JP6917543B2 - Controls, power conversion systems, and power generation systems - Google Patents

Description

The present invention relates to a control device, a power conversion system, and a power generation system.

With increasing awareness of environmental issues and the introduction of a power sales system, power generation devices that use natural energy such as solar cells have become widespread. The power generation device is used in a residential-installed power generation system or a so-called mega solar power plant (power generation system). These power generation systems include the above-mentioned power generation device and a power conversion device (sometimes referred to as a "power conditioner") that converts DC power transmitted from the power generation device into AC power. It is mainstream. Here, the power conversion device includes electric elements such as an inverter circuit and a booster circuit. The AC power converted by the power conversion device is supplied to the power system and the load in the building (in the case of a residential power generation system).

While the spread of power generation systems that use natural energy contributes to reducing the environmental load, it causes excessive power supply to the power system during daytime hours when the amount of power generation is high, and the voltage of the power system becomes high. There is a possibility that it will rise above the specified value.

In order to avoid such a situation, each electric power company sends schedule information for suppressing the output power to the power generation system. In order to receive the schedule information, the power generation system includes a control device including a control signal transmission function for controlling the power conversion device to suppress the output power, in addition to the function of receiving the schedule information from the electric power company. As a power generation system having such a configuration, for example, the technique described in Patent Document 1 is disclosed.

Japanese Unexamined Patent Publication No. 2016-178719

Here, the control device transmits the control signal to the power conversion device based on the received schedule information. On the other hand, when using a solar cell as a power generation device, sunset (
During the hours when there is no (or very little) sunlight from sunset) to the next sunrise,
As a matter of course, the state without power generation will continue. In the conventional power generation system, the control device continues to transmit the control signal to the power conversion device even during the time when such power generation is not performed.

In this case, the control device is operating unnecessarily in a time zone in which the operation should not be necessary. That is, the control device consumes electric power that does not have to be used originally. In view of the above problems, an object of the present invention is to provide a control device capable of saving power. Another object of the present invention is to provide a power conversion system and a power generation system including the control device.

The control device according to the present invention includes a power conversion device that converts the generated power of a solar cell into AC power and outputs the AC power to a power system, a server that transmits schedule information for suppressing the output power of the power conversion device, and a server. A first signal for controlling the output of the power conversion device, which is communicably connected, receives schedule information for suppressing the output power of the power conversion device from the server, and is generated based on the schedule information. It is characterized in that it is periodically transmitted to the power conversion device, and when the generated power of the solar cell is equal to or less than a predetermined value, the transmission of the first signal is stopped.

Further, the power conversion system according to the present invention includes a power conversion device that converts the generated power of the solar cell into AC power and outputs the AC power to the power system, and a schedule for suppressing the output of the power conversion device from the server. The control device includes a control device that receives information and periodically transmits a first signal for controlling the output of the power conversion device generated based on the schedule information to the power conversion device. When the generated power of the solar cell is equal to or less than a predetermined value, the transmission of the first signal is stopped.

Further, the power generation system according to the present invention suppresses the output of the solar cell, the power conversion device that converts the generated power of the solar cell into AC power and outputs the AC power to the power system, and the output of the power conversion device from the server. The control device includes a control device that receives the schedule information for the operation and periodically transmits a first signal for controlling the output of the power conversion device, which is generated based on the schedule information, to the power conversion device. The apparatus is characterized in that the transmission of the first signal is stopped when the generated power of the solar cell is equal to or less than a predetermined value.

The control device according to the present invention can save power in the control device. In addition, a power conversion system and a power generation system including the control device can be provided.

The system schematic diagram of the power generation system 10 which concerns on embodiment of this invention. The wiring system schematic diagram of the power conversion apparatus 2 which concerns on embodiment of this invention. The figure which shows an example of the schedule information 7 transmitted from the power management server 3. The hardware block diagram of the control device 5 which concerns on embodiment of this invention. The sequence diagram which shows the operation of the control device 5 and the power conversion device 2 which concerns on embodiment of this invention.

Hereinafter, the power generation system according to the embodiment of the present invention will be described with reference to the drawings. First, the outline of the configuration of the power generation system 10 according to the present embodiment will be described with reference to FIG. Figure 1
Is a system conceptual diagram for explaining the power generation system 10.

The power generation system 10 according to the present embodiment includes a power generation device (for example, a solar cell PV) and a power conversion system 1 that converts DC power generated by the solar cell PV into AC power and supplies it to the power system 8. The power conversion system 1 includes a power conversion device 2, a control device 5, and the like.

The power generation system 10 includes at least one solar cell PV. The solar cell PV is connected to the power conversion device 2. However, the number of solar cells PV is not limited to this. For example, FIG.
As shown in, the power generation system 10 may include a plurality of solar cell PVs. Similarly, when a plurality of solar cell PVs are included, each solar cell PV is connected to at least one power conversion device 2. In FIG. 1, the power generation system 10 has reference numerals 2a and 2b.
2, 2c, ... 2n includes n power conversion devices 2, but the number of power conversion devices 2 is not limited to this.

As described above, the power conversion device 2 converts the DC power transmitted from the solar cell PV into AC power, and supplies the converted AC power to the power system 8 and the load 11 connected to the power system 8. .. In the power conversion device 2, the function of converting DC power into AC power is carried by the DC / AC inverter circuit. Further, it is preferable that the power conversion device 2 includes a DC / DC converter circuit (boost circuit) that boosts the voltage of the DC power output from the solar cell PV to a predetermined value. The DC power boosted by the DC / DC converter circuit is supplied to the DC / AC inverter circuit. Further, the power conversion device 2 may also be connected to a power storage device that stores the power generated by the solar cell PV.

Each power converter 2 includes a DC / AC inverter circuit, a DC / DC converter circuit, and the like.
It is preferable to include a calculation unit, a communication unit, and the like. As will be described later, the power conversion device 2 suppresses the output power based on the control signal (first signal) or the like related to the output suppression from the control device 5. The power conversion device 2 receives the first signal to the control device 5 via the communication unit. In addition, the power converter 2
Processes the received first signal in the arithmetic unit and suppresses the output power.

Further, the power conversion device 2 is for transmitting the power generation value information of the connected solar cell PV and the power generation value from the solar cell PV when the power generation value from the solar cell PV becomes a predetermined value or less due to the setting of the sun or the like. It is preferable to have a function of transmitting information (second signal) to the control device 5. As a result, it is possible to promptly notify the control device 5 that power generation from the solar cell PV cannot be obtained, and power saving of the control device 5 and the system including the control device 5 (power conversion system 1, power generation system 10). Can be achieved. These functions are also realized by using the above-mentioned calculation unit and communication unit.

Further, in addition to the second signal generation function and transmission function, the power conversion device 2 transmits to the control device 5 when the power generated from the solar cell PV exceeds a predetermined value, for example, due to sunrise or the like. It may have a function of generating a third signal for this purpose and transmitting the third signal to the control device 5. As a result, the solar cell PV can recover the sufficient power generation function and immediately return to the state where the power can be output from the power conversion device 2. As a result, it is possible to prevent a situation in which the restart of the first signal is delayed even though there is already a sufficient amount of solar radiation, and it is possible to suppress the loss of the generated power and output it efficiently.

Next, the circuit configuration included in the power conversion device 2 according to the present embodiment will be described with reference to FIG. FIG. 2 is a schematic view of the wiring system of the power conversion device 2 according to the present embodiment. Specifically, it is a schematic diagram of a single-phase two-wire type power conversion circuit in the case where the solar cell PV (power generation device) is one system. However, when a plurality of other solar cell PVs such as the second system, the third system, the fourth system, and the nth system are provided, the configuration from the solar cell PV to the inverter circuit DA is the same as that of the first system. The second system, so that the circuits after the inverter circuit DA are common.
The third system, the fourth system, and the nth system are connected in parallel.

The DC power generated by the solar cell PV is supplied to the booster circuit BS. The booster circuit BS is composed of a chopper circuit including a DC reactor L1, a switching element S1, a diode D1, and a capacitor C1. By turning on / off the switching element S1 at a predetermined frequency, the input DC power voltage is applied. Boost to a predetermined voltage. The DC power boosted by the booster circuit BS is output to the inverter circuit DA.

The inverter circuit DA is a circuit in which a plurality of switching elements S2 to S5 are fully bridged. These switching elements S2 to S5 are periodically turned on / O by PWM control.
It is FF. As a result, it is converted into pseudo sine wave AC power synchronized with the frequency of the power system 8. The converted AC power is formed into a sinusoidal shape by attenuating high frequency components in a low-pass filter circuit LF composed of an AC reactor L2 and a capacitor C2. The AC power with the high frequency component attenuated is superimposed on the power system 8 via the relay contact RY.

The control circuit PC is composed of a microcomputer or the like, and controls the ON / OFF operation of the switching element S1 of the booster circuit BS and the switching elements S2 to S5 of the inverter circuit DA. also,
A switching circuit or the like for switching the DC supply of the solar cell PV is appropriately provided.

Further, the power conversion device 2 is connected to the control device 5. As shown in FIG. 1, when a plurality of power conversion devices 2 are provided, the control device 5 and the individual power conversion devices 2 may be connected to each other. In the connection form of the plurality of power conversion devices 2 and the control device 5, the individual power conversion devices 2 may be connected in series (serial form) to the control device 5, or may be connected in parallel. May be good.
However, it is preferable that the signals transmitted from the control device 5 are serial connections that are sequentially passed between the adjacent power conversion devices 2. In the case of serial connection, the control device 5 can transmit the information to all the power conversion devices 2 by transmitting a signal to one power conversion device 2 only once.
As an example of the serial connection, there is a mode in which the other power conversion devices 2b and 2c are sequentially connected in series to one power conversion device 2a directly connected to the control device 5.

Further, the control device 5 is connected to the power management server 3 as described above. Here, the electric power management server 3 is a server managed by an electric power company having jurisdiction over the electric power system 8 to which the power generation system 10 is connected. More specifically, the power management server 3 creates schedule information 7 for adjusting (suppressing) the output power from each power generation system connected to the power system 8, and transmits this to the control device 5. Alternatively, when there is an access for acquiring the schedule information 7 from the control device 5, the power management server 3 may respond and transmit the schedule information 7 to the control device 5.

The control device 5 controls so as to suppress the output power of all the power conversion devices connected to the control device 5. More specifically, based on the schedule information 7 transmitted from the power management server 3, the control device 5 transmits a first signal based on the suppression information for suppressing the output power to each power conversion device 2.

An example of the schedule information 7 transmitted from the power management server 3 will be described with reference to FIG. The schedule information 7 includes, for example, an upper limit value of the output power in each power generation system 10 and
Includes the time zone (time) when the upper limit is implemented. The unit of the upper limit value of the output power is a percentage of the maximum output power that can be output from each power generation system 10.

The schedule information 7 in this embodiment is transmitted from the power management server 3 to each power generation system 10. It should be noted that the schedule may be set for each power conversion device of each power generation system 10. However, the method of transmitting the schedule information 7 is not limited to this.
The example shown in FIG. 3 shows a daily power suppression schedule, but the schedule information 7 may include a schedule for a plurality of days. For example, schedule information 7
May include a one-month suppression schedule generated for each power generation system.

As shown in FIG. 3, the schedule information 7 transmitted from the power management server 3 usually includes output control information at night. That is, if no restriction is set, the control device 5 that has received the schedule information 7 transmits the first signal to the power conversion device 2 even at night when power generation from the solar cell PV cannot be obtained. Become. In this case, the control device 5 always keeps transmitting the first signal to the power conversion device 2 even though the generated power is not substantially supplied from the power conversion device 2 to the power system 8 or the like. In order to avoid such a situation, the control device 5 includes means for stopping the transmission of the first signal when the power generated from the solar cell PV becomes a predetermined value or less (details will be described later).

Next, the hardware configuration of the control device 5 will be described with reference to FIG. As shown in FIG. 4, the control device 5 includes a calculation unit 51, a memory unit 52, a storage unit 53, and a communication unit 54.
Also, these hardware are interconnected by an internal bus 55. The control device 5 communicates with the power conversion device 2 and the power management server 3 via the communication unit 54.

The calculation unit 51 is, for example, a Central Processing Unit (hereinafter, ""
CPU ”), and the memory unit 52 is, for example, Random Access Memory.
y (hereinafter, “RAM”), and the storage unit 53 is, for example, Read Only Memo.
It is a ry (hereinafter, “ROM”), a hard disk drive, or the like. Here, the memory unit 52 functions as a work area of the calculation unit 51, and the storage unit 53 stores programs and data for performing various information processing.

Depending on the hardware and the software installed therein, the control device 5 functions, for example, to include the following means.
(1) Means for transmitting / receiving information (signals) to / from the power management server 3, the power conversion device 2, and other electrically connected devices (for example, the schedule information 7 transmitted from the power management server 3). Reception, transmission / reception of information related to reception of the first signal to the power conversion device 2, reception of the second signal from the power conversion device 2, etc.).
(2) A means for stopping the transmission of the first signal to the power conversion device 2 in response to the reception of the second signal from the power conversion device 2.
Of course, the means provided in the control device 5 is not limited to the above. The control device 5 may include other means.
Other means include, for example, the following.
(3) For example, when the third signal transmitted from the power conversion device 2 is received when the generated power from the solar cell PV exceeds a predetermined value due to sunrise or the like, the first signal is transmitted to the power conversion device 2. Means to resume.

The threshold value of the generated power related to the generation / transmission of the second signal and the third signal can be arbitrarily set. As an example, it is conceivable to generate and transmit the second signal and the third signal when the maximum output value of the solar cell PV (power conversion device 2) becomes 1 to 10%. In addition, the threshold value may be appropriately changed based on the weather information of the day expected in advance. Further, by combining these, at least one of the control device 5 and the power conversion device 2 may calculate the threshold value (for example, on a day when sunny weather is expected, the maximum output value of the solar cell PV (power conversion device 2). The threshold value is 1 to 10% of the above value, but on days when cloudy weather or rain is expected, a value larger than the above value, for example, 5 to 15% may be set as the threshold value.) The threshold value may be set by using the same numerical value at all times, or may be changed only at an appropriate timing.

As shown in FIG. 1, the control device 5 may be connected to the power management server 3 via the communication modem 6. Further, the control device 5 may be connected to the monitor device 9. The monitor device 9 is for monitoring the operating state of the control device 5, and is input via a display unit such as a display and an input unit such as a keyboard or mouse, a communication unit, an input unit, or a communication unit. It is preferable to include a calculation unit or the like that performs calculations based on various types of information. Further, the control device 5 (and / or the power conversion device 2) may be connected to a weather forecast server or the like that predicts the weather on any day. It can also function as a remote controller for instructing the setting and operation of the control device 5 and the power conversion device 2.

For example, when the power generation system 10 according to the present embodiment is installed in a house, HEMS (Home E) used for remotely controlling an electric device (household load) 11 in the home.
A controller 12 called a nerve Management System) may be provided. In this embodiment, the controller 12 is connected to the communication modem 6 as shown in FIG. In addition, when the power generation system 10 is installed in a commercial building, a factory, or the like, the communication modem 6 is a BEMS (Billing Energy Manag).
element System) and FEMS (Factory Energy Management)
It may be provided with an element system).

Next, the operation flow of the control device 5 and the power conversion device 2 will be described with reference to FIG. Figure 5
Is a sequence diagram showing the operation of the control device 5 and the power conversion device 2 according to the present embodiment.
First, the control device 5 receives the schedule information 7 transmitted from the power management server 3, and based on the schedule information 7, converts the output power suppression control signal (first signal) into the power conversion device 2.
Send to.

Prior to transmitting the first signal to the power conversion device 2, the control device 5 sends a confirmation signal to the power conversion device 2 in order to confirm whether or not communication with the power conversion device 2 is possible. Is preferred. When there is a response signal from the power conversion device 2 to the confirmation signal, the control device 5 determines that communication with the power conversion device 2 is possible. Along with that, the control device 5
Transmits the first signal to the power converter 2. The control device 5 is set at predetermined intervals (for example, at predetermined intervals (for example).
The first signal is periodically transmitted to the power converter 2 every minute).

Next, when the power conversion device 2 detects that the amount of power generated by the solar cell PV is equal to or less than a predetermined value (predetermined threshold value) due to a situation such as sunset, the power conversion device 2 causes the power conversion device 2. , Generates a second signal containing information to that effect. Finally, the power converter 2 generated a second
The signal is transmitted to the control device 5.

The control device 5 that has received the second signal stops the first signal that has been transmitted to the power conversion device 2. As a result, the first signal is not transmitted from the control device 5 to the power conversion device 2 thereafter, so that unnecessary operation of the control device 5 can be prevented.

Next, when the power conversion device 2 detects that the amount of power generated by the solar cell PV exceeds a predetermined value due to a situation such as sunrise, the power conversion device 2 provides information to that effect. Generates a third signal that includes. Finally, the power conversion device 2 transmits the generated third signal to the control device 5.

The control device 5 that has received the third signal resumes the transmission of the first signal that has been stopped. After that, the control device 5 periodically transmits the first signal to the power conversion device 2 until the next second signal is received from the power conversion device 2.

Although one embodiment of the present invention has been described above, the above description is for facilitating the understanding of the present invention and does not limit the present invention. It goes without saying that the present invention can be modified and improved without departing from the spirit thereof, and the present invention includes its equivalents.

For example, the amount of power generated by the solar cell PV is directly determined when the amount of power generated by the solar cell PV is equal to or less than a predetermined value (predetermined threshold value) for sunset or sunrise, but it may be determined indirectly. Specifically, when the power generated by the solar cell is sufficient (when the amount of power generated by the solar cell PV exceeds a predetermined value (predetermined threshold value) at sunrise or the like), the power conversion device 2 is connected to the power system 8. When the system is connected, the relay RY is closed and connected. Conversely, when the power generated by the solar cell is insufficient (when the power generated by the solar cell is below a predetermined threshold due to sunset, etc.), the relay RY is opened to generate power. It utilizes the disconnection between the converter 2 and the power system.

That is, after detecting that the relay RY has changed from the closed state to the open state, it is determined that the generated power of the solar cell is sufficient, and the power conversion device 2 may transmit the second signal to the control device 5. .. Similarly, when the relay RY changes from the open state to the closed state, the third signal may be transmitted from the power conversion device 2 to the control device 5.

Further, it is desirable that the second signal is transmitted to the control device 5 after the relay is opened. When the power conversion device 2 performs the suppression operation based on the schedule from the server, the schedule information cannot be obtained or the control signal based on the schedule information (the first signal in the present embodiment) cannot be obtained (that is, the first signal). For safety (to suppress system voltage rise)
Designed to stop working. If the second signal is transmitted before the relay opens, even if the power converter 2 tries to continue the operation, it may detect a communication interruption and stop the operation. Therefore, after the relay opens, the second signal is transmitted. Such a situation can be suppressed by transmitting two signals.

Similarly, it is desirable that the third signal be transmitted to the control device 5 before the relay is closed.
As a result, the control device 5 can resume the transmission of the first signal before the relay is closed or immediately after the relay is closed (before the communication blackout is detected), so that the power conversion device 2 can be used. The operation can be pending without detecting a communication interruption. It is desirable to transmit before the relay closes, but as described above, it is sufficient if the first signal can be transmitted before the communication blackout is detected on the power conversion device 2 side, so it seems that it will be in time. If so, the third signal may be transmitted immediately after the relay is closed.

Further, in the present embodiment, the power conversion device 2 side determines whether or not the output of the solar cell PV can sufficiently obtain the generated power of the solar cell PV, but the control device 5 side may determine. Specifically, the maximum power that can be output from the solar cell PV is set in advance on the control device 5 side, and the power generated by the solar cell PV (may be information on the output current) from the power conversion device 2 is periodically set. It is transmitted to the control device 5. The control device 5 compares the maximum power with the generated power, and determines whether or not the output of the solar cell PV can sufficiently obtain the generated power of the solar cell PV.

1 ・ ・ ・ ・ ・ ・ ・ ・ Power conversion system 2 ・ ・ ・ ・ ・ ・ ・ ・ Power conversion device (power conditioner)
3 ・ ・ ・ ・ ・ ・ ・ ・ Power management server 5 ・ ・ ・ ・ ・ ・ ・ ・ Control device 6 ・ ・ ・ ・ ・ ・ ・ ・ Communication modem 10 ・ ・ ・ ・ ・ ・ ・ ・ Power generation system PV ・ ・ ・ ・ ・・ ・ Solar cell

Claims (5)

A power conversion device that converts the generated power of the solar cell into AC power and outputs the AC power to the power system and a server that transmits schedule information that suppresses the output power of the power conversion device are communicably connected.
The schedule information for suppressing the output power of the power conversion device is received from the server, and the first signal for controlling the output of the power conversion device generated based on the schedule information is periodically sent to the power conversion device. Send
A control device characterized in that transmission of the first signal is stopped when the generated power of the solar cell is equal to or less than a predetermined value. A second signal transmitted when the generated power of the solar cell is equal to or less than a predetermined value is received from the power conversion device, and the power conversion device receives the second signal.
The control device according to claim 1, wherein when the second signal is received, the transmission of the first signal is stopped. After stopping the transmission of the first signal, when the third signal transmitted from the power conversion device is received when the generated power of the solar cell exceeds a predetermined value, the first signal is sent to the power conversion device. The control device according to claim 2, wherein transmission is resumed. A power conversion device that converts the power generated by a solar cell into AC power and outputs the AC power to the power system.
The schedule information for suppressing the output of the power conversion device is received from the server, and the first signal for controlling the output of the power conversion device generated based on the schedule information is periodically transmitted to the power conversion device. Control device and
With
The control device is a power conversion system characterized in that transmission of the first signal is stopped when the generated power of the solar cell is equal to or less than a predetermined value. With solar cells
A power conversion device that converts the generated power of the solar cell into AC power and outputs the AC power to the power system.
The schedule information for suppressing the output of the power conversion device is received from the server, and the first signal generated based on the schedule information for controlling the output of the power conversion device is periodically transmitted to the power conversion device. Control device and
With
The control device is a power generation system characterized in that transmission of the first signal is stopped when the generated power of the solar cell is equal to or less than a predetermined value.

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