JP2023019166A - Charge/discharge control device and charge/discharge control program - Google Patents

Abstract

To discharge or charge power stored in a power storage part for load fluctuations, especially increases or decreases in the load that cannot be fully handled by a private power generation device to control an appropriate amount of discharge or charge.SOLUTION: When the load increases rapidly, discharging of a power storage part 12 is started. The discharge is gradually decreased as the amount of power generated by a power generating unit 10 increases. A zero-crossing point frequency of a frequency-charge/discharge control characteristic of the power storage unit 12 is shifted (in discharge, shift it to the left in Fig. 4) to follow a target frequency changing by droop control to forcibly terminate the discharge. Thereby, the amount of power generation returns to that before the rapid load increase caused by a droop control.SELECTED DRAWING: Figure 4

Description

The present invention relates to a charge/discharge control device and a charge/discharge control program for a power storage unit that assists in-house power generation.

Patent Document 1 describes a power generation unit that is normally connected to a commercial system and is driven by a prime mover independently from the commercial system when the commercial system fails, etc.; In a method for operating a private power generation facility equipped with a charge/discharge control device for controlling charge/discharge of a storage unit, when an increase in load is detected, the power storage unit outputs (discharges) the increased amount of load to the power storage unit. After that, the output of the power storage unit is gradually reduced at a speed below the allowable fluctuation load of the power generation unit, and when the output of the power storage unit becomes 0, the load sharing process is terminated. A method of operating a private power generation facility is described which is characterized by improving the load-throwing rate of the power generation facility. It should be noted that the same effect can be obtained even when the load is reduced.

Japanese Patent Application Laid-Open No. 2007-6595

However, in the conventional operating method, when an increase in load is detected, all the power temporarily stored in the power storage unit for the increase is discharged. In other words, the power storage unit needs to have a capacity capable of charging an amount corresponding to the load increase in advance.

Further, when the private power generator has a droop control function, the frequency during operation may deviate from the frequency set as the reference depending on the output of the private power generator. Due to this frequency deviation, the power generated by the in-house power generator is stabilized with less power than the required amount of power (occurrence of an offset corresponding to the frequency deviation). This offset will continue to discharge from the power storage unit.

The present invention discharges or charges the electric power stored in the electric power storage unit in response to load fluctuations, particularly an increase or decrease in the load that cannot be handled by the in-house power generator, and controls the amount of discharge/charge to be appropriate. An object of the present invention is to obtain a charge/discharge control device and a charge/discharge control program that can

The charge/discharge control device according to the present invention generates power by driving the prime mover, and when synthesizing the power generated by itself and the power generated by others, changes the target frequency according to the load of the power generation output of itself. a power generator having a droop control function that adjusts the load factor by increasing the load factor; In the device, a frequency at which the power generated by the power generation unit and the power required by the load match is set as a zero-crossing point frequency at which charging and discharging are not performed, and the frequency is lower than the zero-crossing point frequency. A charge/discharge control unit that discharges when power generation is insufficient and charges when power generation is excessive when the frequency is higher than the zero-crossing point frequency, and the charge/discharge control unit controls that the amount of power required by the load exceeds a standard. When the amount of power generated by the power generation unit changes to increase or decrease, and an excess or deficiency occurs in the amount of power generated, the power storage unit is controlled to discharge when power generation by the power generation unit is insufficient and to charge when power generation is excessive. In addition, when the target frequency of the droop control function changes during discharging or charging, the zero-crossing point frequency is shifted in accordance with the change in the target frequency to prevent discharging or charging from the power storage unit. It is characterized by adjusting the end time.

According to the present invention, the charge/discharge control device sets the frequency at which the power generated by the power generation unit and the power required by the load match as the zero-cross point frequency at which charging and discharging are not performed, and the zero-cross point frequency When the frequency is too low, the battery is discharged, and when the frequency is higher than the zero-cross point frequency, the battery is charged.

Here, the charge/discharge control device controls the power storage unit when the amount of power required by the load changes to increase or decrease beyond the standard and the amount of power generated by the power generation unit becomes excessive or insufficient. In addition, when the power generation unit is underpowered, it is discharged, and when it is overpowered, it is charged. When the target frequency of the droop control function changes during discharging or charging, the zero cross point frequency is adjusted according to the change in the target frequency. to adjust the end timing of discharging or charging from the power storage unit.

As a result, the electric power accumulated in the electric power storage unit is discharged or charged in response to load fluctuations, especially the increase or decrease of the load that cannot be handled by the in-house power generator, and is controlled to an appropriate discharge amount/charge amount. be able to.

In the present invention, under the condition that the charge/discharge control unit generates self-sustaining power, the power required by the load increases more than a predetermined amount, and when the target frequency of the droop control function changes to become lower, the zero-crossing When the point frequency is shifted to the lower frequency side, the electric power required by the load decreases more than a predetermined amount, and the target frequency of the droop control function changes to become higher, the zero-crossing point frequency is shifted to the lower frequency side. It is characterized by shifting to the high side.

For example, when a power outage occurs, the power demanded by the load surges after the power goes down. At K, the target frequency for droop control becomes low due to a sudden change in the power generation of the power generation unit depending on the state of self-sustaining power generation. Therefore, when the target frequency of the droop control function changes to become lower, the zero-cross point frequency is shifted to the lower frequency side. The same is true for a sudden decrease in load. When the power required by the load suddenly decreases more than a predetermined amount and the target frequency of the droop control function changes to become higher, the zero-crossing point frequency is shifted to a higher frequency side. Just do it.

In the present invention, the charge/discharge control unit includes a table for controlling charging and discharging in the power storage unit according to the frequency corresponding to the power generated by the power generation unit, and the zero cross point frequency of the table is updated based on the default target frequency of the droop control function.

Since the zero-cross point frequency can be appropriately updated according to the target frequency in the droop control function, it is possible to stabilize the power generation of the power generation section during rapid load fluctuations.

The present invention is characterized in that the discharge or charge by the power storage unit by the charge/discharge control unit is gradually decreased in proportion to the elapsed time from the point of time when the discharge or charge by the power storage unit is terminated, and the end state is reached.

For example, when the load increases, the load is gradually decreased at a constant rate of change, so that the power storage unit does not repeat discharge and discharge stop, and the power generation amount of the power generation unit gradually increases and gradually converges (power generation The power generation amount of the part = the required load). It can be handled with the minimum amount of discharge required.

The present invention is characterized in that discharging is stopped immediately at the time when the charge/discharge control unit terminates discharging or charging by the power storage unit.

For example, when the load is increased, if the discharge is terminated immediately, the difference between the power generation amount of the power generation unit and the load remains, and the discharge and discharge stop of the power storage unit are repeated several times, but the difference is Since it gradually converges (amount of power generated by the power generation unit=required load), the charge/discharge 0 (charge/discharge end) state can finally be achieved. At least, the amount of discharge can be reduced more than when discharging is continued.

A charge/discharge control program according to the present invention operates a computer as the charge/discharge control unit.

As described above, according to the present invention, the electric power stored in the electric power storage unit is discharged or charged in response to load fluctuations, particularly an increase or decrease in the load that cannot be handled by the in-house power generator, and an appropriate discharge amount is obtained.・The effect of being able to control the amount of charge can be obtained.

FIG. 3 is a functional block diagram for power generation/discharge control during grid isolation in the power generation system according to the present embodiment; FIG. 4 is a droop control function characteristic diagram applied to the power generation system according to the present embodiment; 3A is a flowchart showing a power storage unit charging/discharging control routine according to the present embodiment, and FIG. 3B is a flowchart showing a power generation/discharging control routine during grid isolation in the power generation system according to the present embodiment. 4 is a frequency-charging/discharging characteristic diagram in the power storage unit according to the present embodiment. FIG. FIG. 4 is a frequency-change rate characteristic diagram during power generation/discharge control during grid isolation in the power generation system according to the present embodiment. FIG. 10 is a diagram of power and frequency transition characteristics during grid isolation according to a comparative example;

FIG. 1 is an overall configuration diagram of a power generation system provided with a power generation unit 10 and a power storage section 12 according to this embodiment.

The power generation unit 10 includes a prime mover 14 and a power generation section 16 that generates power by driving the prime mover 14 .

A gas engine, a gas turbine engine, a diesel engine, or the like can be used as the prime mover 14, and can be applied to a cogeneration system.

Also, the power storage unit 12 has a function of storing power, and may be any facility as long as it has a quick response characteristic. An ion capacitor, a lithium ion secondary battery, or the like can be used. Here, the quick response characteristic of the power storage unit 12 means, for example, the characteristic that the prime mover 14 can be charged and discharged in a shorter time than the output response time.

Functions for controlling the prime mover 14 and the power generation section 16 will be mainly described below, but each block is not limited to the configuration, but is an example for describing the function.

As shown in FIG. 1 , a droop control section 18 is connected to the power generation section 16 and the prime mover 14 . A droop control unit 18 controls driving of the prime mover 14 (droop control).

More specifically, the droop control unit 18 acquires the output information of the power generation by the power generation unit 16, sets the target frequency based on a predetermined frequency-output characteristic diagram (see FIG. 2), and adjusts the target frequency to the set target frequency. Based on this, the driving of the prime mover 14 is controlled.

Droop control is a control for adjusting the target frequency according to the output and matching the frequency of another power generation system (including commercial power supply) to generate power. Backflow of electric power can be prevented.

The power generation unit 16 discharges the generated power through the output unit 20 and supplies the power to the multiple loads 22 .

Here, the power generation unit 10 includes a frequency detection section 24 , detects the frequency based on output information from the power generation section 16 acquired by the droop control section 18 , and sends the detected frequency to the control section 26 .

The control unit 26 controls the power generation amount of the power generation unit 16 based on the frequency (which varies depending on the load) detected by the frequency detection unit 24 .

On the other hand, the power storage unit 12 is charged with power from a charging power source (including the power generation system in FIG. 1, other power generation systems, commercial power, solar power generation, etc.) and stores power, and is a charge/discharge control device. 28 controls to supply power to multiple loads 22 .

By being connected to the control unit 26 of the power generation unit 10, the charge/discharge control device 28 acquires information related to power generation by the power generation unit, and also receives independent operation instruction information and load information (here, the premises frequency), It controls the power generation of the power generation unit 16 and the discharge of the power of the power storage unit 12 when a predetermined condition is satisfied. Predetermined conditions will be described later.

(Sudden load change)

Here, if the load applied to the prime mover 14 suddenly changes (for example, increases), the frequency of the generator 16 may exceed the limit frequency and the prime mover 14 may malfunction and stop. An example of such a rapid increase in load is a power outage. In the charge/discharge control device 28, for example, upon receiving a self-sustained operation instruction and, for example, when the premises frequency reaches the lower limit level (establishment of a predetermined condition), the above-mentioned "load rapid increase" is recognized, and the power generation unit 16 generates power. In order to compensate for the above, discharge control of the power storage unit 12 is performed.

In the following, the control of the charge/discharge control device 28 will be described by taking a sudden increase in load as an example. ), if the charging control of the power storage unit 12 is performed, it is possible to perform the same control as when the load suddenly increases.

The charge/discharge control device 28 instructs the power storage unit 12 to discharge when the frequency of the power generation unit 16 exceeds a predetermined limit frequency.

In addition, the charge/discharge control device 28 performs control to decrease the amount of discharge from the power storage unit 12 as the output of the prime mover 14 increases.

That is, in the charge/discharge control device 28, when an instantaneous load fluctuation (increase in this case) occurs, the rapid response characteristic of the power storage unit 12 is utilized to store power so as not to exceed the upper limit of the characteristic of the prime mover 14. It controls the discharge amount of the unit 12 .

Here, the power generation system used in the cogeneration system generally has a tolerance for load fluctuation characteristics (instantaneous load fluctuations), and cannot cope with instantaneous load fluctuations that exceed the characteristics during isolated operation due to system separation.

Therefore, in the present embodiment, when the load on the power generation unit 16 increases (or decreases), the frequency of the power generation unit 16 is detected, and based on the frequency determined from the allowable amount for the load fluctuation characteristics of the prime mover 14, the electric power By performing control to discharge (or charge) the storage unit 12, it is possible to prevent the engine 14 from abnormally operating and stopping due to an instantaneous load change.

By the way, the power generation unit 10 of the present embodiment includes the droop control section 18 as described above, and depending on the output of the power generation section 16, the target frequency is adjusted by the droop control, and the target frequency during operation after a rapid increase in load is adjusted. The frequency may deviate from the frequency to accommodate the total power consumption (power requirement) of the load.

Due to this frequency shift, the generated power of the power generation unit 16 is stabilized at a small amount of generated power with respect to the required amount of power (occurrence of an offset corresponding to the frequency shift (see FIG. 6)).

Due to this offset, the electric power storage unit 12 continues to discharge. For example, the electric power stored in the electric power storage unit 12 temporarily becomes 0 (storage amount 0), and a subsequent discharge request can be quickly responded to. It may lead to a situation that cannot be done.

Therefore, in the present embodiment, attention is paid to a table that is set based on the frequency-charge/discharge control characteristics (see FIG. 4) in the power storage unit 12 and stored in a storage medium (not shown) of the charge/discharge control device 28. , the charging and discharging timings of the power storage unit 12 are adjusted according to the change in the target frequency.

(Details of charge/discharge timing adjustment)

FIG. 4 is a frequency-charging/discharging control characteristic diagram corresponding to a table stored in a storage medium (not shown) of the charging/discharging control device 28. As shown in FIG.

As shown in FIG. 4, the frequency at which the power generated by the power generation unit 16 and the power required by the load 22 match is set as the zero-cross point frequency at which charging and discharging are not performed (see point A in FIG. 4). ), when the frequency is lower than the zero-cross point frequency (point A), the battery is discharged (see hatched area B in FIG. 4), and when the power generation is excessive, the frequency is higher than the zero-cross point frequency (point A). 4, shaded area C).

This zero-cross point frequency (point A) is set under the droop control function based on the default target frequency of the droop control function. In other words, by controlling the frequency of the power generation unit 16 to the target frequency, the power generated by the power generation unit 16 matches the power required by the load. , the frequency of the power generation unit 16 at this time becomes the zero-cross point frequency (point A).

However, for example, due to a power outage or the like, the power required by the load 22 rises sharply during system self-sustaining control immediately after the power supply to the load 22 drops. may be dealt with by discharging the power of

Due to this sudden power generation of the power generation unit 16, the target frequency is set low by droop control, and the power generated by the power generation unit 16 stabilizes without reaching the power required by the load 22. Discharge of the portion 12 is continued.

Therefore, the zero-cross point frequency in FIG. 4 is shifted to follow the change in the target frequency due to droop control. For example, in the situation where the electric power storage unit 12 continues to discharge as described above, the zero-cross point frequency point A is shifted to the lower frequency side (for example, the point D).

As a result, even if the frequency during power generation of the power generation unit 16 is stabilized in a low state, the discharge of the power storage unit 12 is completed at the low frequency. The unit 16 can generate power by increasing the frequency.

By stabilizing the power generation of the power generation unit 16, the target frequency gradually returns to the default value before the power failure, and after that, the control state before the power failure is maintained.

The operation of this embodiment will be described below.

(Energy storage unit charge/discharge control)

FIG. 3A is a flow chart showing a charging/discharging control routine for determining switching timing between charging and discharging according to power generation of the power generation unit 16, which is executed in the power storage unit 12. FIG.

At step 50 , the frequency is extracted according to the power generation of the power generation section 16 , then the process proceeds to step 52 to compare the extracted frequency and the zero-cross point frequency, and the process proceeds to step 54 .

At step 54, the process branches depending on the result of the comparison at step 52. FIG.

That is, if it is determined at step 54 that the extracted frequency is equal to the zero-crossing point frequency, the routine proceeds to step 56, where charging and discharging are not performed, and this routine ends.

If it is determined at step 54 that the extracted frequency>the zero-crossing point frequency, the process proceeds to step 58 to execute the switching process to charging, and this routine ends.

Further, when it is determined at step 54 that the extraction frequency<the zero-crossing point frequency, the routine proceeds to step 60 to execute a switching process to discharge, and this routine ends.

(Discharge control during sudden load increase)

FIG. 3B is a flow chart showing a power generation/discharge control routine during grid isolation when the load of the power generation unit 16 suddenly increases.

When the power generation/discharge control during system isolation based on the instruction for isolated operation is started, in step 100, when the in-plant frequency reaches the lower limit level, the power storage unit 12 starts discharging, and the process proceeds to step 102.

At step 102, it is determined whether or not the local frequency has returned to a predetermined level or higher. Specifically, it is a measure to wait until the frequency stabilizes.

If a negative determination is made in step 102 , the process proceeds to step 104 . A step 104 determines whether or not a predetermined period of time has elapsed, and returns to the step 102 if a negative determination is made. Further, when the determination in step 104 is affirmative, it is considered that there is another reason why the in-plant frequency does not return to a stable predetermined frequency or higher (for example, insufficient remaining capacity of the power storage unit 12), and the process proceeds to step 106. Then, an error notification is given and this routine ends.

On the other hand, if the determination in step 102 is affirmative, the process proceeds to step 108, and the frequency-charge/discharge control characteristic (see FIG. 4) of the power storage unit 12 is corrected according to the target frequency. For example, in FIG. 4, a correction is performed to shift the default zero-cross point frequency (point A) to point B in order to end the discharge earlier. Specifically, the data based on the frequency-charge/discharge control characteristics (see FIG. 4) stored in the storage medium of the charge/discharge control device 28 is updated.

The shift control of the zero cross point frequency in this frequency-charge/discharge control characteristic (see FIG. 4) makes it possible to avoid wasteful charging/discharging in the power storage unit 12, and the necessary and sufficient power required by the load 22 is supplied to the power generation unit. 16 can generate electricity.

(Example)

FIG. 5 shows changes in the power generated by the power generation unit 16 and the power discharged from the power storage unit 12 based on load fluctuations (passage of time) when the power generation system of the present embodiment is used, and the frequency of the power generation unit 16. It is an example of a characteristic diagram showing the transition of .

The origin of the time axis (horizontal axis) indicates the time when a power failure or the like occurred and the load decreased. Although the power generation unit 16 generates power as the load increases sharply, the power generation unit output cannot cope with the load and the frequency also drops.

On the other hand, the charge/discharge control device 28 instructs discharge from the power storage unit 12 in accordance with the amount of power generated by the power generation unit 16 that is insufficient.

Thereafter, the power consumption of the load is maintained by gradually increasing the power of the power generation unit 16 and decreasing the amount of discharge from the power storage unit 12 when the frequency is restored (switched from decrease to increase). .

If the power generated by the power generation unit 16 reaches the power consumption of the load 22 as it is, the discharge of the power storage unit 12 will end. and the target frequency may be adjusted as the load increases.

As a result, as shown in the comparative example of FIG. 6, the generated power of the power generation unit 16 is stabilized at a small amount of generated power with respect to the required amount of power, and the discharge from the power storage unit 12 is continued. Note that the comparative example of FIG. 6 is a characteristic diagram when the load suddenly increases when the power generation system of the present embodiment is not used.

On the other hand, in the present embodiment, attention is focused on the time zone in which the frequency dependent on the power generation output of the power generation unit 16 is stable at the target frequency, and as shown in FIG. The zero-cross point frequency of the charge/discharge control characteristics (see the frequency-charge/discharge characteristic diagram in FIG. 4) in the unit 12 is shifted based on the target frequency (point A→point D in FIG. 4).

In the case of this embodiment (FIG. 5), the target frequency is lowered by the droop control, so the zero-cross point frequency is shifted leftward on the horizontal axis (frequency axis) of FIG. As a result, the discharge end time is brought forward, so that power generation of the power generation unit 16 is controlled to cover the shortage of power for the load.

(Charging control when the load suddenly decreases)

In the present embodiment, as an example of a sudden change in load, the control of discharging when the load suddenly increases has been described in detail. Since control according to the flowchart of FIG. 3 (for example, (shifting the zero-cross point frequency to the right on the horizontal axis shown in FIG. 4)) may be performed, here, charging control when the load suddenly decreases A detailed description of is omitted.

In this embodiment, the charge/discharge control based on the zero-cross point frequency shift of the frequency-charge/discharge control characteristic of the power storage unit 12 has been described. More specifically, when the load suddenly increases, the power storage unit 12 starts to discharge, and as the power generation amount of the power generation unit 10 increases, the discharge is gradually reduced, and the target that changes by droop control is set. By following the frequency, the zero cross point frequency of the frequency-charge/discharge control characteristic of the power storage unit 12 is shifted (in discharge, shifted to the left in FIG. 4), and the discharge is forcibly terminated, thereby reducing the droop. The configuration is such that the power generation amount is returned to the amount before the sudden load change caused by the control.

On the other hand, the discharge termination time may be adjusted in consideration of the remaining amount of the power storage unit 12 . For example, if the remaining amount is insufficient, discharge is terminated immediately at the zero-cross point frequency, or if the remaining amount is excessive, the discharge is terminated while gradually decreasing the discharge amount from the zero-cross point frequency. It may be set based on the remaining amount of the unit 12 .

10 Power generation unit (private power generator)
REFERENCE SIGNS LIST 12 power storage unit 14 prime mover 16 power generation unit 18 droop control unit 20 output unit 22 load 24 frequency detection unit 26 control unit 28 charge/discharge control device

The charge/discharge control device according to the present invention generates power by driving the prime mover, and when synthesizing the power generated by itself and the power generated by others, changes the target frequency according to the load of the power generation output of itself. a power generator having a droop control function that adjusts the load factor by increasing the load factor; In the device, a frequency at which the power generated by the power generation unit and the power required by the load match is set as a zero-crossing point frequency at which charging and discharging are not performed, and the frequency is lower than the zero-crossing point frequency. A charge/discharge control unit that discharges when power generation is insufficient and charges when power generation is excessive when the frequency is higher than the zero-crossing point frequency, and the charge/discharge control unit controls that the amount of power required by the load exceeds a standard. When the amount of power generated by the power generation unit changes to increase or decrease, and an excess or deficiency occurs in the amount of power generated, the power storage unit is controlled to discharge when power generation by the power generation unit is insufficient and to charge when power generation is excessive. In addition, when the target frequency of the droop control function changes during discharging or charging due to a load fluctuation rate larger than the predetermined steady-state fluctuation rate of the load, the change in the target frequency Accordingly, the zero-cross point frequency is shifted to adjust the end timing of discharging or charging from the power storage unit.

In the present invention , the charge/discharge control unit gradually reduces the discharge or charge from the time when the power storage unit ends the discharge or charge in proportion to the elapsed time from the time. It is characterized in that it is set to the end state.

In the present invention, the charging/discharging control section is characterized in that the charging or discharging is stopped immediately at the time when the charging or discharging by the power storage section is finished.

Claims (6)

Droop control that adjusts the load factor by changing the target frequency according to the load of the self-generated output when generating power by driving the prime mover and synthesizing the power generated by itself and the power generated by others. A charge/discharge control device for controlling charge/discharge of the power storage unit in a private power generation device comprising a power generation unit having a function and an electric power storage unit capable of charging/discharging electric power,
A frequency at which the power generated by the power generation unit and the power required by the load match is set as a zero-cross point frequency at which charging and discharging are not performed, and discharging is performed when power generation is insufficient and the frequency is lower than the zero-cross point frequency. and a charge/discharge control unit that charges when excessive power generation occurs at a frequency higher than the zero-crossing point frequency,
The charge/discharge control unit
When the amount of power required by the load increases or decreases beyond a reference level, and the amount of power generated by the power generation unit becomes insufficient or excessive, the power storage unit is controlled to increase or decrease the amount of power generated by the power generation unit. When the power generation is insufficient, the battery is discharged, and when the power generation is excessive, the battery is charged. When the target frequency of the droop control function changes during discharging or charging, the zero cross point frequency is shifted according to the change in the target frequency. to adjust the end timing of discharging or charging from the power storage unit,
Charge/discharge controller. Under the condition that the charge/discharge control unit self-generates,
When the power required by the load increases more than a predetermined amount and the target frequency of the droop control function changes to lower, the zero-cross point frequency is shifted to the lower frequency side, and the load requires 2. The charge/discharge control device according to claim 1, wherein the zero-crossing point frequency is shifted to a higher frequency side when the power to be supplied suddenly decreases by a predetermined amount or more and the target frequency of the droop control function changes to become higher. The charge/discharge control unit
A table for controlling charging and discharging in the power storage unit according to the frequency corresponding to the power generated by the power generation unit,
3. The charge/discharge control device according to claim 1, wherein said zero-cross point frequency in said table is updated based on a default target frequency of said droop control function. 4. The charge/discharge control unit according to any one of claims 1 to 3, wherein from the time when the discharge or charge by the power storage unit by the charge/discharge control unit is to be terminated, the power is gradually decreased in proportion to the elapsed time to reach the termination state. 2. The charge/discharge control device according to claim 1. 4. The charge/discharge control device according to any one of claims 1 to 3, wherein the charge/discharge control unit stops discharging immediately at the time when the charge/discharge control unit terminates discharging or charging by the power storage unit. the computer,
Operate as the charge/discharge control unit according to any one of claims 1 to 5,
Charge/discharge control program.

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