JP2020150740A - Power supply system - Google Patents

Abstract

To provide a power supply system capable of suppressing deterioration of discharge efficiency of a storage battery.SOLUTION: A power supply system includes: a plurality of storage batteries 22, 32, 42, and 52 which can discharge a power to each housing H; and an EMS 60 that controls the discharge of the storage batteries 22, 32, 42, and 52. The EMS 60 reduces a discharge power of each storage battery excluding a part of the storage batteries when the discharge power of a part of the storage batteries 22, 32, 42, and 52 from two or more of storage batteries 22, 32, 42, and 52 that discharge the power is less than a discharge reference value set in consideration of a discharge efficiency of the storage batteries 22, 32, 42, and 52.SELECTED DRAWING: Figure 6

Description

The present invention relates to a technique of a power supply system including a plurality of storage batteries capable of discharging electric power to a load.

Conventionally, a technique of a power supply system including a plurality of storage batteries capable of discharging power to a load has been known. For example, as described in Patent Document 1.

The power supply system described in Patent Document 1 includes a plurality of tracking sensors and a plurality of power storage devices (storage batteries). A plurality of tracking sensors are provided so as to correspond to a plurality of power storage devices (one for one power storage device). The plurality of power storage devices are connected to distribution lines connecting the system power supply and the plurality of houses (loads) so as to line up in the distribution direction of the electric power. At the time of discharging, the power storage device performs a load following operation in which the discharge power is adjusted according to the detection result of the corresponding tracking sensor. The power supply system can interchange power between the houses by supplying the power discharged from the plurality of power storage devices to the plurality of houses via the distribution line.

The power storage device described in Patent Document 1 loses a part of electric power at the time of discharging (for example, when converting DC electric power into AC electric power). If the discharge efficiency evaluated for the degree of this loss is 90%, a loss of 10% will occur with respect to the charging power of the power storage device. The discharge efficiency deteriorates as the discharge power of the power storage device decreases (see FIG. 2).

Since the power supply system described in Patent Document 1 does not consider the influence of such discharge efficiency, there is a possibility that the discharge power becomes small and the discharge efficiency deteriorates. In this case, the loss of electric power tends to increase, and there is a possibility that the electric power cannot be used effectively.

JP-A-2018-571152

The present invention has been made in view of the above circumstances, and the problem to be solved is to provide a power supply system capable of suppressing deterioration of the discharge efficiency of the storage battery.

The problem to be solved by the present invention is as described above, and next, the means for solving this problem will be described.

That is, in claim 1, a plurality of storage batteries capable of discharging power to a load and a control unit for controlling the discharge of the storage batteries are provided, and the control unit is among two or more storage batteries to be discharged. When the discharge power of some of the storage batteries is less than the reference value set in consideration of the discharge efficiency of the storage batteries, the discharge power of the storage batteries excluding some of the storage batteries is reduced.

In the second aspect, the control unit reduces the discharge power by setting a discharge upper limit value which is an upper limit value of the discharge power of the storage battery, and is equal to or more than the reference value and of the storage battery. The discharge upper limit value is set so that the value is less than the maximum discharge power.

In claim 3, the reference value includes a plurality of discharge reference values having different values, and the control unit compares the discharge power of some of the storage batteries with the plurality of discharge reference values. The discharge upper limit value is set so that the value is equal to or higher than the discharge power and is equal to or higher than the discharge reference value closest to the discharge power.

In claim 4, the storage battery is set with a priority regarding discharge, and the control unit sets the discharge upper limit value so that the storage battery having the higher priority has a higher discharge upper limit value. is there.

In claim 5, the control unit assumes that the same number of discharged batteries as the number of discharged batteries is discharged with the same discharge power as the reference value, and the distributed discharge power is insufficient for the load. Is calculated, the distribution value which is the value obtained by preferentially distributing the power of the distributed discharge power to the storage battery having the higher priority is calculated, and the reference value and the distribution value are added up to obtain the discharge upper limit value. Is calculated.

In claim 6, the plurality of storage batteries are connected in series with each other in a power supply path connecting the system power supply and the load, and the control unit is the most system among the two or more storage batteries to be discharged. The discharge upper limit value is not set for the storage battery close to the power source.

As the effect of the present invention, the following effects are exhibited.

In claim 1, it is possible to suppress deterioration of the discharge efficiency of the storage battery.

In claim 2, it is possible to mitigate the influence of deterioration of the discharge efficiency of the storage batteries other than some storage batteries caused by setting the discharge upper limit value.

In claim 3, it is possible to effectively mitigate the influence of deterioration of the discharge efficiency of the storage batteries other than some storage batteries caused by setting the discharge upper limit value.

In claim 4, the discharge upper limit value can be optimized according to the priority.

In claim 5, the discharge upper limit value can be easily calculated according to the priority.

In claim 6, it is possible to cope with a rapid increase in load power consumption.

A block diagram showing a power supply system. A graph showing the relationship between discharge power and discharge efficiency. In case C1, a block diagram showing a state before executing the main flow. A flowchart showing the main flow. The flowchart which showed the process of the discharge instruction with the discharge upper limit value. In case C1, a block diagram showing a state after executing the main flow. In case C2, the block diagram which showed the state before executing the main flow. In case C2, the block diagram which showed the state after executing the main flow.

Hereinafter, the power supply system 1 according to the present embodiment will be described with reference to FIG.

It is assumed that the power supply system 1 is applied to a residential block T (aggregate of houses H) composed of a plurality of detached houses (houses H). Specifically, in the residential block T, a first house H1, a second house H2, a third house H3, and a fourth house H4 are provided as a plurality of (detached) houses H. In the residential district T, the electric power retailer purchases electric power from the electric power company (system power source S) in a lump sum, and the purchased electric power is appropriately supplied (sold) to each house H.

The electric power supply system 1 is a system for appropriately supplying (accommodating) electric power and the like purchased in bulk from an electric power company among a plurality of houses H (first house H1 to fourth house H4) by an electric power retailer. The power supply system 1 mainly includes a sensor unit 10, a first power storage system 20, a second power storage system 30, a third power storage system 40, a fourth power storage system 50, and an EMS 60.

The plurality of houses H (first house H1 to fourth house H4) are buildings in which people live. An appropriate electric product is provided in each house H, and electric power is consumed.

Further, each house H is connected to the grid power supply S. Specifically, each house H is connected to the system power supply S via a distribution line L whose upstream end is connected to the system power supply S and whose downstream end is branched and connected to each house H. Be connected.

The sensor unit 10 detects the electric power flowing through the distribution line L. The sensor unit 10 includes a first sensor 11, a second sensor 12, a third sensor 13, and a fourth sensor 14.

The first sensor 11, the second sensor 12, the third sensor 13, and the fourth sensor 14 each detect the electric power flowing through the arrangement location. The first sensor 11, the second sensor 12, the third sensor 13, and the fourth sensor 14 are configured to be capable of outputting signals related to the detection results, respectively. The first sensor 11, the second sensor 12, the third sensor 13, and the fourth sensor 14 are each provided so as to correspond to a predetermined power storage system, and are electrically connected to the hybrid power conditioner of the corresponding power storage system.

Specifically, the first sensor 11 is electrically connected to the hybrid power conditioner 23 of the first power storage system 20, which will be described later. Further, the second sensor 12 is electrically connected to the hybrid power conditioner 33 of the second power storage system 30, which will be described later. Further, the third sensor 13 is electrically connected to the hybrid power conditioner 43 of the third power storage system 40, which will be described later. Further, the fourth sensor 14 is electrically connected to the hybrid power conditioner 53 of the fourth power storage system 50, which will be described later.

Further, the first sensor 11, the second sensor 12, the third sensor 13, and the fourth sensor 14 are arranged on the distribution line L immediately upstream of the connection point to which the hybrid power conditioner of the corresponding power storage system is connected. To. Specifically, the first sensor 11, the second sensor 12, the third sensor 13, and the fourth sensor 14 have the first connection point P1, the second connection point P2, and the third connection point, which will be described later, in the distribution line L, respectively. It is arranged immediately upstream of P3 and the fourth connection point P4.

The first power storage system 20, the second power storage system 30, the third power storage system 40, and the fourth power storage system 50 are each connected to the distribution line L. More specifically, the first power storage system 20, the second power storage system 30, the third power storage system 40, and the fourth power storage system 50 are connected in order from each house H side to the system power supply S side in the distribution line L. Are connected in series with each other. The first power storage system 20, the second power storage system 30, the third power storage system 40, and the fourth power storage system 50 are owned by the residents of the first house H1, the second house H2, the third house H3, and the fourth house H4, respectively. Has been done. Specifically, the first power storage system 20 is provided in the first house H1 and is owned by the resident of the first house H1. Further, the second power storage system 30 is provided in the second house H2 and is owned by the resident of the second house H2. Further, the third power storage system 40 is provided in the third house H3 and is owned by the resident of the third house H3. Further, the fourth power storage system 50 is provided in the fourth house H4 and is owned by the resident of the fourth house H4.

The first power storage system 20 stores power purchased from the grid power source S or power generated by using sunlight, and supplies the power to each house H or the like. The first power storage system 20 includes a solar power generation unit 21, a storage battery 22, and a hybrid power conditioner 23.

The photovoltaic power generation unit 21 is a device that uses sunlight to generate electricity. The photovoltaic power generation unit 21 is composed of a solar cell panel or the like. The photovoltaic power generation unit 21 is installed in a sunny place such as on the roof of a house. The photovoltaic power generation unit 21 is connected to the distribution line L at a first connection point P1 provided in the middle of the distribution line L via a hybrid power conditioner 23 described later.

The storage battery 22 is configured to be able to charge and discharge electric power. The storage battery 22 is composed of, for example, a lithium ion battery. The storage battery 22 is connected to the photovoltaic power generation unit 21 via a hybrid power conditioner 23 described later. In the present embodiment, the storage battery 22 has a maximum discharge power (maximum value of power that can be discharged per unit time) of 2000 W.

The hybrid power conditioner 23 is a device (hybrid power conditioner) that appropriately converts electric power. The hybrid power conditioner 23 is configured to be able to charge the storage battery 22 with the electric power generated by the photovoltaic power generation unit 21 and the electric power from the grid power source S. Further, the hybrid power conditioner 23 discharges the electric power generated by the photovoltaic power generation unit 21 and the electric power charged in the storage battery 22 to each house H or the like. Further, the hybrid power conditioner 23 is configured to be able to acquire information on the operating state of the photovoltaic power generation unit 21 and the storage battery 22. Such a hybrid power conditioner 23 is connected to the middle portion of the distribution line L at the first connection point P1.

The hybrid power conditioner 23 of the first power storage system 20 configured in this way is configured so that a predetermined signal can be input from the corresponding sensor (first sensor 11), and the detection result of the sensor can be acquired based on the signal. It is composed. The hybrid power conditioner 23 can perform a load following operation for adjusting the discharge power of the storage battery 22 based on the detection result of the acquired sensor and the like.

The second power storage system 30 is different from the first power storage system 20 except that the hybrid power conditioner 33 is connected to the distribution line L at the second connection point P2 provided on the system power supply S side of the first connection point P1. It is configured in the same way. Specifically, the photovoltaic power generation unit 31, the storage battery 32, and the hybrid power conditioner 33 of the second power storage system 30 correspond to the photovoltaic power generation unit 21, the storage battery 22, and the hybrid power conditioner 23 of the first power storage system 20, respectively.

The third power storage system 40 is different from the first power storage system 20 except that the hybrid power conditioner 43 is connected to the distribution line L at the third connection point P3 provided on the system power supply S side of the second connection point P2. It is configured in the same way. Specifically, the photovoltaic power generation unit 41, the storage battery 42, and the hybrid power conditioner 43 of the third power storage system 40 correspond to the photovoltaic power generation unit 21, the storage battery 22, and the hybrid power conditioner 23 of the first power storage system 20, respectively.

The fourth power storage system 50 is different from the first power storage system 20 except that the hybrid power conditioner 53 is connected to the distribution line L at the fourth connection point P4 provided on the system power supply S side of the third connection point P3. It is configured in the same way. Specifically, the photovoltaic power generation unit 51, the storage battery 52, and the hybrid power conditioner 53 of the fourth power storage system 50 correspond to the photovoltaic power generation unit 21, the storage battery 22, and the hybrid power conditioner 23 of the first power storage system 20, respectively.

The EMS 60 is an energy management system (Energy Management System) that manages the operation of the power supply system 1. The EMS 60 includes an arithmetic processing unit such as a CPU, a storage unit such as a RAM or ROM, an input / output unit such as a touch panel, and the like, and can perform predetermined arithmetic processing, storage processing, and the like. Various information, programs, and the like used when controlling the operation of the power supply system 1 are stored in advance in the EMS 60.

Further, the EMS 60 is electrically connected to the hybrid power conditioners 23, 33, 43, 53 of each power storage system 20, 30, 40, 50. The EMS 60 outputs a predetermined signal to the hybrid power conditioner 23, 33, 43, 53, and issues a charge / discharge instruction to the storage batteries 22, 32, 42, 52 via the hybrid power conditioner 23, 33, 43, 53. , The charging / discharging of the storage battery 22, 32, 42, 52 can be permitted. Further, the EMS 60 outputs a predetermined signal to the hybrid power conditioner 23, 33, 43, 53, and instructs the storage battery 22, 32, 42, 52 to stand by via the hybrid power conditioner 23, 33, 43, 53. It is possible to prohibit the charging and discharging of the storage batteries 22, 32, 42, and 52.

Further, the EMS 60 can set a discharge upper limit value, which is an upper limit value of the discharge power of the storage batteries 22, 32, 42, 52, by outputting a predetermined signal to the hybrid power conditioner 23, 33, 43, 53. For example, when the discharge upper limit value of the storage battery 22 is set to 1500 W, the storage battery 22 can only discharge up to 1500 W even though the maximum discharge power is 2000 W. In this way, the EMS 60 can reduce the discharge power of the storage batteries 22, 32, 42, and 52.

Further, the EMS 60 is configured so that a predetermined signal can be input from the hybrid power conditioner 23, 33, 43, 53. As a result, the EMS 60 can detect the generated power of the photovoltaic power generation unit 21, 31, 41, 51 via the hybrid power conditioner 23, 33, 43, 53.

Further, the EMS 60 is electrically connected to each house H. The EMS 60 is configured so that a predetermined signal can be input from each house H. As a result, the EMS 60 can acquire the power consumption of each house H.

Further, the EMS 60 is capable of executing control for setting the discharge priority of the storage batteries 22, 32, 42, and 52, respectively. In the present embodiment, the discharge priority is the discharge priority of the storage batteries 22, 32, 42, and 52 in each of the power storage systems 20, 30, 40, and 50.

Next, the state of buying and selling electric power by the electric power retailer in the electric power supply system 1 configured as described above will be briefly described.

The electric power retailer appropriately sells the electric power purchased in bulk from the electric power company (grid power source S) to each house H in response to a request from each house H. The resident of each house H can use the electric power purchased from the electric power company through the electric power retailer. Further, the electric power retailer purchases the electric power discharged from each of the power storage systems 20, 30, 40, and 50, and appropriately sells the electric power to each house H in response to a request from each house H. The price of electricity bought and sold by the electricity retailer is set appropriately.

In this way, electricity retailers can profit from buying and selling electricity. In addition, the residents of each house H can also make a profit by selling the electric power (that is, surplus electric power) of each power storage system 20, 30, 40, 50 to the electric power retailer.

In the following, the control of each power storage system 20, 30, 40, 50 performed by the EMS 60 will be described. In the following, the control of each power storage system 20, 30, 40, 50 will be described assuming that the discharge upper limit value is not set.

The EMS 60 supplies the electric power from the photovoltaic power generation units 21, 31, 41, 51 to each house H with priority over the storage batteries 22, 32, 42, 52. Specifically, the EMS 60 first supplies the electric power from the photovoltaic power generation units 21, 31, 41, 51 to each house H via the distribution line L. When the power from the photovoltaic power generation unit 21, 31, 41, 51 cannot cover the power consumption (total power consumption) of each house H, the EMS 60 uses the power from the storage batteries 22, 32, 42, 52. Supply to each house H. At this time, the EMS 60 discharges the storage batteries having the highest discharge priority in order.

As described above, the discharge priority is the discharge priority of the storage batteries 22, 32, 42, and 52 in each of the power storage systems 20, 30, 40, and 50. The EMS 60 acquires the cumulative discharge amount of the storage batteries 22/32/42/52 on the previous day via the hybrid power conditioners 23, 33, 43, and 53, and sets the discharge priority in order from the one with the smallest integrated discharge amount. .. In this way, the EMS 60 sets the discharge priority so that the power storage system having a small integrated discharge amount of the storage batteries 22, 32, 42, and 52 is ranked higher. The EMS 60 is configured to set such a discharge priority at a fixed timing (for example, at 0 o'clock).

The EMS 60 discharges in order from the storage battery having the higher discharge priority (the integrated discharge amount is smaller) set in this way. Specifically, the EMS 60 first issues a discharge instruction to the storage battery having the highest discharge priority via the hybrid power conditioner, and discharges the storage battery. At this time, the discharge power of the storage battery having the highest discharge priority is adjusted by the load following operation.

Further, the EMS 60 discharges the storage battery having the second highest discharge priority when the power consumption of each house H cannot be covered even if the storage battery having the highest discharge priority is discharged. At this time, the discharge power of the storage battery having the second highest discharge priority is adjusted by the load following operation.

As described above, when the power consumption of each house H cannot be covered, the EMS 60 repeatedly performs the operation of discharging the storage battery having a discharge priority one lower than that of the storage battery from which the discharge is started.

According to this, the EMS 60 can increase the chances that the (upper) storage battery having a small integrated discharge amount is discharged as compared with other storage batteries, and can equalize the integrated discharge amount of these storage batteries. If the power consumption of each house H cannot be covered even if all the storage batteries 22, 32, 42, and 52 are discharged, the insufficient power is purchased from the grid power supply S (purchased from the grid power supply S). The generated power is supplied to each house H).

Further, when the storage battery 22 of the first power storage system 20 on the most downstream side of the power storage systems 20, 30, 40, and 50 is discharged, it is arranged not only on the first sensor 11 but also on the upstream side of the first sensor 11. The values of the detection results of the second sensor 12, the third sensor 13, and the fourth sensor 14 are also reduced. Further, when the storage battery 32 of the second power storage system 30 is discharged, not only the second sensor 12 but also the detection result values of the third sensor 13 and the fourth sensor 14 arranged on the upstream side of the second sensor 12 are also displayed. It becomes smaller. Further, the storage battery on the downstream side is discharged when the storage battery on the upstream side cannot cover the power consumption of each house H even if it is discharged at the maximum discharge power (2000 W). As a result, when a plurality of storage batteries are discharged, the storage batteries other than the most upstream side (close to the system power supply S) of the discharged storage batteries are discharged at the maximum discharge power (2000 W), and the most upstream side. The storage battery will discharge less than the maximum discharge power (see FIG. 7). In this way, when a plurality of storage batteries are discharged, the discharge power of the most upstream storage battery becomes smaller than the discharge power of the other storage batteries.

Further, in the power supply system 1, the electric power discharged from each power storage system 20/30/40/50 is supplied to each house H via the distribution line L, so that each power storage system 20/30/40. It will be supplied not only to the resident who owns 50 (house H) but also to other residents (house H). That is, the electric power discharged from each of the power storage systems 20, 30, 40, and 50 is appropriately exchanged between the plurality of houses H. As a result, even if the power consumption of the own house H (for example, the first house H1) is small, the own house H is used to cover the power consumption of the other houses H (second house H2 to fourth house H4). The storage battery (storage battery 22) installed in the above can be discharged. As a result, the storage batteries 22, 32, 42, and 52 can be easily discharged, and the discharge opportunities of the storage batteries 22, 32, 42, and 52 can be increased.

In the following, the relationship between the discharge power of the storage batteries 22, 32, 42, and 52 and the discharge efficiency will be described.

The storage batteries 22, 32, 42, and 52 lose a part of electric power at the time of discharging (for example, when converting DC electric power into AC electric power). If the discharge efficiency evaluated for the degree of this loss is 90%, a loss of 10% will occur with respect to the charging power of the storage batteries 22, 32, 42, and 52. As shown in FIG. 2, the discharge efficiency deteriorates as the discharge power of the storage batteries 22, 32, 42, and 52 becomes smaller. Note that FIG. 2 shows an example of the relationship between the discharge power and the discharge efficiency, and the relationship differs depending on the types of the storage batteries 22, 32, 42, and 52.

As described above, when a plurality of storage batteries are discharged, the discharge power of the most upstream storage battery among the discharged storage batteries becomes smaller than the discharge power of the other storage batteries. Therefore, if no special treatment is performed, the discharge power of the storage battery on the most upstream side may become too small, and the discharge efficiency of the storage battery may deteriorate. FIG. 3 shows the state.

In the state shown in FIG. 3, the discharge priority is as follows: the storage battery 52 is the first, the storage battery 42 is the second, the storage battery 32 is the third, and the storage battery 22 is the fourth. The total power consumption of each house H is 2400 W. Further, in FIG. 3, for convenience of explanation, it is assumed that the photovoltaic power generation units 21, 31, 41, and 51 do not generate power (the generated power is 0 W).

In the above state, the total power consumption (2400W) of each house H cannot be covered unless the two storage batteries 42 and 52 having the highest discharge priority are discharged. Therefore, the EMS60 has two storage batteries. Issue a discharge instruction to 42.52. As a result, the storage battery 42 on the downstream side is discharged at the maximum discharge power (2000 W), and the storage battery 52 on the upstream side is discharged at 400 W.

As shown in FIG. 2, the storage battery 42 that discharges at the maximum discharge power (2000 W) has a discharge efficiency of about 90%. Therefore, the storage battery 42 has a loss of about 10% when discharged. On the other hand, the storage battery 52 that discharges at 400 W has a discharge efficiency of about 80%. Therefore, in the storage battery 52, the loss generated at the time of discharging increases to about 20% (about 10% increases as compared with the case of discharging with the maximum discharge power).

As described above, in the power supply system 1, if the storage battery 42 on the downstream side is discharged with the maximum discharge power (2000 W), the discharge efficiency of the storage battery 52 on the most upstream side depends on the total power consumption of each house H. May get worse. Therefore, in the EMS 60 according to the present embodiment, the discharge upper limit value is appropriately set according to the main flow shown in FIG. 4, and the deterioration of the discharge efficiency is suppressed.

The main flow will be described below.

The main flow is the main flow of the process for setting the discharge upper limit value. The processing of the main flow is performed at a fixed timing (for example, every minute). In the following, the specific contents of the main flow processing will be described with reference to FIG.

First, in step S110, the EMS 60 acquires the total power consumption A and the total photovoltaic power generation B. The total power consumption A is the total power consumption of each house H. The EMS 60 acquires the total power consumption A by acquiring the power consumption from the first house H1 to the fourth house H4 and summing the results. Further, the total photovoltaic power generation B is the total power generated by the photovoltaic power generation units 21, 31, 41, 51. The EMS60 acquires the power generated by the photovoltaic power generation units 21, 31, 41, and 51 via the hybrid power conditioners 23, 33, 43, and 53, respectively, and totals the results to acquire the total photovoltaic power generation B. To do. When the process of step S110 is completed, the EMS 60 shifts to step S120.

In step S120, the EMS 60 determines whether the total power consumption A is larger than the total photovoltaic power generation B. The EMS 60 shifts to step S150 when the total power consumption A is larger than the total photovoltaic power generation power B (step S120: YES). On the other hand, the EMS 60 shifts to step S130 when the total power consumption A is equal to or less than the total photovoltaic power generation power B (step S120: NO).

In step S130, the EMS 60 calculates the number of charge instructions D, which is the number of storage batteries to be charged. In step S130, since the total power consumption A is equal to or less than the total photovoltaic power generation B, the total power generated by the photovoltaic power generation units 21, 31, 41, and 51 becomes the total power consumption of each house H. On the other hand, it is in a surplus state. Therefore, in order to charge the storage battery 22.32.42.52 with the surplus power (BA), the EMS60 first uses the surplus power (BA) to determine which of the storage batteries 22.32.42.52. Whether or not the storage battery of the unit can be charged is calculated by the following formula (1).
D = (BA) / C ... (1)
Here, in the above formula (1), C is the maximum charging power of the storage batteries 22, 32, 42, and 52.

In the above equation (1), D may not be an integer. In this case, the EMS 60 calculates the number of charging instructions D by rounding up the decimal point of D. Further, in the above formula (1), D may exceed the total number of storage batteries 22, 32, 42, 52 (“4”). In this case, the EMS 60 substitutes the total number of storage batteries 22, 32, 42, and 52 (“4”) into the charging instruction number D. When the process of step S130 is completed, the EMS 60 shifts to step S140.

In step S140, the EMS 60 issues a charging instruction to the D units of the storage batteries. At this time, the EMS 60 acquires the remaining amount of the storage batteries 22, 32, 42, and 52, respectively, via the hybrid power conditioners 23, 33, 43, and 53, and issues a charging instruction to the D storage batteries in ascending order. .. Further, the EMS 60 issues a standby instruction to other storage batteries. When the process of step S140 is completed, the EMS 60 ends the process of the main flow.

In step S150, the EMS 60 calculates the number of discharge instructions F, which is the number of storage batteries to be discharged. The number of discharge instructions F is a value indicating how many storage batteries are discharged when the storage batteries are discharged without setting the discharge upper limit value (as shown in FIG. 3). The EMS 60 calculates the discharge instruction number F by the following formula (2).
F = (AB) / E ... (2)
Here, in the above formula (2), E is the maximum discharge power (2000 W) of the storage batteries 22, 32, 42, and 52. Further, (AB) is an electric power in which the total photovoltaic power generation power B is insufficient with respect to the total power consumption A. The electric power (AB) is the electric power that needs to be discharged from the storage batteries 22, 32, 42, and 52. Therefore, in the following, the electric power (AB) is referred to as "required total discharge power (AB)".

In the above equation (2), F may not be an integer. In this case, the EMS 60 calculates the discharge instruction number F by rounding up the decimal point of F. Further, in the above formula (2), F may exceed the total number of storage batteries 22, 32, 42, 52 (“4”). In this case, the EMS 60 substitutes the total number (“4”) of the storage batteries 22, 32, 42, and 52 into the discharge instruction number F. When the process of step S150 is completed, the EMS 60 shifts to step S160.

In step S160, the EMS 60 determines whether or not the discharge instruction number F is “1”. The EMS 60 shifts to step S170 when the number of discharge instructions F is “1” (step S160: YES). On the other hand, the EMS 60 shifts to the step S180 when the discharge instruction number F is not “1” (step S160: NO).

In step S170, the EMS 60 issues a discharge instruction to the storage battery having the highest discharge priority, and issues a standby instruction to the other storage batteries. Further, the EMS 60 does not set a discharge upper limit value for the storage battery having the first discharge priority. As a result, the EMS 60 discharges only the storage battery having the highest discharge priority in a state where it can be discharged up to the maximum discharge power E (2000 W). When the process of step S170 is completed, the EMS 60 ends the process of the main flow.

In step S180, EMS60, when was discharged F stand battery without setting the discharge limit, the discharge power is determined whether there is a battery to be less than the discharge reference value G _1. The discharge reference value G ₁ is a value for determining whether or not to set the discharge upper limit value. The discharge reference value G ₁ is appropriately set based on the relationship between the discharge power and the discharge efficiency shown in FIG. In FIG. 2, as the discharge power decreases from 1000 W, the discharge efficiency deteriorates sharply. Further, when the discharge power becomes 1000 W, the discharge efficiency becomes less than 90%, which was exceeded when discharging at the maximum discharge power (2000 W). Therefore, in the present embodiment, the discharge reference value G ₁ 1000W (more discharge power is decreased as the discharge efficiency value sharply deteriorated, the value equal to or less than a predetermined discharge efficiency) is set.

As described above, when a plurality of storage batteries are discharged, the storage batteries other than the most upstream storage battery (F-1) among the discharged storage batteries are discharged at the maximum discharge power E (2000W), and the most upstream side. The storage battery will discharge less than the maximum discharge power (the least power). Therefore, EMS60, in step S180 shown in FIG. 4, the discharge power of the most upstream side of the storage battery or is less than the discharge reference value _{G 1,} it is determined by the following equation (3).
(AB- (E × (F-1))) <G ₁ ... (3)

EMS60 determines that there is a storage battery discharge power is less than the discharge reference value _{G 1} when the equation (3) is satisfied (step S180: YES), the process proceeds to step S190. Meanwhile, EMS60, the above formula (3) is determined to discharge power is no battery to be less than the discharge reference value _{G 1} when not satisfied (step S180: NO), the process proceeds to step S210.

In step S190, EMS60 substitutes the value of the discharge reference value _{G 1} to discharge reference value G. The discharge reference value G is a value for defining the minimum line of the discharge upper limit value in step S200 described later. When the process of step S190 is completed, the EMS 60 shifts to step S200.

In step S200, the EMS 60 executes a discharge instruction subroutine with a discharge upper limit value. In the subroutine, the EMS 60 sets the discharge upper limit value so as to be equal to or higher than the discharge reference value G (with the discharge reference value G as the minimum line) and discharges the storage battery. The subroutine will be described later. When the process of step S200 is completed, the EMS 60 ends the process of the main flow.

In step S210, EMS60 the discharge power is determined whether there is a battery to be less than the discharge reference value _{G 2.} The discharge reference value G ₂ is a value for determining whether or not to set the discharge upper limit value. The discharge reference value G ₂ is appropriately set based on the relationship between the discharge power and the discharge efficiency shown in FIG. Further, the discharge reference value G ₂ is set to a value larger than the discharge reference value G ₁ and less than the maximum discharge power E. In FIG. 2, the discharge efficiency does not change much when the discharge power is from 2000 W to 1500 W. On the other hand, when the discharge efficiency is from 1500 W to 1000 W, the discharge efficiency gradually deteriorates. Therefore, in this embodiment, 1500 W discharge efficiency starts to gradually deteriorate discharge reference value G ₂ is set. The discharge reference value G ₂ is. Just the intermediate value of the maximum discharge power E and discharge reference value G _1.

In step S210, EMS60, the judgment whether or not by the above formula (3) right-hand side the following formula was changed to discharge reference value G ₂ (4), there is a battery in which the discharge power is less than the discharge reference value G ₂ To do.
(AB- (E × (F-1))) <G ₂ ... (4)

The EMS 60 shifts to step S220 when the above equation (4) is satisfied (step S210: YES). On the other hand, EMS60 shifts to step S230 when the above equation (4) is not satisfied (step S210: NO).

In step S220, the EMS 60 substitutes the value of the discharge reference value G ₂ into the discharge reference value G. When the process of step S220 is completed, the EMS 60 shifts to step S200.

In step S230, the EMS 60 issues a discharge instruction to the F storage batteries. At this time, the EMS 60 issues a discharge instruction to the storage batteries in the F unit (from the first to the F position) having a higher discharge priority, and also issues a standby instruction to the other storage batteries. Further, the EMS 60 does not set a discharge upper limit value for the F storage batteries. As a result, the EMS 60 discharges the storage batteries having a discharge priority of 1st to F in a state where they can be discharged up to the maximum discharge power E (2000W). When the process of step S220 is completed, the EMS 60 ends the process of the main flow.

As described above, the discharge efficiency does not change much when the discharge power is from 2000 W to 1500 W. Therefore, when the discharge power of the storage battery on the most upstream side is the discharge reference value G ₂ (1500 W) or more (step S210: NO), the storage battery is discharged as it is (even if the discharge upper limit value is not set). Efficiency hardly deteriorates. Therefore, in such a case, the EMS 60 discharges the storage battery in a state where it can be discharged up to the maximum discharge power E (2000 W).

Next, the process of the discharge instruction subroutine with the discharge upper limit value (step S200 in FIG. 4) will be described with reference to FIG.

The discharge instruction subroutine with a discharge upper limit value (hereinafter, referred to as “upper limit instruction process”) is a process of setting the discharge upper limit values H to _F and issuing a discharge instruction to the storage battery. The subscript of the discharge upper limit value H corresponds to the discharge priority. Specifically, the discharge limit H ₁ are those discharge priority shows the discharge limit of 1-position of the storage battery, the discharge limit H _F are those discharge priority shows the discharge limit of F-position of the accumulator Is. In the upper limit instruction process, the discharge upper limit values H1 to _F are calculated using the discharge instruction number F calculated (substituted) in the main flow, the discharge reference value G, etc., and the discharge upper limit values _H1 to appropriately calculated for the storage battery _{. I am trying} to set _F.

Note that "calculates the discharge limit _{H 1 to F",} the value of the resulting discharge limit _{H 1 to F} calculated by the arithmetic processing unit of EMS60, secured in the storage unit of EMS60 Refers to storing in an area. Further, "setting the discharge upper limit values H1 to _F " means that the signal relating to the values of the discharge upper limit values H1 to _F is output to the hybrid power conditioner 23, 33, 43, 53, so that the discharge priority is ranked first. from points to be issued against battery to F position, an instruction to not discharge large discharge power than the discharge limit H _{1 to F.}

The specific contents of the upper limit instruction processing will be described below.

First, in step S310, EMS60 substitutes the value of the discharge reference value G to discharge the upper limit H _{F (discharge} limit of the lowest battery in the battery discharging). By this, the 1000W or 1500W is substituted into the discharge limit _{H F.} Specifically, when the process proceeds from step S190 to limit instruction processing, so that the 1000W is assigned to the discharge limit H _F. Also, when the process proceeds from step S220 to limit instruction processing, so that the 1500W is assigned to the discharge limit _{H F.} When the process of step S310 is completed, the EMS 60 shifts to step S320.

In step S320, the EMS 60 calculates the distributed discharge power l ₀ . The distributed discharge power l is a value used for calculating the discharge upper limit values H1 to _F-1 . The distributed discharge power l is allocated in order from the storage battery having the highest discharge priority in the processes of steps S330 to S370 described later. For example, when the distributed discharge power l is allocated to a storage battery having a discharge priority of 1st to 3rd, a part of the distributed discharge power l (initial value) is first allocated to a storage battery having a discharge priority of 1st, and remains. The generated power is allocated to the storage battery having the second highest discharge priority, and the remaining power is allocated to the storage battery having the third highest discharge priority. The distributed discharge power l ₀ is an initial value of the distributed discharge power l in such allocation. The distributed discharge power l _{0 according} to the present embodiment is a power that is insufficient with respect to the required total discharge power (AB) when it is assumed that the F storage batteries are discharged at the discharge reference value G. The EMS 60 calculates the distributed discharge power l ₀ by the following equation (5). When the process of step S320 is completed, the EMS 60 shifts to step S330.
l ₀ = ABG × F ... (5)

When the EMS 60 shifts to step S330, the process of step S330 to step S370 is repeated. Specifically, when the EMS 60 shifts from step S320 to step S330, first, "1" is assigned to the variable n, and the processes of steps S330 to S370 are performed. Then, the EMS 60 increments the variable n and performs the processes of steps S330 to S370 again. The EMS 60 repeats such a process until the variable n becomes “F-1”. The variable n indicates the value of the discharge priority in the iterative processing from step S330 to step S370. In the present embodiment, the maximum number of discharge instructions F is "4", so that the variable n is a value in the range of "1" to "3".

In step S330, the EMS 60 calculates the discharge upper limit value H _n using the following formula (6).
H _n = G + l _n-1 × 2 / (F-n + 1) ... (6)
In the above equation (6), the second term (l _n-1 × 2 / (Fn + 1)) on the right side indicates the power allocated to the storage battery having the nth discharge priority. At least a part of the distributed discharge power l _n-1 is allocated to the n-position storage battery according to the second term. Also, when calculating the discharge limit _{H F-1} of F-1 position of the battery (the variable n is "F-1"), the denominator (F-n + 1) becomes "2". Therefore, all the distributed discharge power l _n-1 is allocated to the storage battery at the F-1 position (finally allocated). In this way, all the distributed discharge power l ₀ can be allocated to the storage batteries in the 1st to F-1 positions. In the above formula (6), by adding the allocated value (distribution value) in the discharge reference value G, and calculates the discharge limit H _n. As a result, the EMS 60 sets the discharge upper limit value H _n to a value equal to or higher than the discharge reference value G. Further, EMS60 the power discharge priority distribution discharge power l ₀ is the allocate preferentially to the higher battery.

Specifically, since the variable n is a value in the range of "1" to "3", in the above equation (6), the value of the distributed discharge power l _{0 to 2} is set according to the value of the variable n. Used. As described above, the distributed discharge power l ₀ is an initial value of the distributed discharge power l. Further, the distributed discharge power l ₁ indicates the power remaining by allocating the distributed discharge power l ₀ to the storage battery having the first discharge priority, and the distributed discharge power l ₂ indicates the distributed discharge power l to the storage battery having the second discharge priority. ₁ is assigned to indicate the remaining power. Therefore, the smaller the subscript number (variable n), the larger the value of the distributed discharge power l.

Therefore, the higher the discharge priority (the smaller the variable n), the larger the numerator (l _n-1 × 2) in the second term on the right side of the above equation (6). Although the denominator (F-n + 1) of the second term also increases as the discharge priority is higher, the second term (l _n-1 x 2 / (F) according to the discharge priority (variable n)). The calculation result of −n + 1)) becomes larger as the discharge priority is higher. According to the second term of the above equation (6), the storage battery having the higher discharge priority is preferentially allocated (more power).

When the process of step S330 is completed, the EMS 60 shifts to the process of step S340.

In step S340, the EMS 60 determines whether or not the discharge upper limit value H _n is larger than the maximum discharge power E (2000 W). The EMS 60 shifts to step S350 when the discharge upper limit value H _n is larger than the maximum discharge power E (step S340: YES). On the other hand, the EMS 60 shifts to step S360 when the discharge upper limit value H _n is equal to or less than the maximum discharge power E (step S340: NO).

In step S350, the EMS 60 corrects the discharge upper limit value H _n to the maximum discharge power E (2000 W). Thus, EMS60 can the value of the discharge limit H _n to an appropriate value (not to exceed the maximum discharge power E). When the process of step S350 is completed, the EMS 60 shifts to the process of step S360.

In step S360, the EMS 60 determines if the variable n is not "F-1". The EMS 60 shifts to step S370 when the variable n is not “F-1” (step S360: YES). On the other hand, when the variable n is "F-1" (step S360: NO), the EMS 60 exits the repeated processing of steps S330 to S370 and shifts to step S380.

In step S370, EMS60 calculates a distribution discharge power _{l n} (discharge priority remained Allocate distribution discharge power _{l n-1} to n-position of the battery power). At this time, EMS60, using the following equation (7), calculates a distribution discharge power _{l n.}
l _n = l _n-1- (H _n- G) ... (7)
Here, in the above formula (7), (H _{n −} G) is a value (the second term of the above formula (6)) in which the distributed discharge power l _n-1 is assigned to the discharge upper limit value H _n .

EMS60, by repeating from such step S330 until the step S370 the variable n becomes "F-1", among the discharge limit _{H 1 to F,} the value of calculated (discharge reference value G in step S310 assignment ) Calculate the discharge upper limit values H1 to _{F -1} other than the discharge upper limit value _HF that was not performed. In this way, the EMS ₆₀ calculates the discharge upper limit values _H1 to F of the F storage batteries.

In step S380, the EMS 60 issues a discharge instruction to the F storage batteries. At this time, the EMS 60 issues a discharge instruction to the storage batteries in the F unit (from the first to the F position) having a higher discharge priority, and also issues a standby instruction to the other storage batteries. Further, the EMS 60 sets a discharge upper limit value (issues an instruction of the discharge upper limit value) for the storage batteries excluding the most upstream storage battery among the storage batteries issuing the discharge instruction. As a result, the EMS 60 discharges the storage batteries excluding the storage battery on the most upstream side among the storage batteries having the discharge priority of 1st to F in a state where they can be discharged to the discharge upper limit value. Further, the EMS 60 discharges the most upstream storage battery in a state where it can be discharged up to the maximum discharge power E (2000 W). When the process of step S380 is completed, the EMS 60 ends the process of the upper limit instruction process.

Next, a specific example of the main flow and the upper limit instruction processing will be described.

In the following, specific examples will be described separately for two cases C1 and C2 having different total power consumption A. First, a specific example will be described with reference to FIGS. 3 and 6 by taking case C1 in which the total power consumption A is 2400 W as an example. In addition, in FIG. 3 and FIG. 6, for convenience of explanation, it is assumed that the photovoltaic power generation units 21, 31, 41, and 51 do not generate power (the total photovoltaic power generation B is 0 W).

FIG. 3 shows a state before the main flow and the upper limit instruction process are performed. In the state shown in FIG. 3, the discharge priority is as follows: the storage battery 52 is the first, the storage battery 42 is the second, the storage battery 32 is the third, and the storage battery 22 is the fourth. Further, the two storage batteries 42 and 52 having the highest discharge priority are discharged, of which the discharge power of the storage battery 42 on the downstream side is 2000 W (maximum discharge power E) and the discharge power of the storage battery 52 on the upstream side is 400 W (maximum discharge power E). The discharge efficiency is poor).

When the main flow is performed in the above state, the EMS 60 determines that the total power consumption A (2400 W) is larger than the total photovoltaic power generation power B (0 W) (step S120: YES), and the above equation (2) ) To calculate the quotient (“1.2”) (see the formula below).
F = (2400W-0W) /2000W = 1.2

Then, the EMS 60 rounds up after the decimal point of the calculated quotient (“1.2”) to calculate the number of discharge instructions F (“2”) (step S150). After that, the EMS 60 substitutes the value into the above formula (3) and determines that there is a storage battery whose discharge power is less than the discharge reference value G ₁ (step S160: NO, step S180: YES, see the following formula).
(2400W-0W- (2000W x (2-1))) <1000W
400W <1000W

In this case, EMS60 is the discharge reference value G by substituting the discharge reference value _{G 1} of the value (1000W), to perform the upper limit instruction process (step S190 · S200).

In the upper limit instruction process, the EMS 60 first substitutes the value (1000 W) of the discharge reference value G ₁ into the discharge upper limit value H ₂ of the storage battery 42 having the second highest discharge priority (F position) (step S310). Then, the EMS 60 substitutes the value into the above formula (5) to calculate the distributed discharge power l ₀ (400 W) (step S320, see the following formula).
l ₀ = 2400W-0W-1000W x 2
= 400W

Then, the EMS 60 substitutes the value into the above formula (6) to calculate the discharge upper limit value H ₁ (1400 W) (step S330, see the following formula).
H ₁ = 1000W + 400W x 2 / (2-1 + 1)
= 1000W + 400W x 2/2
= 1400W

After that, in EMS60, the discharge upper limit value H ₁ (1400 W) is equal to or less than the maximum discharge power E (2000 W) (step S340: NO), and the variable n (“1”) is F-1 (“1”). Since there is (step S360: NO), a discharge instruction is issued to the storage batteries 42 and 52 having the first and second discharge priorities (step S380). Further, the EMS 60 issues a standby instruction to the other storage batteries 22 and 32. Further, the EMS 60 has a discharge upper limit value H ₂ (substituting the value of the discharge reference value G) first calculated (substituting the value of the discharge reference value G) into the storage battery 42 on the downstream side (discharge priority is second) among the storage batteries 42 and 52. 1000W) is set.

FIG. 6 is a diagram showing a state after the main flow and the upper limit instruction process are performed (the discharge upper limit value H ₂ is set) from the state shown in FIG. In FIG. 6, the storage batteries 42 and 52 for which the discharge instruction is issued are shown by solid lines, and among them, the storage batteries 42 in which the discharge upper limit value H ₂ (1000 W) is set are shown by thick solid lines. In addition, the storage batteries 22 and 32 for which the standby instruction has been issued are shown by a two-dot chain line. Further, in the table shown at the lower right of FIG. 6, “no distribution” indicates the discharge power when the discharge upper limit value H ₂ is not set (state in FIG. 3). Further, in the table shown at the lower right of FIG. 6, “with distribution” indicates the discharge power when the discharge upper limit value H ₂ is set.

The discharge power of the storage battery 42 is reduced from 2000 W to 1000 W because the discharge upper limit value H ₂ (1000 W) is set. As a result, the storage battery 52 on the upstream side discharges the remaining 1400 W of power, which is insufficient for the total power consumption (2400 W) of each house H.

According to such a configuration, the discharge power of the upstream storage battery 52 can be increased by the amount of the reduced discharge power of the downstream storage battery 42 (1000 W) ("" in the table shown at the lower right of FIG. Storage battery 52 (1st place) ”). As a result, the discharge power of the storage battery 52 can be increased from 400 W to 1400 W, and the discharge efficiency can be increased from 80% to about 90%. According to this, deterioration of the discharge efficiency of the storage battery 52 can be suppressed. As a result, it is possible to suppress an increase in power loss and effectively utilize the power.

Further, the storage battery 42 shown in FIG. 6 is discharged at 1000 W, which does not significantly deteriorate the discharge efficiency, although the discharge power is reduced as compared with the state before the discharge upper limit value H ₂ is set (FIG. 6). See "Battery 42 (2nd place)" in the table shown in the lower right). As a result, the EMS 60 can suppress the deterioration of the discharge efficiency by preventing the discharge power of the storage battery 42 (the storage battery that reduces the discharge power) from being reduced more than necessary. Thereby, the influence of the deterioration of the discharge efficiency of the storage battery 42 caused by setting the discharge upper limit value H ₂ can be alleviated. In addition, all the storage batteries 42 and 52 to be discharged can be discharged in a state where the discharge efficiency does not deteriorate so much (1000 W or more).

Further, although the EMS 60 calculates the discharge upper limit value H ₁ (1400 W) of the storage battery 52 on the upstream side in the upper limit instruction process (step S330), the discharge upper limit value H ₁ is set for the storage battery 52. Not. Therefore, storage battery 52 can discharge the power higher than the discharge limit H _1. According to such a configuration, even if the total power consumption of each house H increases from the state shown in FIG. 6 (for example, even if it increases from 2400 W to 3000 W), the discharge power of the storage battery 52 is increased to increase the discharge power of each house. It is possible to cope with the rapid increase in the power consumption of H.

Next, a specific example will be described with reference to FIGS. 7 and 8 by taking case C2 in which the total power consumption A is 5100 W as an example. In addition, in FIG. 7 and FIG. 8, for convenience of explanation, it is assumed that the photovoltaic power generation units 21, 31, 41, and 51 are not generating power (the total photovoltaic power generation B is 0 W).

FIG. 7 shows a state before the main flow and the upper limit instruction process are performed. In the state shown in FIG. 7, the discharge priority is as follows: the storage battery 32 is the first, the storage battery 22 is the second, the storage battery 42 is the third, and the storage battery 52 is the fourth. In addition, the three storage batteries 22.32.42 with the highest discharge priority are discharged, and the discharge power of the two storage batteries 22.32 on the downstream side is 2000 W (maximum discharge power E), which is the most upstream side. The discharge power of the storage battery 42 is 1100 W.

When the main flow is performed in the above state, the EMS 60 calculates the number of discharge instructions F (“3”) (step S110, step S120: YES, step S150). Then, the EMS 60 determines that there is a storage battery whose discharge power is less than the discharge reference value G ₂ by using the above formula (4) (1100 W <1500 W) (step S160: NO, step S180: NO, step S210: YES). In this case, the EMS 60 substitutes the value (1500 W) of the discharge reference value G ₂ into the discharge reference value G and executes the upper limit instruction process (steps S220 and S200).

In the upper limit instruction process, the EMS 60 first substitutes the value (1500 W) of the discharge reference value G ₂ into the discharge upper limit value H ₃ of the storage battery 42 having the third discharge priority (F position) (step S310). Then, the EMS 60 calculates the distributed discharge power l ₀ (600 W) using the above formula (5) (5100 W-0W-1500 W × 3 units) (step S320).

Then, the EMS 60 calculates the discharge upper limit value H ₁ (1900 W) of the storage battery 32 having the first discharge priority by using the above formula (6) (1500 W + 600 W × 2 / (3-1 + 1)) (step S330). .. After that, the EMS 60 calculates the distributed discharge power l ₂ (200 W) using the above formula (7) (600 W- (1900 W-1500 W)) (step S340: NO, step S360: YES, step S370).

The EMS 60 increments the variable n and calculates the discharge upper limit value H ₂ (1700 W) of the storage battery 22 having the second highest discharge priority by using the above formula (6) (1500 W + 200 W × 2 / (3-2 + 1)). (Step S330). Then, the EMS 60 issues a discharge instruction to the storage batteries 22.32.42 having the first to third discharge priorities (step S340: NO, step S360: NO, step S380). Further, the EMS 60 issues a standby instruction to the other storage battery 52. Further, the EMS 60 sets the discharge upper limit values H ₁ (1900 W) and H ₂ (1700 W) in the _two storage batteries 22 and 32 on the downstream side of the storage batteries 22 and 32.42.

Figure 8 is a diagram showing a state after the main flow and the upper limit instruction process from the state shown in FIG. 7 is performed (discharge limit H ₁ · H ₂ is set). In FIG. 8, a storage battery 22, 32, 42 which discharge instruction is issued by the solid line, of which the discharge limit H ₁ · H ₂ indicates a storage battery 22, 32 that are configured by the thick solid line. Further, the storage battery 52 for which the standby instruction has been issued is indicated by a two-dot chain line. Also, of the table shown in the lower right of FIG. 8, "no distribution" indicates the discharge power when not set discharge limit H ₁ · H ₂ (the state in FIG. 7). Also, of the table shown in the lower right of FIG. 8, "there distribution" indicates the discharge power of setting the discharge limit H ₁ · H _2.

The discharge power of the storage battery 22 is reduced from 2000 W to 1700 W because the discharge upper limit value H ₂ (1700 W) is set. Further, in the storage battery 32 as well, the discharge power is reduced from 2000 W to 1900 W because the discharge upper limit value H ₁ (1900 W) is set as in the storage battery 22. As a result, the storage battery 42 on the most upstream side among the storage batteries 22, 32, and 42 to be discharged discharges the remaining 1500 W of power that is insufficient for the total power consumption (5100 W) of each house H.

As described above, the EMS 60 sets the discharge reference value G as the discharge reference when the discharge power of the most upstream storage battery 42 among the discharge batteries 22.32.42 is large to some extent (1000 W or more and less than 1500 W, see FIG. 7). The discharge reference value G ₂ (1500 W) is used instead of the value G ₁ (1000 W). According to such a configuration, it is possible to raise the discharge reference value G (the lowest line of discharge limit value) and the discharge reference value G ₁ to the discharge reference value G _2, the discharge limit H _{1 · 2} is set The amount of decrease in the discharge power of the storage batteries 22 and 32 can be made smaller. Thereby, the influence of deterioration of the discharge efficiency of the storage batteries 22 and 32 (storage batteries in which the discharge power is reduced) caused by setting the discharge upper limit values H1 _{and 2} can be effectively mitigated.

Here, in the state shown in FIG. 8, since the discharge priority is positioned upstream of the 1-position of the battery 32 is the 2-position of the battery 22, typically a (discharge limit H ₁ · H ₂ If it is not set), the storage battery 22 having a lower discharge priority will be discharged preferentially. Further, when three or more storage batteries are discharged, the storage batteries 22 and 32 are discharged at the maximum discharge power E (2000 W), respectively. As described above, depending on the relationship between the upstream and the downstream, the storage batteries 22, 32, 42, and 52 may not be able to have a larger discharge power than the lower storage battery even if the discharge priority is higher.

Therefore, in the present embodiment, the discharge upper limit value H ₁ (1900 W) of the storage battery 32 having the first discharge priority is set higher than the discharge upper limit value H ₂ (1700 W) of the storage battery 22 having the second highest discharge priority. As a result, the discharge power of the storage battery 32 having a higher discharge priority can be made larger than the discharge power of the storage battery 22 having a lower discharge priority, regardless of the relationship between the upstream and the downstream. As a result, the storage battery 32 having a higher discharge priority can be discharged preferentially.

As described above, the power supply system 1 according to the present embodiment discharges a plurality of storage batteries 22.32.42.52 capable of discharging power to each house H (load) and the storage batteries 22.32.42.52. The EMS 60 is provided with an EMS 60 (control unit) for controlling the discharge power of some of the two or more storage batteries 22.32.42.52 to be discharged. Is less than the discharge reference values G ₁ and G ₂ (reference values) set in consideration of the discharge efficiency of the storage batteries 22, 32, 42, and 52 (step S180: NO, step S210: NO). The discharge power of the storage batteries excluding some of the storage batteries is reduced (steps S190 / S200, steps S220 / S200).

With this configuration, the discharge power of the storage battery with good discharge efficiency (“the storage battery excluding some of the storage batteries”) is reduced, and the discharge efficiency is poor (“some storage batteries”). The discharge power of the can be increased. As a result, it is possible to suppress deterioration of the discharge efficiency of the storage battery.

Further, the EMS 60 reduces the discharge power by setting the discharge upper limit values H ₁ to ₄ , which are the upper limit values of the discharge power of the storage batteries 22, 32, 42, 52, and the discharge reference value. The discharge upper limit values H1 to ₄ are set (steps S310 to S370) so that the values are G ₁ and G ₂ or more and less than the maximum discharge power E of the storage batteries 22, 32, 42, and 52. is there.

With this configuration, storage battery set the discharge limit (e.g., the storage battery 22 is set to discharge limit H ₁₎ reduction of discharge power of the can be kept to a certain range. Therefore, it is possible to mitigate the effect of deterioration of the discharge efficiency of the storage battery (“the storage battery excluding the part of the storage battery”) caused by setting the discharge upper limit value.

Further, the reference value includes a plurality of discharge reference values G ₁ and G ₂ having different values, and the EMS 60 includes the discharge power of some of the storage batteries and the plurality of discharge reference values G ₁ and G _2. The discharge upper limit value is set (steps S190 / S200, steps S210 / S200) so that the value is equal to or higher than the discharge power and equal to or higher than the discharge reference value closest to the discharge power. is there.

With this configuration, the discharge upper limit values H1 to ₄ can be increased according to the discharge power of some storage batteries. As a result, the amount of decrease in the discharge power of the storage battery for which the discharge upper limit value is set can be effectively reduced. Therefore, it is possible to mitigate the effect of deterioration of the discharge efficiency of the storage battery (the storage battery excluding some storage batteries) caused by setting the discharge upper limit value.

Further, a discharge priority (priority regarding discharge) is set for the storage batteries 22.32.42.52, and the EMS60 has a discharge upper limit value H for the storage batteries 22.32.42.52 having a higher discharge priority. _The discharge upper limit values H1 to ₄ are set so that ₁ to ₄ become higher (steps S310 to S380).

With this configuration, the discharge upper limit values H ₁ to ₄ can be optimized according to the discharge priority.

Further, the EMS 60 is based on the assumption that the same number of storage batteries 22, 32, 42, and 52 as the number of discharge instructions F are discharged with the same discharge power as the discharge reference value G (G ₁ , G ₂ ). , The insufficient distributed discharge power l ₀ for each house H is calculated (step S320), and the power of the distributed discharge power l ₀ is given priority to the storage batteries 22.32.42.52 having the higher priority. The discharge upper limit is calculated by calculating the distributed value (l _n-1 × 2 / (Fn + 1)) and adding the discharge reference values G (G ₁ and G ₂ ) and the distributed value. The values H ₁ to ₄ are calculated (steps S330 to S370).

With this configuration, it is possible to easily calculate the discharge upper limit values H _{1 to 4} according to the discharge priority.

Further, the plurality of storage batteries 22, 32, 42, 52 are connected in series with each other in a distribution line L (power supply path) connecting the system power supply S and each house H, and the EMS 60 is discharged. The discharge upper limit values H1 to ₄ are not set for the storage battery (on the upstream side) closest to the system power supply S among the storage batteries 22, 32, 42, and 52 of the unit or more (step S380). ..

With such a configuration, it is possible to cope with a rapid increase in power consumption of each house H.

The EMS 60 according to the present embodiment is an embodiment of the control unit according to the present invention.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above configuration, and various modifications can be made within the scope of the invention described in the claims.

For example, in the present embodiment, the power supply system 1 is applied to the residential block T, but is not limited to this, and may be applied to, for example, an apartment house or an office. Good.

Further, in the present embodiment, the number of units in each house H is set to 4, but the number is not limited to this and can be any number.

Further, in the present embodiment, the number of storage batteries 22, 32, 42, and 52 is set to 4, but the number is not limited to this, and any number of 2 or more can be used.

Further, in the present embodiment, the maximum discharge power E is assumed to be 2000 W, but this value is an example and may be a value other than 2000 W.

Further, the maximum discharge powers of the storage batteries 22, 32, 42, and 52 are all the same, but they are different from each other depending on the scale of the house owned (for example, the building area and the total floor area). May be good. In this case, the EMS 60 may perform the main flow processing by individually considering the maximum discharge power and the discharge efficiency of the storage batteries 22, 32, 42, and 52.
Specifically, for example, the EMS 60 compares the maximum discharge power of the storage battery having the first discharge priority and the required total discharge power (AB) in the calculation of the number of discharge instructions F (step S150). If the maximum discharge power is less than the required total discharge power (AB), the EMS60 is required by adding the maximum discharge power of the storage battery whose discharge priority is one lower (second place) to the maximum discharge power. Compare with total discharge power (AB). The EMS 60 repeats such addition and comparison, and determines how many storage batteries's maximum discharge powers should be added up to be equal to or more than the required total discharge powers (AB). Then, the EMS 60 may calculate the discharge instruction number F based on the determination result.
Further, the EMS 60 sets a discharge reference value for each of the storage batteries 22, 32, 42, and 52 in consideration of the discharge efficiency in determining whether or not there is a storage battery less than the discharge reference value (steps S180 and S210). Then, the EMS 60 may calculate the discharge power of the storage battery on the most upstream side among the storage batteries to be discharged, and determine whether the calculation result is less than the discharge reference value corresponding to the storage battery.

Further, although the storage batteries 22.32.42.52 (first power storage system 20 to fourth power storage system 50) are connected in series with each other, the discharge power and discharge efficiency of the storage batteries 22.32.42.52 As long as the relationship with each other is different from each other, they may be connected in parallel with each other. Specifically, the storage batteries 22, 32, 42, and 52 connected in parallel discharge with the same discharge power. However, when the relationship between the discharge power of the storage batteries 22/32/42/52 and the discharge efficiency is different from each other, even if the same discharge power is used for discharging, the discharge efficiencies of these storage batteries 22/32/42/52 are high. They will be different from each other, and the discharge efficiency of some storage batteries may be extremely worse than that of other storage batteries. In such a case, the storage batteries 22, 32, 42, and 52 may be connected in parallel to each other because the deterioration of the discharge efficiency can be suppressed by setting the discharge upper limit values H1 to ₄ .

Further, each power storage system 20, 30, 40, 50 is provided with a photovoltaic power generation unit 21, 31, 41, 51 that generates electricity using sunlight, but uses natural energy other than sunlight. It may be equipped with a device for generating electricity (wind power generation or hydroelectric power generation).

Further, the electric power supply system 1 may be provided with at least storage batteries 22, 32, 42, and 52 as devices for supplying electric power to each house H, and necessarily includes solar power generation units 21, 31, 41, and 51. do not have to.

Further, in the present embodiment, the charging / discharging of the storage batteries 22/32/42/52 is controlled by the EMS 60, but the device for controlling the storage batteries 22/32/42/52 is not limited to the EMS 60. , Other equipment (for example, hybrid power conditioner 23, 33, 43, 53, etc.) may be used.

Further, the EMS 60 charges the storage batteries 22, 32, 42, and 52 when the electric power from the photovoltaic power generation units 21, 31, 41, and 51 is surplus (step S120: NO, steps S130, S140). ), The surplus electric power may be reverse-flowed, for example, without being limited to this. In this case, the storage batteries 22, 32, 42, and 52 do not charge the power from the photovoltaic power generation units 21, 31, 41, and 51, but instead charge the power from the grid power source S at an appropriate timing (for example, at midnight). It should be charged (at the time of day, etc.).

Further, in step S120, the EMS 60 uses the total power consumption A and the total photovoltaic power generation B to determine whether the power from the photovoltaic power generation units 21, 31, 41, and 51 is surplus. The determination method is not limited to this embodiment. The EMS 60 is, for example, based on the detection result of the fourth sensor 14 of the sensor unit 10 (the sensor arranged on the most upstream side of the sensor unit 10), and the power from the photovoltaic power generation unit 21.31.41.51. May be determined if there is a surplus.

Further, in the present embodiment, the discharge reference value G ₁ is assumed to be 1000 W, but the value of the discharge reference value G ₁ is not limited to this, and the discharge power of the storage batteries 22, 32, 42, 52 is not limited to this. It can be set as appropriate according to the relationship between the discharge efficiency and the discharge efficiency. It is desirable that the discharge reference value G ₁ (value to be compared with the discharge power first) is a value small to some extent, specifically, a value less than half of the maximum discharge power E. Further, the discharge reference value G ₂ is assumed to be 1500 W, but the value of the discharge reference value G ₂ is limited to this if it is larger than the discharge reference value G _{1 and} less than the maximum discharge power E (2000 W). It's not a thing. The discharge reference value G ₂ is a value that is small to some extent, specifically, a value that is less than half of the total value of the maximum discharge power E and the discharge reference value G ₁ (the discharge reference value one step before). desirable.

Further, in the present embodiment, two discharge reference values are set (discharge reference values G ₁ and G ₂ ), but the number of discharge reference values to be set is not limited to this, and one or three or more are set. It may be set.

Further, the EMS 60 issues a discharge instruction to the storage battery having the highest discharge priority when the number of discharge instructions F is "1" (step S160: YES), but the present invention is not limited to this. The discharge of the storage battery may be appropriately controlled in consideration of the discharge efficiency. Specifically, EMS60 may issue a discharge instruction to the battery only when discharge power of the storage battery is discharged the reference value G ₁ or more. According to such a configuration, when one storage battery is discharged, it is possible to suppress deterioration of the discharge efficiency of the storage battery.

Further, the method of allocating the distributed discharge power l is not limited to the present embodiment (the above equation (6)), and may be allocated by another method. Further, the distributed discharge power l does not necessarily have to be preferentially allocated to the storage batteries having a higher discharge priority, and may be evenly allocated to the storage batteries to be discharged regardless of the discharge priority.

1 Power supply system 22 ・ 32 ・ 42 ・ 52 Storage battery 60 EMS (control unit)
H Each house (load)

Claims (6)

Multiple storage batteries that can discharge power to the load,
A control unit that controls the discharge of the storage battery,
Equipped with
The control unit
Of the two or more storage batteries to be discharged, when the discharge power of some of the storage batteries is less than the reference value set in consideration of the discharge efficiency of the storage batteries, the storage batteries excluding some of the storage batteries Reduce discharge power,
Power supply system. The control unit
By setting the discharge upper limit value which is the upper limit value of the discharge power of the storage battery, the discharge power is reduced.
The discharge upper limit value is set so that the value is equal to or more than the reference value and less than the maximum discharge power of the storage battery.
The power supply system according to claim 1. The reference value is
Contains multiple discharge reference values with different values,
The control unit
The discharge power of some of the storage batteries is compared with the plurality of discharge reference values, and the discharge upper limit value is set so as to be equal to or higher than the discharge power and equal to or higher than the discharge reference value closest to the discharge power. Set,
The power supply system according to claim 2. The storage battery is set with a priority regarding discharge.
The control unit
The discharge upper limit value is set so that the storage battery having a higher priority has a higher discharge upper limit value.
The power supply system according to claim 2 or 3. The control unit
Assuming that the same number of the storage batteries as the number of discharged batteries are discharged with the same discharge power as the reference value, the distributed discharge power insufficient for the load is calculated.
A distribution value, which is a value obtained by preferentially distributing the electric power of the distributed discharge power to the storage battery having a higher priority, is calculated.
The discharge upper limit value is calculated by adding the reference value and the distribution value.
The power supply system according to claim 4. The plurality of storage batteries
They are connected in series with each other in the power supply path connecting the grid power supply and the load.
The control unit
The discharge upper limit value is not set for the storage battery closest to the system power supply among the two or more storage batteries to be discharged.
The power supply system according to any one of claims 2 to 5.

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