JP2016100990A - Power conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conditioner which allows for simplification of construction effort even when using a connection box function incorporating a power conditioner, and when an external step-up connection box is connected with a terminal block.SOLUTION: In a power conditioner 1 where a plurality of input terminals 6a for power generation parts and input terminals 8a for step-up connection box are electrically connected in parallel with the input side of a power conversion part, a switch device 12 capable of open/close control is provided in the way of individual wiring 11 to the input terminals 8a for step-up connection box. When generated power is inputted to the input terminals 8a for step-up connection box, the switch device 12 is controlled to close state, and when the generated power is not inputted from a step-up connection box 7 to the input terminals 8a for step-up connection box, but inputted to at least one input terminal 6a for power generation part, the switch device 12 is controlled to open state by a control section 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power conditioner that interconnects a power generation output of a power generation unit such as a solar battery with a power system.

  For example, Patent Literature 1 below discloses a power conditioner (power converter) having a junction box function in a housing. This conventional power conditioner includes a plurality of switches for connecting a plurality of solar cell strings, and the plurality of switches are connected in parallel to the input side of the power adjustment unit, and the primary side of the plurality of switches When a plurality of solar cell strings are connected to each other, the outputs of the solar cell strings are collected on the secondary side of the plurality of switches and supplied to the power adjustment unit. Such a connection form can be connected with a single power conditioner without providing an external connection box, especially when constructing a plurality of solar cell strings having the same output voltage, thereby reducing the introduction cost of the system. It has the advantage of being able to.

  In addition, the conventional power conditioner is provided with a terminal block for connecting a boost junction box for connecting a boost junction box in parallel with the plurality of switches, in addition to the switch. When connecting solar cell strings of different sizes, the generated power boosted and aggregated to a predetermined voltage by the boost junction box can be input via the terminal block. With this configuration, the current capacity of each switch is What is necessary is just to employ | adopt what match | combined with the rated output current of one solar cell string, and can suppress the increase in cost by arrange | positioning several components, such as a switch of an excessive allowable current.

  In addition, the terminal block is wired to the power adjustment unit via the coupling switch. When the booster connection box is not connected to the terminal block, the coupling switch is switched to the shut-off state, so that multiple switching It is possible to prevent the voltage input from the container from being applied to the terminal block.

JP 2013-229953 A

  When connecting a plurality of solar cell strings to the terminal block via a boost connection box, it is necessary to manually switch the coupling switch to a conductive state, but the boost connection box is also provided with a plurality of switches. In addition, it is necessary to perform the switching operation of the coupling switch of the power conditioner together with the switching operation of the switch of the boosting connection box at the time of connection work to the boosting connection box.

  In addition, when connecting multiple solar cell strings directly to multiple inverter switches, if you forget to switch the coupling switch to the shut-off state, the exposed terminal block There is a problem that the power generation output voltage is applied.

  Therefore, the present invention has a connection box function that can simplify the construction work both when using the connection box function with a built-in inverter and when connecting an external step-up connection box to the terminal block. It aims to provide a power conditioner.

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

  That is, the present invention provides an alternating current in which a plurality of power generation unit input terminals to which a plurality of power generation units can be connected respectively and a boost connection box input terminal to which a boost connection box can be connected are connected to the power system. In the power conditioner electrically connected in parallel to the input side of the power conversion unit for converting to power, a switch device capable of opening and closing control provided in the middle of the individual wiring to the input terminal for the boost connection box, A control unit that controls opening and closing of the switch device, and the control unit controls the switch device to be closed when the generated power is input to the input terminal for the boost connection box, and boosts from the boost connection box. When the generated power is not input to the connection box input terminal and the generated power is input to at least one power generation unit input terminal, the switch device is configured to be controlled to be open. And it is characterized in bets (claim 1).

  The power generation unit input terminal may be constituted by a primary side terminal of a switch that can be connected to each power generation unit, and a terminal block including a plurality of power generation unit input terminals is provided for each power generation unit. You may provide separately from the switch provided in each separate wiring to an input terminal.

  According to the power conditioner of the present invention, when connecting a plurality of power generation units having the same output voltage, an external connection box becomes unnecessary by connecting the plurality of power generation units to the power generation unit input terminals. , System introduction cost can be reduced. On the other hand, when connecting a plurality of power generation units having different output voltages, the plurality of power generation units are first connected to a plurality of input terminals of the boost connection box, respectively, and the output terminal of the boost connection box and the boost connection of the power conditioner are connected. Connect the input terminal for the box with wiring. With this configuration, the allowable current capacity of a plurality of power generation unit input terminals and related wiring and switches can be set according to the power generation capacity of one power generation unit. While it is possible to adopt relatively low-cost and small-sized input terminals and related wiring and switches, etc., input terminals corresponding to large-capacity generated power input from the boost junction box are for dedicated boost junction boxes By using one input terminal, an increase in cost can be suppressed. Furthermore, since the control unit is configured to automatically open and close the switch device provided in the middle of the individual wiring to the input terminal for the boost connection box, or directly connect a plurality of power generation units to the power generation unit input terminal, Alternatively, it is not necessary to perform the switching operation depending on whether it is connected to the input terminal for the boost connection box via the boost connection box, and various problems due to forgetting to switch or the like do not occur.

  In the power conditioner of the present invention, it is preferable that the switch device is configured to be in a closed state when there is no control signal from the control unit (Claim 2). According to this, even when the control unit is operated by the generated power of the power generation unit and a plurality of power generation units are connected to the input terminal for the boost connection box via the boost connection box, even when the control unit is in the power-off state. The generated power can be input from the boost junction box input terminal, and the power can be supplied to the control unit to start the control unit.

  Further, the control unit may have a communication function for communicating with the step-up connection box, and may be configured to control the switch device to an open state based on communication with the step-up connection box (claim). Item 3). According to this, when communication with the step-up junction box is not established in the starting process of the control unit or when information indicating that the power generation operation is performed is not received even if communication is established, the control unit is supplied. Since the operating power that is being input can be regarded as being input from the power generation unit input terminal, the voltage of the generated power input to the power generation unit input terminal is boosted by controlling the switch device to the open state. It is possible to prevent application to the connection box input terminal and to prevent occurrence of a short circuit or the like in the boost connection box input terminal.

  Further, an input current sensor for detecting an input current from the input terminal for the boost junction box is further provided, and the control unit controls the switch device to be in an open state when a detection value of the input current sensor is less than a predetermined value. (Claim 4). Even in such a configuration, when the detected value of the input current sensor that detects the input current from the input terminal for the boost junction box is less than a predetermined value, the operating power supplied to the control unit is from the power generation unit input terminal. Since it can be regarded as being input, the voltage of the generated power input to the power generation unit input terminal is applied to the boost connection box input terminal by controlling the switch device to the open state. And the occurrence of a short circuit or the like at the input terminal for the step-up junction box can be prevented.

  As described above, according to the power conditioner according to claim 1 of the present invention, the allowable current capacity of a plurality of power generation unit input terminals and related wiring and switches is the power generation capacity of one power generation unit. While it is possible to adopt a relatively low cost and small size as these multiple power generation unit input terminals and related wiring and switches, etc., large-capacity power generation input from the boost junction box An increase in cost can be suppressed by using one dedicated input terminal for a boost connection box as an input terminal corresponding to electric power. Furthermore, since the control unit is configured to automatically open and close the switch device provided in the middle of the individual wiring to the input terminal for the boost connection box, or directly connect a plurality of power generation units to the power generation unit input terminal, Alternatively, it is not necessary to perform the switching operation depending on whether it is connected to the input terminal for the boost connection box via the boost connection box, and various problems due to forgetting to switch or the like do not occur.

  In the power conditioner according to claim 2 of the present invention, in particular, the control unit is operated by the generated power of the power generation unit, and a plurality of power generation units are connected to the input terminal for the boost connection box via the boost connection box. When connected, even when the control unit is in a power-off state, the generated power can be input from the input terminal for boost connection box, and the power can be supplied to the control unit to start the control unit.

  Further, according to the power conditioner according to claim 3 of the present invention, information indicating that the power generation operation is performed even when communication with the step-up connection box is not established or when communication is established in the starting process of the control unit, etc. The operating power supplied to the control unit can be regarded as being input from the power generation unit input terminal, so that the power generation unit input can be controlled by controlling the switch device to the open state. It is possible to prevent the voltage of the generated power input to the terminal from being applied to the input terminal for the boost junction box, and to prevent occurrence of a short circuit or the like at the input terminal for the boost junction box.

  According to the power conditioner of claim 4 of the present invention, when the detected value of the input current sensor that detects the input current from the input terminal for the boost junction box is less than the predetermined value, it is supplied to the control unit. Since the operating power that is being input can be regarded as being input from the power generation unit input terminal, the voltage of the generated power input to the power generation unit input terminal is boosted by controlling the switch device to the open state. It is possible to prevent application to the connection box input terminal and to prevent occurrence of a short circuit or the like in the boost connection box input terminal.

It is a block diagram which shows the schematic circuit structure of the power conditioner which concerns on one 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 schematic circuit configuration of a power generation system in which a plurality of power generation units 2 are connected to a power conditioner 1 according to an embodiment of the present invention. In addition, the electric power generation part 2 shown with the virtual line in the figure has shown the example of a connection in the case of connecting several electric power generation parts with the same output voltage, and the electric power generation part 2 shown with the continuous line has several different output electric power. The example of a connection in the case of connecting this electric power generation part is shown.

  Each power generation unit 2 may have a conventionally known appropriate configuration, and is generally configured as a solar cell string formed by connecting a plurality of solar cell modules in series or in parallel, and is installed on a roof of a building or the like. The

  The power conditioner 1 includes a power conversion circuit 4 (power conversion unit) that converts DC power generated and output by the power generation unit 2 into AC power that is grid-connected to the commercial power system 3 and outputs the AC power to the system 3, and the power conversion A control unit 5 for controlling the operation of the circuit 4, a plurality of switches 6 having a power generation unit input terminal 6a for directly connecting a plurality of power generation units 2 having the same output voltage without going through an external connection box, And a terminal block 8 having a pair of boost connection box input terminals 8a for connecting a plurality of power generation units 2 having different output voltages via an external boost connection box 7. The power conversion circuit 4 may have a conventionally known appropriate configuration, and in general, a DC / DC converter 4A configured by a boost chopper circuit or the like, a DC / AC inverter 4B configured by a bridge inverter or the like, It is mainly composed of a disconnection protection relay 4C and the like.

  The plurality of pairs of power generation unit input terminals 6 a and the pair of boost connection box input terminals 8 a are electrically connected in parallel to the input side of the power conversion circuit 4. The control unit 5 is configured to operate using the generated power input from any one of the input terminals 6a and 8a as a power source. When the power generation unit 2 is not connected or is connected, the switch 6 is opened. If the power generation unit 2 is not generating power, such as at night, even if the connection work is completed, the operation of the control unit 5 stops due to power interruption, and when the generated power is supplied, the control unit 5 Is activated to start various controls. Note that the control unit 5 may be configured to operate with commercial power supplied from the system 3.

  Each switch 6 can be configured by a switch that can be switched to open / close, and when the power generation unit 2 is connected to the power generation unit input terminal 6a by wiring, the switch 6 is switched to the open state so that it can be used during wiring work. It can be used to prevent current from flowing. A rectifier 10 for preventing backflow is provided in the middle of the individual wiring 9 to each switch 6, and in the illustrated example, the rectifier 10 is provided on the ground side wiring.

  On the other hand, a switch device 12 that can be controlled to open and close by a control signal from the control unit 5 is provided in the middle of the individual wiring 11 to the input terminal 8a for the boost connection box. As the switch device 12, in addition to an electromagnetic contactor, an electromagnetic switch, various relays, and a power semiconductor switching element, the switch device 12 is switched between an open state (electric circuit interruption state) and a closed state (electric circuit conduction state) by a control signal from the control unit. Any switchable switch can be used. Preferably, when there is no control signal from the control unit 5 (for example, when the control unit 5 is in a power-off state), the closed state is established, and when the HIGH signal is output from the control unit 5 as the control signal, the open state is established. It is preferable to use a normally closed contact type.

  In the connection configuration in which the plurality of power generation units 2 are connected via the external boosting connection box 7, the control unit 5 of the power conditioner 1 and the control unit 7A of the boosting connection box 7 are communicably connected. Then, the control unit 5 of the power conditioner 1 controls the switch device 12 to be closed when the generated power is input to the step-up connection box input terminal 8a and from the step-up connection box 7 to the step-up connection box input. When the generated power is not input to the terminal 8a and the generated power is input to at least one power generation unit input terminal 6a, the switch device 12 is controlled to be in an open state. Such switching control of the switch device 12 may be performed all the time during the startup of the control unit 5, but in the startup process at the time of startup of the control unit 5, it is determined whether the switch device 12 is opened or closed. It is also possible to configure the control so that the state determined in the startup process is held thereafter.

  The specific conditions for the determination may be appropriate. For example, when communication between the control unit 5 of the power conditioner 1 and the control unit 7A of the boost connection box 7 is established, the boost connection box 7 Since it exists, it can be determined that the generated power is being input from the boost connection box 7 to the boost connection box input terminal 8a. In addition, when the information indicating that the power generation operation is performed is received from the control unit 7A of the boost connection box 7 instead of simply determining by establishment of communication, the boost connection box 7 is connected to the boost connection box input terminal 8a. It can be determined that the generated power is input. In addition, when the communication cannot be established or when the information indicating that the power generation operation is performed is not received from the control unit 7A of the boost connection box 7, the generated power is input to the boost connection box input terminal 8a. Therefore, it can be determined that the generated power is input to at least one power generation unit input terminal 6a.

  Further, a current sensor 13 is provided in the middle of the individual wiring 11 to the step-up connection box input terminal 8a, and the detected value of the current sensor 13 is detected even though the generated power is supplied to the control unit 5 and the control unit 5 is activated. Is less than a predetermined value (for example, less than the current corresponding to the power consumption of the control unit 5), no generated power is input to the boost connection box input terminal 8a and at least one power generation unit input terminal It can also be determined that the generated power is input to 6a. Furthermore, the determination based on the detection value of the current sensor 13 and the determination based on the communication with the boost connection box 7 may be combined.

  According to the power conditioner 1 of the present embodiment, when a plurality of power generation units 2 are connected to the power generation unit input terminal 6a (see the phantom line in the drawing), the power generation unit 2 is connected to the power generation unit input terminal 6a. The switch device 12 is controlled to be in the open state. Therefore, it is possible to prevent the voltage of the generated power from being applied to the open step-up junction box input terminal 8a, and it is possible to avoid occurrence of a short circuit or the like at the terminal 8a.

  On the other hand, when the plurality of power generation units 2 are connected to the boost connection box input terminal 8a via the boost connection box 7, the power generation unit 2 is connected to the boost connection box input terminal 8a in the process of starting the control unit 5. Is determined to be connected, and holding control is performed while the switch device 12 is closed.

  Thus, by automatically performing the switching operation of the switch device 12 for switching the step-up junction box input terminal 8a to be electrically connected to the input side of the power conversion circuit 4 or to be electrically disconnected, Switching operation at the time of maintenance or the like becomes unnecessary, and convenience during work can be improved.

  The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Power conditioner 2 Power generation part 3 Electric power system 4 Power conversion part 5 Control part 6a Power generation part input terminal 7 Boosting connection box 8a Boosting connection box input terminal 11 Individual wiring 12 to boosting connection box input terminal 12 Switch device

Claims (4)

Power conversion in which a plurality of power generation unit input terminals to which a plurality of power generation units can be connected and a boost connection box input terminal to which a boost connection box can be connected converts the generated power into AC power linked to the power system In the power conditioner electrically wired in parallel to the input side of the section,
A switching device provided in the middle of the individual wiring to the input terminal for the boost junction box and capable of controlling opening and closing, and a control unit for controlling the opening and closing of the switch device, the control unit being connected to the input terminal for the boost junction box When the generated power is input, the switch device is controlled to be closed, and no generated power is input from the boost connection box to the boost connection box input terminal, and power is generated to at least one power generation unit input terminal. A power conditioner configured to control the switch device to an open state when electric power is input.   The power conditioner according to claim 1, wherein the switch device is configured to be in a closed state when there is no control signal from the control unit.   The power conditioner according to claim 2, wherein the control unit has a communication function of communicating with the boosting connection box, and is configured to control the switch device to an open state based on communication with the boosting connection box. A power conditioner characterized by   The power conditioner according to claim 2, further comprising an input current sensor that detects an input current from an input terminal for a boost junction box, wherein the control unit has a detection value of the input current sensor that is less than a predetermined value. The power conditioner is configured to control the switch device to an open state.

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