JP2016052192A - Independent power supply system and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an independent power supply system and control method thereof, capable of reducing an operation cost.SOLUTION: The independent power supply system includes: a pyranometer for measuring the quantity of solar radiation; a battery; a photovoltaic power generation section capable of generating electric power through sunlight and supplying the power to a load; and a control section for controlling the supply of electric power from the battery, on the basis of the quantity of solar radiation acquired from the pyranometer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an independent power supply system and a control method for the independent power supply system.

  An independent power supply system using a solar power generation device, a storage battery, and a fuel cell is known. Such an independent power supply system is used as a power source for a weather observation device, a communication device, etc., for example, in a non-power supply zone such as a mountain or a remote island. In general, the independent power supply system is often operated in an unattended state. When the operation is started after the installation, it is used without maintenance until the battery replacement time.

  In Patent Document 1, for example, a photovoltaic power generation system installed in a building such as a house, a management center equipped with a natural energy amount prediction device, and various weather data relating to meteorological phenomena that affect the amount of solar radiation that is natural energy. And a meteorological data providing center for providing the information. In the technique described in Patent Document 1, the management center predicts the amount of solar radiation using data obtained from the weather data providing center, and the photovoltaic power generation system generates power using the prediction information provided from the management center. Calculate the quantity.

JP 2014-21555 A

  However, in the technique described in Patent Document 1, it is necessary to purchase weather data from a weather data providing center. As described above, in the technique described in Patent Document 1, since the photovoltaic power generation system is operated using the predicted value predicted by the natural energy amount prediction apparatus, the operation is costly. For this reason, when the independent power supply system is controlled using the technique described in Patent Document 1, there is a problem that the operation of the independent power supply system is expensive.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an independent power supply system and an independent power supply system control method capable of reducing operation costs.

  In view of the above-described problems, an independent power supply system according to an aspect of the present invention includes a pyranometer that measures the amount of solar radiation, a battery, a solar power generation unit that can generate power by sunlight and supply the load to the load, and the solar radiation meter A control unit that controls supply of electric power from the battery to the load based on the amount of solar radiation acquired from the battery.

Moreover, in the independent power supply system according to one aspect of the present invention, the control unit calculates the solar radiation intensity B (tx) at an arbitrary time (tx) in the daytime after sunrise using the solar radiation amount by the following formula: Predicted by
B (tx) = A (tx) × SB (to) / SA (to) (where A (tx) is the ideal daytime solar radiation intensity at the predicted time of day (tx), and SB (to) is from sunrise to present ( to (total) of measured solar radiation intensity until (to), SA (to) is the total value of ideal solar radiation intensity (calculated value) from sunrise to the present (to))
Calculate the solar radiation intensity B (tx) at any time (tx) at night using the following equation after sunset and before sunrise:
B (tx) = A (tx) × α (where α is greater than 0 and less than 1)
Using the calculated solar radiation intensity B (tx), the predicted generated power E (tx) is calculated by the following equation:
E (tx) = PV rating × ε (B (tx)) (where PV rating is the maximum generated power in the solar power generation unit, and ε (B (tx)) is the maximum when the solar radiation intensity is B (tx). Power generation efficiency)
Based on the calculated predicted generated power E (tx), the supply of power from the battery to the load may be controlled.

  Moreover, the independent power supply system which concerns on 1 aspect of this invention is equipped with the storage battery with which the electric power generated by the said photovoltaic power generation part is charged, The said control part is based on the calculated estimated generation electric power E (tx). The storage battery is controlled to be charged with the electric power generated by the solar power generation unit, and the load is applied to the load based on the calculated predicted generated power E (tx) and the capacity charged in the storage battery. You may make it control to supply the charged electric power.

  Moreover, the independent power supply system which concerns on 1 aspect of this invention WHEREIN: The said control part may be made to control so that supply of the electric power from the said battery to the said load may continue.

  An independent power supply system control method according to an aspect of the present invention includes a solar power meter that measures a solar radiation amount, a battery, and a solar power generation unit that can generate power by sunlight and supply the load to a load. The control method of the independent power supply system in the method, wherein the control unit acquires the amount of solar radiation measured by the pyranometer, and the control unit, based on the acquired amount of solar radiation, the power of the battery from the And a control procedure for controlling supply to the load.

  According to the present invention, the operation cost of the independent power supply system can be reduced.

It is a block diagram of the independent power supply system which concerns on this embodiment. It is a figure explaining the example of the value of monthly _PO and a in an atmospheric transmittance. It is a figure explaining the ideal sunny day solar radiation intensity and solar radiation intensity concerning this embodiment, and the figure explaining the electric power generation amount by a solar power generation device, the electric power supplied to load, insufficient electric power, and surplus electric power. It is a flowchart of the process sequence which the control part which concerns on this embodiment performs.

First, the outline of the present invention will be described.
The independent power supply system in the present embodiment includes a solar power generation device, a fuel cell, and a storage battery as will be described later. The storage battery is charged with the surplus of the power generated by the solar power generation device, and the charged power is used, for example, at night when solar power generation cannot be performed.

When the power charged in the storage battery alone cannot cover the power consumption of the load at night or the like, power is supplied from the fuel cell to the load. Fuel cells need to be replenished when power is used up. When the amount of power generated by sunlight is sufficient with respect to the load, the use of the fuel cell is stopped, so that the fuel can be held better, so that the period until the fuel is replaced can be extended.
For this reason, in this embodiment, the difference of the power consumption by load and the electric power generation amount by sunlight is estimated, and a fuel cell is controlled based on this prediction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of an independent power supply system 1 according to the present embodiment. As shown in FIG. 1, the independent power supply system 1 includes a solar power generation device 10, a fuel cell 20, a solar radiation meter 30, a control unit 40, a storage unit 50, a time measuring unit 60, and a storage battery 70. Solar power generation device 10, fuel cell 20, and storage battery 70 are connected to bus 80.

  The solar power generation device 10 receives sunlight to generate electric power, and supplies the generated electric power to the bus 80. The solar power generation device 10 includes a solar cell and a voltage conversion unit, for example. The solar cell converts solar light energy into electric power (direct current) and outputs the converted electric power to the voltage converter. The voltage conversion unit converts the voltage value of the electric power generated by the solar cell into a voltage value that matches the load. Note that the maximum power generation amount of the solar cell is, for example, about twice the power consumption of the load. By setting the capacity in this way, it is possible to supply the generated power to the load and generate surplus power during a period when the amount of solar radiation during the day is large.

The fuel cell 20 is started and stopped according to the control of the control unit 40. The fuel cell 20 supplies the generated power (direct current) to the bus 80. For example, when the power charged in the storage battery is used at night, the power of the fuel cell is used when the charged capacity is less than the power consumption of the load. The voltage value supplied to bus 80 is a voltage value that matches the load.
The solar radiation meter 30 measures the amount of solar radiation and outputs a value indicating the measured amount of solar radiation to the control unit 40.

  The control unit 40 calculates the ideal sunny day total solar radiation amount A using the information stored in the storage unit 50 and the time measurement result timed by the time measurement unit 60. The control unit 40 calculates the solar radiation intensity B (tx) at an arbitrary time (tx), using the calculated ideal total solar radiation amount A in clear weather and the value indicating the solar radiation amount input from the solar radiation meter. Based on the solar radiation intensity B (tx), the control unit 40 calculates the predicted generated power E (tx), which is the maximum power generated by the sunlight of the day, in time series. The control unit 40 controls the start and stop of use of the fuel cell 20 and the charge and discharge of the storage battery 70 based on the calculated predicted generated power E (tx). It should be noted that the ideal amount of solar radiation on a clear day is the amount of solar radiation on a clear day that is not affected by clouds or dust. The total solar radiation amount is the amount of all sunlight received by the ground surface. The control unit 40 supplies the generated power to the load via the bus 80 and, when there is a surplus in the generated power, controls to supply and charge the storage battery 70. Moreover, the control part 40 is controlled based on the electric power generation amount of the solar power generation device 10 and the remaining capacity of the storage battery 70 so that the time which supplies electric power from the fuel cell 20 to a load may continue.

  The storage unit 50 stores the power consumption of the load connected to the independent power supply system 1. The storage unit 50 stores information indicating a rating related to the amount of power generated by the solar battery of the solar power generation device 10. The storage unit 50 stores various types of information necessary for calculating the ideal sunny day total solar radiation amount A, solar radiation intensity B (tx), and predicted generated power E (tx). Various information will be described later. The storage unit 50 stores information regarding the sunshine hours of the place where the independent power supply system 1 is installed and information (latitude, longitude) of the place where the independent power system 1 is installed. Here, the information regarding the sunshine hours is information indicating the sunrise time and sunset time (sunset time) of each day of each month or one year of twelve months.

The time measuring unit 60 includes an oscillating unit, and measures a reference clock that is an oscillation signal oscillated by the oscillating unit. The timekeeping unit 60 outputs the timed time measurement result to the control unit 40. The time measurement result may be information indicating the date and time.
The storage battery 70 charges the power supplied from the bus 80 or supplies the charged power to the bus 80 according to the control of the control unit 40. The capacity of the storage battery 70 is, for example, about half of the power consumption of the load.
The electric power supplied to the bus 80 is supplied to the load.

<Total amount of solar radiation in ideal sunny weather>
Next, the calculation method of the ideal sunny day total solar radiation amount A performed by the control unit 40 will be described.
The control unit 40 calculates the solar radiation intensity outside the atmosphere at the place where the independent power supply system 1 is installed. The outdoor solar radiation intensity Io at the place where the independent power supply system 1 is installed may be stored in the storage unit 50 in advance. The atmospheric solar radiation intensity Io is the solar radiation intensity outside the atmosphere. The control unit 40 is a well-known method using the latitude and longitude of the installation location of the independent power supply system 1 stored in the storage unit 50, arbitrarily the solar declination at the date and time, the geocentric solar distance, the time difference, and the solar constant. To calculate the ambient solar radiation intensity Io.
Further, the control unit 40 uses the information stored in the storage unit 50 to calculate the atmospheric transmittance P as a correction parameter by the following equation (1).

Air permeability P = P ₀ + a (t [time] −12) ² (1)

In Equation (1), _PO is a constant that varies seasonally, and a is a constant that varies with time. t is the time and is a value from 0 to 24. An example of the values of _PO and a for each month is shown in FIG. FIG. 2 is a diagram for explaining an example of monthly _PO and a values in the atmospheric transmittance P (see Reference 1).

(Reference 1) “Building equipment basics”, Kenichi Kimura, International Institute for Human Environment, 2009, p265, https://setukiso.googlecode.com/files/Setukiso_vers.0.8.0.pdf (May 12, 2014 Day search)

  Next, the control unit 40 calculates an ideal sunny day total solar radiation amount A using the following equation (2).

Total sunny solar radiation amount A = Slope direct radiation amount + Slope scattered solar radiation amount + Slope reflected solar radiation amount (2)

  In equation (2), the direct solar radiation amount on the slope is expressed by the product of the direct solar radiation amount on the horizontal plane and the cosine of the incident angle on the slope as in the following equation (3). The slope reflected solar radiation amount is expressed as the following equation (5).

Slope direct solar radiation amount = horizontal direct solar radiation amount × cos (sunlight slope incident angle) / cos (π / 2−sun altitude) (3)

Slope scattered solar radiation amount = horizontal surface scattered solar radiation amount × (1 + cos (slope inclination angle)) / 2 (4)

Slope reflected solar radiation = (horizontal direct solar radiation + horizontal scattering solar radiation) × albedo × (1-cos (slope inclination angle)) / 2 (5)

  In equation (5), albedo is the ratio of the surface reflected light to the total solar radiation. Moreover, in Formula (3), a sunlight slope incident angle is an incident angle of the sunlight to a slope, and is represented like following Formula (6).

Sunlight incident angle = arccos (sin (solar altitude) cos (slope tilt angle) + cos (solar altitude) cos (solar azimuth angle) sin (slope tilt angle) cos (slope azimuth angle) + cos (solar altitude) sin (sun Azimuth) sin (slope slope angle) sin (slope azimuth angle)) (6)

  In equation (6), numerical values based on the conditions of the installation location are used for the slope inclination angle, slope azimuth angle, and point elevation. Further, in the equation (6), the solar azimuth angle is arcsin (sinA) when cosA is 0 or more, as shown in the following equation (7), the solar azimuth angle is arcsin (sinA), and when cosA is negative and sinA is 0 or more. In this case, the solar azimuth is π-arcsin (sinA), and when cosA is negative and sinA is negative, the solar azimuth is − (arcsin (sinA) + π).

Solar azimuth = IF (cosA> = 0, arcsin (sinA),
IF (sinA> = 0, π-arcsin (sinA), − (arcsin (sinA) + π))) (7)

  In equation (7), cosA is represented as the following equation (8), and sinA is represented as the following equation (9).

cosA = (sin (solar altitude) sin (latitude) −sin (sun declination)) / (cos (solar altitude) × cos (latitude)) (8)

sinA = cos (sun declination) sin (hour angle) / cos (solar altitude) (9)

  Moreover, in Formula (3) and Formula (5), a horizontal surface direct solar radiation amount is represented like following Formula (10).

Direct solar radiation level on the horizontal plane = Solar radiation level outside the atmospheric zone x Point atmospheric permeability coefficient (10)

In Expression (10), the solar radiation amount outside the atmosphere is the radiation energy from the sun received outside the Earth's atmosphere, and is expressed as the following equation (11) as a horizontal component of the solar constant. Note that the slope inclination angle in Equation (4) and the point atmospheric permeability coefficient in Equation (10) are specific to the place where they are installed, and also vary depending on the season and time. The solar constant is 1367 [W / m ² ]. In addition, in Formula (4) and Formula (6), the slope inclination angle is an angle inclined with respect to the horizontal plane.

Solar radiation level outside the atmospheric zone = solar constant x solar orbit distance ratio- ² x sin (solar altitude) (11)

  However, when the solar altitude is less than 0, the atmospheric solar radiation is 0. Moreover, in Formula (11), solar orbit distance ratio is represented like following Formula (12).

Solar orbit distance ratio = 1 / (1.00011 + 0.034221 × cos (ωj) + 0.00128 × sin (ωj) + 0.000719 × cos (2ωj) + 0.000077 × sin (2ωj)) ^0.5 ) (12 )

  In Expression (12), ωj is expressed as the following Expression (13).

ωj = sun orbit angle = 2π × total day / 365 (however, in case of leap year 366) (13)

  In equation (13), the total date is the date and time (daily conversion) from 0:00 on January 1 of the year. For example, if it is 12:00 on January 2, it is 1.5. Moreover, in Formula (11), solar altitude is represented like following Formula (14).

Solar altitude = arcsin (sin (latitude) × sin (sun declination) + cos (latitude) × cos (sun declination) × cos (hour angle)) (14)

  Further, in the equation (14), the solar declination is expressed as the following equation (15).

Solar declination = (0.33281-22.984 × cos (ωj) −0.3499 × cos (2ωj) −0.1398 × cos (3ωj) + 3.77872 × sin (ωj) + 0.0325 × sin (2ωj ) + 0.07187 × sin (3ωj)) × π / 180 (15)

  In the equation (14), the hour angle is expressed as the following equation (16). In Expression (16), the standard time is the time, and in the case of 30 minutes, it is 0, 0.5, 1.0, 1.5 to 23.0, 23.5 [hours].

Hour angle = (standard time−12 + time difference + equal time difference) × π / 12 (16)

Moreover, the numerical value based on the conditions of an installation location is used about the latitude and longitude in Formula (16).
Moreover, in Formula (16), a time difference is represented as following Formula (17), and a time difference is represented as following Formula (18).

Time difference = (longitude−135) /15=−0.0295 [hour] (17)

Time difference = 0.0072 × cos (ωj) −0.0528 × cos (2ωj) −0.0012 × cos (3ωj) −0.1229 × sin (ωj) −0.1565 × sin (2ωj) −0. 0041 × sin (3ωj) (18)

  Moreover, in Formula (4) and Formula (5), the horizontal-plane scattered solar radiation amount is expressed as the following Formula (19) by the Berlagage formula.

Horizontal plane scattered solar radiation = 0.5 × Solar orbit distance ratio ² × Solar constant × sin (solar altitude) × (1-atmospheric transmittance ^{point passing atmospheric mass} ) / (1-1.4 × ln (atmospheric transmittance)) ... (19)

  However, the amount of diffuse solar radiation after sunset is zero. In the equation (19), the point-passing atmospheric mass is expressed as the following equation (20).

Point passing air mass = (1 / (sin (solar altitude) + 0.15 × (solar altitude + 3.885) ^−1.253 )) × (1−spot altitude [m] / 44308) ^5.527 (20)

<Description of solar power generation forecasting method until sunset of the day>
The control unit 40 predicts the solar radiation intensity B (tx) [kW / m ² ] at an arbitrary time (tx) in the daytime after sunrise by calculation of the following equation (21).

B (tx) = A (tx) × SB (to) / SA (to) (21)

In equation (22), A (tx) is the ideal sunny solar radiation intensity (calculated value) [kW / m ² ] at the daytime predicted time (tx), and SB (to) is from sunrise to the present (to) The total measured solar radiation intensity [kWh / m ² ] and SA (to) is the total ideal solar radiation intensity (calculated value) [kWh / m ² ] from sunrise to the present (to). Based on the time measurement result of the time measuring unit 60, the control unit 40 reads information indicating the sunrise time and sunset time of the day at the place where the independent power supply system 1 is installed from the storage unit 50 and uses it for the calculation. The control unit 40 may calculate the sunrise time and the sunset time of the day using the solar altitude of the day stored in the storage unit 50.

When SA (to) is 0 or a value close to 0, the error is large in Expression (21). For this reason, when the present (to) is nighttime after sunset and before sunrise, the control unit 40 uses the following formula (22) to calculate the solar radiation intensity B (tx) [kW / m at an arbitrary time (tx) at nighttime. ² ] is calculated.

B (tx) = A (tx) × α (22)

In Expression (22), α is a numerical value (0 <α <1) determined in advance so that the independent power supply system 1 can be optimally operated.
Next, the control unit 40 calculates the predicted generated power E (tx) by the following equation (23) using the solar radiation intensity B (tx) calculated by the equation (21) or the equation (22).

E (tx) = PV rating × ε (B (tx)) (23)

In the formula (23), the PV rating is the maximum generated power when the panel temperature of the solar cell in the solar power generation apparatus 10 is 25 ° C. and the solar radiation intensity is 1 kW / m ² , and ε (B (tx)) is the solar radiation intensity. Is the maximum power generation efficiency when B is (tx), and these are determined in advance by actual measurement, for example.

  FIG. 3 is a diagram for explaining the ideal sunny day solar radiation intensity and solar radiation intensity according to the present embodiment, and for explaining the power generation amount by the photovoltaic power generation apparatus 10, the power supplied to the load, the insufficient power, and the surplus power. . FIG. 3 (a) is a diagram for explaining the ideal sunny day solar radiation intensity and solar radiation intensity, and FIG. 3 (b) illustrates the amount of power generated by the solar power generation apparatus 10, the power supplied to the load, the insufficient power, and the surplus power. It is a figure explaining an example. In the example shown in FIGS. 3A and 3B, the sunrise time is 6 o'clock and the sunset time (sunset time) is 18:00. In FIG. 3A, the horizontal axis is time, and the vertical axis is solar radiation intensity. In FIG. 3B, the horizontal axis is time, and the vertical axis is power.

  In FIG. 3 (a), a curve g101 is the ideal sunny day solar radiation intensity, and the area indicated by the symbol g111 is the ideal sunny day solar radiation from the sunrise to the present (to) in the formula (21) as the integrated value until each time. Indicates the total strength. The curve g102 is the solar radiation intensity, and the area indicated by the symbol g112 represents the total value of the actually measured solar radiation intensity from sunrise to the present (to) in the formula (21) as an integrated value up to each time. The control unit 40 predicts the solar radiation intensity B (tx) at an arbitrary time (tx) between 0 o'clock and 24 o'clock by calculating the ratio between the curve g101 and the curve g102 using the equation (21). The control unit 40 performs this prediction, for example, every 30 minutes.

In FIG. 3B, a curve p102 is the predicted generated power, and corresponds to the amount of power generated by the solar power generation device 10. A chain line p121 represents the power consumption of the load. The region indicated by the reference sign p131 indicates the power supplied to the load among the power generated by the solar power generation device 10 between time 6:00 and time 18:00. The areas indicated by reference signs p132 and p133 represent the shortage of the power generated by the solar power generation device 10 among the power supplied to the load from time 6:00 to time 8:00 and from time 15:00 to time 18:00. . A region indicated by reference sign p134 represents surplus power supplied to the load among the power generated by the solar power generation device 10 from time 8:00 to time 16:00.
That is, in the example shown in FIG. 3B, the period from time 6 o'clock to 8 o'clock and the period from time 16 o'clock to time 18 o'clock are only loads generated by the solar power generation device 10. This indicates that there is a shortage of power supplied to. The period from 8:00 to 16:00 indicates that the power can be supplied to the load only by the power generated by the solar power generation device 10. Further, the period from 8:00 to 16:00 represents that the remaining power supplied to the load among the generated power becomes surplus power. The controller 40 predicts the amount of power generated by the solar power generation device, thereby controlling the shortage to be supplied from other electric power and controlling the storage battery 70 to be charged with the surplus.

Next, a processing procedure performed by the control unit 40 will be described. FIG. 4 is a flowchart of a processing procedure including fuel cell control performed by the control unit 40 according to the present embodiment.
First, terms in FIG. 4 will be defined. tx, ty is the predicted time, to is the current time, Δt is the control time interval, SOC (to) is the current charge amount of the storage battery 70 (hereinafter referred to as the storage battery charge amount), and SOC (tx) is the predicted storage battery at the predicted time tx. The amount of charge. SOC (ty) is the predicted storage battery charge amount at the predicted time ty. SOCmin is the minimum charge amount of the storage battery 70 stored in advance in the storage unit 50 (hereinafter referred to as the minimum storage battery charge amount), and SOCmax is the maximum charge amount of the storage battery 70 stored in the storage unit 50 in advance (maximum). Storage battery charge amount), SE (tx) is the predicted maximum generated power amount from the present to the predicted time (tx), SE (ty) is the predicted maximum generated power amount from the present to the predicted time (ty), and SL (tx) is The predicted power consumption from the present to the predicted time (tx), SL (ty) is the predicted power consumption from the current to the predicted time (ty).
μc is the charging efficiency of the storage battery 70 from the bus 80 and μd is the discharge efficiency of the storage battery 70 to the bus 80, which is set in advance from experimental values and stored in the storage unit 50.

(Step S <b> 11) The control unit 40 calculates the current time to based on the timing information acquired from the timing unit 60, and acquires the current storage battery charge amount SOC (to) of the storage battery 70. Next, the control unit 40 sets the current time to at the predicted time tx, and sets the current storage battery charge SOC (to) to the storage battery charge SOC (tx) at the predicted time tx.

(Step S12) The control unit 40 determines whether or not the storage battery charge amount SOC (tx) at the predicted time tx is higher than the minimum storage battery charge amount SOCmin. When it is determined that the storage battery charge amount SOC (tx) at the predicted time tx is higher than the minimum storage battery charge amount SOCmin (step S12; YES), the control unit 40 proceeds to step S13, and the storage battery charge amount SOC at the predicted time tx. When it is determined that (tx) is not above the minimum storage battery charge amount SOCmin (step S12; NO), the process proceeds to step S22.

(Step S13) The control unit 40 determines whether or not the predicted time tx is less than a value obtained by adding 24 hours to the current time to. When it is determined that the predicted time tx is less than the value obtained by adding 24 hours to the current time to (step S13; YES), the control unit 40 proceeds to step S14, and the predicted time tx adds 24 hours to the current time to. When it is determined that the value is greater than or equal to the value (step S13; NO), the process proceeds to step S22. In the process of step S13, it is determined whether or not the prediction process for 24 hours from the current time to has been completed.

(Step S14) The control unit 40 substitutes a value obtained by adding the control time interval Δt to the predicted time tx to the predicted time ty. The control time interval Δt is, for example, 30 minutes.

(Step S15) The control unit 40 calculates the predicted maximum power generation amount from the predicted time tx to the predicted time ty using the formula (21) or the formula (22), and SE (tx) and SE (ty), respectively. Get. Further, predicted power consumption SL (tx) and SL (ty) from the present to the predicted time tx or the predicted time ty are calculated from the load data for each time stored in the storage unit 50. And the control part 40 calculates difference (DELTA) SE by calculating difference SE (ty) -SE (tx) from obtained prediction maximum electric power generation amount SE (tx) and SE (ty), and also predicting power consumption A difference SL (ty) −SL (tx) is calculated from the amounts SL (tx) and SL (ty) to calculate a difference ΔSL.

(Step S16) The control unit 40 compares the value of the difference ΔSE calculated in Step S15 with the value of the difference ΔSL. If the value of the difference ΔSE is equal to or larger than the value of the difference ΔSL (Step S16; YES), the process proceeds to Step S17. When the value of the difference ΔSE is less than the difference ΔSL (step S16; NO), the process proceeds to step S18.

(Step S17) The control unit 40 adds the surplus power, that is, the value of the difference ΔSE−the difference ΔSL multiplied by the charging efficiency μc to the SOC (tx), and sets the value as the SOC (ty).
(Step S18) The control unit 40 subtracts a value obtained by dividing the shortage power, that is, the value of ΔSL−ΔSE by the discharge efficiency from the SOC (tx), and sets the value as the predicted storage battery charge SOC (ty) at the predicted time ty.

(Step S19) The control unit 40 substitutes the predicted time ty into the predicted time tx, and substitutes the predicted storage battery charge amount SOC (ty) at the predicted time ty into the predicted storage battery charge amount SOC (tx) at the predicted time tx.

(Step S20) The control unit 40 determines whether or not the predicted storage battery charge amount SOC (tx) at the predicted time tx calculated in Step S5 is equal to or greater than the maximum storage battery charge amount SOCmax. When it is determined that the predicted storage battery charge amount SOC (tx) at the predicted time tx is greater than or equal to the maximum storage battery charge amount SOCmax (step S20: YES), the control unit 40 proceeds to step S21 and proceeds to the predicted storage battery charge amount at the predicted time tx. When it is determined that the SOC (tx) is less than the maximum storage battery charge amount SOCmax (step S20: NO), the process proceeds to step S12. That is, the control unit 40 proceeds to step S21 when the state of the storage battery 70 is fully charged, and proceeds to step S12 when the state of the storage battery 70 is not fully charged.

(Step S21) The control unit 40 performs control so that the fuel cell 20 is turned off, and ends the process.
(Step S22) The control unit 40 performs control so that the fuel cell 20 is turned on, and ends the process.
In addition, the control part 40 repeats the process of step S11 to step S22 for every control time interval (DELTA) t.

  According to the embodiment described above, since the operating state of the fuel cell 20 can be determined in advance by evaluating the storage battery charge amount based on the prediction, the fuel cell 20 can be used in a continuous time. It is also possible to perform control so that it is used efficiently.

  As described above, the independent power supply system 1 of the present embodiment includes a solar radiation meter 30 that measures the amount of solar radiation, a battery (fuel cell 20), and a solar power generation unit (solar power generation device) that generates power by sunlight. 10) and a control unit 40 that controls the supply of electric power from the battery to the load based on the amount of solar radiation acquired from the pyranometer.

  With this configuration, the independent power supply system 1 of the present embodiment controls the on state and the off state of the fuel cell 20 based on the amount of solar radiation measured by the solar radiation meter 30. Thereby, in this embodiment, it can control to use the fuel of the fuel cell 20 efficiently by controlling the fuel cell 20 based on the amount of solar radiation. As a result, according to the present embodiment, the operation cost of the independent power supply system can be reduced.

Some fuel cells cannot start supplying power for a certain period of time, for example, 3 hours after being stopped. In this case, for example, even if an attempt is made to switch the fuel cell 20 between the on state and the off state every 30 minutes, the fuel cell 20 cannot be switched on for 3 hours after switching from the on state to the off state. Therefore, the control for turning off the fuel cell is performed after measuring a sufficient amount of solar radiation after sunrise in order to increase the prediction accuracy of the amount of solar radiation. In other words, the control to turn off is not performed until the predicted amount of solar radiation in ideal sunny weather exceeds 1% of the total amount of solar radiation per day.
Thus, according to the present embodiment, after the fuel cell 20 is controlled to be in the off state, it is predicted that the power supplied to the load will not be insufficient during the day. There is no control to the on state. As a result, according to the present embodiment, since the fuel cell 20 can be used in a continuous time, it can be controlled to use the fuel of the fuel cell 20 efficiently.

  In the present embodiment, the example in which the independent power supply system 1 includes the fuel cell 20 as an auxiliary battery has been described, but the present invention is not limited thereto. The auxiliary battery included in the independent power supply system 1 only needs to be able to control the supply and stop of power to the load by the control unit 40, and may be another battery.

A program for realizing all or part of the functions of the independent power supply system 1 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into the computer system and executed. You may perform the process of each part. Here, the “computer system” includes an OS and hardware such as peripheral devices.
Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention.

1 independent power supply system, 10 solar power generation device, 20 fuel cell, 30 pyranometer, 40 control unit, 50 storage unit, 60 timing unit, 70 storage battery, 80 bus

Claims (5)

A pyranometer to measure the amount of solar radiation;
Battery,
A solar power generation unit capable of generating electric power by sunlight and supplying it to a load;
Based on the amount of solar radiation acquired from the pyranometer, a control unit that controls the supply of power from the battery to the load;
Independent power system. The controller is
Using the amount of solar radiation, the solar radiation intensity B (tx) at the predicted time (tx) in the daytime after sunrise is predicted by calculating the following equation:
B (tx) = A (tx) × SB (to) / SA (to)
(However, A (tx) is the ideal daytime solar radiation intensity at the daytime predicted time (tx), SB (to) is the total measured solar radiation intensity from sunrise to the present (to), and SA (to) is the current from the sunrise. (Total value of ideal solar radiation intensity (calculated value) up to (to))
Calculate the solar radiation intensity B (tx) at the predicted night time (tx) using the following formula at night after sunset and before sunrise:
B (tx) = A (tx) × α
(Where α is greater than 0 and less than 1)
Using the calculated solar radiation intensity B (tx), the predicted generated power E (tx) is calculated by the following equation:
E (tx) = PV rating × ε (B (tx))
(However, PV rating is the maximum generated power in the solar power generation section, and ε (B (tx)) is the maximum power generation efficiency when the solar radiation intensity is B (tx)).
The independent power supply system according to claim 1, wherein supply of power from the battery to the load is controlled based on the calculated predicted generated power E (tx). A storage battery charged with the electric power generated by the solar power generation unit,
The controller is
Based on the calculated predicted generated power E (tx), the storage battery is controlled to be charged with the power generated by the solar power generation unit, and the calculated predicted generated power E (tx) and the storage battery are charged. The independent power supply system according to claim 2, wherein control is performed so as to supply the charged power to the load based on a capacity to be performed. The controller is
The independent power supply system according to any one of claims 1 to 3, wherein control is performed so that power supply from the battery to the load is continuous. A control method for an independent power supply system in an independent power supply system having a solar radiation meter for measuring the amount of solar radiation, a battery, and a solar power generation unit capable of generating electric power by sunlight and supplying it to a load,
The control unit obtains the amount of solar radiation measured by the pyranometer,
The control unit controls the supply of power from the battery to the load based on the acquired amount of solar radiation,
Control method for an independent power supply system including:

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