JP2016073028A - Distributed power supply system and power conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply power from a plurality of distributed power sources to a load at the time of outage without requiring perfect synchronization of the distributed power sources.SOLUTION: A distributed power supply system (10) comprises a first power conditioner (100) and a second power conditioner (200), each of which is connected to single-phase three-wire system wiring composed of a first voltage wire (U phase), a second voltage wire (W phase), and a neutral wire (O phase). At the time of autonomous operation, the first power conditioner (100) connects autonomous operation output of a single-phase two-wire system with the first voltage wire and the neutral wire; the second power conditioner (200) connects autonomous operation output of a single-phase two-wire system with the second voltage wire and the neutral wire; and the first power conditioner (100) outputs a voltage waveform having predetermined relation with a voltage waveform between the second voltage wire and the neutral wire to a point between the first voltage wire and the neutral wire.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a distributed power supply system and a power conditioner.

  2. Description of the Related Art In recent years, a power system that supplies power by providing a distributed power source such as a solar cell, a storage battery, and a fuel cell in a general house and interconnecting with a system is becoming widespread. In such a power system, when a power failure occurs in a system, power can be supplied from a distributed power source to a load such as an electric device by performing a self-sustaining operation.

  Ordinary houses are usually supplied with electric power by a single-phase three-wire from an electric power company. In the single-phase three-wire, AC 200V is supplied between the U phase and the W phase. Further, 100 V is supplied between the U phase and the neutral phase O phase, and 100 V is also supplied between the W phase and the O phase.

  In a distributed power source that is connected to a single-phase three-wire system, when the stand-alone output is also connected to the single-phase three-wire system, it usually has two independent output systems. 100V is supplied between the -O phases, and 100 V is supplied between the W-phase and the O-phase from the other self-supporting output. In this case, the distributed power supply system needs to have two DC / AC converters in order to supply AC power to the two independent power outputs.

  In addition, when a plurality of distributed power sources connected to a single-phase three-wire are also connected to the grid, an invention is proposed in which power is supplied to a load from a plurality of distributed power sources connected in parallel during a power failure. (See Patent Document 1).

JP 2005-295707 A

  However, in a configuration in which power is supplied to a load from a plurality of distributed power sources connected in parallel during a self-sustained operation, it is necessary to completely synchronize the voltage waveforms of the plurality of distributed power sources. In other words, not only the timing but also the amplitude and waveform must be completely aligned. Therefore, there has been a problem that a dedicated synchronization line is required and complicated control is required to accurately match the output waveform with the waveform of the master signal.

  An object of the present invention made in view of such a point is to provide a distributed power supply system and a power conditioner that can supply power from a plurality of distributed power supplies to a load without having to completely synchronize the plurality of distributed power supplies in the event of a power failure. It is to provide.

  A distributed power supply system according to an embodiment of the present invention includes a first power conditioner connected to a single-phase three-wire wiring composed of a first voltage line, a second voltage line, and a neutral line, and a second power conditioner. A distributed power supply system including a power conditioner, wherein the first power conditioner connects a single-phase two-wire self-sustained operation output to the first voltage line and the neutral line during a self-sustaining operation. The second power conditioner connects a single-phase two-wire self-sustained operation output to the second voltage line and the neutral line, and the first power conditioner is connected to the second voltage line and the neutral line. A voltage waveform having a predetermined relationship with the voltage waveform between the first and second lines is output between the first voltage line and the neutral line.

  The distributed power supply system according to the embodiment of the present invention includes a first power conditioner connected to a single-phase three-wire wiring composed of a first voltage line, a second voltage line, and a neutral line, and A distributed power supply system including a second power conditioner, wherein the first power conditioner has a voltage waveform between the first voltage line and the neutral line and the second voltage line during a self-sustaining operation. And a voltage waveform between the neutral line and the neutral line between the voltage line where the predetermined voltage waveform is not detected and the neutral line. Controlling to connect a self-sustained operation output, between the voltage line on which the predetermined voltage waveform is not detected and the neutral line, with respect to the voltage waveform between the other voltage line and the neutral line A voltage waveform having a predetermined relationship.

  In addition, the power conditioner according to the embodiment of the present invention has a single-phase three-wire wiring composed of a first voltage line, a second voltage line, and a neutral line, in parallel with other power conditioners. A DC / AC converter that converts DC power into AC power, a self-supporting switching relay that switches connection between the DC / AC converter and the single-phase three-wire wiring, A control unit that controls a self-supporting switching relay, wherein the control unit, during a self-sustained operation, a voltage waveform between the first voltage line and the neutral line, and the second voltage line and the neutral line. The self-contained switching relay is connected so that the output of the DC / AC converter is connected between the neutral line and the voltage line where the predetermined voltage waveform is not detected. Control and the predetermined voltage waveform is detected. Between the non toward the neutral line and the voltage line to be, and outputs a voltage waveform having a predetermined relationship to the voltage waveform between the neutral line and the other voltage line.

  According to the distributed power supply system and the power conditioner according to the present invention, it is possible to supply electric power from a plurality of distributed power supplies to a load without having to completely synchronize the plurality of distributed power supplies at the time of a power failure.

1 is a diagram illustrating a schematic configuration of a distributed power supply system according to a first embodiment of the present invention. It is a flowchart which shows an example of operation | movement of the distributed power supply system which concerns on 1st Embodiment of this invention. It is a figure which shows schematic structure of the distributed power supply system which concerns on 2nd Embodiment of this invention. It is a flowchart which shows an example of operation | movement of the distributed power supply system which concerns on 2nd Embodiment of this invention. It is a figure which shows the mode of the polarity of the voltage waveform output from a 1st power conditioner. It is a flowchart which shows a mode that the polarity of the voltage waveform output from a 1st power conditioner is controlled. It is a figure which shows schematic structure of the distributed power supply system which concerns on 3rd Embodiment of this invention. It is a flowchart which shows an example of operation | movement of the distributed power supply system which concerns on 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing a schematic configuration of a distributed power supply system 10 according to the first embodiment of the present invention. The distributed power supply system 10 includes a first power conditioner 100, a second power conditioner 200, a solar battery 300, a storage battery 400, a load 500, a load 600, a system-side circuit breaker 700, and a system 800. In FIG. 1, a solid line connecting each functional block indicates a power line, and a broken line indicates a communication line. The connection indicated by the communication line may be a wired connection or a wireless connection.

  The first power conditioner 100 and the second power conditioner 200 are connected to a single-phase three-wire wiring composed of a U phase, a W phase, and an O phase. The U phase, W phase, and O phase are also referred to as “first voltage line”, “second voltage line”, and “neutral line”, respectively.

  The first power conditioner 100 converts the DC power generated by the solar cell 300 into AC power in normal times, and supplies AC 200 V between the U-phase and W-phase of the single-phase three wires. Moreover, the 1st power conditioner 100 has an independent output terminal, and performs an autonomous operation at the time of a power failure. The first power conditioner 100 converts the DC power generated by the solar cell 300 into AC power during the independent operation, and supplies AC 100 V between the U-phase and the O-phase from the independent output terminal.

  The second power conditioner 200 converts DC power discharged from the storage battery 400 into AC power in normal times, and supplies AC 200 V between the U-phase and W-phase of the single-phase three-wire. Moreover, the 2nd power conditioner 200 can also charge the storage battery 400 by converting the alternating current power supplied from the system | strain 800 and / or the 1st power conditioner 100 into direct current power in normal time. Moreover, the 2nd power conditioner 200 has an independent output terminal, and performs an autonomous operation at the time of a power failure. The second power conditioner 200 converts the DC power discharged from the storage battery 400 into AC power during the independent operation, and supplies AC 100 V between the W-phase and the O-phase from the independent output terminal.

  The load 500 is an electric device connected between the U phase and the O phase. The load 500 is supplied with power only from the first power conditioner 100 during the independent operation. Although one load 500 is shown in FIG. 1, a plurality of loads 500 may be connected.

  The load 600 is an electrical device connected between the W phase and the O phase. The load 600 is supplied with electric power only from the second power conditioner 200 during the independent operation. Although one load 600 is shown in FIG. 1, a plurality of loads 600 may be connected.

  The system-side circuit breaker 700 interrupts the system 800 from the distributed power supply system 10 when the system 800 fails.

  The first power conditioner 100 includes a DC / DC converter 101, a DC / AC converter 102, a control unit 103, an interconnection relay 104, a self-supporting output relay 105, and a voltage sensor 106.

  The DC / DC converter 101 boosts or steps down the voltage of the direct current power supplied from the solar cell 300 and supplies it to the DC / AC converter 102.

  The DC / AC converter 102 is also called an inverter, and converts DC power supplied from the DC / DC converter 101 into AC power. The DC / AC converter 102 supplies AC 200 V between the U phase and the W phase via the interconnection relay 104 in a normal time. In addition, the DC / AC converter 102 supplies 100 V AC between the U phase and the O phase as a single-phase two-wire self-sustained operation output from the self-sustained output terminal via the self-sustained output relay 105 during the self-sustained operation.

  The control unit 103 controls and manages the entire first power conditioner 100, and can be configured by a processor, for example. The control unit 103 controls the DC / DC converter 101 and the DC / AC converter 102 and controls voltage waveforms (amplitude, phase, etc.) output from the DC / AC converter 102. Further, the control unit 103 controls on / off of the interconnection relay 104 and the independent output relay 105.

  Moreover, the control part 103 detects the voltage waveform which the 2nd power conditioner 200 is outputting between W phase-O phases with the voltage sensor 106 at the time of a self-sustained operation, and has a predetermined relationship with respect to the said voltage waveform. The DC / AC converter 102 is controlled to output a voltage waveform between the U phase and the O phase. Specifically, the control unit 103 controls the DC / AC converter 102 so that the polarity of the W phase voltage waveform based on the O phase is the same as that of the U phase voltage waveform based on the O phase. Control. Thus, in this embodiment, by controlling the voltage waveforms between the W-phase and the U-phase and between the U-phase and the O-phase to have the same polarity, as shown in FIG. 1, the first power conditioner 100 and Even if the O phase is shared with the second power conditioner 200, it is possible to normally output from each power conditioner during the independent operation. Thereby, an output can be obtained without connecting these two power conditioners in parallel during the independent operation. In the present embodiment, the DC / AC converter 102 is controlled based on the relationship that the polarity of the W-phase voltage waveform based on the O-phase and the U-phase voltage waveform based on the O-phase are the same. However, the polarity is not limited to that described above for the predetermined relationship. For example, instead of the polarity of the voltage waveform, the DC / AC converter 102 may be controlled so that the voltage value of the voltage waveform or the amplitude direction of the voltage waveform is the same.

  The interconnecting relay 104 is normally controlled to be in an on state, and connects the output of the DC / AC converter 102 to the U phase and the W phase. In addition, the interconnection relay 104 is controlled so as to be turned off at the time of a power failure, and disconnects the connection between the DC / AC converter 102 and the U phase and the W phase.

  The self-sustained output relay 105 is controlled so as to be in an off state in a normal state, and disconnects the connection between the output of the DC / AC converter 102 and the self-sustained output terminal. In addition, the self-sustained output relay 105 is controlled to be turned on during the self-sustaining operation, and connects the output of the DC / AC converter 102 to the self-sustained output terminal. The self-supporting output terminal is connected between the U-phase and the O-phase, and during the self-supporting operation, the voltage waveform output from the DC / AC converter 102 is supplied between the U-phase and the O-phase.

  The voltage sensor 106 detects a voltage waveform between the W phase and the O phase.

  The second power conditioner 200 includes a DC / DC converter 201, a DC / AC converter 202, a control unit 203, an interconnection relay 204, a self-supporting output relay 205, and a voltage sensor 206.

  The DC / DC converter 201 steps up or steps down the voltage of the DC power supplied from the storage battery 400 and supplies it to the DC / AC converter 202. Further, the DC / DC converter 201 can charge or charge the storage battery 400 by increasing or decreasing the voltage of the DC power supplied from the DC / AC converter 202 and supplying the voltage to the storage battery 400.

  The DC / AC converter 202 converts the DC power supplied from the DC / DC converter 201 into AC power. The DC / AC converter 202 is bidirectional and can also convert AC power supplied from the system 800 and / or the first power conditioner 100 into DC power. The DC / AC converter 202 supplies AC 200 V between the U phase and the W phase via the interconnection relay 204 in a normal time. Moreover, the DC / AC converter 202 supplies AC 100V between the W phase and the O phase as a single-phase two-wire self-sustained operation output from the self-sustained output terminal via the self-sustained output relay 205 during the self-sustained operation.

  The control unit 203 controls and manages the entire second power conditioner 200, and can be configured by, for example, a processor. The control unit 203 controls the DC / DC converter 201 and the DC / AC converter 202, and controls the voltage waveform (amplitude, phase, etc.) output from the DC / AC converter 202. Further, the control unit 203 controls on / off of the interconnection relay 204 and the self-sustained output relay 205.

  The interconnecting relay 204 is normally controlled to be turned on, and connects the output of the DC / AC converter 202 to the U phase and the W phase. In addition, the interconnection relay 204 is controlled to be in an off state at the time of a power failure, and disconnects the connection between the DC / AC converter 202 and the U phase and the W phase.

  The self-sustained output relay 205 is normally controlled to be in an off state, and disconnects the connection between the output of the DC / AC converter 202 and the self-sustained output terminal. In addition, the self-sustained output relay 205 is controlled to be turned on during the self-sustained operation, and connects the output of the DC / AC converter 202 to the self-sustained output terminal. The independent output terminal is connected between the W phase and the O phase, and the voltage waveform output from the DC / AC converter 202 is supplied between the W phase and the O phase during the independent operation.

  The voltage sensor 206 detects a voltage waveform between the U phase and the O phase.

  Next, the operation during the autonomous operation of the distributed power supply system 10 according to the first embodiment of the present invention will be described with reference to the flowchart shown in FIG.

  The voltage sensor 106 of the first power conditioner 100 detects a voltage waveform between the W phase and the O phase (step S101).

  The control unit 103 controls the DC / AC converter 102 so that the polarity of the voltage waveform output by the first power conditioner 100 between the U phase and the O phase is the same as the polarity of the voltage waveform between the W phase and the O phase. (Step S102).

  The DC / AC converter 102 outputs a voltage waveform between the U phase and the O phase from the self-supporting output terminal (step S103).

  Thus, according to the present embodiment, by controlling the voltage waveforms between the W phase and the O phase and between the U phase and the O phase to have the same polarity, as shown in FIG. Even if the O-phase is shared by 100 and the second power conditioner 200, it is possible to normally output from each power conditioner during the independent operation. Further, according to the present embodiment, during the autonomous operation, the autonomous operation output of the first power conditioner 100 is connected between the U phase and the O phase, and the autonomous operation output of the second power conditioner 200 is between the W phase and the O phase. Since they are connected, the two power conditioners are not connected in parallel during the autonomous operation. This eliminates the need to completely synchronize the outputs of the two inverters.

  Further, since the two power conditioners are not connected in parallel during the independent operation, the output power of each power conditioner during the independent operation can be fully utilized. That is, each power conditioner can be output up to an upper limit of 1500 W as defined by the Electricity Business Law.

  Further, since the two power conditioners are not connected in parallel during the independent operation, the output voltages of the power conditioners may be different voltages. For example, the output voltage of the first power conditioner 100 can be set to 100V, and the output voltage of the second power conditioner 200 can be set to 107V. If the output voltage is raised, the power supplied to the load can be increased, and if the output voltage is lowered, the power consumption of the load can be reduced.

  Further, since the two power conditioners are not connected in parallel during the independent operation, even if the output waveform of the first power conditioner 100 and the output waveform of the second power conditioner 200 are not completely synchronized, It can be used safely without problems such as reverse current flow.

  Moreover, since the 1st power conditioner 100 detects the voltage waveform which the 2nd power conditioner 200 outputs from a power line at the time of a self-sustained operation, a dedicated synchronizing signal line is not required. As a result, it is not necessary to provide a special function in the control unit, and the polarity of the voltage waveforms output by the two power conditioners can be made uniform even with software alone.

  In addition, since two power conditioners are not connected in parallel during self-sustained operation, the voltage waveform output by one power conditioner is measured as a master signal, and the voltage waveform output by itself is accurately measured. Complicated control such as matching becomes unnecessary. As a result, the processing burden on the CPU can be reduced.

  In the present embodiment, the case where the self-supporting output terminal of the first power conditioner 100 is connected between the U-phase and the O-phase, and the self-supporting output terminal of the second power conditioner 200 is connected between the W-phase and the O-phase. As described above, the self-supporting output terminal of the first power conditioner 100 is connected between the W-phase and the O-phase, and the self-supporting output terminal of the second power conditioner 200 is connected between the U-phase and the O-phase. There may be.

[Second Embodiment]
FIG. 3 is a diagram showing a schematic configuration of the distributed power supply system 20 according to the second embodiment of the present invention. The distributed power supply system 20 includes a first power conditioner 150, a second power conditioner 200, a solar battery 300, a storage battery 400, a load 500, a load 600, a system-side circuit breaker 700, and a system 800. In FIG. 3, a solid line connecting each functional block indicates a power line, and a broken line indicates a communication line. The connection indicated by the communication line may be a wired connection or a wireless connection.

  In the second embodiment, portions that are different from the first embodiment will be mainly described, and description of contents that are the same as or similar to those of the first embodiment will be omitted as appropriate.

  In the first embodiment, the self-supporting output terminal of the first power conditioner 100 is connected between the U-phase and the O-phase, and the self-supporting output terminal of the second power conditioner 200 is connected between the W-phase and the O-phase. . This connection is fixed, and the first power conditioner 100 detects the voltage waveform between the W phase and the O phase and controls the voltage waveform output between the U phase and the O phase in a state where the connection state is known. It was.

  In the second embodiment, the first power conditioner 150 is operated independently depending on whether the self-supporting output terminal of the second power conditioner 200 is connected between the U phase and the O phase or between the W phase and the O phase. Sometimes, the point of connection of the independent output of the first power conditioner 150 is different from that of the first embodiment in that it can be automatically connected to the one to which the independent output terminal of the second power conditioner 200 is not connected.

  Hereinafter, the 1st power conditioner 150 which concerns on 2nd Embodiment is demonstrated.

  The first power conditioner 150 includes a DC / DC converter 101, a DC / AC converter 102, a control unit 103, a voltage sensor 106, a voltage sensor 107, and a self-supporting switching relay 108.

  The DC / AC converter 102 supplies AC 200 V between the U phase and the W phase via the self-supporting switching relay 108 in a normal time. Further, the DC / AC converter 102 supplies AC 100 V between the U phase and the O phase or between the W phase and the O phase via the self-sustained switching relay 108 during the independent operation.

  The control unit 103 controls and manages the entire first power conditioner 150, and can be configured by a processor, for example. The control unit 103 controls the DC / DC converter 101 and the DC / AC converter 102 and controls voltage waveforms (amplitude, phase, etc.) output from the DC / AC converter 102. Further, the control unit 103 controls connection of the self-supporting switching relay 108. Details of the control of the control unit 103 will be described later.

  Independent switching relay 108 switches connection between DC / AC converter 102 and single-phase three-wire. In normal times, the self-supporting switching relay 108 is controlled to connect the DC / AC converter 102 between the U phase and the W phase. During the autonomous operation, the autonomous switching relay 108 is connected between the U phase and the O phase depending on whether the independent output terminal of the second power conditioner 200 is connected between the U phase and the O phase or between the W phase and the O phase. Connected between W phase and O phase. Specifically, during the self-sustained operation, when the self-sustained output terminal of the second power conditioner 200 is connected between the U-phase and the O-phase, the self-sustained switching relay 108 outputs the output of the DC / AC converter 102 to the W-phase. It is controlled to connect between the -O phases. In addition, during the independent operation, when the independent output terminal of the second power conditioner 200 is connected between the W phase and the O phase, the autonomous switching relay 108 outputs the output of the DC / AC converter 102 between the U phase and the O phase. Controlled to connect to. In the example shown in FIG. 3, during the autonomous operation, the autonomous output terminal of the second power conditioner 200 is connected between the W phase and the O phase, and accordingly, the DC / AC converter 102 of the first power conditioner 150 is connected. The self-supporting switching relay 108 is controlled so as to connect the output between the U phase and the O phase. In the above-described embodiment, the description has been given of the embodiment in which only the independent switching relay 108 is provided. However, an interconnection relay may be provided between the DC / AC converter 102 and the independent switching relay 108. With such a configuration, it becomes possible to forcibly cut off the system and load in the event of an abnormality.

  The voltage sensor 106 detects a voltage waveform between the W phase and the O phase.

  The voltage sensor 107 detects a voltage waveform between the U phase and the O phase.

  The control unit 103 detects the voltage waveform between the W phase and the O phase by the voltage sensor 106 and detects the voltage waveform between the U phase and the O phase by the voltage sensor 107 during the independent operation. Based on the voltage waveforms detected by the voltage sensors 106 and 107, the control unit 103 determines whether the self-supporting output terminal of the second power conditioner 200 is connected between the U phase and the O phase or between the W phase and the O phase. To do. Specifically, for example, if the effective value of the voltage waveform between the W phase and the O phase detected by the voltage sensor 106 is 90 [V] or more, the second power conditioner 200 is connected between the W phase and the O phase. It is determined that The same determination is made when the voltage sensor 107 detects a voltage waveform between the U phase and the O phase.

  When the control unit 103 determines that the self-supporting output terminal of the second power conditioner 200 is connected between the W phase and the O phase, the output of the DC / AC converter 102 is connected between the U phase and the O phase. The self-standing switching relay 108 is controlled. In addition, when the control unit 103 determines that the self-supporting output terminal of the second power conditioner 200 is connected between the U phase and the O phase, the output of the DC / AC converter 102 is connected between the W phase and the O phase. Thus, the self-supporting switching relay 108 is controlled.

  When the second power conditioner 200 is connected to the independent output terminal between the W phase and the O phase during the independent operation, the control unit 103 causes the voltage sensor 106 to cause the second power conditioner 200 to be connected between the W phase and the O phase. The output voltage waveform is detected, and the DC / AC converter 102 is controlled so that a voltage waveform having a predetermined relationship with the voltage waveform is output between the U phase and the O phase. Specifically, the control unit 103 controls the DC / AC converter 102 so that the polarity of the W phase voltage waveform based on the O phase is the same as that of the U phase voltage waveform based on the O phase. Control.

  In addition, when the second power conditioner 200 connects the self-sustained output terminal between the U-phase and the O-phase during the self-sustaining operation, the control unit 103 causes the voltage sensor 107 to make the second power conditioner 200 connect the U-phase-O. The voltage waveform output between the phases is detected, and the DC / AC converter 102 is controlled so that a voltage waveform having a predetermined relationship with the voltage waveform is output between the W phase and the O phase. Specifically, the control unit 103 controls the DC / AC converter 102 so that the polarity of the W phase voltage waveform based on the O phase is the same as that of the U phase voltage waveform based on the O phase. Control.

  Next, the operation during the autonomous operation of the distributed power supply system 20 according to the second embodiment of the present invention will be described with reference to the flowchart shown in FIG. The flowchart of FIG. 4 is executed before the first power conditioner 150 starts independent operation. The flowchart in FIG. 4 is a flow that also considers the possibility that three or more power conditioners are connected in parallel to the single-phase three-wire.

  The control unit 103 of the first power conditioner 150 determines whether or not there is a predetermined voltage waveform between the U phase and the O phase (step S201).

  When it determines with No in step S201, the control part 103 judges that the self-supporting output terminal of the 2nd power conditioner 200 is connected between W phase-O phase, and the voltage sensor 106 is between W phase-O phases. A voltage waveform is detected (step S202).

  The control unit 103 controls the DC / AC converter 102 so that the polarity of the voltage waveform output by the first power conditioner 150 between the U phase and the O phase is the same as the polarity of the voltage waveform between the W phase and the O phase. (Step S203).

  The DC / AC converter 102 outputs a voltage waveform between the U phase and the O phase (step S204).

  When it determines with Yes in step S201, the control part 103 determines whether there exists a predetermined voltage waveform between W phase-O phases (step S205). If it is determined Yes in step S205, it is determined that the voltage waveform is already supplied between the U phase and the O phase and between the W phase and the O phase by the other two power conditioners, and the control unit 103 The process is terminated without supplying a voltage waveform between the U phase and the O phase and between the W phase and the O phase. At this time, the voltage waveform of the first power conditioner 150 is already supplied by the other two power conditioners (for example, the second power conditioner 200 and the third power conditioner). May be displayed as a warning display.

  When it determines with No in step S205, the control part 103 detects the voltage waveform between U phase-O phases with the voltage sensor 107 (step S206).

  The control unit 103 controls the DC / AC converter 102 so that the polarity of the voltage waveform output by the first power conditioner 150 between the W phase and the O phase is the same as the polarity of the voltage waveform between the U phase and the O phase. (Step S207).

  The DC / AC converter 102 outputs a voltage waveform between the W phase and the O phase (step S208).

  As described above, according to the present embodiment, the connection destination of the self-sustained output of the first power conditioner 150 is automatically switched during the self-sustaining operation, so that wiring between the self-sustained output terminal and the distribution board becomes unnecessary. Members and construction work can be reduced.

  Moreover, since the connection destination of the self-sustained output of the first power conditioner 150 is automatically switched during the self-sustaining operation, it is possible to avoid a situation where a correct connection is not made due to a construction error.

(Polarity setting)
During the self-sustained operation, the first power conditioner 150 has the same polarity of the voltage waveform between the U phase and the O phase based on the O phase and the polarity of the voltage waveform between the W phase and the O phase based on the O phase. Thus, the DC / AC converter 102 is controlled. If the polarity of the voltage waveform between the U phase and the O phase with respect to the O phase is different from the polarity of the voltage waveform between the W phase and the O phase, the voltage waveform may not be output correctly and a desired output may not be obtained. is there. The control unit 103 detects the voltage waveform output from the second power conditioner 200, and executes the above control based on the detected voltage waveform. The control is performed depending on which voltage line is used as a reference when detecting the voltage waveform. The method is different.

  5A and 5B show examples of two types of control methods. FIGS. 5A and 5B are examples in the case where the second power conditioner 200 outputs a self-supporting output between the W phase and the O phase.

  FIG. 5A shows an example in which the voltage sensor 106 detects the voltage waveform between the W phase and the O phase with reference to the O phase. In this case, the control unit 103 makes the polarity of the voltage waveform between the U phase and the O phase with respect to the O phase the same as the polarity of the voltage waveform between the W phase and the O phase detected with the O phase as a reference. The DC / AC converter 102 is controlled.

  FIG. 5B shows an example in which the voltage sensor 106 detects the voltage waveform between the W phase and the O phase with reference to the W phase. In this case, the control unit 103 causes the polarity of the voltage waveform between the U phase and the O phase with respect to the O phase to be opposite to the polarity of the voltage waveform between the W phase and the O phase detected with reference to the W phase. The DC / AC converter 102 is controlled. By controlling in this way, as a result, the polarity of the voltage waveform between the W phase and the O phase based on the O phase and the polarity of the voltage waveform between the U phase and the O phase based on the O phase are the same polarity. Become. That is, regardless of whether the voltage sensor 106 detects the voltage waveform between the W-phase and the O-phase with reference to the O-phase or the W-phase as a reference, substantially the same voltage waveform with the same polarity is detected. It can be output between the U phase and the O phase.

  The manner in which the polarity of the voltage waveform to be output is set according to which voltage line is used as the reference to detect the voltage waveform will be described with reference to the flowchart shown in FIG. The flowchart illustrated in FIG. 6 is an example in the case where the self-supporting output terminal of the second power conditioner 200 is connected between the W phase and the O phase.

  The control unit 103 of the first power conditioner 150 acquires setting information indicating which line the voltage sensor 106 uses to detect the voltage waveform (step S301). The setting information may be stored in advance in the control unit 103 or a memory. Further, when the setting information is not stored in the control unit 103 or the like, by measuring the polarity of the output voltage with reference to the O phase during normal operation connected to the system, between the U phase and the O phase and the W phase- The setting information may be calculated from the relationship of the polarity of the voltage waveform between the O phases. Then, the obtained setting information may be stored in the control unit 103 or a memory.

  The control unit 103 determines whether or not the voltage sensor 106 detects a voltage waveform based on the O phase (step S302).

  When it determines with Yes in step S302, the control part 103 prescribes | regulates that the voltage sensor 106 detects a voltage waveform on the basis of O phase (step S303).

  When it determines with No in step S302, the control part 103 prescribes | regulates that the voltage sensor 106 detects a voltage waveform on the basis of W phase (step S304).

  The control unit 103 detects a voltage waveform by the voltage sensor 106 (step S305).

  The control unit 103 controls the polarity of the voltage waveform output from the DC / AC converter 102 in accordance with which line the voltage sensor 106 detects as a reference. When the voltage sensor 106 detects a voltage waveform based on the O phase, the control unit 103 outputs the voltage waveform with the same polarity as the polarity of the detected voltage waveform between the W phase and the O phase. The converter 102 is controlled. In addition, when the voltage sensor 106 detects a voltage waveform based on the W phase, the control unit 103 outputs a voltage waveform with a polarity opposite to the detected polarity between the W phase and the O phase. The converter 102 is controlled (step S306).

  The DC / AC converter 102 outputs a voltage waveform between the U phase and the O phase (step S307).

[Third Embodiment]
FIG. 7 is a diagram showing a schematic configuration of a distributed power supply system 30 according to the third embodiment of the present invention. The distributed power supply system 30 includes a first power conditioner 150, a second power conditioner 250, a solar battery 300, a storage battery 400, a load 500, a load 600, a system-side circuit breaker 700, and a system 800. In FIG. 7, a solid line connecting each functional block indicates a power line, and a broken line indicates a communication line. The connection indicated by the communication line may be a wired connection or a wireless connection.

  In the third embodiment, portions that are different from the second embodiment will be mainly described, and description of contents that are the same as or similar to those of the second embodiment will be omitted as appropriate.

  In the third embodiment, the second power conditioner 250 is also configured to include the self-supporting switching relay 208, similarly to the first power conditioner 150. The second power conditioner 250 includes a voltage sensor 207 that detects a voltage waveform between the W phase and the O phase in addition to the voltage sensor 206 that detects a voltage waveform between the U phase and the O phase.

  Moreover, in 3rd Embodiment, the control part 103 of the 1st power conditioner 150 and the control part 203 of the 2nd power conditioner 250 are connected by the communication line, and can exchange information.

  The first power conditioner 150 according to the third embodiment detects the voltage waveform between the U-phase and the O-phase and the voltage waveform between the W-phase and the O-phase during the self-sustaining operation, and determines the connection destination of the second power conditioner 250. Instead of determining, whether the autonomous operation output of the second power conditioner 250 is connected between the U phase and the O phase or between the W phase and the O phase from the control unit 203 of the second power conditioner 250 Get configuration information. FIG. 7 shows a case where two power conditioners are connected in parallel to a single-phase three-wire, but three or more power conditioners are connected in parallel to a single-phase three-wire. May be. In this case, the first power conditioner 150 is connected to the second power conditioner 250 and the power conditioner connected in parallel to the other single-phase three wires, where the independent operation output is connected (U Phase-O phase, W-phase-O phase, and the like).

  With reference to the flowchart shown in FIG. 8, the operation at the time of self-sustaining operation of the distributed power supply system 30 according to the third embodiment of the present invention will be described. The flowchart of FIG. 8 is executed before the first power conditioner 150 starts independent operation. Note that the flowchart of FIG. 8 is a flow that also considers the possibility that three or more power conditioners are connected in parallel to the single-phase three-wire.

  The control unit 103 of the first power conditioner 150 outputs the independent operation output of each power conditioner between the U-phase and the O-phase from all other power conditioners connected in parallel to the single-phase three-wire. Or whether it is output between the W phase and the O phase (step S401).

  Based on the acquired information, the control unit 103 determines whether or not voltage waveforms are output from other power conditioners both between the U phase and the O phase and between the W phase and the O phase (step S402).

  If it is determined Yes in step S402, it is determined that the voltage waveform has already been supplied between the U phase and the O phase and between the W phase and the O phase by the other two power conditioners. The process ends without supplying a voltage waveform between the U-phase and the O-phase and between the W-phase and the O-phase. At this time, the voltage waveform of the first power conditioner 150 is already supplied by the other two power conditioners (for example, the second power conditioner 250 and the third power conditioner). May be displayed as a warning display.

  When it determines with No in step S402, the control part 103 determines whether the voltage waveform is output from the other power conditioner between U phase-O phases based on the acquired information (step S403). .

  When it determines with Yes in step S403, the control part 103 detects the voltage waveform between U phase-O phases with the voltage sensor 107 (step S404).

  The control unit 103 controls the DC / AC converter 102 so that the polarity of the voltage waveform output by the first power conditioner 150 between the W phase and the O phase is the same as the polarity of the voltage waveform between the U phase and the O phase. (Step S405).

  The DC / AC converter 102 outputs a voltage waveform between the W phase and the O phase (step S406).

  When it determines with No in step S403, the control part 103 determines whether the voltage waveform is output from the other power conditioner between W phase-O phase based on the acquired information (step S407). .

  When it determines with Yes in step S407, the control part 103 detects the voltage waveform between W phase-O phases with the voltage sensor 106 (step S408).

  The control unit 103 controls the DC / AC converter 102 so that the polarity of the voltage waveform output by the first power conditioner 150 between the U phase and the O phase is the same as the polarity of the voltage waveform between the W phase and the O phase. (Step S409).

  The DC / AC converter 102 outputs a voltage waveform between the U phase and the O phase (step S410).

  When it is determined No in step S407, since the voltage waveform is not yet output between the U phase and the O phase and between the W phase and the O phase, the control unit 103 determines that the U phase and the O phase and the W phase and the O phase are not output. A voltage waveform is output to any of the phases (step S411).

  As described above, in this embodiment, the control unit 103 of the first power conditioner 150 determines whether the self-sustained operation output of the other power conditioner is output between the U phase and the O phase or between the W phase and the O phase. Information can be acquired. Thereby, in this embodiment, in a state where the voltage cannot be detected yet before each power conditioner is output during the independent operation, for example, immediately before the second power conditioner 250 outputs by the independent operation between the W phase and the O phase. Even if it exists, generation | occurrence | production of malfunction which outputs the 1st power conditioner 150 between W phase-O phases can be reduced.

  In the third embodiment, the second power conditioner 250 is described as including the self-supporting switching relay 208. However, if the control unit 203 can communicate with the first power conditioner 150, the first embodiment and As in the second power conditioner 200 described in the second embodiment, a configuration having the interconnection relay 204 and the independent output relay 205 instead of the independent switching relay 208 may be used.

(Control by HEMS)
FIG. 7 illustrates a configuration in which the control unit 103 of the first power conditioner 150 and the control unit 203 of the second power conditioner 250 directly communicate with each other to exchange information. However, for example, HEMS (Home Energy Management) A control device such as (System) may be provided outside, and the HEMS may control the control unit 103 and the control unit 203. In this case, the information to be communicated is information that can be handled even if the communication speed is relatively slow, such as the power generation state of the distributed power supply, the remaining capacity of the storage battery, etc. Compared with information on a certain voltage waveform, the calculation burden on the control unit is also small. In FIG. 7, two power conditioners are connected to the single-phase three-wire wiring. However, for example, three power conditioners may be connected to the single-phase three-wire wiring. . For example, the third power conditioner may be connected to the fuel cell.

  When the HEMS is configured to control the control unit 103 and the control unit 203, it may be automatically determined which distributed power source is connected to which voltage line, and a suitable type of distributed power source may be connected. Such control is also effective for determining the priority when three or more distributed power sources are connected to single-phase three-wire wiring.

  An example of specific determination / control processing will be described below.

  Step 1: Before performing independent operation (normal time), the transition of the power consumption of the load 500 connected between the U phase and the O phase is stored in a memory, and a load that continuously consumes power such as a refrigerator Determine if there is.

  Step 2: Before performing the independent operation (normal time), the transition of the power consumption of the load 600 connected between the W phase and the O phase is stored in a memory, and a load that continuously consumes power such as a refrigerator Determine if there is.

  Step 3: When switching to independent operation, check the distributed power sources that can output autonomous operation. For example, when a solar power generation device, a power storage device, and a fuel cell device are connected one by one, the HEMS performs information communication with each distributed power source and determines whether or not a self-sustained operation output is possible. Specifically, for example, information on what kind of power generation state is obtained from the solar power generation device, information on the remaining battery level is obtained from the power storage device, and gas supply is stopped from the fuel cell device. Information is acquired, and the HEMS determines the priority order based on the acquired information.

  Step 4: Priorities are those that can output stably for a long time (fuel cell device is good, power storage device is suitable depending on remaining amount, solar power generation device is not suitable), one that can withstand driving of large capacity load (power storage device is good, Solar power generators are unsuitable for power systems as soon as they are exposed to sunlight. Equipment that does not break down even if the load fluctuates severely (solar power generators and power storage devices are good, and fuel cell devices have sudden changes in output. It is difficult to deal with). When there are two power storage devices, it is determined that the priority order with the larger capacity is higher.

  Step 5: Check the power consumption tendency between the U phase and the O phase and between the W phase and the O phase, and the priority order, and determine which distributed power source is connected between the U phase and the O phase (or between the W phase and the O phase). judge. For example, it is determined that it is necessary to continuously supply power to a highly necessary load such as a refrigerator, and a fuel cell device or a power storage device that can stably output for a long time to the voltage line side to which the refrigerator is connected Assign. A photovoltaic power generation device and a power storage device are allocated to the voltage line side to which a load that is large but not essential, such as an air conditioner, is connected. Further, when the fluctuation of the total power consumption is large due to the influence of the load connected in parallel with the refrigerator, it is determined that the fuel cell device is not suitable, and the power storage device is allocated.

  Step 6: After performing the determination of Step 1 to Step 5 above with HEMS, control is performed so that the first distributed power source (or the second distributed power source) is connected between the U phase and the O phase (or between the W phase and the O phase). To do. Then, after starting the first distributed power supply, the second distributed power supply is started. At this time, since the second distributed power supply can automatically switch the connection to the voltage line side on which the first distributed power supply is not connected, the connection destination of the second distributed power supply need not be designated from the HEMS. . Further, even when there are three or more distributed power sources, there is no problem because only one unit is instructed to start as the second distributed power source.

  In this way, by connecting the first distributed power source and the second distributed power source to the voltage line side (load side) suitable for each characteristic, more stable power supply can be realized. Further, by combining the output characteristics on the supply side and the power consumption characteristics of the load, the time during which the distributed power source can be driven can be extended. Also, an optimal distributed power source can be selected according to the situation, such as assigning a solar power generation device at daytime and assigning a power storage device at night.

(Other examples of control by HEMS)
A photovoltaic power generation apparatus is connected as a first distributed power source between the U phase and the O phase to start power feeding. A fuel cell device is connected as a second distributed power source between the W phase and the O phase to start power feeding. A power storage device is prepared as a third distributed power source. When the HEMS detects a power shortage of the first distributed power supply or the second distributed power supply, the connection destination of the third distributed power supply is set to the power line connected to the distributed power supply in which the power shortage is detected, and distributed at the timing of the zero cross point. Switch power. By controlling to return to the original distributed power supply when the power shortage is resolved, the power of the distributed power supply can be used for a long time.

  As described above, it is also effective to use the third distributed power supply as a backup power supply for the first distributed power supply or the second distributed power supply as necessary. When switching the distributed power source, the distributed power source can be seamlessly shifted by switching at the zero cross point.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each component, each step, etc. can be rearranged so that there is no logical contradiction, and multiple components, steps, etc. can be combined or divided into one It is. Further, although the present invention has been described mainly with respect to the apparatus, the present invention can also be realized as a method, a program executed by a processor included in the apparatus, or a storage medium storing the program, and is within the scope of the present invention. It should be understood that these are also included.

  Moreover, in this embodiment, although the solar cell was connected to the 1st power conditioner (100, 150), and the case where the storage battery was connected to the 2nd power conditioner (200, 250) was mentioned as an example, it demonstrated. This is just an example. Other types of power generators may be connected to the first power conditioner and the second power conditioner. Further, the same type of power generation device may be connected to the first power conditioner and the second power conditioner (for example, solar cells may be connected to both power conditioners).

  In the present embodiment, AC 200 V is supplied between the U-phase and W-phase of the single-phase, three-wire system in normal times, and AC 100 V is supplied between the U-phase and O-phase and between the W-phase and O-phase in the self-sustained operation. Although described as a thing, the value with 200V and 100V is an example, and may be a value which changes with standards.

10, 20, 30 Distributed power supply system 100, 150 First power conditioner 101 DC / DC converter 102 DC / AC converter 103 Control unit 104 Interconnection relay 105 Autonomous output relay 106 Voltage sensor 107 Voltage sensor 108 Autonomous switching relay 200, 250 Second power conditioner 201 DC / DC converter 202 DC / AC converter 203 Control unit 204 Interconnection relay 205 Autonomous output relay 206 Voltage sensor 207 Voltage sensor 208 Autonomous switching relay 300 Solar battery 400 Storage battery 500 Load 600 Load 700 System side circuit breaker 800 lines

Claims (6)

A distributed power supply system including a first power conditioner and a second power conditioner connected to a single-phase three-wire wiring composed of a first voltage line, a second voltage line, and a neutral line,
During autonomous operation,
The first power conditioner connects a single-phase two-wire self-sustained operation output to the first voltage line and the neutral line,
The second power conditioner connects a single-phase two-wire self-sustained operation output to the second voltage line and the neutral line,
The first power conditioner generates a voltage waveform having a predetermined relationship with the voltage waveform between the second voltage line and the neutral line between the first voltage line and the neutral line. Distributed power supply system to output. A distributed power supply system including a first power conditioner and a second power conditioner connected to a single-phase three-wire wiring composed of a first voltage line, a second voltage line, and a neutral line,
The first power conditioner is in a self-sustaining operation.
Detecting a voltage waveform between the first voltage line and the neutral line, and a voltage waveform between the second voltage line and the neutral line;
Control is performed so as to connect a single-phase two-wire self-sustained operation output of the first power conditioner between a voltage line on which a predetermined voltage waveform is not detected and the neutral line,
A voltage waveform having a predetermined relationship with respect to the voltage waveform between the other voltage line and the neutral line is output between the voltage line on which the predetermined voltage waveform is not detected and the neutral line. Distributed power system. The distributed power supply system according to claim 2,
The first power conditioner includes a first control unit,
The second power conditioner includes a second control unit,
The first control unit and the second control unit can communicate with each other;
In the independent operation, the first control unit outputs an independent operation output of the second power conditioner between the first voltage line and the neutral line from the second control unit, and the second voltage. A distributed power supply system is characterized in that information on whether a wire is connected between the wire and the neutral wire is acquired.   4. The distributed power supply system according to claim 1, wherein the first power conditioner generates a voltage waveform between the second voltage line and the neutral line with reference to the neutral line. 5. A distributed power supply system that detects and outputs a voltage waveform having the same polarity as the voltage waveform between the first voltage line and the neutral line with reference to the neutral line.   4. The distributed power supply system according to claim 1, wherein the first power conditioner is a voltage waveform between the second voltage line and the neutral line with respect to the second voltage line. 5. And a voltage waveform having a polarity opposite to that of the voltage waveform is output between the first voltage line and the neutral line with reference to the neutral line. A power conditioner that is connected in parallel to another power conditioner to a single-phase three-wire wiring composed of a first voltage line, a second voltage line, and a neutral line,
A DC / AC converter for converting DC power into AC power;
A self-supporting switching relay that switches connection between the DC / AC converter and the single-phase three-wire wiring;
A control unit for controlling the self-standing switching relay,
The control unit, at the time of independent operation,
Detecting a voltage waveform between the first voltage line and the neutral line, and a voltage waveform between the second voltage line and the neutral line;
Controlling the self-sustained switching relay so that an output of the DC / AC converter is connected between a voltage line on which a predetermined voltage waveform is not detected and the neutral line;
A voltage waveform having a predetermined relationship with respect to the voltage waveform between the other voltage line and the neutral line is output between the voltage line on which the predetermined voltage waveform is not detected and the neutral line. Inverter.

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