JP2013051834A - Multiple power conditioner system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multiple power conditioner system that can reduce total electricity charges by optimizing discharge control of a storage battery.SOLUTION: A storage system 30 of a multiple power conditioner system 10 has an electrical energy storage section 37a for holding past used energy of a load R and past generated energy of a photovoltaic system 20 in association with past dates; an electricity rate storage section 37b for holding electricity rates; an optimum discharge information storage section 37c for holding discharge time and maximum discharge power of a storage battery 31 calculated on the basis of the used energy, generated energy and electricity rates so as to minimize daily total electricity charges in association with past dates; and a control arithmetic section 36 for specifying the day before the preceding day that is most correlated with the preceding day by reference to the electrical energy storage section 37a, and controlling a drive section 35 on the basis of the discharge time and maximum discharge power of the day after the specified day held in the optimum discharge information storage section 37c.

Description

  The present invention relates to a multi-power conditioner system including a photovoltaic power generation system and a power storage system.

  In recent years, from the viewpoint of global warming prevention, new energy sources that do not rely on fossil fuels, in particular, power generation systems that use natural energy sources have been actively studied. Among them, the photovoltaic power generation system is expected to become more popular in the future because the power generation cost is approaching the same level as the power generation cost of the existing power generation system.

  Further, in recent years, power storage systems that aim at leveling of power demand and reducing electric charges by discharging storage batteries charged with inexpensive late-night power during the daytime when power demand is large are becoming widespread. For example, Patent Document 1 discloses a power storage system in which a plurality of discharge patterns having different time zones for discharging a storage battery are stored in advance. According to this power storage system, when a user selects one discharge pattern, the timing at which the storage battery is discharged is optimized, and inexpensive midnight power can be effectively utilized.

JP 2001-8385 A

  However, since the power storage system leaves the selection of the discharge pattern to the user, (1) the burden on the user is large, (2) the optimum discharge pattern is not necessarily selected, and midnight power is effectively utilized. There was a problem that it was not possible.

  In addition, in a multi-power conditioner system that uses the above power storage system and a solar power generation system in combination, it is necessary to analyze the power generation amount of the solar power generation system and the power consumption of the load in order to select an optimal discharge pattern. However, since these fluctuate day by day, there was a problem that (3) selection of an optimal discharge pattern was practically impossible.

  This invention is made | formed in view of the said situation, The place made into the subject provides the multi-power conditioner system which can reduce a total electricity bill by optimizing the discharge control of a storage battery. There is.

  In order to solve the above-described problems, a multi-power conditioner system according to the present invention includes a multi-power conditioner including a photovoltaic power generation system and a power storage system connected to power lines respectively branched from a main power line that connects a system and a load. The solar power generation system includes a solar battery and a solar power conditioner that supplies power from the solar battery to the main power line, and the power storage system supplies power to the storage battery and the storage battery. A storage power conditioner that supplies and receives power to the load, and the storage power conditioner detects detection data related to the amount of power used by the load and detection data related to the amount of power generated by the solar cell. Electricity storage unit that stores data related to electricity and electricity charges for storing data related to electricity charges per unit time In order to minimize the total electricity bill per day, the storage battery discharge time and the discharge based on the detection data relating to the amount of power used, the detection data relating to the amount of generated power and the data relating to the electricity bill per unit time A control calculation unit that calculates a discharge pattern related to the maximum discharge power at the time, and an optimal discharge information storage unit that stores the discharge pattern calculated by the control calculation unit in association with the detection date, and the control calculation unit stores the electric energy The storage battery is identified based on the discharge pattern of the specific day or the next day held in the optimal discharge information storage unit by specifying the day before yesterday having the highest correlation with the detection data related to the amount of power used yesterday with reference to the unit. It controls to supply electric power to the load from.

  In this configuration, data related to past power consumption and generated power is associated with a past date (detection date) and held in the power storage unit, and the total daily electricity bill is minimized. Data relating to the calculated discharge time and maximum discharge power of the storage battery is stored in the optimum discharge information storage unit in association with the past date. Further, in this configuration, the control calculation unit specifies the day before the day before yesterday having the highest correlation with yesterday, and controls the discharge of the storage battery based on the data relating to the discharge time and the maximum discharge power on the specific day or the day after that day. . Therefore, according to this configuration, since the discharge time and the maximum discharge power suitable for minimizing the total electricity bill are automatically determined based on the past results, the storage battery can be operated without imposing a burden on the user. The discharge control can always be optimized.

  As a specific configuration of the multi-power conditioner system, a storage power conditioner includes a bidirectional DC / DC converter in which one input / output terminal is connected to a storage battery and the other input / output of the bidirectional DC / DC converter. A bidirectional DC / AC inverter having one input / output terminal connected to the end and the other input / output terminal connected to the main power line, and a drive unit for driving the bidirectional DC / DC converter and the bidirectional DC / AC inverter The control calculation unit controls the drive unit based on the discharge pattern on the specific date or the next day held in the optimum discharge information storage unit, so that when the discharge time is reached, the drive unit is bidirectional DC. A configuration in which the storage battery is discharged with the maximum discharge power by driving the DC / DC converter and the bidirectional DC / AC inverter is conceivable.

  The control calculation unit of the multi-power conditioner system can identify the day having the highest correlation with yesterday, for example, based on whether or not the time change of the power consumption is approximate.

  In addition, the multi-power conditioner system includes a photovoltaic power generation current detection unit interposed in a power line branched from the trunk power line and connected to the photovoltaic power system, and on the trunk power line, In the case of further comprising a load use current detection unit interposed on the load side from the branch point with the connected power line, the control calculation unit detects the photovoltaic power generation current detected by the photovoltaic power generation current detection unit Power generation power and power consumption are calculated at predetermined intervals based on the load current detected by the load current detection unit and the system voltage, and data about the calculated power generation and power consumption is What is necessary is just to store in a quantity memory | storage part.

  ADVANTAGE OF THE INVENTION According to this invention, the multi-power conditioner system which can reduce a total electricity bill can be provided by optimizing the discharge control of a storage battery.

1 is a block diagram of a multi-power conditioner system according to the present invention. FIG. It is a flowchart of the discharge control in the multi-power conditioner system which concerns on this invention.

  Hereinafter, a preferred embodiment of a multi-power conditioner system according to the present invention will be described with reference to the accompanying drawings.

[Configuration of multi-power conditioner system]
FIG. 1 shows a block diagram of a multi-power conditioner system according to the present invention. As shown in the figure, the multi-power conditioner system 10 is mainly composed of a photovoltaic power generation system 20 and a power storage system 30. The solar power generation system 20 includes a solar battery 21 and a solar power conditioner 22, and the power storage system 30 includes a storage battery 31 and a power storage power conditioner 32.

  The solar power generation system 20 and the power storage system 30 are connected to a power line L2 and a power line L3 branched from the main power line L1 that connects the system G and the load R, respectively. When the grid G side is the upstream and the load R side is the downstream, the solar power generation system 20 is connected to the main power line L1 upstream of the power storage system 30.

  The main power line L1 is provided with a system current detection unit CT1 and a load use current detection unit CT3 each including a current transformer. The system current detection unit CT1 and the load use current detection unit CT3 are for detecting the amount of current flowing through the main power line L1. An output signal of the grid current detection unit CT1, that is, a signal related to the current amount upstream from the connection point between the main power line L1 and the power line L2, is input to the solar power conditioner 22. On the other hand, the output signal of the load use current detector CT3, that is, a signal related to the current amount upstream from the connection point between the main power line L1 and the power line L3 (downstream from the connection point between the main power line L1 and the power line L2) is stored in the storage power conditioner. 32.

  A photovoltaic power generation current detector CT2 including a current transformer is provided on the power line L2 that connects the photovoltaic power generation system 20 and the main power line L1. The photovoltaic power generation current detector CT2 is for detecting the amount of current flowing through the power line L2, that is, the amount of current flowing from the photovoltaic power generation system 20 toward the main power line L1. The output signal of the photovoltaic power generation current detection unit CT2 is input to the power storage power conditioner 32.

  As indicated by arrows in FIG. 1, the solar power generation system 20 supplies the power generated by the solar cell 21 to the main power line L1 via the power line L2. The electric power supplied to the main power line L1 is consumed by the load R or is reversely flowed (sold) into the grid G.

  The power storage system 30 charges the storage battery 31 using relatively inexpensive late-night power supplied from the system G and supplies the stored power of the storage battery 31 to the main power line L1 via the power line L3. The power supplied from the power storage system 30 to the main power line L1 is supplied only to the load R and is not sold. This is because the power storage system 30 performs so-called reverse power flow prevention control. In reverse power flow prevention control, the product of the output voltage (= system voltage) of the power storage system 30 and the current flowing from the upstream to the downstream detected by the load use current detection unit CT3, that is, the system active power is negative. Therefore, the output voltage of the power storage system 30 is controlled so that it does not occur.

  The storage power conditioner 32 of the storage system 30 includes a bidirectional DC / DC converter 33 having one input / output terminal connected to the storage battery 31 and one input / output terminal to the other input / output terminal of the bidirectional DC / DC converter 33. And a bidirectional DC / AC inverter 34 having an output terminal connected thereto. The other input / output terminal of the bidirectional DC / AC inverter 34 is connected to the main power line L1 via the power line L3.

  When the storage battery 31 is discharged, the bidirectional DC / DC converter 33 converts the storage power of the storage battery 31 input from one input / output terminal into DC power having a predetermined voltage value, and converts the DC power to the other input. Output from the output terminal. The bidirectional DC / AC inverter 34 converts the DC power input from one input / output terminal into AC power synchronized with the phase of the system G, and outputs the AC power from the other input / output terminal.

  When the storage battery 31 is charged, the bidirectional DC / AC inverter 34 converts AC power of the system G input from the other input / output terminal into DC power having a predetermined voltage value, and the DC power is input to one input. Output from the output terminal. The bidirectional DC / DC converter 33 converts DC power input from the other input / output terminal into DC power having an appropriate voltage value, and outputs the DC power from one input / output terminal.

  As shown in FIG. 1, the power storage power conditioner 32 further includes a drive unit 35, a control calculation unit 36, and a storage unit 37. The drive unit 35 drives (opens and closes) a power semiconductor switching element such as an IGBT included in the bidirectional DC / DC converter 33 and the bidirectional DC / AC inverter 34 so as to perform the above-described operation. The storage unit 37 includes an electric energy storage unit 37a, an electricity rate storage unit 37b, and an optimum discharge information storage unit 37c, and data necessary for discharge control of the storage battery 31 is stored in each of the storage units 37a to 37c.

  The control calculation unit 36 includes data on the amount of generated power calculated from the photovoltaic power generation current and the system voltage detected by the photovoltaic power generation current detection unit CT2, and the load usage current and the system voltage detected by the load usage current detection unit CT3. In addition to storing data related to the power consumption calculated from the power amount storage unit 37a every predetermined time (for example, every hour), the drive unit 35 is controlled based on various data held in the storage unit 37, The switching elements of the bidirectional DC / DC converter 33 and the bidirectional DC / AC inverter 34 are driven.

[Discharge control in multi-power conditioner system]
Next, discharge control in the multi-power conditioner system 10 according to the present invention will be described with reference to FIG. As shown in the figure, the discharge control in the multi-power conditioner system 10 includes a flow F1 including steps S1 to S3 and a flow F2 including steps S4 to S7. As shown in FIG. 2A, the flow F1 is repeatedly executed at a rate of once / hour. Further, as shown in FIG. 2B, the flow F2 is repeatedly executed at a pace of once / day.

ステップＳ１およびステップＳ２は、実行順序を逆にしてもよい。すなわち、使用電力量を先に求め、その後で発電電力量を求めてもよい。 In step S1 of flow F1, the control calculation unit 36 obtains the amount of generated power based on the photovoltaic power generation current and the system voltage detected by the photovoltaic power generation current detection unit CT2. In step S2, the control calculation unit 36 obtains the amount of power used based on the load usage current and the system voltage detected by the load usage current detection unit CT3. The amount of generated power and the amount of power used can be obtained from the following equations, respectively.

Steps S1 and S2 may be executed in reverse order. That is, the amount of power used may be determined first, and then the amount of generated power may be determined.

In step S3, the control calculation unit 36 stores the data related to the generated power amount and the used power amount obtained in step S1 and step S2 in the power amount storage unit 37a. Data relating to the amount of generated power and the amount of power used is stored in association with the date of the day. Further, as described above, the flow F1 is repeatedly executed once per hour. Therefore, data as shown in Table 1 and Table 2 is accumulated in the electric energy storage unit 37a. The amount of data held in the electric energy storage unit 37a can be arbitrarily set, but in order to optimize the discharge control, it is preferable to hold data for the past several weeks to one year. Immediately after the start of the use of the multi-power conditioner system 10 according to the present invention, there is a possibility that accumulated data does not exist or is insufficient, which may hinder optimization of discharge control. For this reason, in the electric energy storage unit 37a, default data based on the monthly electricity bill of the house where the multi-power conditioner system 10 is installed, the power generation capacity of the solar cell 21, and the like are stored in advance as initial values. It is preferable that the user can arbitrarily select whether to perform discharge control based on accumulated data or to perform discharge control based on default data.

  Next, the flow F2 will be described. The flow F2 includes steps S4 to S7, of which steps S4 to S6 are executed at the beginning of the day (around 0:00 to 6:00), and step S7 is executed at the end of the day (after 23:00). Is done. The reason why Steps S4 to S6 are executed at the beginning of the day is because it is necessary to determine the discharge time of the day before the power consumption of the load R increases. Further, the reason why Step S7 is executed at the end of the day is because it is necessary to refer to the generated power amount data and the used power amount data at 23:00 on that day.

  In step S4 of the flow F2, the control calculation unit 36 refers to the power amount storage unit 37a, and identifies the day before yesterday (hereinafter referred to as “correlation date”) having the highest correlation with yesterday. To identify the correlation date, for example, using the autocorrelation function, obtain the correlation value between the time change of the power consumption of yesterday and the time change of the power consumption of each day before the day before yesterday, and correlate the day with the highest correlation value This is done by setting the date. Usually, the correlation values tend to increase between days with similar time changes.

  In step S5, the control calculation unit 36 reads the discharge time data and maximum discharge power data on the next day of the correlation date from the optimum discharge information storage unit 37c. As will be described in detail later, the discharge time data and the maximum discharge power data are those stored by the control calculation unit 36 in the optimum discharge information storage unit 37c in step S7 before yesterday.

  In step S <b> 6, the control calculation unit 36 controls the drive unit 35 based on the read discharge time data and maximum discharge power data. Thus, when the discharge time comes, the drive unit 35 drives the bidirectional DC / DC converter 33 and the bidirectional DC / AC inverter 34, and the storage battery 31 is discharged with the maximum discharge power.

  In step S7, based on the generated power amount data and the used power amount data of the day held in the power amount storage unit 37a, and the electricity rate data held in the electricity rate storage unit 37b, the control calculation unit 36 The discharge time and maximum discharge power of the day are obtained and stored in the optimum discharge information storage unit 37c as discharge time data and maximum discharge power data.

In the electricity bill storage unit 37b, data on the electricity fee to be paid when 1 kWh of electric power is purchased from the electric power company through the system G, and data on the electricity fee to be paid when the electric power company sells 1 kWh of electric power. Are stored in advance. These electricity rate data are updated to the latest one manually or automatically each time the rate is revised. Table 3 shows an example of electricity rate data.

  As shown in the table above, the electricity price at the time of power purchase varies according to the time zone in order to promote the leveling of power demand. For this reason, even when purchasing 10 kWh of power from an electric power company, it is necessary to purchase between 7: 00 and 9: 59 and between 10: 00 and 16: 59. There is a difference in the amount to be paid to the company. Moreover, even if it is a case where the electric power purchased from an electric power company is reduced by discharging the storage electric power of the storage battery 31 by 10 kWh, and it reduces a total electricity bill, if it discharges between 7: 00-9: 59, 10 : A difference occurs in the amount that can be reduced by discharging between 00 and 16:59. Therefore, in order to minimize the total electricity bill, it is extremely important how much power is discharged in which time zone.

  Various methods for calculating the discharge time and the maximum discharge power for minimizing the total electricity bill are conceivable. In this embodiment, the discharge time and the maximum discharge power are calculated by the following method as an example.

That is, after calculating the daily power purchase amount (payment to the power company) and power sale amount (payment from the power company) by the following formula,

Electricity purchase amount = Σ {BP (t) × C (t)}
Amount of electricity sold = Σ {SP (t) × D (t)}

The total electricity price for one day is obtained by calculating the difference between the amount purchased and the amount sold. However, BP (t), SP (t), C (t), and D (t) are the amount of power purchased at the time of t, the amount of power sold, the electricity charge at the time of power purchase, the electricity charge at the time of power sale, t = 0 to 23.

  The above calculation is repeated while changing the discharge time and the maximum discharge power, and the discharge time and the maximum discharge power at which the daily total electricity price is the lowest are used as the discharge time data and the discharge maximum power data. 37c. Note that the set of the discharge time and the maximum discharge power is not limited to one, and there may be a plurality of sets per day.

上表から明らかなように、○月１日は、１３：００〜１４：５９の間に放電最大電力１０ｋＷｈで蓄電池３１の放電を行うのが電気料金の観点から望ましいのに対し、○月２日は、１２：００〜１２：５９の間に放電最大電力１０ｋＷｈで１回目の放電を行った後、さらに１５：００〜１６：５９の間に放電最大電力５ｋＷｈで２回目の放電を行うことが望ましい。 Table 4 shows an example of discharge time data and discharge maximum power data.

As can be seen from the above table, on January 1, it is desirable to discharge the storage battery 31 with a maximum discharge power of 10 kWh between 13: 00 and 14:59 from the viewpoint of electricity charges, On the day, after the first discharge with a maximum discharge power of 10 kWh between 12: 00 and 12:59, the second discharge with a discharge maximum power of 5 kWh is performed between 15: 00 and 16:59. Is desirable.

  In step S5 after the next day, the discharge time data and the maximum discharge power data of the next day of the correlation date are read from the optimum discharge information storage unit 37c, and the discharge control of the storage battery 31 is controlled according to the read discharge time data and the maximum discharge power data. Done. For example, if the correlation date is 1 month, the discharge time data and the maximum discharge power data (12: 00 to 12: 59/10 kWh, 15: 00 to 16 on the next day of the month 2) in step S5. : 59/5 kWh) is read out. In step S6, the storage battery 31 is discharged in two steps of 12: 0 to 12:59 and 15: 0 to 16:59.

The preferred embodiment of the multi-power conditioner system according to the present invention has been described above, but the present invention is not limited to the above configuration.
For example, in the above embodiment, the flow F1 is repeatedly executed at a pace of 1 time / hour, but may be a pace of 2 times / 1 hour or may be a pace of 0.5 times / 1 hour. However, in order to correctly specify the correlation date and accurately obtain the discharge time and the maximum discharge power, it is desirable that the number of executions per hour be one or more.
Tables 1 to 4 are all examples, and the format of data held in the storage unit 37 can be any format.

  In addition, if there are multiple days with a high correlation value between the time change of the power consumption of yesterday and the time change of the power consumption of each day before the day before yesterday, in addition to the correlation value, the day of the week, weekday or holiday The correlation date may be specified in consideration. For example, if there are multiple days with the same correlation value, it is then determined whether the day is the same day as yesterday's day of the week. The correlation date may be specified. Furthermore, for example, when yesterday is a holiday, if there is a day corresponding to a holiday among a plurality of correlation values having the same correlation value, the day may be specified as the correlation date.

  In the above embodiment, the control calculation unit 36 reads the discharge time data and the maximum discharge power data on the next day of the correlation date from the optimum discharge information storage unit 37c, and controls based on the read discharge time data and the maximum discharge power data. Although the calculation unit 36 controls the drive unit 35, the present invention is not limited to this. The discharge time data and the maximum discharge power data of the correlation date itself are read from the optimum discharge information storage unit 37c, and the read discharge time data and The control calculation unit 36 may control the drive unit 35 based on the maximum discharge power data. In executing the discharge control of the storage battery 31 on the current day from the day having the highest correlation with the yesterday's data (correlation date), it can be said that it is preferable to read the data on the next day of the correlation date. Also has the effect of the present invention. That is, even when the drive unit 35 is controlled based on the discharge date data and the maximum discharge power data on the correlation day, the discharge time and the maximum discharge power suitable for minimizing the total electricity bill are automatically determined. Can do.

DESCRIPTION OF SYMBOLS 10 Multi power conditioner system 20 Solar power generation system 21 Solar cell 22 Solar power conditioner 30 Electric storage system 31 Storage battery 32 Electric storage power conditioner 33 Bidirectional DC / DC converter 34 Bidirectional DC / AC inverter 35 Drive part 36 Control calculation Unit 37 Storage unit 37a Electric energy storage unit 37b Electricity rate storage unit 37c Optimal discharge information storage unit G System L1 Core power line CT1 System current detection unit CT2 Photovoltaic power generation current detection unit CT3 Load usage current detection unit

Claims (4)

A multi-power conditioner system including a photovoltaic power generation system and a power storage system connected to power lines branched from a main power line connecting a system and a load,
The solar power generation system includes a solar battery and a solar power conditioner that supplies power from the solar battery to the main power line.
The power storage system includes a storage battery, and a storage power conditioner that supplies and receives power to the storage battery and supplies power to the load.
The power storage power conditioner is:
A power storage unit that stores detection data related to the power consumption of the load and detection data related to the generated power of the solar cell in association with the detection date;
An electricity bill storage unit for storing data relating to electricity bills per unit time;
In order to minimize the total electricity charge per day, the discharge time of the storage battery and the discharge are based on the detection data related to the amount of power used, the detection data related to the amount of generated power and the data related to the electricity charge per unit time. A control calculation unit for calculating a discharge pattern related to the maximum discharge power at the time,
An optimal discharge information storage unit that stores the discharge pattern calculated by the control calculation unit in association with the detection date;
The control arithmetic unit refers to the electric energy storage unit, identifies the day before yesterday having the highest correlation with the detection data related to the electric energy used yesterday, and is held in the optimum discharge information storage unit A multi-power conditioner system that controls to supply power from the storage battery to the load based on the discharge pattern on a specific day or the next day. The power storage power conditioner is:
A bidirectional DC / DC converter having one input / output terminal connected to the storage battery;
A bidirectional DC / AC inverter having one input / output terminal connected to the other input / output terminal of the bidirectional DC / DC converter and the other input / output terminal connected to the main power line;
A drive unit for driving the bidirectional DC / DC converter and the bidirectional DC / AC inverter;
By controlling the drive unit based on the discharge pattern of the specific date or the next day held in the optimal discharge information storage unit, the control calculation unit,
The said drive part drives the said bidirectional | two-way DC / DC converter and the said bidirectional | two-way DC / AC inverter when the said discharge time comes, The said storage battery is discharged with the said discharge maximum electric power. Multi-power conditioner system.   3. The multi-power conditioner system according to claim 1, wherein the control calculation unit specifies a day having the highest correlation with yesterday depending on whether or not the time change of the power consumption is approximate. . A photovoltaic power generation current detector branching from the main power line and intervening in a power line connected to the photovoltaic power generation system;
On the main power line, further comprising a load use current detection unit interposed on the load side from a branch point with the power line connected to the solar power generation system,
The control calculation unit is configured to generate the generated power based on the photovoltaic power generation current detected by the photovoltaic power generation current detection unit, the load usage current detected by the load usage current detection unit, and the system voltage. The multi-use according to any one of claims 1 to 3, wherein a power consumption is calculated every predetermined time, and the calculated power generation amount and data relating to the power consumption are stored in the power storage unit. Power conditioner system.

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