JP2021040458A - Power conversion device and system interconnection system - Google Patents

Abstract

To provide technology which can supply power from any of a DC power supply and an AC power supply in a power conversion device and simplify a device configuration.SOLUTION: A power conversion device comprises: a circuit which connects a DC power supply connection part with an AC power supply connection part and in which an inverter part is arranged; a circuit which branches from between the AC power supply connection part and the inverter part to be connected with a control power supply part; a first relay part which blocks the inverter part and the AC power supply connection part when the inverter part is in a stop state; and a second relay part which switchably connects an inverter side power supply line branching from between the inverter part and the first relay part and an AC power supply side power supply line branching from between the first relay part and the AC power supply connection part with the control power supply part, connects the inverter side power supply line with the control power supply part when the inverter part is in an operation state, and connects the AC power supply side power supply line with the control power supply part when the inverter part is in the stop state.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power converter and a grid interconnection system.

Conventionally, a power conditioner for connecting a power generation facility used for a power generation system equipped with a power generation facility such as a solar panel and a commercial power system (hereinafter, also simply referred to as a system) has been known. Further, as such a power conditioner, a DC output unit for a storage battery is provided, the storage battery is charged by electric power from a power generation facility or a system, and the electric power charged in the storage battery is discharged and used. (See, for example, Patent Document 1).

Then, in such a power conditioner, if the storage battery continues to be discharged due to a power failure, for example, and the storage battery becomes over-discharged, only the power for recovery is left in the storage battery. The process of stopping the power supply to the power conditioner is performed. As a result, the power supply to the control power supply that supplies power to the control unit of the power conditioner is cut off, and the power conditioner is stopped. After that, when the power supply from the grid is restored, power is supplied to the control power supply, the power conditioner is restored, and charging of the storage battery is also started.

Japanese Unexamined Patent Publication No. 2003-189477

By the way, as described above, when the power conditioner is supplied with power from the grid to recover, the power conditioner is supplied with power from the storage battery (or power generation equipment) to the control power supply, and the grid (other AC power supply). ) Requires two types of power supply circuits that supply power to the control power supply.

For this reason, it becomes necessary to arrange a noise filter, an insulated power supply (insulated converter), and a rectifier for each circuit, and there is a problem that the device becomes large and costly.

The present invention has been made in view of the above circumstances, and in a power conversion device, the control unit that controls the device can be supplied with power from either a DC power supply or an AC power supply. At the same time, it is an object of the present invention to provide a technique capable of simplifying the device configuration.

In order to achieve the above object, the power conversion device according to the present invention is
DC power supply connection connected to DC power supply and
The AC power connection connected to the AC power and the AC power connection
Inverter part and
Control unit and
A control power supply unit that supplies power to the control unit,
A first circuit that connects the DC power supply connection unit and the AC power supply connection unit and arranges the inverter unit, and
In the first circuit, it is arranged between the inverter unit and the AC power supply connection unit, and when the inverter unit is in a stopped state, the connection between the inverter unit and the AC power supply connection unit is opened. 1 relay part and
A second circuit that branches from between the DC power supply connection unit and the inverter unit and transmits DC power to the control power supply unit.
A first diode section arranged in the second circuit and having the control power supply section on the downstream side,
A third circuit that branches from between the AC power connection unit and the inverter unit and transmits AC power to the control power supply unit.
An inverter-side power supply line that is arranged in the third circuit and branches from between the inverter and the first relay, and an AC power supply that branches from between the first relay and the AC power connection. The second relay unit, which connects the power supply line to the control power supply unit side in a switchable manner,
In the third circuit, a second diode section arranged between the second relay section and the control power supply section and having the control power supply section on the downstream side and a second diode section.
A DC / DC converter that is shared by the second circuit and the third circuit and that transforms the electric power transmitted to the second circuit and the third circuit to a predetermined voltage and supplies the power to the control power supply unit. Have and
The control unit
When the inverter unit is in an operating state, the second relay unit is controlled so that the power supply line on the inverter side and the second diode unit are connected to each other.
When the inverter unit is in the stopped state, the second relay unit is controlled so that the AC power supply side power supply line and the second diode unit are connected.
It is characterized by that.

In the present specification, direct current is also referred to as DC, and alternating current is also referred to as AC. Further, the "control unit" includes a processor such as an MPU (Micro Processing Unit), an IC (Integrated Circuit) including the processor, a control circuit for controlling each part of the power conversion device, and the like. Further, the "control power supply unit" refers to a configuration including a so-called power supply IC or the like, which receives power input of a predetermined voltage and supplies power to the control unit.

According to the power conversion device as described above, it has a circuit for transmitting DC power to the control power supply unit of the device and a circuit for transmitting AC power, and the converter of both circuits can be shared. Therefore, the device configuration can be simplified and the device cost can be reduced. Further, since the third circuit is not interrupted even when the inverter is in operation, even if some trouble occurs in the second circuit and DC power cannot be transmitted to the control power supply unit, the first circuit is used. It becomes possible to supply AC power from three circuits. That is, it can function as a backup circuit.

Further, the DC power supply may be a storage battery or a power generation device, the AC power supply connection unit may be an input / output terminal connected to a commercial power system, and the inverter unit may be a bidirectional inverter. Further, it may include a PCS (Power Conditioning System) for these. The power generation device referred to here includes a power generation device using natural energy such as solar power and wind power, a power generation device using fossil fuel, and a so-called fuel cell. With such a configuration, the present invention can be preferably carried out.

Further, the DC / DC converter may be an isolated converter that insulates the control power supply unit from the first circuit, the second circuit, and the third circuit. With such a configuration, the control power supply unit can be insulated from the main circuit, and safety can be improved.

Further, the DC power supply connection unit may be an input / output terminal connected to a storage battery, the AC power supply connection unit may be an input / output terminal connected to a commercial power system, and the inverter unit may be a bidirectional inverter. ..

Further, when the input DC voltage to the inverter unit exceeds a predetermined threshold value, the control unit may determine that the inverter unit is in an operating state and control the second relay unit. .. Since the inverter is provided with a means for measuring a normal voltage, it is possible to make a determination for switching the second relay unit without adding an additional configuration to the device. In addition, it is easy to set a threshold value for determination.

Further, when the control unit detects the switching operation start signal of the inverter unit, it may determine that the inverter unit is in the operating state and control the second relay unit. Even with such a configuration, it is possible to make a determination for switching the second relay unit without adding an additional configuration to the device. Since the actual switching operation is detected, it is possible to surely grasp that the inverter is operating.

Further, when the output AC voltage from the inverter unit exceeds a predetermined threshold value, the control unit may determine that the inverter unit is in an operating state and control the second relay unit. .. Further, the control unit may determine that the inverter unit is in an operating state and control the second relay unit when the output alternating current from the inverter unit exceeds a predetermined threshold value. .. When the AC voltage or current output from the inverter unit can be measured, it can be said that the AC power is output from the inverter unit, that is, the inverter is operating.

Further, when the voltage level of the contact of the third circuit with the inverter side power supply line and the contact with the AC power supply side power supply line in the first circuit is the same, the control unit is said to be the same. It may be determined that the inverter unit is in the operating state, and the second relay unit may be controlled.

Further, when the input DC current to the DC power supply connection unit exceeds a predetermined threshold value, the control unit determines that the inverter unit is in an operating state and controls the second relay unit. May be good.

Further, the control unit determines that the inverter unit is in an operating state when the output DC current from the DC power supply connection unit to the storage battery exceeds a predetermined threshold value, and controls the second relay unit. May be done.

Further, the storage battery includes a storage battery control system, and the control unit acquires information related to charging / discharging of the storage battery from the storage battery control system, and when the storage battery is in a predetermined charging / discharging state, the storage battery is in a predetermined charging / discharging state. It may be determined that the inverter unit is in an operating state, and the second relay unit may be controlled. Even if the operation of the inverter unit cannot be determined from the status in the power converter, if the information on charging / discharging is obtained from the storage battery, it means that the inverter unit is operating. It can be determined.

Further, the present invention can also be regarded as a grid interconnection system including the above-mentioned power conversion device.

In addition, each of the above configurations and processes can be combined with each other to construct the present invention as long as no technical contradiction occurs.

According to the present invention, in a power conversion device, the control unit that controls the device can be supplied with power from either a DC power supply or an AC power supply, and the device configuration can be simplified. Can be provided.

FIG. 1 is a block diagram showing a schematic configuration of a power conversion device 9 according to an application example of the present invention. FIG. 2 is a block diagram showing a schematic configuration of a grid-connected power storage system according to the first embodiment. FIG. 3 is a timing chart showing the timing of relay control performed by the power conversion device according to the first embodiment. FIG. 4 is a block diagram showing a schematic configuration of the system according to the first modification of the first embodiment. FIG. 5 is a block diagram showing a schematic configuration of a system according to a second modification of the first embodiment.

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

<Application example>
(Configuration of application example)
The present invention can be applied to, for example, the power conversion device 9 as shown in FIG. FIG. 1 is a block diagram showing a schematic configuration of a power conversion device 9 according to this application example. The power conversion device 9 according to this application example corresponds to a so-called power conditioner that converts DC power input from a storage battery, a photovoltaic power generation panel, another power generation system, or the like into AC power and outputs it.

As shown in FIG. 1, the power conversion device 9 includes a DC power supply connection unit 911, an AC power supply connection unit 912, an inverter 913, a first relay unit 914, a main circuit noise filter 915, a booster circuit 916, a first diode 921, and a first diode. It has two relay units 931, a second diode 932, a control power supply noise filter 933, a control unit 941, a control power supply unit 942, and an isolated power supply 943.

Further, in the power conversion device 9, the DC power supply connection unit 911 and the AC power supply connection unit 912 are connected, and the first circuit 91 in which the inverter 913 is arranged, and between the DC power supply connection unit 911 and the inverter 913. A second circuit 92 that branches and is connected to the control power supply unit 942, and a third circuit 93 that branches from between the AC power supply connection unit 912 and the inverter 913 and is connected to the control power supply unit 942 are formed. Will be done.

The DC power supply connection unit 911 includes an input / output terminal for inputting / outputting DC power to and from the outside, and a sensor (neither shown) for measuring the input / output DC voltage and current. Further, the AC power supply connection unit includes an input / output terminal for inputting / outputting AC power to / from the outside, and a sensor for measuring the input / output AC voltage and current.

The inverter 913 is provided with a switching circuit that converts DC power and AC power in both directions, and converts the input DC power into AC power or converts the input AC power into DC power and outputs the power. It is a bidirectional DC / AC inverter. When DC is input to the DC power supply connection unit 911 from the outside, the inverter 913 converts the DC power into AC power and outputs it to the AC power supply connection unit 912 side. On the other hand, when AC is input to the AC power supply connection unit 912 from the outside, the AC power is converted into DC power and output to the DC power supply connection unit 911 side. Further, the inverter 913 includes a sensor (not shown) for measuring input / output voltage and current on both the DC side and the AC side.

The first relay unit 914 is arranged between the AC power supply connection unit 912 and the inverter 913, and opens and closes a circuit between the two. Specifically, the control unit 941, which will be described later, relays on the AC power connection unit 912 and the inverter 913 when the inverter 913 is in operation, and relays on the AC power connection unit 912 and the inverter when the inverter 913 is stopped. Relay off with 913. That is, when the power conversion is not performed, the AC power connection unit 912 and the inverter 913 are electrically cut off.

The main circuit noise filter 915 is arranged on the AC output side of the inverter 913 to reduce noise generated in the AC power output from the inverter 913.

The booster circuit 916 is, for example, a DC / DC converter, and boosts the DC voltage output from the DC power supply connection unit 911 to a predetermined level.

The first diode 921 is arranged in the second circuit 92, and rectifies the DC power flowing through the second circuit 92 with the DC power supply connection portion 911 side as the anode and the control power supply portion 942 side as the cathode. The second diode 932 is arranged in the third circuit 93, and rectifies the AC power flowing through the third circuit 93 with the second relay 931 side as the anode and the control power supply unit 942 side as the cathode.

The second relay unit 931 is a so-called C-contact relay, which is arranged in the third circuit and has an inverter-side power supply line that branches from between the inverter 913 and the first relay unit 914, and the first relay unit 914. The AC power supply side power supply line branched from the AC power supply connection unit 912 is connected to the control power supply unit 942 so as to be switchable.

The control power supply noise filter 933 is arranged closer to the control power supply unit 942 than the second relay unit 931 in the third circuit 93 to reduce AC power noise.

The control unit 941 is configured to include, for example, a processor such as an MCU, an IC including the processor, a control circuit for controlling each part of the power conversion device, and the like, and controls each part of the power conversion device 9. The control power supply unit 942 is composed of a so-called power supply IC or the like, and receives the power supplied by the isolated power supply 943 described later, and transforms the power required for each configuration of the control unit 941 to perform its function as necessary. Supply while supplying.

The insulated power supply 943 is an isolated DC / DC converter such as a flyback system, and transforms the power input from the second circuit 92 and the third circuit 93 to a predetermined voltage (for example, 25V) to transform the first to first circuits. It is output to the control power supply unit 942 in an insulated state from the third circuit.

(Function of control unit)
In the power conversion device 9, the control unit 941 determines whether or not the inverter 913 is in an operating state by measuring the voltages of the DC power and the AC power input to the inverter 913. When power is supplied from either the DC power connection unit 911 or the AC power connection unit 912, the input voltage (and current) is measured by the sensor provided in the inverter 913, so that the inverter 913 operates. It can be determined that it is.

On the other hand, when power is not supplied from either the DC power supply connection unit 911 or the AC power supply connection unit 912, the inverter 913 is stopped. Specifically, when the input voltage measured by the sensor of the inverter 913 falls below a predetermined value, it can be determined that the inverter 913 has stopped (or will soon stop) its operation.

Then, when the inverter 913 is in the operating state, the control unit 941 relays on the first relay unit 914 and controls the second relay unit 931 so as to be connected to the power supply line on the inverter side. On the other hand, when the inverter 913 is in the stopped state, the first relay unit 914 is relayed off, and the second relay unit 931 is controlled to be connected to the AC power supply side power supply line.

Therefore, while the inverter 913 is in operation, power is supplied to the control power supply unit 942 from the second circuit 92 and the third circuit 93 connected by the inverter side power supply line. On the other hand, when the inverter 913 is in the stopped state, power is supplied to the control power supply unit 942 only from the third circuit 93 connected by the AC power supply side power supply line.

Actually, when the inverter 913 is in the stopped state, the power is not supplied from either the DC power supply connection unit 911 or the AC power supply connection unit 912, and the power for operating the control unit 941 is not supplied. It will be. Therefore, when the input voltage to the inverter 913 falls below a predetermined value, the control unit 941 sets the second relay unit 931 on the AC power supply side before the power supply to the control power supply unit 942 is completely cut off. It may be switched to connect to the power supply line.

When the above power conversion device 9 is used in a power conversion system in which the AC power supply is a commercial power system and the DC power supply is a storage battery, for example, the power supply from the AC power supply is interrupted for some reason, and the storage battery further becomes Even if the power converter 9 is stopped due to over-discharging, the system can be restored when the power supply from the AC power source is restored.

Further, by sharing the insulated power supply 943 between the DC side circuit (second circuit) and the AC side circuit (third circuit) for supplying power to the control power supply unit 942, the device can be downsized and manufactured. The cost can be reduced.

Further, even when the first relay unit 914 is relayed on, the control power supply unit 942 is always supplied with power from the third circuit 93 because the third circuit 93 is connected by the inverter side power supply line. Will be. Therefore, even if some trouble occurs in the second circuit 92 and the power cannot be supplied to the control power supply unit 942 via the second circuit 92, the power can be supplied from the third circuit 93.

<Embodiment 1>
Next, the grid interconnection power storage system 1 which is an example of the embodiment of the present invention will be described. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention to those.

(System configuration)
The overall configuration of the grid-connected power storage system 1 according to the embodiment of the present invention will be described with reference to FIG. The grid-connected power storage system 1 has a power conversion device 10 and a storage battery unit 20, and the power conversion device 10 is connected to the storage battery unit 20 by the DC power supply connection unit 111 and the system 30 by the AC power supply connection unit 112. ing.

The power conversion device 10 includes a DC power supply connection unit 111, an AC power supply connection unit 112, an inverter 113, a first relay unit (interconnection relay unit) 114, a booster circuit 115, a first diode 121, and a second relay unit (switching relay unit). ) 131, a second diode 132, a control unit 141, a control power supply unit 142, an isolated power supply 143, and a main circuit noise filter and a control power supply noise filter (not shown).

Since the power conversion device 10 has the same configuration as the power conversion device 9 described in the application example and each component is also the same as that described in the application example, detailed description of each component is omitted. To do. Further, the first circuit that connects the DC power supply connection unit 111 and the AC power supply connection unit 112, and the second circuit that branches from between the DC power supply connection unit 111 and the inverter 113 and is connected to the control power supply unit 142. The same applies to the fact that a third circuit, which is branched from between the AC power supply connection unit 112 and the inverter 113 and is connected to the control power supply unit 142, is formed. The same applies to the fact that the third circuit includes an inverter-side power supply line and an AC power supply-side power supply line.

The storage battery unit 20 includes a storage battery 21, a DC input / output unit 22, a DC relay unit 23, a circuit breaker 24, a control power supply unit 25, and a BMS (Battery Management Unit) 26.

The storage battery 21 is, for example, a storage battery such as a lithium ion battery, and charges and discharges electric power according to the control of the BMS 26. The DC input / output unit 22 includes a DC input / output terminal connected to the power conversion device 10 and a sensor for measuring voltage and current. The DC relay unit 23 switches the connection and disconnection of the current with the DC input / output unit 22 according to the control of the BMS 26. The BMS 26 functions as a control unit that controls each component of the storage battery unit 20.

(System operation)
The grid-connected power storage system 1 receives power from the system 30 (purchases) during a time when the power charge is low, such as at night, and converts the power from alternating current to direct current with the power conversion device 10. , Output to the storage battery unit 20 to charge the storage battery 21 with electric power. When the storage battery 21 has power equal to or higher than a predetermined value (for example, about 10% SOC), it is discharged from the storage battery 21 and power is supplied to the power conversion device 10 (and the load connected to the power conversion device 10). ..

On the other hand, when the SOC (States Of Charge) of the storage battery 21 becomes 10% or less, the BMS 26 controls to relay off the DC relay unit 23 and stops the supply of electric power from the storage battery 21 to the power conversion device 10. The power supply from the storage battery 21 to the control power supply unit 25 is continuously performed, and if the power supply to the control power supply unit 25 is exhausted, the circuit breaker 24 is operated to connect the storage battery 21 and the circuit. To protect the circuit. In this case, manual recovery by the user is required.

When the supply of electric power from the storage battery 21 to the electric power converter 10 is stopped, if the electric power can be supplied from the system 30, the electric power converter 10 receives the electric power from the system 30 and maintains the operating state. be able to. Then, electric power can be converted as needed to supply electric power to the storage battery 21. In this case, the BMS 26 controls to relay on the DC relay unit 23 to connect the circuit.

On the other hand, when the power supply to the power conversion device 10 is stopped due to a power failure or the like in the system 30, the inverter 113 is stopped and the power supply to the control unit 141 of the power conversion device 10 is cut off. ..

At this time, the control unit 141 relays off the first relay unit 114 as described in the application example, and the first relay and the second relay so that the third circuit is connected by the AC power supply side power supply line. To control. Then, when the power supply from the system 30 is restored, the power is supplied to the control power supply unit 142 and the control unit 141 via the third circuit connected by the AC power supply side power supply line.

The control unit 141 that has received the power supply communicates with the BMS 26 by a communication method such as CAN (Controller Area Network), and transmits the recovery of the power supply. Then, the BMS 26 outputs the recovery power remaining in the storage battery 21 to the power conversion device 10 to operate the inverter 113.

Then, when the control unit 141 detects that the inverter 113 is in the operating state, the control unit 141 switches the second relay unit 131 so as to be connected by the inverter side power supply line, and relays on the first relay unit. Perform grid interconnection operation. FIG. 3 shows the relationship between the operating / stopped state of the inverter 113 and the connection state of each relay unit in this series.

At the monitoring point in FIG. 3, various methods for detecting the operation of the inverter 113 can be considered. For example, when the input DC voltage to the inverter 113 exceeds a predetermined threshold value, it may be determined that the inverter 113 is in operation.

Further, when the switching operation start signal of the inverter 113 is detected, it may be determined that the operation of the inverter 113 is ON. Further, when the output AC voltage from the inverter 113 exceeds a predetermined threshold value, it may be determined that the inverter 113 is in operation. Further, when the output alternating current from the inverter 113 exceeds a predetermined threshold value, it may be determined that the operation of the inverter 113 is ON. Further, when the voltage levels at both ends of the second relay unit 131 are the same, it may be determined that the inverter 113 is in operation.

Further, when the input DC current to the DC power supply connection unit 111 exceeds a predetermined threshold value, it may be determined that the inverter 113 is in operation. Further, when the output DC current from the DC power supply connection unit 111 to the DC input / output unit 22 exceeds a predetermined threshold value, it may be determined that the inverter 113 is in operation. Further, when the information that the storage battery 21 is in a predetermined charge / discharge state is acquired from the BMS 26, it may be determined that the inverter 113 is in operation ON.

It should be noted that the detection that the operation of the inverter 113 is OFF, that is, the stopped state can also be performed by various methods in the same manner as described above.

According to the grid-connected power storage system 1 as described above, it is possible to provide a power storage system capable of automatically recovering from a power failure from the system 30 for a long time while simplifying the configuration of the power converter 10. Become.

<Others>
The above-described embodiment is merely an example of the present invention, and the present invention is not limited to the above-mentioned specific embodiment. The present invention can be modified in various ways within the scope of its technical idea. For example, it may be a system for connecting power generation equipment instead of the configuration of the storage battery of the first embodiment, or a system for connecting another power generation system or a load in addition to the embodiment of the first embodiment.

FIG. 4 is a schematic diagram showing a system configuration of a first modification of the grid-connected power storage system 1 according to the first embodiment. In the grid-connected power storage system 2, as compared with the grid-connected power storage system 1 of the first embodiment, the self-sustaining load 40, the photovoltaic power generation panel 50, and the photovoltaic power generation power conditioning system 51 are connected to the power conversion device 100. It differs in that it is the same as the configuration of the first embodiment in other points. The same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The power conversion device 100 of the grid-connected power storage system 2 branches from between the inverter 113 and the first relay unit 114, and has an independent output terminal 151 that supplies AC power to an external independent load, and a photovoltaic power conditioning system. It is provided with an independent input terminal 152 that receives AC power from 51. With such a system configuration, the photovoltaic power generation system and the power storage system can be combined and implemented. The power generation system is not limited to sunlight, and can be combined with other power generation equipment such as a wind power generation system.

The grid-connected power storage system 1 and the grid-connected power storage system 2 are examples of the grid-connected power storage system according to the present invention, and the power conversion device according to the present invention does not necessarily have to be used in combination with a storage battery. An example of such a grid interconnection system will be described with reference to FIG.

FIG. 5 is a diagram showing a schematic configuration of a grid interconnection system 3 according to another modification of the first embodiment. As shown in FIG. 5, in the grid interconnection system 3, the photovoltaic power generation panel 50 is connected to the power conversion device 100 instead of the storage battery unit 20 as compared with the grid interconnection power storage system 1 of the first embodiment. It differs in that it is the same as the configuration of the first embodiment in other points. The same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

Further, in each of the above examples, the DC / DC converter connected to the control power supply unit is an isolated type converter, but the converter does not necessarily have to be an isolated type.

<Additional notes>
One aspect of the present invention is
The DC power supply connection (911) connected to the DC power supply and
The AC power connection (912) connected to the AC power and
Inverter section (913) and
Control unit (941) and
A control power supply unit (942) that supplies electric power to the control unit, and
A first circuit (91) that connects the DC power supply connection unit and the AC power supply connection unit and arranges the inverter unit, and
In the first circuit, it is arranged between the inverter unit and the AC power supply connection unit, and when the inverter unit is in a stopped state, the connection between the inverter unit and the AC power supply connection unit is opened. 1 relay part (914) and
A second circuit (92) that branches from between the DC power supply connection unit and the inverter unit and transmits DC power to the control power supply unit.
A first diode section (921) arranged in the second circuit and having the control power supply section on the downstream side, and
A third circuit (93) that branches from between the AC power connection unit and the inverter unit and transmits AC power to the control power supply unit.
An inverter-side power supply line that is arranged in the third circuit and branches from between the inverter and the first relay, and an AC power supply that branches from between the first relay and the AC power connection. The second relay unit (931), which connects the power supply line to the control power supply unit side so as to be switchable,
In the third circuit, a second diode unit (932) arranged between the second relay unit and the control power supply unit and having the control power supply unit on the downstream side and a second diode unit (932).
A DC / DC converter (943) that transforms the electric power shared in the second circuit and the third circuit and transmitted to the second circuit and the third circuit to a predetermined voltage and supplies the power to the control power supply unit. And have
The control unit
When the inverter unit is in an operating state, the second relay unit is controlled so that the power supply line on the inverter side and the second diode unit are connected to each other.
When the inverter unit is in the stopped state, the second relay unit is controlled so that the AC power supply side power supply line and the second diode unit are connected.
The power conversion device (9) is characterized in that.

1, 2 ... Grid interconnection power storage system 3 ... Grid interconnection system 9, 10, 100 ... Power converter 91 ... 1st circuit 92 ... 2nd circuit 93 ... 3rd Circuits 111, 911 ... DC power supply connection 112, 912 ... AC power supply connection 113, 913 ... Inverter 114, 914 ... First relay 115, 916 ... Boost circuit 121, 921 ...・ ・ 1st diode 131, 931 ・ ・ ・ 2nd relay part 132, 932 ・ ・ ・ 2nd diode 141, 941 ・ ・ ・ Control part 142, 942 ・ ・ ・ Control power supply part 143, 943 ・ ・ ・ Insulated power supply 20・ ・ ・ Storage battery unit 21 ・ ・ ・ Storage battery 22 ・ ・ ・ DC input / output unit 23 ・ ・ ・ DC relay unit 24 ・ ・ ・ Circuit breaker 25 ・ ・ ・ Control power supply unit 26 ・ ・ ・ BMS
30 ・ ・ ・ Commercial power system 50 ・ ・ ・ Photovoltaic panel 51 ・ ・ ・ Photovoltaic power conditioning system

Claims (13)

DC power supply connection connected to DC power supply and
The AC power connection connected to the AC power and the AC power connection
Inverter part and
Control unit and
A control power supply unit that supplies power to the control unit,
A first circuit that connects the DC power supply connection unit and the AC power supply connection unit and arranges the inverter unit, and
In the first circuit, it is arranged between the inverter unit and the AC power supply connection unit, and when the inverter unit is in a stopped state, the connection between the inverter unit and the AC power supply connection unit is opened. 1 relay part and
A second circuit that branches from between the DC power supply connection unit and the inverter unit and transmits DC power to the control power supply unit.
A first diode section arranged in the second circuit and having the control power supply section on the downstream side,
A third circuit that branches from between the AC power connection unit and the inverter unit and transmits AC power to the control power supply unit.
An inverter-side power supply line that is arranged in the third circuit and branches from between the inverter and the first relay, and an AC power supply that branches from between the first relay and the AC power connection. The second relay unit, which connects the power supply line to the control power supply unit side in a switchable manner,
In the third circuit, a second diode section arranged between the second relay section and the control power supply section and having the control power supply section on the downstream side and a second diode section.
A DC / DC converter that is shared by the second circuit and the third circuit and that transforms the electric power transmitted to the second circuit and the third circuit to a predetermined voltage and supplies the power to the control power supply unit. Have and
The control unit
When the inverter unit is in an operating state, the second relay unit is controlled so that the power supply line on the inverter side and the second diode unit are connected to each other.
When the inverter unit is in the stopped state, the second relay unit is controlled so that the AC power supply side power supply line and the second diode unit are connected.
A power conversion device characterized by the fact that. The DC power supply is a storage battery, the AC power supply connection unit is an input / output terminal connected to a commercial power system, and the inverter unit is a bidirectional inverter.
The power conversion device according to claim 1, wherein the power conversion device is characterized by the above. The DC power supply is a power generation device, the AC power supply connection unit is an input / output terminal connected to a commercial power system, and the inverter unit is a bidirectional inverter.
The power conversion device according to claim 1, wherein the power conversion device is characterized by the above. The DC / DC converter is an isolated converter that insulates the control power supply unit from the first circuit, the second circuit, and the third circuit.
The power conversion device according to any one of claims 1 to 3, wherein the power conversion device is characterized by the above. The control unit
When the input DC voltage to the inverter unit exceeds a predetermined threshold value, it is determined that the inverter unit is in an operating state, and the second relay unit is controlled.
The power conversion device according to any one of claims 1 to 4, wherein the power conversion device is characterized by the above. The control unit
When the switching operation start signal of the inverter unit is detected, it is determined that the inverter unit is in the operating state, and the second relay unit is controlled.
The power conversion device according to any one of claims 1 to 4, wherein the power conversion device is characterized by the above. The control unit
When the output AC voltage from the inverter unit exceeds a predetermined threshold value, it is determined that the inverter unit is in an operating state, and the second relay unit is controlled.
The power conversion device according to any one of claims 1 to 4, wherein the power conversion device is characterized by the above. The control unit
When the output AC current from the inverter unit exceeds a predetermined threshold value, it is determined that the inverter unit is in an operating state, and the second relay unit is controlled.
The power conversion device according to any one of claims 1 to 4, wherein the power conversion device is characterized by the above. The control unit
The inverter unit is in an operating state when the voltage levels of the contacts of the third circuit with the inverter side power supply line and the contacts of the AC power supply side power supply line in the first circuit are the same. To control the second relay unit.
The power conversion device according to any one of claims 1 to 4, wherein the power conversion device is characterized by the above. The control unit
When the input DC current to the DC power supply connection unit exceeds a predetermined threshold value, it is determined that the inverter unit is in an operating state, and the second relay unit is controlled.
The power conversion device according to any one of claims 1 to 4, wherein the power conversion device is characterized by the above. The control unit
When the output DC current from the DC power supply connection unit to the storage battery exceeds a predetermined threshold value, it is determined that the inverter unit is in an operating state, and the second relay unit is controlled.
The power conversion device according to claim 2, wherein the power conversion device is characterized by the above. The storage battery is provided with a storage battery control system.
The control unit
Information on the charge / discharge of the storage battery is acquired from the storage battery control system, and when the storage battery is in a predetermined charge / discharge state, it is determined that the inverter unit is in the operating state, and the second relay unit Take control,
The power conversion device according to claim 2, wherein the power conversion device is characterized by the above. A grid interconnection system comprising the power conversion device according to any one of claims 1 to 12.

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