JP2008283764A - Power conditioner for dispersed power sources and dispersed power system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power conditioner for dispersed power sources that is capable of outputting single-phase alternating-current power in linkage operation and three-phase alternating-current power in isolated operation. <P>SOLUTION: The power conditioner 20 for dispersed power sources is used to link a dispersed power source 10 to system power supply and includes an inverter 22 having first and second switching elements, third and fourth switching elements, and first and second capacitive elements connected to a direct-current bus in the power conditioner 20 for dispersed power sources. The phase of a driving signal for the first to fourth switching elements is switched between linkage operation and isolated operation. Thus, single-phase alternating-current power is outputted in linkage operation and three-phase alternating-current power is outputted in isolated operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power conditioner for connecting a distributed power source such as a solar cell or a fuel cell to a system power source, and a distributed power system using the power conditioner.

  In recent years, solar cells, fuel cells, wind power generators, etc. have been deployed as distributed power supply devices at the location of power consumers (customers), and the power from these distributed power sources and the grid power supply (commercial power supply) of electric power companies A distributed power supply system that is combined with other power sources to cover the power consumption of power consumers is attracting attention.

  In order to superimpose the power from the distributed power source on the AC power from the system power source and distribute it to the load in the home of the power consumer, it is necessary to link the distributed power source to the system power source. The power from the distributed power source is often direct current power, and even if it is alternating current power, the frequency and voltage are not compatible with the system power source, so it is converted into predetermined alternating current power from the distributed power source, A power conditioner (PCS) that adapts the frequency and voltage to the power from the system power supply is used. The output line of AC power from the inverter is generally connected to the distribution line from the system power supply side in the distribution board provided in the home of the power consumer, and this allows the load to be placed in the home of the power consumer. On the other hand, AC power from the distributed power source and AC power from the system power source are supplied together. The power conditioner is equipped with a chopper circuit, inverter circuit, interconnection reactor, noise filter, etc., and after boosting the input voltage to the required voltage by the chopper circuit, it converts the DC power to AC power using the switching element in the inverter circuit. Output via a connected reactor or noise filter.

  By the way, from the viewpoint of power transmission efficiency, the power grid of electric power companies generally requires single-phase AC power by transmitting three-phase AC power from a three-phase generator to a consumption area via a transmission line or substation. In such a case, the three-phase power is converted into single-phase power at a position immediately before the place where the single-phase AC power is consumed. Therefore, the unit price of electric power is higher for single-phase power than for three-phase power, and when using a distributed power supply linked to the system power supply, use it on the single-phase power side rather than on the three-phase power side. The cost merit becomes larger. Therefore, at present, as a power conditioner for connecting a distributed power supply to a system power supply, one that outputs single-phase AC power is generally used.

  By the way, since distributed power sources such as solar cells and fuel cells can supply power independently, emergency power sources in the event that a disaster such as an earthquake occurs and power outages in the system power source are expected to continue As promising. However, at present, a system that connects a distributed power source to a system power supply generally outputs a single-phase AC power, so it can be used for the purpose of supplying three-phase AC power to a load in the event of a system power failure. Can not. On the other hand, there is a demand for driving a load driven by three-phase AC power, that is, a three-phase load, when the system power supply fails. For example, in a fuel supply station (gas station) that supplies fuel such as gasoline and light oil to road transport vehicles such as trucks, buses, and passenger cars, fuel is supplied to various emergency vehicles even during disasters such as earthquakes. Therefore, in the fuel supply station, even if the power from the distributed power source is supplied to the load driven by single-phase AC power, that is, to the single-phase load at normal time, It is desired that three-phase AC power can be generated with electric power and supplied to a three-phase load. It is also effective to output single-phase AC power, which is usually in high demand during firefighting facilities, hospitals, and apartment buildings. It is desired to output three-phase AC power for supplying power to a pumping pump that is an essential device or a highly important water supply device.

  In addition, in patent 3289418 specification (patent document 1), when the emergency private power generation equipment of three-phase alternating current power is equipped etc., three-phase alternating current power is changed into single-phase alternating current power at the time of a power failure of a system power supply. A configuration for converting and supplying to a load is disclosed. However, in this configuration, three-phase AC power can be obtained even in an emergency, and then single-phase AC power is generated. Three-phase AC power is typically generated from a distributed power source that outputs DC power, such as a solar cell or a fuel cell. Cannot be used when generating phase AC power.

Japanese Patent No. 3553180 (Patent Document 2) discloses a configuration in which three-phase AC power is generated from a DC power source. However, since this configuration does not generate single-phase AC power, it is usually used to generate single-phase AC power linked to the system power supply and to generate three-phase AC power when the system power supply fails. I can't do it.
Japanese Patent No. 3289418 Japanese Patent No. 3553180

  As described above, a distributed power source such as a solar cell or a fuel cell is installed in a place of a power consumer, and these distributed power sources are connected to a system power source to perform a connected operation. A power supply system that supplies single-phase AC power to the load has been put into practical use, but in the event of a power failure of the system power supply, the distributed power supply is disconnected from the system power supply, and three-phase AC power is obtained from the power supply system. I could not.

  Therefore, the present invention uses a distributed power supply conditioner that can output single-phase AC power during grid operation and can output three-phase AC power during independent operation, and this distributed power conditioner. An object is to provide a distributed power supply system.

  In the present invention, in a power conditioner for a distributed power source that connects a distributed power source to a system power source including a single-phase system power source and a three-phase system power source, the first power source connected to the DC bus of the inverter in the power source for the distributed power source. A first leg connected in series with the first and second switching elements; a second leg connected in series with the third and fourth switching elements connected to the DC bus; and a first leg connected to the DC bus. A commercial frequency AC voltage output from the first leg and the second leg during a linked operation in which a distributed power source is linked to a single-phase system power source. The phase of the commercial frequency AC voltage output from the first leg and the second leg is shifted by 60 degrees during the self-sustained operation with the dispersed power source disconnected from the single-phase system power source. Then And to output the three-phase AC voltage from the first leg and the second leg and the capacitor voltage divider.

  According to this power conditioner for a distributed power source, by switching the output voltage phase of the two legs in the inverter during the interconnected operation and the independent operation, the single-phase AC power is output during the interconnected operation, and during the independent operation. Three-phase AC power can be output.

  By the way, in order to obtain two powers of single-phase AC power and three-phase AC power from DC power, it is conceivable to have two different circuits. For example, a full-bridge inverter using two legs can be considered as a circuit for obtaining single-phase AC power from DC power, and three legs are used as a circuit for obtaining three-phase AC power from DC power. A three-phase bridge-type inverter using the above can be considered. However, when these two circuits are provided, the apparatus becomes large, complicated, and expensive.

  However, according to the power conditioner for a distributed power source, since only one inverter equivalent to a full bridge type inverter using two legs is provided, it is possible to suppress an increase in size, complexity, and cost. it can.

  The above-described power conditioner for distributed power supply includes a power failure detection means for detecting a power failure of the system power supply, and a switching control means for switching from the grid operation to the independent operation when the power failure of the system power supply is detected by the power failure detection means. It is preferable to further provide. According to this configuration, when the system power supply fails, switching from the grid operation to the independent operation can be performed autonomously.

  It is preferable that the above-described power conditioner for a distributed power supply further includes power storage means connected between the distributed power supply and the inverter. According to this configuration, it is possible to compensate for the excess or deficiency of the power of the distributed power supply with respect to the output power during the independent operation, and to suppress fluctuations in power flow at the interconnection point during the interconnection operation.

  The distributed power supply system of the present invention is a distributed power supply system connected to a system power supply including a single-phase system power supply and a three-phase system power supply. With na.

  According to this distributed power supply system, since the power conditioner for the distributed power supply described above is provided, single-phase AC power can be output during grid operation, and three-phase AC power can be output during independent operation. , Complexity and high price can be suppressed.

  According to the present invention, a single phase AC power can be output by linking a distributed power supply to a system power supply in a normal state, and a three-phase AC power can be supplied by disconnecting the distributed power supply from the system power supply and operating independently in a power failure of the system power supply. .

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

[First Embodiment]
1 and 2 are circuit diagrams showing configurations of a distributed power supply system and a distributed power supply conditioner according to the first embodiment of the present invention. FIG. 1 shows a state at the time of a connected operation in which a distributed power source is connected to a system power source, and FIG. 2 shows a state at the time of a stand-alone operation in which the distributed power source is disconnected from the system power source. The distributed power supply system 1 illustrated in FIGS. 1 and 2 includes a distributed power supply 10 and a power conditioner 20 for distributed power supply. 1 and 2 show a single-phase system power source and a single-phase load 5 and a three-phase load 6 together with the distributed power supply system 1.

  The distributed power source 10 is a DC power source, and for example, a solar cell or a fuel cell can be suitably applied to the distributed power source 10. Moreover, what distributed the output of a wind power generator, an engine generator, a turbine generator, etc. to the direct current with the converter to the distributed power supply 10 is applicable. The distributed power supply 10 is connected to the power conditioner 20.

  The power conditioner 20 connects the distributed power supply 10 to the system power supply, and converts DC power from the distributed power supply 10 into AC power. For example, the power conditioner 20 connects the distributed power supply 10 to a single-phase system power supply (interconnection operation) during normal operation when the system power supply is operating normally, and converts the DC power into single-phase AC power. Output to phase system power supply and single-phase load 5. On the other hand, at the time of a power failure of the system power supply, the power conditioner 20 disconnects the distributed power supply 10 from the single-phase system power supply (self-sustained operation), converts DC power into three-phase AC power, and outputs it to the three-phase load 6. The power conditioner 20 includes a step-up chopper unit 21, a voltage control unit 21a, a driver unit 21b, an inverter unit 22, an interconnected reactor / noise filter unit 23, circuit breakers 24 and 25, and a voltage monitoring unit 26. The current command value calculation unit 27 and the driver unit 28 are provided.

  The boost chopper unit 21 generates boosted DC power obtained by boosting DC power from the distributed power supply 10. The step-up chopper unit 21 has a switching element, and the switching element is feedback-controlled by the voltage control unit 21a and the driver unit 21b, so that the step-up DC voltage is held substantially constant above the peak value of the system power supply voltage. If the output voltage of the distributed power supply 10 is equal to or higher than the peak value of the system power supply voltage, the boost chopper unit 21, the voltage control unit 21a, and the driver unit 21b may not be used. The step-up chopper unit 21 outputs this step-up DC power to the inverter unit 22.

  The inverter unit 22 converts the boost DC power from the boost chopper unit 21 into single-phase AC power or three-phase AC power. FIG. 3 is a circuit diagram showing a configuration of the inverter unit 22. The inverter unit 22 illustrated in FIG. 3 includes first to fourth switching elements 31 to 34 and first and second capacitive elements 35 and 36. In this embodiment, since IPM (Intelligent Power Module) is used as the first to fourth switching elements 31 to 34, the first to fourth switching elements 31 to 34 have bipolar transistors and recovery diodes. ing.

  The first and second switching elements 31, 32 are connected in series between a pair of DC buses to form a u / r leg (first leg) 37, and the third and fourth switching elements 33, 34. Are connected in series between a pair of DC buses to constitute a v / t leg (second leg) 38. Further, the first and second capacitive elements 35 and 36 are connected in series between a pair of DC buses to constitute a capacitive voltage dividing means 39. The pair of DC buses are connected to the step-up chopper unit 21, and the voltage dividing point o / s between the u / r leg 37, the v / t leg 38, and the first and second capacitive elements 35, 36 is connected to each other. The system reactor / noise filter unit 23 is connected.

  The first to fourth switching elements 31 to 34 are driven by a drive signal from the driver unit 28. Thereby, the inverter part 22 converts direct-current power into single-phase alternating current power, and outputs u-phase alternating current power and v-phase alternating current power from u / r leg 37 and v / t leg 38, respectively, at the time of interconnection operation. . On the other hand, during the self-sustained operation, the inverter unit 22 converts the DC power into the three-phase AC power, and the r-phase AC power and the t-phase from the u / r leg 37, the v / t leg 38, and the voltage dividing point o / s, respectively. AC power and s-phase AC power are output. The frequencies of u-phase AC power, v-phase AC power, r-phase AC power, t-phase AC power, and s-phase AC power are commercial frequencies. Details of the drive signals for driving the first to fourth switching elements 31 to 34 will be described later.

  In addition, as a magnitude | size of the inverter part 22, it is preferable that it is 100 VA or more. Thereby, it is easy to adapt to the output power of the distributed power supply 10 which exists now. Moreover, as a magnitude | size of the inverter part 22, it is preferable that it is 100 kVA or less. Thereby, the cheap switching element which exists now can be used.

  The interconnected reactor / noise filter unit 23 includes a reactor for connecting the system power supply and load to the inverter unit 22, and a noise filter including an inductor, a capacitive element, and the like. The inductor and the interconnected reactor in the noise filter may be shared. The interconnected reactor / noise filter unit 23 is connected to the circuit breakers 24 and 25.

  The circuit breaker 24 connects the inverter unit 22 to the single-phase system power source and the single-phase load 5 during the interconnection operation, and disconnects during the independent operation. For example, the circuit breaker 24 opens and closes based on a power failure detection signal from the voltage monitoring unit (power failure detection means) 26.

  The circuit breaker 25 disconnects the inverter unit 22 and the three-phase load 6 during the interconnection operation and connects during the independent operation. For example, the circuit breaker 25 opens and closes based on a power failure detection signal from the voltage monitoring unit (power failure detection means) 26.

  The voltage monitoring unit 26 monitors the voltage from the system power supply and the voltage from the inverter unit 22. The voltage monitoring unit 26 is mainly intended to monitor the voltage from the system power supply during the interconnected operation, and is mainly intended to monitor the voltage from the inverter unit 22 during the independent operation. The voltage monitoring unit 26 outputs the detected voltage waveform information to the current command value calculation unit 27.

  The current command value calculation unit 27 obtains a current waveform corresponding to the system power supply voltage waveform so as to obtain a high power factor based on the voltage waveform information from the voltage monitoring unit 26 during the interconnection operation, and based on this current waveform. The current command value, which is the current command value of each of the first to fourth switching elements 31 to 34 for obtaining single-phase AC power, is output to the driver unit 28.

  On the other hand, during the independent operation, the current command value calculation unit 27 is a command value corresponding to the reference signal (frequency 50 Hz or 60 Hz) from the internal oscillator and the voltage waveform information from the voltage monitoring unit 26, and the three-phase AC power is The command values of the first to fourth switching elements 31 to 34 for obtaining are output to the driver unit 28. That is, the current command value calculation unit 27 performs duty control (PWM (Pulse Width Modulation) control) of the drive signal so that the output voltage of the inverter unit 22 has a frequency value and a voltage value corresponding to the reference signal during the independent operation. Find the command value for.

  The current command value calculation unit 27 includes a PU (Processing Unit) that performs calculation, a program for causing the PU to execute each process, and first to fourth switching elements 31 to 31 for obtaining single-phase AC power. 34 has a ROM (Read Only Memory) for storing current command value data of each, command value data of each of the first to fourth switching elements 31 to 34 for obtaining three-phase AC power, and the like. With such a configuration, the above-described functions are realized in the current command value calculation unit 27.

  Moreover, the voltage monitoring part 26 and the electric current command value calculating part 27 function as a power failure detection means, and detect the power failure of a system power supply. For example, the voltage monitoring unit 26 and the current command value calculation unit 27 have an isolated operation detection function, and when the change of the voltage phase is detected by periodically changing the current phase, it is determined that the system power supply has failed. . Specifically, the current command value calculation unit 27 periodically changes the current phase, and the voltage monitoring unit 26 monitors the change of the voltage phase. When the system power supply is in operation, the voltage phase is not changed by the power from the system power supply even if the current phase of the inverter unit 22 is changed, but when the system power supply is out of power, the voltage is changed according to the change in the current phase. The phase changes. Thereby, a power failure of the system power supply can be detected. The voltage monitoring unit 26 outputs a power failure detection signal to the current command value calculation unit 27 and the circuit breakers 24 and 25 when detecting a power failure of the system power supply.

  Further, the current command value calculation unit 27 functions as a switching control unit, and based on the power failure detection signal from the voltage monitoring unit 26, the three-phase during the independent operation from the single-phase AC power generation control at the time of the grid connection described above. Switch to AC power generation control autonomously.

  The driver unit 28 supplies a drive signal to the first to fourth switching elements 31 to 34 in the inverter unit 22 based on the command value from the current command value calculation unit 27. FIG. 4 is a vector diagram showing the relationship between the AC voltage phases output by the two legs during the interconnection operation, and FIG. 5 is a vector diagram showing the relationship between the AC voltage phases output by the two legs during the autonomous operation. It is.

  As shown in FIG. 4, the driver unit 28 includes a u / r leg 37 including switching elements 31 and 32 according to the current command value from the current command value calculation unit 27, The AC output voltage of the v / t leg 38 composed of 33 and 34 is driven with a phase difference of 180 ° from each other. In this way, single-phase AC power is generated between the u / r leg 37 and the v / t leg 38. The voltage dividing point o / s of the capacitive elements 35 and 36 is used as a neutral line, but it is not necessarily connected to the system.

  On the other hand, during the self-sustained operation, as shown in FIG. 5, the driver unit 28 includes a u / r leg 37 composed of the switching elements 31 and 32 according to the command value from the current command value calculation unit 27, The v / t leg 38 composed of 33 and 34 is driven with a phase difference of 60 ° from each other. As a result, three-phase AC power is generated between the voltage dividing points o / s of the u / r leg 37, the v / t leg 38, and the capacitive elements 35, 36.

  Thus, according to the power conditioner 20 for distributed power supplies of 1st Embodiment, the phase of the drive signal of the four switching elements 31-34 in the inverter part 22 is switched by the time of a grid operation and a self-sustained operation. Thus, single-phase AC power can be output during the interconnection operation, and three-phase AC power can be output during the independent operation. Moreover, according to the power conditioner 20 for distributed power supplies of 1st Embodiment, when a system power supply interrupts, switching from a grid operation to a self-sustained operation can be performed autonomously.

  Therefore, according to the power conditioner 20 for the distributed power supply of the first embodiment, since only one inverter unit 22 corresponding to a full bridge type inverter using four switching elements is provided, the size and the complexity of the inverter are increased. High price can be suppressed.

  Further, according to the distributed power supply system 1 of the first embodiment, since the power conditioner 20 for distributed power supply described above is provided, single-phase AC power is output during the interconnected operation, and three-phase AC power is output during the independent operation. When the system power supply fails, the switching from the grid operation to the independent operation can be performed autonomously. Moreover, enlargement, complication, and price increase can be suppressed.

[Second Embodiment]
6 and 7 are circuit diagrams showing configurations of a distributed power supply system and a distributed power supply conditioner according to the second embodiment of the present invention. FIG. 6 shows a state at the time of interconnection operation in which the distributed power source is connected to the system power source, and FIG. 7 shows a state at the time of independent operation in which the distributed power source is disconnected from the system power source. The distributed power supply system 1A shown in FIGS. 6 and 7 is different from the first embodiment in that the distributed power supply system 1 includes a distributed power supply power conditioner 20A instead of the distributed power supply power conditioner 20. . The other configuration of the distributed power supply system 1A is the same as that of the distributed power supply system 1.

  The power conditioner 20 </ b> A further includes a power storage device (power storage means) 41, a bidirectional converter 42, and a charge / discharge control unit 43 in the power conditioner 20. Other configurations of the power conditioner 20 </ b> A are the same as those of the power conditioner 20.

  The power storage device 41 compensates for excess or deficiency of the power of the distributed power supply 10 with respect to the output power of the power conditioner 20A. For example, the power storage device 41 supplies insufficient power when the output power of the distributed power supply 10 is smaller than necessary power, and supplies excess power when the output power of the distributed power supply 10 is larger than necessary power. store. As the electricity storage device 41, a secondary battery, an electric double layer capacitor, or the like is preferably used. In addition, a lead storage battery, a nickel metal hydride battery, a nickel cadmium battery, a lithium ion battery, a zinc-air battery, a redox flow battery, a sodium sulfur battery, an electric double layer capacitor, and the like are also applicable as the electricity storage device 41.

  The output power of the electricity storage device 41 is preferably at least 0.1 times the rated output power of the distributed power supply 10. Thereby, the output power compensation effect by the electricity storage device 41 can be sufficiently obtained. Moreover, it is preferable that the output power of the electrical storage device 41 is 10 times or less. Thereby, enlargement and price increase can be suppressed.

  The energy of the electricity storage device 41 is preferably energy that can be held for 10 minutes or more with respect to its own rated power. Thereby, a sufficient backup effect can be obtained. The energy of the electricity storage device 41 is preferably energy that can be held for 10 hours or less with respect to its own rated power. Thereby, enlargement and price increase can be suppressed.

  Bidirectional converter 42 is provided between a node between boost chopper unit 21 and inverter unit 22 and power storage device 41. The bidirectional converter 42 supplies power from the power storage device 41 to the inverter unit 22 when the output voltage of the boost chopper unit 21 is lower than the voltage of the power storage device 41, and the output voltage of the boost chopper unit 21 is stored in the power storage device 41. The power from the boost chopper unit 21 is supplied to the power storage device 41 when the voltage rises above the voltage. The bidirectional converter 42 is controlled by the charge / discharge control unit 43.

  The charge / discharge control unit 43 functions to suppress rapid and excessive charge / discharge of the power storage device 41.

  Also with the distributed power supply conditioner 20A of the second embodiment, the same advantages as the distributed power supply conditioner 20 of the first embodiment can be obtained. Furthermore, according to the power conditioner 20A for the distributed power supply of the second embodiment, by using the power storage device in combination, it is possible to compensate for the excess or deficiency of the power of the distributed power supply relative to the output power during the independent operation, and the interconnection operation Sometimes tidal current fluctuations at the interconnection point can be suppressed.

  Also, the distributed power supply system 1A of the second embodiment includes the above-described distributed power supply power conditioner 20A, so that the same advantages as the distributed power supply system 1 of the first embodiment can be obtained. Furthermore, according to the distributed power supply system 1A of the second embodiment, it is possible to compensate for the excess or deficiency of the power of the distributed power supply relative to the output power during the independent operation, and to suppress the power flow fluctuation at the connection point during the connected operation. Can do.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the distributed power supply power conditioner 20 autonomously performs the interconnection operation and the independent operation, but may be manually performed. In this case, the voltage monitoring unit 26 and the current command value calculation unit 27 do not need to have a power failure detection function.

  Further, the power failure detection means by the voltage monitoring unit 26 and the current command value calculation unit 27 detects a power failure of the system power supply using the isolated operation detection function, but the overvoltage detection function, the low voltage detection function, the high frequency detection function, It is also possible to detect a power failure of the system power supply using various functions such as a low frequency detection function.

  In addition to the isolated operation detection function, the overvoltage detection function, the low voltage detection function, the high frequency detection function, and the low frequency detection function as a power failure detection means, the voltage monitoring unit 26 further includes an independent operation detection function as a protection means. An overvoltage detection function, a low voltage detection function, a high frequency detection function, a low frequency detection function, and the like may be provided. For example, these protection means monitor the voltage at the subsequent stage of the circuit breaker 24 and forcibly stop the generation of the drive signal in the driver unit 28 when the system power supply is disconnected from the system power supply after a power failure. Let

  Further, the voltage monitoring unit 26 may further include a voltage rise suppression function and an RPR (reverse power flow prevention) function. For example, the voltage rise suppression function monitors the voltage at the previous stage of the circuit breaker 24, and when the voltage rises, the current command value calculation unit 27 reduces the current to suppress the voltage rise. The RPR function is for preventing reverse power flow, that is, power supply from the distributed power supply system to the system power supply. Currently, in a distributed power supply system using a distributed power supply other than a solar battery, it is not permitted to sell electric power to an electric power company. Therefore, a distributed power supply system using a distributed power supply other than a solar cell needs to have an RPR function.

  A relay switch may be used in place of the circuit breakers 24 and 25. In this case, it is necessary to provide a relay controller for controlling opening and closing of the relay switch.

  Moreover, in this embodiment, IPM was used as the 1st-4th switching elements 31-34 in the inverter part 22, However Various things are applicable to the 1st-4th switching elements. For example, a bipolar transistor alone may be applied to the first to fourth switching elements, or an FET, an IGBT (Insulated Gate Bipolar Transistor), or the like may be applied.

It is a circuit diagram which shows the structure of the distributed power supply system which concerns on the 1st Embodiment of this invention, and the power conditioner for distributed power supplies, Comprising: It is a circuit diagram which shows the state at the time of interconnection operation. It is a circuit diagram which shows the structure of the distributed power supply system which concerns on the 1st Embodiment of this invention, and the power conditioner for distributed power supplies, Comprising: It is a circuit diagram which shows the state at the time of a self-sustained operation. It is a circuit diagram which shows the structure of the inverter part shown in FIG.1 and FIG.2. It is a vector diagram which shows the relationship of the alternating voltage phase which two legs shown in FIG.1 and FIG.2 outputs, Comprising: It is a vector diagram which shows the relationship at the time of interconnection operation. It is a vector diagram which shows the relationship of the alternating voltage phase which two legs shown in FIG.1 and FIG.2 outputs, Comprising: It is a vector diagram which shows the relationship at the time of a self-sustained operation. It is a circuit diagram which shows the structure of the distributed power supply system which concerns on the 2nd Embodiment of this invention, and the power conditioner for distributed power supplies, Comprising: It is a circuit diagram which shows the state at the time of interconnection operation. It is a circuit diagram which shows the structure of the distributed power supply system which concerns on the 2nd Embodiment of this invention, and the power conditioner for distributed power supplies, Comprising: It is a circuit diagram which shows the state at the time of a self-sustained operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A ... Distributed power supply system, 5 ... Single phase system power supply and single phase load, 6 ... Three-phase load, 10 ... Distributed power supply, 20, 20A ... Power conditioner for distributed power supply, 21 ... Boost chopper part, 21a ... Voltage Control part, 21b ... Driver part, 22 ... Inverter part, 23 ... Interconnection reactor / noise filter part, 24, 25 ... Circuit breaker, 26 ... Voltage monitoring part (power failure detection means, switching control means), 27 ... Current command value Arithmetic unit (power failure detection means, switching control means), 28... Driver part, 31 to 34... First to fourth switching elements, 35 and 36... First and second capacitive elements, 37. First leg), 38... V / t leg (second leg), 39... Capacitance voltage dividing means, 41 .. Electric storage device (electric storage means), 42 .. Bidirectional converter, 43.

Claims (4)

In a power conditioner for a distributed power source that links a distributed power source to a system power source including a single-phase system power source and a three-phase system power source.
A first leg connected in series to the first and second switching elements connected to the DC bus of the inverter in the power conditioner for the distributed power source, and third and fourth switching elements connected to the DC bus A second leg connected in series with each other, and a capacity voltage dividing means connected in series with the first and second capacitive elements connected to the DC bus,
When the distributed power supply is connected to the single-phase system power supply, the operation is performed by inverting the phase of the commercial frequency AC voltage output from the first leg and the second leg by 180 degrees,
At the time of self-sustaining operation in which the distributed power source is disconnected from the single-phase system power source, the phase of the commercial frequency AC voltage output from the first leg and the second leg is shifted by 60 degrees, and the first power source is operated. A power conditioner for a distributed power source, wherein a three-phase AC voltage is output from a leg, the second leg, and the capacitive voltage dividing means. A power failure detection means for detecting a power failure of the system power supply;
When a power failure of the system power supply is detected by the power failure detection means, switching control means for switching from the interconnection operation to the independent operation;
The power conditioner for a distributed power supply according to claim 1, further comprising:   The power conditioner for a distributed power supply according to claim 1 or 2, further comprising power storage means connected between the distributed power supply and the inverter. In a distributed power supply system linked to a system power supply including a single-phase system power supply and a three-phase system power supply,
Distributed power supply,
The power conditioner for a distributed power source according to any one of claims 1 to 3, wherein the distributed power source is linked to the system power source.
A distributed power supply system.

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