JP2022025226A - Output control device - Google Patents

Abstract

To enable a fluctuation prediction of a power supply amount to a power system by a photovoltaic power generation.SOLUTION: An output control device 4 is an output control device controlling an output to a power system of a power discharged from a storage battery storing a power generated by a power generation device generating a power by photovoltaic and the power generated by the power generation device, comprising: a conversion part 43 that converts the power to be generated into an AC power of a frequency in a predetermined first range in the case where the power generated by the power generation device can be supplied to the power system, and converts the power to be generated stored in the storage battery into an AC power of the frequency of a second range lower than a lower limit of the frequency of the first range in the case where the power to be generated cannot be supplied to the power system; and an output part 44 that outputs the AC power obtained by converting the frequency by the conversion part 43 to the power system.SELECTED DRAWING: Figure 2

Description

The present invention relates to an output control device that controls the output of electric power to an electric power system.

Conventionally, it is known to sell electric power generated by natural energy such as solar power generation or electric power stored in a storage battery (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-09537

Power generation by solar power generation depends on the weather. Therefore, when the power generated by many photovoltaic power generation facilities installed in the same area is supplied to the power system, the power from these power generation facilities to the power system is changed in response to changes in the weather. Supply may fluctuate rapidly. Existing power generation companies that have thermal power plants and supply power to the power system need to deal with sudden power fluctuations in the power system, which is a heavy burden. For this reason, existing power generation companies are required to predict fluctuations in the amount of power supplied to the power system due to photovoltaic power generation so that they can prepare in advance for fluctuations in the amount of power supplied.

Therefore, the present invention has been made in view of these points, and an object of the present invention is to provide an output control device capable of predicting fluctuations in the amount of power supplied to a power system by photovoltaic power generation.

The output control device according to the first aspect of the present invention controls the output of the electric power generated by the power generation device generated by sunlight and the electric power discharged from the storage battery that stores the electric power generated by the power generation device to the power system. When the generated power generated by the power generation device can be supplied to the power system, the generated power is converted into AC power having a frequency in a predetermined first range, and the power generation is performed. A conversion unit that converts the stored power stored in the storage battery into AC power having a frequency in the second range equal to or lower than the lower limit of the frequency in the first range when the power cannot be supplied to the power system, and the conversion unit. It is provided with an output unit for outputting the AC power whose frequency is converted by the above to the power system.

The output control device further includes a specific unit for specifying the stored amount in the storage battery, and the conversion unit is based on the stored amount specified by the specified unit when supplying the stored power to the power system. , The frequency of the AC power converted from the stored power may be changed.
When the stored power is supplied to the power system, the conversion unit may lower the frequency of the AC power converted from the stored power with the passage of time.

When supplying the stored power to the power system, the conversion unit may lower the frequency of the AC power converted from the stored power to the lower limit of the frequency allowed in the power system. ..

The conversion unit further includes a specific unit that specifies the amount of power generated by the power generation device, and the conversion unit uses the generated power based on the power generation amount specified by the specific unit when supplying the generated power to the power system. The frequency of the converted AC power may be changed.
When supplying the generated power to the power system, the conversion unit may increase the frequency of the AC power converted from the generated power as the amount of power generated specified by the specific unit is higher.

According to the present invention, there is an effect that it is possible to predict fluctuations in the amount of power supplied to the power system due to photovoltaic power generation.

It is a figure which shows the outline of the power supply system which concerns on this embodiment. It is a figure which shows the structure of the output control apparatus in this embodiment. It is a figure which shows the change example of the frequency of the AC power converted from the stored power which concerns on this embodiment. It is a flowchart which shows the flow of the process in the output control apparatus which concerns on this embodiment.

[Configuration of power supply system S]
FIG. 1 is a diagram showing an outline of the power supply system S according to the present embodiment. The power supply system S includes a power generation device 1, a storage battery 2, a charge / discharge control device 3, an output control device 4, and a power meter 5, and is provided with power generated by sunlight or power stored in the storage battery 2. Is a system for supplying power to the power system P. In the present embodiment, it is assumed that the load is not connected in the power supply system S, but the present invention is not limited to this. For example, one or more loads may be connected between the output control device 4 and the power meter 5. Further, in FIG. 1, one output control device 4 is connected to the power system P, but in reality, a plurality of output control devices 4 corresponding to each of the plurality of power generation devices 1 are connected to the power system P. It is assumed that it is connected.

The power generation device 1 is a power generation device that generates DC power by sunlight, and is, for example, a power generation facility having a solar panel. The power generation device 1 is connected to the storage battery 2 via the charge / discharge control device 3 and is also connected to the output control device 4. The power generation device 1 outputs the generated power to the storage battery 2 and the output control device 4.

The storage battery 2 is a device for storing electric power generated by the power generation device 1, and is, for example, a battery. The storage battery 2 stores the generated power output from the power generation device 1 according to the control of the charge / discharge control device 3, and discharges the stored power to the output control device 4.

The charge / discharge control device 3 is provided between the power generation device 1 and the storage battery 2, and based on the power generation status of the power generation device 1, the power generated by the power generation device 1 is stored in the storage battery 2 and the storage battery 2 is stored. The stored power stored in the output control device 4 is output to the output control device 4.

The output control device 4 is a device that converts the generated power generated by the power generation device 1 and the stored power stored in the storage battery 2 into AC power, and is, for example, a power conditioner. The output control device 4 supplies the AC power converted from the DC power to the power system P via the power meter 5.

When the output control device 4 can supply the generated power generated by the power generation device 1 or the stored power stored in the storage battery 2 to the power system P, the output control device 4 is based on the power generation amount in the power generation device 1 and the storage amount in the storage battery 2. The generated power and the stored power are converted into a frequency within a predetermined range allowed in the power system P and output. By doing so, the frequency of the power system P varies depending on the amount of power generation in the power generation device 1 and the amount of storage in the storage battery 2. As a result, the existing power generation company that supplies power to the power system P can predict the fluctuation of the power supply amount to the power system P by the power generation device 1 based on the frequency fluctuation of the AC power in the power system P. can.

The power meter 5 is provided between the output control device 4 and the power system P, and measures the amount of AC power output from the output control device 4 to the power system P. Since the power meter 5 is provided, the amount of power supplied from the power supply system S to the power system P can be easily specified.

[Configuration of output control device 4]
Subsequently, the configuration of the output control device 4 will be described. FIG. 2 is a diagram showing the configuration of the output control device 4 in the present embodiment. As shown in FIG. 2, the output control device 4 includes a communication unit 41, an input unit 42, a conversion unit 43, an output unit 44, a storage unit 45, and a control unit 46.

The communication unit 41 is, for example, a power meter (not shown) for measuring the amount of power generated by the power generation device 1, an ammeter (not shown) for measuring the current input to / from the storage battery 2, and a charge / discharge control device 3. It is a communication interface for communicating with.

The input unit 42 is an input terminal that receives the input of DC power output from the power generation device 1 and the storage battery 2.
The conversion unit 43 is, for example, an inverter that converts the DC power input to the input unit 42 into AC power.
The output unit 44 is an output terminal that outputs AC power converted by the conversion unit 43. The output unit 44 outputs the AC power whose frequency has been converted by the conversion unit 43 to the power system P via the power meter 5.

The storage unit 45 is a storage medium including, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit 45 stores a program executed by the control unit 46. For example, the storage unit 45 stores an output control program that causes the control unit 46 to function as the specific unit 461 and the output control unit 462.

The control unit 46 is, for example, a CPU (Central Processing Unit). The control unit 46 functions as the specific unit 461 and the output control unit 462 by executing the output control program stored in the storage unit 45.

The specifying unit 461 specifies the amount of power generated by the power generation device 1. For example, the specific unit 461 acquires the information indicating the power generation amount of the power generation device 1 measured by the power system from the power meter (not shown) provided in the power generation device 1, thereby generating the power generation amount of the power generation device 1. To identify.

Further, the specifying unit 461 specifies the amount of electricity stored in the storage battery 2. For example, the specific unit 461 is a current value when the storage battery 2 is charged as measured by an ammeter (not shown) provided between the storage battery 2 and the charge / discharge control device 3, and discharge from the storage battery 2. Acquires information indicating the current value when is performed. Based on the acquired information, the specific unit 461 calculates a current integrated value when the storage battery 2 is charged and a current integrated value when the storage battery 2 is discharged. Then, the specifying unit 461 specifies the SOC (State Of Charge) as information indicating the amount of stored electricity, based on the calculated current integrated value and the discharge capacity of the storage battery 2.

The output control unit 462 converts the generated power generated by the power generation device 1 and the stored power stored in the storage battery 2 into a frequency within a predetermined range allowed in the power system P and outputs the power. First, the output control unit 462 can supply the generated power to the power system P or supply the stored power to the power system P based on the power generation amount in the power generation device 1 and the storage amount in the storage battery 2 specified by the specific unit 461. It is determined whether the generated power and the stored power can be supplied to the power system P. Here, the output control unit 462 can supply the generated power to the power system P when the amount of electricity stored in the storage battery 2 is equal to or greater than the predetermined amount of electricity and the amount of electricity generated by the power generation device 1 is equal to or greater than the predetermined amount of electricity. Is determined.

When the output control unit 462 can supply the generated power generated by the power generation device 1 to the power system P, the output control unit 462 controls the conversion unit 43, so that the conversion unit 43 has a first predetermined power generation. Convert to AC power with a range of frequencies.

Specifically, when the output control unit 462 supplies the generated power to the power system P, the output control unit 462 supplies the generated power to the conversion unit 43 in the first range of the reference frequency or higher predetermined in the power system P. Convert to AC power of frequency. Here, the reference frequency is, for example, 50.0 Hz. The upper limit of the first range is, for example, 50.3 Hz, which is the upper limit of the frequency allowed in the power system P. The lower limit of the first range is 50.0 Hz.

When the generated power can be supplied to the power system P, the output control unit 462 tells the conversion unit 43 the frequency of the AC power converted from the generated power based on the amount of power generated by the power generation device 1 specified by the specific unit 461. Change. For example, the output control unit 462 controls the conversion unit 43 to change the frequency of the AC power so that the frequency of the AC power becomes higher according to the increase in the amount of power generated by the power generation device 1.

For example, when the power generated by the plurality of power generation devices 1 becomes relatively large due to good weather, the plurality of output control devices 4 connected to the power generation devices 1 generate AC power having a frequency higher than the reference frequency. Output to system P. For example, when a plurality of power generation devices 1 are installed in the same area and the power generated by these power generation devices 1 has a large influence on the power system P, the plurality of output control devices 4 have frequencies higher than the reference frequency. By outputting the AC power of the above to the power system P, the frequency of the power in the power system P becomes high. This makes it possible to understand that the existing power generation company that supplies electric power to the electric power system P has a large amount of electric power supplied to the electric power system P. As a result, the power generation company can take early measures such as preparing to suppress the output of electric power in a thermal power plant or the like.

Further, when the output control unit 462 cannot supply the generated power to the power system P and can supply the stored power stored in the storage battery 2 to the power system P, the output control unit 43 controls the conversion unit 43 to control the conversion unit 43. In addition, the stored power is converted into AC power having a frequency in the second range, which is equal to or less than the lower limit of the frequency in the first range.

Specifically, when the output control unit 462 cannot supply the generated power to the power system P and can supply the stored power to the power system P, the power stored in the conversion unit 43 is predetermined in the power system P. It is converted into AC power having a frequency in the second range below the reference frequency. Here, the upper limit of the second range is, for example, 50.0 Hz. The lower limit of the second range is, for example, 49.7 Hz, which is the lower limit of the frequency allowed in the power system P.

When the output control unit 462 supplies the stored power to the power system P, the output control unit 462 changes the frequency of the AC power converted from the stored power to the conversion unit 43 based on the stored amount of the storage battery 2 specified by the specific unit 461. Let me.

FIG. 3 is a diagram showing an example of a change in the frequency of the AC power converted from the stored power according to the present embodiment. Here, the horizontal axis shown in FIG. 3 indicates the time, and the vertical axis indicates the frequency of the AC power. For example, the output control unit 462 supplies the generated power to the power system P by changing from fine weather to cloudy or rainy weather when the generated power can be supplied to the power system P and the stored power can be supplied to the power system P. When the state changes to the impossible state, the conversion of the stored power to the AC power is started by controlling the conversion unit 43.

At time T0 shown in FIG. 3, the frequency of the AC power converted from the stored power is the upper limit of the second range, that is, 50.0 Hz. After that, when the stored power is supplied to the power system P, the output control unit 462 controls the conversion unit 43 to lower the frequency of the AC power converted from the stored power with the passage of time. Then, when the storage power is supplied to the power system P, the conversion unit 43 finally sets the frequency of the AC power converted from the stored power to the lower limit of the frequency allowed in the power system P (49. 7Hz).

After that, the output control unit 462 controls so that the power is not output from the output control device 4 to the power system P. In the example shown in FIG. 3, it can be confirmed that at time T1, the frequency of the AC power converted from the stored power drops to 49.7 Hz, and then the power supply is stopped.

For example, when the weather changes from fine weather to cloudy or rainy weather and it is expected that the power generated by the plurality of power generation devices 1 will be less than expected, the plurality of output control devices 4 connected to these power generation devices 1 will be referred to. Outputs AC power with a frequency lower than the frequency. For example, when a plurality of power generation devices 1 are installed in the same area and the power generated by these power generation devices 1 has a large influence on the power system P, the plurality of output control devices 4 have frequencies lower than the reference frequency. By outputting the AC power of the above to the power system P, the frequency of the power in the power system P becomes low. This makes it possible to understand that the amount of power supplied to the power system P is low in the existing power generation company that supplies power to the power system P. As a result, the power generation company can take early measures such as preparing to increase the output of electric power in a thermal power plant or the like.

When the output control unit 462 changes from the case where the generated power cannot be supplied to the power system P and the stored power can be supplied to the power system P to the state where the generated power can be supplied to the power system P, the generated power again. Conversion of stored power to AC power may be started. In this case, the output control unit 462 may use the frequency of the AC power converted from the generated power as the frequency of the AC power output immediately before the conversion from the generated power to the AC power is started.

[Process flow in output control device 4]
Subsequently, the flow of processing in the output control device 4 will be described. FIG. 4 is a flowchart showing a processing flow in the output control device 4 according to the present embodiment.

First, the specifying unit 461 specifies the amount of power generated by the power generation device 1 and the amount of electricity stored in the storage battery 2 (S1).
Subsequently, the output control unit 462 determines whether or not the generated power generated by the power generation device 1 can be output to the power system P based on the power generation amount and the storage amount specified by the specific unit 461 (S2). When the output control unit 462 determines that the generated power can be output to the power system P, the process is transferred to S3, and when it is determined that the generated power cannot be output to the power system P, the process is transferred to S4.

In S3, the output control unit 462 causes the conversion unit 43 to convert the generated power into AC power having a frequency in the first range and output it to the power system P based on the power generation amount specified by the specific unit 461. When the processing of S3 is completed, the output control unit 462 shifts the processing to S1.

In S4, the output control unit 462 determines whether or not the stored electric power stored in the storage battery 2 can be output to the power system P based on the stored amount specified by the specific unit 461. When the output control unit 462 determines that the stored power can be output to the power system P, the process is transferred to S5, and when it is determined that the generated power cannot be output to the power system P, the process is transferred to S1.

In S5, the output control unit 462 causes the conversion unit 43 to convert the stored power into AC power having a frequency in the second range based on the stored amount specified by the specific unit 461, and causes the power system P to output the stored power. When the processing of S5 is completed, the output control unit 462 shifts the processing to S1.

[Effects in this embodiment]
As described above, when the output control device 4 according to the present embodiment can supply the generated power generated by the power generation device 1 to the power system P, the generated power has a predetermined frequency in the first range. When the generated power cannot be supplied to the power system P, the stored power stored in the storage battery 2 is converted into AC power having a frequency in the second range below the lower limit of the frequency in the first range. , The AC power is output to the power system P. By doing so, the frequency of the power system P varies depending on the amount of power generation in the power generation device 1 and the amount of storage in the storage battery 2. As a result, other power generation companies and the like that supply power to the power system P can predict fluctuations in the amount of power supplied to the power system by the power generation device 1 that performs solar power generation.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes can be made within the scope of the gist. be. For example, all or part of the device can be functionally or physically distributed / integrated in any unit. Also included in the embodiments of the present invention are new embodiments resulting from any combination of the plurality of embodiments. The effect of the new embodiment produced by the combination has the effect of the original embodiment together.

1 ... Power generation device, 2 ... Storage battery, 3 ... Charge / discharge control device, 4 ... Output control device, 41 ... Communication unit, 42 ... Input unit, 43 ... Conversion unit , 44 ... Output unit, 45 ... Storage unit, 46 ... Control unit, 461 ... Specific unit, 462 ... Output control unit, 5 ... Power meter, P ... Power system

Claims (6)

It is an output control device that controls the output of the electric power generated by the power generation device generated by sunlight and the electric power discharged from the storage battery that stores the electric power generated by the power generation device to the power system.
When the generated power generated by the power generation device can be supplied to the power system, the generated power cannot be converted into AC power having a predetermined frequency in the first range, and the generated power cannot be supplied to the power system. In this case, a conversion unit that converts the stored power stored in the storage battery into AC power having a frequency in the second range equal to or less than the lower limit of the frequency in the first range.
An output unit that outputs the AC power whose frequency has been converted by the conversion unit to the power system, and an output unit.
Output control unit equipped with. Further provided with a specific unit for specifying the amount of electricity stored in the storage battery,
When the stored power is supplied to the power system, the conversion unit changes the frequency of the AC power converted from the stored power based on the stored amount specified by the specific unit.
The output control device according to claim 1. When the stored power is supplied to the power system, the conversion unit lowers the frequency of the AC power converted from the stored power with the passage of time.
The output control device according to claim 2. The conversion unit lowers the frequency of the AC power converted from the stored power to the lower limit of the frequency allowed in the power system when the stored power is supplied to the power system.
The output control device according to claim 3. Further provided with a specific unit for specifying the amount of power generated by the power generation device,
When the generated power is supplied to the power system, the conversion unit changes the frequency of the AC power converted from the generated power based on the power generation amount specified by the specific unit.
The output control device according to any one of claims 1 to 4. When the conversion unit supplies the generated power to the power system, the higher the power generation amount specified by the specific unit, the higher the frequency of the AC power converted from the generated power.
The output control device according to claim 5.

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