation system or the like.

  This type of conventional power conditioner is provided with a terminal block in which a plurality of connection terminals for connecting various input / output wirings are arranged in a row. Each connection terminal of this terminal block includes a DC 2-wire terminal for generating power input, an AC 3-wire terminal for outputting the converted power to the power system, and an AC 2-wire terminal connected to a stand-alone power outlet. And as a connection terminal such as a ground terminal.

  If the connection to the connection terminal of such terminal block is wrong during construction, it may cause abnormal operation when starting the inverter or damage to internal circuit parts. It was necessary to make a stand configuration.

  As a technique for avoiding such a connection error to the terminal block, for example, there is a technique disclosed in Patent Document 1 below. In this prior art, a cover body that covers the input terminal and a cover body that covers the output terminal are provided separately so that only the input terminal can be connected when connecting the input side, and only the output terminal can be connected when connecting the output side. By connecting either the terminal or the output terminal one by one, it is difficult for the operator to make a wrong connection.

Japanese Utility Model Publication No. 7-11765

  However, the structure of the conventional terminal block is cumbersome because it is necessary to cover all the input side and output side with a cover body and to open the cover body one by one when performing the wiring work.

  On the other hand, the input of the inverter is a DC 2-wire terminal from the power generation unit, and the output is an AC 3-wire terminal. Since the number of these input terminals and output terminals is different, input is performed during wiring work. If the terminal for output and the terminal for output are visually distinguished, it is considered that there is almost no erroneous connection.

  Accordingly, an object of the present invention is to provide a power conditioner that can prevent erroneous connection with a simple configuration.

  In order to achieve the above object, the present invention takes the following technical means.

  That is, the power conditioner of the present invention has at least six connection terminals arranged in a left and right line, and two adjacent ones of the connection terminals are DC two-wire terminals, excluding the DC two-wire terminals. In the power conditioner in which three adjacent ones of the connection terminals are AC three-wire terminals, at least one covered with a removable cover between the DC two-wire terminal and the AC three-wire terminal. Connection terminals are arranged, and the number of connection terminals on the left side of the connection terminals covered with the cover is different from the number of connection terminals on the right side (Claim 1).

  According to the power conditioner of the present invention, the direct current 2-wire terminal and the alternating current 3-wire terminal are arranged apart from each other, and the connection terminals between them are covered with the cover, so that the plurality of connection terminals are left and right. By dividing into two groups and the number of connecting terminals in these groups are different, it is possible to increase the attention of construction workers, and the DC 2-wire terminals and AC 3-wire terminals are misconnected. Can be prevented. Moreover, the connection work to the connection terminal covered with the cover can be performed by removing the cover after performing the connection work to the DC 2-wire terminal and the AC 3-wire terminal. The cover may be a hard cover made of plastic or metal, but may be a simple one such as an adhesive tape.

Further, in the power conditioner of the present invention, the DC two-line terminal is an input terminal for inputting the generated power of the DC output from the power generation unit, the terminal for the alternating three-wire is communicated to the power system Oh Ru output terminals for outputting generated power is converted into AC power to the system to the power grid (claim 1). According to this, it is possible to prevent the DC 2-wire input terminal from being connected to the electric power system, and circuit components such as a driver IC (semiconductor switching element) due to the supply of AC power to the input side. Can be prevented from being damaged.

Moreover, said the connection between terminals of the DC 2-wire terminal can be provided with a diode having an anode connected to the positive electrode terminal side cathode connected to and negative terminal side (claim 2). According to this, when the positive electrode and the negative electrode of the DC 2-wire terminal are wired in reverse, the diode is short-circuited, and the voltage between the DC 2-wire terminals is fixed to the forward voltage of the diode. Further, an excessive reverse voltage is prevented from being applied to other elements, thereby preventing damage.

Furthermore, it can be provided with a notification means for performing a predetermined notification when a reverse current flows through the DC 2-wire terminal (claim 3 ). According to this, when the positive and negative electrodes of the DC 2-wire terminal are wired in reverse, or when the AC wiring is connected to the DC 2-wire terminal, etc., when checking the operation after the wiring work By notifying by the occurrence of the reverse current, the operator can be made aware that the wiring is incorrect. The detection of reverse current can be detected by an input current sensor arranged on the input side of the diode, and a current sensor that can detect a current value in both positive and negative directions in order to detect current during normal operation. Is preferably used.

Also, the a number of covered connection terminal in the cover is two, the two connecting terminals may be a AC 2-wire terminals for autonomous power generation output (claim 4). According to this, by covering only the AC two-wire terminal for independent power generation output, which is an auxiliary function, with the cover, wiring connection for the main function can be easily and quickly performed without operating the cover.

Further, a ground wire terminal can be further provided as a connection terminal. Furthermore, the DC two-line terminal, the AC two-wire terminals, it is preferable to arrange the order of the AC three-wire terminals and terminal said ground wire (claim 5). According to this, since the two connection terminals and the four connection terminals are exposed on the left and right sides of the cover, there is almost no misconnection between the three AC lines and the two connection terminals. Even if the connection is mistakenly connected to the AC three-wire terminal first, there is no three consecutive empty connection terminals when trying to connect the AC three-wire, so that the erroneous connection can be noticed. Also, even if an incorrect connection occurs between the four connection terminals of the ground wire terminal and the AC 3 wire terminal, normal operation does not occur, but there is no major problem in the circuit configuration, and the operator can review the connection by not operating normally. Just connect correctly.

  As described above, according to the power conditioner according to claim 1 of the present application, the DC 2-wire terminal and the AC 3-wire terminal are arranged apart from each other, and the connection terminal between them is covered with the cover. By dividing the plurality of connection terminals into two groups on the left and right sides, and the number of connection terminals in these groups is different, it is possible to increase the attention of construction workers, and the DC 2-wire terminals and AC It is possible to prevent erroneous connection between the 3-wire terminals. Moreover, the connection work to the connection terminal covered with the cover can be performed by removing the cover after performing the connection work to the DC 2-wire terminal and the AC 3-wire terminal.

Further, according to the power conditioner according to claim 1 of the present application, it is possible to prevent the DC 2-wire input terminal from being connected to the power system, and the driver is caused by the supply of AC power to the input side. It is possible to prevent damage to circuit components such as an IC (semiconductor switching element).

1 is a schematic circuit configuration diagram of a power conditioner according to a first embodiment of the present invention. It is a front view of the terminal block of the same inverter. It is a front view of the state which provided the cover in the terminal block. It is a schematic circuit block diagram of the power conditioner which concerns on the 2nd Embodiment of this invention. It is a schematic circuit block diagram of the power conditioner which concerns on the 3rd Embodiment of this invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a power conditioner according to a first embodiment of the present invention. The power conditioner is used in a solar power generation system, a fuel cell power generation system, and the like, and is a direct current supplied from a DC power source as a power generation unit. The power is converted into AC power that is connected to single-phase three-wire commercial grid power and output to the commercial power grid.

  The power conditioner of the present embodiment includes a DC link unit 1 configured by a DC link capacitor, and a boost chopper that boosts DC power supplied from a DC power source to a predetermined voltage (for example, 350 V) and outputs it to the DC link unit 1. A DC / DC converter 2 composed of a circuit, and a voltage-type bridge inverter 3 (DC / AC inverter) for converting DC power supplied from the DC link unit 1 into AC power linked to system power and outputting it to the system side ).

  The step-up chopper circuit that constitutes the converter 2 includes a step-up reactor 21, a step-up rectifier 22 that prevents backflow of current during step-up operation to the step-up reactor 21, and a driver such as an IGBT that controls the stored energy of the step-up reactor 21. 23, and the cathode side of the rectifier 22 is connected to the positive electrode side of the DC link capacitor 1.

  The inverter 3 is a full-bridge type voltage-type bridge inverter, and is configured by connecting four IGBT 31 and other drivers 31 in an H-bridge type, and connecting a feedback diode 32 to each switching element 31 in parallel. A connected reactor 33 is provided on the side. The inverter 3 controls the output current by performing so-called current mode control (current control of the voltage source inverter). When power is output to the system, the DC power from the DC link unit 1 is controlled by PWM control or PAM. It is converted into AC power by control and output to the grid.

  Semiconductor elements such as the drivers 23 and 31 and the diodes 22 and 32 of the converter 2 and the inverter 3 are incorporated in an IC chip such as an IGBT power module.

  On the input side of the converter 2, a noise filter 4 that reduces harmonic noise generated in the converter 2 and the inverter 3 is provided.

  A disconnection protection relay 5 and an output filter circuit 6 are provided on the output side of the inverter 3, and a single-phase three-wire commercial power system is connected to the output side of the output filter circuit 6. A stand-alone power generation relay 7 is provided in parallel with the disconnection protection relay 5, and a stand-alone power generation outlet is connected to the output side of the relay 7.

  The power conditioner has a built-in control unit (not shown) for controlling the converter 2, the inverter 3, the disconnection protection relay 5, and the self-sustaining power generation relay 7, and the control unit is a DC link unit 1. It operates by the electric power supplied from.

  Further, the power conditioner includes a terminal block 8 as shown in FIG. 2, and eight connection terminals for power input / output are provided in the left and right rows in the lower stage of the terminal block 8. In the upper stage, eight connection terminals for connection to the substrate are provided in a left and right line. The upper eight connection terminals are respectively connected to the lower eight terminals, and are also connected in advance to the board on which the converter 2 and the inverter 3 are mounted when the power conditioner is shipped.

  The eight connection terminals for power input / output are, in order from the left end, DC two-wire input terminals (P, N) for connecting a DC power source serving as a power generation unit, and AC two-wire output terminals for connection to an independent outlet ( L1, L2), an AC three-wire output terminal (U, O, W) for connection to a single-phase three-wire commercial power system, and a ground terminal (E) for ground connection. The DC two-wire input terminals (P, N) are connected to the input side of the input filter circuit 4, and the AC two-wire output terminals (L1, L2) are connected to the output side of the self-sustaining power generation relay 7, and the AC 3 The line output terminals (U, O, W) are connected to the output side of the output filter circuit 6. The order of the positive terminal (P) and the negative terminal (N) of the DC two-wire input terminal (P, N) is not particularly limited, but in the illustrated example, the positive terminal (P) is disposed at the leftmost end. . The order of the U-phase connection terminal (U), the W-phase connection terminal (W) and the neutral wire connection terminal (O) of the AC three-wire output terminal (U, O, W) is not particularly limited. The wire connection terminal (O) is arranged in the middle, and the W-phase connection terminal (W) is arranged on the right end side with respect to the U-phase connection terminal (U).

  As shown in FIG. 3, the AC two-wire output terminals (L1, L2) of the terminal block 8 are made of a cover made of adhesive tape or the like that covers the output terminals (L1, L2) when the power conditioner is shipped. 9 is affixed, and when the cover 9 is affixed, connection to these output terminals (L1, L2) cannot be made. The cover 9 is not removed until the wiring is connected to a self-supporting outlet. In addition, when not providing a self-supporting outlet, the cover 9 can be left attached.

  In addition, when the DC power source connection to the DC 2-wire input terminal (P, N) is wrongly wired between the positive side and the negative side, the reverse electromotive force is short-circuited to the negative side of the DC power source and the converter 2 is connected. In order to protect the circuit components, a short-circuit diode 10 is provided between the DC two-wire input terminals (P, N), the cathode of the diode 10 is connected to the positive terminal (P) side, and the anode is It is connected to the negative terminal (N) side.

  According to the power conditioner of the present embodiment, the connection terminals are arranged in two groups and four groups by hiding the AC two-wire output terminals (L1, L2) for connecting the independent outlets with the cover 9 at the time of shipment. . Therefore, when connecting AC 3 wires to be connected to the system, it is necessary to straddle the independent terminals (L1, L2) when trying to connect the AC 3 wires to the DC 2-wire input terminals (P, N). As a result, the installer can immediately realize that the connection is wrong. Although there is a possibility of incorrect connection between the four connection terminals of the AC three-wire output terminal (U, O, W) and the grounding terminal (E), even if an incorrect connection is made between them. Since it does not operate due to an AC voltage error, there is no problem, and it can be immediately recognized that an error has occurred due to the occurrence of such an error.

  When a DC power source is connected to the DC two-wire input terminals (P, N) in positive and negative directions, the short-circuit diode 10 has a cathode side on the negative side of the power source and an anode side on the positive side of the power source. A current flows through the path 10, and the voltage between the DC two-wire input terminals (P, N) is clamped to the forward voltage of the diode 10, so that the circuit components constituting the input filter circuit 4 and the converter 2 However, since only the forward voltage is applied, these circuit components can be prevented from being damaged. Note that the rating of the short-circuit diode 10 depends on the output of a solar panel or the like constituting the DC power supply to be connected, the reverse breakdown voltage is higher than the open voltage, and the forward current is higher than the short-circuit current. Keep the heat generation below the rated temperature so that it will not be damaged even if current continues to flow. For example, if the open voltage of the solar panel is 380V and the short-circuit current is 20A, the short-circuit diode 10 has a reverse withstand voltage of 400V and a forward current of 30A, and the forward voltage is about 2.0V. If so, take measures such as attaching to a heat sink of about 1.5 ° C / W.

  FIG. 4 shows a circuit configuration of a power conditioner according to the second embodiment of the present invention. The difference from the first embodiment is a connection location of the short-circuit diode 10. As described above, the short-circuit diode 10 only needs to be disposed on the input side of the converter 2, but if there is a circuit component on the input side of the short-circuit diode 10, a reverse current flows through a path including the component, In the example shown in FIG. 4, since a current also flows through the coil 41 constituting the input filter circuit 4, it is necessary to employ a coil 41 that can withstand the short-circuit current of the solar panel. Therefore, as shown in FIG. 1, it is preferable to arrange the short-circuit diode 10 at a position closer to the DC 2-wire input terminal (P, N) than other circuit components, and thereby a path that does not affect other components. Thus, a reverse current can flow.

  FIG. 5 shows a circuit configuration of a power conditioner according to the third embodiment of the present invention. In this embodiment, the control unit 11 of the power conditioner is operated by power supplied from the DC link unit 1 during normal power generation. On the other hand, when there is no DC input voltage, power is supplied from the system. Specifically, the power conditioner 2 includes a power lead-in wiring 12 for supplying DC power from the DC link unit 1 to the power input terminal of the control unit 11, and the wiring 12 is provided with a backflow prevention diode 13. During power generation, the control unit 11 is operated using power from the DC link unit 1 as a power source. Further, an auxiliary power supply circuit for rectifying the system power to DC power via a rectifying means 14 such as a diode bridge and supplying the power to the power input terminal of the control unit 11 is provided. Rectifying means 14 and a relay 15 for turning on and off the supply of system power are provided. The relay 15 is also controlled by the control unit 11. For example, if the voltage of the DC link unit 1 is less than the voltage necessary for continuing the operation of the control unit 11, the relay 15 is closed and controlled by receiving the supply of system power. The operation of the unit 11 can be performed. When the generated output voltage becomes sufficiently high, the relay 15 is controlled to open and the control unit 11 is operated by the generated power. The diode 13 is for preventing the system power from being supplied to the DC link unit 1 via the lead-in wiring 12 when the system power is supplied.

  Further, an input current sensor 16 capable of detecting the input current in both directions is provided on the DC power supply side from the short-circuit diode 10, and the input current sensor 16 is used to control the input current value for normal operation. And a reverse current when the DC power source is connected in positive and negative directions can be detected.

  Further, when the control unit 11 monitors the input current sensor 16 and detects the reverse current, the control unit 11 detects a buzzer device built in the control unit 11 or a display device 17 connected to the power conditioner. Thus, it is configured to notify that the connection to the DC 2-wire input terminal (P, N) is positive or negative, and thus the control unit 11 constitutes an informing means.

  According to the present embodiment, when the AC three-wire input terminals (U, O, W) are first wired to the system, power is supplied from the system to the control unit 11 and the control unit 11 is activated. Monitoring of incorrect connection of the DC input is started. In this state, if the DC power source is connected to the DC 2-wire input terminal (P, N) in the positive or negative direction, the control unit 11 performs a predetermined notification by detecting the reverse current. You can notice that there is.

  The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, the use of the connection terminal covered with the cover is not limited to the self-contained power generation output, and may be an input / output terminal for various uses, or may be an empty terminal. Further, the number of connection terminals covered with the cover may be one, or may be three or more. In the above embodiment, a plurality of connection terminals are provided in a row on one terminal block, but it is not always necessary to provide a terminal block.

9 Cover 10 Short-circuit diode 11 Control unit (notification means)
L1, L2 AC 2-wire terminal for self-sustained power generation covered with cover P, N DC 2-wire terminal on the left side of connection terminal covered with cover U, O, W Right side of connection terminal covered with cover AC 3-wire terminal

Claims (5)

There are at least six connection terminals arranged in a left and right row, and two adjacent ones of the connection terminals are DC two-wire terminals, and three adjacent ones of the connection terminals excluding the DC two-wire terminals are AC. In the power conditioner which is a three-wire terminal, at least one connection terminal covered with a removable cover is disposed between the DC two-wire terminal and the AC three-wire terminal, and the cover the number of the left connection terminals covered connection terminals and the number of right connection terminals Ri Do different, the DC two-line terminal is an input terminal for inputting the generated power of the DC output from the power generating unit The AC 3-wire terminal is an output terminal for outputting the generated power converted to AC power linked to the power system to the power system, and the DC 2-wire terminal is a connection covered with the cover. Located on the left side of the terminal, front Terminal AC 3-wire is disposed on the right side of the connection terminals covered with the cover, the number of the left connection terminals covered connection terminal in said cover power conditioner according to claim 2 Tsudea Rukoto. 2. The power conditioner according to claim 1 , wherein a diode having a cathode connected to the positive terminal side and an anode connected to the negative terminal side is provided between the connection terminals of the DC two-wire terminals. Power conditioner to do. 3. The power conditioner according to claim 1 or 2 , further comprising a notification unit that performs a predetermined notification when a reverse current flows through the DC two-wire terminal. The power conditioner according to any one of claims 1 to 3 , wherein the number of connection terminals covered by the cover is two, and the two connection terminals are for an AC two-wire for self-sustained power generation output. A power conditioner that is a terminal. 5. The power conditioner according to claim 4 , further comprising a ground wire terminal as the connection terminal, the DC 2-wire terminal, the AC 2-wire terminal, the AC 3-wire terminal, and the ground wire terminal. A power conditioner arranged in the order of

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