WO2022259778A1 - 平滑化目標値算出装置、電力供給システム、平滑化目標値算出方法及びプログラム - Google Patents
平滑化目標値算出装置、電力供給システム、平滑化目標値算出方法及びプログラム Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
Definitions
- the present disclosure relates to a smoothing target value calculation device, a power supply system, a smoothing target value calculation method, and a program.
- Patent Document 1 the power generated by renewable energy is predicted, and the power obtained by combining the predicted value of the generated power and the charge and discharge power from the secondary battery is set as a target value, and the fluctuation is within a predetermined range.
- a method is disclosed for controlling the charging and discharging of a secondary battery in a controlled manner.
- the present disclosure provides a smoothing target value calculation device, a power supply system, a smoothing target value calculation method, and a program that can solve the above problems.
- the smoothing target value calculation device is a target value of the power obtained by adding the first power generated by the renewable energy power generation system and the second power charged and discharged by the battery.
- a smoothed target value calculation device for calculating a value comprising: a predicted value acquisition unit that acquires a predicted value of the first electric power; a predicted value correction unit that corrects the predicted value; and a smoothing target value calculation unit that calculates the smoothing target value by smoothing.
- the smoothing target value calculation device is a target value of the power obtained by adding the first power generated by the renewable energy power generation system and the second power charged and discharged by the battery.
- a smoothed target value calculation device for calculating a value comprising a method selection unit that selects a method for calculating the smoothed target value, wherein the method selection unit selects the predicted value of the first power for one day If the sum exceeds a threshold, select a method of calculating the smoothed target value by smoothing the predicted value; A method of calculating the smoothed target value by calculating the moving average value of the actual value of electric power is selected.
- the power supply system of the present disclosure includes a renewable energy power generation system, a battery system that charges and discharges a battery to compensate for output fluctuations of the renewable energy power generation system, and any of the above smoothed target value calculation devices. and the battery system charges and discharges the battery based on the difference between the smoothing target value calculated by the smoothing target value calculation device and the power generated by the renewable energy power generation system.
- the smoothing target value calculation method of the present disclosure calculates a smoothing target value that is a target value of power that is the sum of the first power generated by the renewable energy power generation system and the second power that is charged and discharged by the battery.
- a target value calculation method comprising: obtaining a predicted value of the first electric power; correcting the predicted value; and smoothing the corrected predicted value to calculate the smoothed target value.
- the program of the present disclosure causes a computer to calculate a smoothed target value, which is a target value of power that is the sum of the first power generated by the renewable energy power generation system and the second power that is charged and discharged by the battery.
- a step of acquiring a predicted value, a step of correcting the predicted value, and a step of smoothing the corrected predicted value to calculate the smoothed target value are executed.
- smoothing target value calculation device power supply system, smoothing target value calculation method, and program described above, deterioration of the secondary battery can be suppressed while suppressing output fluctuations in renewable energy power generation.
- FIG. 10 is a first diagram for explaining the relationship between the magnitude of PV power and fluctuations in PV power in relation to the third embodiment;
- FIG. 11 is a second diagram for explaining the relationship between the magnitude of PV power and fluctuations in PV power in relation to the third embodiment.
- FIG. 1 The power supply system 100 of the present disclosure will be described below with reference to FIGS. 1 to 10.
- FIG. 1 the same reference numerals are given to components having the same or similar functions. Duplicate descriptions of these configurations may be omitted.
- FIG. 1 is a diagram illustrating an example of a power supply system according to an embodiment.
- the power supply system 100 includes a renewable energy power generation system 1 such as solar power, wind power, hydraulic power, geothermal power and biomass power, and a smoothing system 2 .
- the smoothing system 2 smoothes fluctuations in the output (generated power) of the renewable energy power generation system 1 .
- the power supply system 100 supplies the power generated by the renewable energy power generation system 1 and smoothed by the smoothing system 2 to loads such as facilities such as factories and commercial power systems.
- the smoothing system 2 includes a prediction system 3 , a smoothing target value calculation device 10 and a battery system 4 .
- the prediction system 3 predicts the power that the renewable energy power generation system 1 will generate in the future, based on the actual value of the power that the renewable energy power generation system 1 has generated in the past.
- the power generated by the renewable energy power generation system 1 is abbreviated as PV power (PV is an abbreviation for Photovoltaic, but the scope of application of the present disclosure is not limited to photovoltaic power generation), and the amount of power is abbreviated as PV power. do.
- the prediction system 3 uses the actual value of PV power in a certain time period in the past (one day ago, one week ago, etc.) as an explanatory variable, and the actual value of PV power in the same time period on another day as an objective variable.
- the prediction system 3 has a prediction model 31 that learns the relationship between the two by random forest or the like. Using this prediction model 31, the prediction system 3 predicts the PV power for each corresponding hour on the current day from the actual value of the PV power for each predetermined time in the past (for example, every 30 minutes on the previous day). At the end of the day, the prediction system 3 predicts the amount of PV power for the next day based on the total amount of PV power generated on that day.
- the smoothing target value calculation device 10 acquires the predicted value of PV power predicted by the prediction system 3 from the prediction system 3 and acquires the actual value of PV power from the renewable energy power generation system 1 .
- the smoothing target value calculation device 10 calculates the target value of the power supplied to the load by the power supply system 100 by correcting the predicted value of the PV power based on the actual value of the PV power. This target value is called a smoothing target value.
- the battery system 4 is a BESS (Battery Energy Storage System).
- the battery system 4 plays a role of absorbing and stabilizing output fluctuations of the renewable energy power generation system 1 .
- Battery system 4 includes a battery 41 and a control device 42 .
- Batteries 41 are one or more secondary batteries such as lithium batteries or lead batteries.
- the control device 42 performs charge/discharge control of the battery 41 and monitors SOC (State Of Charge, charging rate).
- the control device 42 acquires a charge/discharge command value from the smoothing target value calculation device 10, and controls charging/discharging of the battery 41 so that the power supplied to the load from the power supply system 100 reaches the smoothing target value. .
- the control device 42 controls charging and discharging of the battery 41 so that the SOC of the battery 41 becomes a predetermined target value (eg, 50%).
- the smoothed target value calculation device 10 calculates a smoothed target value such that the SOC of the battery 41 becomes the target value while stably supplying the electric power generated by the renewable energy power generation system 1 . This makes it possible to suppress deterioration of the battery 41 while suppressing fluctuations in the amount of PV power generation.
- the smoothing target value calculation device 10 will be described in more detail.
- the smoothed target value calculation device 10 includes a performance value acquisition unit 11 , a predicted value acquisition unit 12 , an SOC acquisition unit 13 , a command value generation unit 14 and a smoothed target value calculation unit 15 .
- the actual value acquiring unit 11 acquires the latest PV power actual value from the renewable energy power generation system 1 at a predetermined control cycle and stores it. For example, the actual value acquisition unit 11 acquires actual values of PV power from moment to moment.
- the predicted value obtaining unit 12 obtains the predicted value of PV power from the prediction system 3 and stores it. As the predicted value of PV power, for example, an average predicted value at each time in a predetermined time period (30 minutes) is given.
- the SOC acquisition unit 13 acquires the latest SOC of the battery 41 from the battery system 4 at predetermined control intervals. SOC acquisition section 13 outputs the acquired SOC to SOC correction section 154 .
- Command value generator 14 generates a charge/discharge command value to be output to battery system 4 .
- the command value generation unit 14 generates a charge/discharge command value by subtracting the actual value of the PV power from the smoothed target value.
- the smoothing target value calculation unit 15 calculates a smoothing target value. As described later in the third embodiment, the smoothing target value calculation unit 15 calculates a smoothing target value based on a predicted value of PV power and a smoothing target value based on an actual value of PV power. Any one of the conventional methods of calculating the value is selected to calculate the smoothed target value for each predetermined period of time. Roughly speaking, the value obtained by smoothing the predicted value of PV power for each predetermined time is the smoothed target value based on the predicted value, and the value obtained by smoothing the actual value of PV power is the smoothed target value based on the actual value. is.
- the smoothing target value calculator 15 corrects the predicted value of PV power so as to reduce this error. , calculate the smoothed target value based on the predicted value. If it is considered that the PV power can be predicted with higher accuracy by predicting the PV power in the future using the actual value of the PV power on the current day than by using the predicted value of the PV power, the smoothing target value calculation unit 15 calculates a smoothing target value (smoothing target value based on actual value) based on the actual value of PV power.
- the smoothed target value calculator 15 includes an offset corrector 151 , a sudden change corrector 152 , a predicted value smoother 153 , an SOC corrector 154 , and an actual value smoother 155 .
- the offset correction unit 151 corrects the predicted value of PV power for a short time ahead based on the difference between the actual value and the predicted value of PV power for a short time ago. This correction is called offset correction. Offset correction will be described in the first embodiment.
- the sudden change correction unit 152 corrects the predicted value of PV power based on predicted values before and after the predicted value of PV power when it is expected that the predicted value of PV power deviates greatly from the actual value. This correction is called prediction value sudden change correction.
- the prediction value sudden change correction will be described in the second embodiment.
- the predicted value smoothing unit 153 smoothes the time-series predicted value of PV power (predicted value after correction). The smoothed value becomes the smoothed target value. This smoothing processing will be described in the first embodiment.
- the SOC correction unit 154 corrects the predicted value of the PV power by adding or subtracting the power to be charged or discharged in order to bring the SOC of the battery 41 closer to the SOC target value.
- the actual value smoothing unit 155 smoothes the actual value of PV power by calculating a moving average value of the actual value of PV power.
- offset correction according to the first embodiment will be described with reference to FIG.
- the vertical axis of the graph in FIG. 2 indicates PV power, and the horizontal axis indicates time.
- the prediction system 3 predicts PV power every 30 minutes. For example, at the beginning of the day, the prediction system 3 predicts the predicted value of PV power for every 30 minutes in the same time period of the current day based on the actual value of PV power for every 30 minutes of the previous day. For example, average PV power w1 at each time from 10:30 to 11:00 on the current day is predicted based on the actual value of PV power from 10:30 to 11:00 on the previous day.
- the prediction system 3 predicts the PV power w2 from 11:00 to 11:30, the PV power w3 from 11:30 to 12:00, and the PV power w3 from 12:00 to 12:30.
- the predicted values of the PV powers w1 to w4 are set as they are as the smoothing target values. For example, if the predicted values of the PV power w1 to w4 are all 100 and the actual value of the day is 50, the battery system 4 must continue to discharge power from the battery 41 to compensate for this difference. 41 usage range (allowable SOC range).
- the offset correction unit 151 corrects the predicted value of PV power for a short time ahead based on the difference between the predicted value and the actual value of PV power.
- the prediction system 3 has already calculated the predicted values of the PV power w1 to w4, and the actual value of the PV power w1 (10:30 to 11:00) is known.
- the actual value of PV power w1 exceeds the predicted value, and the difference between the actual value and the predicted value is d1.
- the offset correction unit 151 converts the offset value (d1 ⁇ k) obtained by multiplying the difference d1 by a predetermined coefficient k to the predicted value three frames ahead, that is, the predicted value of the PV power w4 from 12:00 to 12:30. to add.
- the addition to the predicted value for the next three frames is because the next (one frame ahead) from 11:00 to 11:30 is based on the already set smoothing target value, and control is started.
- the smoothing target value at the start time of 11:30 is also the smoothing target value at the final time of the previous frame, It is because it is not appropriate to change.
- offset correction is performed at 10:00 based on the difference between 9:30 and 10:00
- the offset is corrected between 10:00 and 10:00. Offset correction is performed at 10:30 based on the difference of 30 minutes.
- the offset correction unit 151 subtracts the offset value (d1 ⁇ k) obtained by multiplying the difference d1 by a predetermined coefficient k from the predicted value of the PV power w4. Similarly, at 11:30, the offset correction unit 151 calculates the predicted value of the PV power w5 from 12:30 to 13:00 (not shown) based on the difference d2 between the actual value and the predicted value of the PV power w2. Correct the offset. As a result, it seems that there are many time periods (frames) in which the actual value exceeds or falls below the forecast value continuously, and there are many time periods (frames) in which the actual value exceeds or falls below the forecast value (even if it is not continuous).
- the predicted value can be brought closer to the actual value.
- the charge/discharge amount of the battery 41 can be suppressed.
- the predicted value of PV power predicted by the prediction system 3 based on the previous day's actual value will be higher than the actual value of the day throughout the day. may also be lower.
- the offset value to the predicted value of the PV power by the offset correction of the present embodiment, the predicted value can be brought closer to the actual measurement value, and the charge/discharge amount can be suppressed.
- the reason why the difference d1 is multiplied by the coefficient k is that, for example, the predicted value exceeds the actual value in a certain 30 minutes, the actual value exceeds the predicted value in the next 30 minutes, and the predicted value exceeds the actual value in the next 30 minutes. This is to cope with the fact that the difference between the predicted value and the actual value rather increases due to the offset correction performed when the behavior of exceeding the value occurs, resulting in an adverse effect. For example, multiplying k by a value smaller than 1 (such as 0.5) can reduce the risk of adverse effects.
- Lines L12 and L23 in FIG. 2 are the smoothing target values calculated in the past time period.
- the predicted value smoothing unit 153 calculates a point P3 at the end of the line L23 that has already been calculated, and a point P4 that is the average value of the predicted value of the PV power w3 after the offset correction and the predicted value of the PV power w4 after the offset correction. and a line L34 connecting P3 and P4 is set as the smoothing target value.
- the process of connecting the average values of the predicted values of the PV power after offset correction in adjacent time periods is the smoothing process of the predicted value.
- the average value of the PV power w2 and the offset-corrected PV power w3 in the adjacent time period is the point P3
- the offset-corrected PV power w3 and the offset-corrected PV power w4 in the adjacent time period is the point P4.
- the process of connecting the points P3 and P4 is the smoothing process.
- a smoothed line indicates the smoothed target value at that time. For comparison, a line L34' created using predicted values of PV power w3, w4 before offset correction is shown.
- FIG. 3 shows the flow of offset correction and smoothing target value calculation processing.
- the predicted value acquiring unit 12 acquires and stores predicted values of PV power every 30 minutes in advance.
- the actual value acquiring unit 11 acquires the actual value of PV power every 30 minutes on the day of control (step S1).
- the offset correction unit 151 calculates the difference d between the actual value and the predicted value of PV power for the last 30 minutes.
- the offset correction unit 151 calculates the offset value by multiplying the difference d by the coefficient k (step S2).
- the offset correction unit 151 offset-corrects the predicted value by adding or subtracting the offset value calculated in step S2 to the predicted value of the PV power in the next three time periods (frames) (step S3).
- the predicted value smoothing unit 153 executes smoothing processing (step S4).
- the predicted value smoothing unit 153 sets the smoothed target value of the PV power at the time of the boundary between time 1 and time 2 for time 1, time 2, and time 3, which are three time periods every 30 minutes.
- the average value P1 of the predicted value of PV power after offset correction at time 1 and the predicted value of PV power after offset correction at time 2 is set.
- the predicted value smoothing unit 153 adds the predicted value of PV power after offset correction at time 2 and the predicted value of PV power after offset correction at time 3 to the smoothed target value of PV power at the time on the boundary between time 2 and time 3.
- Set the average value P2 of the predicted values are set.
- the predicted value smoothing unit 153 connects the average value P1 and the average value P2 to set the smoothing target value at time 2 .
- the time-series smoothed target value created in this manner is the smoothed target value based on the predicted value of the PV power.
- the command value generator 14 calculates the difference between the momentary smoothed target value and the momentary PV power actual value, and generates a charge/discharge command value that compensates for this difference.
- the controller 42 charges and discharges the battery 41 based on the charge/discharge command value calculated by the command value generator 14 . As a result, the power indicated by the smoothed target value is supplied to the load.
- the difference d1 between the actual value and the predicted value (predicted value without offset correction) of PV power w1 was calculated. Since the offset value for the PV power w1 is calculated at the time (9:30), the difference d1' between the actual value of the PV power w1 and the predicted value after the offset correction is calculated as (d1' x k) The offset value may be calculated by
- FIG. 1 In the prediction model 31 used by the prediction system 3 to predict the PV power, the main explanatory variable is the past performance value of the prediction target time. This is because a model with higher prediction accuracy as a whole can be obtained by using the past actual values of the same time period as the main explanatory variables rather than the actual values and predicted values of the immediately preceding time. Therefore, for example, when there is a sudden change in the past performance value used as the explanatory variable, the prediction result also shows a sudden change. This state is shown in FIG.
- the dashed line graph a1 indicates the predicted value of the PV power predicted by the prediction system 3
- the solid line graph a2 indicates the smoothed target value obtained by performing offset correction and smoothing processing on the predicted value of the PV power.
- the smoothed target value shows a sharp drop and rise at time period t1.
- the solid line graph a3 shows the actual value of the PV power, showing a gentle change in the time zone t1.
- an increase in the charge/discharge amount from the battery 41 is prevented by correcting sudden changes in the predicted value by the prediction system 3 . This correction is called prediction value sudden change correction.
- FIG. 5 shows an example of predicted values of PV power every 30 minutes from 10:30 to 12:30.
- FIG. 6 shows the flow of processing for sudden change correction of predicted value.
- the predicted value wB from 11:30 to 12:00 is compared to the predicted value wA from 11:00 to 11:30 and the predicted value wC from 12:00 to 12:30. and has declined significantly.
- the sudden change correction unit 152 adjusts the predicted value when the predicted value for a certain time period deviates greatly from the predicted values for the time periods before and after that time period.
- the sudden change correction unit 152 determines whether or not the predicted value for a certain time slot greatly deviates from the predicted values for the preceding and following time slots (step S11).
- the predicted value of the PV power in a certain time period t is represented by the predicted value (t)
- the predicted values of the PV power in the time periods before and after that are represented by the predicted value (t ⁇ 1) and the predicted value (t+1), respectively
- a predetermined threshold is Let Th.
- the sudden change correction unit 152 determines whether or not the following formula (1) or formula (1') holds.
- the sudden change correction unit 152 determines whether either wB+Th ⁇ (wA+wC)/2 or wB-Th>(wA+wC)/2 holds.
- the value of the predicted value (t) after correction is not limited to formula (2), and may be a value that falls within a predetermined range based on the calculation result of formula (2).
- the sudden change correction unit 152 may calculate the predicted value (t) after correction by adding or subtracting a predetermined correction amount to the calculation result of Equation (2). In the above example, for consecutive hours every 30 minutes, if the predicted value (t) in the middle time diverges from the predicted value (t-1) or the average value of the predicted values (t+1), the predicted value Although it was decided to perform housing change correction, for example, predicted value (t - 1), predicted value (t), predicted value (t + 1), predicted value (t + 2).
- both the predicted value (t) and the predicted value (t+1) may be corrected with the values based on Equation (2).
- Equation (2) For example, in FIG. 5, the predicted value from 10:30 to 11:00 and the predicted value from 12:00 to 12:30 are both large values, and the predicted value from 11:00 to 11:30 and 11:00 If both the predicted values from 1:30 to 12:00 are extremely small values, the predicted values for two frames from 11:00 to 12:00 may be corrected based on equation (2).
- step S11 If there is no large deviation (step S11; No), that is, if neither formula (1) nor formula (1') holds, the sudden change correction unit 152 does not correct the predicted value (t) of the PV power.
- the predicted value smoothing unit 153 performs a smoothing process (step S4) to calculate a smoothed target value (whether or not the predicted value sudden change correction is executed).
- the smoothing target value calculation device 10 performs prediction value sudden change correction (steps S11 and S12) on the prediction value predicted by the prediction system 3, and performs offset correction (step S3) and smoothing on the result.
- a smoothing target value is calculated by performing a smoothing process (step S4).
- ⁇ Third embodiment> the predicted value of the PV power is corrected, and the corrected predicted value of the PV power is smoothed, thereby improving the accuracy of the smoothed target value and enabling the battery 41 to be charged. A method for suppressing discharge was described.
- calculating the smoothing target value based on the actual value of PV power in a time period slightly earlier on the same day than the predicted value of PV power predicts PV power more accurately. If possible, a method for calculating the smoothed target value by smoothing the actual value of PV power will be described.
- Figures 7A and 7B show the relationship between the amount of PV power generation and fluctuations in PV power.
- the renewable energy power generation system 1 includes photovoltaic power generation.
- Graph 7a in FIG. 7A shows time-series transitions of actual values and smoothed target values of PV power on sunny days.
- a line b1 indicates the transition of the smoothing target value
- a line c1 indicates the transition of the PV power. That is, the charge/discharge power of the battery 41 is the difference between the line b1 and the line c1.
- the graph 7b in FIG. 7B shows the time-series transition of the actual value of the PV power and the smoothed target value on a cloudy day.
- a line b2 indicates the transition of the smoothing target value
- a line c2 indicates the transition of the PV power.
- the charge/discharge power of the battery 41 is the difference between the line b2 and the line c2.
- a sunny day with respect to the graph 7a is an example of a case where the total amount of PV power generation throughout the day (the amount of power generated per day) is large.
- a cloudy day with respect to graph 7b is an example of when the total PV power generation over the course of the day is low.
- the amount of PV power generation is large, the amount of power generation varies greatly over time, and when the amount of PV power generation is small, the amount of power generation varies little over time.
- the predicted value of PV power has a certain amount of prediction error regardless of the weather, and charging/discharging is required accordingly.
- the conventional method of calculating the moving average of the actual value of PV power and using that value as the smoothing target value it is possible to On days when the amount is large, the difference between the actual PV power value and the moving average value of the actual PV power value is relatively large, so the amount of charge and discharge increases.
- cloudy days days when the amount of PV power generation is small
- the change in the amount of PV power generation over time is small. less quantity.
- this property is used to switch the calculation method of the smoothing target value based on the predicted value of the PV power amount of the next day on the previous day. Specifically, a certain threshold is set, and if the prediction result of the PV power amount for the next day (the integrated power generation amount for the day) performed on the previous day is greater than or equal to the threshold, the predicted value of PV power is used to If so, the method of calculating the moving average value of the actual value of the conventional PV power is selected.
- FIG. 8 shows calculation processing of the smoothing target value in the third embodiment.
- the prediction system 3 predicts the predicted value of the PV power for each predetermined time of the next day based on the actual value of the PV power of that day, etc. , the control target day for calculating the smoothed target value).
- the predicted value obtaining unit 12 obtains the predicted value of the PV power consumption for the next day (step S21).
- the smoothing target value calculator 15 compares the predicted value of the PV power amount for the next day with a predetermined threshold value, and determines whether the predicted value of the PV power amount is greater than the threshold value (step S22).
- step S22 If the predicted value of the PV power amount is greater than the threshold (step S22; Yes), the smoothing target value calculation unit 15 calculates the smoothing target value for each predetermined time of the next day based on the predicted value of the PV power. is determined (step S23). On the other hand, when the predicted value of the PV power amount is equal to or less than the threshold value (step S22; No), the smoothing target value calculation unit 15 calculates the smoothing target value for each predetermined time of the next day based on the actual value of the PV power. (Step S24).
- the conventional method can be used to calculate a smoothed target value with high accuracy.
- a day in which the generated power fluctuates little throughout the day is considered to be a day in which the PV power amount is small, and the smoothing target value is calculated using the conventional method on the day when the PV power amount is small. do. This makes it possible to further suppress battery deterioration.
- FIG. 9 shows an example of processing when the first to third embodiments are combined as a fourth embodiment. According to the fourth embodiment, deterioration of the battery 41 can be suppressed while smoothing the power supplied from the renewable energy power generation system 1 .
- FIG. 9 is a diagram illustrating an example of a smoothing target value calculation process according to the fourth embodiment.
- the smoothing target value calculation unit 15 performs smoothing using the process described in the third embodiment ( FIG. A conversion method is selected (step S31).
- the smoothing target value calculator 15 determines whether or not to calculate the smoothing target value (step S32).
- the process waits until the timing for calculating the smoothing target value arrives (step S32; No).
- the smoothing target value calculator 15 calculates the smoothing target value by the method selected in step S31.
- the smoothing target value calculation unit 15 smoothes the value based on the predicted value of the PV power. Calculate the conversion target value. Specifically, the predicted value obtaining unit 12 obtains the predicted value of the PV power every predetermined time (for example, every 30 minutes), and the actual value obtaining unit 11 and the SOC obtaining unit 13 obtain the latest PV power. The actual value and the latest SOC of the battery 41 are acquired. Then, the sudden change correction unit 152 performs sudden change correction of the predicted value based on the predicted value of the PV power through the process described with reference to FIG. 6 (step S33). Next, the offset correction unit 151 executes offset correction by the process described with reference to FIG. 3 at predetermined time intervals based on the predicted value and the actual value of PV power (step S34).
- the SOC correction unit 154 performs SOC correction at predetermined time intervals based on the current SOC value of the battery 41 obtained by the SOC obtaining unit 13 and a predetermined SOC target value (step S35). For example, if the current SOC of battery 41 is lower than the target value, charging is appropriate.
- the SOC correction unit 154 corrects the predicted value of the PV power after the offset correction to a smaller value so that the battery can be charged by the amount of the insufficient SOC or to prevent the SOC from further decreasing.
- the SOC correction unit 154 calculates the SOC correction power by multiplying the power corresponding to the SOC that is insufficient with respect to the target value by a predetermined coefficient, and calculates the SOC correction power after a predetermined time (for example, three frames ahead) after the offset correction. Subtract the SOC correction power from the predicted value of Conversely, if the current SOC of battery 41 is higher than the target value, discharging is appropriate. SOC correction unit 154 multiplies the power corresponding to the surplus SOC by a predetermined coefficient to obtain SOC correction power so that the surplus SOC can be discharged or the SOC is prevented from increasing further. Then, the SOC correction power is added to the predicted value of the PV power after the offset correction after a predetermined time.
- the SOC of the battery 41 can be controlled within the usable range, so deterioration of the battery 41 can be suppressed.
- the predicted value smoothing unit 153 performs the smoothing process by the process described with reference to FIG. 3 to calculate the smoothed target value (step S36 ).
- step S31 when the conventional method is selected (when the amount of power generated in one day is small), the smoothing target value calculation unit 15 calculates the smoothing target value based on the actual value of PV power.
- the actual value acquiring unit 11 and the SOC acquiring unit 13 respectively acquire the latest actual value of PV power and the latest SOC of the battery 41, for example, in a cycle of one second.
- the SOC correction unit 154 performs SOC correction on the actual value of PV power (step S37).
- the performance value smoothing unit 155 calculates a moving average value using the PV power performance value after the SOC correction, and calculates a smoothing target value (step S38).
- the smoothing target value calculator 15 repeatedly executes the processes of steps S37 and S38 at a predetermined control cycle.
- the command value generation unit 14 generates a charge/discharge command value for the battery system 4 from the difference between the smoothed target value calculated by any method and the actual value of the PV power acquired by the actual value acquisition unit 11 (step S39).
- This value indicates a charge/discharge power command value for the smoothing system 2 .
- a positive value of the charge/discharge command value indicates discharging, and a negative value indicates charging.
- the controller 42 controls charging/discharging of the battery 41 based on the charging/discharging command. Thereby, the power supplied to the load is controlled to the power indicated by the smoothed target value.
- power generated by the renewable energy power generation system 1 can be smoothed by the smoothing system 2 while suppressing deterioration of the battery 41 included in the smoothing system 2 . More specifically, the power generated by the renewable energy power generation system 1 is predicted, and the predicted result is offset-corrected based on the previous actual value, thereby suppressing the charge/discharge amount of the battery 41 and Deviation from the usage range can be suppressed.
- the SOC correction in addition to the offset correction, it is possible to more effectively prevent the battery 41 from deviating from the usable range, and contribute to suppressing deterioration of the battery. Unnecessary charge/discharge amount of the battery 41 can be avoided by the prediction value sudden change correction.
- FIG. 10 is a diagram illustrating an example of a hardware configuration of a smoothing target value calculation device according to each embodiment.
- a computer 900 includes a CPU 901 , a main memory device 902 , an auxiliary memory device 903 , an input/output interface 904 and a communication interface 905 .
- the smoothing target value calculation device 10 is implemented in a computer 900 .
- Each function described above is stored in the auxiliary storage device 903 in the form of a program.
- the CPU 901 reads out the program from the auxiliary storage device 903, develops it in the main storage device 902, and executes the above processing according to the program.
- the CPU 901 secures a storage area in the main storage device 902 according to the program.
- the CPU 901 secures a storage area for storing data being processed in the auxiliary storage device 903 according to the program.
- a program for realizing all or part of the functions of the smoothing target value calculation device 10 is recorded on a computer-readable recording medium, and the program recorded on this recording medium is read and executed by a computer system.
- the processing by each functional unit may be performed by .
- the "computer system” here includes hardware such as an OS and peripheral devices.
- the "computer system” includes the home page providing environment (or display environment) if the WWW system is used.
- the term "computer-readable recording medium” refers to portable media such as CDs, DVDs, and USBs, and storage devices such as hard disks built into computer systems.
- a smoothed target value calculation device calculates a smoothed target value, which is a target value of a total of first power generated by a renewable energy power generation system and second power charged and discharged by a battery.
- a smoothing target value calculation device 10 for calculating which includes a predicted value acquisition unit 12 that acquires the predicted value of the first electric power, and a predicted value correction unit that corrects the predicted value (offset correction unit 151, sudden change correction unit 152 , SOC correction unit 154) and a smoothing target value calculation unit (prediction value smoothing unit 153) that smoothes the corrected prediction value to calculate a smoothing target value.
- a smoothing target value calculation device is the smoothing target value calculation device of (1), wherein the predicted value correction unit (sudden change correction unit 152) is a continuous first time, With respect to the first predicted value, the second predicted value, and the third predicted value, which are the predicted values at the second time and the third time, the second predicted value, the first predicted value, and the third predicted value If the difference from the average is equal to or greater than a predetermined threshold, the second predicted value is corrected to a value based on the average value of the first predicted value and the third predicted value. As a result, it is possible to avoid excessive charging and discharging due to sudden changes in the predicted value of the PV power while the actual PV power shows a gentle change.
- a smoothing target value calculation device is the smoothing target value calculation device of (1) to (2), wherein the predicted value correction unit (offset correction unit 151) is the past adding or subtracting a value obtained by multiplying the difference between the predicted value at the fourth time and the actual value of the first electric power by a predetermined coefficient to the predicted value at the fifth time after the predetermined time from the fourth time, Correct the predicted value at the fifth hour.
- the future predicted value is corrected based on the tendency of the difference between the past predicted value and actual value of PV power. As a result, especially when the predicted value tends to exceed or fall short of the actual value, the predicted value of the PV power can be brought closer to the actual value, and the charging/discharging amount of the battery can be reduced.
- a smoothing target value calculation device is the smoothing target value calculation device of (1) to (3), wherein the smoothing target value calculation unit includes a continuous sixth time, About the sixth predicted value, the seventh predicted value, and the eighth predicted value, which are the predicted values after correction at each of the seventh time and the eighth time, the average value of the sixth predicted value and the seventh predicted value is set as the smoothed target value at the start time of the seventh time, set an average value of the seventh predicted value and the eighth predicted value as the smoothed target value at the end time of the seventh time, and set the smoothed target value at the end time of the seventh time; A value indicated by a line connecting the smoothed target value at the start time of the time and the smoothed target value at the end time of the seventh time is set as the smoothed target value at each time of the seventh time.
- the time-series smoothing target value can be calculated based on the average value of the predicted values after correction.
- the average value of the corrected predicted values even if the corrected predicted value deviates slightly from the actual PV power, the difference can be kept within an intermediate range.
- a smoothing target value calculation device is the smoothing target value calculation device according to (1) to (4), wherein a method selection unit that selects a method for calculating the smoothing target value (Smoothed target value calculation unit 15), wherein the method selection unit corrects the predicted value by the predicted value correction unit when the total of the predicted values of the first power for one day exceeds a threshold value. and smoothing the predicted value after correction using the smoothing target value calculation unit to select a method of calculating the smoothing target value, and calculating the total of the predicted value of the first power for one day is equal to or less than the threshold, a method of calculating the smoothing target value by calculating the moving average value of the actual value of the first electric power is selected.
- the actual value of PV power in the previous predetermined time is smoothed (calculating the moving average value) to calculate the smoothed target value.
- a good smoothing target value close to the actual PV power
- the predicted value of the PV power that can predict the PV power more accurately than the smoothed target value based on the actual value of the PV power is further corrected. Calculate the smoothing target value based on Thereby, the charge/discharge amount of the battery can be reduced.
- a smoothing target value calculation device calculates a smoothing target value, which is a target value of the total of the first power generated by the renewable energy power generation system and the second power charged and discharged by the battery.
- a smoothed target value calculation device for calculating the smoothed target value comprising a method selection unit that selects a method for calculating the smoothed target value, wherein the method selection unit selects the predicted value of the first power for one day If it exceeds the threshold, select the method of calculating the smoothed target value by smoothing the predicted value;
- a method of calculating the smoothed target value by calculating the moving average value of the actual values is selected.
- the actual value of PV power in the previous predetermined time is smoothed (calculating the moving average value) to calculate the smoothed target value.
- a good smoothing target value close to the actual PV power
- the PV power is predicted based on the prediction model 31 that can predict the PV power more accurately than the smoothed target value based on the actual value of the PV power.
- the smoothed target value is calculated based on the predicted value of the PV power. Thereby, the charge/discharge amount of the battery can be reduced.
- a power supply system includes a renewable energy power generation system, a battery system that charges and discharges a battery to compensate for output fluctuations of the renewable energy power generation system, and (1) to (6) and the smoothing target value calculation device according to any one of the above, wherein the battery system calculates the smoothing target value calculated by the smoothing target value calculation device and the power generated by the renewable energy power generation system.
- the battery is charged and discharged based on the difference. As a result, deterioration of the battery can be suppressed while suppressing fluctuations in the output of renewable energy power generation.
- the smoothed target value calculation method is to calculate the smoothed target value, which is the target value of the total of the first power generated by the renewable energy power generation system and the second power charged and discharged by the battery.
- a method for calculating a smoothed target value comprising: obtaining a predicted value of the first electric power; correcting the predicted value; and calculating a smoothed target value by smoothing the corrected predicted value and;
- the program according to the ninth aspect is provided in a computer for calculating a smoothed target value, which is a target value for the sum of first power generated by the renewable energy power generation system and second power charged and discharged by the battery, Acquiring a predicted value of the first power, correcting the predicted value, and smoothing the corrected predicted value to calculate a smoothed target value are executed.
- smoothing target value calculation device power supply system, smoothing target value calculation method, and program described above, deterioration of the secondary battery can be suppressed while suppressing output fluctuations in renewable energy power generation.
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Abstract
Description
本願は、2021年6月8日に、日本に出願された特願2021-095605号に基づき優先権を主張し、その内容をここに援用する。
本開示の一態様によれば、平滑化目標値算出装置は、再生可能エネルギー発電システムが発電する第1電力と電池が充放電する第2電力とを合計した電力の目標値である平滑化目標値を算出する平滑化目標値算出装置であって、前記平滑化目標値を算出する方式を選択する方式選択部、を備え、前記方式選択部は、前記第1電力の予測値の1日の合計が閾値を上回る場合、前記予測値を平滑化して、前記平滑化目標値を算出する方式を選択し、前記第1電力の前記予測値の1日の合計が閾値以下の場合、前記第1電力の実績値の移動平均値を算出して、前記平滑化目標値を算出する方式を選択する。
図1は、実施形態に係る電力供給システムの一例を示す図である。
電力供給システム100は、太陽光発電、風力発電、水力発電、地熱発電およびバイオマス発電などの再生可能エネルギー発電システム1と、平滑化システム2とを含む。平滑化システム2は、再生可能エネルギー発電システム1の出力(発電電力)の変動を平滑化する。電力供給システム100は、再生可能エネルギー発電システム1によって発電され、平滑化システム2によって平滑化された電力を、工場等の設備や商用電力系統などの負荷へ供給する。平滑化システム2は、予測システム3と、平滑化目標値算出装置10と、電池システム4とを含む。
実績値取得部11は、再生可能エネルギー発電システム1から所定の制御周期で最新のPV電力の実績値を取得し、これを記憶する。例えば、実績値取得部11は、時々刻々のPV電力の実績値を取得する。
予測値取得部12は、予測システム3からPV電力の予測値を取得し、これを記憶する。PV電力の予測値は、例えば、所定の時間(30分間)における各時刻の平均的な予測値が与えられる。
SOC取得部13は、電池システム4から所定の制御周期で最新の電池41のSOCを取得する。SOC取得部13は、取得したSOCをSOC補正部154へ出力する。
指令値生成部14は、電池システム4へ出力する充放電指令値を生成する。指令値生成部14は、平滑化目標値からPV電力の実績値を減算して、充放電指令値を生成する。
オフセット補正部151は、少し先のPV電力の予測値を、少し前のPV電力の実績値と予測値の差に基づいて補正する。この補正をオフセット補正と呼ぶ。オフセット補正については、第一実施形態で説明する。
急変補正部152は、PV電力の予測値が実績値と大きく乖離することが予想される場合に、PV電力の予測値をその前後の予測値に基づいて補正する。この補正を予測値急変補正と呼ぶ。予測値急変補正については、第二実施形態で説明する。
予測値平滑化部153は、時系列のPV電力の予測値(補正後の予測値)を平滑化する。平滑化された値が平滑化目標値となる。この平滑化処理については、第一実施形態で説明する。
SOC補正部154は、電池41のSOCをSOC目標値に近付けるために充放電する電力を加減算してPV電力の予測値を補正する。
実績値平滑化部155は、PV電力の実績値の移動平均値を算出して、PV電力の実績値を平滑化する。
(オフセット補正)
次に図2を参照して、第一実施形態に係るオフセット補正について説明する。
図2のグラフの縦軸は、PV電力を示し、横軸は時間を示す。予測システム3は、30分ごとのPV電力を予測する。例えば、予測システム3は、1日のはじめに、前日の30分ごとのPV電力の実績値に基づいて、当日の同じ時間帯における30分ごとのPV電力の予測値を予測する。例えば、前日の10時30分~11時におけるPV電力の実績値に基づいて、当日の10時30分~11時までの各時刻における平均的なPV電力w1が予測される。同様にして、予測システム3は、11時00分~11時30分までのPV電力w2、11時30分~12時00分までのPV電力w3、12時00分~12時30分までのPV電力w4を予測する。ここで、簡単な例として、PV電力w1~w4の予測値をそのまま平滑化目標値として設定する場合について考える。例えば、PV電力w1~w4の予測値が何れも100、当日の実績値が50であるとすると、電池システム4は、この差を補償する電力を電池41から放電し続けなければならず、電池41の使用範囲(SOCの許容範囲)を逸脱してしまう可能性がある。反対に、PV電力w1~w4の実績値が何れも150のように、実績値が予測値を上回り続けるような場合には、電池41は充電し続けなければならなくなり、やはり、電池41の使用範囲を大きく逸脱してしまう可能性がある。このような充放電を繰り返すと、電池41の劣化が促進されてしまう。そこで、本実施形態では、オフセット補正部151が、PV電力の予測値と実績値の差分に基づいて、少し先のPV電力の予測値を補正する。
次にPV電力の予測値に対する平滑化処理について説明する。例えば、現在が11時であるとする。図2の線L12、線L23は過去の時間帯で算出された平滑化目標値である。予測値平滑化部153は、既に算出された線L23の終了時点における点P3と、オフセット補正後のPV電力w3の予測値とオフセット補正後のPV電力w4の予測値の平均値である点P4とを結び、P3とP4とを結ぶ線L34を平滑化目標値とする。このように、所定時間(30分)ごとにPV電力の予測値が得られる場合に、隣り合う時間帯のオフセット補正後のPV電力の予測値の平均値を結ぶ処理を予測値の平滑化処理と呼ぶ。図2の例では、隣り合う時間帯のPV電力w2とオフセット補正後のPV電力w3の平均値が点P3で、隣り合う時間帯のオフセット補正後のPV電力w3とオフセット補正後のPV電力w4の平均値が点P4である。点P3と点P4を結ぶ処理が平滑化処理である。平滑化処理によってできた線は、その時間における平滑化目標値を示す。比較のため、オフセット補正前のPV電力w3、w4の予測値を用いて作成される線L34´を示す。
図3にオフセット補正および平滑化目標値算出処理の流れを示す。予測値取得部12は、事前に30分ごとのPV電力の予測値を取得して記憶している。実績値取得部11は、制御当日の30分ごとのPV電力の実績値を取得する(ステップS1)。次にオフセット補正部151が、直前の30分についてのPV電力の実績値と予測値の差dを算出する。オフセット補正部151は、差dに係数kを乗じてオフセット値を算出する(ステップS2)。次にオフセット補正部151は、3つ先の時間帯(コマ)のPV電力の予測値にステップS2で算出したオフセット値を加減算して、予測値をオフセット補正する(ステップS3)。次に予測値平滑化部153が、平滑化処理を実行する(ステップS4)。例えば、予測値平滑化部153は、連続する30分ごとの3つの時間帯である時間1、時間2、時間3について、時間1と時間2の境界の時刻におけるPV電力の平滑化目標値に、時間1のオフセット補正後のPV電力の予測値と時間2のオフセット補正後のPV電力の予測値の平均値P1を設定する。予測値平滑化部153は、時間2と時間3の境界の時刻におけるPV電力の平滑化目標値に、時間2のオフセット補正後のPV電力の予測値と時間3のオフセット補正後のPV電力の予測値の平均値P2を設定する。予測値平滑化部153は、平均値P1と平均値P2を結んで、時間2における平滑化目標値を設定する。このようにして作成された時系列の平滑化目標値がPV電力の予測値に基づく平滑化目標値である。指令値生成部14は、時々刻々の平滑化目標値と時々刻々のPV電力の実績値の差を算出して、この差を補償する充放電指令値を生成する。電池システム4では、制御装置42が、指令値生成部14によって算出された充放電指令値に基づいて、電池41の充放電を行う。これにより、負荷へは平滑化目標値が示す電力が供給される。
次に図4~図6を参照して、第二実施形態に係る予測値急変補正について説明する。予測システム3がPV電力の予測に用いる予測モデル31では、予測対象の時間の過去の実績値が主な説明変数となっている。これは、直前の時刻の実績値や予測値よりも、同じ時間帯の過去実績値を主要な説明変数とした方が、全体として予測精度の高いモデルが得られるためである。この為、例えば、説明変数に用いる過去実績値に急激な変化がある場合、予測結果においても同様に急激な変化が現れる。この様子を図4に示す。破線グラフa1は、予測システム3が予測したPV電力の予測値を示し、実線グラフa2は、PV電力の予測値に対してオフセット補正や平滑化処理を行って得られた平滑化目標値を示す。図示するように、時間帯t1にて平滑化目標値は急激な下降と上昇を示している。これに対し、実線グラフa3は、PV電力の実績値を示しており、時間帯t1においてなだらかな変化を示している。実際に図4に例示するように、実際のPV電力に急激な変化が生じることは稀であるため、予測モデルの特性に基づくPV電力の予測値の急激な変化は、電池41に対する不要な充放電の原因となる。第二実施形態では、予測システム3による予測値の急変を補正することにより、電池41からの充放電量の増加を防止する。この補正を予測値急変補正と呼ぶ。
図5の例では、11時30分~12時00分の予測値wBは、11時00分~11時30分の予測値wAや12時00分~12時30分の予測値wCに比べて、大幅に低下している。この例のように、ある時間帯の予測値が、その前後の時間帯の予測値と比べて大きく乖離する場合、急変補正部152は、その予測値をする。具体的には、まず、急変補正部152は、ある時間帯の予測値が、前後の時間帯の予測値と大きく乖離するかどうかを判定する(ステップS11)。ある時間帯tのPV電力の予測値を予測値(t)、その前後の時間帯におけるPV電力の予測値をそれぞれ予測値(t-1)、予測値(t+1)で表し、所定の閾値をThとする。急変補正部152は、以下の式(1)又は式(1´)が成立するかどうかを判定する。
予測値(t)+Th<(予測値(t-1)+予測値(t+1))÷2・・・(1)
予測値(t)-Th>(予測値(t-1)+予測値(t+1))÷2・・・(1´)
図5の例では、急変補正部152は、wB+Th<(wA+wC)÷2と、wB-Th>(wA+wC)÷2の何れかが成立するかどうかについて判定を行う。
補正後の予測値(t)=(予測値(t-1)+予測値(t+1))÷2・・・(2)
図5の例では、急変補正部152は、補正後のwB=(wA+wC)÷2によって、予測値急変補正後の予測値wBを算出する。
補正後の予測値(t)の値は、式(2)に限定されず、式(2)の計算結果を基準とし、所定の範囲内に収まるような値であってもよい。例えば、急変補正部152は、式(2)の計算結果に対して所定の補正量を加減算して補正後の予測値(t)を算出してもよい。上記の例では、30分ごとの連続する時間について、中間の時間における予測値(t)が、予測値(t-1)や予測値(t+1)の平均値と乖離している場合に予測値住変補正を行うこととしたが、例えば、予測値(t-1)、予測値(t)、予測値(t+1)、予測値(t+2)のように連続する4つの時間にうちの予測値(t)、予測値(t+1)の両方について、予測値(t-1)と予測値(t+2)との間で、共に式(1)が成立するか、又は、共に式(1´)が成立するような場合、予測値(t)、予測値(t+1)の両方を式(2)に基づく値で補正してもよい。例えば、図5において、10時30分~11時の予測値と、12時00分~12時30分の予測値とが共に大きな値で、11時~11時30分の予測値と、11時30分~12時の予測値とが共に極端に小さな値であるような場合に11時~12時の2コマ分の予測値を式(2)に基づいて補正してもよい。
第一実施形態と第二実施形態では、PV電力の予測値を補正し、補正後のPV電力の予測値を平滑化処理することにより、平滑化目標値の精度を向上し、電池41の充放電を抑制する方法について述べた。これに対し、第三実施形態では、PV電力の予測値よりも、同じ日の少し前の時間帯におけるPV電力の実績値に基づいて平滑化目標値を算出した方が精度よくPV電力を予測できる場合には、PV電力の実績値を平滑化して平滑化目標値を算出する方法について説明する。
予測値取得部12は、翌日のPV電力量の予測値を取得する(ステップS21)。次に平滑化目標値算出部15が、翌日のPV電力量の予測値と所定の閾値とを比較し、PV電力量の予測値が閾値よりも大きいかどうかを判定する(ステップS22)。PV電力量の予測値が閾値よりも大きい場合(ステップS22;Yes)、平滑化目標値算出部15は、PV電力の予測値に基づいて翌日の所定時間ごとの平滑化目標値を算出することを決定する(ステップS23)。一方、PV電力量の予測値が閾値以下の場合(ステップS22;No)、平滑化目標値算出部15は、PV電力の実績値に基づいて翌日の所定時間ごとの平滑化目標値を算出することを決定する(ステップS24)。
第一実施形態~第三実施形態を組み合わせた場合の処理例を、第四実施形態として図9に示す。第四実施形態によれば、再生可能エネルギー発電システム1から供給される電力を平滑化しつつ、電池41の劣化を抑制することができる。
図9は、第四実施形態に係る平滑化目標値の算出処理の一例を示す図である。
まず、平滑化目標値算出部15が、制御対象当日に再生可能エネルギー発電システム1が発電する発電量についての前日予測値に基づいて、第三実施形態で説明した処理(図8)により、平滑化方式を選択する(ステップS31)。次に平滑化目標値算出部15が、平滑化目標値を算出するかどうかを判定する(ステップS32)。例えば、30分ごとのPV電力の実績に基づいて、平滑化目標値を算出する場合、平滑化目標値を算出するタイミングが到来するまで待機する(ステップS32;No)。平滑化目標値を算出するタイミングが到来すると、平滑化目標値算出部15は、ステップS31で選択した方式で平滑化目標値を算出する。
以上説明したように、本実施形態によれば、再生可能エネルギー発電システム1が発電する電力を平滑化システム2によって平滑化しつつ、平滑化システム2が備える電池41の劣化を抑制することができる。より具体的には、再生可能エネルギー発電システム1が発電する電力を予測し、その予測結果を直前の実績値に基づいてオフセット補正することにより、電池41の充放電量を抑制し、電池41の使用範囲の逸脱を抑制することができる。オフセット補正に加えてSOC補正を実行することにより、電池41の使用範囲の逸脱をより効果的に防ぐことができ、電池の劣化抑制に貢献することができる。予測値急変補正により、不要な電池41の充放電量を回避することができる。再生可能エネルギー発電システム1の発電量の前日予測に基づいて、平滑化目標値の算出方式を切り替えることで、平滑化目標値と実際のPV電力の差を低減し、電池41の充放電量、劣化を抑制することができる。
コンピュータ900は、CPU901、主記憶装置902、補助記憶装置903、入出力インタフェース904、通信インタフェース905を備える。
平滑化目標値算出装置10は、コンピュータ900に実装される。そして、上述した各機能は、プログラムの形式で補助記憶装置903に記憶されている。CPU901は、プログラムを補助記憶装置903から読み出して主記憶装置902に展開し、当該プログラムに従って上記処理を実行する。CPU901は、プログラムに従って、記憶領域を主記憶装置902に確保する。CPU901は、プログラムに従って、処理中のデータを記憶する記憶領域を補助記憶装置903に確保する。
各実施形態に記載の平滑化目標値算出装置、電力供給システム、平滑化目標値算出方法及びプログラムは、例えば以下のように把握される。
予測値を補正し、補正後の予測値を平滑化して平滑化目標値を算出することにより、充放電量が少ない平滑化目標値を算出することができる。
これにより、実際のPV電力がなだらかな変化を示すのに対し、PV電力の予測値が急激な変化を示すためにおこる余分な充放電を回避することができる。
過去のPV電力の予測値と実績値の差の傾向に基づいて将来の予測値を補正する。これにより、特に予測値が実績値を上回る、下回るといった傾向がある場合に、PV電力の予測値を実際の値に近づけることができ、電池の充放電量を少なくすることができる。
これにより、補正後の予測値の平均的な値に基づいて時系列の平滑化目標値を算出することができる。補正後の予測値の平均的な値を用いることで、補正後の予測値が実際のPV電力と多少乖離する場合であっても、その差を中間的な範囲に収めることができる。
これにより、1日におけるPV電力の変動が小さいと予想できる時には、直前の所定時間におけるPV電力の実績値を平滑化(移動平均値を算出)して平滑化目標値を算出することで、精度の良い(実際のPV電力に近い)平滑化目標値を算出することができ、充放電量の低減が期待できる。反対に1日におけるPV電力の変動が大きいと予想できる時には、PV電力の実績値に基づく平滑化目標値よりも精度よくPV電力を予測することができるPV電力の予測値をさらに補正した値に基づいて平滑化目標値を算出する。これにより、電池からの充放電量を低減することができる。
これにより、1日におけるPV電力の変動が小さいと予想できる時には、直前の所定時間におけるPV電力の実績値を平滑化(移動平均値を算出)して平滑化目標値を算出することで、精度の良い(実際のPV電力に近い)平滑化目標値を算出することができ、充放電量の低減が期待できる。反対に1日におけるPV電力の変動が大きいと予想できる時には、PV電力の実績値に基づく平滑化目標値よりも精度よくPV電力を予測することができる予測モデル31に基づいて、PV電力を予測し、PV電力の予測値に基づいて平滑化目標値を算出する。これにより、電池からの充放電量を低減することができる。
これにより、再生可能エネルギー発電の出力変動を抑制しつつ、電池の劣化を抑制することができる。
1・・・再生可能エネルギー発電システム、
2・・・平滑化システム、
3・・・予測システム、
31・・・予測モデル、
4・・・電池システム、
41・・・電池、
42・・・制御装置、
10・・・平滑化目標値算出装置、
11・・・実績値取得部、
12・・・予測値取得部、
13・・・SOC取得部、
14・・・指令値生成部、
15・・・平滑化目標値算出部、
151・・・オフセット補正部、
152・・・急変補正部、
153・・・予測値平滑化部、
154・・・SOC補正部、
155・・・実績値平滑化部、
900・・・コンピュータ、
901・・・CPU、
902・・・主記憶装置、
903・・・補助記憶装置、
904・・・入出力インタフェース、
905・・・通信インタフェース
Claims (9)
- 再生可能エネルギー発電システムが発電する第1電力と電池が充放電する第2電力とを合計した電力の目標値である平滑化目標値を算出する平滑化目標値算出装置であって、
前記第1電力の予測値を取得する予測値取得部と、
前記予測値を補正する予測値補正部と、
補正後の前記予測値を平滑化して前記平滑化目標値を算出する平滑化目標値算出部と、
を備える平滑化目標値算出装置。 - 前記予測値補正部は、連続する第1時間、第2時間、第3時間の各時間における前記予測値である第1予測値、第2予測値、第3予測値について、前記第2予測値と前記第1予測値および前記第3予測値の平均との差が所定の閾値以上の場合、前記第2予測値を前記第1予測値および前記第3予測値の平均値に基づいた値に補正する、
請求項1に記載の平滑化目標値算出装置。 - 前記予測値補正部は、過去の第4時間における前記予測値と前記第1電力の実績値との差に所定の係数を乗じた値を、前記第4時間より所定時間後の第5時間における前記予測値に加減算して、前記第5時間における前記予測値を補正する、
請求項1または請求項2に記載の平滑化目標値算出装置。 - 前記平滑化目標値算出部は、連続する第6時間、第7時間、第8時間の各時間における補正後の前記予測値である第6予測値、第7予測値、第8予測値について、前記第6予測値と第7予測値の平均値を前記第7時間の開始時刻における前記平滑化目標値として設定し、前記第7予測値と第8予測値の平均値を前記第7時間の終了時刻における前記平滑化目標値として設定し、前記第7時間の開始時刻における前記平滑化目標値と前記第7時間の終了時刻における前記平滑化目標値とを結んでできる線が示す値を前記第7時間の各時刻における前記平滑化目標値として設定する、
請求項1から請求項3の何れか1項に記載の平滑化目標値算出装置。 - 前記平滑化目標値を算出する方式を選択する方式選択部、をさらに備え、
前記方式選択部は、前記第1電力の前記予測値の1日の合計が閾値を上回る場合、前記予測値補正部によって前記予測値を補正して、前記平滑化目標値算出部を用いて補正後の前記予測値を平滑化して、前記平滑化目標値を算出する方式を選択し、
前記第1電力の前記予測値の1日の合計が閾値以下の場合、前記第1電力の実績値の移動平均値を算出して、前記平滑化目標値を算出する方式を選択する、
請求項1から請求項4の何れか1項に記載の平滑化目標値算出装置。 - 再生可能エネルギー発電システムが発電する第1電力と電池が充放電する第2電力とを合計した電力の目標値である平滑化目標値を算出する平滑化目標値算出装置であって、
前記平滑化目標値を算出する方式を選択する方式選択部、を備え、
前記方式選択部は、前記第1電力の予測値の1日の合計が閾値を上回る場合、前記予測値を平滑化して、前記平滑化目標値を算出する方式を選択し、
前記第1電力の前記予測値の1日の合計が閾値以下の場合、前記第1電力の実績値の移動平均値を算出して、前記平滑化目標値を算出する方式を選択する、
平滑化目標値算出装置。 - 再生可能エネルギー発電システムと、
電池を充放電させて前記再生可能エネルギー発電システムの出力変動を補償する電池システムと、
請求項1から請求項6の何れか1項に記載の平滑化目標値算出装置と、
を備え、
前記電池システムは、前記平滑化目標値算出装置が算出した前記平滑化目標値と前記再生可能エネルギー発電システムが発電した電力との差に基づいて前記電池の充放電を行う、電力供給システム。 - 再生可能エネルギー発電システムが発電する第1電力と電池が充放電する第2電力とを合計した電力の目標値である平滑化目標値を算出する平滑化目標値算出方法であって、
前記第1電力の予測値を取得するステップと、
前記予測値を補正するステップと、
補正後の前記予測値を平滑化して前記平滑化目標値を算出するステップと、
を有する平滑化目標値算出方法。 - 再生可能エネルギー発電システムが発電する第1電力と電池が充放電する第2電力とを合計した電力の目標値である平滑化目標値を算出するコンピュータに、
前記第1電力の予測値を取得するステップと、
前記予測値を補正するステップと、
補正後の前記予測値を平滑化して前記平滑化目標値を算出するステップと、
を実行させるプログラム。
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JP2001005543A (ja) * | 1999-06-17 | 2001-01-12 | Kansai Electric Power Co Inc:The | 直流電力出力装置および太陽光発電システム |
JP2002017044A (ja) * | 2000-06-30 | 2002-01-18 | Kansai Electric Power Co Inc:The | 電力変動平滑化装置及びそれを備えた分散電源システムの制御方法 |
WO2011093362A1 (ja) * | 2010-01-27 | 2011-08-04 | 三洋電機株式会社 | 電力供給方法、コンピュータ読み取り可能な記録媒体および発電システム |
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JP2002017044A (ja) * | 2000-06-30 | 2002-01-18 | Kansai Electric Power Co Inc:The | 電力変動平滑化装置及びそれを備えた分散電源システムの制御方法 |
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