JP7316645B2 - Shutdown system, shutdown method and program - Google Patents

Description

The present invention relates to a shutdown system, shutdown method and program.

A rapid shutdown standard exists as a standard for reducing the risk of electric shock or the like during firefighting activities by firefighters when a fire breaks out in a building or the like in which solar panels are installed. In the Rapid Shutdown Standard, the DC voltage within 30 cm from the solar panel installed in the building should be stepped down to 80 V or less within 10 seconds, and the DC voltage outside the area should be stepped down to 30 V or less within 10 seconds. is obligatory.

Patent Literature 1 discloses a technique related to a safety switch. Specifically, a safety switch is provided for each solar panel, and in the event of an emergency, each safety switch is operated to cut off the connection between the solar panels, thereby stepping down the DC voltage. As a result, the DC voltage inside and outside the above range can be stepped down to within the specified value, and the rapid shutdown standard can be complied with.

JP 2018-038254 A

However, the technology disclosed in Patent Literature 1 above requires a safety switch for each solar panel, which is costly.

Accordingly, the present invention provides a shutdown system or the like that can conform to the rapid shutdown standard at low cost.

In order to achieve the above object, one aspect of the shutdown system according to the present invention includes a power conversion device that converts DC power generated by a solar panel into AC power, and the power conversion device receives a signal indicating an emergency. is acquired, and if it is determined that the signal is acquired, the positive side transmission line connecting the positive side of the solar panel and the power conversion device, and the negative side of the solar panel Control is performed so that the DC voltage between the negative side transmission line connecting to the power conversion device is 30 V or less.

Further, in order to achieve the above object, one aspect of the shutdown method according to the present invention determines whether or not a signal indicating an emergency has been acquired, and if it is determined that the signal has been acquired, the solar panel is in the correct state. a positive side transmission line that connects a side and a power conversion device that converts DC power generated by the solar panel into AC power; and a negative side transmission that connects the negative side of the solar panel and the power conversion device. Control is performed so that the DC voltage between

In order to achieve the above object, one aspect of a program according to the present invention is a program for causing a computer to execute the above shutdown method.

According to one aspect of the present invention, it is possible to comply with the rapid shutdown standard at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows an example of the photovoltaic power generation system to which the shutdown system which concerns on embodiment was applied. 4 is a flow chart showing an example of the operation of the shutdown system according to the embodiment; FIG. 10 is a configuration diagram showing an example of a photovoltaic power generation system to which a shutdown system according to a modification of the embodiment is applied;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. All of the embodiments described below represent specific examples of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, etc. shown in the following embodiments are examples and are not intended to limit the present invention.

Each figure is a schematic diagram and is not necessarily strictly illustrated. Moreover, in each figure, the same code|symbol is attached|subjected to the substantially same structure, and the overlapping description is abbreviate|omitted or simplified.

(Embodiment)
A shutdown system according to an embodiment will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing an example of a photovoltaic power generation system to which a shutdown system 1 according to an embodiment is applied. In addition to the configuration of the shutdown system 1, FIG. 1 also shows a solar panel 50 in the solar power generation system.

A photovoltaic power generation system is a system in which DC power supplied from a plurality of solar panels 50 installed on the roof of a building or the like is converted into AC power by a power converter 10 such as a power conditioner. As shown in FIG. 1, the positive side of the solar panel 50 and the power conversion device 10 are connected by a positive side transmission line 51, and the negative side of the solar panel 50 and the power conversion device 10 are connected by a negative side transmission line 52. connected with A string is formed by the positive transmission line 51, the negative transmission line 52, and the plurality of solar panels 50 connected in series.

The solar panel 50 generates DC power by receiving sunlight or the like on its light receiving surface. One solar panel 50 generates a DC voltage of, for example, 50V to 60V, depending on the intensity of received light. In the event of an emergency such as a fire in a building where solar panels are installed, the DC voltage in the area within 30 cm from the solar panel is stepped down to 80V or less within 10 seconds, and the DC voltage outside the area is reduced to 10V. There is a rapid shutdown standard that mandates stepping down to 30V or less within seconds. The shutdown system 1 is applied to a photovoltaic system so that the photovoltaic system can comply with the rapid shutdown standard.

The shutdown system 1 is a system that includes a power conversion device 10 that converts DC power generated by a solar panel 50 into AC power. In this aspect, the shutdown system 1 includes a power conversion device 10 and an operation switch 30 .

The power electronics device 10 is, for example, a power conditioner. The power conversion device 10 converts DC power supplied from the solar panel 50 via the positive transmission line 51 into AC power. The power conversion device 10 employs, for example, an MPPT (Maximum Power Point Tracking) method, and normally adjusts the current and voltage of the DC power supplied from the solar panel 50 to values that maximize the power. . For example, the power converter 10 normally converts DC power into AC power with a voltage of 100 V and a frequency of 50 Hz or 60 Hz.

On the other hand, in an emergency, the power converter 10 does not adjust the power to the maximum value, but adjusts the current to the maximum. In the MPPT method of a normal power conditioner, such an adjustment is not performed, but since the MPPT method is a method that can adjust the current, the adjustment that ignores maximizing the power and increases the current anyway is also possible. When the current of the DC power supplied from the solar panel 50 is adjusted, the voltage of the DC power supplied from the solar panel 50, that is, the DC voltage between the positive transmission line 51 and the negative transmission line 52 is also adjusted. In this aspect, the power conversion device 10 reduces the DC voltage by performing control to increase the current in an emergency.

Although details will be described later with reference to FIG. 2, the power conversion device 10 determines whether or not a signal indicating an emergency has been acquired, and if it determines that the signal has been acquired, the positive side of the solar panel 50 and the power The DC voltage between the positive side transmission line 51 connecting the conversion device 10 and the negative side transmission line 52 connecting the negative side of the solar panel 50 and the power conversion device 10 is controlled to be 30 V or less. For example, the power electronics device 10 is a computer including a processor (for example, a microcomputer), memory, etc. The above control is realized by the processor executing a program stored in the memory.

The operation switch 30 is, for example, a switch that is operated by a person, and is provided indoors or outdoors (a wall of a building, etc.) such as a building in which a plurality of solar panels 50 are installed. The operation switch 30 is operated when a fire breaks out in a building or the like in which a plurality of solar panels 50 are installed, or a disaster (earthquake, flood, etc.) occurs. When the operation switch 30 is operated, it outputs a signal indicating that the operation switch 30 has been operated. The operation switch 30 and the power converter 10 are connected by wire or wirelessly, and the operation switch 30 outputs the above signal to the power converter 10 by being operated. The operation switch 30 is, for example, a push button.

Next, details of the operation of the shutdown system 1 will be described with reference to FIG.

FIG. 2 is a flow chart showing an example of the operation of the shutdown system 1 according to the embodiment.

The power electronics device 10 determines whether or not a signal indicating an emergency has been acquired (step S11). A signal indicating an emergency is, for example, a signal indicating that the operation switch 30 has been operated. That is, the power conversion device 10 can determine whether or not to perform an emergency operation by determining whether or not the operation switch 30 has been operated.

When the power conversion device 10 determines that the signal is not acquired (No in step S11), the power conversion device 10 performs normal operation while preparing for emergencies.

When the power electronics device 10 determines that the signal has been acquired (Yes in step S11), the power conversion device 10 controls the DC voltage between the positive transmission line 51 and the negative transmission line 52 to be 30 V or less (step S12). ). Specifically, the power converter 10 performs the control by adjusting the current of the DC power supplied from the solar panel 50 as described above. By this control, the DC voltage between the positive transmission line 51 and the negative transmission line 52 becomes 30 V or less within 10 seconds (for example, within several seconds). The voltage drops to 80V or less within 10 seconds, and the DC voltage outside the region drops to 30V or less within 10 seconds. In a normal power conditioner, control is not performed so that the DC voltage is 30 V or less. Control is performed so that the voltage becomes 30 V or less.

As described above, the shutdown system 1 according to the present embodiment includes the power conversion device 10 that converts the DC power generated by the solar panel 50 into AC power. The power conversion device 10 determines whether or not a signal indicating an emergency has been acquired, and if it is determined that the signal has been acquired, the positive side transmission path connecting the positive side of the solar panel 50 and the power conversion device 10 51 and the negative side transmission line 52 connecting the negative side of the solar panel 50 and the power converter 10 is controlled to be 30 V or less.

According to this, in an emergency, the DC voltage between the positive side transmission line 51 and the negative side transmission line 52 can be reduced to 30 V or less by the power conversion device 10 such as a power conditioner, and it conforms to the rapid shutdown standard. can. In particular, in this aspect, for example, it is not necessary to provide a safety switch or the like for each solar panel 50, and it is only necessary to change the control method of the power converter 10, so the rapid shutdown standard can be complied with at low cost.

The shutdown system 1 may further include an operation switch 30, and the signal indicating the emergency may be a signal indicating that the operation switch 30 has been operated. For example, the operation switch 30 may be a push button.

According to this, by operating the operation switch 30, the DC voltage can be easily reduced to 30 V or less. For example, when the operation switch 30 is a push button, the operation of the operation switch 30 can be a simple operation of pushing.

(Modification)
The shutdown system 1 includes the power conversion device 10 as a configuration for reducing the DC voltage between the positive transmission line 51 and the negative transmission line 52 to 30 V or less. may be further provided in addition to the power conversion device 10 . This will be described with reference to FIG. 3 as a modification of the embodiment.

FIG. 3 is a configuration diagram showing an example of a photovoltaic power generation system to which a shutdown system 2 according to a modification of the embodiment is applied.

The shutdown system 2 differs from the shutdown system 1 in that it further includes a short-circuit switch 20 . Since other points are the same as those in the shutdown system 1, description thereof is omitted.

The short-circuit switch 20 is a switch for short-circuiting the positive transmission line 51 and the negative transmission line 52 . The short-circuit switch 20 is, for example, a semiconductor switch or a relay, and is switched between a conducting state and a non-conducting state by an external signal. For example, the short-circuit switch 20 is switched between a conducting state and a non-conducting state according to a signal indicating that the operation switch 30 has been operated. For example, the short-circuit switch 20 becomes conductive by acquiring a signal indicating that the operation switch 30 has been operated, that is, short-circuits the positive transmission line 51 and the negative transmission line 52 . On the other hand, the short-circuit switch 20 is in a non-conducting state, that is, opens the positive transmission line 51 and the negative transmission line 52 when it does not acquire a signal indicating that the operation switch 30 has been operated. For example, the shorting switch 20 may be a thyristor.

As described above, the shutdown system 2 may further include the short-circuit switch 20 for short-circuiting the positive transmission line 51 and the negative transmission line 52 .

According to this, by short-circuiting the positive side transmission line 51 and the negative side transmission line 52 with the short-circuit switch 20, the DC voltage can be reduced to 30 V or less (approximately 0 V). In the event of an emergency, the power conversion device 10 may be destroyed and the power conversion device 10 may not be able to reduce the DC voltage to 30 V or less. By providing the switch 20, the DC voltage can be more reliably set to 30 V or less.

Alternatively, the short-circuit switch 20 may be a semiconductor switch or a relay.

Thus, the short-circuit switch 20 may be realized with a semiconductor switch or a relay.

Alternatively, the short-circuit switch 20 may be a thyristor.

For example, a normal switch becomes conductive while a signal for making it conductive is input, and becomes non-conductive when the input of the signal is stopped. For example, in a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), while a voltage is applied to the gate to make the MOSFET conductive, the source-drain becomes conductive. becomes non-conducting. When such a normal switch is used as the short-circuit switch 20, in an emergency, the short-circuit switch 20 enters a conductive state when a signal is input from a device that controls the short-circuit switch 20 (here, the operation switch 30). After that, if the device is destroyed or the communication line connecting the device and the short-circuit switch 20 is broken, the signal will not be input and the short-circuit switch 20 will be in a non-conducting state. On the other hand, once the thyristor is in a conductive state, the conductive state is maintained while the current is passing through the thyristor unless a signal for canceling the conductive state is input from the outside. For example, while the solar panel 50 is receiving sunlight, if the thyristor is in a conducting state, the current from the solar panel 50 passes through the thyristor. The thyristor can be maintained in a conducting state at all times. Therefore, in an emergency, even if the device controlling the short-circuit switch 20 is destroyed after the short-circuit switch 20 (thyristor) becomes conductive, the short-circuit switch 20 can be maintained in the conductive state. The DC voltage between the positive transmission line 51 and the negative transmission line 52 can be maintained at 30V or less.

(Other embodiments)
Although the shutdown systems 1 and 2 according to the embodiments have been described above, the present invention is not limited to the above embodiments.

For example, in the above-described embodiment, the signal indicating an emergency is a signal indicating that the operation switch 30 has been operated, but the present invention is not limited to this. For example, the signal indicating an emergency may be a signal indicating that an abnormality detection sensor such as a fire sensor or smoke sensor has detected an abnormality.

Further, for example, in the above-described embodiment, the operation switch 30 is a push button, but it is not limited to this.

In addition, the present invention can be implemented not only as the shutdown systems 1 and 2, but also as a shutdown method including steps (processes) performed by each constituent element of the shutdown systems 1 and 2. FIG.

Specifically, as shown in FIG. 2, in the shutdown method, it is determined whether or not a signal indicating an emergency has been acquired (step S11), and if it is determined that the signal has been acquired (Yes in step S11). , a positive side transmission line 51 that connects the positive side of the solar panel 50 and the power conversion device 10 that converts the DC power generated by the solar panel 50 to AC power, and the negative side of the solar panel 50 and power conversion. Control is performed so that the DC voltage between the device 10 and the negative transmission line 52 is 30 V or less (step S12).

For example, those steps may be performed by a computer (computer system). The present invention can be realized as a program for causing a computer to execute the steps included in those methods. Furthermore, the present invention can be implemented as a non-temporary computer-readable recording medium such as a CD-ROM recording the program.

Although the shutdown systems 1 and 2 according to the above-described embodiments are implemented in software by a microcomputer, they may be implemented in software in a general-purpose computer such as a personal computer. Furthermore, the shutdown systems 1 and 2 may be implemented in hardware by dedicated electronic circuits composed of A/D converters, logic circuits, gate arrays, D/A converters, and the like.

In addition, it can be realized by applying various modifications to each embodiment that a person skilled in the art can think of, or by arbitrarily combining the constituent elements and functions of each embodiment without departing from the spirit of the present invention. Forms are also included in the present invention.

Reference Signs List 1, 2 shutdown system 10 power converter 20 short-circuit switch 30 operation switch 50 solar panel 51 positive transmission line 52 negative transmission line

Claims (8)

Equipped with a power conversion device compatible with the MPPT method that converts DC power generated by a solar panel into AC power,
The power converter,
Determining whether or not a signal indicating an emergency has been acquired,
When it is determined that the signal has been acquired , the solar panel does not adjust the DC power supplied from the solar panel to the maximum value, but adjusts the current to the maximum value . Control to make the DC voltage between the positive side transmission line connecting the positive side of and the power converter and the negative side transmission line connecting the negative side of the solar panel and the power converter to 30 V or less Do a shutdown system. The shutdown system further comprises an operation switch,
The shutdown system according to claim 1, wherein the emergency signal is a signal indicating that the operation switch has been operated. 3. The shutdown system according to claim 2, wherein said operating switch is a push button. The shutdown system according to any one of claims 1 to 3, further comprising a short-circuit switch for short-circuiting the positive transmission line and the negative transmission line. 5. The shutdown system of Claim 4, wherein the shorting switch is a semiconductor switch or a relay. 5. The shutdown system of Claim 4, wherein the shunt switch is a thyristor. Determining whether or not a signal indicating an emergency has been acquired,
When it is determined that the signal has been acquired , the direct current power supplied from the solar panel is not adjusted to the maximum value, but the current is adjusted to the maximum value, so that the solar panel is positive. A positive side transmission line that connects the side and a power conversion device compatible with the MPPT system that converts DC power generated by the solar panel to AC power, and a negative side of the solar panel and the power conversion device. A shutdown method for controlling the DC voltage between the negative side transmission line to be 30 V or less. A program for causing a computer to execute the shutdown method according to claim 7.

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