JP2014230386A - Power conditioner and distributed system with power conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conditioner included in a distributed system capable of transferring a synchronizing signal to numerous power conditioners.SOLUTION: A power conditioner 2is configured to convert DC power into AC power which can be interlocked to a power system, and output the AC power, and comprises: a communication interface 24A for exchanging a synchronizing signal with a power conditioner 2via a transmission line 16; a communication interface 24B for exchanging a synchronizing signal with a power conditioner 2via a transmission line 16; a synchronizing signal monitor part 23d for monitoring the synchronizing signal received by the communication interface 24A; and a stop part 23c for stopping output of the AC power when the synchronizing signal being monitored by the synchronizing signal monitor part 23d is eliminated. When the communication interface 24A receives the synchronizing signal, the communication interface 24B transmits the synchronizing signal at a predetermined level regardless of processing executed by the synchronizing signal monitor part 23d and the stop part 23c.

Description

  The present invention relates to a power conditioner that can be connected to an electric power system and a distributed system including the power conditioner.

  A power conditioner that can be connected to an electric power system is required to stop operation immediately when an isolated operation is detected. For this purpose, there is a distributed system using a synchronization line (for example, Patent Document 1). In this distributed system, as shown in FIG. 6, the plurality of power conditioners 102 respectively connected to the solar module 103 are connected by a transmission line 116 in addition to the power line 111. In this system, one of the plurality of power conditioners 102 serves as a master unit, and a synchronization signal is transmitted to a power conditioner 102 (slave unit) other than the master unit. Since the transmission of the synchronization signal is stopped when the power conditioner 102 of the parent device detects the single operation, all the power conditioners 102 can stop the power output to the power system 114.

Japanese Patent No. 3028205

  However, in the system of Patent Document 1, each power conditioner 102 is connected to one transmission line 116. Therefore, the number of power conditioners 102 that can be connected to the transmission line 116 is limited.

  Therefore, an object of the present invention is to provide a distributed system that enables transmission of a synchronization signal to a huge number of power conditioners, and a power conditioner thereof.

  In order to achieve the above object, a power conditioner according to one configuration of the present invention is a power conditioner that converts DC power into AC power that can be linked to a power system and outputs the AC power. A first communication interface that transmits and receives a synchronization signal having a frequency corresponding to the frequency of the AC power to another power conditioner, and a frequency of the AC power via a second transmission line. A second communication interface that transmits and receives a synchronization signal having a corresponding frequency to another one of the power conditioners; and a synchronization signal monitoring unit that monitors the synchronization signal received by one of the first and second communication interfaces; A stop unit that stops the output of the AC power when there is no synchronization signal monitored by the synchronization signal monitoring unit, and the first and second communications When one of the interfaces receives the synchronization signal, the other of the first and second communication interfaces transmits the synchronization signal at a predetermined level regardless of the processing executed by the synchronization signal monitoring unit and the stopping unit. .

  According to this configuration, since each transmission line connecting each power conditioner is separate, even if the number of power conditioners connected to the transmission line is limited, it is connected in series without being affected by this. You can increase the number of inverters. In addition, when one communication interface receives a signal, the other communication interface transmits a signal regardless of the processing executed by the synchronization signal monitoring unit and the stopping unit, so that almost no signal delay occurs in this power conditioner. do not do. Further, since the other communication interface transmits the synchronization signal at a predetermined level, the synchronization signal attenuated by the transmission line is recovered to the predetermined level and transmitted. Therefore, even if the number of power conditioners connected in series is large, the synchronization signal does not attenuate as a whole.

  In addition, since the output of AC power is stopped when there is no synchronization signal monitored by the synchronization signal monitoring unit, only the transmission / reception of the synchronization signal is stopped for the situation where the power output to the power system must be stopped. It can be dealt with promptly.

  Here, the “synchronization signal having a frequency corresponding to the frequency of the AC power” is a periodic signal having a constant frequency, and preferably has the same frequency as the frequency of the AC power.

  A distributed system according to one configuration of the present invention includes at least the power conditioner, the other one power conditioner, and the further another power conditioner. According to this configuration, the inverters are connected in series, and the synchronization signals are sequentially transmitted through the separate transmission lines.

  In a preferred embodiment, one of the power conditioners included in the distributed system functions as a master unit, and the power conditioner functioning as the master unit is a synchronization signal generation unit that generates the synchronization signal. When the occurrence of a serious abnormality is detected, a synchronization signal generation unit that stops the generation of the synchronization signal is provided. According to this, when the occurrence of a serious abnormality is detected, the power conditioner of the master unit stops generating the synchronization signal, and each power conditioner connected in series in the distributed system sequentially receives the synchronization signal. In parallel with this transmission, stop processing is executed in each power conditioner, so that all power conditioners connected in series can quickly stop power output to the power system.

  Here, the “occurrence of a serious abnormality” includes an isolated operation and a ground fault overvoltage. In addition to these, the situation where the power output to the power system must be stopped corresponds to “a serious abnormality”.

  According to the distributed system according to the present invention, since the transmission lines connecting the power conditioners are separate, there is no limit to the number of power conditioners connected in series, and there is almost no signal delay in each power conditioner. In addition, since the synchronization signal is not attenuated as a whole in the series connection of the power conditioners, the synchronization signal can be transmitted to a large number of power conditioners.

1 is a schematic block diagram of a distributed system according to a first embodiment of the present invention. FIG. 2 is a schematic block diagram of a power conditioner that functions as a parent device in the distributed system of FIG. 1. It is a schematic block diagram of the power conditioner which functions as a subunit | mobile_unit in the distributed system of FIG. (A) is a wave form diagram which shows a system voltage signal, (b) is a wave form diagram which shows a synchronizing signal, (c) is a figure which shows the case where there is no signal. It is a schematic block diagram of the distribution system concerning the 2nd Embodiment of this invention. It is a schematic block diagram of the conventional distributed system.

Hereinafter, a distributed system according to a first embodiment of the present invention will be described with reference to the drawings.
A distributed system 1 according to the present embodiment illustrated in FIG. 1 includes a plurality of power conditioners 2. Each power conditioner 2 is connected to one or more solar cell modules 3. For simplification, a configuration in which only one solar cell module 3 is connected to each power conditioner 2 is illustrated.

  The distributed system 1 includes a plurality of power conditioner groups 20, and each power conditioner group 20 includes a plurality of power conditioners 2. The power conditioners 2 included in the power conditioner group 20 are connected in series by the power line 11 to form a series connection for the power of the plurality of power conditioners 2. These power conditioner groups 20 are connected to the current collection box 12 in parallel. Therefore, the current collection box 12 collects AC power output from all the power conditioners 2 constituting all the power conditioner groups 20. The current collection box 12 is connected to the power system 14 via the circuit breaker 13.

All the power conditioners 2 of the distributed system 1 are communicatively connected in the form of a jumper wiring. That is, a certain power conditioner 2 is connected to another power conditioner 2 by a transmission line (communication cable) 16 _{i and} is further connected to another power conditioner 2 by a separate transmission line 16 _i. Connected by ₊₁ . The terminal power conditioners 2 ₁ and 2 _n are connected to only one power conditioner 2 by transmission lines 16 ₁ and 16 _n−1 .

Of all these power conditioners 2, one power conditioner 2 functions as a parent device, and the other power conditioners 2 function as child devices. Which power conditioner 2 functions as a parent device may be determined by any standard. For example, _one of the power conditioners 2 ₁ and 2 _n at both ends may function as the master unit. In the present embodiment, a power conditioner 2 ₁ of one end, of the power conditioner 2 of one power conditioner group 20, most collector boxes power conditioner 2 ₁ close to 12 as a parent device Function. It should be noted that which power conditioner 2 is the parent device is not absolute and may be changed while the distributed system 1 is in operation.

These transmission lines 16, while each power conditioner 2 is operating normally, the synchronization signal comprising a square wave having the same period as the sinusoidal line voltage, a power conditioner 2 ₁ functioning as a master unit Generated and transmitted. Therefore, for example, power conditioner when conditioner 2 _i and the transmission line 16 _i between the power conditioner 2 _{i + 1} is disconnected, distal of the power to the power conditioner 2 ₁ of the main unit than the transmission lines 16 _i Conditioners 2 _{i + 1} to 2 _n do not receive the synchronization signal. The power conditioners 2 _{i + 1} to 2 _n that have stopped receiving the synchronization signal stop power output as described later.

  Thus, since the transmission line 16 is for transmitting a synchronization signal, a management unit (not shown) for acquiring a log of each power conditioner 2 and monitoring each state and each power conditioner 2 A communication cable separate from the transmission line 16 is used for data communication with the communication line 16.

Figure 2 illustrates a power conditioner 2 ₁ functioning as a master unit.
The power conditioner 2 _1, (not shown) DC / DC converter for boosting DC power output from the solar cell module 3, and an inverter 21 for converting the DC power boosted to AC power. Thereby, the power conditioner 2 outputs alternating current power. However, a DC / DC converter (not shown) may be omitted. In the power conditioner 2, an opening / closing means 22 such as an electromagnetic contactor is provided at a portion for supplying the output of the inverter 21 to the power line 11.

Power conditioner 2 ₁ functioning as a master unit has a master unit control means 23A composed of a microcomputer. Base unit control means 23A includes an abnormality determination unit 23a, a synchronization signal generation unit 23b, and a stop unit 23c.

  The abnormality determination unit 23a determines the occurrence of a serious abnormality. Serious abnormalities include islanding detection and ground fault overvoltage. The isolated operation is detected by, for example, an isolated operation detecting means (not shown) in the control means 23A. Any known method may be used for detecting the islanding operation. The ground fault overvoltage is detected by, for example, a ground fault overvoltage detection device (not shown) provided separately from each power conditioner 2. Any known method may be used to detect the ground fault overvoltage. When an isolated operation or a ground fault overvoltage is detected, the abnormality determination unit 23a is notified that an isolated operation or a ground fault overvoltage has been detected. If the abnormality determination unit 23a receives this notification and determines that a serious abnormality has occurred, the abnormality determination unit 23a notifies the synchronization signal generation unit 23b and the stop unit 23c accordingly.

Power conditioner 2 ₁ functioning as a master device also comprises a communication interface 24 insulated circuit 25 and connected thereto. In this embodiment, the communication interface 24 includes a transceiver that implements the RS485 protocol. The transceiver 24 is connected to _one transmission line 161 and includes a transmitter 24a and a receiver 24b. The transmission line 16 is made of, for example, a twisted pair cable or a coaxial cable. The transmitter 24 a sends a voltage waveform having a predetermined size to the transmission line 16. The receiver 24 b receives a voltage waveform from the transmission line 16. Insulating circuit 25, for example, a photocoupler electrically insulates the connected transceiver 24 from the other construction requirements of the power conditioner 2 _1. The insulating circuit 25 may be built in the transceiver 24.

The synchronization signal generator 23b has the same cycle as that of the sine wave of the system voltage shown in FIG. 4A unless it receives a notification that a serious abnormality has occurred from the abnormality determiner 23a. Is generated and sent to the communication interface 24. Transmitter 24a of the communication interface 24, by applying a voltage waveform corresponding to the period of the received square wave to the transmission line 16 _1, transmits a synchronization signal to the power conditioner 2 ₂ adjacent through the transmission line 16 ₁ . When the synchronization signal generation unit 23b receives a notification from the abnormality determination unit 23a that a serious abnormality has occurred, the synchronization signal generation unit 23b notifies the communication interface 24 of a command to turn off the synchronization signal. Transmitter 24a of the communication interface 24, in response to this notice, as shown in FIG. 4 (c), no voltage is applied to the waveform to the transmission line 16 _1. That is, the synchronization signal transmitted to the adjacent power conditioner 2 ₂ via the transmission line 16 ₁ is stopped.

  When the stopping unit 23c receives a notification from the abnormality determining unit 23a that a serious abnormality has occurred, the stopping unit 23c stops the inverter 21 and opens the opening / closing means 22 to output power from the power conditioner 2 to the power line 11. Stop.

In this embodiment, the power conditioner 21 in FIG. 1 that functions as the master unit has _one adjacent power conditioner 2 ₂ and transmits a synchronization signal to this power conditioner 2 _2. The synchronization signal is not received from the power conditioner 2. For this reason, only one set of the communication interface 24 and the insulating circuit 25 may be provided, but a plurality of sets may be provided.

FIG. 3 shows one of the power conditioners 2 _{i that} functions as a slave unit. Note that the power conditioner 2 ₁ same components and which functions as a master unit shown in FIG. 2, the description thereof is omitted denoted by the same reference numerals in FIG.

The power conditioner 2 _i that functions as a slave unit includes first and second communication interfaces 24A and 24B, and two insulating circuits 25 and 25 respectively connected thereto. Each of the first and second communication interfaces 24A and 24B has the same configuration as the communication interface 24 shown in FIG. Therefore, the power conditioner 2 _i functioning as the slave unit, so that the sets of power conditioner 2 communication interface 24 provided in the ₁ and the insulating circuit 25 which functions as a master unit is provided with two pairs .

The power conditioner 2 _i functioning as a slave unit has a slave unit control means 23B composed of a microcomputer. The slave control means 23B includes a stop unit 23c and a synchronization signal monitoring unit 23d. The synchronization signal monitoring unit 23d receives and monitors the voltage waveform of the transmission line 16 _i-1 received by the receiver 24b of the first communication interface 24A via the insulation circuit 25. When a synchronization signal composed of a periodic square wave is received, it is determined that no abnormality has occurred outside, whereas the receiver 24b of the first communication interface 24A does not receive any signal. If no more signals are received, it is determined that some abnormality has occurred outside the power conditioner 2 _i .

The slave unit control means 23B may be provided with an independent operation detection means (not shown) and other means for detecting a serious abnormality in the interior. In this case, the slave unit control means 23B configures a normal flag on a memory (not shown), the default value of this normal flag is turned on, and is turned off when a serious abnormality is detected in the power conditioner 2 _i itself. Switch.

When the synchronization signal monitoring unit 23d determines that some abnormality has occurred outside the power conditioner 2 _i due to the absence of the synchronization signal being monitored, or the power conditioner 2 _i itself When a serious abnormality is detected, the inverter 21 is stopped and the opening / closing means 22 is opened to stop the power output from the power conditioner 2 to the power line 11.

In addition to the first and second communication interfaces 24A and 24B and the two isolation circuits 25 and 25 respectively connected thereto, the power conditioner 2 _i functioning as a slave has an AND logic gate 26. .

The voltage waveform received from the transmission line 16 _{i-1 by} the receiver 24b of the first communication interface 24A is input to the slave unit control means 23B and also to the AND logic gate 26. The value of the normal flag is also input to the AND logic gate 26 from the slave control unit 23B. Therefore, when the normal flag is on, that is, when no abnormality is detected inside or outside the power conditioner 2 _i , the receiver 24 b of the first communication interface 24 A is connected to the transmission line 16 at the output of the AND logic gate 26. _The voltage waveform received from _i-1 appears.

The output of the AND logic gate 26 is input to the transmitter 24a of the second communication interface 24B via the isolation circuit 25. The transmitter 24a applies a voltage waveform corresponding to the input transmission line 16 _i. The voltage value of this voltage waveform has a predetermined magnitude, and is the same magnitude in all the power conditioners 2. For this reason, the receiver 24b of the first communication interface 24A receives the square wave of FIG. 4B having the same period as the sine wave of the system voltage, and detects a serious abnormality in the power conditioner 2 itself. Otherwise, the transmitter 24a of the second communication interface 24B applies a square wave having a predetermined voltage value to the transmission line 16 _i having the same period as the sine wave of the system voltage. In contrast, when the receiver 24b of the first communication interface 24A does not receive a signal from the transmission line 16 _i-1, the transmitter 24a of the second communication interface 24B has a signal to the transmission line 16 _i Not transmitted (illustrated in FIG. 4C). Further, even if the receiver 24b of the first communication interface 24A receives the square wave of FIG. 4B having the same period as the sine wave of the system voltage, if the normal flag is off, the second communication interface The transmitter 24a of 24B does not transmit a signal to the transmission line 16 _i (illustrated in FIG. 4C).

As described above, in the power conditioner 2 _i functioning as the slave unit, the first communication interface 24A receives the signal from the transmission line 16 _i-1 and then the second communication interface 24B is connected via the transmission line 16 _i. Until the signal is transmitted, it only passes through the insulating circuit 25, the AND logic gate 26, and the insulating circuit 25. Therefore, the signal received from the transmission line 16 _i-1 is processed by the control means 23B and the transmission line 16 _i is processed. The processing time in the power conditioner 2 _i is extremely short as compared with the case of sending to the power source.

Although power conditioner 2 _i functioning as a slave unit of the power conditioner 2 ₁ and 3 which functions as a master unit of Figure 2 is shown as a different configuration, each power conditioner 2 includes both components It is preferable that it can function as both the master unit and the slave unit.

The operation of the distributed system 1 will be described with reference to FIG.
At normal time when no abnormality has occurred, the power conditioner 2 ₁ functioning as a base unit generates a synchronization signal by the synchronization signal generator 23b (FIG. 2) and powers the adjacent synchronization signal via the transmission line 16 _1. and it sends it to the conditioner 2 _2. In the power conditioner 2 _{2 that} has received this synchronization signal, if the power conditioner 2 itself does not detect the occurrence of a serious abnormality, the synchronization signal is sent to the opposite side of the power conditioner 2 ₁ that functions as the master unit. To the adjacent power conditioner 2 ₃ through the transmission line 16 ₂ . Similarly, the synchronization signal is sequentially transmitted between the power conditioners 2, and the terminal power conditioner _2n receives the synchronization signal.

Note that in this terminal power conditioner 2 _n , the first communication interface 24A in FIG. 3 receives the synchronization signal, and the synchronization signal monitoring unit 23d determines that some abnormality has occurred outside. It is the same as the power conditioners 2 ₂ to 2 _n-1 (FIG. 1) that function as a slave unit. However, it differs from the power conditioners 2 ₂ to 2 _n-1 (FIG. 1) functioning as other slave units in that a synchronization signal is not sent from the second communication interface 24B to the transmission line 16.

  The synchronization signal transmitted between the inverters 2 is attenuated on the transmission line 16. However, since the transmitter 24a of the second communication interface 24B of each power conditioner 2 applies a predetermined voltage value to the transmission line 16, the synchronization signal attenuated on the transmission line 16 is predetermined by each power conditioner 2. Recover to value. As described above, the number of power conditioners 2 connected to each other by the crossover wiring is not limited from the viewpoint of attenuation of the synchronization signal.

Each power conditioner 2 requires a predetermined time from receiving the synchronization signal from the transmission line 16 to sending the synchronization signal to the transmission line 16. However, from when the first communication interface 24A of the power conditioner 2 receives a signal from the transmission line 16 until it transmits a signal from the second communication interface 24B, the isolation circuit 25, the AND logic gate 26, and the isolation circuit Therefore, the processing time in the power conditioner 2 _i is extremely short compared with the case where the signal received from the transmission line 16 is processed by the control means 23B and sent to the transmission line 16. For this reason, since the plurality of power conditioners 2 sequentially process the synchronization signals, it takes time to transmit the synchronization signals as many as the number of power conditioners 2 in the distributed system 1. Propagation time. For example, even if 1000 power conditioners 2 are installed in the distributed system 1, if the processing time in each power conditioner 2 is about 3 μs, for example, the total propagation time of the distributed system 1 is 3 seconds. is there.

Returning to FIG. 1, when the power conditioner 2 ₁ functioning as a master unit detects a serious abnormality such as a single operation or earth fault over voltage, the power conditioner 2 ₁ adjacent to each other via a transmission line 16 Power It stops transmitting the synchronization signal to the conditioner 2 _2. In the power conditioner 2 ₂ no longer receives a synchronization signal, stops the transmission of the synchronization signal to the adjacent power conditioner 2 _3. Similarly, the stop of the synchronization signal is sequentially transmitted between the power conditioners 2, and the terminal power conditioner _2n does not receive the synchronization signal. Note that the termination power conditioner 2 _n does not receive the synchronization signal, so that the synchronization signal monitoring unit 23d of the slave unit control unit 23B in FIG. Although the output of the unit 23c is stopped, since no transmission line is connected to the second communication interface 24B, the power conditioner 2 _n does not have a synchronization signal being transmitted to be stopped.

  As described above, when a serious abnormality such as an isolated operation or a ground fault overvoltage occurs in the distributed system 1 of FIG. 1, power output from all the power conditioners 2 connected to the grid is stopped.

Since the processing time in each power conditioner 2 is extremely short as described above, the time required for propagation of the synchronization signal is generally within an allowable range even in the distributed system 1 as a whole. For example, if the processing time in each power conditioner 2 is about 3 μs, the total propagation time of the distributed system 1 is 3 seconds when there are 1000 power conditioners 2 in the distributed system 1. When required about 0.1 seconds to 2 stops processing until all of the power conditioner 2 to complete the stop processing power conditioner 2 ₁ functioning as a parent machine from the detection of such isolated operation and local fault over voltage Takes less than 4 seconds.

When abnormality is resolved, sync signal generation means 23b of the power conditioner 2 ₁ of Figure 2 that functions as a master unit generates the re-synchronization signals, and transmits all the power conditioner 2 via the transmission line 16 ₁ . All of the power conditioner 2, which has received the power conditioner 2 ₁ and a synchronizing signal of the parent device that generated the synchronization signal is an inverter 21 is activated while closing the closing means 22 to output again power to the power line 11 .

  Next, a distributed system according to a second embodiment of the present invention will be described with reference to FIG. However, the difference between the second embodiment and the first embodiment will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.

Also in the distributed system 1A of the present embodiment, a plurality of power conditioner groups 20 are connected to the current collection box 12 in parallel as in the first embodiment. As for the communication connection in the form of the jumper wiring, not all the power conditioners 2 are connected in series as in the first embodiment, but a series connection by the jumper wiring is configured for each power conditioner group 20. . Specifically, the distributed system 1A includes a first power conditioner group 20a including a plurality of power conditioners 2 ₁₁ to _{21 1} including a power conditioner 2 ₁₁ that functions as a master unit, and a plurality of power conditioners 2. _A second power conditioner group 20b composed of ₂₁ to _{22 m} and a third power conditioner group 20c composed of a plurality of power conditioners 2 ₃₁ to 2 _3n are provided. In addition, although the number of the power conditioner groups 20 in this embodiment is 3, it may be any number.

In the present embodiment, one of the power conditioner 2 ₂₁ of the second power conditioner group 20b acts as a bridge between the first power conditioner groups 20a and the third power conditioner group 20c. That is, the power conditioner 2 ₂₁ is connected by a transmission line 16 to the power conditioner 2 ₂₂ adjacent the second power conditioner group 20b belonging to the same group, the parent of the first power conditioner group 20a They are connected by respective transmission lines 16 to the power conditioner 2 ₃₁ with power conditioner 2 ₁₁ and the third power conditioner group 20c is machine. The power conditioner 2 ₂₁ serving as the bridge, a communication interface 24 (FIG. 3) are three provided, the synchronization signal received from the power conditioner 2 ₁₁ is a master unit by the first communication interface 24A (FIG. 3) Are transmitted from the two second communication interfaces 24B (FIG. 3) to the connected power conditioners 2 ₂₂ and 2 ₃₁ .

The power conditioner 2 _{11 as the} master unit includes at least one second communication interface 24B (FIG. 3), and transmits a synchronization signal to two adjacent power conditioners 2 ₁₂ and 2 ₂₁ .

Thus, according to this embodiment, since communication connection is comprised corresponding to the connection by a power line, the number of power conditioners 2 connected in series can be reduced. Therefore, when the power conditioner 2 that functions as a slave unit detects an abnormality in the inside thereof, a power conditioner 2 communicatively connected in series to the distal side of the power conditioner 2 ₁₁ which functions as a master unit However, the number of power conditioners 2 is smaller than when all the power conditioners 2 are connected in series. Therefore, it is possible to prevent even the power conditioner 2 that does not need to be stopped.

  As described above, according to the distributed system of the present invention, since the transmission lines connecting the power conditioners are separate from each other, the number of power conditioners connected in series is not limited, and there is almost no signal delay in each power conditioner. In addition, since the synchronization signal is not attenuated as a whole in the series connection of the power conditioners, the synchronization signal can be transmitted to a large number of power conditioners.

  In each of the above embodiments, the transmission line has been described as an electric line. However, the transmission line is not limited to an electric line, and any transmission line can be used as long as it can transmit a synchronization signal. For example, the transmission line may be an optical fiber.

  In addition, the communication interface has been described as implementing the RS485 protocol, but the communication interface is not limited to this and may be composed of any protocol. However, it preferably comprises a serial communication protocol.

Furthermore, although a single operation and a ground fault overvoltage were mentioned as a serious abnormality, it is not necessarily limited to these.
Moreover, in the said embodiment, although the signal which the synchronous signal generation part 23b of FIG. 2 produces | generates shall have the same frequency as alternating current power like FIG. 4 (a) and (b), it has a different frequency. It may be a thing.

2 Power conditioner 16 Transmission line 23c Stop unit 23d Synchronization signal monitoring unit 24 Communication interface

Claims (3)

A power conditioner that converts DC power into AC power that can be connected to the power system and outputs the AC power.
A first communication interface that transmits / receives a synchronization signal having a frequency corresponding to the frequency of the AC power to / from another power conditioner via a first transmission line;
A second communication interface for transmitting and receiving a synchronization signal having a frequency corresponding to the frequency of the AC power to the other one power conditioner via a second transmission line;
A synchronization signal monitoring unit that monitors a synchronization signal received by one of the first and second communication interfaces;
When there is no synchronization signal monitored by the synchronization signal monitoring unit, a stop unit for stopping the output of the AC power,
When one of the first and second communication interfaces receives a synchronization signal, the other of the first and second communication interfaces is predetermined regardless of the processing executed by the synchronization signal monitoring unit and the stop unit. A power conditioner that sends a sync signal at the level of.   A distributed system, comprising at least the power conditioner according to claim 1, the other power conditioner, and the other power conditioner. The distributed system according to claim 2,
One of the power conditioners included in the distributed system functions as a master unit, and the power conditioner functioning as the master unit is
A distributed system, comprising: a synchronization signal generation unit that generates the synchronization signal, and stops generation of the synchronization signal when occurrence of a serious abnormality is detected.

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