JP2017046544A - Power conditioner and power management device - Google Patents

Abstract

To enable independent operation simultaneously with a plurality of distributed power sources without impairing versatility. A power conditioner 100 according to the present invention is used by being connected to a system 40 in parallel with another power conditioner 20, performing a self-sustaining operation at the time of a power failure, supplying power to a load 25, and The power conversion unit 103 that converts electric power into AC power, the control unit 105 that executes a detection operation for determining whether or not a power outage has occurred in the system 40, and the control unit 105 from the current sensor 15 that detects the reverse power flow current in the system 40 When the control unit 105 determines that a power failure has occurred in the system 40, the control unit 105 reads the current value immediately before the power failure from the storage unit 104, and stores the current value acquired by the storage unit 104. If the value is not zero, the active detection operation of the detection operation is stopped. [Selection] Figure 1

Description

  The present invention relates to a power conditioner and a power management apparatus.

  2. Description of the Related Art A distributed power supply system that controls a distributed power supply such as a solar power generation device or a power storage device linked to a system is known (see, for example, Patent Document 1).

  In recent years, solar power generation devices have been widely used in ordinary houses. In the future, if EV (Electric Vehicle) and fuel cell devices are spread, it is expected that the use of a plurality of distributed power sources connected to the system will increase in general houses.

  In a house that uses a plurality of distributed power sources connected to the grid, it is desirable that when a power failure occurs, the plurality of distributed power sources can simultaneously operate independently and supply power to the load.

JP 2011-101523 A

  However, several problems are assumed in performing independent operation simultaneously with a plurality of distributed power sources.

  For example, when attempting to operate independently at the same time with the photovoltaic power generation device and the storage battery mounted on the EV, when the remaining capacity of the EV storage battery is small, the photovoltaic power generation device determines that the power is out and stops the output. It is possible to end up. This is because when the power conditioner of the photovoltaic power generation apparatus detects a power failure by active detection operation such as phase shift, the phase shift is detected by controlling the EV power conditioner to reduce the output power. This is because it is determined that a power failure has occurred. As a result, only the EV storage battery will be autonomously operated, and the photovoltaic power generator and the EV storage battery cannot be autonomously operated at the same time. Since a solar power generation device normally detects a power failure by an active detection operation, there is a high possibility that such a situation will occur.

  In addition, it is conceivable to perform control for avoiding the above problem by performing communication between the power conditioner of the photovoltaic power generation apparatus and the power conditioner of the EV. In this case, control is performed with a dedicated command. There is a problem that versatility such as combination between products of other companies is impaired.

  An object of the present invention made in view of such a point is to provide a power conditioner and a power management apparatus that can perform independent operation simultaneously with a plurality of distributed power sources without impairing versatility.

  The power conditioner according to the embodiment of the present invention is used by connecting to a power system in parallel with another power conditioner, and performs power supply to a load connected to the power system by performing a self-sustaining operation at the time of a power failure. A conditioner, a power converter that converts DC power into AC power, a control unit that performs a detection operation for determining whether or not a power failure has occurred in the system, a power purchase current from the system, and the system A storage unit that stores a current value acquired by the control unit from a current sensor that detects a power selling current for a predetermined period, and when the control unit determines that a power failure has occurred in the system, from the storage unit The current value immediately before the power failure is read out, and when the current value is not zero, the active detection operation of the detection operation is stopped.

  In addition, the power management apparatus according to the embodiment of the present invention is used by connecting to a power system in parallel with another power conditioner, and performs self-sustained operation at the time of a power failure and supplies power to a load connected to the power system. A power management device for controlling a power conditioner, wherein a current value is obtained from a current sensor for detecting a power purchase current from the system and a power sale current to the system, and whether or not a power failure occurs in the system is determined. The power conditioner is controlled to execute a detection operation to be determined, and when it is determined that a power failure has occurred in the system, if the current value immediately before the power failure acquired from the current sensor is not zero, the power conditioner Of these detection operations, the active detection operation is stopped.

  According to the power conditioner and the power management apparatus according to the embodiment of the present invention, independent operation can be performed simultaneously with a plurality of distributed power sources without impairing versatility.

1 is a diagram showing a schematic configuration of a distributed power supply system having a power conditioner according to a first embodiment of the present invention. It is a flowchart which shows an example of operation | movement of the power conditioner which concerns on 1st Embodiment of this invention. It is a figure which shows schematic structure of the distributed power supply system which has the power conditioner which concerns on 2nd Embodiment of this invention. It is a figure which shows schematic structure of the distributed power supply system which has the power conditioner which concerns on 3rd Embodiment of this invention. It is a figure which shows schematic structure of the distributed power supply system which has the power management apparatus which concerns on one Embodiment of this invention.

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

<Power conditioner>
[First Embodiment]
FIG. 1 is a diagram showing a schematic configuration of a distributed power supply system 1 having a first power conditioner 100 according to the first embodiment of the present invention. In FIG. 1, a solid line connecting each functional block mainly indicates a power line, and a broken line mainly indicates a communication line or a signal line.

  The distributed power supply system 1 includes a first power conditioner 100, a solar battery 10, a current sensor 15, a second power conditioner 20, a load 25, an EV (electric vehicle) 30, and an auxiliary power supply unit 35. Prepare.

  The first power conditioner 100 and the second power conditioner 20 simultaneously perform self-sustained operation and supply power to a load 25 that is a common load when the system 40 is powered off. At this time, either the first power conditioner 100 or the second power conditioner 20 serves as a reference voltage source, and it is necessary to output a reference AC voltage waveform. In this embodiment, the second power conditioner is used. 20 is a reference voltage source. This is because, generally, the power from the EV30 storage battery has a larger capacity than the solar power generation by the solar battery 10, and the power of the solar power generation has a surface that lacks stability depending on the weather. It is.

  The first power conditioner 100 is used by being connected to the system 40 in parallel with the second power conditioner 20. The first power conditioner 100 converts the DC power supplied from the solar cell 10 into AC power and supplies it to the load 25. Moreover, the 1st power conditioner 100 can also sell the electric power by converting the direct-current power supplied from the solar cell 10 into alternating current power, and making it flow backward to a system | strain (electric power company). When the first power conditioner 100 detects a power failure of the system 40, the first power conditioner 100 detects the output voltage of the second power conditioner 20, performs a self-sustaining operation, and supplies power to the load 25. Details of the configuration and functions of the first inverter 100 will be described later.

  The solar cell 10 generates DC power from sunlight energy and supplies it to the first power conditioner 100. The solar cell 10 is shown as an example of a distributed power source, and may be another type of distributed power source, such as a fuel cell or a storage battery.

  The current sensor 15 detects a power purchase current from the system 40 and a power selling current (reverse power flow current) to the system 40. The current sensor 15 transmits the detected current value to the first power conditioner 100.

  The second power conditioner 20 is used by being connected to the system 40 in parallel with the first power conditioner 100. The second power conditioner 20 performs a self-sustained operation together with the first power conditioner 100 and supplies power to the load 25 when the system 40 has a power failure. In addition, the 2nd power conditioner 20 may perform a self-sustained operation simultaneously with the self-sustained operation of the 1st power conditioner 100, or only the 2nd power conditioner 20 may perform a self-supporting operation. The second power conditioner 20 converts DC power supplied from the storage battery of the EV 30 into AC power and supplies the AC power to the load 25. Further, during the independent operation, the autonomous operation of the first power conditioner 100 is executed by the output voltage waveform output by the second power conditioner 20.

  In addition, the 2nd power conditioner 20 shall not have the function to detect the power failure of the system | strain 40 by active detection operation | movement. This is because, in a distributed power source that does not normally assume power sale, it is possible to determine the presence or absence of a power outage only by a passive detection operation, and therefore it is not necessary to perform an active detection operation that complicates control.

  The second power conditioner 20 includes a power conversion unit 21, a current sensor 22, and a control unit 23.

  The power conversion unit 21 converts DC power supplied from the storage battery of the EV 30 into AC power and supplies the AC power to the load 25. Moreover, the power converter 21 is bidirectional, converts AC power supplied from the system 40 or the first power conditioner 100 into DC power, supplies it to the EV30 storage battery, and charges the EV30 storage battery.

  The current sensor 22 detects a reverse flow current from the power conversion unit 21 to the system 40 and transmits the detected current value to the control unit 23.

  The control unit 23 controls and manages the entire second power conditioner 20, and can be configured by a processor, for example.

  Based on the current value acquired from the current sensor 22, the control unit 23 controls the power conversion unit 21 so that no reverse flow current from the power conversion unit 21 to the grid 40 is generated.

  The control part 23 detects the voltage of the system | strain 40 with the voltage detection line 24, and when a power failure generate | occur | produces in the system | strain 40, it will start independent operation. When performing a self-sustained operation at the time of a power failure, the control unit 23 controls the second power conditioner 20 to be a reference voltage source and to output a reference AC voltage waveform.

  The load 25 is, for example, an electric device connected to the system 40. Although FIG. 1 shows a configuration in which one load 25 is connected to the system 40, the number of loads 25 may be two or more.

  The EV (electric vehicle) 30 includes a storage battery inside. The EV 30 storage battery supplies DC power to the second power conditioner 20 during discharging, and DC power is supplied from the second power conditioner 20 during charging. The EV 30 is shown as an example of a distributed power source, and may be another type of distributed power source, such as a fuel cell.

  The auxiliary power supply unit 35 is a DC voltage source and includes, for example, a storage battery. When the EV 30 is absent and the DC power cannot be supplied from the EV 30 to the second power conditioner 20 due to reasons such as going out of the owner, the auxiliary power supply unit 35 supplies DC power to the second power conditioner 20 instead. Further, when the fuel cell is connected to the second power conditioner 20 instead of the EV 30, the auxiliary power unit 35 is used as a power source for starting the fuel cell when the fuel cell is not generating power at the time of a power failure. be able to. Once the fuel cell is activated, the fuel cell can continue the power generation operation even if the auxiliary power supply unit 35 is stopped.

  Next, the configuration and functions of the first power conditioner 100 will be described in detail. The first power conditioner 100 includes a storage battery 101, a DC / DC conversion unit 102, a power conversion unit 103, a storage unit 104, and a control unit 105.

  The storage battery 101 supplies DC power to the DC / DC converter 102 by discharging. Further, the storage battery 101 is charged with direct-current power supplied from the DC / DC converter 102.

  The DC / DC conversion unit 102 boosts or steps down the voltage of the DC power supplied from the solar cell 10 and / or the storage battery 101 and supplies the voltage to the power conversion unit 103. Further, the DC / DC conversion unit 102 boosts or steps down the voltage of the DC power supplied from the power conversion unit 103 and supplies the voltage to the storage battery 101 to charge the storage battery 101.

  The power conversion unit 103 converts the DC power supplied from the DC / DC conversion unit 102 into AC power and supplies the AC power to the load 25. The power conversion unit 103 can also convert DC power supplied from the solar cell 10 via the DC / DC conversion unit 102 into AC power and reversely flow to the grid (electric power company) to sell power. The power conversion unit 103 is bidirectional, converts AC power supplied from the system 40 or the second power conditioner 20 into DC power, and supplies the DC power to the storage battery 101 via the DC / DC conversion unit 102. The storage battery 101 can be charged.

  The storage unit 104 includes various memories. The storage unit 104 stores the current value acquired from the current sensor 15 by the control unit 105 for a predetermined period. The memory | storage part 104 memorize | stores the electric current value of the predetermined period of about 10-60 seconds, for example, and will erase | eliminate the data of the oldest electric current value, if a new electric current value is acquired.

  The control unit 105 controls and manages the entire first power conditioner 100, and can be configured by a processor, for example.

  Based on the current value acquired from the current sensor 15, the control unit 105 controls the power conversion unit 103 so that the reverse flow current to the grid 40 is not generated when the storage battery 101 is discharged. This is to comply with this request when it is required by the contract with the electric power company that the power generated by the storage battery 101 not flow backward.

  The control unit 105 controls the power conversion unit 103 so as to output a voltage having a waveform equivalent to the waveform of the voltage detected by the voltage detection line 106. Since the first power conditioner 100 does not serve as a reference voltage source even during a power failure of the system 40, the control unit 105 can detect the waveform of the voltage detected by the voltage detection line 106 even during the independent operation during the power failure of the system 40. The power conversion unit 103 is controlled to output a voltage having an equivalent waveform.

  The control unit 105 always acquires a current value from the current sensor 15 and stores the acquired current value in the storage unit 104 for a predetermined period.

  The control unit 105 constantly monitors the power failure of the system 40 by executing a detection operation. This detection operation includes a passive detection operation and an active detection operation. In the passive detection operation, the control unit 105 determines whether there is an abnormality (phase imbalance or sudden frequency change) in the voltage of the system 40 detected by the voltage detection line 106, such as a voltage phase jump detection method or a frequency change rate detection method. It is determined whether or not a power failure has occurred in the grid 40. Further, in the active detection operation, the control unit 105, for example, causes the AC voltage waveform output from the power conversion unit 103 to be phase-shifted with respect to the voltage waveform of the system 40 and outputs the voltage detection line. If the voltage detected by 106 is phase-shifted, it is determined that a power failure has occurred in system 40, and if the voltage detected by voltage detection line 106 is not phase-shifted, it is determined that a power failure has not occurred in system 40. . In this example, the active detection operation method is described with reference to an example of a standard phase shift method in a power conditioner for photovoltaic power generation, but the active detection operation method is not limited to this. The control unit 105 determines whether or not a power failure has occurred in the system 40 by any active detection operation generally known to those skilled in the art, such as an active power fluctuation method, a reactive power fluctuation method, and a load fluctuation method. To do.

(Operation during power failure)
Hereinafter, the operation of the control unit 105 when the system 40 has a power failure will be described. In addition, at the time of the power failure of the system | strain 40, the 1st power conditioner 100 shall perform independent operation substantially simultaneously with the 2nd power conditioner 20, and shall supply electric power to the load 25. FIG. At this time, it is assumed that the second power conditioner 20 is a reference voltage source.

  When the control unit 105 determines that a power failure has occurred in the grid 40 by the passive detection operation or the active detection operation, the control unit 105 controls the power conversion unit 103 to stop the output.

  When the control unit 105 determines that a power failure has occurred, the control unit 105 reads the current value immediately before the power failure acquired from the current sensor 15 from the storage unit 104. When the current value immediately before the power failure is not zero, the control unit 105 shifts the first power conditioner 100 to the “self-sustaining operation mode”. Here, the current value of zero does not mean that the current value is strictly zero, but also includes a current value smaller than a predetermined value (for example, a current value smaller than the error level).

Here, the “self-sustaining operation mode” is a mode in which the control unit 105 performs the following two controls.
(1) When the control unit 105 detects a normal voltage waveform from the voltage detection line 106, the current sensor 15 is broken even if the current value acquired from the current sensor 15 is zero. Do not judge.
(2) The control unit 105 stops detecting a power failure due to the active detection operation.

  The technical meaning of the “self-sustaining operation mode” will be described below.

  In the operation of the conventional power conditioner, when the power conditioner determines that the current sensor that detects the reverse flow current has failed, the reverse flow current that is not permitted by the contract (for example, reverse during the discharge of the power storage device). In order to prevent the (current) from flowing into the grid, the inverter output is stopped. During normal operation, the control unit 105 determines that the current value detected by the current sensor 15 is zero (0 amperes) even though the voltage of the system 40 detected by the voltage detection line 106 or the like is a normal value. In this case, it is determined that the current sensor 15 has failed. However, in the present embodiment, the control unit 105 does not determine that the current sensor 15 has failed even if it detects a zero current value from the current sensor 15 in the self-sustaining operation mode. As a result, during a power failure of the system 40, that is, in a state where the current sensor 15 detects a zero current value, the first power conditioner 100 can perform a self-sustained operation and supply power to the load 25. it can. In the present embodiment, the self-sustained operation of the first power conditioner 100 is performed using an externally supplied AC voltage waveform (in this embodiment, an AC voltage waveform from an EV30 storage battery) as a reference voltage source. Independently, the output of independent operation is not performed.

  Moreover, when the 1st power conditioner 100 and the 2nd power conditioner 20 are performing independent operation and supplying electric power to the load 25, suppose that the 1st power conditioner 100 performs an active detection operation | movement. . In this case, if the remaining capacity of the storage battery of EV30 is small, or if the capacity of the auxiliary power supply unit 35 that is supplying power instead is small when the EV30 is not present, for example, when the power failure detection method is the phase shift method, the first The power conditioner 100 attempts to output a voltage waveform having a phase shifted by 5% with respect to the reference voltage waveform output from the second power conditioner 20 by the active detection operation. At this time, if the second power conditioner 20 has a power capacity capable of obtaining a large output, the phase is corrected so that only the reference voltage waveform remains. However, if the power capacity is small, the voltage waveform of the phase of the first power conditioner 100 remains because the necessary power cannot be obtained due to the lack of capacity, or the output is suppressed due to the lack of capacity. End up. Then, the control unit 105 detects the phase shift, and it is considered that the control unit 105 determines that a power failure has occurred and stops the output of the first power conditioner 100 (phase shift). It is the same in that changes are absorbed by other methods other than the method). Then, the first power conditioner 100 and the second power conditioner 20 cannot perform the self-sustaining operation and supply power to the load 25. However, in this embodiment, the control part 105 stops the detection of the power failure by active detection operation | movement at the time of self-sustained operation mode. As a result, even when the capacity of the EV 30 or the auxiliary power supply unit 35 is small, the active detection is performed when the first power conditioner 100 and the second power conditioner 20 perform independent operation and supply power to the load 25. It can prevent that the output of the 1st power conditioner 100 is stopped by the detection of the power failure by operation | movement.

  When the control unit 105 confirms a normal voltage waveform from the voltage detection line 106 for a predetermined period (300 seconds in the “system interconnection regulation”) after detecting the power failure of the system 40, the control unit 105 resumes the operation of the power conversion unit 103. Then, power is supplied to the load 25.

  In addition, when the control unit 105 shifts to the self-sustaining operation mode, the period for confirming the normal voltage waveform after the power failure is detected is shortened from the period (300 seconds) defined by the “system interconnection regulation”. Control may be switched. Thereby, after the 2nd power conditioner 20 starts an output after the power failure of the system | strain 40, the output of the 1st power conditioner 100 is started in a short time. Moreover, since the time which supplies the electric power to the load 25 by the 2nd power conditioner 20 alone can be shortened by this at the time of a self-sustained operation, the capacity | capacitance of the auxiliary power supply unit 35 can be reduced. Specifically, for example, when shifting to the self-sustained operation mode, if the period for confirming a normal voltage waveform after detection of a power failure remains at a set value of 300 seconds, the generated power of the first power conditioner 100 is used as the load 25. For example, if the load power consumption is 5 kW, the amount of power that must be covered in the period until it can be supplied (300 seconds) is 417 Wh. This amount must be covered by the auxiliary power supply unit 35. However, if the capacity is not sufficient, the power of the auxiliary power supply unit 35 is used up before 300 seconds elapse, and the first power conditioner 100 remains unable to start. End up. However, if the set value for the period to be confirmed is shortened to, for example, 10 seconds, the amount of discharge power to be covered by the auxiliary power supply unit 35 is 1/30 (13.9 Wh), and the first power conditioner 100 is surely Can be started. Further, after the output of the first power conditioner 100 is started, in addition to supplying power to the load 25, the power supply for the reference voltage signal of the second power conditioner 20 is also generated by the first power conditioner 100. You may make it cover with. In this case, even if most of the capacity of the auxiliary power supply unit 35 is discharged, the auxiliary power supply unit 35 can be charged with the generated power output from the first power conditioner 100. It is possible to prepare for a case where the first power conditioner 100 is stopped due to a sudden change in solar radiation.

  When the control unit 105 detects a power purchase current from the system 40 or a power sale current to the system 40 from the current sensor 15 during the operation in the self-sustained operation mode, the system 40 has recovered from the power failure or the circuit is disconnected. It determines with having been cancelled | released, the output of the 1st power conditioner 100 is stopped, self-sustained operation mode is cancelled | released, and it returns to normal operation mode. Thereby, recovery of the system | strain 40 can be detected more rapidly than a passive detection operation | movement, and it can return to a normal driving | operation. Moreover, even if the user makes an erroneous operation such as turning on the interconnection breaker and connecting to the grid during the self-sustaining operation, it can be safely stopped.

  The operation of the first power conditioner 100 according to the first embodiment of the present invention will be described with reference to the flowchart shown in FIG.

  The control unit 105 constantly monitors the current value from the current sensor 15 and stores the current value for a predetermined period in the storage unit 104 (step S101).

  The control unit 105 always determines whether or not a power failure has occurred in the system 40 by the passive detection operation and the active detection operation (step S102).

  When it determines with the power failure having generate | occur | produced in the system | strain 40 (step S102: Yes), the control part 105 reads the electric current value just before detecting a power failure from the memory | storage part 104 (step S103).

  The control unit 105 determines whether or not the current value immediately before detecting a power failure is zero (step S104).

  When the current value immediately before detecting the power failure is zero (step S104: Yes), the control unit 105 determines that the current sensor 15 is suspected of malfunctioning and stops the operation. At this time, even if the state immediately before is a state where there is no load 25, the power consumption for the operation of the first power conditioner 100 performing the determination of this flow or the second power conditioner 20 Since power consumption for operation occurs, the current value does not become zero. Therefore, when the current value is zero, it can be determined that the core of the current sensor 15 is broken or the circuit is broken, the signal line is broken, the connector is broken or disconnected, and the measurement opening / closing part is locked.

  When the current value immediately before detecting the power failure is not zero (step S104: No), the control unit 105 shifts the first power conditioner 100 to the self-sustained operation mode (step S105).

  The control unit 105 confirms the voltage waveform detected by the voltage detection line 106 for a predetermined period (step S106). When the normal voltage waveform can be confirmed for the predetermined period, the control unit 105 operates the power conversion unit 103 to apply power to the load 25. Power supply is started (step S107). Note that the control unit 105 does not start the operation of the power conversion unit 103 if the normal voltage waveform disappears before the predetermined period elapses.

  The control unit 105 monitors the current from the current sensor 15 and always determines whether or not the system 40 has recovered from the power failure (step S108).

  When it determines with the system | strain 40 having recovered | restored from the power failure (step S108: Yes), the control part 105 complete | finishes the independent operation mode of the 1st power conditioner 100 (step S109).

  Thus, according to the present embodiment, when the control unit 105 detects a power failure of the system 40, the control unit 105 reads the current value immediately before the power failure from the storage unit 104, and performs the active detection operation when the current value is not zero. Stop. This allows the first power conditioner 100 and the second power conditioner 20 to perform independent operation at the same time without transmitting / receiving information by a dedicated command to the second power conditioner 20 via a network or the like. Can do. That is, the first power conditioner 100 according to the present embodiment can perform independent operation simultaneously with the second power conditioner 20 without impairing versatility.

[Second Embodiment]
FIG. 3 is a diagram illustrating a schematic configuration of the distributed power supply system 2 including the first power conditioner 100 according to the second embodiment of the present invention. In FIG. 3, the solid lines connecting the functional blocks mainly indicate power lines, and the broken lines mainly indicate communication lines or signal lines.

  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.

  In the second embodiment, the output of the storage battery 101 of the first power conditioner 100 is connected to the input part of the second power conditioner 20, and the storage battery 101 is installed in the first embodiment. It is different from the first embodiment in that it is a substitute for 35.

  By adopting this configuration, even if the auxiliary power supply unit 35 installed in the first embodiment is not installed, the storage battery 101 of the first power conditioner 100 causes a direct current to the second power conditioner 20 when the EV 30 is absent. Electric power can be supplied. Further, when a fuel cell is installed instead of the EV 30, the storage battery 101 can be used as a power source for starting the fuel cell when the fuel cell is not generating power during a power failure.

[Third Embodiment]
FIG. 4 is a diagram illustrating a schematic configuration of the distributed power supply system 3 including the first power conditioner 100 according to the third embodiment of the present invention. In FIG. 4, the solid lines connecting the functional blocks mainly indicate power lines, and the broken lines mainly indicate communication lines or signal lines.

  In the third 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.

  The third embodiment is different from the first embodiment in that the first power conditioner 100 is not supplied with DC power from the solar battery 10 but only supplies the power of the built-in storage battery 101 to the load 25. To do.

  Under the current regulations, it is not allowed to reversely flow the generated power of the power storage device to the grid 40, so that the generated power from the solar cell 10 is not converted as in the first power conditioner 100 in the third embodiment. The configuration often does not have an active detection function. However, if a reverse power flow is recognized in order to reduce frequency fluctuations caused by photovoltaic power generation in the future, an active detection function is installed even in the configuration of the first power conditioner 100 in the third embodiment. It is assumed that the same control as in the first embodiment can be performed.

<Power management device>
FIG. 5 is a diagram illustrating a schematic configuration of the distributed power supply system 4 including the power management apparatus 45 according to the embodiment of the present invention. In FIG. 5, a solid line connecting the functional blocks mainly indicates a power line, and a broken line mainly indicates a communication line or a signal line.

  In the present 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.

  The present embodiment is a first embodiment in that the distributed power supply system 4 has a power management device 45 and the power management device 45 acquires a current value from the current sensor 15 instead of the first power conditioner 100. It differs from the form.

  In the present embodiment, when the power management device 45 determines whether or not to shift the first power conditioner 100 to the self-sustaining operation mode and causes the power management device 45 to transition to the self-sustaining operation mode, the power management device 45 does so. Is transmitted to the control unit 105 of the first power conditioner 100. Since the current sensor 15 can be shared by the power management device 45 and the first power conditioner 100, the number of parts can be reduced.

  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 is a method including steps executed by each component of the apparatus, a method executed by a processor included in the apparatus, a program, or a storage medium storing the program. It should be understood that these can also be realized and are included in the scope of the present invention.

1, 2, 3, 4 Distributed power supply system 10 Solar cell 15 Current sensor 20 Second power conditioner 21 Power conversion unit 22 Current sensor 23 Control unit 24 Voltage detection line 25 Load 30 EV (electric vehicle)
35 Auxiliary power unit 40 System 45 Power management device 100 First power conditioner 101 Storage battery 102 DC / DC conversion unit 103 Power conversion unit 104 Storage unit 105 Control unit 106 Voltage detection line

Claims (5)

A power conditioner that is used in parallel with another power conditioner for the system, and that performs self-sustained operation during a power failure and supplies power to a load connected to the system,
A power converter that converts DC power to AC power;
A control unit that executes a detection operation for determining whether or not a power failure occurs in the system;
A storage unit that stores a current value acquired by the control unit from a current sensor that detects a power purchase current from the system and a power sale current to the system for a predetermined period;
When the control unit determines that a power failure has occurred in the system, the control unit reads the current value immediately before the power failure from the storage unit, and when the current value is not zero, stops the active detection operation among the detection operations. Power conditioner characterized by   2. The power conditioner according to claim 1, wherein when the current value immediately before the power failure read from the storage unit is not zero, the control unit further includes the current even though the voltage value of the system is a normal value. A power conditioner that does not determine that the current sensor has failed even if the current value acquired from the sensor is zero.   The power conditioner according to claim 1 or 2, wherein the control unit determines that a power failure has occurred in the system and stops the operation of the power conversion unit, and then restarts the operation of the power conversion unit. A power conditioner characterized in that the period for confirming a normal voltage waveform is shortened compared to the period specified in the grid connection regulations.   In the power conditioner of any one of Claim 1 to 3, the said control part will determine with the said system | strain having recovered | restored from the power failure, if the electric power purchase current is detected from the said current sensor, and will be in a normal operation mode. A power conditioner that returns. A power management device for controlling a power conditioner that is used in parallel with another power conditioner for a system and that performs self-sustained operation during a power failure and supplies power to a load connected to the system,
Obtain a current value from a current sensor that detects a power purchase current from the system and a power sale current to the system,
Controlling the inverter to perform a detection operation for determining whether or not a power failure has occurred in the system;
When it is determined that a power failure has occurred in the system, the active detection operation of the detection operation of the power conditioner is stopped if the current value immediately before the power failure acquired from the current sensor is not zero. Power management device.

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